1,3-Dipolar Addition of 2-Benzonitrilo-2-propanid to 7-Methylthienopyridine 1,1-Dioxide and Subsequent Reactions

Article abstract of DOI:10.1002/hlca.19830660330

The addition of dipole 2, generated photochemically from 2,2-dimethyl-3-phenyl-2H-azirine (1), to 7-methylthieno<2,3-c>pyridine 1,1-dioxide yields the pyrroline derivative 4 as a major product and regioisomer 5 in low yield.Compound 4 can be transformed into the pyrrolidine derivative 11 by ring opening, loss of SO2 and hyrogenation.Bromopyrroline derivative 14 gives either by dehydrohalogenation compound 18 or, by substitution, nitrile 17 or ethoxy derivative 19.Substitution of 14 and ring opening yields methoxypyrrole derivative 20, which gives acces to the unstable hydroxypyrrole and hydroxypyrrolidine derivative 28 resp. 30.The vinylsulfone 18 is the starting material for addition-ring-cleavage reactions.Oxidation of pyrroline derivative 4 gives epoxy-substituted N-oxide 39 and di-N-oxide 40; and oxidative transformation of pyrrolidine derivative 11 yields the (hydroxymethyl)pyridylpyrrolidine derivative 45.