FIELD OF THE INVENTION This invention is directed to novel and known sulfur containing compounds and pharmaceutical acceptable salts thereof that have utility as antifungal agents and as antiproliferative agents against mammalian cells, in particular cancer cells and most particularly leukemia-derived cells. The invention provides a method for synthesizing certain of the sulfur containing compounds that is more efficient than previously known methods.

BACKGROUND OF THE INVENTION There is an enormous need worldwide for novel, safe, effective therapeutics in the clinical treatment of cancers. The majority of chemotherapeutics presently available are less than ideal as they show non-specific, genotoxic killing of both normal as well as tumour cells. Recent success stories suggest natural products research will uncover new molecules to help fight the cancer problem (Cardenas, M. E., Sanfridson, A., Cutler, N. S., and Heitman, J. (1998) Signal-transduction cascades as targets for therapeutic intervention by natural products. Trends Biotechnol. 16 : 427-33, Marks, P. A., Richon, V. M. and Rifkind, R. A. (2000) Histone deacetylase inhibitors : inducers of differentiation or apoptosis of transformed cells. J Natl Cancer Inst. 92 : : 1210-6). For example, the taxanes (taxol), derived from the bark of the yew tree, have emerged as effective anti-tumour agents in a wide variety of malignancies (Vaishampayan, U., Parchment, R. E., Jasti, B. R., and Hussain, M. (1999) Taxanes : an overview of the pharmacokinetics and pharmacodynamics.

Urology 54, 22-9, Watsh, V., and Goodman, J. (1999) Cancer chemotherapy, biodiversity, public and private property : the case of the anti-cancer drug taxol. Soc Sci Med 49, 1215- 25). Enormous experimental effort has led to the identification of organosulfur compound (OSCs) as the active components of medicial plants such as garlic, onions, the leaves of the Mahogany tree, yet this knowledge is primarily applied to nutritional aspects of cancer prevention strategies and not directly to acute treatment protocols (Fukushima, S., Takada, N., Hori, T., and Wanibuchi, H. (1997) Cancer prevention by organosulfur compounds from garlic and onion. J Cell Biochem Suppl 27, 100-5, Jiao, D., Smith, T. J., Yang, C. S., Pittman, B., Desai, D., Amin, S., and Chung, F. L. (1997) Chemopreventive activity of thiol conjugates of isothiocyanates for lung tumorigenesis. Carcinogenesis 18, 2143-7, Reddy, B. S., Rao, C. V., Rivenson, A., and Kelloff, G. (1993) Chemoprevention of colon carcinogenesis by organosulfur compounds. Cancer Res 53, 3493-8, Wargovich, M. J.

(1987) Diallyl sulphide, a flavor component of garlic (Allium sativum), inhibits

dimethylhydrazine-induced colon cancer. Carcinogenesis 8, 487-9, Wargovich, M. J., Imada, O., and Stephens, L. C. (1992) Initiation and post-initiation chemopreventive effects of diallyl sulphide in esophageal carcinogenesis. Cancer Lett 64, 39-42, Wargovich, M. J., Woods, C., Eng. V. W., Stephens, L. C. and Gray, K. (1988) Chemoprevention of N- nitrosomethylbenzylamine-induced esophageal cancer in rats by the naturally occurring thioether, diallyl sulphide. Cancer Res 48, 6872-5). It appears that the knowledge gained from natural products research is not widely and immediately exploited for the treatment of cancer primarily because of technical limitations. For instance, only a very low yield of active metabolite can be recovered from typical natural sources, the extraction procedure often leads to mixtures of structural relatives of varying specific activity compared to the target natural product, there can be environmental issues associated with harvesting medicinal plants, and mining the active component is often labour-intensive, difficult to quality assure and is expensive to produce in large quantities. Numerous studies have shown that OSCs have antiproliferative potential (Jogia, MK, Andersen, RJ, Mantus, EK and Clardy, J (1989) Dysoxysulfone, a sulfur rich metabolite from the Fijian medicinal plant Dysoxylum Richii. Tetrahedron Letters 30 : 4919-4920, Block, E, DeOrazio, R and Thiruvazhi, M (1994) Simple total synthesis of biologically-active pentathiadecane natural- products, 2, 4, 5, 7, 9-pentathiadecane 2, 2, 9, 9-tetraoxide (dysoxysulfone), from Dysoxylum- Richii, and 2, 3, 5, 7, 9-pentathiadecane 9, 9-dioxide, the misidentified lenthionine precursor Se-3 from Shiitake mushroom (Lentinus-Edodes). J Org Chem 59 : 2273-2275, Perchellet, JP, Perchellet, EM and Belman, S (1990) Inhibition of DMBA-induced mouse skin tumorigenesis by garlic oil and inhibition of two tumor-promotion stages by garlic and onion oils. Nutr Cancer 14 : 183-93). Despite the documented biological activity of OSC (Block, E : The organosulfur chemistry of the genus Allium-implications for the organic chemistry of sulfur. Angew. Chem. Int. Ed. Engl. 31 : 1135-1178, 1992, Lea, MA : Organosulfur compounds and cancer. Adv Exp Med Biol 401 : 147-54, 1996), the key structural features that directly contribute to their antiproliferative activity remains unclear.

There is also a need for effective antifungal agents that are readily biodegradable and which can be used against a wide variety of pathogens in both animals and humans.

There are known sulfur containing compounds which have been found to be useful as antifungal agents. For example, U. S. Patents No. 5, 648, 354 issued July 15, 1997 to Bierer, et al and No. 5, 580, 897 issued December 3, 1996 to Bierer, et al and No. 5, 583, 235 issued December 10, 1996 to Bierer, et al disclose novel 1, 2-dithiin compounds having such utility.

In U. S. Patent No. 5, 698, 564 issued December 16, 1997 to Katsuyama, et al there are described diphenyl disulphide compounds having an inhibiting activity against the production of Interleukin-1 P (IL-1 ß) or the release of Tumor Necrosis Factor a (TNFa), which are useful in the treatment or prophylaxis of diseases such as chronic rheumatism and sepsis.

The literature contains a number of papers disclosing antifungal compounds of the type described herein. Baerlocher, Felix Jacob, et al Aust. J. Chem., 1999, 52, 167-172 entitled Structure-Activity Relationship for Selected Sulfur-Rich Antifungal Compounds reported that the inhibition of fungal growth correlates with the presence of both sulfone and sulphide functional properties. The disclosures of this paper are incorporated herein by reference.

In Langler, Richard Francis, et al Aust. J. Chem published Feb. 2000, and entitled A New Synthesis for Antifungal a-Sulfone Disulphides, there is described the preparation of several new a-sulfone disulphides using an a-ester sulphide precursor. These a-sulfone disulphides were all shown to be fungitoxic against Aspergillis niger and Aspergillis flavus.

The disclosures of this paper are incorporated herein by reference.

In 1989, Andersen et ai. reported the isolation and structure proof of dysoxysulfone (CH3SO2CH2SCH2SSCH2SO2CH3) (see Tetra. Lett. 30, 4919 (1989)). Sample size was limited and the compound showed some antibiotic activity.

In 1989, Block et al. described a synthesis for dysoxysulfone, which provided larger amounts (see Block et al., J. Org. Chem. 59, 2273 (1994)). They showed that dysoxysulfone and some related natural products were active against Candida albicans, a P388 murine leukemia cell line, Staphylococcus aureus, Bacillus subtilis, a human adrenocarcinoma cell line and a human ovarian carcinoma cell line.

U. S. Patent No. 4, 643, 994 granted to Block et al. described sulfur compounds like 3 as antithrombotic agents.

RSO2CH2CH=CHSSR'3 The patent describes the use of these compounds against"bacteria and fungi", as well as for"flavor enhancers in foods". In Block's patent, compounds like 2 of the formula RSO2CH2SSR'were inadvertently included. In 1987, Block et al. obtained a Certificate of Correction, which withdrew compounds like 2 from the patent.

The following publications are relevant to the present invention : Langler, Richard Francis, et al. : A New Synthesis for Antifungal a-Sulfone Disulphides.

Aust. J. Chem., 1999, 52, 1119-1121.

Wong, W. Wei-Lynn, et al. : Novel Synthetic Organosulfur Compounds Induce Apoptosis of Human Leukemic Cells. Anticancer Research 20 : 1367-1374 (2000).

Baerlocher, Felix Jakob, et al. : Structure-Activity Relationships for Selected Sulfur- Rich Antifungal Compounds. Aust. J. Chem., 1999, 52, 167-172.

Baerlocher, Felix Jakob, et al. : Antifungal Thiosulfonates : Potency with Some Selectivity. Aust. J. Chem., 2000, 53, 399-402.

Baerlocher, Felix Jakob, et al. : New and More Potent Antifungal Disulphides. Aust. J.

Chem., 2000, 53, 1-5.

"New Antifungal Disulphides : Approaching Submicrogram Toxicity", F. J. Baerlocher" M. O. Baerlocher, C. L. Chaulk, R. F. Langler and E. M. O'Brien, SulfurLett.,-in press

The disclosures of these references are incorporated herein by reference.

SUMMARY OF THE INVENTION In one aspect of the invention, there are provided novel sulfone disulphides of the general formula RSO2CH2SSR'I wherein R is phenyl or lower alkyl, and R'is lower alkyl or phenyl.

This invention provides specific novel sulfone disulphides of this general formula selected from the group consisting of C6H5SO2CH2SSCH3, CH3SO2CH2SSCH3, and CH3SO2CH2SSC6H5.

Another aspect of the invention provides a process for preparing a sulfone sulphide of the general formula I as described above, which comprises reacting a transition metal oxidant or a peroxyanhydride oxidant with a symmetrical dialkyl or arylalkyl sulphide to obtain an a-ester sulphide compound of the formula RSSCH2OC (O) R' wherein R and R'are as defined above, which compound is further reacted with a sulfinic acid salt to obtain the title compound.

The invention also provides compounds of the general formula RSSCH2OC (O) R', wherein R and R'may be the same or different and each is selected from the group of substituents comprising lower alkyl or phenyl. Preferably, lower alkyl is methyl or ethyl.

The invention also provides a process for making the compounds of the formula defined above, which comprises reacting a transition metal oxidant or a peroxyanhydride oxidant with a symmetrical dialkyl or arylalkyl disulfide to obtain the a-ester disulfide compound.

In yet another aspect of the invention, there is provided a process for preparing a compound of the formula PhS02CH2SSCH3, wherein Ph is phenyl which comprises reacting a transition metal oxidant with dimethyl sulphide to obtain an a-ester sulphide compound of the formula CH3SSCH2OC (O) CH2CH3 which compound is further reacted with the sodium salt of p-toluenesulfinic acid in either aqueous acetonitrile or aqueous acetone to obtain the title compound or the compound is further reacted with potassium p- toluenesulfonate to yield the title compound.

Another aspect of the invention provides a process for preparing compounds of the formula RSO2CHzSSR', wherein R and R'may be the same or different and each is selected from lower alkyl and phenyl, which comprises reacting a transition metal oxidant or a peroxyanhydride oxidant with a symmetrical dialkyl or arylalkyl disulfide to obtain the a- ester disulfide compound RSSCH20C (O) R', wherein R and R'are as defined above, which compound is further reacted with a sulfinic acid salt to obtain the required compound.

Another novel compound is of the formula CISCH2OC. (O) CH2CH3, which is useful as an intermediate.

Another part of the invention comprises antifungal agents comprising as active ingredients a therapeutical effective amount of at least one compound of the formula wherein R'is H or CH3 ; R is CH3, CH2CH3, C6H5, o-CH302C (C6H4), o-CH3SO2 (C6H4), p-CH3SO2 (C6H4), o- NO2 (C6H4), m-NO2 (C6H4), p-NO2 (C6H4), or CH202CCH2CH3 ; and X is SO2 (C6H4) CH3-p, S02CH3, SO2C6H5, SO2CH2CH3, H, O2CCH3, O2CCH2CH3, or CO2CH3 ; and a pharmaceutically acceptable carrier.

Another aspect of the invention provides antifungal agents comprising as active ingredient at least one antifungally active compound of the formulae RSO2CH2SSR1 wherein R is lower alkyl or phenyl and R'is lower alkyl or phenyl, and RC (O) OCH2SSR' wherein R and R'are as defined above optionally together with pharmaceutical acceptable carriers.

In yet another aspect of the invention, there is provided antifungal agents as described above wherein the active ingredient is selected from the group of compounds consisting of o-CH30C (O) (C6H4) SSCH3, [o-CH3SO2 (C6H4) S] 2, [p-CH3SO2 (C6H4) S] 2, m-O2N (C6H4) SSCH3, o-O2N (C6H4) SSCH3, p- O2N (C6H4) SSCH3, p-CH3 (C6H4) SO2CH2 SSCH3, C6H5SO2CH2SSCH3, CH3SO2CH2SSCH3, CH3CH2C (O) OCH2SSCH3, CH3SO2CH2SSPh, CH3SO2CH2SSCH2CH3, CH3SSCH20C (O) CH3, CH3SSCH2OC(O)CH2CH3, CH3SSCH2OC (O) Ph, and PhSSCH20C (O) CH2CH3, optionally together with a pharmaceutical acceptable carrier.

Another aspect of the invention provides an antiproliferative agent active against mammalian cells comprising as active ingredient at least one compound of the formulae RSO2CH2SSR' wherein R is lower alkyl or phenyl and R'is lower alkyl or phenyl, and RC (O) OCH2SSR' wherein R and R'are as defined above, and excluding those compounds disclosed herein that do not exhibit such activity, and optionally together with conventional pharmaceutically acceptable ingredients.

Another aspect of the invention provides an antiproliferative agent active against mammalian cells comprising as active ingredient at least one compound selected from the group of compounds consisting of p-CH3 (C6H4) SO2CH2SSCH3, PhSSPh, <BR> <BR> <BR> <BR> CH3SO2CH2SSPh,<BR> <BR> <BR> <BR> <BR> <BR> CH3SO2CH2CH2SSCH3, CH3SSCH2C (O) OCH3, and CH3SSCH2OC (O) CH3, and optionally together with conventional pharmaceutical acceptable ingredients.

In yet another aspect of the invention, there is provided the use of at least one compound of the formulae RSOzCH2SSR' (I) wherein R is lower alkyl or phenyl and R'is lower alkyl or phenyl, and RC (O) OCH2SSR' (II) wherein R and R'are as defined above, and excluding those compounds disclosed herein that do not exhibit such activity in the preparation of an antifungal agent for the treatment of micoses.

Another aspect of the invention provides the use as described above wherein the agent is for the treatment of aspergillosis.

The invention also provides the use of at least one compound of the formulae RSO2CHzSSR' (I) wherein R is lower alkyl or phenyl and R'is lower alkyl or phenyi, and RC (O) OCH2SSR' (II) wherein R and R'are as defined above, and excluding those compounds disclosed herein that do not exhibit such activity, in the preparation of an antiproliferative agent active against mammalian cells for the treatment of cancer.

In yet another aspect of the invention, there is provided the use of at least one compound selected from the group of compounds as described above in the preparation of a medicament for the treatment of cancer.

DETAILED DESCRIPTION OF THE INVENTION The following correlates the chemical structures and the chemical names of the compounds discussed in this application.

Chemical Structure CH3SO2CH3 CH3SSCH3 CH3SCH2SCH2SCH3 CH3SO2CH2SCH3 CH3SO2CH2SCH2SO2CH3 <BR> <BR> <BR> CH3SCH2SSCH3<BR> <BR> <BR> <BR> <BR> CH3SO2CHzSSPh<BR> <BR> <BR> <BR> <BR> CH3SO2CH2SSCH2CH3 CH3SO2CH2CH2SSCH3 CH3SO2CH2CH2CH2SSCH3 CH3SSCH2C (O) OCH3 CH3SSCH20C (O) CH3 CH3SSCH2CH20C (O) CH3 p-CH3 (C6H4) SO2CH2SSCH3 <BR> <BR> <BR> CeHsSOzCHzSSCHs<BR> <BR> <BR> <BR> CH3SO2CH2SSCH3 p-CH3 (C6H4) SO2CH2SH CH3CH2C (O) OCH2SSCH3 C6H5SSCH3 C6H5SSPh o-CH30C (O) (C6H4) SSCH3 [o-CH3S02 (C6H4) S] 2 [P-CH3S02 (C6H4) S] 2 m-02N (C6H4) SSCH3 o-02N (C6H4) SSCH3 p-O2N (C6H4) SSCH3 p-CH3SO2 (C6H4) OS02CH3 p-O2N (C6H4) OS02CH3 CH3SSCH20C (O) CH3 CH3SSCH20C (O) CH2CH3 CH3SSCH20C (O) Ph PhSSCH20C (O) CH2CH3 (CH30C (O) CH2S) 2 CH30C (O) CH2SSCH20C (O) C2H5 (C2H5C (O) OCH2S) 2 Chemical Name dimethyl sulfone dimethyl sulphide 2, 4, 6-trithiaheptane 2, 4-dithiapentane 2, 2-dioxide 2, 4, 6-trithiaheptane 2, 2, 6, 6-tetraoxide 2, 3, 5-trithiahexane 5-phenyl-2, 4, 5-trithiapentane 2, 2-dioxide 2, 4, 5-trithiaheptane 2, 2,-dioxide 2, 3, 6-trithiaheptane 6, 6,-dioxide 2, 3, 7-trithiaoctane 7, 7-dioxide methyl 3, 4-dithiopentanoate 2, 3-dithiabutyl acetate 3, 4-dithiapentyl acetate a-p-toluenesulfonyl dimethyl disulphide <BR> <BR> <BR> <BR> a-phenylsulfonyl dimethyl disulphide<BR> <BR> <BR> <BR> <BR> α-methylsulfonyl dimethyl disulphide a-p-toluenesulfonyl methyl mercaptan 2, 3-dithiabutyl propionate phenyl methyl disulphide diphenyl disulphide methyl-o (methyldithio) benzoate o-methylsulfonylphenyl sulphide p-methylsulfonylphenyl disulphide methyl m-nitrophenyl disulphide methyl o-nitrophenyl disulphide methyl p-nitrophenyl sulphide p-methylsulfonylphenyl methanesulfonate p-nitrophenyl methanesulfonate 2, 3-dithiabutyl acetate 2, 3-dithiabutyl propionate 2, 3-dithiabutyl benzoate 1-phenyl-1, 2-dithiapropyl propionate dimethyl 3, 4-dithiaadipate methyl 3, 4-dithia-5-propionoxypentanoate 2, 3-dithiabutane-1, 4-dipropionate

C2H50C (O) CH2SSCH2SO2 (C6H4)-p-CH3 1-p-toluenesulfonyl-4-propionoxy-2, 3-dithiabutane (C6H5) C (O) CH2SSCH3 phenacyl methyl disulphide Biological Testing Anti-fungal Activity Sulfur compounds were tested for antifungal activity against pure cultures of Apergillus niger and Aspergillus flavus supplied by Ward's Natural Science Ltd (St. Catharines, Ontario, Canada). They were maintained on Sabouraud Dextrose Agar.

For the test, 6 agar plugs (5 mm diameter) were cut from a 5-8 day old colony and homogenized in distilled, sterilized water (2 ml). A portion of this suspension (0. 5 mi) was transferred aseptically to a Petri plate with Sabouraud Dextrose Agar (15 ml) and spread evenly over the entire surface. Each plate was supplied with four evenly spaced paper disks (7 mm, Whatman Number 1 filter paper) containing the test compound (0, 25, 50 and 100 [ig respectively). Each test compound was applied to the disks as a solution (50 mg compound/10 mi acetone). Control disks were treated with neat acetone (20 jli). Test plates with fungal homogenates and disks were incubated at 18-20°C for 2 days. For each test four replicate plates were used. The diameter of the clear zone surrounding the disk was taken as the indicator of antifungal activity.

Reasonable levels of antifungal activity can be gauged from the result of (CH3SCH2S) 2 which is a known antifungal natural product which shows clear zone diameters of 2. 5 and 2. 3 mm against A. niger and A. flavus, respectively, at a dose of 100 g/disk.

