Einfache Herstellung von zum Teil in 5,6-Stellung anellierten 2-Amino-thieno [2,3-<i>d</i>][1,3]thiazin-4-onen
作者:Siegfried Leistner、Michael Gütschow、Günther Wagner
DOI:10.1055/s-1987-33428
日期:——
The Facile Synthesis of 2-Aminothieno[2,3-d][1,3]thiazin-4-ones, in Some Cases 5,6-Anellated The cyclization of ethyl 2-thioureidothiophene-3-carboxylates is known to give 2-thioxothieno[2,3-d]pyrimidin-4-ones not only under basic conditions but also upon treatment with ethanolic hydrochloric acid. On the other hand, we have found that ethyl 2-thioureidothiophene-3-carboxylates 1 on treatment with concentrated sulphuric acid, polyphosphoric acid or anhydrous perchloric acid undergo cyclocondensation to give 2-aminothieno[2,3-d][1,3]thiazin-4-ones 2a-2r. Reaction of 2 with phosphorus (V) sulfide yielded the thieno[2,3-d][1,3]thiazine-4-thiones 3b and 3c; ring cleavage of the aminothienothiazinones 2k, 2m, 2n with diluted sodium hydroxide gave the 2-thioureidothiophene-3-carboxylic acids 5k, 5m, 5n, respectively.
简单合成2-氨基噻烯[2,3-d][1,3]噻唑-4-酮,有些情况下为5,6-联环化已知乙基2-硫脲基噻吩-3-羧酸酯在碱性条件下及与醇酸盐酸处理时,均可环化生成2-硫代噻烯[2,3-d]嘧啶-4-酮。另一方面,我们发现,乙基2-硫脲基噻吩-3-羧酸酯1与浓硫酸、聚磷酸或无水过氯酸处理时,会发生环缩合,生成2-氨基噻烯[2,3-d][1,3]噻唑-4-酮2a-2r。与磷(V)硫化物反应后,得到噻烯[2,3-d][1,3]噻唑-4-硫酮3b和3c;用稀氢氧化钠处理氨基噻烯噻唑酮2k、2m、2n,则分别得到2-硫脲基噻吩-3-羧酸5k、5m、5n。