TECHNICAL FIELD

This invention relates . to processes for producing diaryiacetyienes and enamines which are valuable in the synthesis of homopolymers and copoly- mers, for example, poly(arylether)s, polyesters, polycarbonates and polyformals. BACKGROUND ART Advanced composite materials are made from combinations of high performance fibers, such as glass, graphite, carbon, silicon carbide or ceramic fibers, arranged in close packed alignment in the polymer as a matrix. Such composite materials provide a combination of strength and modulus sup¬ erior to that of structural metals and alloys on an equal weight basis. Such composites are, for example, employed in military and commercial air¬ craft, and space vehicles, as well as in sports equipment, in tennis racquets, shafts for golf clubs and sailboats.

These composite materials are expensive, and so their use is confined to relatively high cost items. On the other hand, even though the raw materials for these advanced composites are expen¬ sive, over 70% of the costs associated with such composites result from the processing costs for their manufacture.

In particular, the currently used manu- facturing processes produce volatiles during curing of the polymer matrix and such volatiles produce voids in the matrix which act as sites for structural failure. In order to minimize void formation during evolution of volatiles, the cure must be carried out

over a long period, under reduced pressure and his manufacturing requirement is a major factor in the production cost.

Acetylenic groups have been proposed in polymers in order to provide reactive sites for cross-linking the polymers when heated. The poten¬ tial advantage of such acetylenic groups is that no volatiles will be produced during curing or cross- linking. The acetylenic groups have been introduced into polymer chains as terminal groups, pendant groups or internal groups.

Acetylene precursor polymers have been reviewed by Hergenrother (P. . Hergenrother, J. Marcromol. Sci.-Rev. Macromol. Chem. C19(l), 1-34 (1980).

Most of the polymers with terminal acety¬ lenic groups, that have been synthesized contain unsubstituted ethynyl groups on the ends of the polymer chains and they are generally end-capped low molecular weight oligomers which are synthesized in order to provide easier processability. Reinhardt et al (B. A. Reinhardt, F. E. Arnold and M. R. Unroe, U.S. Patent 4,513,131 (1985)) have synthesized the simple bis(phenylethynylphenyl)ethers as potentially thermally curable resins and studied their thermal curing properties.

Polymers containing pendant phenylethynyl groups have been synthesized and these polymers have been thermally cured. Examples are described in the afore-mentioned Hergenrother article and in U.S.

Patent 4,375,536 (1983) of Hergenrother.

Polymers containing internal acetylene groups have been less studied. T. Takeichi, H. Date and Y. Takayama, J. Pol. Sci. Chem. Ed. 28, 1989

(1990) describes the synthesis of polyimides- contain-

ing internal acetylene groups. The authors indicate that the diphenylacetylene groups must be linked in the metal position to provide effective- cross- linking. Synthesis of Diaryiacetyienes

Synthetic methods are reviewed in "Compre¬ hensive .Organic Chemistry" Pergamonn Press, 1979, Vol. 1 and in The Chemistry of the Carbon-Carbon Triple Bond, Ed. Saul Patai, John Wiley & Sons 1978, Part 2.

I. Dehydrohalogenation Reactions

The most common method of synthesis is by dehydrohalogenation reactions of iodo, bromo or chloro compounds with strong bases, usually KOH, NaOH, alkoxides such as sodium methoxide or potassium tertiary butoxide or sodamide, or with hydrides, e.g. sodium hydride or with organometallic compounds such as butyl lithium.

-CHX-CHX- base -CH2"CΛ2" —C≡C—

-CH-CX- ^C=CHX— X- I, Br, Cl

The elimination of other groups, thiols, sulfides, sulfonic acids, phosphate esters, trialkyl tin hydrides and the elimination of tertiary amines in a Hofmann elimination has also been observed (pp. 776-81 of the afore-mentioned S. Patai).

II. Displacement Reactions

Copper acetylides can react with aryl halides to give diaryiacetyienes (p 796 of S. Patai) and aryl halides also react with acetylenes in the presence of palladium catalysts (p 798 of S. Patai):

Ar—X Ar ^* —C≡C-Cu Ar'—C≡C-Ar

Pdcat.

Ar—X Ar'—C≡C—H Ar'—C=C-Ar

Benzotriazole, benzimidazole and triazoles have been shown by Katritzky to behave as pseudo- halogens in certain reactions, (e.g. A. R- Katritzky, Q.-H. Long and P. Lue _r Tetrahedron Letters, 32,3597 (1991) they have demonstrated that dienamines can be synthesized from substituted benzotriazoles by reaction with sodium hydride.

In this reaction the benzotriazole moiety behaves as a pseudohalogen and is eliminated with base in the same way a halogen like bromine would be.

This is discussed further in a review article (A.R. Katritzky, S. Rachwal and G. J. Hutchings, Tetra¬ hedron 47,2683 (1991) .

The production of enamineε is described in U.S. Patent 5,011,998 (1991) of A. S. Hay et al. As described by Hay et al, the enamines are readily hydrolyzed to deoxybenzoins which in turn are readily oxidized to benzils which are useful in the pro¬ duction of a variety of polymers. Published European Patent Applicaton

0,076,628, Rohm and Haas Company describes certain enamines having fungicidal activity. DISCLOSURE OF THE INVENTION

This invention provides a novel synthesis for chemical intermediates for polymer production.

This invention also provides processes for the production of diaryiacetyienes.

Further, this invention provides a process for the production of enamines. Still further this invention provides novel enamines.

This invention also provides a novel process for producing polymers having acetylenic linkages. Still further this invention provides novel polymers incorporating acetylenic linkages.

In accordance with one aspect of the invention there is provided a process for producing a chemical intermediate for polymer manufacture co - prising: reacting a Schiff's base of formula (III):

Ar _; ,CH=NAr ₂ (III)

with an N-arylmethylheterocycle of formula (IV):

Ar ₃ -CH ₂ -N ^ (IV ⁾

in a basic medium wherein Ar,, Ar_ and Ar- are each independently selected from aryl and hetaryl, unsub- stituted or substituted, one or more times, by radicals selected from F, Cl, - Br; alk l of 1 to 6 carbon atoms; alkenyl of 2 to 6 carbon atoms; aryl of 6 to 12 carbon atoms; aralkyl of 7 to 18 carbon atoms; aralkenyl of 8 to 18 carbon atoms, alkoxy of 1 to 6 carbon atoms; thioalkoxy of 1 to 6 carbon atoms; aryloxy of 6 to 12 carbon atoms; and thioaryloxy of 6 to 12 carbon atoms; and -N J is a hetaryl radical.

If the process is operated under conditions favouring the elimination of the heterocyclic of formula (V) :

H-N ) (V)

the reaction proceeds to form a diarylacetylene of formula ( ) :

in which Ar, and Ar, are as defined above, as the favoured reaction.

If the process is operated under conditions which do not favour elimination of the heterocyclic of formula (V) :

H-N ) (V)

the reaction forms an enamine of formula (II):

Ar.-CH=C-Ar. (II)

N

wherein Ar. , Ar, and -N j are all as defined above.

In another aspect of the invention there is provided enamines of formula (II), as defined above, in which the hetaryl radical -N is other than imidazolyl.

In yet another aspect of the invention there is provided a process for producing diaryl- acetylenes from the enamines (II).

In still another aspect of the invention there is provided a process of producing polymers and copolymers incorporating acetylenic compounds.