Table 3 Compound Cpd. No. Disk Diameter (mm) of (ig/disk) clear Zone A. niger A. flavus CH3SO2CH3 (2) 100 0 0 CH3SSCH3 (3) 100 0 0 CH3SCH2SCH2SCH3 (4) 100 0 0 CH3SO2CH2SCH3 (5) 100 0 0 CH3SO2CH2SCH2SO2CH3 (6) 100 0 0 CH3SCH2SSCH3 (7) 100 0 0 CH3SO2CH2SSPh (8) 25 0. 8 1. 8 CH3SO2CH2SSCH2CH3 (9) 25 4.8 3.3 CH3SO2CH2CH2SSCH3 (10) 100 0 0 CH3SO2CH2CH2CH2SSCH3 (11) 100 0 0

Table 3 Compound Cpd. No. Disk ! Diameter (mm) of (µg/disk) clear Zone A. niger A. flavus CH3SSCH2C (O) OCH3 (12) 100 0 0 CH3SSCH2OC (O) CH3 (13) 100 2.3 2.3 CH3SSCH2CH2OC(O)CH3 (14) 100 0 0 Compounds (8) and (9) show activity against Aspergillus niger and Aspergillus flavus comparable in magnitude to that reported for Dysoxysulfone (1) against Staphylococcus aureus, Bacillus subtilis and Candida albicans (Block, E., DeOrazio, R., and Thiruvazhi, M., J. Org. Chem., 1994, 59, 2273). It would appear that the inhibition of fungal growth correlates with the presence of both sulfone and sulphide functional groups.

Table 4 Compound Cpd. No. Disk Diameter (mm) of (pg/disk) r clearZone I A. niger A. Flavus p-CH3 (C6H4) SO2CH2SSCH3 (4) 25 10. 9 8. 0 C6HsSO2CH2SSCH3 25 5. 5 4. 2 CH3SO2CH2SSCH3 25 2.7 3.8 p-CH3 (C6H4) SO2CH2SH 100 0 0 CH3CH2C (O) OCH2SSCH3 (2) 25 14. 8 7. 6 Qualitatively, the observed toxicity of the compounds in Table 4 is in complete accord with the earlier proposal (Baerlocher, F. J., Langler, R. F., Frederiksen, M. U., Georges, N.

M., and Witherell, R. D., Aust. J. Chem, 1999, 52, 167) that activated antifungal disulphides (those with a reasonable leaving group attached to the a-carbon) will have pronounced antifungal activity. Quantitatively, the first and last compounds in Table 4 are the most potent fungitoxic disulphides described to date.

Table 5 Compound Cpd. Disk Diameter (mm) of No. (µg/ clear Zone disk) A. niger A. flavus C6H5SSCH3 (4) 100 0 0 C6HsSSPh (5) 100 0 0

Table 5 Compound Cpd. I Disk Diameter (mm) of No. # (µg/ clear zone I disk) A. niger A. flavus o-CH30C (O) (C6H4) SSCH3 (6) 25 2. 8 4. 3 [o-CH3S02 (C6H4) S] 2 (7) 25 3.3 3.0 [p- CH3SO2 (C6H4) S] 2 (8) 25 4.0 6.9 m-O2N (C6H4) SSCH3 (9) 10 1.7 1.8 o-02N (C6H4) SSCH3 (10) 10 2.8 1.9 p-O2N (C6H4) SSCH3 (11) 10 3.9 4.0 p-CH3SO2 (C6H4) OSO2CH3 (12) 100 0 0 p- O2N (C6H4) OSO2CH3 (13) 100 0 0 Toxicity testing against A. niger and A. flavus revealed that (5) is considerably more potent than any other compound disclosed herein. The simple disulphides (4) and (5) are completely inactive against A. niger and A. flavus at a dose of 100 µg/disk.

Table 6 Compound Cpd. No. Disk (µg/ Diameter (mm) of disk) clear Zone A. niger A. flavus CH3SSCH20C (O) CH3 (2) 100 2. 3 2. 3 CH3SSCH2OC (O) CH2CH3 (3) 25 14. 8 7. 6 CH3SSCH2OC (O) Ph (4) 25 6. 1 8. 4 PhSSCH2OC (O) CH2CH3 (5) 2. 5 3. 5 2. 3 Compounds (4) and (5) in Table 6 are novel compounds.

Table 7 Compound Cpd Dose Diameter (mm) of Appl'n No. (pg/disk) Clear Zone Solvent A. niger A. flavus (CH30C (O) CH2S) 2 (1) 100 0 0 Acetone CH30C (O) CH2SSCH20C (O) C2Hs (2) 0. 25 3. 0 2. 3 Acetone (C2HsC (O) OCH2S) 2 (3) 0. 25 3. 6 6. 7 Acetone

Table 7 Compound Cpd Dose Diameter (mm) of Appl'n No. (µg/disk) Clear Zone Solvent A. niger. flavus C2H5OC (O) CH2SSCH2SO2 (C6H4)-p- (4) 0. 25 8. 5 5. 2 Acetone CHIA Amphotericin B 0. 25 4. 2 4. 1 DMSO CH3OC(O)CH2SSCH2OC(O)C2H5 (2) 0.25 11.7 7.9 DMSO (C2H5OC(O)CH2S)2 (1) 0.25 8.0 6.1 DMSO Compounds (2), (3) and (4) of Table 7 are novel compounds. A novel method for preparing compounds (2) and (4) is described in detail in the section entitled"Preparatory Methods". Compound (3) is prepared via a known method and this is detailed in the aforementioned section. Compound (1) is a known compound and the literature contains many references to standaard mathods that can be used to produce it.

Amphotericin B was the most potent of the 3 commercial antifungals tested (included Nystatin and Griseofulvin).

Table 8 Compound Cpd Dose Diameter (mm) of Reference No (µg/ Clear Zone disk) A. niger A. flavus CH3SO2CH2SSCH3 (2) 25 2. 7 3. 8 2 o-CH3SS (C6H4) NO2 (3) 10 2. 8 1. 9 3 CH3SSCH3 (10) 100 0 0 3 CH3SO2SCH3 (11) 100 3. 3 0- CH3CH2SO2SCH3 (5) 50 2. 0 1. 3- (C6H5) SSCH3 12) 100 0 0 3 CH3SO2S (C6H5) (4) * 25 0 3. 7 p-CH3 (C6H4) SO2SCH3 (13) 25 1. 4 3.6 - C6H5 SS (C6H5) (14) 100003 C6H5 SO2S (C6Hs) (15) 25 3. 9 3. 8 p-CH3 (C6H4) SO2S (C6Hs) (16) 25 4. 3 3. 3 o-CH3SS (C6H4) CO2CH3 (17) 25 2. 8 4. 3 3 o-CH3SO2S (C6H4) CO2CH3 (18) 100 0 0 p-CH3SS (C6H4) NO2 (7) 10 3. 8 4. 0 3 p-CH3SO2S (C6H4) NO2 (6) 25 1. 9 1. 2 p-CH3 (C6H4) SO2S C6H4 NO2-p (8 (8) 25 3. 0 2. 0 CH3SSCH2CO2CH3 20) 100 0 0 1 p-CH3 (C6H4) SO2SCH2CO2CH3 (9) 50 2. 9 1. 7 Compound (4) had no measureable fungitoxicity against A. niger at 100 pg/disk.

Thiosulfonates as Antifungal Agents In exploring the development of new, potent antifungal disulphides (Baerlocher, F. J., Langler, R. F., Frederiksen, M. U., Georges, N. M., and Witherell, R. D., Aust. J. Chem., 1999,

52, 167, Langler, R. F., MacQuarrie, S. L., McNamara, R. A., and O'Connor, P. E., Aust. J.

Chem., 52, 1119 (1999), Baerlocher, F. J., Baerlocher, M. O., Langler, R. F., MacQuarrie, S. L., and Marchand, M. E., Aust. J. Chem., 53 1 (2000), and Baerlocher, F. J., Baeriocher, M. O., Chaulk, C. L., Langler, R. F., and O'Brien, E. M., Sulphur Letters-in press, the view that fungitoxicity is likely to be associated with biochemical sulfenylations accomplished by the present disulphides was adopted. Thus, enhancing toxicity has meant making disulphides which are progressively more electrophilic at sulphide sulfur. As an example, phenyl methyl sulphide exerts no observable fungitoxicity at 100 ug/disk (Baerlocher, F. J.. Baerlocher, M. O., Langler, R. F., MacQuarrie, S. L., and Marchand, M. E., Aust. J. Chem., 53 1 (2000)) while o-nitrophenyl methyl disulphide (2) has pronounced toxicity at a dose of 10 ug/disk (see Table 8). Since thiosulfonates are well-known sulfenylating agents for mercaptide anions (see p. 323 of Bere, C. M., and Smiles, S., J. Chem. Soc., 1924, 125, 2361), selected thiosulfonates have been prepared and tested as potential fungitoxins.

Dimethyl sulphide (10) shows no antifungal behaviour, while the two closely related thiosulfonates (5) and (11) have measureable toxicity (vide Table 8). Methyl methanethiosulfonate (11) is the first compound examined which is effective against only one of the test fungi. Note that the enhanced toxicity of (5) is not unexpected since, up to a chain length of nine carbons, longer unbranced alkyl groups are known to enhance pharmacological effects (Silverman, R. B., The Organic Chemistry of Drug Design and Drug Action'p. 16 (Academic Press : San Diego 1992)).

For the series of compounds (4), (12), (13), the sulphide was inactive and the thiosulfonates antifungal. Interestingly, the thiosulfonate (4) killed only A. flavus in contrast to (11) which selectively inhibited the growth of A. niger.

Compounds (14)- (16) also demonstrated the superior antifungal potency of thiosulfonates relative to simple disulphides (see Table 1) but for this set, no selectivity for either of the fungi was observed.

Compound (17) (Table 8) was the first of the potent second-generation antifungal disulphides to be considered here. Perhaps surprisingly, the closely realted thiosulfonate (18) is not antifungal at all. Similar results (diminshed fungitoxicity for the thiosulfonates relative to the disulphide) were obtained for the set of compounds (6), (7), (8). It now appears that thiosulfonates tend to have moderate fungitoxicity-enhanced relative to inactive disulphides and diminished relative to more potent antifungal disulphides. The results in Table 8 open up the possibility that there might be a pharmacological equivalent to the well-known Reactivity Selectivity Principle in organic chemistry (Lowry, T. H., and Richarson, K. S.,'Mechanism and Theory in Organic Chemistry'3rd. Ed., p. 148 (Harper and Row : New York 1987)). The pharmacological equivalent might assert that structural modifications which decrease the potency of a particular agent may be associated with enhanced selectivity in toxicity within a set of closely related organisms.

The interest in antifungal disulphides was encouraged by the recent observations (Pfaller, M., and Wenzell, R., Eur. J. Clin. Microbiol. Infect. Dis. 1992, 11, 287, Debono, M., and Gordee, R. S., Ann. Rev. Microbiol., 1994, 48, 471, and Sternberg, S., Science, 1994, 266, 1632) that fungal infections frequently prove to be lethal for immunocompromised patients. It has recently been learned that (19), a sulphide related to the potent aryl disulphide fungitoxins (e. g. (7) and (17) in Table 8), has been patented for use in inhibiting the production of Interleukin-1 ß and Tumor Necrosis Factor a (Katsuyama, K., Ariga, M., Saito, Y., Hatanaka, S., and Takahashi, T., U. S. Patent 5, 698, 564 (1997)).

Finally, it has been reported earlier, that the a-ester sulphide (20) (see Table 8) had no antifungal activity (Baerlocher, F. J., Langler, R. F., Frederiksen, M. U., Georges, N. M., and Witherell, R. D., Aust. J. Chem., 1999, 52, 167). Nonetheless, when tested, it showed promise as a lead compound in fighting leukemia (Wong, W. W. L., MacDonald, S., Langler, R. F., and Penn, L. Z., Anticancer Research 20 : 1367). The related thiosulfonate (9) shows clearly enhanced antifungal activity.

In terms of currently-available sulfur-rich antifungal compounds, thiosulfonates show intriguing selectivity.

Anti-cancer Activity Summary of Results The following tables group the tested compounds according to their demonstrated activities.

Compounds with No Antiproliferative Activitv A CH3SO2CH3 B CH3SO2CH2SCH2SCH3 G CH3SO2CH2SCH2SO2CH3 J CH3SCH2SCH2SCH3 Compounds with Antiproliferative Activity C CH3 (C6H4) SO2CH2SSCH3 D (C6H5) SS (C6H5) E CH3SO2CH2SS (C6H5) I CH3SSCH20C (O) CH3 K CH3SO2CH2SSCH2CH2CH2CH2CH3 L CH3S02S (C6H5) M p-NO2 (C6H4) SSCH3 N CH3SCH2SSCH3

CH30C (O) CH2SSCH2C (O) OCH3 (C6H5) C (O) CH2SSCH3 (C6H5) SSCH20C (O) CH2CH3 Compounds P and Q are novel compounds. Compound Q is compound (5) in Table 6.

A new method for preparing compound Q is described in detail in the section entitled "Preparatory Methods".

Compounds with Antiproliferative, Tumour-specific Activity F CH3SO2CH2CH2SSCH3 H CH3SSCH2C (O) OCH3 MATERIALS AND METHODS For references pertaining to methods, please refer to Wong, W. W-L., Macdonald, S., Langler, R. F., Penn, L. Z. Anticancer Res 20 : 1367, the disclosures of which are incorporated herein by reference. The number of times each experiment was performed is listed in individual compound data sets.

Cell culture All cell lines were assayed as asynchronously growing cells. Leukemic cell lines, OCI-AML-2, OCI-AML-3 (referred to hereafter as AML-2 and AML-3, respectively), NB- 4, KK, B1, G2, and W1 were cultured in alpha-minimal essential medium (a-MEM) (Princess Margaret Hospital Media Services) supplemented with 10% fetal bovine serum (FBS) (Sigma, St. Louis, MO). Non-transformed, diploid fibroblast lines W138 and IMR90, were cultured in a-MEM and MEM F-15, respectively supplemented with 10% FBS. Media for IMR90 cells was also supplemented with 1. 5 g/L bicarbonate and 1 mM pyruvate. Breast tumour cell lines, MDA-231, SK-BR-3, MCF-7, ZR-751, and melanoma tumour cell lines, WM9, WM983, WM793, 1232, were grown in a-MEM supplemented with 10% fetal bovine serum. Prostate tumour cell lines, DU145 and PC-3, were grown in RPMI 1640 media supplemented with 10% FBS. All cell lines were cultured in the presence of penicillin/streptomycin. Mononucleated cells were isolated from normal bone marrow using Ficoll hypaque and then T-cell depleted. T-cell depletion was performed by incubating the mononucleated bone marrow cells in a- MEM at a concentration of 2 x 107 cells/mL with 10% absor FBS and 10% (v/v) sheep red blood cells for 4 to 16 h. Absor FBS was prepared beforehand by heating FBS at 56°C for 1 h, incubating with sheep red blood cells at 0. 5% (v/v) for 1 h and then filtering the FBS with a 0. 2 M filter. The T-cell depleted, mononucleated cells were recovered using Ficoll hypaque and were maintained in a-MEM supplemented with

20% FBS and 10% 5637 conditioned media. 5637 conditioned media was previously harvested from confluent 5637 cells after a 3 day incubation. Normal bone marrow from bone marrow transplant donor was collected following informed consent according to institutional guidelines.

Organosulfur compound preparation for in vitro testing Approximately 20 mg of each compound was dissolved in 5 mL of ACS grade acetone (Sigma) using a 5 mL volumetric flask. Stock solutions of the compounds were stored in the dark at-20°C. Compounds were diluted prior to each experiment.

MTT Assay Adherent cells were seeded at 67 x 103 cells/mL in a 96 well plate (Falcon, Mississauga, Ontario) the day prior to exposure to compound. Suspension cells were seeded at 27 x 104 cells/mL in a 96 well plate the day of exposure to compound.

Mononucleated, T-cell depleted normal bone marrow cells were seeded at 67 x 104 cells/mL in a 96 well plate the day of exposure to compound. Compounds and solvent control were added to cells and assayed in triplicate or sextuplet. Following 48 h of incubation at 37°C with 5% COz, 40 jlL of a 5 mg/mL solution of 3- [4, 5-dimethylthiazol-2- yl]-2, 5-diphenyltetrazolium bromide (MTT) substrate (Sigma) in Dulbecco's phosphate- buffered saline (D-PBS) was added. After 4 h of incubation at 37°C with 5% CO2, the resulting violet formazan precipitate was solubilized by the addition of 80 iL of a 0. 01 M HCI, 10% sodium dodecyl sulfate (SDS ; Sigma) solution overnight at 37°C with 5% C02.

The plates were then analyzed using the BioRad Benchmark Microplate Reader (BioRad Laboratories, Hercules, California) at 570 nm to determine the optical density of the samples. MTT data was analyzed using Prism 3. 0 (GraphPad Software, Inc., San Diego, California) by the Chou-Talalay method. MTT graphs shown are a representative experiment.

Trypan Blue Exclusion Assay Leukemic cells were seeded in a 24-well plate (Nunc, Naperville, IL) at 25x104 cells/mL. Cells were then exposed in triplicate to solvent control or the approximate MTT50 concentration of compounds B, C, F, G or H at 10 g/mL, or I at 5 ig/mL. The final solvent volume was 2. 4 lL/mL of media for trypan blue exclusion assay. The compound was replenished after 48 h of treatment. Cell counts were evaluated using a 1 : 1 dilution of cell suspension in trypan blue (Gibco-BRL, Mississauga, Ontario, Canada). Viable and nonviable cells were counted using a hemocytometer. Cells which excluded trypan blue were counted as viable whereas stained cells were counted as nonviable. Trypan blue exclusion graphs shown are a representative experiment.

Fixed Propidium lodide (PI) Staining Adherent cell lines were plated at 35 x 104 cells/60 cm2 dish the day before exposure to compound. Suspension cells were seeded at 25 x 104 cells/mL in a 6 well dish (Falcon) the day of exposure to compound. Mononucleated, T-cell depleted normal bone marrow cells were seeded at 50 x 104 cells/mL in a 6 well dish the day of exposure to compound. Cells were exposed to solvent control or approximate MTT50 and MTT30 concentrations of the compound. After 48 h of exposure to the compound, cells were harvested, fixed in 80% ethanol for 1 h on ice and labeled with 50 g/mL propidium iodide (Sigma). Approximately 106 cells were analyzed using a XL-MCL flow cytometer (Coulter Corporation, Miami, Florida) and a FACScalibar cytometer (Becton Dickinson, San Jose, CA). Profiles shown are a representative.

Tdt-mediated dUTP-biotin nick end-labeling (TUNEL) Adherent cell lines were plated at 35 x 104 cells/60 cm2 dish the day before exposure to compound. Suspension cells were seeded at 25 x 104 cells/mL in a 6 well dish (Falcon) the day of exposure to compound. Mononucleated, T-cell depleted normal bone marrow cells were seeded at 50 x 104 cells/mL in a 6 well dish the day of exposure to compound. Cells were exposed to solvent control or approximate MTT50 and MTT30 concentrations of the compound. After 48 h of exposure to the compound, cells were harvested and fixed with a final concentration of 4% formaldehyde. Fixed cells were stored at-20°C in 70% ethanol for no more than 5 days. Approximately 105 cells were pelleted and labeled with 0. 02 mM Biotin-dUTP and 12. 5 U TdT enzyme in a 1x reaction buffer (200 mM potassium cacodylate, 25 mM Tris-HCI, 25 -lg/mL bovine serum albumin, pH 6. 6), 2. 5 mM CoCl2 and 0. 01 mM dTTP (Roche Molecular Biochemicals, Laval, QC, Canada) for 45 min at 37°C. Samples were washed and incubated in 200 L of 1 : 1000 fluorescein isothiocyanate (FITC)-conjugated avidin (Sigma) in 4x SSC, 5% skim milk powder and 0. 05% Tween-20 (Sigma). Following 1 h of mixing at room temperature, the samples were washed and resuspended in 500 L of D-PBS containing 2. 5 g/mL DNase-free RNase (Boehringer Mannheim) and 10 gg/mL PI. Following a 30 min incubation at room temperature, cells were analyzed using a XL-MCL flow cytometer (Coulter Corporation, Miami, Florida) and a FACScalibar cytometer (Becton Dickinson, San Jose, CA). Profiles shown are representative of one experiment.

