tert-butyl (4-{3-chloro-2-[(2,5-dioxo-1-pyrrolidinyl)methyl]-7-oxido-5,8-dihydro-6H-thiopyrano[4',3':4,5]thieno(2,3-b]pyridin-4-yl}phenoxy)-acetate → (4-{3-chloro-2-[(2,5-dioxo-1-pyrrolidinyl)methyl]-7-oxido-5,8-dihydro-6H-thiopyrano[4',3':4,5]thieno[2,3-b]pyridin-4-yl}phenoxy)acetic acid

Participants

Reaction Steps

A solution of the compound obtained in Example 113 (600 mg) in formic acid (7 ml) was stirred at room temperature for 6 hours and then concentrated under reduced pressure. The residue was diluted with methylene chloride and washed with water and dried (MgSO4) and the solvent was distilled off under reduced pressure. The residue was subjected to silica gel column chromatography to obtain (4-{3-chloro-2-[(2,5-dioxo-1-pyrrolidinyl)methyl]-7-oxido-5,8-dihydro-6H-thiopyrano[4′,3′:4,5]thieno[2,3-b]pyridin-4-yl}phenoxy)acetic acid from the fraction eluted with chloroform-ethyl acetate (7:1) and then chloroform-methanol (10:1) (476 mg, 88%). It was recrystallized from methanol-hexane. Colorless prisms. Melting point 205-206° C.

Provenance & Evidence