反应详情

Sodium chlorite (8.08 g) was added over a period of 30 seconds to a stirred solution 2-hydroxy-5-(2-methoxyethoxy)benzaldehyde (see Example 41) and sodium methoxide in methanol (25% by weight solution, 9.68 ml) in dimethylsulphoxide (350 ml) at 15° C. After warming to room temperature and stirring for 3 hours the mixture was added to water (600 mls), acidified with 2M aqueous hydrochloric acid, and extracted with diethyl ether (4×250 mls). The ethereal extracts were combined, washed with water (2×100 ml), dried (MgSO4) and evaporated. The residue was crystallised from toluene to give 2-hydroxy-5-(2-methoxyethoxy)benzoic acid (4.1 g) as solid m.p. 115-116° C.; NMR 3.3(3H,s), 3.65(2H,m), 4.05(2H,m), 6.9(1H,d), 7.15(1H, d of d), 7.25(1H,d); m/z 213(M+H).

1. extractionextracted with diethyl ether (4×250 mls)
2. washwashed with water (2×100 ml)
3. dry with materialdried (MgSO4)
4. customevaporated
5. customThe residue was crystallised from toluene