MATERIALS AND METHODS For references pertaining to methods, please refer to Wong, W. W-L., Macdonald, S., Langler, R. F., Penn, L. Z. Anticancer Res 20 : 1367, the disclosures of which are incorporated herein by reference. The number of times each experiment was performed is listed in individual compound data sets.

Cell culture All cell lines were assayed as asynchronously growing cells. Leukemic cell lines, OCI-AML-2, OCI-AML-3 (referred to hereafter as AML-2 and AML-3, respectively), NB- 4, KK, B1, G2, and W1 were cultured in alpha-minimal essential medium (a-MEM) (Princess Margaret Hospital Media Services) supplemented with 10% fetal bovine serum (FBS) (Sigma, St. Louis, MO). Non-transformed, diploid fibroblast lines W138 and IMR90, were cultured in a-MEM and MEM F-15, respectively supplemented with 10% FBS. Media for IMR90 cells was also supplemented with 1. 5 g/L bicarbonate and 1 mM pyruvate. Breast tumour cell lines, MDA-231, SK-BR-3, MCF-7, ZR-751, and melanoma tumour cell lines, WM9, WM983, WM793, 1232, were grown in a-MEM supplemented with 10% fetal bovine serum. Prostate tumour cell lines, DU145 and PC-3, were grown in RPMI 1640 media supplemented with 10% FBS. All cell lines were cultured in the presence of penicillin/streptomycin. Mononucleated cells were isolated from normal bone marrow using Ficoll hypaque and then T-cell depleted. T-cell depletion was performed by incubating the mononucleated bone marrow cells in a- MEM at a concentration of 2 x 107 cells/mL and supplemented with 10% absor FBS (FBS heated at 56°C for 1 h, incubated with sheep red blood cells at 0. 5% (v/v) for 1 h and then filtered with a 0. 2 iM filter) and 10% sheep red blood cells for 4 to 16 h. The T-cell depleted, mononucleated cells were recovered using Ficoll hypaque and were maintained in a-MEM supplemented with 20% FBS and 10% 5637 conditioned media.

5637 conditioned media was previously harvested from confluent 5637 cells after a 3 day incubation. Normal bone marrow from bone marrow transplant donor was collected following informed consent according to institutional guidelines.

Organosulfur compound preparation for in vitro testing Approximately 20 mg of each compound was dissolved in 5 mL of ACS grade acetone (Sigma) using a 5 mL volumetric flask. Stock solutions of the compounds were stored in the dark at-20°C. Compounds were diluted prior to each experiment.

MTT Assay Adherent cells were seeded at 67 x 103 cells/mL in a 96 well plate (Falcon, Mississauga, Ontario) the day prior to exposure to compound. Suspension cells were seeded at 27 x 104 cells/mL in a 96 well plate the day of exposure to compound.

Mononucleated, T-cell depleted normal bone marrow cells were seeded at 67 x 104 cells/mL in a 96 well plate the day of exposure to compound. Compounds and solvent control were added to cells and assayed in triplicate or sextuplet. Following 48 h of incubation at 37°C with 5% CO2, 40 L of a 5 mg/mL solution of 3- [4, 5-dimethylthiazol-2- yl]-2, 5-diphenyltetrazolium bromide (MTT) substrate (Sigma) in Dulbecco's phosphate- buffered saline (D-PBS) was added. After 4 h of incubation at 37°C with 5% CO2, the resulting violet formazan precipitate was solubilized by the addition of 80 uL of a 0. 01 M

HCI, 10% sodium dodecyl sulfate (SDS ; Sigma) solution overnight at 37°C with 5% CO2.

The plates were then analyzed using the BioRad Benchmark Microplate Reader (BioRad Laboratories, Hercules, California) at 570 nm to determine the optical density of the samples. MTT data was analyzed using Prism 3. 0 (GraphPad Software, Inc., San Diego, California) by the Chou-Talalay method (Chou, TC and Talalay, P : Quantitative analysis of dose-effect relationships : the combined effects of multiple drugs or enzyme inhibitors. Adv Enzyme Reg 22 : 27-55, 1984, Chou, TC. (1991) in Synergism and antagonism in chemotherapy (T. C. Chou and D. C. Rideout, eds.), pp. 61-102, Academic Press, Inc., San Diego). MTT graphs shown are a representative experiment.

Trypan Blue Exclusion Assay Leukemic cells were seeded in a 24-well plate (Nunc, Naperville, IL) at 25x104 cells/mL. Cells were then exposed in triplicate to solvent control or the approximate MTT50 concentration of compounds F (10 g/mL), G (10 pg/mL) or I (5 pg/mL). The final solvent volume was 2. 4 pL/mL of media for trypan blue exclusion assay. The compound was replenished after 48 h of treatment. Cell counts were evaluated using a 1 : 1 dilution of cell suspension in trypan blue (Gibco-BRL, Mississauga, Ontario, Canada). Viable and nonviable cells were counted using a hemocytometer. Cells which excluded trypan blue were counted as viable whereas stained cells were counted as nonviable. Trypan blue exclusion graphs shown are a representative experiment.

Fixed Propidium iodide (PI) Staining Adherent cell lines were plated at 35 x 104 cells/60 cm2 dish the day before exposure to compound. Suspension cells were seeded at 25 x 104 cells/mL in a 6 well dish (Falcon) the day of exposure to compound. Mononucleated, T-cell depleted normal bone marrow cells were seeded at 50 x 104 cells/mL in a 6 well dish the day of exposure to compound. Cells were exposed to solvent control or approximate MTT50 and MTT30 concentrations. After 48 h of exposure to the compound, cells were harvested, fixed in 80% ethanol for 1 h on ice and labeled with 50 pg/mL propidium iodide (Sigma). Approximately 106 cells were analyzed using a XL-MCL flow cytometer (Coulter Corporation, Miami, Florida) and a FACScalibar cytometer (Becton Dickinson, San Jose, CA). Profiles shown are a representative. Cell viability counts and PI staining were performed as previously described (Dimitroulakos, J, Nohynek, D, Backway, KL, Hedley, DW, Yeger, H, Freedman, MH, Minden, MD and Penn, LZ : Increased sensitivity of acute myeloid leukemias to lovastatin-induced apoptosis : A potential therapeutic approach. Blood 93 : 1308-18, 1999).

Tdt-mediated dUTP-biotin nick end-labeling (TUNEL) Adherent cell lines were plated at 35 x 104 cells/60 cm2 dish the day before exposure to compound. Suspension cells were seeded at 25 x 104 cells/mL in a 6 well dish (Falcon) the day of exposure to compound. Mononucleated, T-cell depleted normal bone marrow cells were seeded at 50 x 104 cells/mL in a 6 well dish the day of

exposure to compound. Cells were exposed to solvent control or approximate MTT50 and MTT30 concentrations of compound. After 48 h of exposure to the compound, cells were harvested and fixed with a final concentration of 4% formaldehyde. Fixed cells were stored at-20°C in 70% ethanol for no more than 5 days. Approximately 105 cells were pelleted and labeled with 0. 02 mM Biotin-dUTP and 12. 5 U TdT enzyme in a 1x reaction buffer (200 mM potassium cacodylate, 25 mM Tris-HCI, 25 pg/mL bovine serum albumin, pH 6. 6), 2. 5 mM CoCI2 and 0. 01 mM dTTP (Roche Molecular Biochemicals, Laval, QC, Canada) for 45 min at 37°C. Samples were washed and incubated in 200 jlL of 1 : 1000 fluorescein isothiocyanate (FITC)-conjugated avidin (Sigma) in 4x SSC, 5% skim milk powder and 0. 05% Tween-20 (Sigma). Following 1 h of mixing at room temperature, the samples were washed and resuspended in 500 LL of D-PBS containing 2. 5 lg/mL DNase-free RNase (Boehringer Mannheim) and 10 ig/mL Pl. Following a 30 min incubation at room temperature, cells were analyzed using a XL-MCL flow cytometer (Coulter Corporation, Miami, Florida) and a FACScalibar cytometer (Becton Dickinson, San Jose, CA). Profiles shown are representative of one experiment.

BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings are used to illustrate the invention only and should not be used to limit the scope of the claims. The letter prefix to each of the Table or Figure numbers corresponds to a respective compound. The Tables and Figures have corresponding labels. Thus, Compound A data can be found in Table A-1 which corresponds to Figure A-1. In the accompanying Figures, Figure A-1 illustrates a MTT Assay with Leukemic cell lines, W138 and normal bone marrow ; Figure A-2 illustrates Fixed Propidium iodide Profiles ; Figure B-1 illustrates a MTT Assay with Leukemic cell lines, W138 and normal bone marrow ; Figure B-2 illustrates Trypan Blue Exclusion Assay ; Figure B-3 illustrates Fixed Propidium iodide Profiles ; Figure B-4 illustrates TUNEL Profiles ; Figure C-1 illustrates a MTT Assay with Leukemic cell lines, W138 and normal bone marrow ; Figure C-2 illustrates a Trypan Blue Exclusion Assay ; Figure C-3 illustrates Fixed Propidium lodide Profiles ; Figure C-4 illustrates TUNEL Profiles ; Figure D-1 illustrates a MTT Assay with Leukemic cell lines, W138 and normaJ bone marrow ; Figure D-2 illustrates Fixed Propidium lodide Profiles ;

Figure E-1 illustrates a MTT Assay with Leukemic cell lines, W138 and normal bone marrow ; Figure E-2 illustrates Fixed Propidium lodide Profiles ; Figure F-1 illustrates a MTT Assay with Leukemic cell lines, W ! 38 and normal bone marrow ; Figure F-2 illustrates a Trypan Blue Exclusion Assay ; Figure F-3 illustrates Fixed Propidium iodide Profiles ; Figure F-4 illustrates TUNEL Profiles ; Figure G-1 illustrates a MTT Assay with Leukemic cell lines, W138 and normal bone marrow ; Figure G-2 illustrates a Trypan Blue Exclusion Assay ; Figure G-3 illustrates Fixed Propidium iodide Profiles ; Figure G-4 illustrates TUNEL Profiles ; Figure H-1 illustrates a MTT Assay with Leukemic cell lines, W 138 and normal bone marrow ; Figure H-2 illustrates a Trypan Blue Exclusion Assay ; Figure H-3 illustrates Fixed Propidium iodide Profiles ; Figure H-4 illustrates TUNEL Profiles ; Figure 1-1 illustrates a MTT Assay with Leukemic cell lines, W138 and normal bone marrow ; Figure 1-2 illustrates a Trypan Blue Exclusion Assay ; Figure 1-3 illustrates Fixed Propidium iodide Profiles ; Figure 1-4 illustrates TUNEL Profiles ; Figure J-1 illustrates a MTT Assay with Leukemic cell lines, W138 and normal bone marrow ; Figure J-2 illustrates Fixed Propidium iodide Profiles ; Figure K-1 illustrates a MTT Assay ; Figure K-2 illustrates a MTT Assay with Normal Bone Marrow ; Figure L-1 illustrates a MTT Assay ; Figure L-2 illustrates a MTT Assay with Normal Bone Marrow ; Figure M-1 illustrates a MTT Assay ; Figure M-2 illustrates a MTT Assay with Normal Bone Marrow ; Figure M-3 illustrates Fixed Propidium iodide Profiles ; Figure N-1 illustrates a MTT Assay ; Figure N-2 illustrates a MTT Assay with Normal Bone Marrow ; Figure N-3 illustrates Fixed Propidium iodide Profiles ; Figure N-4 illustrates TUNEL Profiles ; Figure 0-1 illustrates a MTT Assay ; Figure 0-2 illustrates a MTT Assay with Normal Bone Marrow ;

Figure P-1 illustrates a MTT Assay ; Figure P-2 illustrates a MTT Assay with Normal Bone Marrow ; Figure P-3 illustrates Fixed Propidium iodide Profiles ; Figure P-4 illustrates TUNEL Profiles ; Figure Q-1 illustrates a MTT Assay ; Figure Q-2 illustrates a MTT Assay with Normal Bone Marrow ; Figure Q-3 illustrates a MTT Assay with Breast/Prostate/Melanoma cell lines ; Figure Q-4 illustrates Fixed Propidium iodide Profiles ; Figure Q-5 illustrates TUNEL Profiles.

Table A-1 Cell line MTT50 I Number of uM ! Experiments Leukemic I # AML-3 > 265 (25 ug/mL) 6 KK>265 (25ug/mL) 6 Normal # WI38 > 265 (25 ug/mL) 6 . Normal bone marrow > 265 (25 ug/mL) 3 Table A-2 Cell line Flow Cytometry Number of Fixed Pi Experiments Dose (uM) % pre-G1 Acetone ctrl % re-G1 Leukemic . AML-3 212 (20 ug/mL) 0. 1 0. 8 3 KK212 (20ug/mL) 1. 13. 43 Notes : No anti-proliferative properties Table B-1 Cell line MTT50 Number of uM Experiments Leukemic . AML-3 > KK >134 (25 ug/mL) 6 Normal . WI38 >134 (25 ug/mL) 6 # Normal bone marrow >134 (25 ug/mL) 3 Table B-2 Trypan Blue Exclusion Assays n=3

Table B-3 Cell line Flow Cytometry Number of Fixed PI Experiments Dose % pre-% Acetone ctrl (uM) G2/M G1 % pre-G1 % G2/M Leukemic . AML-3 107 (20 0. 3 13. 4 0. 3 13. 9 3 ug/mL) . KK 107 (20 1. 1 3. 4 3 ug/mL) Table B-4 Cell line Flow Cytometr Number of TUNEL Experiments Dose (uM) TUNEL Acetone FITC +ve TUNEL FITC +ve Leukemic . AML-3 107 (20 3. 85 3. 1 2 ug/mL Notes : No anti-proliferative activity Table C-1 Cell line MTT50 Number of uM Experiments Leukemic # AML-2 13. 2 2 . AML-3 16. 9 6 . NB-4 11. 7 2 # KK 31. 4 6 . B1 13. 0 2 . W1 8.7 2 Normal # WI38 89.0 6 # Normal bone marrow 20.9 3 Table C-2 Cell line Flow Cytometry Number of Fixed PI Experiments Dose % pre-% Acetone ctri (uM) G2/M G1 % pre-G1 % G2/M Leukemic AML-3 20. 2 (10 10. 7 11. 1 0. 3. 13. 9 3 ug/mL # KK 40. 3 (20 20. 6 3. 4 3 ug/mL)

Table C-3 Cell line Flow Cytometr Number of TUNEL Experiments Dose (uM) I TUNEL Acetone FITC +ve TUNEL FITC +ve Leukemic . AML-3 20. 2 (10 22. 4 3. 1 2 ug/mL) Notes : Anti-proliferative activity Table D-1 Cell line MTT50 Number of uM Experiments Leukemic . AML-3 16 . KK 12.8 6 Normal . WI38 45.3 6 # Normal bone marrow 19.1 3 Table D-2 Cell line Flow Cytometr Number of Fixed PI Experiments Dose (uM) % pre-G1 Acetone ctr@ %pre-G1 Leukemic . AML-3 91. 6 (20 ug/mL) 24. 1 0. 8 3 . KK 91. 6 (20 ug/mL) 33. 9 3. 4 3 Notes : Anti-proliferative activity Table E-1 Cell line MTT50 Number of uM Experiments Leukemic # AML-2 15.6 2 AML-3 15.4 6 NB-4 25. 4 2 . KK 17. 5 6 # B1 4. 3 2 # G2 3. 6 2 Normal # 0 W138 45.2 6 * Normal bone marrow 21.9 3

Table E-2 Cell line Flow Cytometry I Number of Fixed Pi Experiments Dose (uM) % pre-G1 Acetone ctrl % re-G1 Leukemic . AML-3 85. 3 (20 ug/mL) 24.5 0.8 3 . KK 85. 3 (20 ug/mL) 34.7 3.4 3 Notes : Anti-proliferative activity Table F-1 Cell line MTT50 Number of i uM Experiments Leukemic . AML-2 37. 6 2 . AML-3 44. 0 6 . KK 93.4 6 Normal . W138 I > 100 (25ug/mL) 6 . Normal bone marrow 1 115. 8 3 Table F-2 Trypan Blue Exclusion Assays n=3 Table F-3 Cell line Flow Cytometry Number of Fixed Pi Experiments Dose % pre-% Acetone ctrl (uM) G2/M G1 % pre-G1 % G2/M Leukemic . AML-3 45. 8 (10 5. 1 34. 1 0. 3 13. 9 3 ug/mL . KK 91. 6 (20 3. 8 3. 4 3 ug/mL) Normal # WI38 50 (229 0. 1 17. 8 0. 1 14. 0 2 ug/mL Table F-4 Cell line Flow C omet Number of TUNEL Experiments Dose (uM) TUNEL'Acetone FITC +ve TUNEL FITC +ve Leukemic 'AML-3 45. 8 (10ug/mL) 31. 93. 1 1 2

Notes : Anti-proliferative activity Table G-1 Cell line MTT50 Number of uM Experiments Leukemic . AML-3 114 (>25 ug/mL) 6 . KK 114 (>25 ug/mL) 6 Normal # WI38 114 (>25 ug/mL) 6 # Normal bone marrow 114 (>25 ug/mL) 3 Table G-2 Trypan Blue Exclusion Assays n=3 Table G-3 Cell line Flow Cytometry Number of Fixed Pi Experiments Dose % pre-% Acetone ctrl (uM) G2/M G1 % pre-G1 % % ! G2/M Leukemic AML-3 45. 8 (10 0. 3 13. 5 0. 3 13. 9 3 ug/mL) . KK 91. 6 (20 3. 8 3. 4 3 ug/mL) Table G-4 Cell line Flow Cytometry Number of TUNEL Experiments Dose (uM) TUNEL Acetone FITC +ve TUNEL FITC +ve Leukemic 'AML-3 45. 8 (10 3. 0 3. 1 2 ug/mL) Notes : No anti-proliferative activity Table H-1 Cell line MTT50 Number of uM Experiments Leukemic # AML-3 93.4 6 # KK 110.4 6 Normal . W138 > 164 (25 ug/mL) 6 * Normal bone marrow 366.2 3

Table H-2 Trypan Blue Exclusion Assays n=3 Table H-3 Cell line Flow Cytometry Number of Fixed Pi Experiments Dose (uM) % pre-G1 Acetone ctrl % pre-G1 Leukemic . AML-3 65. 7 (10 ug/mL) 3. 6 0.3 3 . KK 133. 4 (20 5. 9 3. 4 3 ug/mL) Normal # WI38 985 (150 ug/mL) 0. 7 0. 1 2 Table H-4 Cell line Flow Cytometry Number of TUNEL Experiments Dose (uM) TUNEL Acetone FITC +ve TUNEL FITC +ve Leukemic # AML-3 65.7 910 ug/mL) 10.2 3.1 2 Notes : Anti-proliferative activity Table I-1 Cell line MTT50 Number of uM Experiments Leukemic . AML-3 31. 5 6 . KK 31. 5 6 Normal . WI38 76.9 6 * Normal bone marrow 32. 8 3 Table l-2 Trypan Blue Exclusion Assays n=3 Table 1-3 Cell line Flow Cytometry Number of Fixed PI Experiments Dose (uM) % pre-G1 Acetone ctrl % % pre-G1 Leukemic # AML-3 32. 8 (5 ug/mL) 23.6 0.3 3 . KK65. 7 (10ug/mL) 48. 43. 43

Table 1-4 Cell ine How Cytometry Number of TUNEL Experiments Dose (uM) TUNEL Acetone FITC +ve TUNEL FITC +ve Leukemic # AML-3 32. 8 (5 ug/mL) 57. 3 3.1 2 Notes : Anti-proliferative activity Table J-1 Cell line MTT50 Number of uM Experiments Leukemic # AML-3 > 162 (25 ug/mL) 6 # KK > 162 (25 ug/mL) 6 Normal # WI38 > 162 (25 ug/mL) 6 # Normal bone marrow > 162 925 ug/mL) 3 Table J-2 Cell line Flow Cytometr Number of Fixed PI Experiments Dose (uM) % pre-G1 Acetone ctrl % pre-G1 Leukemic # AML-3 129. 6 (ug/mL) 0. 20. 33 # KK129. 6 (ug/mL) 2. 63. 43 Notes : No anti-proliferative activity Table K-1 Cell line MTT50 (uM) Number of repeats Leukemic # B1 6. 07 # G2 6.61 4 KK 6. 6 # NB-4 6. 36 # AML-3 4. 6 Normal WI38 19. 01 4

