BACKGROUND OF THE INVENTION

Field of the invention The present invention relates to novel carbamate compounds derived from 2-phenyl-l,3-propanediol monocarbamates. More particularly, the present invention relates to 3-N-substituted thiocarbamoyl-2-phenyl-l,3- propanediol carbamate useful to treat the diseases of the central nervous system. Also the present invention is concerned with methods for preparing the same.

Description of the Prior Art

Carba ates have been effectively used for controlling central nervous system (hereinafter referred to as "CNS") disorders, especially as antiepileptics and centrally acting muscle relaxants. For example, 2-methyl-2-propyl- 1,3-propanediol dicarbamate was reported in J. Am. Chem. Soc, 73, 5779 (1951), and the pharmaceutical activity thereof was ascertained in J. Pharmacol. Exp. Ther., 104, 229 (1952).

U.S. Pat. No. 2,884,444 discloses 2-phenyl-l,3- propanediol dicarbamate and U.S. Pat. No. 2,937,119 discloses isopropyl meprobamate. These carbamate compounds are found to be very effective therapeutic medicines against CNS disorders, in particular, as an antiepileptic and a centrally acting muscle relaxant, respectively.

Active research and development efforts have been and continues to be directed to the application of carbamates for CNS disorders.

SUMMARY OF THE INVENTION

As a result of intensive and thorough research for the derivatives of 2-pheny1-1 , 3-propanediol monocarbamates, the present inventors found that thiocarbamoyl-introduced carbamates are pharmaceutically very useful in prophylaxis and treatment of CNS disorders, for example, epilepsy, cerebral apoplexy and nervous myalgia.

Accordingly, it is a principal object of the present invention to provide novel N-substituted thiocarbamoyl compounds effective for prophylaxis and treatment of CNS disorders.

It is another object of the present invention to provide a method for preparing the novel N-substituted thiocarbamoyl compounds.

DETAILED DESCRIPTION OF THE INVENTION

In accordance with an aspect of the present invention, there are provided novel carbamate derivatives that are pharmacologically superior in prophylaxis and treatment of CNS disorders, represented by the following structural formula I:

wherein R, and R _j may be the same or different from each other and are independently selected from the group

consisting of hydrogen, lower alkyl containing 1 to 8 carbon atoms, and 5 to 7-membered aliphatic cyclic compounds which may comprise two or less nitrogen or oxygen atoms directly unconnected, with a proviso that R ₁ and R, both should not be hydrogen and the total number of carbon atom of _j and R ₂ ranges from 1 to 16.

In accordance with another aspect of the present invention, there are provided novel carbamate derivatives that are pharmacologically superior in prophylaxis and treatment of CNS disorders, represented by the following structural formula I* :

I

S

wherein R ¹ - is alkyloxy carbonyl containing 1 to 8 carbon atoms or aryl containing benzene ring.

In accordance with the present invention, the compound of structural formula I can be prepared as follows:

2-phenyl-l,3-propanediol monocarbamate, represented by the following structural formula II:

is first reacted with sodium hydride and carbon disulfide in a solvent. Without separation, the reaction solution is treated with alkyl iodide represented by the following

structural formula IV:

R ₃ I [IV]

wherein R3 is a lower alkyl containing 1 to 3 carbon atoms, such as methyl, ethyl and propyl, with preference to methyl, to synthesize 3-(alkyldithiocarbonyl)-2-phenγl- 1,3-propanediol carbamate, represented by the following structural formula III:

» s

wherein R is as defined above. Then, this carbamate is reacted with an amine, represented by the following structural formula V:

HNR*R ₂ [V]

wherein R _j and R ₂ may be the same or different from each other and are independently selected from the group consisting of hydrogen, lower alkyl containing 1 to 8 carbon atoms, and 5 to 7-membered aliphatic cyclic compound which may comprise two or less nitrogen or oxygen atoms directly unconnected, with a proviso that R- and R ₂ both should not be hydrogen and the total number of carbon atoms of R- and R ₂ ranges from 1 to 16, to give 3-N- substituted thiocarbamoyl-2-phenyl-l, 3-propanediol carbamate, represented by the following structural formula I:

wherein R. and R are as defined above.

