Divergent Behavior of β‐Carbonyl‐Substituted 1H‐Benzo[f]chromenes Under Henry Reaction Conditions

Abstract

A series of β‐carbonyl‐substituted 1H‐benzo[f]chromenes has been introduced into the reaction with nitromethane in the presence of ammonium acetate. It has been shown that in the case of 1H‐benzo[f]chromene‐2‐carbaldehydes, the reaction does not stop at the formation of the classical Henry reaction products − β‐nitroalcohols, but their dehydration to nitrovinylchromenes takes place. In the case of alkyl(benzochromen‐2‐yl)ketones, 3‐alkyl‐2‐(2‐nitrovinyl)‐1H‐benzo[f]chromenes are formed, and methoxalyl‐substituted benzochromenes give 10‐amino‐7a,8‐dihydrobenzo[5,6]chromeno[2,3‐b]pyrrol‐9(11H)‐ones under the Henry reaction conditions.