In yet another aspect of the invention there is provided novel polymers and copolymers having acetylenic groups incorporated therein. DESCRIPTION OF PREFERRED EMBODIMENTS i) Synthesis' of Intermediates

A novel synthesis of the invention com- prises the reaction of the Schiff's base of formula

(III), as defined above with the N-arylmethylhetero- cycle of formula (IV), as defined above in a basic medium.

This reaction can produce a diarylacetylene of formula (I), as defined above, or an enamine of formula (II), as defined above, or a mixture contain¬ ing both.

The hetaryl radical -N ) is, in particular, one which behaves as a pseudohalogen, and if the reaction conditions favour elimination of the hetero- cycle of formula (V) :

H - (V)

the reaction proceeds with formation of the diaryl- acetylene (I) as the major reaction product, whereas if the reaction conditions do not favour elimination of heterocycle (V) , the reaction proceeds with formation of the enamine (II) as the major reaction produc .

In general, higher reaction temperatures in conjunction with strongly basic conditions favour the elimination reaction which results in the diaryl- acetylene (I) as the major reaction product. In contrast, lower reaction temperatures in conjunction with weakly basic conditions do not favour the elimination reaction, thus leading .to the enamine (II) as the major reaction product.

Reaction time is also a factor in determin¬ ing whether the diarylacetylene (I) or the enamine (II) is the dominant reaction product.

Depending on the inter-relationship between these different process parameters, the reaction product may be predominantly the diarylacetylene (I) or the enamine (II), or a mixture of both in varying proportions.

The reaction resulting in the diarylacety- lene (I) proceeds via the enamine (II) as an inter¬ mediate. The diarylacetylene (I) can be produced from the intermediate enamine (II) in situ, or the enamine (II) can be recovered or isolated from the reaction medium and subjected to conditions favouring formation of the diarylacetylene (I).

Thus the invention contemplates reaction of the Schiff's base (III) and the N-arylmethylhetero- cycle (IV) under basic conditions favouring elimi¬ nation of the heterocycle (V) so that the reaction proceeds to the diarylacetylene (I) via the enamine

(II). The invention also contemplates reaction of (III) and (IV) under first basic conditions which do not favour elimination of the heterocycle (V) to produce the enamine (II), and thereafter,- possibly with prior isolation of the enamine (II), reacting the enamine (II) under second basic conditions effective for elimination of the heterocycle (V) to produce the diarylacetylene (I).

The invention also contemplates the elimi- nation process in which the diarylacetylene (I) is produced from the enamine (II), as starting material, ii) Process Parameters for Synthesis

The synthesis i) is carried out under basic conditions, more especially in a basic medium. In particular, the medium, suitably com¬ prises a polar, aprotic organic solvent, for example, dimethylformamide, dimethylacetamide or N-methylpyr- rolidone, which medium is rendered basic. The base character,may be achieved by the presence of a base, for example, sodium or potassium tert-butoxide, sodium amide or sodium dimethyl amide; the sodium dimethyl amide may be generated in situ from sodium in N,N-dimethyl formamide. Mixtures of the bases may be employed. As indicated above the base selected plays a role in determining whether the formation of the diarylacetylene (I) or the enamine (II) is favoured.

Since some heterocycles (V) have a strongly acidic character, the heterocycle (V) formed as a by-product of the formation of the diarylacetylene (I) from the enamine (II), may act as a buffer in the reaction medium, weakening the basic character and favouring termination of the reaction with formation of enamine (II) .

The synthesis can be carried out con¬ veniently at temperatures in the range of 0 to 100 ^o C; while still lower or higher temperatures, outside this range can be employed; there is no advantage in . employing temperatures outside this range.

In general lower temperatures in the range favour the first stage of the reaction to produce enamine (II) as the major reaction product. On the other hand, higher temperatures alone do not dictate continuation of the reaction through the enamine (II) to the di rylacetylene (I) ; and at the higher temperatures, the reaction time and the strength of the basic character of the reaction medium play a significanat role in determining which reaction product, (I) or (II), dominates; and, as indicated above, when considering the basic character of the reaction medium, it is not only the strength of the base employed which is to be considered, because the acidity of by-product heterocycle (V) also affects the basic character.

On the other hand, a surprisingly fast reaction to form a high yield of diarylacetylene (I) has been observed employing a basic reaction medium of potassium t-butoxide in dimethylformamide even when benzotriazole, which is strongly acidic, was formed as the by-product heterocycle (V) . • At a temperature of 75 C. the reaction proceeded to form the diarylacetylene in high yield in a reaction time of less than 1 minute.

At lower temperatures, however, the benzo¬ triazole released buffered the reaction to favour the enamine (II) as the reaction product.

The rapid reaction with benzotriazole as the heterocyclic (V) presumably results from the high electron withdrawing character of the benzotriazolyl radical . iii) Reactants

The Schiff's bases (III) are readily produced in condensation reactions between aromatic aldehydes and aromatic amines, a reaction fully described in prior literature. The N-arylmethylheterocycles (IV) are readily produced by the reaction between arylmethyl- halides and aromatic heterocyclic compounds under conditions for elimination of hydrogen halide, a reaction fully described in prior literature. The aryl radicals Ar. , Ar_ and Ar_ are suitably aromatic radicals having 6 to 16 carbon atoms in the aromatic nucleus, independently selected from:

wherein x and y are integers independently selected from 0, 1, 2 or 3, z is an integer independently selected from 0, 1 or 2 and R, R ¹ and R" are each independently selected from halogen atoms selected from fluorine, chlorine and bromine; alkyl of 1 to 6 carbon atoms, alkenyl of 2 to 6 carbon atoms; aryl of 6 to 12 carbon atoms, aralkyl of 7 to 18 carbon atoms; aralkenyl of 8 to 18 carbon atoms; alkoxy of 1 to 6 carbon atoms; thioalkoxy of 1 to 6 carbon atoms; aryloxy of 6 to 12 carbon atoms and thioaryloxy of 6 to 12 carbon atoms.

The hetaryl radicals Ar,, Ar_ and Ar, may be, for example, pyridinyl, furanyl, thiophenyl, thiazolyl or quinolinyl, which may be unsubstituted or substituted in the manner of the aryl radicals described above; for example the radicals:

The heterocyclic radical

- may be,_ for example, a benzimidazolyl, benzotri- azolyl, triazolyl or tetrazolyl, which radicals may be unsubstituted or substituted. It will be under¬ stood that the nature of the substituent is immate¬ rial, provided that it does not interfere with the reaction to produce the desired enamine (II) or diarylacetylene (I).

iv) Polymer Production

Diaryiacetyienes of formula (VI):

X ₁ -Ar ₄ -CSC-Ar _f .-X ₂ (VI)

in which X, and X ₂ are independently selected from F and OH, and Ar ₄ and Ar.. are aryl or hetaryl as defined for Ar, and Ar,, are starting materials for producing polymers which incorporate acetylenic groups.

The diaryiacetyienes (VI) in which X, and X~ are both fluorine are within formula (I) and are produced by the previously described synthesis of the inventio .

