Benzaldehyde dimethyl acetal → 3-(5-Chloro-2-methoxy-benzenesulfonyl)-2-phenyl-2,3-dihydro-benzooxazole-5-carboxylic acid methyl ester

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Reaction Conditions

Reaction Steps

A mixture of 3-(5-chloro-2-methoxy-benzenesulfonylamino)-4-hydroxy-benzoic acid methyl ester (example 30, step 1; 200 mg, 0.537 mmol), benzaldehyde dimethyl acetal (0.5 mL) and toluene-4 sulfonic acid monohydrate (10 mg, 54 μmol) was stirred at 100° C. for 48 h. After cooling, heptane was added, and the precipitate was collected by filtration to afford 3-(5-chloro-2-methoxy-benzenesulfonyl)-2-phenyl-2,3-dihydro-benzooxazole-5-carboxylic acid methyl ester (208 mg, 84%). Light yellow solid, MS (ISP)=460.2 (M+H)+.

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