Synthesis of Thiochromen-4-one-annelated Heterocycles: Regioselective Cyclization of 3-Hydroxy-2-cyclohex-2′-enylthiochromen-4-one
作者:K. C. Majumdar、B. Roy
DOI:10.1081/scc-120015569
日期:2003.3
yield which on dehydrogenation with palladized charcoal gave benzofuro[3,2-b]thiochromen-6-one (6). Substrate 4 on reaction with hexamethylenetetramine hydrotribromide gave a mixture of three products, linearly cyclized heterocycle 10 (35%), bicyclic heterocyclic 8 (15%), and dibromide 9 (20%). The same reaction when conducted with pyridine hydrotribromide furnished only the dibromide 9 which was then cyclized
摘要 2-Cyclohex-2'-enyl-3-hydroxythiochromen-4-one (4) 通过 3-cyclohex-2'-enyloxythiochromen-4-one 的热 [3,3] sigmatropic 重排以 80% 的产率合成( 3)。在回流苯中用氯化钯(双苯甲腈)处理 4 得到线性环化产物四氢苯并呋喃 [3,2-b] thiochromen-6-one (5),收率 98%,用钯炭脱氢得到苯并呋喃 [3,2- b]thiochromen-6-one (6)。底物 4 与六亚甲基四胺氢三溴化物反应得到三种产物的混合物,直链环化杂环 10 (35%)、双环杂环 8 (15%) 和二溴化物 9 (20%)。用吡啶氢三溴化物进行的相同反应仅提供二溴化物 9,然后将其在丙酮-碳酸钾中环化,以 85% 的产率得到双环化合物 8。二溴化物9通过与二苯醚中的钯炭一起加热而