The diaryiacetyienes (VI) in which at least one of X, and ₂ is a hydroxyl are produced from the corresponding diaryiacetyienes (VI) in which X, and X ₂ are fluorine, by hydrolysis of one or both fluorine substituents or etherification of one or both fluorine substituents and hydrolysis of the resulting alkoxy or aryloxy substituents. The reaction to replace one or both fluorine substituents by an alkoxy or aryloxy is a novel reaction and it was surprising that such reaction would proceed efficiently. It appears that the acetylenic linkage activates the fluorine atom, facilitating its displacement, but this was not to have been expected. The reaction proceeds efficiently in the presence of an alkali metal alkoxide or aryloxide in a polar, aprotic organic solvent. The reaction is illustrated in the follow- ing scheme

F-Ar ₄ -C=C-Ar ₅ -X + 2-0R F-Ar ₄ -C=C-Ar ₅ ~OR

RO-Ar . -C=C- Ar ₅ -OR

in which X is H or F and R is alkyl or aryl, and Ar. and Ar- are as defined previously.

The production of homopolymers and copoly¬ mers, particularly poly(arylether)s, polyesters, polycarbonates and polyformals from diaryiacetyienes (VI) is illustrated below:

POLY(ARYL ETHER)S

POLYESTERS

POLYCARBONATES and POLYFORMALS

Y» CH _2l C-O

In these reactions n is an integer indicating the length of the polymer chain.

Any bisphenol can be employed as the reactant HO-Ar-OH in the production of the poly(aryl- ether). The radical Ar. is an aromatic moiety such as diphenylsulfone or benzophenone . When X is fluorine Ar, can also be a heterocyclic which acti¬ vates the fluorine for nucleophilic substitution, for example, pyridine, benzoxazole, quinoxaline, an isoquinoline or a phthalazine.

Thus in another aspect of the invention there is provided a process for producing an acety¬ lenic group-containing polymer or copolymer of the formula (VII):

Z ₁ - Ar ₄ -C=C-Ar ₅ -Y ₁ -Z ₃ - ₂ -) _Hr —<X*~ Z ₂ (VII)

wherein Z, is fluorine, hydroxyl or mercaptyl, Z ₂ is hydrogen or fluorine, Z, is -0-, -S-, -CH ₂ ~, -CO-, -CO-Ar _g -CO- or -Ar--, in which Ar _g and Ar_ are selected from divalent aromatic linkages, Y, and ₂ are each selected from -O- and -S-, provided that when Z, is -O- or -S-, Y, and Y ₂ are both single bonds, Ar. and Ar_ are each independently selected from arylene and hetarylene, unsubstituted or substituted one or more times by radicals selected from F, Cl, Br, alkyl of 1 to 6 carbon atoms; alkenyl of 2 to 6 carbon atoms; aryl of 6 to 12 carbon atoms; aralkyl of 7 to 18 carbon atoms; aralkenyl of 8 to 18 carbon atoms, alkoxy of 1 to 6 carbon atoms, thioalkoxy of 1 to 6 carbon atoms, aryloxy of 6 to 12 carbon atoms and thioaryloxy of 6 to 12 carbon atoms; X is -Ar ₄ -C≡C-Ar ₅ or a copolymer unit, ^• n is an integer of 2 to 200, x is an integer of 0 to 199 and n is x.

It will be understood that the two basic units of (VII) may be in a random or non-random arrangement or sequence in the case of a copolymer.

In still another aspect of the invention there is provided an acetylenic group-containing polymer or copolymer of formula (VII) as defined above provided that when the polymer or copolymer has acetylenic units -Ar ₄ ~C=C-Ar ₅ - at both terminal positions, n is at least 3. The divalent linkages -Ar.,- are in particular derived from dihydroxy aromatics, for example, bisphenols, or from dihaloaromatics in which the halo groups are activated by the presence of electron withdrawing groups such as sulphonyl or carbonyl groups.

Aromatic groups having electron withdrawing groups are thus, for example:

-Ar-CO-Ar- and

-Ar-S0 ₂ -Ar-

in which the Ar groups are the same or different and are arylene or hetarylene.

The divalent aromatic linkages Ar _fi are selected from a broader class than Ar ₇ since no electron withdrawing group is required in Ar ₇ . ^ The copolymer unit X may be derived from a wide variety of comonomers, for example, the following comonomer units in which the free valencies are in ortho or para positions.

in which Ar, , ^Ar _? ' ^Ar ₇ ^{and Ar} ₄ ^are independently selected from unsubstituted and substituted aryl.

in which Ar,, Ar ₂ , Ar ₃ and R ₄ are as defined above and Ar is aryl.

in which R ₂ is alkylene or arylene

The aromatic moieties of the dihydroxy aromatics may be, for example, arylene and biarylene moieties including the following:

The diaryiacetyienes (I) as a class can be readily oxidized to corresponding benzils useful in synthesis of • a variety of polymers including poly- quinoxalines, polyphenyls and phthalic anhydrides and the latter can be reacted with diamines to produce polyimides.

The enamines (II) of the invention are useful for the production of deoxybenzoins which can be oxidized to benzils which have utility in the production of polymers. The processes, involving use of enamines, described in U.S. Patent 5,011,998, the teachings of which are hereby incorporated herein by reference, apply to the enamines (II) of the present invention. Thus deoxybenzoins, benzils and polymers may be produced using the enamines (II) of this invention, and the procedures described in U.S. Patent 5,011,998, incorporated herein by reference.

EXPERIMENTAL

K ₂ C0 ₃ Ar CH ₂ C1 + Ar ₂ H — - ^ Ar CH ₂ Ar ₂

CH ₃ CN Ar = Aryl group

.1. Synthesis of N-Beπzyl-subslituted Heterocyclics

Example 1.

(Phenylmetlιyl)-IH- benzimidazole. To benzyl chloride (13 g, 0.103 rnol), 1H- benzimidazole (11.81 g, 0.10 mol), K ₂ C0 ₃ (60 g, 0.434 raol) was added acetoni- trile (200 mL) and the mixiure was stirred and heated under reflux for 3 h, filtered hot,.and washed with hot CH ₃ CN (100 mL). The solvent of the filtrate was evapo¬ rated and the residual mass recrystallized as needles (16.5 g, 79%): mp 119- 120°C (benzene) Gi ¹ mp 105°C); ^l H NMR (270 MHz, CDC1 ₃ ) δ 5.40 (s, 2H, CH ₂ ).7.20-7.41 (m, 8H), 7.85-7.89 (m, IH), 8.02 (s, IH, NCHN); IR (CDCI3) 3093 (w), 3065 (w), 3037 (w), 2929 (w), 1615 (w), 1496 (s), 1456, 1385 (w), 1361, 133 1285, 1261, 1204, 1181, 1007 (w), 963 (w), 947 (w) cm" ¹ . MS (El) m/e 208 (M ⁺ , 57.8), 91 (100); Anal. Calcd for C ₁₄ H ₂₂ N ₂ (208.26): C, 80.74; H, 5.81; N, 13.45; Found: C, 80.70; H, 6.02; N, 13.31. ^l Feigl, F.; Gleich, H. Monatsh. 1928, 49, 385-400. Example 2. (Phenylmethyl)-1H- benzotriazole. (Phenylmelhyl)-lH-benzoiriazole was pre¬ pared from lH-benzotriazole (11.91 g, 0.100 mol) and benzyl chloride as in Ex¬ ample 1 for 1 hour to give the title compound and (phenylmethyl)-2H- benzotria¬ zole in a ratio of 75:25. orkup and two recrystallizations gives the pure 1H- isomer: mp 117-119 °C (CH ₃ CN); (lit. ¹ mp 114-117 °C; lit. ² - ³ mp 115-116 °C) tøaramunt, R. M.; Elguero, J.; Garceran, R. Hetewcycles 1985, 23, 2895. ² Marky, M; Schmid, H; Hansen, H. J. Helv. Chin Acta 1979, 62, 2129. ³ Rondeau, R. E.; Rosenberg, H. M.; Dunbar, D. J. /. Mol Spectry. 1969, 29, 305. Example 3.

