| 摘要 |
<p>PURPOSE:To obtain the subject compound useful as a synthetic intermediate for physiologically active pharmaceuticals and natural substances in high yield by stirring a specific indole compound in the presence of an acid catalyst under heating. CONSTITUTION:The objective compound of formula II (e.g. 4-keto-tetrahydro-beta- carboline) is produced by stirring an indole compound of formula I (R<1> is H or lower alkyl; R<2> is H, formyl or benzoyl; R<3> is lower alkyl) [e.g. N-(indol-2-yl) methyl-N-formylaminoacetic acid ethyl ester] in the presence of an acid catalyst (e.g. polyphosphoric acid and p-toluenesulfonic acid) under heating at e.g. 60-80 deg.C. The indole compound of formula I used as a starting raw material can be produced e.g. by reducing and oxidizing an indole-2-carboxylic acid of formula III, reacting the resultant indole-2-aldehyde of formula IV with a glycine ester, reducing the product and reacting with ethyl formate, etc.</p> |