Table K-2 Cell line MTT50 Number of (uM) repeats Leukemic # G2 I 5. 8 1 # NB-4 7.8 ---7 Normal # Normal bone 22. 04 marrow Table L-1 Cell line MTT50 Number of (uM) Repeats Leukemic # B1 6.34 # W1 7. 26 # G2 3. 8 # KK 6. 3 # NB-4 15. 09 # AML-3 7.46 Normal # WI38 19.69 Table L-2 Cell Number of (uM) Repeats Leukemic NB-432. 64 Normal # W138 7. 9 Normal bone 44. 21 marrow

Table M-1 Cell line MTT50 Number of Repeats (uM) Leukemic # B1 12. 73 # W1 4.8 6 G2 11. 28 # KK 10. 48 # NB-4 21. 23 # AML-3 15. 03 Normal # W138 13. 85 Table M-2 Cell line MTT50 Number of Repeats (uM) Leukemic 2 # AML-3 8. 53 Normal # WI38 17. 45 Normal bone 22. 61 marrow z Table M-3 Cell line Flow Cytometry Fixed PI Dose (uM) % pre-G1 Acetone ctr@ % re-G 1 Leukemic B1 20 70 2 40 76 W1 20 9 0. 3 40 28 G2 20 10 1 40 43 NB-4 20 16 6 40 60 AML-3 20 34 1 40 56 Normal # WI38 20 19 0. 2 40 16 Table N-1 Cell line MTT50 Number of Repeats (uM) Leukemic # B1 94. 39 # KK 65.24 6 # N B-4 60. 78 # AML-3 51. 08 Normal # WI38 >100 Table N-2 Cell line MTT50 Number of (uM) Repeats Leukemic 1 # AML-3 73. 36 Normal # W138 >100 Normal bone >100 marrow Table N-3 Cell line Flow Cytometry Fixed PI Dose (uM) % pre-G1 Acetone ctrl % G2 % re-G1 increase Leukemic 1 B1 50 17 2 +2 150 35-1 . W150227+10 150 33 G2 50 16 2 +8 150 29 +8 KK 50 13 7 +4 150 10 +5 . AML-3 50 17 2 +17 150 35 +14 Normal # WI38 50 2 1 +7 150 4 +25

Table N-4 Cell line Flow Cytometry TUNEL Dose (uM) % TUNEL Acetone ctrl +ve (% TUNEL +vue) Leukemic # B1 50 49 1 100 44 # G2 50 18 2 100 19 # NB-4 50 17 8 100 19 Normal # WI38 50 0.7 0. 2 100 2 Table 0-1 Cell line MTT50 Number of Repeats (uM) Leukemic # B1 57. 43 # KK 96. 9 4 # NB-4 62. 89 # AML-3 55. 75 Normal # W138 173. 87 Table 0-2 Cell line MTT50 I Number of Repeats (uM) (%) Leukemic # AML-3 44. 09 1 Normal Normal Bone >100 Marrow

Table P-1 Cell line MTT50 Number of Repeats (uM) Leukemic # B1 94. 38 ka 65. 24 # NB-4 60. 78 6 # AML-3 51. 08 Normal # WI38 >100 Table P-2 Cell line MTT50 Number of Repeats (uM) Normal # W138 >100 # Normal bone >100 marrow Table P-3 Cell line Flow Cytometry Fixed PI Dose (uM) % pre-G1 Acetone ctrl % re-G1 Leukemic B1 50 52 2 150 80 W1 50 14 0. 3 150 55 G2 50 6 1 150 63 NB-4 50 18 6 150 75 AML-3 50 7 1 150 66 Normal # WI38 50 2 0. 2 150 52

Table P-4 Cell line Flow Cytometry TUNEL Dose (uM) % TUNEL Acetone ctrl +ve (% TUNEL +ve) Leukemic B1 50 39 1 100 67 # G2 50 17 2 100 53 # KK 50 47 1 100 78 # NB-4 50 24 8 100 0. 2 Normal # WI38 50 0.70 0. 2 100 1. 7 Table Q-1 Cell line MTT50 Number of repeats (uM) Leukemic . B1 14. 28 . W1 13. 03 # G2 14.68 6 . KK 23. 69 . AML-3 22. 5 Normal # W138 >100 I Table Q-2 Cell line MTT50 Number of (uM) repeats Normal # W138 >100 1 Normal bone >100 marrow Table Q-3 Cell line MTT50 Number of repeats (uM) Normal # WI38 >100 1 Breast MDA-231 68. 87 SK-BR-3 59 ZR-751 52 Prostate # DU145 65. 43 1 Melanoma # WM9 41 WM983 46. 98 1 WM793 47 1232 56 Table Q-4 Cell line Flow Cytometry Fixed Pi Dose (uM) % pre-G1 Acetone ctr@ % G2 % pre-G1increase Leukemic # B1 20 5 2 0 40 20 -3 # W1 20 20 7 +4 40 49 +12 # G2 20 31 2 -1 40 55-3 # KK 20 15 7 40 43-4 . AML-3 20 10 2-5 40 42-9 Normal # WI38 20 1 1 +3 40 1 +10

Table Q-5 Cell line Flow Cytometry TUNEL ! Dose (uM) % TUNEL i Acetone ctrl +ve (% TUNEL +ve) Leukemic Bl B1 25 32 1 50 78 G2 25 23 2 50 58 KK 25 43 1 50 61 NB-450168 l l I Normal W138 25 4 0. 2 i 50 0. 2 ! DISCUSSION Initially, the efficacy of ten synthetic OSCs was explored for their antiproliferative activity against mammalian cells. This was expanded to include seven more compounds.

On the basis of activity (MTT assays) the OSCs were separable into three distinct groups ; Group I (compounds A, B, G, J), Group II (compounds F, H) and Group III (compounds C, D, E, l). The trypan blue exclusion results, in combination with the MTT activity results indicate that compounds C, D, E, F, H and I were cytotoxic to the leukemic cells in a dose- dependent manner. Exposure to compounds F and H led to an accumulation of leukemic cells in the G2/M phase of the cell cycle prior to the cells undergoing apoptosis. By contrast, compounds C, D, E and I trigger the leukemic cells to undergo apoptosis in all the phases of the cell cycle as determined by fixed PI and TUNEL. Interestingly, the viability of non-transformed human W138 fibroblasts was not affected following exposure to compounds A, B, G, J, F and H yet decreased in response to compounds C, D, E and 1.

The common structural feature of all the active antileukemic OSCs analyzed in this study was the presence of a disulphide. Indeed, many biologically active natural products of the genus allium are disulphides or closely related thiosulfinates or thiosulfonates (Block, E : The organosulfur chemistry of the genus Allium-implications for the organic chemistry of sulfur. Angew. Chem. Int. Ed. Engl. 31 : 1135-1178, 1992). Clearly in this study, however, the sulfone sulphide F and disuiphide ester H exhibit specificity towards transformed cell lines.

A handful of investigators have explored the effects of naturally-occurring OSCs, such as S-allylmercaptocysteine (SAMC) or diallyl disulphide (DADS) on the growth of tumor cell lines. Sigounas et al. (Sigounas, G, Hooker, JL, Li, W, Anagnostou, A and Steiner, M : S- allylmercaptocysteine, a stable thioallyl compound, induces apoptosis in erythroleukemia cell lines. Nutr Cancer 28 : 153-9, 1997, Sigounas, G, Hooker, J, Anagnostou, A and Steiner, M : S-allylmercaptocysteine inhibits cell proliferation and reduces the viability of

erythroleukemia, breast, and prostate cancer cell lines. Nutr Cancer 27 : 186-91, 1997) have shown that SAMC reduces viability of erythroleukemia, breast and prostate cancer cell lines. The effects of compounds F and H appear to be similar to SAMC and DADS.

Both SAMC and DADS have been shown to growth arrest cells in the G2/M phase of the cell cycle prior to apoptosis in a time and dose dependent manner (Sigounas, G, Hooker, JL, Li, W, Anagnostou, A and Steiner, M : S-allylmercaptocysteine, a stable thioallyl compound, induces apoptosis in erythroleukemia cell lines. Nutr Cancer 28 : 153-9, 1997, Sundaram, SG and Milner, JA : Diallyl disulphide inhibits the proliferation of human tumor cells in culture. Biochim Biophys Acta 1315 : 15-20, 1996, Sundaram, SG and Milner, JA : Diallyl disulphide induces apoptosis of human colon tumor cells. Carcinogenesis 17 : 669- 73, 1996, Knowles, LM and Milner, JA : Depressed p34cdc2 kinase activity and G2/M phase arrest induced by diallyl disulphide in HCT-15 cells. Nutr Cancer 30 : 169-74, 1998).

However, unlike compound F and H, SAMC does not appear to be tumor-specific as it has been shown to inhibit proliferation of non-transformed cells (Sigounas, G, Hooker, JL, Li, W, Anagnostou, A and Steiner, M : S-allylmercaptocysteine, a stable thioallyl compound, induces apoptosis in erythroleukemia cell lines. Nutr Cancer 28 : 153-9, 1997). Compared to these natural compounds, Group II and Group III OSCs in this study were approximately 2 and 10 fold more potent, respectively, suggesting the specific activity of natural OSCs can be increased by structure-activity analysis of synthetic derivatives. it appears that the structural criteria of OSCs for their antifungal and antitumor activities are separable and distinct. Comparison of the antifungal (Baerlocher, FJ, Langler, RF, Frederiksen, MU, Georges, NM and Witherell, RD : Structure-activity relationships for selected sulfur-rich antifungal compounds. Aust. J. Chem. 52 : 167-172, 1999) and antileukemic activity of the synthetic OSCs reveals compounds A, B, G and J do not possess antiproliferative activity on either fungal or mammalian cells. By contrast, compounds C, E and I possess antifungal and anti-mammalian cell activity, which is consistent with the notion that disulphides are general toxins (Rice, WG, Turpin, JA, Schaeffer, CA, Graham, L, Clanton, D, Buckheit, RW, Jr., Zaharevitz, D, Summers, MF, Wallqvist, A and Covell, DG : Evaluation of selected chemotypes in coupled cellular and molecular target-based screens identifies novel HIV-1 zinc finger inhibitors. J Med Chem 39 : 3606-16, 1996). Finally, compounds D, F and H do not possess antifungal activity but can inhibit mammalian cell growth. Moreover, compound F and H are distinct from compound D as these compounds possess tumor-specific activity. Unlike other natural products currently being explored as therapeutics, these compounds are relatively simple and inexpensive to synthesize. The discussion under the heading"Summary of Results" describes these results as well as the results for compounds K to Q.

Preparatory Methods The methods described herein encompass both novel and known methods of preparation. The preparation of novel compound 4 in Table 6 represents a novel method.

Compound Q is a novel compound and its method of preparation is also novel. The method for preparing compound 2 in Table 7 is new, but compound 3 is made by a known method. The same is true for compound 4 of Table 7 and for compound P. The following description provides an overview of various aspects of the methods described herein. It is believed that the person skilled in the art could readily apply the various methods for preparing the compounds of this invention to produce additional compounds having the same basic structure. The additional detail found in the specific methods described provides instruction for the detail of such methods. This is particularly true for any group of compounds or specific compound mentioned herein, the preparation for which is not described.

From the beginning of this program to make biologically active organosulfur compounds, a-substituted disulphides have been targeted for synthesis. Initially, singly a-substituted dimethyl disulphides i. e. 1 were chosen for construction.

CH3SSCH2W 1 A) Conditions for disproportionations in dimethyl sulphide which afford unsymmetrical methyl disulphides smoothly have been optimized. This chemistry affords methyl disulphides even when reactions proceed through the metastable intermediates : RSCH2S- (see eq. [1] for an example).

B) Well-known, base-catalyzed condensations of sulfenyl chlorides and mercaptans have been exploited for the construction of unsymmetrical disulphides. Symmetrical disulphides have traditionally been used to make sulfenyl chlorides, so that only one sulfenyl chloride is produced (see eq. [2]).

In a number of cases, symmetrical disulphides (e. g. (p-O2N (C6H4) S) 2 or (CH30C (O) CH2S) 2) will not react with our chlorinating agent. It has now been established that the corresponding methyl disulphides cleave smoothly with SO2Ci2/CH2CI2 (see eq. [3] for an example).

Methanesulfenyl chloride is very volatile and is completely removed when the solvent is evaporated. Hence, we have established that unsymmetrical methyl disulphides are useful precursors for the preparation of homogeneous sulfenyl chlorides.

C) Now described are new transition metal oxidations of dialkyl disulphides which furnish, the virtually unknown a-ester disulphides in which the ester group is attached to the sulphide framework by an oxygen atom (see eq. [4] for an example).

These a-ester disulphides show, inter alia, antifungal and antileukemic properties.

D) It has been established that a-ester disulphides serve as effective precursors for the preparation of a-sulfonyl disulphides which also show antifungal and antileukemic properties (see eq. [5] for an example).

E) In a powerful conjunction of B) and D), the sulfenyl chloride ester 2 has been prepared.

CISCH20C (O) C2H5 2 This versatile intermediate permits nucleophilic attack at both S and at C. It is a synthetic equivalent for 3.

+S-CH2 3 3 permits general access to unsymmetrical disulphides, through a-ester disulphides (see eq. [6]).

Infrared spectra were recorded on a Perkin-Elmer 71 OB grating spectrophotometer for chloroform solutions unless otherwise specified.'H n. m. r. spectra (60 MHz) were obtained

on a Varian EM360L instrument.'H n. m. r. (270 MHz) and 13C n. m. r. spectra were obtained on a JEOL JNM-GSX 270 Fourier-transform n. m. r. system. Unless otherwise specified, all n. m. r. spectra were obtained for (D) chloroform solutions with tetramethylsilane as internal standard. Mass spectra were obtained on a Hewlett-Packard 5988A g. l. c./m. s. system. Melting points were determined on a Gallenkamp MFB-595 capillary melting point apparatus and are uncorrected.

Preparation of Compounds of Table 3 Previously Prepared Compounds Compounds (4) and (6) were prepared as described in Ahern, T. P., Hennigar,. T. L., MacDona/d, J. A., Morrison, H. G., Langler, R. F., Satyanarayana, S., and Zawarotko, M.

J., Aust. J. Chem., 1997, 50, 683 and compound (8) was prepared as described in Ahern, T. P., Langler, R. F., and McNeil, R. L., Can. J. Chem., 1980, 58, 1996. Compound (13) was prepared as described earlier (Georges, N. M. Johnson, M. D., Langler, R. F., and Verma, S. D., SulfurLett. 22, 141 (1999). Compounds (5) (Robson, P., Speakman, P. H.

R., and Stewart, D. G., J. Chem. Soc. C, 1968, 2180, Bohme, H., and Heller, P., Chem.

Ber., 1953, 86, 785) and (7) (Dubs, P., and Stuessi, R., Helv. Chim. Acta, 1978, 61, 2351) have been prepared by earlier workers.

Preparation of 2, 4-Díthiapentane 2, 2-Dioxide (5) (A) A solution of 2, 4-dithiapentane (0. 98 g, 9. 0 mmol) and hydrogen peroxide (1. 03 g, 30%) in 1, 4-dioxan (24 ml) was refluxed behind a safety shield for 0. 5 h and the solvent evaporated.

(B) Potassium permanganate (0. 74 g, 4. 7 mmol) was covered with water (4. 2 ml) and tetrahydrofuran (17 ml). Crude product from part (A) was dissolved in water (7 ml) and tetrahydrofuran (28 ml) and added to the reaction mixture. The reaction mixture was stirred at ambient temperature for 1 h and filtered through a Celite filter pad. The filtered solution was added to solid sodium thiosulfate (35 g) and the mixture stirred for 0. 5 h.

The solid was filtered off and the organic solvent evaporated affording a wet residue. The residue was extracted with chloroform (three 100 ml aliquot). The organic layers were combined, dried (MgS04), filtered and concentrated. The crude product was chromatographed on silica gel (70 g) employing chloroform elution (50 ml fractions).

Fractions 14-16 were combined and concentrated affording clean 2, 4-dithiapentane 2, 2-dioxide (5) (0. 13 g, 0. 9 mmol, 10%) as an oil. I. r. 1310, 1160 cm-'.'H n. m. r. (60 MHz) 6 2. 43, s, 3H ; 3. 06, s, 3H ; 3-85, s, 2H. m/z 140 (9%, M"), 61 (100).

Preparation of 2, 3, 5-Trithiahexane (7) Sodium metal (0. 163 g, 7. 0 mmol) was dissolved in methanol (10 ml), the solvent evaporated and the sodium methoxide dried in vacuum. Dimethyl sulfoxide (Me2SO) (3 ml) was added and the resultant suspension stirred vigorously for 5 h.

Dimethyl disulphide (3. 7 g, 38. 8 mmol), 3, 5-dithiahexan-2one (Ahern, T. P., Haley, M.

F., Langler, R. F. and Trenholm, J. E. Can. J. Chem., 1984, 62, 610) (1. 0 g, 7. 7 mmol)

and Me2SO (2 ml) were added. The reaction mixture was stirred at ambient temperature for 2 days. Hydrochloric acid (2. 5%, 100 ml) was added and the resultant mixture extracted with diethyl ether (three 100 ml aliquots). The combined organic layers were concentrated and the extraction procedure was repeated. The combined organic layers were dried (MgS04) and filtered, and the solvent was evaporated.

The crude product was chromatographed on silica gel (10 g) employing light petroleum (10 ml fractions) for elution. Fractions 3-7 were combined and the residue was distilled furnishing 2, 3, 5-trithiahexane (7) (0. 45 g, 3. 2 mmol, 42%), b. p. 106°C/18 Torr.'H n. m. r. (270 MHz) 5 2. 23, s, 3H ; 2. 50, s, 3H ; 3. 85, s, 2H.'3C n. m. r. 8 15-15, 23. 42, 44. 22. m/z 140 (26%, M'), 61 (100).

Preparation of 2, 4, 5-Trithiaheptane 2, 2-Dioxide (9) Ethanethiol (1. 4 g, 22. 4 mmol) was dissolved in dry pyridine (50 ml) and CH3SO2CC12SOCH3 (Ahern, T. P., Langler, R. F., and McNeil, R. L., Can. J.

Chem., 1980 58, 1996) (1. 2 g, 4. 5 mmol) added. The reaction mixture was stirred at ambient temperature for 24 h. Chloroform (200 ml) was added and the resultant mixture washed with 5% hydrochloric acid (100 ml aliquots) until the aqueous layer remained acidic. The organic layer was dried (MgS04), filtered and concentrated. The residue was chromatographed on silica gel (150 g) employing chloroform elution (100 ml fractions). Fractions 8-11 were combined and concentrated affording clean sulfone sulphide (9) (0. 45 g, 2. 4 mmol, 53%).

Recrystallized 2, 4, 5-trithiaheptane 2, 2-dioxide (methanol) had m. p. 34. 6-36. 3°C (Found : C, 25. 6 ; H, 5. 4. C4H002S3 requires C, 25. 8 ; H 5. 4%). I. r. 1325, 1150 cm-'.'H n. m. r. (270 MHz) 8 1. 37, t, 3H ; 2. 91, q, 2H ; 3. 04, s, 3H ; 4. 09, s, 2H.'3C n. m. r. 5 14-17, 33. 31, 39. 21, 62. 40. m/z 186 (13%, M*'), 107 (67), 79 (100).

Preparation of 3, 6-Dithiaheptan-2-one Thioacetic S-acid (49. 8 g, 655 mmol) and 4-chloro-2-thiabutane (Fong, H. O., Hardstaff, W. R., Kay, D. G., Langler, R. F., Morse, R. G., and Sandoval, D. N., Can. J.