This pathway is summarized in the following reaction scheme:

H R.R _j

In more detail, about 0.1 to 3.0 moles of the compound of structural formula II, the starting material, is added with about 1.0 to 2.0 equivalents of sodium hydride and carbon disulfide each. This reaction system also comprises the alkyl iodide at an amount of about 1.0 to 2.5 equivalents. The synthesis reaction of compound III from compound II is carried out at temperatures of -10 to 30 "C. The examples of solvent used in this reaction include amides such as dimethylformamide, sulfoxides such as dimethyl sulfoxide, and ethers such as ethyl ether and tetrahydrofuran, with preference to ethyl ether and

tetrahydrofuran. When preparing compound I from compound III, the amine is added at an amount of about 1.0 to 5.0 equivalents. This reaction is preferably carried out at temperatures ranging from -10 to 30 ^* C in an ethereal solvent such as tetrahydrofuran.

The following compounds, not limitative but illustrative, are those that can be synthesized by the above-mentioned method.

The following is the method for preparing the compound I' of the present invention.

The compound represented by the structural formula II, is reacted with isothiocyanate represented by the following structural formula VI:

R' _j NCS [VI]

wherein R' _j means an alkyloxy carbonyl containing 1 to 8 carbon atoms or an aryl containing benzene ring, in a solvent, to give 3-N-substituted thiocarbamoyl-2-phenyl- 1,3-propanediol carbamate, represented by the following structural formula I':

wherein R' _j is an alkyloxy carbonyl containing 1 to 8 carbon atoms or an aryl containing benzene ring.

This pathway is summarized in the following reaction scheme:

RjNCS

( M

In the above method, about 0.1 to 3.0 moles of compound II are used along with about 1.0 to 2.0 equivalents of isothiocyanate. This reaction is carried out at temperatures ranging from 30 to 110 ^* C. As a solvent, a halogenated hydrocarbon such as dichloromethane and chloroform, an ethereal solvent such as ethyl ether and tetrahydrofuran, or an aromatic hydrocarbon such as benzene is available with preference to dichloromethane or chloroform.

The following compounds, not limitative but illustrative, are those that can be prepared through the above method.

A better understanding of the present invention may be obtained in light of following examples which are set forth to illustrate, but are not to be construed to limit, the present invention.

EXAMPLE I

Preparation of 3-0-(N-methyl)dithiocarbonyl-2-phenyl-l,3- propanediol carbamate

1000 ml flask equipped with a thermometer was well dried and purged by flowing nitrogen gas into the inside thereof to remove moisture and air which might be present therein, and maintained at 0 ^* C using an ice bath. After

30 min., 10 g of 2-phenyl-l,3-propanediol monocarbamate was dissolved in 250 ml of tetrahydrofuran purified with sodium metal and benzophenone and placed in the flask. A homogeneous solution was made by stirring for 30 min.

While being maintained at 0 °C, the homogeneous

solution was slowly added with 1.4 g of sodium hydride and stirred for 60 min, after which 3.6 ml of carbon disulfide was slowly added using a syringe.

At about 60 min. after the addition of carbon disulfide, thin layer chromatography revealed that all of the starting material disappeared. Reaction was further proceeded by addition of 3.8 ml of methyl iodide while maintaining the reaction solution at 0 ^* C. The progress of the reaction was monitored by thin layer chromatography and liquid chromatography. It took about 2 hours to determine the reaction termination.

Thereafter, the resulting reaction mixture was added with 300 ml of distilled water and 200 ml of ethyl ether, for the purpose of solvent extraction. The organic layer thus obtained was dried over anhydrous magnesium sulfate and the solvent was completely evaporated by a rotary evaporator, to give yellow liquid. This residue was subjected to column chromatography (mobile phase, ethylacetate:n-hexane=l:2) to give 11 g of 3-0-(N- methyl)dithiocarbonyl-2-phenyl-l,3-propanediolcarbamate: Yield 78%.

