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Acylation of 3,5-diamino-1,2,4-triazole with anhydrides and chlorides of alkane-and arenecarboxylic acids and arenesulfonyl chlorides in aqueous solutions and under phase-transfer catalysis was studied.Acyl, aroyl, and arenesulfonyl derivatives of 3,5-diamino-1,2,4-triazoles are used as intermediates for preparing nitro and azido derivatives of 1,2,4-triazoles [133], and also drugs and herbicides [4 37]. The most general route to acyl derivatives of 3,5-diamino-1,2,4-triazole is acylation of 3,5-diamino-1,2,4-triazole I, which can yield mono-, di-, and triacetyl derivatives depending on the reaction conditions [1, 4, 83 10]. However, triazole I is expensive, despite the fact that it is prepared from available substances: dicyanodiamide II and hydrazine [11]. The high cost of I is due to its difficult isolation from reaction mixtures. Our previous studies [12,13] showed that some derivatives of I can be prepared from dicyanodiamide and hydrazine without isolation of I.In this study we developed a procedure for preparing 1-acyl-, 1-aroyl-, and 1-arenesulfonyl-3,5-diamino-1,2,4-triazoles by acylation of products of the reaction of nitrile II with hydrazine without isolation of I:

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Depending on the reaction conditions, acylation of unsubstituted 3,5-diamino-1,2,4-triazole leads to the formation of acylation products at both the ring N (1) atom and at the exocyclic amino groups [1][2][3][4]. The direction of acylation of 3,5-diamino-1-R-1,2,4-triazole 1 has not been established precisely up to the present time. It has been shown that brief heating of 3,5-diamino-1-phenyl-1,2,4-triazole (1a ) with acetic anhydride leads to the formation of a monoacetyl derivative, but refluxing in an excess of anhydride leads to the formation of a diacetyl derivative, the structures of which were not determined [5]. The product of the interaction of 1a with acetoacetic ester was assigned the structure of 1-acetoacetyl-3,5-diimino-2-phenyl-1,2,4-triazole [6], but with cyanates and thiocyanates the carbamoyl and thiocarbamoyl derivatives at one of the exocyclic amino groups were formed [7]. The problem of the reaction direction remained open.The aim of the present work is the determination of the direction of acylation and sulfonation reactions of 3,5-diamino-1-R-1,2,4-triazoles 1a,b.It was established that the interaction of compounds 1a,b with an equimolar quantity of anhydrides 2a-c, carboxylic acid chlorides 2d-f,i, and sulfonyl chlorides 2g,h proceeds regioselectively and gives 3-acylamino-5-amino-1-R-1,2,4-triazoles 3a-f,i,j and 5-amino-3-sulfonylamino-1-R-1,2,4-triazoles 3g,h,k in good yield (Scheme 1, Table 1).According to the data of [8,9] the 1 H NMR spectra of 3,5-diamino-1-R-1,2,4-triazoles in DMSO-d 6 have broad discernible singlets for the protons of the 3-NH 2 and 5-NH 2 groups in the region of 5 and 6 ppm respectively. The chemical shifts of 5.08 and 4.75 (3-NH 2 ), 6.15 and 6.05 ppm (5-NH 2 ) correspond to the protons of the amino groups of compounds 1a,b. In the 1 H NMR spectra of compounds 3a-k the 3-NH 2 signal has disappeared, but a signal for an amide proton appears at 9.8-12.5 ppm. The singlet of the 5-NH 2 protons is displaced a little towards low field and appears in the range 6.25-6.60 ppm (Table 2). These values of the __________________________________________________________________________________________ South