Acylation of 2-aminobenzenethiol with methyl chloroformate in pyridine gave dimethyl 2,2′-disulfanediylbis(2,1-phenylene)dicarbamate instead of expected methyl 2-suylfanylphenylcarbamate. Heating of the product with zinc dust in glacial acetic acid led to the formation of 1,3-benzothiazol-2(3H)-one. Alkylation of the latter with 1,2-dibromoethane and allyl bromide, as well as acylation with chloroacetyl chloride, afforded the corresponding 3-substituted derivatives. 3-[3-(Pyridin-2-yl)-4,5-dihydroisoxazol-5-ylmethyl]-1,3-benzothiazol-2(3H)-one was synthesized with high regioselectivity by 1,3-dipolar cycloaddition of 3-allyl-1,3-benzothiazol-2(3H)-one to pyridine-2-carbonitrile oxide generated from N-hydroxypyridine-2-carboximidoyl chloride hydrochloride by the action of triethylamine.Derivatives of 2-aminobenzenethiol are widely used in the synthesis of heterocyclic compounds [1, 2]. Acylation of 2-aminobenzenethiol is not selective, and the reaction direction depends on the conditions and the nature of acylating agent. It is known that acylation of 2-aminobenzenethiol with acid chlorides in the presence of bases yields 2-substituted 1,3-benzothiazoles [3] and that the reaction with chloroacetyl chloride in methylene chloride occurs exclusively at the nitrogen atom [4]. Acylation of 2-aminobenzenethiol with acetic and propionic anhydrides in aqueous medium in the presence of sodium hydrogen carbonate was accompanied by formation of 2-methyl-and 2-ethyl-1,3-benzothiazoles, respectively (in addition to the corresponding N-acyl derivatives) [5]. Ethyl 3-(4-oxo-2,3,4,5-tetrahydro-1,5-benzothiazepin-5-yl)propionate or N- [2-(carboxyethylsulfanyl)phenyl]-β-alanine were formed in the reaction of acrylic acid with 2-aminobenzenethiol, depending on the reactant ratio [6].We found that acylation of 2-aminobenzenethiol with methyl chloroformate in anhydrous pyridine gives dimethyl 2,2′-disulfanediylbis(2,1-phenylene)dicarbamate (I) instead of expected methyl 2-suylfanylphenylcarbamate (Scheme 1). Compound I was synthesized previously by acylation of 2,2′-disulfanediyldianiline with methyl chloroformate [7].The structure of disulfide I was confirmed by the IR, 1 H NMR, and mass spectra. The IR spectrum of I lacked absorption band at 2550 cm -1 , which is typical of stretching vibrations of SH group but contained absorption bands at 3380 and 1740 cm -1 due to stretching vibrations of NH and C=O groups in addition to absorption bands corresponding to vibrations of the benzene ring. No SH signal (δ 3.27 ppm [8]) was observed in the 1 H NMR spectrum of I. In the mass spectrum of compound I, ion peaks with m/z 364 [M] + and m/z 182 were present, which indicated the formation of disulfide structure.

Reactions of methyl(ethyl) N-(2-cyanophenyl)carbamates with sodium azide in dimethylformamide at 80-90°С in the presence of anhydrous CdCl 2 afforded the corresponding N-arylcarbamates with a 1,2,3,4-tetrazole fragment. The acylation of methyl N- [2-(1H-1,2,3,4-tetrazol-5-yl)phenyl]carbamate with acetic anhydride followed by the condensation of the obtained N-acyl derivative with thiophene-2-carbaldehyde in the KOH methanol solution led to the formation of methyl N- (2-{1-[3-(2-thienyl)-2-propenoyl]-1Н-1,2,3,4-tetrazol-5-yl}phenyl)carbamate. The reaction of cyclohexyl N-(4-aminophenyl)carbamate with а triethyl orthoformate and sodium azide in glacial AcOH yielded cyclohexyl N- [4-(1H-1,2,3,4-tetrazol-1-yl)phenyl]carbamate.Specific properties of the tetrazole ring consisting in its partial aromaticity and relatively high stability regardless the presence of four heteroatoms attract the interest to tetrazoles as objects of fundamental research [1]. They serve as semiproducts in the synthesis of versatile condensed, linearly connected, and spiro fused heterocycles.The tetrazole chemistry over the course of a century of its development is encompassed in several general reviews [2][3][4][5][6][7][8] and in a number of specialty surveys on 2-aryltetrazoles [9], tetrazolium salts [10], energetic tetrazoles [11], synthesis and reactions of lithium tetrazoles [12], acid-base properties [13], complex formation [14, 15], phase transfer catalysis [16], thermal transformations [17], analogy of thermal and mass spectrometric fragmentation [18], medical applications [19,20], and also on various kinds of tautomerism, some synthetic problems, and other issues.The growing world-wide interest in tetrazoles originates above all from the considerable success in manufacturing proceeding from 1-mono-, 1,5-and 2,5-disubstituted tetrazoles of a number of highly efficient drugs: antibiotics of cephalosporin series, cholesterol reducing, antihypertensive and antiviral medications, in particular, enzymes inhibitors of HIV/AIDS.Tetrazoles are also promising as analytical reagents, radioprotectors, herbicides, components of mixed fuels, pyrotechnic, explosive, and gas-generating compositions, they are exclusively important for synthetic chemistry in the preparation of various classes of compounds.We studied the possibility of the synthesis of 1Н-tetrazoles with phenylcarbamate fragment proceeding from ethyl(methyl) (2-cyanophenyl)carbamates I and II. Carbamate I in its turn was obtained by acylation of 2-aminobenzonitrile with methyl chloroformate in pyridine solution and compound II was prepared by the cleavage of О-acyl derivative of isatin oxime in the presence of ethanol [21]. The synthesis of 1Н-tetrazole derivatives III and IV was performed by heating a mixture of 1 equiv of carbamates cyano derivatives I and II with 2 equiv of sodium azide in DMF in the presence of anhydrous cadmium chloride at 80-90°С for 8 h [22] (Scheme 1).The structure of compounds III and IV was confirmed by IR, 1 Н NMR, and mass spectra, and of tetrazole III, add...

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Acylation of 2‐mercapto‐aniline (I) with chloroformate (II) affords unexpectedly disulfide (III).