The Diels-Alder reaction of 1-cyclohexenecarbaldehyde N,N-dimethylhydrazone with juglone
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Date
1997
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Abstract
The synthesis of 1-cyclohexenecarbaldehyde N,N-dimethylhydrazone 7 from cyclohexanecarbaldehyde by using a three step sequence is reported. The Diels-Alder reaction of juglone 5 with azadiene 7 provides hexahydrobenzo[b]phenantridine 14a in 55% tetrahydrobenzo[b]phenantridines 15a and 15b. Angular tetracyclic quinone 15a was formed in 47% yield by caning out the cycloaddition of 5 and 7 in the presence of oxygen. Under this oxidant condition compound 15a undergoes partial oxidation to tetracyclic quinone 17.