Water/Alkali-Catalyzed Reactions of Azides with 2-Cyanothioacetamides. Eco-Friendly Synthesis of Monocyclic and Bicyclic 1,2,3-Thiadiazole-4-carbimidamides and 5-Amino-1,2,3-triazole-4-carbothioamidesстатьяИсследовательская статья
Статья опубликована в высокорейтинговом журнале
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Дата последнего поиска статьи во внешних источниках: 20 декабря 2019 г.
Аннотация:The reactions of thioamides with azides in water were studied. It was reliably shown that the reaction of 2-
cyanothioacetamides 1 with various types of azides 2 in water in the presence of alkali presents an efficient, general, one-step,
atom-economic, and eco-friendly method for the synthesis of 1,2,3-thiadiazol-4-carbimidamides 5 and 1,2,3-triazole-4-
carbothioamides 4. This method can be extended to the one-pot reaction of sulfonyl chlorides and 6-chloropyrimidines 2′o with
sodium azide, leading to final products in higher yields, that is, avoiding the isolation of unsafe sulfonyl azides. The method was
furthermore applied to the reaction of N,N′-bis-(2-cyanothiocarbonyl)pyrazine 1h with sulfonyl azides to afford bicyclic 1,2,3-
thiadiazoles 8 and 1,2,3-triazoles 9 connected via a 1,1′-piperazinyl linker. 2-Cyanothioacetamides 1 were also shown to react
with aromatic azides in water in the presence of alkali to afford 1-aryl-5-amino-1,2,3-triazole-4-carbothioamides 11. In contrast
to aromatic azides and similarly to sulfonyl azides, 6-azidopyrimidine-2,4-diones 2o−q react with cyanothioacetamides to form
N-pyrimidin-6-yl-5-dialkylamino-1,2,3-thiadiazole-4-N-l-carbimidamides 12. A mechanism was proposed to rationalize the role
of water in changing the reactivity of azides toward 2-cyanothioacetamides.