(Pl.enylmethyl)-IH- [1,2,4-triazole]. (Pheny.me-hyl)-lH-[l,2.4-triazolc] was prepared from lH-[ 1,2,4-triazole] (69.7 g, 0.100 mol) and benzyl chloride as in Example 1 for 1 hour to give the title compound and (phenylmcthyl)-2//-[ 1,2,4- triazole]. Workup and recrystallization gave the pure lH-isomer (54%): mp 52- 53°C (cyclohexane); (lit. ¹ mp 54 °C).

^laramunt, R. M.; Elguero, J.; Garceran, R. Heterocycles 1985, 23, 2895. Example 4.

(2-Naphthalenyl)methyl-lH-benzotriazole. A procedure similar to Example 2 from lH-benzotriazole and 2-naphthylmethyl chloride gave the title compound af- ter recrystallization in 45% yield: mp 152-153 °C (CΗ ₃ CN); ^l H NMR (200 MHz, CDC1 ₃ ) δ 6.03 (s, 2H, CH ₂ ), 7.32-7.38 (m, 4H), 7.48-7.53 (m, 2H), 7.77-7.83 (m, 4H), 8.07-8.12 (m, IH). Example 5. (l-Naphthalenyl)methyMH-benzotriazole. A procedure similar to Example 2 from lH-benzotriazole and 1-naphlhylmemyl chloride gave the tide compound af¬ ter recrystallization in 85% yield: mp 149-151 °C (ElOAc/petroleum ether 35-60 "C abbreviated elsewhere as PE); *H NMR (200 MHz, CDCI3) δ 6.36 (s, 2H, CH ₂ ), 7.29-7.59 (m, 7H), 7.87-7.93 (m, 2H), 8.06-8.11 (m, IH), 8.21-8.26 (m, IH). Example 6.

(4-FIuorophenyl)methyl-lH-benzotriazole. In a procedure as in Example 2 but using lH-benzotriazole (23.8 g, 0.200 mol), l-(chloromethyl)-4-fluorobenzene (29.0 g,0.200 mol) and K ₂ C0 ₃ (70 g) in CH ₃ CN (300 mL) for 1 hour gave the ti¬ de compound and (4-fluorophenyl)mediyl-2H-benzotriazole. Workup and recrys- tallizadon gave the mixture of the IH and 2H-isomers (75 % yield) which was used in the subsequent reactions. A sample (5 g) was chromatographed (PE/ ElOAc 9:1) eluting first the 2H isomer and then the title compound: mp 92-94 °C (cyclohexane); ^l E NMR (300 MHz, CDC1 ₃ ) δ 5.82 (s, 2H, CH ₂ ), 7.00-7.06 (m, 2H), 7.25-7.46 (m, 5H), 8.08 (d, J=8.9 Hz, IH); IR (CDC1 ₃ ) 3052 (w), 2938 (w), 1609, 1513, 1451 (w), 1351 (w), 1315 (w), 1269 (w), 1230 (s), 1159, 1084 cm ^"1 . MS (El) m/e 227 (M ⁺ , 52.6), 198 (100), 109 (96.9); Anal. Calcd for C ₁₃ H ₁₀ N ₃ F (227.24): C, 68.71; H, 4.44; F, 8.36; N, 18.49; Found: C, 68.44; H, 4.44; F, 8.40; N, 18.57. Example 7. (3-Fluorophenyl)methyl-lH-benzotriazole. In a procedure as in Example 2 but using IH-benzotriazole (20.6 g, 0.173 mol), l-(chloromeU yl)-3-fluorobenzene

(25.0 g, 0.173 mol), K ₂ C0 ₃ (35.9 g) and CH ₃ CN (150 mL) for lh gave d e ude compound and (3-fluorophenyl)medιyl-2H-benzolriazole. Similar workup and re¬ crystallization gave the pure lH-isomcr (73%): mp 103-104°C (cyclohexane); ^X H NMR (270 MHz, CDC1 ₃ ) δ 5.87 (s, 2H, CH ₂ ), 6.97-7.08 (m, 3H), 7.29-7.49 (m, 4H), 8.10 (d, J=8.0 Hz, IH); Anal. Calcd for C ₁₃ H ₁₀ N ₃ F (227.24): C, 68.71; H, 4.44; Found: C, 68.40; H, 4.67. Example 8.

(2-Fluorophenyl)methyl-lH-benzotriazole. In a procedure as in Example 2 but using lH benzotriazole (34.5 g, 0.289 mol) and l-(chloromedιyl)-2- fluorobenzene (41.8 g, 0.289 mol) for lh gave the tide compound and (2- fluorophenyl)methyI-2H-benzotriazole in a rado of 80:20. Similar workup and re¬ crystallization gave die pure lH-isomer (73%): mp 93-95°C (cyclohexane); *H NMR (270 MHz, CDC1 ₃ ) δ 5.93 (s, 2H, CH ₂ ), 7.08-7.47 (m, 7H), 8.10 (d, J=7.2 Hz, IH). II. Synthesis of Scliiff Bases

Ar ₃ CHO + Ar ₄ NH ₂ Ar ₃ CH=NAr ₄ + H _z O

Ar ₃ , Ar ₄ = Aryl group

Example 9.

N-[(4-fluorophenyI)methylene]benzenamine. To 4-fluorobenzaldehyde (24.8 g, 0.200 mol) and aniline (18.6 g, 0.200 mol) was added benzene (200 mL) and ace¬ tic acid (0.7 mL) and the mixture is heated under reflux until all die water (3.6 mL) was azeotropically removed. The solvent is evaporated and die residual oil upon cooling and sύrring crystallized. The white mass was then recrystallized as needles (28 g, 70%) : mp 39-40 °C (PE) (lit. ¹ mp 40 °C). toayaL S. K.; Ehrenson, S.; Taft, R. W. J. Am. Chem. Soc. 1972, 94, 9113. Example 10.

N-[(3-fluorophenyI)memylene]benzenamine. ^1,2 A similar procedure as for die preparation of N-[(4-fluorophenyl)medιylene]benzenamine (no acetic acid re¬ quired) gave an oil which was distilled (87%): bp 100-101°C/0.75 mm Hg. ¹ Liepins, E.; Pesiunovich, V. A.; Eremeev, A. V.; Tikliomirov, D. A.; Gaidarova, N. P. Kim. Getewtsikl. Soedin. 1977, 906-909; Chen Abstr. 1977, 87, 183795b. ² Fauran, C; Bergeron, H.; Raynaud, G.; Thomas, J.; Eberle, J. Fr. Demande 2, 262, 51326 Sep 1975; Chem. Abstr. 1976, 84, 121843v.

Example 11.

N-[(2-fluorophenyl)methylene]benzenamine. A similar procedure as for the preparation of N-[(4-fluorophenyl)medιylene]benzenamine (no acetic acid re¬ quired) gave an oil which was distilled (90%): bp 103-104°C/1.5 mm Hg pres- sure; (lit. ¹ bp 135°C).

