41266-81-3Relevant articles and documents
Switchable Synthesis of 4,5-Functionalized 1,2,3-Thiadiazoles and 1,2,3-Triazoles from 2-Cyanothioacetamides under Diazo Group Transfer Conditions
Filimonov, Valeriy O.,Dianova, Lidia N.,Galata, Kristina A.,Beryozkina, Tetyana V.,Novikov, Mikhail S.,Berseneva, Vera S.,Eltsov, Oleg S.,Lebedev, Albert T.,Slepukhin, Pavel A.,Bakulev, Vasiliy A.
, p. 4056 - 4071 (2017)
High yield solvent-base-controlled, transition metal-free synthesis of 4,5-functionalized 1,2,3-thiadiazoles and 1,2,3-triazoles from 2-cyanothioacetamides and sulfonyl azides is described. Under diazo transfer conditions in the presence of a base in an aprotic solvent 2-cyanothioacetamides operating as C-C-S building blocks produce 5-amino-4-cyano-1,2,3-thiadiazoles exclusively. The use of alkoxide/alcohol system completely switches the reaction course due to the change of one of the reaction centers in the 2-cyanothioacetamide (C-C-N building block) resulting in the formation of 5-sulfonamido-1,2,3-triazole-4-carbothioamide sodium salts as the only products. The latter serve as good precursors for 5-amino-1,2,3-thiadiazole-4-carboximidamides, the products of Cornforth-type rearrangement occurring in neutral protic medium or under acid conditions. According to DFT calculations (B3LYP/6-311+G(d,p)) the rearrangement proceeds via intermediate formation of a diazo compound, and can be catalyzed by acids via the protonation of oxygen atom of the sulfonamide group.
TWO DIRECTIONS OF CYCLISATION OF α-DIAZO-β-DITHIOAMIDES. NEW REARRANGEMENTS OF 1,2,3-TRIAZOLE-4-CARBOTHIAMIDES.
Bakulev, V. A.,Lebedev, A. T.,Dankova, E. F.,Mokrushin, V. S.,Petrosyan, V. S.
, p. 7329 - 7340 (2007/10/02)
The cyclization processes of 2-diazomalondithioamides, generated by five different methods, have been studied.The ambient character of the derivatives of 2-diazomalondithioamide is the cause of previously unknown rearrangements of 5-mercapto-1,2,3-triazole- and 5-amino-1,2,3-thiadiazole-4-N-R-carbothioamides to 5-N-R-amino-1,2,3-thiadiazole-4-carbothioamides.NMR 1H and 13C spectra and mass-spectra are presented for the series of 5-amino-1,2,3-thiadiazole derivatives.