¹ H-NMR(CDC1 ₃ , 200 MHz), ppm (δ):

2.45-2.50(s,3H) , 3.45-3.60(q,1H) , 4.34-4.39(d,2H) , 4.77-4.83(d,2H), 4.86-5.15(b ,2H) , 7.21-7.39(m,5H)

EXAMPLE II

Preparation of 3-0-(N-methyl)thiocarbamoyl-2-phenyl-l,3- propanediol carbamate

1000 ml flask equipped with a thermometer was well dried and purged by flowing nitrogen gas into the inside thereof to remove moisture and air which might be present

therein, and maintained at 0 "C using an ice bath. After 30 min., 5.7 g of 3-0-(N-methyl)dithiocarbonyl-2-phenyl- 1,3-propanediol carbamate obtained in Example I was dissolved in 200 ml of tetrahydrofuran purified with sodium metal and benzophenone and placed in the flask. A homogeneous solution was made by stirring for 30 min.

While being maintained at 0 "C, the homogeneous solution was slowly added with 4.7 ml of 40 % methylamine solution in water. At about 60 min. after the addition of the aqueous methyl amine solution, the ice bath was removed to proceed the reaction at room temperature. The progress of the reaction was monitored by thin layer chromatography and liquid chromatography. It took about 2 hours to determine the reaction termination.

Thereafter, the resulting reaction mixture was added with 100 ml of distilled water and 100 ml of ethyl ether, for the purpose of solvent extraction. The organic layer thus obtained was dried over anhydrous magnesium sulfate and the solvent was completely evaporated by a rotary evaporator, to give yellow liquid. This concentrated residue was subjected to column chromatography (mobile phase, ethylacetate:n-hexane=l:1) to obtain 5.1 g of 3-0- (N-methyl)thiocarbamoyl-2-phenyl-l,3-propanediol carbamate: Yield 95%.

¹ H-NMR(CDC1 ₃ , 200 MHz), ppm (δ):

2.73-2.78(d,lH), 2.96-3.09(d,2H) , 3.32-3.55(m,1H) , 4.25-4.39(m,2H), 4.62-4.92(br,2H) , 6.41-6.56 (br,lH), 6.92-7.05(br,lH), 7.10-7.38(m,5H)

EXAMPLE III

Preparation of 3-0-(N,N-dimethyl)thiocarbamoyl-2-phenyl-

1,3-propanediol carbamate

The procedure of Example II was repeated using 6.8 ml of dimethyl amine instead of 4.7 ml of 40% aqueous methyl amine solution, to obtain 5.5 g of 3-0-(N,N- dimethyl) thiocarbamoyl-2-pheny1-1 , 3-propanediol carbamate: Yield 97%. m.p. = 114.5-116 ^* C ¹ H-NMR(CDC1 ₃ , 200 MHz), ppm (δ):

2.94-3.04(s,3H), 3.28-3.36(s,3H) , 3.39-3.51(q,1H) , 4.32-4.40(d,2H), 4.63-4.70(d,2H) , 4.71-4.83(br,2H), 7.20-7.36(m,5H)

EXAMPLE IV

Preparation of 3-0-(N-isopropyl)thiocarbamoyl-2-phenyl- 1,3-panediol carbamate

The procedure of Example II was repeated using 5.1 ml of isopropyl amine instead of 4.7 ml of 40% aqueous methyl amine solution, to obtain 5.3 g of 3-0-(N- isopropyl ) thioc rbamoyl-2-pheny1-1, 3-propanediol carbamate: Yield 90%. ^* H-NMR(CDC1 ₃ , 200 MHz), ppm (δ):

1.00-1.13(m,3H) , 1.16-1.27(d,3H) , 3.38-3.57(m,1H) , 3.71-3.90(m,lH), 4.29-4.38(m,2H) , 4.51-4.79(m,4H) , 6.03-6.10(br,lH), 6.38-6.46(br,1H) , 7.18-7.39(m,5H)

EXAMPLE V

Preparation of 3-0-(N-cyclopropyl)thiocarbamoyl-2-phenγl-

1,3-propanediol carbamate

The procedure of Example II was repeated using 4.2 ml of cyclopropyl amine instead of 4.7 ml of 40% aqueous methyl amine solution, to obtain 5.3 g of 3-0-(N-cyclo propyl)thiocarbamoyl-2-phenyl-l,3-propanediol carbamate: Yield 90%.

