REACTION OF ACETYLENEDICARBOXYLIC ACIDS ESTERS WITH 4,5-DIHYDRO-1 H -PYRAZOLE-1-CARBOTHIOAMIDES AND 3,4,5,6-TETRAHYDRO-2 H -1,2,4-TRIAZEPINE-3-THIONES
The reactions of dimethyl acetylenecarboxylate with 3,4,5,6‑tetrahydro‑2 H ‑1,2,4‑triazepine‑3‑thiones and 4,5‑dihydro‑1 H ‑pyrazole‑1‑carbothioamides are convenient methods for the synthesis of 7,8‑dihydrothiazolo[3,2‑ b ][1,2,4]triazepin‑3‑ones derivatives and methyl esters of (2 Z )-[2-(4,5-dihydro-1 H -pyrazol-1-yl)-4-oxo-1,3-thiazol-5(4 H )-ylidene]acetic acids, respectively. The reaction of methyl propynoates with 4,5-dihydro-1 H -pyrazole-1-carbothioamides or with 5,5,7-trimethyl-2,4,5,6-tetrahydro-3H‑1,2,4‑triazepine‑3‑thione gives 2‑(4,5‑dihydro-1 H ‑pyrazol‑1‑yl)-4 H ‑1,3‑thiazin‑4‑ones. Authors: A. Danilkina, L. E. Mikhaylov, and B. A. Ivin English Translation in Chemistry of Heterocyclic Compounds , 2011, 47 (7), pp 886-900 http://link.springer.com/article/10.1007/s10593-011-0850-9