Chem., 1979, 57, 1206) (40. 0 g, 363 mmol) were added to dry pyridine (550 mi), and the reaction mixture was refluxed for 2 h. Dichloromethane (2. 7 litres) was added and the resultant mixture extracted with 5% hydrochloric acid (600 mi portions) until the aqueous layer remained acidic. The organic layer was dried (MgS04), filtered and the solvent distilled off at atmospheric pressure. The residue was rectified at reduced pressure affording 3, 6-dithiaheptan-2-one (32. 1 g, 214 mmol, 59%), b. p. 80°C/43 Torr. I. r. (liquid film) 1690 cm''.'H n. m. r. (270MHz) 62. 17, s, 3H ; 2. 35, s, 3H ; 2. 67, t, 2H ; 3. 10, t, 2H.'3C n. m. r. 6 15. 37, 28. 72, 30. 65, 33. 86. m/z 150 (9%, M'), 74 (55), 61 (40), 43 (100).

Preparation of 3-Thiabutane-l-thiol 3, 6-Dithiaheptan-2-one (32. 1 g, 214 mmol) was dissolved in methanol (900 ml) and sodium hydroxide (11. 1 g, 277 mmol) in water (500 mi) added. The reaction mixture was stirred at ambient temperature for 1 h. Water (1 litre) and 10% hydrochloric acid (400 ml)

were added. The resultant mixture was extracted with methylene chloride (five 800 ml aliquot). The bulk of the solvent was distilled off at atmospheric pressure. The residue was dissolved in methylene chloride (500 mi) and the resultant solution washed with 5% sodium hydroxide solution (three 200 mi portions). The aqueous layer was strongly acidified (concentrated hydrochloric acid) and extracted with dichloromethane (three 200 mi aliquot). The combined organic layers were dried (MgS04) and filtered, and the solvent was distilled off at atmospheric pressure. Crude 3-thiabutane-l-thiol was rectified at reduced pressure (10. 8 g, 100 mmol, 47%), b. p. 120°C/160 Torn l. r. (liquid film) 2580 cm'\ H n. m. r. (270 MHz) 61. 75, t, 1H ; 2. 15, s, 3H ; 2. 73, s, 2H ; 2. 75, s, 2H. 13C n. m. r. 8 15. 28, 24. 13, 38. 14. m/z 108 (100%, M'), 61 (95).

Preparation of 2, 3, 6-Trithiaheptane Me2SO (50 ml) was added to powdered sodium hydroxide (2. 6 g, 65 mmol) and the reaction mixture stirred to produce a homogeneous solution. 3-Thiabutane-l-thiol (3. 0 g, 27 mmol) in Me2SO (20 ml) was added to the reaction mixture which was stirred at room temperature for 5 min. Dimethyl disulphide (6. 5 g, 69. 1 mmol) in MezSO (30 ml) was added and the resultant mixture stirred at ambient temperature for 24 h. Hydrochloric acid (2. 5%, 1 litre) was added and the resultant mixture washed with diethyl ether (three 1 litre aliquot). The combined organic layers were concentrated and the extraction procedure was repeated. The concentrate was covered with 2. 5% sodium hydroxide solution (1 litre) and the resultant mixture extracted with diethyl ether (three 1 litre portions). The combined organic layers were dried (MgS04) and filtered, and the solvent was evaporated. The residue was distilled at reduced pressure giving 2, 3, 6-trithiaheptane as a colourless oil (2. 4 g, 15. 5 mmol, 24%), b. p. 80°C/2 Torr.'H n. m. r. (270 MHz) 5 2. 15, s, 3H ; 2. 43, s, 3H ; 2-83, m, 2H ; 2. 92, m, 2H. 13C n. m. r. 5 15. 54, 23. 45, 33. 54, 37. 24. m/z 154 (1%, M+@), 75 (100).

Preparation of 2, 3, 6-Trithiaheptane 6-Oxide 2, 3, 6-Trithiaheptane (1. 0 g, 6. 4 mmol) was dissolved in 1, 4-dioxan (45 mi) and hydrogen peroxide (0. 37 g, 30%) in 1, 4-dioxan (5 mi) added. The reaction mixture was refluxed behind a safety shield for 30 min. The solvent was evaporated and the residue chromatographed on silica gel (100 g) employing chloroform (100 mi fractions) for elution.

Fractions 9-18 were combined and concentrated affording clean 2, 3, 6-trithiaheptane 6-oxide as a colorless oil (0. 54 g, 3. 1 mmol. 48%). 1. r. (liquid film) 1040 cm-1.'H n. m. r. (270 MHz) 6 2. 42, s, 3H ; 2. 63, s, 3H ; 3. 03, m, 2H ; 3. 09, m, 211. 13C n. m. r. 5 22. 87, 29. 55, 38. 60, 53. 49. m/z 106 (100%), 79 (95).

Preparation of 2, 3, 6-Trithiaheptane 6. 6-Dioxide (10) 2, 3, 6-Trithiaheptane 6-oxide (0. 54 g, 3. 1 mmol) was dissolved in acetone (40 ml) and the reaction mixture cooled to 0°C. Anhydrous magnesium sulfate (3. 8 g) in acetone (10 mi) was added and the reaction mixture stirred at ambient temperature. Potassium permanganate (0. 50 g) was added in three portions at half-hour intervals. Upon

completion of the addition, the reaction mixture was filtered through a Celite pad and the solvent evaporated. The residue was chromatographed on silica gel (50 g) employing 1 : 1 methylene chloride/light petroleum (50 ml fractions) for elution. Fractions 7-11 were combined and concentrated yielding clean (10) (0. 51 g, 2. 7 mmol, 87%).

2, 3, 6-Trithiaheptane 6, 6-dioxide had b. p. 158-162°C/1-4 Torr (Found : C, 25. 9 ; H, 5. 6.

C4H, o0zS3 requires C, 25. 8 ; H, 5. 4%). I. r. (liquid film) 1310, 1145 cm-1.'H n. m. r. (270 MHz) 8 2. 44, s, 3H ; 2. 99, s, 3H ; 3. 08, m, 2H ; 3. 43, m, 2H.'3C n. m. r. b 22. 80, 28. 67, 41. 45, 54. 17. m/z 186 (21%, M+), 106 (80), 79 (100).

Preparation of S-4-Thiapentyl Thioacetate 4, 4-Dioxide (A) 4-Thiapentan-l-ol (Langler, R. F., Marini, Z. A., and Spalding, E. S., Can. J.

Chem., 1979, 57, 3193. (5. 3 g, 49. 5 mmol) and triethylamine (4. 9 g, 48. 5 mmol) in dry pyridine (75 ml) were cooled with an ice/salt/water bath. Methanesulfonyl chloride (5. 8 g, 50. 8 mmoi) was added dropwise over 15 min. The reaction mixture was stirred at ambient temperature for 3 days. Chloroform (100 mi) was added and the resultant mixture washed with 10% hydrochloric acid (50 mi portions) until the aqueous layer remained acidic. The organic layer was dried (MgS04), filtered and concentrated. The residue was rectified at reduced pressure affording impure sulphide methanesulfonate (3. 30 g ; b. p.

110-120°C/2 Torr).

(B) Impure sulphide methanesulfonate (3. 8 g) from step (A) was dissolved in chloroform (75 ml), and the solution added dropwise to 10% sulfuric acid (104 ml).

During the addition, solid potassium permanganate (13. 7 g) was also added in small portions. Upon completion of the additions, the reaction mixture was stirred at ambient temperature for 2 days. The reaction mixture was cooled with an ice/water bath and sodium bisulfite added in small portions until the reaction mixture was decolorized. The layers were separated and the aqueous layer was extracted with chloroform (three 100 ml aliquots). The combined organic layers were concentrated affording impure sulfone methanesulfonate (3. 7 g).

(C) Thioacetic S-acid (1. 3 g) in dry pyridine (30 ml) was added to impure sulfone methanesulfonate (3. 7 g) from step (B) and the reaction mixture stirred at room temperature for 2 days. Chloroform (200 ml) was added and the resultant mixture washed with 2. 5% hydrochloric acid (100 ml aliquots) until the aqueous pH remained acidic. The organic layer was dried (MgS04), filtered and concentrated. Crude sulfone thioacetate was chromatographed on silica gel (250 g) employing 1 : 1 light petroleum/chloroform (100 ml fractions) for elution. Fractions 53-72 were combined and concentrated yielding clean S-4-thiapentyl thioacetate 4, 4-dioxide (0. 93 g, 4. 7 mmol, 8% from 4-thiapentan-1-ol). Recrystallized (methanol) sulfone thioacetate had m. p.

61. 8-62. 7°C (Found : C, 36. 8 ; H, 6. 1. C6H, 203S2 requires C, 36. 7 ; H, 6. 2%). I. r. (KBr) 1690, 1300, 1160, 1130 cm-'.'H n. m. r. (270MHz) S2. 15. quin. 2H ; 2. 36, s, 3H ; 2. 92, s, 3H ; 3. 04, m, 4H. m/z 196 (6%, M+'), 116 (39), 43 (100).

Preparation of 4-Thiapentane-1-thiol 4, 4-Dioxide S-4-Thiapentyl thioacetate 4, 4-dioxide (0. 25 g, 1. 2 mmol) was dissolved in methanol (25 mi) and a solution of sodium hydroxide (0. 08 g, 2. 0 mmol) in water (125 mi) added.

The reaction mixture was stirred at ambient temperature for 1 h. Water (25 ml) and 10% hydrochloric acid (6 ml) were added, and the resultant mixture was extracted with chloroform (four 50 ml aliquots). The combined organic layers ware dried (MgS04), filtered and concentrated giving 4-thiapentane-l-thiol 4, 4-dioxide (0. 13 g, 0. 8 mmol, 67%). The thiol was subjected to a bulb-to-bulb distillation (bath : 200°C ; pressure : 1. 5 Torr). l. r. (liquid film) 2600, 1310, 1145 cm-'.'H n. m. r. (270 MHz) 8 1. 45, t, 1 H ; 2. 17, quin, 2H ; 2. 72, q, 2H ; 2. 95, s, 3H ; 3. 20, t, 2H.'3C n. m. r. 5 23. 21,. 26. 37, 40. 88, 52. 85. m/z 154 (36%, M+'), 74 (100), 41 (76).

Preparation of 2, 3, 7-Trithiaoctane 7, 7-Dioxide (II).

Me2SO (2 ml) was added to powdered sodium hydroxide (0. 10 g, 2. 5 mmol) and the mixture stirred vigorously. 4-Thiapentane-l-thiol 4, 4-dioxide (0. 38 g, 2. 5 mmoi) in Me2SO (4 ml) was added to the reaction mixture which was stirred for 5 min. Dimethyl sulphide (0. 69 g, 7. 3 mmol) in Me2SO (4 mi) was added and the reaction mixture stirred at room temperature for 24 h. Hydrochloric acid (2. 5%, 150 ml) was added and the resultant mixture washed with diethyl ether (three 100 ml aliquots). The combined organic layers were concentrated and the extraction procedure was repeated. Sodium hydroxide solution (2. 5%, 150 ml) was added to the residue and the resultant mixture extracted with diethyl ether (three 100 ml portions). The combined organic layers were dried (MgS04) and filtered, and the solvent was evaporated. The crude product was chromatographed on silica gel (40 g) employing 1 : 1 methylene chloride/light petroleum (40 ml fractions) for elution. Fractions 12-24 were combined and concentrated furnishing clean sulfone sulphide (11) (0. 15 g, 0. 7 mmol, 30%). After recrystallization (methanol), 2, 3, 7-trithiaoctane 7, 7-dioxide (11) had m. p. 34. 8-35. 3°C (Found : C, 30. 1 : H 6. 1. CsH202S3 requires C, 30. 0 ; H 6. 0%). I. r. 1305, 1140 cm-'.'H n. m. r. (270 MHz) S 2. 31, quin, 2H ; 2. 42, s, 3H ; 2. 84, t, 2H ; 2. 94, s, 3H ; 3. 17, t, 2H.'3C n. m. r. 8 21. 50, 23. 00, 35. 55, 40. 85, 52. 87. m/z200 (13%, M'), 121 (100), 79 (76), 41 (78).

Preparation of Methyl 3, 4-Dithiapentanoate (12) Sodium hydride (1. 8 g, 76. 5 mmol) was suspended in Me2SO (30 mi) and methyl thioglycolate (5. 2 g, 49. 2 mmol) in Me2SO (30 ml) was added. After 3 min, dimethyl sulphide (13. 0 g, 138 mmol) in Me2SO (90 mi) was added and the reaction mixture stirred at room temperature for 24 h. Hydrochloric acid (2. 5%, 1 litre) was added to the reaction mixture and the resultant mixture extracted with diethyl ether (three 1 litre aliquot). The combined ether layers were concentrated and the extraction procedure was repeated.

Sodium hydroxide solution (2. 5%, 1 litre) was added to the residue and the resultant mixture extracted with diethyl ether (three 1 litre aliquot). The combined organic layers were dried (MgS04), filtered and concentrated. The residue was rectified at reduced

pressure affording methyl 3, 4-dithiapentanoate (12) (1. 26 g, 8. 2 mmol, 17°ó). The sulphide ester (12) had b. p. 108-110°C/18 Torr (Found : C, 31. 4 ; H, 5. 4. C4H802S2 requires C, 31. 6 ; H, 5. 3%). I. r. (liquid film) 1740 cm'.'H n. m. r. (270 MHz) à 2. 47, s, 3H ; 3. 50, s, 2H ; 3. 77, s, 3H. 13C n. m. r. 5 23. 01, 40. 67, 52. 54, 170. 20. m/z 152 (39%, M+@), 93 (48), 45 (100).

Preparation of 3, 4-Dithiapentan-1-ol Me2SO (30 ml) was added to sodium hydroxide (2. 64 g, 65. 4 mmol). A solution of 2-mercaptoethanol (5. 0 g, 64. 6 mmol) in ME, SO (30 ml) was added and the reaction mixture stirred for 3 min. Dimethyl sulphide (18 g, 281 mmol) in Me2SO (90 ml) was added and the reaction mixture stirred at ambient temperature for 1 week. Hydrochloric acid (2. 5% 1 litre) was added and the resultant mixture washed with diethyl ether (three I litre aliquots). The combined organic layers were concentrated and the extraction procedure was repeated. The residue was dissolved in diethyl ether (1 litre) and extracted with 2. 5% sodium hydroxide solution (1 litre). The organic layer was dried (MgS04) and filtered, and the solvent evaporated. The residue was rectified at reduced pressure furnishing clean 3, 4-dithiapentan-1-ol (2. 1 g, 16. 9 mmol, 26%). The sulphide alcohol had b. p. 155-160°C/80 Torr. l. r. (liquid film) 3250 cm-'.'H n. m. r. (270 MHz) 6 2. 43, s, 3H ; 2. 87, t, 2H ; 3. 08, br s, 1 H ; 3. 88, t. 2H. 13C n. m. r. #6 23. 19, 40. 28, 60. 26. m/z 124 (63%, M), 80 (100), 45 (99).

Preparation of 3, 4-Dithiapentyl Acetate (14) 3, 4-Dithiapentan-l-ol (1. 0 g, 8. 6 mmol) was added to acetyl chloride (20 mi), and the reaction mixture refluxed for 0-5 h. The solvent was evaporated and the residue rectified at reduced pressure affording clean sulphide acetate (14) (0. 44 g, 2. 6 mmol, 30%).

3, 4-Dithiapentylacetate (14) had b. p. 135-140°C/18 Torr (Found : C, 36. 4 ; H, 6. 4.

CsHroo2s2 requires C, 36. 1 ; H, 6. 1%). I. r. (liquid film) 1740 cm'\ H n. m. r. (270 MHz) 8 2. 08, s, 3H ; 2. 43, s, 3H ; 2. 93, t, 2H ; 4. 34, t, 2H. m/z 166 (2%, M'), 87 (51), 43 (100).

The following information and data were published on the website of CSIRO in February, 2000 in the paper mentioned earlier and entitled A New Synthesis for Antifungal a-Sulfone Disulphides.

Compounds (10) and (11) were prepared as shown in. Test results as shown in Table 3 for compounds 8, 9 and 13 appear to establish that the sulfone and sulphide functionalities need be attached to a common carbon for significant fungicidal capacity.

CH, StCH, #X X 2 x 2 ci CH3UCH2hSAc IC34, So (C31,), OsoCH, l j 4 NoOWHp itS^e tnftcxo), Nmi 4 N « H « H, 9StP ß t H, 5<CH, 455CH, CH, S% tCH, hSH ttt Hp, O, CH, SSOt, CHIS tt » O, GI N W1 CH, SO, tCH,), SSOt, flW 1. 3 stet Scheme 1 Reaction of the sulphide propionate (2) with the sodium salt of p-toluenesulfinic acid in either aqueous acetonitrile or aqueous acetone leads to smooth displacement of the propionate group (see Scheme 2).

Scheme 2 Sequential reaction of (4) with thiophenoxide ions and acetyl chloride produces the thioacetate (6) as depicted in Scheme 3.

Scheme 3

An unambiguous synthesis (see Scheme 4) of the sulfone thioacetate corresponding to (6) proved that (6) is not a thioacetate sulfinat ester. sotch CH3-aSCH3 ON-a HSC (O) CH3/ pyridine CH I ---CH3 SCH2SC (0) CH3 2+ CH2SC (O) CH3 (6) (8) Scheme 4 Clearly, sulfinat anion attack on (2) has occurred exclusively with the sulfur atom under our reaction conditions (see Scheme 2).

Schemes 3 and 4 not only establish that (4) is the target a-sulfone sulphide but also establish that (5) is an a-mercapto sulfone.

Typically, preparation of the sulphide ester (2) produces sulphide contaminated with the corresponding sulphide ester (3) (see Scheme 1). Fractional distillation usually leaves a small amount of sulphide ester (3) contaminating distilled sulphide ester (2). It seemed likely that preparation of a sulfone sulphide [e. g. (4), Scheme 2] from (2) would also produce the corresponding sulfone sulphide which would be difficult to remove.

However, neither the sulphide propionate (3) 3 nor the sulphide acetate (9) 3 react with sulfinate anions in warm aqueous acetonitrile (see Scheme 5).

Scheme 5 Thus, a-sulfone disulphides (1 ; R'= CH3), prepared as shown in Scheme 2, are readily purified.

Several other a-sulfone disulphides (1) have been prepared from (2) and tested for fungitoxic activity. Antifungal test results for these a-sulfone disulphides and both sulphide propionate (2) and the a-mercaptosulfone (5) are presented in Table 4.

In connection with a related synthetic problem, the sulphide ester (2) was reacted with potassium p-toluenethiosulfonate. This reaction (see Scheme 6) produced the a- súlfone disuiphide (4). out acetone/H20 CH3SSCH20CCH2CH3 + CH34S02SK o o CH3SSCH2S02 ocH3 50°C a) (4) Scheme 6 Apparently the reagent is transformed, under the reaction conditions, into the potassium salt of p-toluenesulfinic acid.

Preparation of Compounds of Table 4 Previously Prepared Compounds Compound (2) was prepared as described in Georges, N. M., Johnson, M. D., Langler, R. F., and Verma, S. D., Sulfur Lett., 1999, 22, 141.

Preparation of-Sulfone Disulphides (1J (R'= CH3) Table 4 a-sulfone disulphides were prepared in the manner described below for (4).

A solution of sodium p-toluenesulfinate (2. 4 g, 13. 4 mmol) and the sulphide propionate (2) (2. 0 g, 12. 0 mmol) in 1 : 4 water/acetone (30 ml) was immersed in a constant temperature bath at 50°C for 2 h. Chloroform (150 ml) was added and the resultant mixture washed with water (100 ml). The organic layer was dried (MgS04), filtered and the solvent evaporated. The residue was chromatographed on silica gel (200 g) employing 1 : 1 chloroform/light petroleum (100 ml fractions) for elution. Fractions 13-28 were combined and concentrated furnishing the a-sulfone sulphide (4) (1. 6 g, 6. 4 mmol, 53%).

Recrystallized (methanol) a-sulfone sulphide (4) had m. p. 46. 2-48. 6°C (Found : C, 44. 1 ; H, 5. 1. CgH1202S3 requires C, 43. 5 ; H, 4. 9). I. r. 1342, 1148 cm~'.'H n. m. r. (270 MHz) 8 2. 46, s, 3H ; 2. 50, s, 3H ; 4. 20, s, 2H ; 7. 38, d, 2H ; 7. 83, d, 2H.'3C n. m. r. 8 21. 70, 23. 69, 64. 38, 128. 98, 129. 92, 134. 67, 145. 36. m/z248 (6%, M'), 139 (56%), 93 (100%).

