Synthesis and ring closure reactions of pyrido[3,2,1-<i>jk</i>]carbazol-6-ones

Abstract

4-Hydroxy-5-phenylpyrido[3,2,1-jk]carbazol-6-ones (4, 5), which were obtained from carbazoles 1 and malonates 2 or 3, were converted to reactive intermediates such as 4-chlorides 9 or 4-tosylates 10, which gave in turn 4-azido-5-phenyl derivatives 11. 5-Alkyl-4-azides 11 were not obtained in this manner; however a new one-pot azidation reaction was developed starting from 4-hydroxy derivatives 4 which gave azides 11 in good yields. 4-Azido-5-phenyl derivative 11f cyclized on thermolysis to the indole 12. The thermal behaviour of the azides 11 was studied by thermoanalytical methods (DSC).