-Cycloaddition of α,β-Unsaturated Hydrazones. Isothiazolopyridin-3(2H)-on-1,1-Dioxides ( = 4-Azasaccharine Derivatives)

Article abstract of DOI:10.1002/hlca.19890720702

The <4 + 2> cycloaddition of α,β-unsaturated hydrazones of type 1 (1-azabuta-1,3-dienes) with isothiazol-3(2H)-on 1,1-dioxide derivatives 10 affords, depending on the solvent used, picolinamides 15 or 17, 4,7-dihydro-4-azasaccharine 14 or 4-azasaccharine