Hydrochloric Acid → 4-Hydroxy-7-iodo-1-oxo-1,2-dihydro-isoquinoline-3-carboxylic acid butyl ester

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Reaction Conditions

Reaction Steps

Freshly cut sodium metal, 0.40 g, was dissolved in 22 ml of n-butanol at 65° C. under a nitrogen atmosphere. A mixture of 3.0 g of (5-iodo-1,3-dioxo-1,3-dihydro-isoindol-2-yl)-acetic acid methyl ester in 22 ml of n-butanol was added to the sodium butoxide solution and the reaction mixture was heated to 80° C. for 2 h. The cooled reaction mixture was acidified with 100 ml of 1 M hydrochloric acid to give a solid precipitate. The solid was collected by filtration and separated by silica gel chromatography (eluant; 19:1 dichloromethane:ethyl acetate) to give 0.219 g of 4-hydroxy-7-iodo-1-oxo-1,2-dihydro-isoquinoline-3-carboxylic acid butyl ester: MS-(−)-ion, M−1=386.0 amu, and 0.150 g of 4-hydroxy-6-iodo-1-oxo-1,2-dihydro-isoquinoline-3-carboxylic acid butyl ester: MS-(−) ion, M−1=386.0 amu.

Provenance & Evidence