Method of making intermediates for camptothecin and its analogs

Abstract

Disclosed are new methods of making camptothecin and camptothecin analogs defined by Formula I: ##STR1## wherein R is loweralkyl; R.sub.1 is H, loweralkyl, loweralkoxy, or halo; and R.sub.2, R.sub.3, R.sub.4 and R.sub.5 are each independently H, amino, hydroxy, loweralkyl, loweralkoxy, loweralkylthiol, di(loweralkyl)amino, cyano, methylenedioxy, formyl, nitro, halo, trifluoromethyl, aminomethyl, azido, amido, hydrazino, or any of the twenty standard amino acids bonded to the A ring via the amino-nitrogen atom. The methods comprise cyclizing a compound of Formula IV: ##STR2## wherein X is Br or I, and Y is H, by an Aryl-to-Aryl free radical coupling reaction to yield a compound of Formula I. Compounds of Formula IV are made by alkylating a compound of Formula III: ##STR3## wherein R is loweralkyl and Y is H with a compound of Formula II-x: ##STR4## wherein X is a Br or I and V is hydroxy, by a Mitsunobu reaction to yield the compound of Formula IV.

Dependencies are inferred from the claim text.