A synthesis of simple 4,4-disubstituted tetrahydroisoquinolines by cyclization of .ALPHA.,.ALPHA.-disubstituted phenylacetamides.
作者:SHINZO KANO、TSUTOMU YOKOMATSU、YOKO YUASA、SHIROSHI SHIBUYA
DOI:10.1248/cpb.33.340
日期:——
Cyclization of N-methyl-3, 4-dimethoxyphenylacetamide (1) with paraformaldehyde in formic acid afforded 6, 7-dimethoxy-3-isochromanone (2b). In contrast, the same reaction of α, α-disubstituted phenylacetamides (5a, b, d) gave the corresponding 4, 4-disubstituted isoquinolin-3-ones (7a-c). However, the α-allylphenylacetamide (5c) gave the azepinone (8) as the main product. On the other hand, the carbamate (6e) afforded the 4-allylisoquinoline (10).
N-甲基-3, 4-二甲氧基苯乙酰胺(1)与多聚甲醛在甲酸中反应,得到6, 7-二甲氧基-3-异香豆素(2b)。相比之下,α, α-二取代的苯乙酰胺(5a, b, d)的同种反应则生成相应的4, 4-二取代异喹啉-3-酮(7a-c)。然而,α-烯丙基苯乙酰胺(5c)则主要生成氮杂环酮(8)。另一方面,氨基甲酸酯(6e)则生成4-烯丙基异喹啉(10)。