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ChemicalBook CAS DataBase List 3,4-DIHYDRO-2H-1,5-BENZODIOXEPINE-6-CARBOXYLIC ACID

3,4-DIHYDRO-2H-1,5-BENZODIOXEPINE-6-CARBOXYLIC ACID synthesis

3synthesis methods
-

Yield:66410-67-1 91%

Reaction Conditions:

Stage #1: methyl 3,4-dihydro-2H-benzo[b][1,4]dioxepine-6-carboxylatewith methanol;sodium hydroxide;water in tetrahydrofuran at 20;
Stage #2: with hydrogenchloride in water;

Steps:

113.3

To a solution of methyl 3,4-dihydro-2H-1,5-benzodioxepine-6-carboxylate (1.615 g, 7.757 mmol) in methanol (20 ml) - tetrahydrofuran (10 ml) was added 1N aqueous sodium hydroxide solution (15.5 ml, 15.5 mmol) and the mixture was stirred overnight at room temperature. The reaction solution was concentrated, diluted with water, acidified with dilute hydrochloric acid and extracted twice with ethyl acetate. The collected organic layer was dried over anhydrous sodium sulfate and the solvent was evaporated under reduced pressure. The residue was crystallized from-hexane to give the objective substance. white crystal yield 1.376 g, 91% mp 68-70°C; 1H-NMR (CDCl3, 200MHz) δ 2.29-2.40 (2H, m), 4.30 (2H, t, J = 5.8 Hz), 4.52 (2H, t, J = 5.6 Hz), 7.09 (1H, t, J = 7.9 Hz), 7.24 (1H, dd, J = 2.0 Hz, 8.2 Hz), 7.85 (1H, dd, J = 1.8 Hz, 7.6 Hz); IR (KBr) 3171, 1725, 1478, 1348, 1264, 1022, 752 cm-1; Anal. Calcd for C10H10O4: C, 61.85; H, 5.19. Found: C, 61.77; H, 5.49.

References:

EP1362846,2003,A1 Location in patent:Page/Page column 86