反应详情

Scheme V depicts a method of preparing aldehyde 13. For example, an aldehyde of formula 11 wherein R3, R4 and R5 are hydrogen, i.e., 2,3-dihydroxybenzaldehyde (0.6 g, 4.3 mmol) was added to dimethyl sulfonamide (DMSO) (10 ml) containing sodium hydride (0.25 g, 10.4 mmol). After one hour a solution of benzyl bromide (0.52 ml, 4.3 mmol) in DMSO (5 ml) is added. Stirring the mixture is continued for 24 h, after which time the mixture is poured into water and extracted with chloroform (2×). The aqueous solution then was acidified with 6N hydrochloric acid to adjust the pH from 2 to about 4 and extracted with chloroform (3×). The latter organic layers were washed with 1N hydrochloric acid and filtered over silica gel to give 3-benzyloxy-2-hydroxy benzaldehyde.

1. extractionextracted with chloroform (2×)
2. extractionextracted with chloroform (3×)
3. washThe latter organic layers were washed with 1N hydrochloric acid
4. filtrationfiltered over silica gel