Efficient Iminophosphorane-Mediated Preparation of Benzofuro[3,2-d]pyrimidin-4(3H)-ones and Unexpected Ring Opening Products
作者:Yang-Gen Hu、Ming-Guo Liu、Ming-Wu Ding
DOI:10.1002/hlca.200890090
日期:2008.5
reacted with secondary amines, phenols or alcohols in the presence of catalytic amounts of K2CO3 or sodium alkoxide to give 2-substituted benzofuro[3,2-d]pyrimidin-4(3H)-ones 6. However, when 2,2′-iminobis[ethanol] was used, the unexpected ring opening product 7 was formed instead of 6. Reaction of 4 with primary amines RNH2 (R=Et, Pr, Bu, etc.) gave guanidine intermediates 8, which were further treated
由亚氨基磷烷3与芳族异氰酸酯的氮杂-维蒂希反应获得的碳二亚胺4,在催化量的K 2 CO 3或醇钠的存在下,与仲胺,酚或醇反应,得到2-取代的苯并呋喃[3,2- d ]嘧啶-4(3 H)-ones 6。然而,当使用2,2'-亚氨基双[乙醇]时,形成了意想不到的开环产物7而不是6。的反应4与伯胺RNH 2(R =乙基,丙基,卜,等等),得到胍中间体8将其进一步用EtONa处理,通过碱催化的环化反应仅产生一种区域异构体9。但是,在不存在EtONa的情况下,通过自发环化8使用NH 3或“小”胺RNH 2(R = Me,NH 2),则获得了另一个区域异构体11。