Oily PhSO2CH2SSCH3 (obtained in 58% yield) has i. r. 1325, 1155 cm-'.'H n. m. r. (270 MHz) 8 2. 49, s, 3H ; 4. 22, s, 2H ; 7. 60, t, 2H ; 7. 70, t, 1 H ; 7. 96, d, 2H.'3C n. m. r. 6 23. 68, 64. 32, 128. 96, 129. 30, 134. 23, 137. 62. m/z 234 (5%, M+), 125 (28%), 93 (100%).

Oily CH3SO2CH2SSCH339 (obtained in 53% yield) had i. r. 1320, 1145 cm-'.'H n. m. r.

(270 MHz) 5 2. 60, s, 3H ; 3. 05, s, 2H ; 4. 16, s, 2H.'3C n. m. r. 5 23. 61, 39. 33, 61. 38. m/z 172 (10%, M'-), 93 (100%).

Conversion of (4) into the a-Mercatosulfone (5) The a-suifone sulphide (4) (0. 20 g, 0. 81 mmol) was dissolved in a solution of thiophenol (0. 19 g, 1. 7 mmol) in dry methylene chloride (10 ml). Dry pyridine (0. 1 ml) was added and the reaction mixture stirred at ambient temperature for 2 h 10 min. The solvent was evaporated and the residue chromatographed on silica gel (10 g) employing chloroform (5 mi fractions) for elution. Fractions 3 and 4 were combined and dissolved in chloroform (100 ml). The chloroform layer was washed with 2. 5% sodium hydroxide (two 50 ml portions), dried (MgS04), filtered and the solvent evaporated. G. I. c./m. s. established the presence of phenyl methyl disulphide and diphenyl sulphide in these fractions.

Column fraction 5 furnished a mixture (0. 06 g) of unchanged (4) and the a-mercaptosulfone (5). Fractions 6-9 were combined and concentrated yielding clean a-mercaptosulfone (5) (0. 09 g, 0. 44 mmol, 54%). Recrystallized (5) (methanol) had m. p. 86. 4-87. 4°C (Found : C, 47. 3 ; H, 5. 0. C8HoO2S2requires C, 47. 5 ; H, 5. 0). I. r. 2500, 1330, 1170 cm'\ H n. m. r. (270 MHz) 8 2. 21, t, 1 H ; 2. 46, s, 3H ; 3. 94, d, 2H ; 7. 38, d, 2H ; 7. 83, d, 2H. 13C n. m. r. 8 21. 68, 49. 43, 129. 08, 129. 85, 133. 67, 145. 37.

Conversion of (5) into the Sulfone a-Thioacetate (6) The a-mercaptosulfone (5) (0. 06 g, 0. 29 mmol) was covered with acetyl chloride (10 ml) and the reaction mixture refluxed for 1 h. The solvent was evaporated and the residue chromatographed on silica gel (5 g) employing 1 : 4 light petroleum/methylene chloride (5 ml fractions) for elution. Fractions 6-8 were combined and concentrated giving the sulfone thioacetate (6) (0. 024 g, 0. 10 mmol, 34%). (Found : C, 49. 3% ; H, 5. 1 %. C, oH, 203S2 requires C, 49. 2 ; H, 5. 0). I. r. 1720, 1335, 1165 cm-'.'H n. m. r. (270 MHz) 6 2. 30, s, 3H ; 2. 45, s, 3H ; 4. 44, s, 2H ; 7. 34, d, 2H ; 7. 81, d, 2H. 13C n. m. r. 8 21. 70, 29. 94, 52. 09, 128. 93, 129. 71, 134. 20, 145. 39, 190. 41. m/z244 (1%, M+), 150 (31%), 43 (100%).

Conversion of p-Tolyl Methyl Sulphide into the Sulphide Thioacetate (8) (A) A solution of p-tolyl methyl sulphide (5. 0 g, 36. 2 mmol) in dry methylene chloride (50 ml) was refluxed and a solution of sulfuryl chloride (5. 0 g, 37. 3 mmol) in dry methylene chloride (50 ml) added dropwise over 20 min. The solvent was evaporated and the residue rectified at reduced pressure yielding p-tolyl chloromethyl sulphide (7) (2. 6g, 15. 3 mmol, 42%), b. p. 138-142°C/18 Torr.'H n. m. r. (270 MHz) 8 2. 33, s, 3H ; 4. 88, s, 2H ; 7. 15, d, 2H ; 7. 40, d, 2H. 13C n. m. r. 8 21. 11, 51. 83, 129. 48, 129. 97, 131. 67, 138. 34.

(B) Thioacetic S-acid (0. 4 g, 5. 8 mmol) was dissolved in dry pyridine (25 ml) and p-tolyl chloromethyl sulphide (1. 0 g, 5. 8 mmol) added. The reaction mixture was stirred at ambient temperature for 23 h. Chloroform (100 ml) was added and the resultant mixture extracted with 5% HCI (50 ml aliquots) until the aqueous pH remained acidic. The organic layer was extracted with 2. 5% NaOH (50 ml), dried (MgS04), filtered and the solvent evaporated. The residue was rectified at reduced pressure furnishing the sulphide thioacetate (7) (0. 8 g, 3. 7 mmol, 64%), b. p. 138-140°C/1. 7 Torr. I. r. (liquid film) 1700 cm-'.

'H n. m. r. (270 MHz) 6 2. 29, s, 3H ; 2. 33, s, 3H ; 4. 29, s, 2H ; 7. 12, d, 2H ; 7. 32, d, 2H. 13C

n. m. r. 8 21. 11, 30. 39, 34. 75, 129. 82, 130. 62, 131. 46, 137. 69. 194. 34. m/z 212 (55%, M-), 124 (100%), 91 (55%), 43 (65%).

Conversion of (8) into the Sulfone a Thioacetate (6) The sulphide a-thioacetate (8) (1. 0 g, 4. 7 mmol) and hydrogen peroxide (30%, 1. 1 g) were added to 1, 4-dioxan (25 mi) and the reaction mixture refluxed for 0. 5 h. The solvent was evaporated and chloroform (150 ml) added. The chloroform solution was dried (MgS04), filtered and concentrated. The residue was chromatographed on silica gel (100 g) employing chloroform (100 ml fractions) for elution. Fractions 4 and 5 were combined and concentrated affording clean sulfone a-thioacetate (6) (0. 34 g, 1. 4 mmol, 30%). The product was identical to material described under"Conversion of (5) into the Sulfone a- Thioacetate (6)"by i. r.,'H n. m. r. (270 MHz) and'3C n. m. r.

Reaction of the Disulphide Ester (2) with Potassium p-Toluenethiosulfonate The sulphide propionate (2) (2. 0 g, 12. 0 mmol) and potassium p-toluenethiosulfonate (2. 7 g, 11. 9 mmol) were dissolved in 1 : 4 water/acetone (30 ml) and the reaction heated at 50°C for 2 h. Chloroform (200 ml) was added and the resultant mixture extracted with water (100 ml). The organic layer was dried (MgS04), filtered and the solvent evaporated.

The residue was chromatographed on silica gel (200 g) employing 1 : 1 chloroform/light petroleum (100 ml fractions) for elution. Fractions 17-22 were combined and concentrated affording the a-sulfone sulphide (4) (0. 38 g, 1. 5 mmol, 13%) which was identical to (4) described under"Preparation of a-Sulfone Disulphides (1) (R'= CH3)"by i. r.,'H n. m. r. (270 MHz) and 13C n. m. r. spectroscopy.

The next targets selected were (3 ; X = o-SO2CH3) and (3 ; X = p-SO2CH3). Given that benzenesulfonyl chlorides can generally be reduced (LiAIH4) to the corresponding mercaptans (Fong, H. O., Hardstaff, W. R., Kay, D. G., Langler, R. F., Morse, R. G., and Sandoval, D. N., Can. J. Chem., 1979, 57m 1206), we elected to prepare the appropriate methylsulfonyl-substituted benzenesulfonyl chlorides (14) and (15) (Ginige, K. A., Goehl, J. E., and Langler, R. F., Can. J. Chem., 1996, 74, 1638). Lithium aluminum hydride reduction, followed by attempted thiomethylation, as shown in Scheme 7, gave none of the target methyl disulphides, but instead furnished the symmetrical disulphides (7) and (8).

Scheme 7

The disulfone disulphides (7) and (8) are fungitoxic (see Table 5).

The next set of target disulphides included (3 ; X = o-NO2), (3 ; X = m-NO2) and (3 ; X = p-NO2). Each of these molecules contains a most powerful electron withdrawing group and so, were expected to be potent antifungal disulphides. The results for those compounds ( (9), (10) and (11) in Table 1) are in complete accord with expectations.

'Appropriately substituted nitrophenyl or methylsulfonylphenyl aromatics can undergo smooth nucleophilic aromatic substitutions which arylate thiolate anions (Ginige, K. A., Goehl, J. E., and Langler, R. F., Can. J. Chem., 1996, 74, 1638, Baum, J. C., Bolhassan, J., Langler, R. F., Pujol, R. J., and Raheja, R. K., Can. J. Chem., 1990, 68, 1450) in dimethyl sulfoxide or hexamethylphosphoramide (e. g. see Scheme 8).

Scheme 8 Preparation of Compounds of Table 5 The test results (Table 5) for compounds (12) and (13) demonstrate that potential nucleophilic aromatic substitutions which arylate by displacement of the entire sulphide linkage do not inhibit fungal growth.

Previously Prepared Compounds Compound (12) was prepared as described in Ginige, K. A., Goehl, J. E., and Langler, R. F., Can. J. Chem., 1996, 74, 1638 and compound (13) was prepared as outlined in Baum, J. C., Bolhassan, J., Langler, R. F., Pujol, R. J., and Raheja, R. K., Can. J. Chem., 1990, 68, 1450.

Preparation of Phenyl Methyl Disulphide Sodium metal (0. 02 g, 0. 69 mmol) was dissolved in methanol (1 ml) and thiophenol (0. 1 ml) added. The solvent was evaporated and the sodium thiophenate dried in vacuo.

The thiophenate salt was dissolved in dimethyl sulfoxide (10 ml). A portion of the resultant solution (1 ml) was added to a mixture of diphenyl disulphide (1. 98 g, 9. 1 mmol) and dimethyl sulphide (12 ml). The reaction mixture was stirred at ambient temperature for 8 days.

2. 5% Hydrochloric acid (70 mi) was added and the resultant mixture washed with diethyl ether (three-50 mi aliquot). The organic layers were combined, dried (MgS04), filtered and the solvent evaporated. The concentrate was rectified at reduced pressure affording phenyl methyl sulphide (2. 38 g, 15. 2 mmol, 84%), b. p. 82-86°C/1. 8 Torr.'H

n. m. r. (270 MHz) 8 7. 51, d, 2H ; 7. 30, t, 2H ; 7. 20, t, 1 H ; 2. 40, s, 3H. 13C n. m. r. 8 22. 82, 126. 77, 127. 47, 128. 96, 136. 83. m/z 156 (100%, M+), 141 (65%) and 109 (57%).

Preparation of Methyl o-Mercaptobenzoate o-Mercaptobenzoic acid (9. 9 g, 64. 2 mmol) was dissolved in methanol (300 ml) and concentrated sulfuric acid (0. 5 ml) added. The reaction mixture was refluxed for 72 h.

Chloroform (300 ml) was added and the resultant mixture extracted with water (two-100 ml aliquots) and 1 % sodium hydroxide (two-100 ml aliquots). The combined aqueous layers were added to chloroform (75 ml), ice (100 ml) and concentrated hydrochloric acid (8 ml). Chloroform (150 ml) was added, the layers separated, the organic layer dried (MgS04) and filtered. The solvent was evaporated and the residue rectified at reduced pressure affording clean o-mercapto methyl benzoate (6. 9 g, 41. 0 mmol, 64%), b. p. 103-108 C/2. 7 Torr. l. r. (liquid film) 1710 cm-1.'H n. m. r. (270 MHz) 5 7. 99, d, 1H ; 7. 29, d, 1H ; 7. 14, m, 2H ; 4. 68, s, 1H ; 3. 90, s, 3H. 13C n. m. r. 8 167. 09, 138. 27, 132. 45, 131. 65, 130. 86, 125. 74, 124. 62, 52. 19. m/z 168 (21%, M), 136 (100%), 108 (35%).

Preparation of o-Carbomethoxyphenyl Methyl Disulphide (6) Powdered sodium hydroxide (0. 24 g, 6 mmol) was suspended in dimethyl sulfoxide (8 mi) and a solution of o-mercapto methyl benzoate (1. 0 g, 5. 9 mmol) in dimethyl sulfoxide (5 ml) added. The reaction mixture was stirred for 5 min and a solution of dimethyl sulphide (1. 7 g, 18 mmol) in dimethyl sulfoxide (7 ml) added. The reaction mixture was stirred for 24 h at ambient temperature.

2. 5% Hydrochloric acid (150 ml) was added to the reaction and the resultant mixture extracted with diethyl ether (three-100 mi aliquot). The organic layers were combined and concentrated. 2. 5% Hydrochloric acid (150 ml) was added to the concentrate and the resultant mixture washed with diethyl ether (three-100 ml aliquot). The organic layers were combined and concentrated. 2. 5% (W/V) Sodium hydroxide solution (150 mi) was added to the residue and the resultant mixture extracted with diethyl ether (three-100 ml aliquot). The combined organic layers were dried (MgS04), filtered and the solvent evaporated. The crude product was chromatographed on silica gel (100 g) employing 3 : 2 chloroform/light petroleum (100 mi fractions). Fractions 3 and 4 were combined and concentrated and the product rectified at reduced pressure giving clean (6) (0. 09g, 0. 4 mmol, 7%), b. p. 141-142°C/2. 1 Torr (Found : C, 50. 5 ; H, 4. 6. CgH, 002S2 requires C, 50. 4 ; H, 4. 7). I. r. (liquid film) 1705 cm~'.'H n. m. r. (270 MHz) 5 8. 15, d, 1H ; 8. 04, d, 1H ; 7. 58, t, 1H ; 7. 25, t, 1H ; 3. 93, s, 3H ; 2. 40, s, 3H. 13C n. m. r. 5 166. 80, 141. 30, 132. 92, 131. 57, 126. 90, 125. 09, 52. 29, 21. 99. m/z 214 (35%, M'), 167 (100%), 152 (37%), 136 (41 %).

Preparation of o-Chlorophenyl Methyl Sulphide Sodium metal (0. 80 g, 34 mmol) was dissolved in methanol (80 ml) and a solution of o- chlorothiophenol (5. 1 g, 35 mmol) in methanol (10 ml) added. The reaction mixture was cooled with an ice/water bath and a solution of methyl iodide (5. 0 g, 35 mmol) in methanol (10 ml) was added dropwise. The reaction mixture was stirred at ambient temperature for

24 h. Water (100 ml) was added and the resultant mixture extracted with chloroform (three- 100 ml aliquot). The organic layers were combined, dried (MgS04) and the solvent evaporated. The residue was distilled at reduced pressure yielding o-chlorophenyl methyl sulphide (4. 7 g, 29. 7 mmol, 85%), b. p. 80-86°C/3. 0 Torr.'H n. m. r. (270 MHz) 8 7. 33, d, 1H ; 7. 22, t, 1H ; 7. 12, d, 1H ; 7. 07, t, 1H ; 2. 47, s, 3H. 13C n. m. r. 8 137. 70, 131. 75, 129. 69, 129. 34, 127. 18, 125. 46, 15. 13. m/z 160 (33%), 158 (100%, M"), 145 (24%), 143 (66%).

Preparation of o-Chlorophenyl Methyl Sulfone o-Chlorophenyl methyl sulphide (4. 1 g, 25. 9 mmol) in chloroform (86 ml) was added dropwise to 10% sulfuric acid (120 ml). Simultaneously, potassium permanganate (13. 9 g) was added in small portions. The double addition took 45 min. Upon completion of the addition, the reaction mixture was stirred at ambient temperature for 1 h. The reaction mixture was cooled in an ice/water bath and sodium bisulfite added until the reaction mixture became colorless. The layers were separated and the aqueous layer extracted with chloroform (three-100 ml portions). The combined organic layers were dried (MgS04), filtered and the solvent evaporated. Crude chlorosulfone was recrystallized (methanol) affording clean chlorosulfone (4. 0 g, 21. 0 mmol, 81 %), m. p. 93. 5-95. 1°C.

I. r. 1330, 1165 cm-'.'H n. m. r. (270 MHz) 6 8. 15, d, 1 H ; 7. 58, m, 2H ; 7. 48, m, 1 H ; 3. 29, s, 3H. 13C n. m. r. 8 138. 03, 134. 79, 131. 91, 130. 84, 127. 52, 42. 73. m/z 192 (7%), 190 (20%, M+), 113 (33%), 111 (100%).

Preparation of o-Methylsulfonylphenyl Benzyl Sulphide Sodium metal (0. 24 g, 10. 4 mmol) was dissolved in methanol (5 ml) and benzyl thiol (1. 3 ml) added. The solvent was evaporated and sodium benzyl thiolate dried in vacuo. The sodium benzyl thiolate was dissolved in dimethyl sulfoxide (50 ml) and o-chlorophenyl methyl sulfone (2. 0 g, 10. 6 mmol) added. The reaction mixture was stirred at ambient temperature for 19 h. 10% Hydrochloric acid (200 ml) was added and the product filtered off. Dried sulfone sulphide (2. 0 g) was recrystallized (methanol) furnishing o- methylsulfonylphenyl benzyl sulphide (1. 6 g, 5. 8 mmol, 55%), m. p. 132. 0-133. 4°C. l. r.

1315, 1155 cm-'.'H n. m. r. (270 MHz) 8 8. 07, d, 1 H ; 7. 50, m, 2H ; 7. 37, m, 6H ; 4. 24, s, 2H ; 3. 17, s, 3H. 13C n. m. r. 8 139. 47, 137. 15, 136. 08, 133. 59, 131. 05, 130. 10, 128. 93, 128. 70, 127. 67, 126. 42, 42. 05, 39. 28. m/z278 (3%, M--), 91 (100%).

Preparation of o-Chlorosulfonylphenyl Methyl Sulfone (14) o-Methylsulfonylphenyl benzyl sulphide (1. 0 g, 3. 5 mmol) was suspended in glacial acetic acid (35 ml) and water (3ml). C12 (ca 200 ml/min) was bubbled into the reaction mixture for 45 min. Ice/water cooling was employed, as necessary, to maintain the reaction temperature below 30°C. Chloroform (100 ml) was added and the resultant mixture extracted with 2. 5% (W/V) sodium hydroxide (three-50 ml aliquot). The organic layer was dried (MgS04), filtered and the solvent evaporated. The sulfone sulfonyl chloride was recrystallized (dry carbon tetrachloride) yielding

o-chlorosulfonylphenyl methyl sulfone (0. 64 g, 2. 5 mmol, 71%), m. p. 140. 4-142. 2°C. I. r.

1380, 1330, 1155 cm-'.'H n. m. r. (270 MHz) 8 8. 42, t, 2H ; 7. 95, m, 2H ; 3. 41, s, 3H.'3C n. m. r. 6 142. 80, 139. 08, 135. 99, 134. 64, 133. 18, 131. 72, 45. 12.

Preparation of the Disulfone Disulphides (7) and (8) Both sulfone disulphides were prepared as described below for di-o- methylsulfonylphenyl sulphide (7). Note that the preparation of p-chlorosulfonylphenyl methyl sulfone has been described earlier.

(A) Lithium aluminum hydride (1. 2 g, 31. 5 mmol) was added to tetrahydrofuran (20 ml).

A solution of o-chlorosulfonylphenyl methyl sulfone (2. 0 g, 7. 8 mmol) in tetrahydrofuran (80 ml) was added dropwise over 25 min. The reaction mixture was refluxed for 1 h. After cooling to ambient temperature the following chemicals were added sequentially in a dropwise manner : ethyl acetate (20 ml), methanol (10 ml), water (10 ml), 1% hydrochloric acid (40 ml) and concentrated hydrochloric acid (12 ml). Chloroform (250 ml) was added and the resultant mixture washed with water (two-150 ml aliquots). The organic layer was dried (MgS04), filtered and concentrated affording crude phenyl methyl sulfone (0. 33 g).

