Heterocyclic sulfones. Part IV. A novel synthesis of pyrrole and fused heterocyclic sulfones

Abstract

The applicability and synthetic potency of the novel reagents diethyl 2-aryl-3-(phenylsulfonyl)propene-1,1-dicarboxylate 3 are reported. Compounds 3 are shown to be key precursors in heterocyclic sulfones syntheses. Chemical and spectroscopic evidence for the structure of the newly synthesized compounds are described.

Heterocyclic synthesis with activated nitriles : An expeditious synthetic approach to polyfunctionally substituted pyrroles, heterocyclopyrimidines and coumarins

“…Its IR spectrum showed absorption peaks at ν 3340 (NH), and 2220, 2216, 2208 cm -1 (3CN). Its 1 H-NMR spectrum (DMSO-d 6 ) showed a singlet signal (2H) at δ 4.12 ppm assigned for the CH 2 protons, a singlet at δ 7.32 ppm assigned for the CH proton and a broad singal at δ  9.11 ppm assigned for the NH proton which underwent a facile hydrogen deuterium exchange and disappeared upon addition of D 2 O to the NMR sample. The structure of 3 was further confirmed on the basis of its chemical behaviour towards different chemical reagents.…”

“…Compound 4 underwent an intramolecular heterocyclization, upon boiling under reflux in dry pyridine, to afford 3-amino-2,4-dicyano-1-methylpyrrole (6). Compound 3 readily reacted with an equimolar amount of ethyl chloroacetate in aqueous Na 2 CO 3 solution, under reflux, to yield ethyl 3-amino-4-cyano-1-cyanomethylpyrrole-2-carboxylate (7) (Scheme 1).…”