^essar, S. V.; Gopal, R.; Singh, M. Tetrahedron 1973, 29, 167.

III. Synthesis of Enamines

Ar CH ₂ Ar ₂ + Ar ₃ CH=NAr ₄ »~

(l,2-diphenylethenyl)-lH-benzotriazole. Example 12. Method 1.

To a mixture of powdered OH (2.24 g, 0.040 mol) and DMF (18 L) there was added witii rapid stirring phenylmethyl-lH-benzotriazole (1.05 g, 0.005 mol) and N-phenylmediylenebenzenamine (0.905 g, 0.005 mol) in DMF (7 mL) al 75 °C. After five minutes the reaction was poured into ice-cold water (75 mL) and left to crystallize the title enamine. This was filtered, washed with water, and dried to yield 1.07 g (72%) of die tide enamine. An analytical sample was chromato¬ graphed PE/ElOAc 4:1 and recrystallized with charcoal treatment: mp 152-154 °C (cyclohexane); Anal. Calcd for C ₂₀ H ₁₅ N ₃ (297.36): C, 80.78; H, 5.08; N, 14.13; Found: C, 80.66; H, 5.14; N, 14.14. Example 13. Method 2.

A procedure similar to Example 12 except that instead of KOH potassium t- butoxide ( 0.56 g, 0.005 mol) was used. At 75 °C d e reaction was complete and worked up as above. Chromatography first with PE elutes some (5-10%) diphenyl acetylene and then PF/ElOAc 4:1 elutes the title enamine (75-80%). This method was applied to other bases as given in Table 1. Example 14.

(l,2-DiphenylethenyI)-lH-benzimidazole. A procedure as in Example 13 using (phenylmethyl)-lH- benzimidazole gave die enamine (82%): mp 141-143 °C (cy¬ clohexane); ^J H NMR (300 MHz, CDC1 ₃ ) δ 6.82 (m, 2H), 6.98 (d, J=8.0 Hz, IH), 7.14-7.19 (m, 5H), 7.25-7.38 (m, 6H), 7.83 (s, IH, NCHN), 7 (88, J=d, 9.0 Hz,

1H); IR(CDC1 ₃ ) 3085 (w), 3063, 3032 (w), 1635, 1611 (w), 1491 (s), 1484, 1452, 1391, 1365 (w), 1308, 1284, 1259, 1218, 1183 (w), 1078 (w), 1031 (w), 1006 (w) cm" ¹ . MS (ED m/e 296 (M ⁺ , 100), 219 (13), 178 (52); Anal. Calcd for C ₂₁ H ₁₆ N ₂ (296.38): C, 85.11; H, 5.44; N, 9.45; Found: C, 85.03; H, 5.50; N, 9.45. Example 15.

[l,2-bis(4-fluorophenyl)ethenyI)]-lH-benzotriazole. A procedure as in Exam¬ ple.13 using (4-Fluorophenyl)metiιyl-lH-benzotriαzole. gave die title enamine (60 %): mp 134-136 °C (cyclohexane); MS (El) in/e 333 (M+, 5), 305 (50), 304 (100), 303 (32), 215 (20), 214 (23), 183 (62); Anal. Calcd for C ₂₀ H ₁₃ F ₂ N ₃ (333.34): C, 72.06; H, 3.93; F, 11.4; N, 12.61; Found: C, 72.28; H, 3.93; F, 11.11; N, 12.74. IV. Synthesis of Acetylenes

ArCHaAra + Ar ₃ CH«NAr ₄ - Ar ₃ ~ Ar ■« Ar, Ar ₃ , Ar ₄ « Aryl groups

Diphenylacetylene. General Procedure.

Example 16. Method a. To potassium t-butoxide (3.36 g, 30 mmol) in DMF (40 mL) at 75 °C was added as quickly as possible and all at once the [arylmediyl]- lH-benzotriazole (10 mmol) and N-(arylmethylene)benzenamine (10 mmol) dis¬ solved in DMF (10 mL). Witiύn a minute d e solution is poured into ice-cold wa- ter (150 mL), extracted with CHC1 ₃ (3 x 50 mL) and chromatographed (PE). The acetylenes were recrystallized from MeOH. Thus was obtained: diphenylacetylene (75 %): mp 59-61 °C (MeOH); IR (CDC1 ₃ ) 1650 (w), 1604 (w), 1589 (w), 1512 (s), 1233, 1155 (w) cm' ¹ . Example 17. Mediod b. To potassium t-butoxide (5.6 g, 50 mmol) in DMF (40 mL) at 75 °C was added N-(phenylmethyl)-lH-benzimidazole (2.08 g,10 mmol) and N-(phenylmedιylene)benzenamine (1.81 g,10 mmol) dissolved in DMF (10 mL). After 5 hours the solution is poured into ice-cold water (150 mL), extracted witii CHCI3 (3 x 50 mL) and chromatographed (PE). Diphenylacetylene was ob¬ tained in 73 % yield. Example 18. Mediod c.To potassium t-buloxide (5.6 g, 50 mmol) in DMF (40 mL) at 75 °C was added N-(phenylmedιyl)-lH-l,2,4-triazole (1.59 g,10 mmol) and N-(phenylmedιylene)benzenamine (1.81 g,10 mmol) dissolved in DMF (10 mL). After 30 minutes the solution is poured into ice-cold water (150 mL), ex¬ tracted with CHCI3 (3 x 50 mL) and chromatographed (PE). Diphenylacetylene

was obtained in 11 % yield.

Table 1: Influence of different bases and temperatures on the reaction of phenyl- methy-lH-benzotriazole (5 mmol) and N-phenylmethylenebenzenamine (5 mmol) in DMF (25 mL) in the production of the enamine (1) and diphenylacetylene (2).

Example 28. l-(Phenylethynyl)naphthalene. In a procedure similar to that of Example 16 us¬ ing [phenylmedιyl]-lH-bcnzotriazole (10 mmol) and N-([l- naphdιalenyl]medιylene)benzenamine (10 mmol): 88% yield: mp 51-53°C (MeOH) (Ut ¹ oil); 1H NMR (300 MHz, CDC1 ₃ ) S 7.39-7.69 (m, 8H), 7.77-7.90 (m, 3H), 8.46 (br d, 2.7H, IH); IR (CDC1 ₃ ) 3060 (s), 2245 (eyne), 1596, 1581, 1508, 1491 (s), 1442, 1398, 1333, 1215, 1070, 1017 cm" ¹ . MS (El) m/e 228 (M ⁺ , 100). ¹ Dessy, R. E.; Kandil, S. A. J. Org. Chem 1965, 30, 3857. Example 29. l-Methoxy-4-(phenylethynyl)benzene. Procedure similar to that of Example 16 using [phenylmelhyl]-lH-benzotriazole (10 mmol) and N-[(4- medιoxyphenyl)methylene]benzenamine (10 mmol): 67% yield: mp 57-58 °C (MeOH) (lit. ¹ 58-60 °C); ^l E NMR (300 MHz, CDC1 ₃ ) δ 3.84 (s, 3H, OCH ₃ ), 6.89

(d, 1.9H, 2H, C(3 and 5)H), 7.30-7.38 (m, 3H), 7.45-7.54 (m, 4H).

¹ Katritzky, A. R.; Boulton, A. J.; Short, D. J. J. Chem. Soc. 1960, 1519.

