| 摘要 |
PURPOSE:To carry out reaction in the presence of a noble metal catalyst in a diacyl ester of (poly)ethylene glycol, etc., as a reaction solvent in dehydrogenating a 4-oxo-4,5,6,7-tetrahydroindole to afford the titled substance. CONSTITUTION:A compound expressed by formula I (R<1> and R<2> are H, carboxyl, alkyl, etc.; R<3>-R<5> are H or lower alkyl) is dehydrogenated to give a compound expressed by formula II. In the process, a monoacyl ester of (poly)ethylene glycol monoalkyl ether expressed by formula III (R<6> and R<7> are 1-4C alkyl; n is 1, 2 or 3) or a diacyl ester of (poly)ethylene glycol expressed by formula IV is used as a reaction solvent to carry out the reaction in the presence of a noble metal catalyst, e.g. Pd or Pt-C powder, at 100-250 deg.C, preferably 150 deg.C - the boiling point of the solvent for 7-15hr. EFFECT:Since the above-mentioned solvent has improved solvency, the aimed substance is obtained in high yield in a short time. The rate of reaction of the raw material is high and the solvent is inexpensive. |