Phenyl methyl sulfone was recrystallized (methanol) and shown to be identical to authentic material by m. p., mixture m. p., i. r. and'H n. m. r. (60 MHz).

The aqueous layer from the extraction procedure was acidified (12 mi of concentrated hydrochloric acid) and the resultant mixture extracted with chloroform (three-100 ml aliquot). The combined organic layers were dried (MgS04), filtered and the solvent evaporated affording crude oily o-mercaptophenyl methyl sulfone (0. 6 g).

(B) Sodium metal (0. 25 g, 10. 7 mmol) was dissolved in methanol (25 ml) and methanethiol (250 ml) bubbled into the solution. The solvent was evaporated and the sodium methanethiolate dried in vacuo. The sodium methanethiolate was dissolved in dimethyl sulfoxide (15 mi) and a solution of oily o-mercaptophenyl methyl sulfone (1. 9 g, 10 mmol), dimethyl disuiphide (3. 0 g, 31 mmol) and dimethyl sulfoxide (5 mi) added. The reaction mixture was stirred at ambient temperature for 20 h. 2. 5% Hydrochloric acid (150 ml) was added and the resultant mixture extracted with diethyl ether (three-100 mi aliquot). The organic layers were combined, dried (MgS04), filtered and the solvent evaporated. Crude disulfone sulphide (7) was recrystallized from methanol (175 ml).

Clean disulfone sulphide (7) (0. 69 g, 1. 8 mmol, 46% from the sulfonyl chloride) had m. p. 225-227°C (Found : C, 45. 0 ; H, 3. 8. C14H1404S4 requires C, 44. 9 ; H, 3. 8). I. r. (KBr) 1300, 1140 cm-'.'H n. m. r. (DMSO-d6, 270 MHz) 5 8. 06, d, 1 H ; 7. 86, m, 2H ; 7. 65, t, 1 H ; 3. 44, s, 3H. 13C n. m. r. (DMSO-d6) 6 138. 22, 135. 67, 134. 92, 130. 04, 127. 90, 127. 64, 42. 52. m/z 374 (21%, M+), 296 (11%), 234 (15%), 188 (100%).

Clean disulfone sulphide (8) (22% from the sulfonyl chloride) had m. p. 183-185°C (Found : C, 45. 2 ; H, 3. 9. C14H, 404S4 requires C, 44. 9 ; H, 3. 8). I. r. (KBr) 1308, 1155 cm-'.'H n. m. r. (DMSO-d6, 270 MHz) 8 7. 93, d, 4H ; 7. 80, d, 4H ; 3. 22, s, 6H. 13C n. m. r. (DMSO-d6) 6 141. 61, 139. 52, 128. 05, 126. 45, 43. 33. m/z 374 (31%, M+@), 234 (18%), 188 (100%).

Preparation of the Nitrophenyl Disulphides (9), (10) and (11) The nitrophenyl methyl disulphides were prepared from the appropriate symmetrical di (nitrophenyl) disulphides as described below for the para-nitro case.

Sodium metal (0. 018 g, 0. 78 mmol) was dissolved in methanol (10 ml) and methanethiol (20 ml) bubbled into the solution. The solvent was evaporated and the sodium methanethiolate dried in vacuo.

The sodium methanethiolate was dissolved in dimethyl sulfoxide (10 ml). Di (p- nitrophenyl) disuiphide (2. 0 g, 6. 6 mmol) was added to dimethyl sulfoxide (2 ml) and a portion of the methanethiolate solution (1 ml) added. Dimethyl sulphide (12 ml) was added and the reaction mixture stirred at ambient temperature for 8 days. The reaction mixture became homogeneous after stirring for 24 h.

2. 5% Hydrochloric acid (70 ml) was added and the resultant mixture extracted with diethyl ether (three-50 ml aliquot). The organic layers were combined, dried (MgS04), filtered and rotary evaporated. The residue was chromatographed on silica gel (50 g) employing light petroleum (twelve-50 ml fractions) followed by 1 : 1 light petroleum/chloroform (50 ml fractions) for elution. Fractions 13-22 were combined and rectified at reduced pressure affording p-nitrophenyl methyl sulphide (11) (1. 2 g, 5. 9 mmol, 45%), b. p. 146-149°C/0. 9 Torr. (11) crystallized on standing and after recrystallization (methanol) had m. p. 42. 9-44. 3°C.

Clean o-nitrophenyl methyl sulphide (10) (31%) had m. p. 49 - 51°C (Found : C, 41. 9 ; H, 3. 3. C7H7NO2S2 requires C, 41. 8 ; H, 3. 5). I. r. 1524, 1340 cm-'.'H n. m. r. (270 MHz) 6 8. 29, t, 2H ; 7. 71, t, 1H ; 7. 37, t, 1H ; 2. 43, s, 3H. 13C n. m. r. 8 137. 25, 134. 10, 126. 79, 126. 27, 126. 09, 21. 89. m/z201 (14%, M+), 136 (100%), 122 (41%).

Clean m-nitrophenyl methyl sulphide (9) (74%) had b. p. 152-158°C/2 Torr (Found : C, 42. 0 ; H, 3. 6. C7H7NO2S2 requires C, 41. 8 ; H, 3. 5). I. r. 1530, 1350 cm-'.'H n. m. r. (270 MHz) 8 8. 39, s, 1 H ; 8. 04, d, 1H ; 7. 80, d, 1H ; 7. 52, t, 1H ; 2. 49, s, 3H. 13C n. m. r. 5 148. 78, 140. 10, 132. 26, 129. 79, 121. 37, 121. 07, 22. 85. m/z 201 (100%, M'), 140 (48%).

Clean p-nitrophenyl methyl sulphide (11) (45%) had C, 41. 9 ; H, 3. 5. C7H7NO2S2 requires C, 41. 8 ; H, 3. 5. I. r. 1515, 1340 cm-'.'H n. m. r. (270 MHz) 8 8. 20, d, 2H ; 7. 66, d, 2H ; 2. 48, s, 3H. 13C n. m. r. 6 146. 43, 125. 73, 124. 15, 22. 71. mlz 201 (100%, M+-), 140 (56%).

Preparation of Compounds of Table 6 An older example of a-ester sulphide preparation which applied a Pummerer reaction to a thiosulfinate (Saito, I., and Fukui, S., J. Vitaminol. (Kyoto), 1966, 12, 244) is illustrated by the following reaction scheme (see Scheme 9).

Scheme 9 The foregoing reaction appears to proceed through the intermediacy of an acetoxy sulfonium ion. Therefore the direct reaction of a sulphide with dibenzoyl peroxide should produce a benzoyloxy sulfonium ion and, from there, an a-ester disulphide. Relative to prior disclosed reaction schemes, dibenzoyl peroxide provided a significant improvement in the yield of an a-ester sulphide as shown in Scheme 10.

Scheme 10 Although antifungal testing on (4) showed it to be very potent (see Table 6), it was less fungitoxic than several other disulphides, including (3), that have been described earlier (Baerlocher, F. J., Langler, R. F., Frederiksen, M. U., Georges, N. M., and Witherell, R. D., Aust. J. Chem., 1999, 52, 167 ; Langler, R. F., MacQuarrie, S. L., McNamara, R. A., and O'Connor, P. E., Aust. J. Chem. 52, 1119 (1999) ; and Baerlocher, F. J., Baerlocher, M. O., Langler, R. F., MacQuarrie, S. L., and Marchand, M. E., Aust. J. Chem. 53, 1200).

In order to examine a structural variant of (4), the a-ester sulphide PhSSCH20C (O) CH2CH3 (5) was synthesized. Unfortunately, potassium permanganate/propionic acid oxidation of phenyl methyl disulphide only furnishes (5) in 0. 9% yield. Consequently, an alternative two-step synthesis from (3) was developed (vide Scheme 11).

Scheme 11

Compound (2) and (3) are known compounds. Methods of preparing these compounds are also known, these methods having been described in Georges, N. M. Johnson, M. D., Langler, R. F., and Verma, S. D., Sulfur Lett. 22, 141 (1999).

Preparation of Disulphide Benzoate (4) Five parallel reactions were conducted as follows. A solution of dimethyl sulphide (1 : 3 g, 13. 8 mmol) and dibenzoyl peroxide (5. 1 g, 21. 0 mmol) in chloroform (60 ml) was refluxed behind a safety shield for 24 h.

Upon completion of the reflux period, the five runs were combined and chloroform (250 ml) was added. The resultant solution was extracted with 2. 5% sodium hydroxide solution (two-125 ml aliquots). The organic layer was dried (MgS04), filtered and the solvent evaporated. The crude product was rectified at reduced pressure affording a low-boiling fraction (2. 0 g, b. p. 25-80°C/1. 9 Torr). A portion of the low-boiling fraction (1. 0 g) was chromatographed on silica gel employing 1 : 1 chloroform/light petroleum (100 ml fractions) for elution. Methyl methanethiosulfonate (0. 08 g) was obtained.

Based on g. l. c./m. s., the high-boiling distillation fraction (b. p. 80-140°C/1. 6 Torr) contained a mixture of the sulphide benzoate (4) (2. 1 g, 9. 8 mmol) and dibenzoyl anhydride (2. 1 g). In the same manner, the distillation residue was determined to contain the sulphide benzoate (4) (1. 5g, 7. 0 mmol) and dibenzoyl anhydride (9. 1 g). Distillation, at atmospheric pressure, of the condensate from the cold trap, furnished a mixture which contained methyl methanethiosulfonate (0. 7 g).

A sample of the higher-boiling distillation fraction (2 g) was chromatographed on silica gel (200 g) employing 3 : 1 light petroleum/chloroform (100 ml fractions) for elution. Fractions 9-12 were combined and concentrated affording sulphide benzoate (4). The sulphide (4) (0. 6 g) had b. p. 139°C/2 Torr (Found : C, 50. 7 ; H, 4. 6. CgHioOzSz requires C, 50. 4 ; H, 4. 7). I. r. 1720 cm'\ H n. m. r. (270 MHz) 6 2. 51, s, 3H ; 5. 55, s, 2H ; 7. 47, t, 2H ; 7. 60, m, 1H ; 8. 07, d, 2H. 13C n. m. r. 6 24. 48, 73. 55, 128. 52, 129. 51, 129. 77, 133. 4, 165. 76. m/z 184 (9%, M+-CH2O), 105 (100), 77 (36).

Preparation of the Sulfenyl Chloride (6) A solution of sulfuryl chloride (1. 6 g, 11. 9 mmol) in dry methylene chloride (10 ml) was added to a solution of the sulphide propionate (3) 2 (2. 0 g, 12 mmol) in dry methylene chloride (6 ml). The reaction mixture was refluxed for 0. 5 h and the solvent carefully evaporated.

Crude product was distilled at reduced pressure affording impure sulfenyl chloride (6) (0. 8 g). The sulfenyl chloride (6) had b. p. 94-114°C/53 Torr and was not further purified.

Impure sulfenyl chloride (6) had i. r. 1750 cm'.'H n. m. r. (270 MHz) showed major signals at 8 1. 18, t, 3H ; 2. 42, q, 2H ; 5. 60, s, 2H. 13C n. m. r. showed major signals at 8 8. 84, 27. 39, 72. 31, 173. 76. m/z 154 (6%, M+) 118 (11), 57 (100). The sulfenyl chloride (6) was routinely stored in the freezer.

Preparation of the Propionate Disulphide (5) Distilled impure sulfenyl chloride (6) (1. 0 g) was added to a solution of benzene thiol (0. 7 g, 6. 3 mmol) and pyridine (1 ml) in dry methylene chloride (15 ml). The reaction mixture was stirred at ambient temperature for 2 h. Chloroform (100 mi) was added and the resultant mixture washed with 2. 5% HCI (100 ml) and then 2. 5% sodium hydroxide solution (100 ml). The organic layer was dried (MgS04), filtered and the solvent evaporated. The residue was chromatographed on silica gel (100 g) employing light petroleum (twenty-100 ml fractions) followed by chloroform (100 mi fractions). Fraction 22 furnished clean sulphide propionate (5) (0. 53 g. 2. 3 mmol).

The reaction was repeated on impure sulfenyl chloride (6) (2. 0 g) and the chromatographed (5) so-obtained was added to the chromatographed product from the first run. The sulphide was rectified at reduced pressure affording clean (5) (1. 7 g, 7. 4 mmol) whose properties were in full accord with those expected.

Preparation of Compounds of Table 7 Preparation of (CH30C (O) CH2SSCH2C (O) C2H5) methyl 3, 4-dithia-5- propionoxypentanoate Methyl thioglycollate (1. 896 g, 15. 8 mmol) was added to dry methylene chloride (10 ml). CISCH2OC (O) C2H5 (2. 44 g, 15. 6 mmol) was dissolved in dry methylene chloride and the resultant solution added to the reaction mixture. Dry pyridine (2. 5 mi) was added and the reaction mixture stirred at ambient temperature for 24 h.

Chloroform (200 mi) was added to the reaction and the resultant solution washed first with 2. 5% hydrochloric acid (200 ml) then. with 2. 5% sodium hydroxide (200 ml). The organic layer was dried (MgS04), filtered and concentrated.

The residue was chromatographed on silica gel (250 g) employing petroleum ether (200 ml fractions) for fractions 1-19, then chloroform (200 ml fractions). Fraction 23 was concentrated and rectified at reduced pressure affording CH30C (O) CH2SSCHzOC (O) CzH5 (0. 53 g, bp 140-150°C/4. 5 Torr). l. r. 1755 cm-''H n. m. r. (270MHz) 5 1. 17, t, 3H ; 2. 40, g, 2H ; 3. 58, s, 2H ; 3. 77, s, 3H ; 5. 32, s, 2H. 13C n. m. r. 6 8. 84, 27. 55, 41. 76, 52. 63, 72. 65, 169. 54, 173. 63. m/z224 (1%, Mt,), 194 (41%), 57 (100%).

Preparation of ( (C2H50C (O) CH2S) 2) 2, 3-dithiabutane-1, 4-dipropionate (CH3SSCH2OC (O) C2Hs) 2, 3-dithiabutylpropionate (18. 029 g, 109 mmol) was added to propionic acid (350 mi) and the solution refluxed. Portions of potassium permanganate (ca 3 g each, 18. 081 g in total) were added. The solution would immediately turn brown upon the addition of an aliquot of permanganate but would turn white thereafter. Provided the color change took place in less than 5 min, another 3 g portion of permanganate was added. When the color change took longer than 5 min, smaller portions (ca 0. 5 g each) were added at 5 min intervals. Propionic acid (ca 5 ml) was used to rinse each aliquot of permanganate into the reaction mixture. When the last addition had been done (elapsed time 1 h), the reaction mixture was cooled in an ice/water bath.

Chloroform (500 mi) was added and the resultant mixture washed with 10% sodium hydroxide solution (six-250 ml portions), after which the aqueous pH remained basic. The organic layer was dried (MgS04), filtered and concentrated. The residue was rectified at reduced pressure affording unchanged starting material (4. 342 g, bp 161-189°C/I Torr) and (C2HsC (O) OCH2S) 2 (5. 061 g, bp 110-122°C/0. 7 Torr).

* (C2HsC (O) OCH2S) 2 had i. r. 1750 cm'.'H n. m. r. (270 MHz) 5 1. 18, t, 3H ; 2. 42, q, 2H ; 5. 28, s, 2H.'3C n. m. r. 6 27. 5, 72. 7, 173. 5. m/z 208 (14%), 57 (100%).

Preparation of (C2H5C (O) OCH2SSCH2SO2 (C6HJ CH3-p) 1-p-toluenesulfonyl-4- propionoxy-2, 3-dithiabutane ((C2H5C (O) OCH2S) 2) 2, 3-dithiabutane-1, 4-dipropionate (0. 507 g) was dissolved in a solution of acetone/water (4 : 1 respectively, 30 ml). Sodium p-toluenesulfinate polyhydrate (0. 411 g) was added and the reaction mixture heated at 49°C for 2 h. At the end of this period, the reaction mixture was dark orange in color.

Water (100 ml) was added and the resultant mixture washed with chloroform (three 50 mi portions). The combined organic layers were dried (MgS04) and concentrated. Crude product was chromatographed on silica gel (50 g), employing chloroform for elution.

Fractions 10-12 were combined and concentrated affording the product (0. 21 g).

C2H5C (O) OCH2SSCH2SO2 (C6H4) CH3-p had i. r. 1749, 1326, 1151 cm-'.'H n. m. r. 61. 16, t, 3H ; 2. 38, q, 2H ; 2. 47, s, 3H ; 4. 24, s, 2H ; 5. 34, s, ZH ; 7. 38, d, 2H ; 7. 80, d, 2H. 13C n. m. r. 6 8. 82, 21. 70, 27. 41, 63. 93, 72. 38, 128. 99, 129. 94, 134. 43, 145. 49, 173. 43. m/z 290 (13. 7%), 57 (100%).

Preparation of Compound Q, 1-phenyl-1, 2-dithiapropyl propionate, PhSSCH2OC (O) C2H5 (See Table 6) Compound Q is a potent antifungal compound. It's preparation is described in the preprint"New Antifungal Disulphides : Approaching Submicrogram Toxicity", F. J.

Baerlocher"M. O. Baerlocher, C. L. Chaulk, R. F. Langler and E. M. O'Brien, Sulfur Lett.,-in press, the disclosures of which are incorporated herein by reference. See earlier description relative to Scheme 5 for method.

Preparation of N, 2, 3, 5-trithiahexane, CH3SCH2SSCH3 (See Table 3) Sodium metal (0. 020 g) was dissolved in methanol (2 ml) and methanethiol (20 ml) slowly bubbled into the solution. The resultant solution was concentrated and the residue dried in vacuuo. The resulting solid was dissolved in DMSO (10 ml). A portion of this solution (1 ml) was added to a mixture of dimethyl sulphide (12 ml) and (CH3SCH2S) 2 (2. 00 g) (preparation-P. Dubs and R. Stuessi, Helv. Chim. Acta 61, 2351 (1978)). The reaction mixture was stirred at ambient temperature for eight days.

2. 5% Hydrochloric acid (70 ml) was added and the resultant mixture extracted with diethyl ether (three-50 ml aliquots). The organic layers were combined and dried (MgS04), filtered and concentrated. The concentrate was distilled at reduced pressure yielding N

(2. 336 g, bp. 92-102°C/18 Torr). N had'H n. m. r. (270 MHz) 5 2. 22, s, 3H ; 2. 49, s, 3H ; 3. 86, s, 2H. 13C n. m. r. b 65. 12, 73. 39, 94. 23.

Preparation of P, phenacyl methyl disulphide, PhC (O) CH2SSCH3 A) Phenacyl chloride (1. 004 g) was added to dry pyridine (4 ml). Thiolacetic acid (0. 560 g) was dissolved in dry pyridine (6 ml) and added to the reaction mixture. The reaction flask was fitted with a drying tube and the reaction mixture heated at 800°C for 1. 5 h. Chloroform (200 ml) was added and the resultant mixture extracted with 5% hydrochloric acid (150 ml), followed by 2. 5% sodium hydroxide (100 ml). The organic layer was dried (MgS04), filtered and concentrated. The product was chromatographed on silica gel (5 g) employing petroleum ether (400 ml) for elution. Evaporation of the solvent afforded an orange oil.

Fractional distillation provided phenacyl thiolacetate (0. 959 g, bp. 137-139°C/2. 4 Torr).

I. r. 1710, 1685 cm~'.'H n. m. r. (270 MHz) 5 2. 38, s, 3H ; 4. 39, s, 2H ; 7. 46, t, ZH ; 7. 58, t, 1H ; 7. 97, d., 2H. 13C n. m. r. 6 30. 17, 36. 62, 128. 44, 128. 74, 133. 67, 135. 50, 193. 10, 194. 08. m/z 194 (Mt., 3%), 105 (100%).

