1,2:3,4-Di-O-isopropylidene-alpha-D-galactopyranose → 3-[1-(3,5-dimethyl-1H-pyrrol-2-yl)-meth-(Z)-ylidene]-2-oxo-2,3-dihydro-indole-1-carboxylic acid (3aR, 5aS, 8aS, 8bR)-2,2,7,7-tetramethyl-tetrahydro-bis[1,3]dioxolo[4,5-b;4',5'-d]pyran-5-ylmethyl ester

Participants

Reaction Steps

To a solution of 1,2,3,4-di-O-isopropylidene-D-galactopyranose (650 mg, 2.5 mmol) in 1.0 mL of pyridine and 2.0 mL of THF was added a suspension of 3-[1-(3,5-dimethyl-1H-pyrrol-2-yl)-meth-(Z)-ylidene]-2-oxo-2,3-dihydro-indole-1-carbonyl chloride (150 mg, 0.5 mmol) at 0° C. The reaction mixture was then gradually warmed to room temperature, stirred for 4 h, and concentrated. The residue was triturated with water and washed with ether to give 170 mg (65%) of 3-[1-(3,5-dimethyl-1H-pyrrol-2-yl)-meth-(Z)-ylidene]-2-oxo-2,3-dihydro-indole-1-carboxylic acid (3aR,5aS,8aS,8bR)-2,2,7,7-tetramethyl-tetrahydro-bis[1,3]dioxolo[4,5-b;4′,5′-d]pyran-5-ylmethyl ester.

Provenance & Evidence