Example 30.

Bis(4-fluoroplιenyl)acetylene. To potassium t-butoxide (1.5 g, 13.4 mmol) in DMF (15 mL) at 75 °C was added as quickly as possible and all at once [(4- fluorophenyl)methyl]-lH-benzoiriazole (1.14 g, 5 mmol) and (4- fluorophenyI)med ylenebenzenamine (1.00 g, 5 mmol) dissolved in DMF (10 mL). Witiύn a minute die solution is poured into ice-cold water (75 mL) crystal¬ lizing die tide compound which was filtered and d en chromatographed (PE). The acetylene 0.54 g (50%) recrystallizes as needles : mp 95-96 °C (MeOH); (lit. ¹ 94- 95 °C).

¹ Gascoyne, J. M.; Mitchell, P. J.; Phillips, L. J. Chem. Soc, Perkin Trans. 2 1977, 1051. Example 31. 4-(t-Butoxy)-4 ^, -fiuorodiphenylacetylene. A similar procedure s for die prepar¬ ation of bis(4-fluorophenyl)acetylene in Example 30 but stirred at75°C for 15 min and tiien quenched with water gave die title acetylene (15% HPLC) and bis(4- fluorophenyl)acetylene (30% HPLC). Chromatography (PE) elutes d e difluoro derivative then PE/EtOAc 97:3 elutes the tide compound recrystallizing as color- less plates 2.5 g (10%): mp 102-104°C (MeOH); ^l R NMR (200 MHz, CDC1 ₃ ) δ 1.35 (s, 9H, (CH ₃ ) ₃ ), 6.93-7.06 (dd, J=8.6 Hz, 4H), 7.39-7.51 (m, 4H); IR (CDC1 ₃ ) 3020 (w), 2981, 2247 (w,(acetylenic stretch), 1605, 1515 (s), 1474 (w), 1393 (w), 1367, 1281 (w), 1234, 1218, 1157 (s) cm' ¹ . MS (El) m/e 268 (M+ (4.5)), 212 (100), 183 (28), 157 (9.4); Anal. Calcd for C ₁₈ H ₁₇ FO (268.33): C, 80.57; H, 6.39; Found: C, 80.10; H, 6.42. Example 32.

4,4'Bis(t-Butoxy)diphenylacetyIene. A similar procedure as for die preparation of bis(4-fIuorophenyl)acetylene.]in Example 30 but using 5 equiv of potassium t- butoxide for 150 minutes and tiien quenched with water gave the title acetylene (45% HPLC). Chromatography (PE/EtOAc 9:1) and recrystallization with char¬ coal treatment gave 0.64 g (40%) colorless prisms: mp 129-131°C (MeOH); ^X H NMR (300 MHz, CDC1 ₃ ) δ 1.36 (s, 18H, C(CH ₃ ) ₃ ), 6.96 (d, J=8.7 Hz, 4H, phenyl C3 and 3'H), 7.43 (d, 4H, phenyl C2 and 2Η); IR (CDC1 ₃ ) 3040 (w), 2980, 2936 (w), 2907, 2875, 1606, 1511, 1475 (w), 1394, 1367, 1309 (w), 1240, 1158 (s), HOI (w), 1016 (w) cm ^"1 . MS (El) m/e 322 (M ⁺ , 6.1), 266 (4.1), 210 (100). Example 33.

l,2-Bis(4-hydroxyphenyl)-ethanone. To a solution of acetic acid (15 L), c. HC1 (2.0 mL) and H ₂ 0 (3.0 mL) was added l,l'-(l,2-ethynediyl)bis[4-(l,l- dimethylethoxy) benzene] (1.0 g, 3.1 mmol) and heated under reflux 1.5 h. Then d e solution was poured into ice-cold H ₂ 0 (50 mL) precipitating the tide com- pound which was filtered washed with water, air-dried, and recrystallized into tanned needles (.52 g, 80% yield). A second recrystallization with charcoal treat¬ ment and acidification of the solution gave colorless needles: mp 217-220°C (H ₂ 0) (lit ¹ mp 214-215°C); NMR (300 MHz, DMSO-d ₆ ) δ 4.09 (s, 2H, CH ₂ ). 6.66 (d, J=8.45 Hz, 2H, C9H), 6.82 (d, J=8.7 Hz, 2H, C2H), 7.02 (d, 2H, C8H), 7.89 (d, 2H, C3H), 9.23 (s, IH, CIOOH), 10.34 (s, IH, CIOH); ¹³ C NMR (300

MHz, DMSO-d ₆ ) δ 43.44 (£H ₂ ), 115.11, 115.20, 125.58, 127.85, 130.36, 130.54, 131.02, 131.17, 155.85, 161.97, 196.18 (C=0); MS (El) m/e 228 (M ⁺ , 4), 121 (100), 107 (14.8), 93 (13), 65 (15). ^incke, Th.; Fries, K. Justus LiebigsAnn. Chem. 1902, 325, 67. Example 34. l-Hydroxy-4-(phenylethynyi)benzene. A procedure similar to that described ¹ was used. A sample of l-methoxy-4-(phenylethynyl)-benzene (0.4 g, 1.9 mmol) was added collidine (3 mL), Lil (1.5 g) and die solution heated under reflux for 5h (>95% conversion). The solution was poured into water acidified with HC1, ex- traded with ether (3 x 50 mL) and dried (MgS0 ₄ ). The edier was evaporated and the residue chromatographed (PE) eluting the tide compound 0.3 (80%): mp 125-128°C (cyclohexane) (lit ² mp 91-92°C, lit ³ mp 83-84°C); ^X H NMR (300 MHz, DMSO-d ₆ ) δ 6.80 (d, J=8.77 Hz, 2H, C2H), 7.37 (d, 2H, C3H), 7.35-7.42 (m, 3H), 7.46-7.50 (m, 2H), 9.92 (s, IH, OH); ¹³ C NMR (300 MHz, DMSO-d ₆ ) δ 87.32 (acetylenic C), 89.98 (acetylenic C), 112.42 (sp ² C), 115.74, 122.90 (sp ² C), 128.20, 128.66, 131.06, 133.00, 158.06 (COH); IR (CDC1 ₃ ) 3596 (OH), 3066 (w), 3039 (w), 2217 (w, acetylenic stretch), 1605, 1512, 1429 (w), 1328 (w), 1261 (s), 1219, 1171 (s), 1140 (w), 1099 (w), 834, 805 (w) cm" ¹ . MS (El) m/e 194 (M ⁺ , 100), 165 (29.4), 97 (11.3). Harrison, I. T. J. Chem. Soc, Chem. Commun. 1969, 616.

² Veschambre, H.; Dauphin, G.; Kergomard, A. Bull. Soc Chim. Fr. 1967, 2846.

³ Huysmans, W. G. W. Dissertation Leiden 1964.

Example 35.

