Synthesis and reactivity of spiro[1,3,4-thiadiazoline-2,4′-thioflavans] and analogues
作者:László Somogyi
DOI:10.1002/jhet.25
日期:2009.5
3-acetylspiro[1,3,4-oxa(thia)-diazoline-2,4′-thioflavans] with trans O(1) or S(1) and Ph(2′eq) under acetylating conditions. Conjugation between the ethylenic bond and sp2 C(4) in thioflavones encumber both the formation of (thio)acylhydrazones and their subsequent spirocyclization. On the other hand, subsequent dehydrogenation of the thiopyran moiety of spiro compounds results in formation of sp2 C(4)