Reactions of Malonothioamide Derivatives with Azides*

Abstract

The reactions of primary and tertiary malonothioamides with aryl and sulfonyl azides can take place in three directions, depending on the nature of the thioamides and azides. Ethoxycarbonylthioacetamide reacts with aryl azides with the formation of ethyl 5-amino-1-aryl-1,2,3-triazole-4-carboxylates. In reaction with aryl azides tertiary thioamides of cyanoacetic acid form 5-amino-1-aryl-1,2,3-triazole-4-carbothioamides, and in reaction with tosyl azide they form 5-amino-4-carboxamidino-1,2,3-thiadiazoles. Hypothetical mechanisms for the transformations are discussed.

Progress in intermolecular and intramolecular reactions of thioamides with diazo compounds and azides

“…Because the cyclization of diazothiocarbonyl compounds is straightforward to 1,2,3-thiadiazoles, the methods of the synthesis of the latter are based on the syntheses involving unstable diazothiones [34,35]. The three general methods leading to compounds 48 include the diazo group transfer [34,35,38] Recently, we have prepared a series of 5-sulfonylamido-1,2,3triazoles as sodium salts 52 by reaction of tertiary 2-cyanothioacetamides 56 with various arylsulfonyl azides in very good yields (Schemes 14 and 15) [42,43]. The proposed mechanism involves the cyclization of diazo compounds 47 bearing thiocarbonyl and imidamide groups to triazoles 52.…”

Reactions of Thioacetamide Derivatives with Sulfonyl Azides: An Approach to Active‐Methylene N‐Sulfonylacetamidines

“…We started our experiments by studying the reaction of tosyl azide ( 9b ) with cyanothioacetamide 8a (Scheme ). Thioamide 8a was found to be unreactive when we used ethanol at room temperature, under the conditions of Aswad 17. We also found that the reaction of thioamide 8a with tosyl azide in pyridine, according to Zelenskaya et al,18 led to an oily brown residue containing traces of cyanoacetamidine 10a .…”

“…Two papers, apart from ours,17 have been published on the reactions of thioamides with sulfonyl azides. The first report, from O. V. Zelenskaya et al, deals with the preparation of sulfonyl amidines by the reaction of thioamides with tosyl azide under relatively harsh conditions: heating at 90–100 °C in pyridine for 5 h 18.…”

“…The reaction of mesyl and benzenesulfonyl azides with thioacetamides 3 , in which the methylene group is not activated, takes a different direction, leading to the formation of acetamidines 4 16. Recently, we discovered that tosyl azide can react with N , N ‐disubstituted cyanothiocetamide 5 in the presence of triethylamine to give 4‐tosylamidino‐1,2,3‐thiadiazoles 6 and 7 ; in this reaction it acts as the source of both diazo and sulfonyl imino groups 17. Thus, sulfonyl azides could be donors of diazo and sulfonyl imino fragments in reactions of thioamides with sulfonyl azides.…”

Metal‐ and Photoredox‐Catalyst Free Unified Approach for the Synthesis of Azole‐Fused Quinolines via tert‐Butyl Nitrite‐Mediated Regioselective Annulation

“…Having assessed the scope of reaction with differently substituted pyrazoles, we diverted our attention to other azole systems. In this context, N ‐phenyl 1,2,3‐triazoles 5 a – b were prepared [24] and subjected to reaction with alkyne 2 a (Scheme 4). Gratifyingly, the reactions were successful to furnish the 1,2,3‐triazolo[1,5‐ a ]‐quinolines 6 a – 6 b in 64–66% yields.…”