4,4'-Bis(phenoxy)diphenylacetyIene. To 4,4'-difluorotolane (0.5 g, 0.0023 mol) and dry potassium phenolate (prepared from aqueous KOH and phenol witii azeo- tropic removal of H ₂ 0 with benzene) (1.5 g, 0.011 mol) was. added DMF (10 mL)

and the mixture heated at 170°C for 12 h after which there appeared a liulc difluo- rotolαne remaining. This mixture was poured in water, the precipitate was filtered, washed wid water.dried, and the tide compound recrystallized as flakes 0.54 g (64%); mp 171-173°C (acetic acid) (lit. ¹ mp 167-168°C); ^X H NMR (270 MHz, CDCI ₃ ) δ 6.89 (d, J=8.7 Hz, 4H, phenylene C3.3Η), 6.97 (d, J=8.6 Hz, 4H, phenyl

C2, 2Η), 7.07 (t, J=7.9 Hz, 2H, phenyl C4H), 7.29 (t, 4H, phenyl C3.3Η), 7.40 (d, 4H, phenylene C2.2Η); IR (CDC1 ₃ ) 3041 (w), 3020 (w), 1590, 1512, 1488, 1312 (w), 1274 (w), 1238 (s), 1218, 1165 (w), 1020 (w) cm' ¹ . When the sample is placed in a DSC apparatus witii a N ₂ gas flow ramped at 10°C min it shows a Tm=163.9°C. In a gas-tight crucible and the temperature ramped at 2°C/min diis sample shows Tm=169.5°C and an exolherm maximum at 359.3°C.The exotherm begins at -302°C and ends at -396°C. Some of tiiis material is heated in a closed glass capillary tube at 320-330°C for 6 h and tiien an aliquot of die product was chromatographed (HPLC). The retention times (tR in min) and area % were: 4.43 (8), 4.63 (6), 9.02 (40), 13.08 (6.5), 19.24 (15).

^ u, K. S.; Arnold, F. E. Org. Prep. Proced. Int. 1980, 12, 327. Example 36.

3,3'-Difluorodiphenylacetylene. A similar procedure to Example 30 but using [ (3-fluorophenyl)metf.yl]-lH-benzouiazole and (3- fluorophenyl)med ylenebenzenamine, gave die tide acetylene after recrystalliza¬ tion (30%) needles: mp 60-62°C (MeOH) (lit. ¹ mp 61-62°C, lit mp 55.5-58°C); ^X HNMR (300 MHz, CDCI ₃ ) δ 7.04-7.11 (m, 2H), 7.22-7.25 (m, 2H), 7.31-7.35 (m, 4H); ¹³ C NMR (300 MHz, CDC1 ₃ ) δ 88.89 (2.9, ethynyl C), 115.92 (21.1, C4), 118.42 (22.9, C2), 124.60 (9.5, Cl), 127.54 (2.9, C6), 129.97 (8.7, C5), 162.36 (246.7, C3).

^arpino, L. A.; Chen, H.-W. J. Am. Chem. Soc 1979, 101, 390. ² Bender, D. F.; Thippesway, T.; Rellahan, W. L. J. Org. Chem. 1970, 35, 939. Example 37.

2,2'-DifluorodiphenylacetyIene. A similar procedure to Example 30 but using [ (2-fluoropheπyl)meu yl]-lH-benzotriazole and (2- fluorophenyl)methylenebenzenamine, gave die title acetylene after chromatogra¬ phy (PE) and recrystallization (15%) needles: mp 53-54°C (MeOH); ^X H NMR (200 MHz, CDCI3) δ 7.05-7.16 (m, 4H), 7.27-7.38 (m, 2H), 7.50-7.58 (m, 2H); ¹³ C NMR (200 MHz, CDCI3) δ 88.05 (2.6, acetylenic C), 112.03 (15.8, Cl), 116.02 (21, C3), 124.49 (3.8, C6), 130.83 (8, C4), 134.06 (C5), 163.24 (253, C2); IR(CDC1 ₃ ) 3040 (w), 2228 (w, acetylenic stretch), 1951 (w), 1917 (w), 1883 (w),

1799 (w), 1700 (w), 1615 (w), 1576, 1501, 1447 (s), 1413 (w), 1321 (w), 1264 (s), 1224 (s), 1155 (w), 1100, 1030 cm" ¹ . MS (El) m/e 214 (M ⁺ , 100), 107 (12.8). Example 38. 2,4'-Difluorodiphenylacetylene. A similar procedure to Example 30 but using [ (4-fluorophenyl)methyl]-lH-benzotιiazole (1.14 g, 5 mmol) and (2- fluorophenyl)methylenebenzenamine (1.00 g, 5 mmol), gave d e title acetylene af¬ ter recrystallization (50%) needles: mp 108-109°C (MeOH); ^l ¥L NMR (200 MHz, CDC1 ₃ ) δ 7.0-7.18 (m, 4H), 7.24-7.38 (m, IH), 7.45-7.59 (m, 3H); ¹³ C NMR (200 MHz, CDC1 ₃ ) δ 82.77 (acetylenic Cl), 93.72 (3.35, acetylenic Cl'), 112.21 (15.39, Cl), 116.03 (21.07, C3), 116.16 (22.18, C3'), 119.50 (3.41, Cl'), 124.50 (3.67, C6), 130.57 (8.04, C4), 133.99 (8.15, C5 or C2'), 134.16 (8.5, C5 or C2'), 163.24 (252.45, C2 or C4'), 163.32 (250.7, C2 or C4'); IR (CDC1 ₃ ) 2263 (w), 2247 (ety- nyl stretch, w), 1600 (C=C), 1574 (w), 1510 (s), 1489, 1451, 1264, 1228, 1156, 1096, 1029 (w) cm" ¹ . MS (El) m/e 214 (M ⁺ , 100). Example 39.

3,4'diπuorodipheιιylαcetylene. A similar procedure to Example 30 but using [ (4-fluorophenyl)methyl]-lH-benzotriazole (1.14 g, 5 mmol) and (3- fluorophenyl)methylenebenzenamine (1.00 g, 5 mmol), gave die title acetylene af¬ ter recrystallization (60%) needles: mp 88-89 °C (MeOH). Example 40.

Bis(2-naphthyl)acetylene. A procedure similar to Example 16 using N-([2- naphdιalenyl]methylene)benzenamine and 2-naphthylmethyl chloride gave a 76% yield of product : mp 225-226°C (MeOH) (lit. ¹ mp 228-229 °C). ^akasuji, K.; Akiyama, S.; Akashi, K.; Nakagawa, M. Bull. Chem. Soc Jpn. 1970, 43, 3567. Example 41.

Bis(l-naphthyl)acetylene. A procedure similar to Example 16 using N-([l- naphdιalenyl]meihylene)benzenamine and 1-naphthylmethyl chloride gavea 67% yield of product: mp 127-128°C (MeOH) (lit. ¹ mp 129 °C). ^l Nakasuji, K.; Akiyama, S.; Akashi, K.; Nakagawa, M. Bull. Chem. Soc Jpn. 1970, 43, 3567. Example 42.

