Synthesis and reactivity of 4-amino-substituted furfurals.

γ-Hydroxy α,β-unsaturated acetylenic ketones have been converted to 4-amino-substituted furfurals by reaction with secondary amines followed by treatment with acid in a mixture of THF and water. The stability of the furfurals depends to some extent on the nature of the amino group, whereas the reactivity has been shown to be reagent-dependent. When treated with phosphorus ylids, the expected alkenes are formed with E configuration in high yields, but when exposed to nitroalkanes under basic conditions (the Henry reaction) abnormal transformations appear to occur, and 2-acylated furans are obtained, albeit in low yield, instead of nitroalkanols.