Acyl and Sulfonyl Derivatives of 3,5-Diamino-1-R-1,2,4-triazoles

Abstract

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

Molecular and crystal structure of 5-amino-3-(N-p-methylbenzoyl-N-p-toluenesulfonyl)amino-1-phenyl-1,2,4-triazole

“…The X-ray structural analysis data therefore confirmed the proposed direction of the acylation reaction of 3-acylamino-5-amino-and 5-amino-3-sulfonylamino-1-R-1,2,4-triazoles [4]. Acylation of the substituted 3-amino group initially is confirmed by the formation of 5-amino-3-(N,N-diacyl)amino-or 5-amino-3-(N-acyl-N-sulfonyl)amino-1-R-1,2,4-triazoles, which are then rearranged to the thermodynamically more stable 3,5-diacylamino-or 5-acylamino-3-sulfonylamino-1-R-1,2,4-triazoles.…”

“…However the spectral data presented in [4] were not able completely to exclude the possibility of isomeric structures of this compound, such as structures 3 and 4. Since the structure of the obtained compound enables the special features of the acylation reactions of 3-acylamino-5-amino-and 5-amino-3-sulfonylamino-1-R-1,2,4-triazoles to be understood [4], we have carried out an X-ray structural analysis of it. According to the data of X-ray structural analysis (Figs.…”

“…On acylating 5-amino-1-phenyl-3-p-toluenesulfonylamino-1,2,4-triazole (1) with p-methylbenzoyl chloride in acetonitrile in the presence of pyridine a compound is obtained which, on the basis of data of elemental analysis, IR and NMR spectroscopy, was assigned the structure of 5-amino-3-(N-p-methylbenzoyl-N-p-toluenesulfonyl)amino-1-phenyl-1,2,4-triazole (2) [4]. However the spectral data presented in [4] were not able completely to exclude the possibility of isomeric structures of this compound, such as structures 3 and 4. Since the structure of the obtained compound enables the special features of the acylation reactions of 3-acylamino-5-amino-and 5-amino-3-sulfonylamino-1-R-1,2,4-triazoles to be understood [4], we have carried out an X-ray structural analysis of it.…”

“…The N (4) and N (5) atoms have a trigonal pyramidal configuration (sum of valence angles 336.2 and 350.5° respectively). The deviation of the N (4) atom from the plane of the triazole ring is 0.014(3) Å, while the N (5) atom deviates by 0.091(3) Å, probably as a result of the reduced intramolecular contact C (2) ···C (9) of 3.05 Å and the shortened contacts at N (1) ···C (9) of 3.18 and N (3) ···C (4) 3.19 Å.…”

Synthesis, structure and some reactions of 4a',5′,6′,7′,8′,8a'‐hexahydro‐4′H‐spiro[cyclohexane‐1,9′‐[1,2,4]triazolo[5,1‐b]‐quinazolines]

“…On the whole, the obtained results show, that in the acylation reactions the compounds 4c,d are similar to 1-substitured 5-amino-1,2,4-triazoles [32], whereas the compound 4b is analogous to 1-substitured 3,5-diamino-1,2,4-triazoles [33][34][35]. temperature.…”