Dimethyl 2-methyl-1-(tosylamino)-5-(3-methyl-2-pyrazinyl)pyrrole-3,4-dicarboxylate → Dimethyl 2-methyl-5-(3-methyl-2-pyrazinyl)pyrrole-3,4-dicarboxylate

Participants

Reaction Steps

A solution of 4.57 g of 31C in 20 ml of methanol was added to a mixture of 15 g of Raney nickel in 30 ml of methanol. The mixture was heated at reflux overnight, cooled and the methanol phase was decanted. The catalyst was washed with 100 ml of 1:1 mixture of methylene chloride and methanol. The washings were combined with the methanol phases, and the resulting mixture was stripped of the solvents. The residue was dissolved in a mixture of 20 ml of water and 100 ml methylene chloride. The mixture was acidified to pH=2 with 6N hydrochloric acid, and the solution was neutralized with solid sodium bicarbonate to pH=7. The organic phase was separated, dried (Na2SO4), and stripped of solvent, and the residue was flash chromtographed on silica gel, with a 7:3 v:v mixture of methylene chloride and ethyl acetate as solvent. The product was triturated with ether and the solid product was collected to give 31, as a white solid, m.p.: 155°-156° C.

Provenance & Evidence