¹ H-NMR(CDC1 ₃ , 200 MHz), ppm (δ):

0.46-0.88(m,4h), 2.52-2.66(m,1H) , 2.86-2.98(m,3H) , 3.34-3.58(m,lH), 4.28-4.44(d,2H) , 4.57-4.69(d,2H) , 4.70-4.80(br,2H) , 6.37-6.43(br,1H) , 6.76-6.84 (br,lH), 7.16-7.32(m,5H)

EXAMPLE VI

Preparation of 3-0-(N-octγl)thiocarbamoyl-2-phenyl-l,3- propanediol carbamate

The procedure of Example II was repeated using 9.9 ml of octyl amine instead of 4.7 ml of 40% aqueous methyl amine solution, to obtain 7.2 g of 3-0-(N-octyl) thiocarbamoyl-2-phenyl-l,3-propanediol carbamate: Yield

98%.

-H-NMR(CDC1 ₃ , 200 MHz), ppm (δ): 0.81-1.65(m,15H), 3.02-3.17(m,1H) , 3.35-3.56(m,2H) ,

4.28-4.39(m,2H), 4.61-4.75(m,4H) , 6.22-6.37(br,1H) , 6.62-6.76(br,lH), 7.21-7.39(m,5H)

EXAMPLE VII

Preparation of 3-0-(N-piperidyl)thiocarbamoyl-2-phenyl- 1,3-propanediol carbamate

The procedure of Example II was repeated using 6.0 ml of piperidine instead of 4.7 ml of 40% aqueous methyl

amine solution, to obtain 6.1 g of 3-0-(N-piperidyl)thio carbamoyl-2-phenyl-l,3-propanediol carbamate: Yield 95%. - ^• H-NMR(CDC1 ₃ , 200 MHz), ppm (6):

1.34-1.68(m,6H) , 3.39-3.57(m,3H) , 3.88-4.06(br,2H) , 4.28-4.41(d,2H), 4.53-4.64(br,2H) , 4.64- .75(d,2H) ,

7.17-7.34(m,5H)

EXAMPLE VIII

Preparation of 3-0-(N-ethoxycarbonyl)thiocarbamoyl-2- phenyl-l,3-propanediol carbamate

1000 ml flask equipped with a thermometer and a reflux condenser was well dried and purged by flowing nitrogen gas into the inside thereof for 30 min, to remove moisture and air which might be present therein. Then, 19.5 g of 2-phenyl-l,3-propanediol monocarbamate was dissolved in 300 ml of purified dichloromethane and placed in the flask. A homogeneous solution was made by stirring for 30 min.

While being maintained at room temperature, the homogeneous solution was slowly added with 15.7 g of ethoxycarbonyl isothiocyanate using a syringe. Thereafter, temperature was slowly elevated to 40 °C at which the reaction was advanced with stirring. The progress of the reaction was monitored by thin layer chromatography and liquid chromatography. It took about 4 hours to determine the reaction termination.

Thereafter, the resulting reaction mixture was added with 200 ml of distilled water, for the purpose of solvent extraction. The organic layer thus obtained was dried over anhydrous magnesium sulfate and the solvent was completely evaporated by a rotary evaporator, to give

yellow liquid. This residue was subjected to column chromatography (mobile phase, ethylacetate:n-hexane=l:l) to give 26.1 g of 3-0-(N-ethoxγcarbonyl)thiocarbamoyl-2- phenyl-l,3-propanediol carbamate: Yield 80%. -H-NMR(CDC1 ₃ , 200 MHz), ppm (δ):

1.15-1.28(t,3H), 3.38-3.50(m,lH), 4.11-4.20(q,2H) , 4.35-4.44(d,2H), 4.60-4.81(m,2H) , 4.95-5.07(br,2H) , 7.15-7.42(m,5H), 8.80-8.88(br,1H) .

The present invention has been described in an illustrative manner, and it is to be understood the terminology used is intended to be in the nature of description rather than of limitation.

Many modifications and variations of the present invention are possible in light of the above teachings. Therefore, it is to be understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described.