Synthesis and autoxidation of new tetracyclic 9H,10H-indolizino[1,2-b]indole-1-ones.
The new tetracyclic 9H,10H-indolizino[1,2-b]indole-1-one derivatives (7a-d, 7ea, 7eb) have been synthesized by modified Fischer indole synthesis from the enol ether of 2,5-dihydroxy-7-methyl-6-cyano-indolizine (3) and arylhydrazines (4a-g). Attempted N-methylation of 7a-d produced a series of autoxidized products including 10-hydroperoxy-1-methoxyindolizino[1,2-b]indole (9a-d) as the major product accompanied with methylperoxides (10a-d and 11a-d) and 2-formyl-3-(pyridine-2-yl)indole (12a, 12c) derivatives as the minor products. A plausible mechanism of the autoxidation is postulated based on the isolation of some intermediates. The reaction is thought to proceed through azaenolate/enamine intermediates following a novel type of autoxidation.
Bhattacharya
G
G
Laboratory of Bioorganic Chemistry, Institute of Biomedical Sciences, Academia Sinica, Taipei 11529, Taiwan.
Su
T L
TL
Chia
C M
CM
Chen
K T
KT
D007202:Indicators and Reagents; D007211:Indoles / Q000138:chemical synthesis* / Q000737:chemistry*; D007212:Indolizines / Q000138:chemical synthesis* / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D013058:Mass Spectrometry; D015394:Molecular Structure; D010084:Oxidation-Reduction
D007202:Indicators and Reagents; D007211:Indoles; D007212:Indolizines