OPTICAL ROTATORY DISPERSION OF INDOLINE ALKALOIDS WITH KETO GROUPS

The optical rotatory dispersion curves of a series of indolines, N(a)‐acetyl‐indolines and N(a)‐methoxycarbonyl‐indolines containing keto groups have been measured. It has been shown that the absolute stereochemistry of N(a)‐acetyl‐indolines containing keto groups can still be determined from the character of the Cotton Effect due to the aromatic chromophore, the ketone Cotton Effect however being more difficult to interpret. The use of N(a)‐methoxycarbonyl‐indoline and indoline chromophores is dangerous due to the complex nature of the Cotton Effect of the former and the overlapping of that of the latter with the ketone Cotton Effect. Copyright © 1968 Verlag GmbH & Co. KGaA, Weinheim