N-Benzoylthioamides (1) react with hydrazines and hydroxylamine to form lH-l,2,4triazoIes and 1,2,4-oxadiazoles, respectively. A similar treatment of the S-methyl derivatives of 1 with amidines leads to 1,3,5-triazines. Ethyl N-benzoylthiocarbamate undergoes analogous reactions to yield the corresponding e thoxyheterocycles. j . Heterocyclic Chern., 18, 1197 (1981).The reactions of N-ethoxycarbonylthioamides with hydrazines, hydroxylamines, and amidines involve nucleophilic attack at both thiocarbonyl and carbonyl groups and proceed with loss of hydrogen sulfide and ethanol to form substituted 1,2,4triazolones, 1,2,4oxadiazolones, and 1,3,5-triazinones, respectively (1,2). Analogous reactions of N-acylthioamides can be expected to result in loss of hydrogen sulfide and water and to yield the corresponding aromatic triazoles, oxadiazoles, and triazines in a straightforward manner. Surprisingly, very few examples of such reactions can be found in the literature. Thus, treatment of ethyl N-benzoylthiocarbamate with phenylhydrazine has been reported to lead to 3-ethoxy-l,5-diphenyl-lH-l,2,4triazole (3). More recently, the reaction of N-acetylthiobenzamide with phenylhydrazine was found to yield 5-methyl-1,3-diphenyl-lH-l,2,4triazole (4). N-Acylthioamides have been prepared by the Friedel-Crafts reaction between toluene and benzoyl isothiocyanate (5), by acylation of thioamides (4), and by lowtemperature treatment of acyl isothiocyanates with Grignard reagents (6). In our hands, the Friedel-Crafts method gave unsatisfactory yields (5-10% of purified product), but the low temperature reactions of benzoyl isothiocyanate with arylmagnesium bromides allowed the preparation of N-benzoylthioamides in reasonable yields (la, 48%; lb, 48%; lc, 35%).We have found that N-benzoylthioamides (la-c) react readily with hydrazine to form 3,5-diaryl-lH-l,2,4triazoles (2a-c) in very good yields. The structures assigned to these products are supported by spectral data (ir, nmr), as well as by the previously reported melting points for, the known 2a and 2b. Analogous reactions of la-c with methylhydrazine, benzylhydrazine, and phenylhydrazine lead to the corresponding 1,3,5-trisubstituted lH-1,2,4 triazoles (3a-c, 4a-c, and 5a-c) in generally good yield.However, for such monosubstituted hydrazines, the possibility exists that reaction with 1 may occur in either of two orientations to yield either triazoles 3-5, or their isomers 6, or both. The proposed product structure (3-5) assumes attack on the thiocarbonyl of 1 by the primary amino group of the monosubstituted hydrazines and is supported by the following observations. (a) Treatment of 1197 II II SO-s R = Me Ph/C\NH/C\ 4 0 -6 R = PhCH2 So-d R = Ph l a Y = Ph I b Y 4-CH3CgHq Ic Y = 4-i-PrC6H4 I d Y = EtO / \ 1.Y = E12N 3) R-CbNH 'NH2 N A ' N P h k N A R l o -d , f R = Ph Of Y I M e N-benzoyl-4isopropylthiobenzamide (lc) with aniline results in evolution of hydrogen sulfide and formation of N-benzoyl-N'-phenyl-4isopropylbenzamidine (9). (b) As mentioned earlier, N-acetylthiobenzamide is ...

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N‐Benzoylthioamide (I) kondensieren mit den Hydrazinen (II) zu den Triazolen (III); mit Hydroxylamin entstehen die Oxadiazole (IV).

Das Acylisothiocyanat (I) wird mit Aminen in Thioharnstoffe (II) und mit Alkoholen in Thiocarbamate (III) übergeführt.