Methylenebis(4-oxyphenylethynyl)bisbenzene. A procedure similar to Example 16 but using [phenylmethyl]-lH-benzotriazole (2.09 g,10 mmol) and 4,4'- medιylenedioxybis(phenylmelhylene)dianiline ¹ (2.02 g, 5 mmol) for 1 h at 75°C gave after chromatography (PFJElOAc 4:1) the tide acetylene (30%): mp 140-

143°C (cyclohexane); ^! HNMR (200 MHz, CDC1 ₃ ) δ 5.74 (s, 2H, CH ₂ ), 7.05-7.10 (m, 4H), 7.30-7.35 (m, 6H), 7.45-7.52 (m, 8H); ¹³ C NMR (300 MHz, CDC1 ₃ ) δ 88.58 (acetylenic C), 88.97 (acetylenic C), 90.70, 116.36, 117.41, 123.36, 128.08, 128.31, 131.48, 133.09, 156.72; IR (CDC1 ₃ ) 3062 (w), 2978 (w), 2911 (w), 2217 (w, acetylenic stretch), 1599, 1573 (w), 1509, 1443 (w), 1414 (w), 1314 (w), 1279

(w), 1233, 1209 (s), 1175, 1137 (w), 1103 (w), 1014, 836 cm ^"1 . MS (El) m/e 400 (M ⁺ , 64), 207 (100), 194 (18.7), 177 (83.7), 165 (24.3), 151 (27.0). Prepared as described previously: Paventi, M.; Hay, A. S. Synthesis 1990, 878. Example 43. 2-(2-Phenylethynyl)furan. A procedure similar to Example 16 but widi 2-(N- phenylaminomedιylidine)-furan (0.86 g, 0.005 mol) and (phenylmedιy)-lH- benzotriazole (1.05 g,0.005 mol) gave after workup and chromatography (PE/ EtOAc 4:1) an oil (90 %, 98.5% pure) (lit. ¹ oil bp 74 °C/0.1 mm Hg) which dark¬ ened on standing: ^l H NMR (270 MHz, CDC1 ₃ ) δ 6.61 (dd, J=3 ₄ 3.3, ₂₃ 1.98 Hz, IH, C3H), 6.855 (d, IH, C4H), 7.52-7.55 (m, 3H, phenyl), 7.616 (d, IH, C2H), 7.71 (m, 2H, phenyl); ¹³ C NMR (270 MHz, CDC1 ₃ ) δ 79.38 (C£(C ₄ H ₄ 0)), 93.22 (Ph£C), 111.03 (C4), 115.19 (C3), 122.25 (Cl'), 128.35 (C3'), 128.65 (C4 ¹ ), 131.38 (C2'), 137.12 (C2), 143.59 (C5); MS (El) m/e 168 (M ⁺ , lOQ), 139 (96.8). ⁱ Teitei, T.; Collin, P. J.; Sasse, W. H. F. Aust. J. Chem. 1972, 25, 171. Example 44.

3-(2-Phenyletiιynyl)pyridine. A procedure similar to Example 16 but widi 3-(N- phenylaminomedιylidine)-pyridine (0.911 g, 0.005 mol) and (phenylmethy)-lH- benzotriazole (1.05 g,0.005 mol) gave after workup and chromatography (PE/ EtOAc 4:1) and treaunent with boiling PE white needles (80 %): mp 47-48 °C (PE) (Ut. ¹ mp 47-48.5 °C, acetylenic stretch 2200 cm" ¹ ); MS (El) m/e 179 (M ⁺ , 100), 126 (21.7). Castro, C. E.; Gaughan, E. ; Owsley, D. C. /. Org. Chem. 1966, 31, 4071.

V. Synthesis of Indoles

Example 45. l-Phenyl-2-(4-fluorophenyl)-lH-indoIe. A solution of (2-fluorophenyl)methyl- lH-benzotriazole (1.13 g, 5 mmol) and N-[(4- fluorophenyl)med ylidine]benzenamine (.996 g, 5 mmol) in DMF (7 mL) was stirred into potassium t-butoxide (1.68 g, 15 mmol) in DMF (18 mL) preheated to

75 °C. The reaction monitore by ΗPLC showed completion upon mixing. After 11 minutes the DMF solution was poured in ice-cold Η ₂ 0 ( 75 mL) extracted with CHC13 (3 x 50 mL) and the solvent was evaporated. Chromatography first using PE as eluted l-(4-fluorophenylethynyl)[2-fluorobenzene] {vide infra) then the elu- 0 ant was changed to PE/EtOAc 97:3 eluting the title indole (40 %) : mp 126-128 °C (MeOH); ^l H NMR (200 MHz, CDC1 ₃ ) δ 6.77 (s, IH, C3H), 6.94 (t, J=8.7 Hz, 2H, phenic H), 7.16-7.48 (m, 10H), 7.66-7.72 (m, IH); MS (El) m/e 287 (M ⁺ , 100).

VI. Polymer Synthesis

Example 46

Poly(phenylene ether yne) from BPA. A mixture of 4,4'-

(l-Methylethylidene)bisphenol (BPA) (1.141 g, 5 mmol), 4,4'- » difluorodiphenylacelylene (1.071 g, 5 mmol) and anhydrous K2CO3 (0.9 g, 0 mmol) in toluene (10 mL) and N-methylpyrrolidone (NMP) (14 mL) was stirred and heated to the reflux temperature of toluene azeotropically removing the water for 5 hours under a slow stream of N ₂ . The temperature was allowed to increase to 180 °C over a period of 5 hours allowing for the removal of toluene and NMP (4 mL). The dark mixture was then allowed to stir for an additional 10 hours when 5 an aliquot flooded in MeOH precipitated high molecular weight polymer. The or- ganics were cooled, filtered Uirough celite, precipitated (MeOH),and dissolved in CHC1 ₃ , filtered and reprecipilated (MeOH), washed (H ₂ 0) and dried to yield 1.57 g of the title polymer : Tg=163 °C exotherm maximum 398 °C (temperature

ramped at 20 °C/min), ηiaii 0.69 dL/g (TCE, 25.4 °C), Mw=54400 Mn=23300. Af¬ ter a second scan d ere was no disccmable glass transition temperature indicating diat the polymer is now highly crosslinked. After heating die polymer is also now completely insoluble in all solvents.

Example 47

Poly(pheπylene ether yne) from 4,4'~difluorodiphenylacetylene and bis(4- hydroxypheπyI)-9,9-fluoreπe

4,4'-Difluorodiphenylacetylene (2.1422 g, 0.01000 mol), bis(4-hydroxyphenyl)-

9,9-fluorene (3.50416 g, 0.01000 mol), potassium carbonate (1.52 g, 0.0110 mol) NMP (28 mL) and toluene (20 mL) were healed at 140 °C for lh with removal of water with a Dean-Stark trap under a slow stream of nitrogen. The temperature was raised to 195°C by bleeding toluene from d e system and maintaining this temperature for 4.5h. Healing was discontinued, NMP (15 mL) was added to the hot polymer mixture. This mixture was tiien added dropwise to a fast-stirring MeOH H20 (600 mL:200 mL) mixture. The resulting precipitated polymer beads were suction-filtered, washed with water and MeOH and air-dried for lh. The ma¬ terial was dissolved in CHC13 (200 mL) and filtered through a bed of MgS04 (.5 cm) and celite (4 cm) in a 150 mL fritted funnel and washed widi CHC13 (200 mL). The volume of the filtrate was reduced to 100 mL and the tide polymer was recovered by dropwise addition of this chloroform solution into MeOH (500 mL). The beads were filtered and air-dried over tiiree days to give a quantitative yield of die title polymer, Tg=263 °C exotherm maximum 388 °C (temperature ramped at 20 °C/min). After a second scan tiiere was no discernable glass transition tem¬ perature indicating diat the polymer is now highly crosslinked. After heating d e

polymer is also now completely insoluble in all solvents.

VII. Copolymer Synthesis

The following copolymers were synthesized as in Example 43 using the molar amounts of 4,4'-difluorodiphenylacetylene and 4,4-dichlorodiphenylsulfone shown in Table 2.

Table 2. Properties of Copolymers