B) Potassium carbonate (19. 00 g) was added to methanol (147 ml) which was cooled (O°C) and stirred 1 h. Phenacyl thiolacetate (4. 157 g) was added to the reaction vessel dropwise. Cooling and stirring continued for another 30 min. Diethyl ether (205 ml) and water (200 ml) were added and the reaction mixture cooled for another 30 min. Iodine (3. 590 g) was added in small portions over 30 min. Saturated sodium thiosulfate solution (16 mi) was added.

Diethyl ether (85 ml) was added to the reaction mixture and the layers separated. The organic layer was washed with distilled water (two-200 ml aliquot. The organic layer was dried (MgS04), filtered and concentrated in vacuuo. The product was chromatographed on silica gel (400 9) employing chloroform for elution (100 mi fractions). Fractions 16-29 were combined and concentrated. The concentrate was recrystallized from methanol/benzene which produced a crop of gummy crystals (0. 551 g). A second recrystallization furnished phenacyl sulphide with the following properties. I. r. 1675 cm-'.'H n. m. r. 54. 20, s, 4H ; 7. 46, t, 4H ; 7. 59, t, 2H ; 7. 94, d, 4H. 13C n. m. r. 5 45. 36, 128. 74, 128. 77, 133. 68, 135. 35, 194. 30. m/z 105 (100%).

C) Sodium metal (0. 019 g) was dissolved in methanol (10 ml). Methanethiol (20 mi) was bubbled through the solution. The solvent was evaporated and the residue dried in vaccuo. DMSO (10 mi) was added to the solid and the mixture stirred for 30 min.

Phenacyl sulphide (1. 603 g) and dimethyl sulphide were combined and a portion of the DMSO solution (1 ml) was added. The reaction mixture was stirred at ambient temperature for 8 days. 2. 5% Hydrochloric acid (70 ml) was added. The resultant mixture was extracted with diethyl ether (three-50 ml aliquot). The combined organic layers were dried (MgS04), filtered and concentrated.

The crude product was chromatographed on silica gel (200 g) employing 3 : 7 chloroform/petroleum ether (100 ml fractions) for elution. Fractions 12-19 were combined

and concentrated. The residue was rectified at reduced pressure furnishing phenacyl methyl disulphide (1. 121 g, bp. 144-154°'C/1-7 Torr). It had i. r. 1690 cm''H n. m. r. 5 2. 37, s, 3H ; 4. 09, s, 2H ; 7. 47, t, 2H ; 7. 59, t, IH) ; 7. 97, d, 2H. 13C n. m. r. 5 22. 93, 44. 25, 128. 7, 128. 73, 133. 51, 135. 23, 194. 44. m/z 198 (M, 15%), 105 (100%).

Preparation of Compounds in Table 8 Previously Prepared Compounds Compound (2) was prepared as described earlier (angler, R. F., MacQuarrie, S. L., McNamara, R. A., and O'Connor, P. E., Aust J. Chem.-in press). The preparations of compounds (3), (12), (17) and (7) were outlined previously (Baerlocher, F. J., Baerlocher, M. O., Langler, R. F., MacQuarrie, S. L., and Marchand, M. E., Aust. J. Chem.-in press). The synthesis of compound (20) has been reported (Baerlocher, F. J., Langler, R. F., Frederiksen, M. U., Georges, N. M., and Witherell, R. D., Aust. J. Chem., 1999, 52, 167.

Syntheses for compounds (4), (13), (15) and (16) have been described in refs. : Oae, S., Takata, T., and Kim, Y. H., Bull. C. S. Jpn., 1982, 55, 2484 ; Goodridge, R. J., Hambley, T. W., and Haynes, R. K., J. Org. Chem., 1988, 53, 2881 ; Langler, R. F., Ryan, D. A., and Verma, S. D., Sulfur Lett. 24, 51 (2000) ; and Back, T. G., Collins, S., and Krishna, M. V., Can. J. Chem., 1987, 65, 38, respectively.

Three Approaches to the Synthesis of Phenyl Methanethiosulfonate (4J (A) Disulphide Oxidation Methyl phenyl disulphide (See Baerlocher, F. J., Baerlocher, M. O., Langler, R. F., MacQuarrie, S. L., and Marchand, M. E., Aust. J. Chem.-in press.) (1. 0 g, 6. 4 mmol) and hydrogen peroxide (30%, 1. 5 g) were dissolved in glacial acetic acid (25 mi) and the reaction refluxed behind a safety shield for 0. 5 h. Chloroform (100 ml) was added and the resultant mixture extracted with 2. 5% sodium hydroxide solution (three-50 ml aliquot). The organic layer was dried (MgS04), filtered and the solvent evaporated. The crude product was chromatographed on silica gel (100 g) employing 1 : 1 chloroform/light petroleum (100 ml fractions) for elution. Fractions 11 and 12 were combined and concentrated affording clean phenyl methanethiosulfonate (4) (0. 20 g, 1. 1 mmol, 17%). Recrystallized (4) (methanol) had m. p. 88. 9-90. 4EC. I. r. 1335, 1145 cm-'.'H n. m. r. (270 MHz) 5 3. 19, s, 3H ; 7. 54, m, 3H ; 7. 72, d, 2H. 13C n. m. r. 5 47. 39, 127. 93, 129. 92, 131. 67, 136. 24. m/z 188 (35%, M+), 125 (57), 109 (100).

(B) Benzenesulfenyl Chloride From Disulphide, Then Reaction With Methanesulfinate Anions Diphenyl sulphide (1. 0 g, 4. 6 mmol) was dissolved in dry methylene chloride (5 ml) and a solution of sulfuryl chloride (0. 6 g, 4. 6 mmol) in dry methylene chloride (5 mi) added dropwise. Upon completion of the addition, the reaction mixture was refluxed for 0. 5 h.

A solution of sodium methanesulfinate (0. 94 g, 9. 2 mmol) in acetone (40 ml) and water (10 mi) was added to the reaction mixture which was then immersed in a constant temperature bath at 50EC for 1 h. The workup described for part (A) furnished diphenyl sulphide (0. 35 g,

35% from column fractions 2 and 3) and the thiosulfonate (4) (0. 66 g, 3. 5 mmol, 38%, from fractions 7-17).

(C) Benzenesulfenyl Chloride From Mercaptan, Then Reaction With Methanesulfnate Anions Benzenethiol (1. Og, 9. 0 mmol) was reacted with sulfuryl chloride (1. 3 g, 9. 7 mmol) and sodium methanesulfinate (0. 96 g, 9. 4 mmol) as described for diphenyl disulphide in part (B).

Extractive workup and column chromatography, as described in part (B), furnished diphenyl sulphide (0. 11 g, from fraction 3) and the thiosulfonate (4) (0. 95g, 5. 0 mmol, 55%, from fractions 7-11).

Preparation of Methyl Ethanethiosulfonate (5) (A) Sodium benzenethiolate (2. 1 g, 15. 6 mmol) was dissolved in acetone (50 ml) and ethanesulfonyl chloride (1. 0 g, 7. 8 mmol) added. The reaction mixture was refluxed for 1 h.

Chloroform (200 ml) was added and the resultant mixture washed with water (100 ml). The aqueous layer was concentrated and dried in vacuuo for 8 h, producing a mixture (1. 12 g) of sodium ethanesulfinate and sodium chloride. The product had'H n. m. r. (270 MHz, D20 + DSS) 5 1. 08, t, 3H ; 2. 33, q, 2H. 13C n. m. r. 5 7. 90, 56. 44.

(B) Dimethyl disulphide (0. 45 g, 4. 8 mmol) was dissolved in dry methylene chloride (5 ml) and a solution of sulfuryf chloride (0. 65 g, 4. 8 mmol) in dry methylene chloride (5 ml) added dropwise. Upon completion of the addition, the reaction mixture was refluxed for 0. 5 h. A solution of the mixture of sodium ethanesulfinate and sodium chloride (1. 12 g) in water (10 ml) and acetone (40 mi) was added. The reaction mixture was immersed in a constant temperature bath at 50EC for 1 h.

Chloroform (200 ml) was added and the resultant mixture extracted with water (100 ml).

The organic layer was dried (MgS04), filtered and the solvent evaporated. The crude product was chromatographed on silica gel (100 g) employing 1 : 1 chloroform/light petroleum (100 ml fractions) for elution. Fractions 7-9 were concentrated and combined affording oily methyl ethanethiosulfonate (5) (0. 32 g, 2. 3 mmol, 29%). I. r. 1325, 1140 cm-'.'H n. m. r. (270 MHz) 5 1. 48, t, 3H ; 2. 66, s, 3H ; 3. 34, q, 2H. 13C n. m. r. 5 8. 37, 18. 21, 55. 61. m/z 140 (75%, M+), 61 (47), 48 (100).

Preparation of p-Nitrophenyl Methanethiosulfonate (6) p-Nitrophenyl methyl disulphide (See Baerlocher, F. J., Baerlocher, M. O., Langler, R. F., MacQuarrie, S. L., and Marchand, M. E., Aust. J. Chem.-in press.) (1. 0 g, 5. 0 mmol) was dissolved in dry methylene chloride (5 ml) and a solution of sulfuryl chloride (0. 67 g, 5. 0 mmol) in dry methylene chloride (5 mi) added dropwise. The reaction mixture was refluxed for 0. 5 h.

A solution of sodium methanesulfinate (0. 5 g, 5. 0 mmol) in acetone (40 ml) and water (10 ml) was added and the reaction mixture immersed in a constant temperature bath at 50EC for 1 h.

Chloroform (200 ml) was added and the resultant mixture washed with water (100 ml).

The organic layer was dried (MgS04), filtered and concentrated. The crude was recrystallized from methanol (8 ml) and the first crop chromatographed on silica gel (50 g) employing

chloroform (50 ml fractions) for elution. Fraction 4 was concentrated affording clean p- nitrophenyl methanethiosulfonate (6) (0. 31 g, 1. 3 mmol, 26%). The nitrothiosulfonate (6) had m. p. 98-99EC. (Found : C, 36. 1 ; H, 3. 0. C7H7NO4S2 requires C, 36. 0 ; H, 3. 0%). I. r. 1530, 1440, 1145 cm-'.'H n. m. r. (270 MHz) 5 3. 27, s, 3H ; 7. 92, d, 2H ; 8. 33, d, 2H. 13c n. m. r. 5 48. 56, 124. 63, 135. 40, 136. 73, 149. 56. m/z233 (79%, M+), 170 (100).

Preparation of p-Nitrophenylp-Toluenethiosulfonate (8) p-Nitrophenyl methyl disulphide (7) (See Baerlocher, F. J., Baerlocher, M. O., Langler, R. F., MacQuarrie, S. L., and Marchand, M. E., Aust. J. Chem.-in press.) (2. 5 g, 12. 4 mmol) was converted into p-nitrophenyl p-toluenethiosulfonate (8) using the procedure (replace sodium methanesulfinate with sodium p-toluenesulfinate) outlined above for the preparation of (6).

Crude product was not recrystallized but was chromatographed on silica gel (150 g) employing 1 : 1 chloroform/light petroleum (100 ml fractions) for elution. Fractions 3-10 were combined and concentrated and the product recrystallized (methanol). Recrystallized (8) was sublimed (110EC/2 Torr/12 h) affording p-nitrophenyl p-toluenethiosulfonate (8) (1. 4 g, 4. 6 mmol, 37%). The thiosulfonate (8) had m. p. 135-137EC. (Found : C, 49. 6 ; H, 3. 4.

Ci3HnN04S2 requires C, 50. 5 ; H, 3. 6%). I. r. 1525, 1345, 1145 cm-'.'H n. m. r. (270 MHz) 5 2. 44, s, 3H ; 7. 25, d, 2H, 7. 50, d, 2H ; 7. 60, d, 2H ; 8. 18, d, 2H.'3C n. m. r. õ 21. 73, 124. 15, 127. 57, 129. 76, 135. 77, 137. 10, 140. 17, 145. 60, 149. 38.

Preparation of o-Carbomethoxyphenyl Methanethiosulfonate (18) o-Mercapto methylbenzoate (See Baerlocher, F. J., Baerlocher, M. O., Langler, R. F., MacQuarrie, S. L., and Marchand, M. E., Aust. J. Chem.-in press.) (2. 0 g, 11. 9 mmol) was dissolved in dry methylene chloride (5 mi) and a solution of sulfuryl chloride (1. 6 g, 11. 9 mmol) in dry methylene chloride (5 mi) added dropwise. The reaction mixture was refluxed for 0. 5 h.

A solution of sodium methanesulfinate (1. 2 g, 11. 9 mmol) in acetone (40 mi) and water (10 ml) was added to the reaction mixture which was immersed in a constant temperature bath at 50EC for 1 h.

Chloroform (200 mi) was added and the resultant mixture washed with water (100 ml).

The organic layer was dried (MgS04), filtered and the solvent evaporated. Crude product was chromatographed on silica gel (100 g) employing 1 : 1 chloroform/light petroleum (100 ml fractions) for elution. Fractions 8-18 were combined and concentrated affording thiosulfonate (18) (2. 0 g, 8. 1 mmol, 68%). After recrystallization from methanol, o-carbomethoxyphenyl methanethiosuifonate (18) had m. p. 37. 9-38. 4EC. (Found : C, 44. 4 ; H, 4. 1. CgHr004S2 requires C, 43. 9 ; H, 4. 1%). I. r. 1730, 1335, 1140 cm-1.'H n. m. r. (270 MHz) 5 3. 24, s, 3H ; 3. 95, s, 3H ; 7. 61, m, 2H ; 7. 91, m, 2H.'3C n. m. r. 548. 73. 52. 79, 127. 54, 130. 60, 131. 25, 132. 35, 135. 73, 138. 34, 168. 83. m/z 167 (100%, M-CH3S02).

Preparation of Carbomethoxymethyl p-Toluenethiosulfonate (9) A solution of p-nitrophenyl p-toluenethiosulfonate (8) (1. 0 g, 3. 2 mmol) in dimethyl sulfoxide (5 ml) was added to a solution of sodium methylthioglycollate (0. 4 g, 3. 2 mmol) in dimethyl sulfoxide (5 ml) and the reaction mixture stirred at ambient temperature for 2. 5 h.

2. 5% Hydrochloric acid (200 ml) was added and the resultant mixture extracted with diethyl ether (three-100 ml aliquots). The organic layers were combined and concentrated and the extractive procedure repeated. The combined organic layers were dried (MgSO4), filtered and the solvent evaporated. Crude product was chromatographed on silica gel (100 g) employing chloroform (100. mol fractions) for elution. Fractions 6 and 7 were combined and concentrated, yielding oily thiosulfonate (9). I. r. 1745, 1320, 1150 cm-'.'H n. m. r. (270 MHz) 5 2. 47, s, 3H ; 3. 72, s, 3H ; 4. 11, s, 2H ; 7. 38, d, 2H ; 7. 82, d, 2H. 13C n. m. r. 6 21. 73, 53. 08, 60. 93, 128. 54, 129. 90, 135. 71, 145. 52, 162. 99. m/z 228 (3%, Mt CH50), 155 (51), 91 (100).

Administration-Pharmaceutical Compositions For use as a medicine, the compound of the present invention may be administered to an animal including human being either as it is or in the form of a pharmaceutical composition containing, for example, 0. 01-99. 5%, preferably 0. 5-90%, of the compound in a pharmaceutical acceptable nontoxic, inert carrier.

As the carrier, one or more of solid, semisolid, or liquid diluent, filler, and other formulation auxiliaries may be employed. The pharmaceutical composition is preferably administered in unit dosage forms. The pharmaceutical composition of the present invention may be administered orally, parenterally (e. g. intravenously), locally (e. g. transdermally), or rectally. Of course, dosage forms suited for respective routes of administration should be selected.

Oral administration may be carried out using solid or liquid unit dosage forms such as bulk powders, powders, tablets, dragees, capsules, granules, suspensions, solutions, syrups, drops, sublingual tablets, etc.

Bulk powders may be manufactured by comminuting the active substance into a finely divided form. Powders may be manufactured by comminuting the active substance into a finely-divided form and blending it with a similarly comminuted pharmaceutical carrier, e. g. an edible carbohydrate such as starch or mannitol. Where necessary, a corrigent, a preservative, a dispersant, a coloring agent, a perfume, etc. may also be added.

Capsules may be manufactured by filling said finely-divided bulk powders or powders, or granules described below for tablets, in capsule shells such as gelatin capsule shells.

Preceding the filling operation, a lubricant or a fluidizing agent, such as colloidal silica, talc, magnesium stearate, calcium stearate or solid polyethylene glycol, may be blended with the powders. Improvement in the efficacy of the drug after ingestion may be expected when a disintegrator or a solubilizer, such as carboxymethylcellulose, carboxymethylcellulose calcium, low-substitution-degree hydroxypropylcellulose, roscarmellose sodium, carboxymethylstarch sodium, calcium carbonate or sodium carbonate, is added.

Soft capsules may be provided by suspending said finely divided powders in vegetable oil, polyethylene glycol, glycerin, or a surfactant and wrapping the suspension in gelatin sheets. Tablets may be manufactured by adding an excipient to said powders, granulating or slugging the mixture, adding a disintegrator and/or a lubricant, and compressing the

whole composition. A powdery mixture may be prepared by mixing said finely divided powders with said diluent or a base. Where necessary, a binder (e. g. carboxymethylcellulose sodium, methylcellulose, hydroxypropylmethylcellulose, gelatin, polyvinylpyrrolidone, polyvinyl alcohol, etc.), a dissolution retardant (e. g. paraffin), a reabsorption agent (e. g. quaternary salts), and an adsorbent (e. g. bentonite, kaolin, calcium phosphate, etc.) may be added. The powdery mixture may be processed into granules by wetting it with a binder, e. g. a syrup, a starch paste, gum arabic, a solution of cellulose, or a solution of a high polymer, stirring to mix, drying it, and pulverizing the same.

Instead of granulating such powders, it is possible to compress the powders with a tablet machine and crush the resulting slugs of crude form to prepare granules. The resulting granules may be protected against interadhesion by the addition of a lubricant such as stearic acid, a salt of stearic acid, talc or mineral oil. The mixture thus lubricated is then compressed. The resulting uncoated tablets may be coated with a film coating composition or a sugar coating composition.

The compound of the invention may be mixed with a free-flowing inert carrier and the mixture be directly compressed without resort to the above-mentioned granulation or slugging process. A transparent or translucent protective coat consisted of, for example, a hermetic shellac coat, a sugar or polymer coat, or a polishing wax coat may also be applied. Other oral compositions such as a solution, a syrup, and an elixir may also be provided in unit dosage forms each containing a predetermined amount of the drug substance. Syrups may be manufactured by dissolving the compound in suitable flavored aqueous media, while elixirs may be manufactured using nontoxic alcoholic vehicles.

Suspensions may be formulated by dispersing the compound in nontoxic vehicles. Where necessary, solubilizers and emulsifiers (e. g. ethoxylated isostearyl alcohol, polyoxyethylene sorbitol ester, etc.), preservatives, and flavorants (e. g. peppermint oil, saccharin, etc.) may also be added.

Where necessary, the unit dosage formulation for oral administration may be microencapsulated. This formulation may be coated or embedded in a polymer, wax or other matrix to provide a prolonged action or sustained release dosage form.

Parenteral administration may be carried out using liquid unit dosage forms for subcutaneous, intramuscular, or intravenous injection, e. g. solutions and suspensions.

Such unit dosage forms may be manufactured by suspending or dissolving a predetermined amount of the compound of the invention in an injectable nontoxic liquid vehicle, for example an aqueous vehicle or an oily vehicle, and sterilizing the resulting suspension or solution. For isotonizing an injection, a nontoxic salt or salt solution may be added. Moreover, stabilizers, preservatives, emulsifiers, etc. may also be added.

Rectal administration may be carried out by using suppositories manufactured by dissolving or suspending the compound in a low-melting water-soluble or waterinsoluble

solid carrier such as polyethylene glycol, caccao butter, semisynthetic oil (e. g. Witepsol@), a higher ester (e. g. myristyl palmitat) or a mixture thereof.

The invention may be varied in any number of ways as would be apparent to a person skilled in the art and all obvious equivalents and the like are meant to fall within the scope of this description and claims. The description is meant to serve as a guide to interpret the claims and not to limit them unnecessarily.