Pyrimidine → 5-(Benzyloxy)-1,2-dimethyl-6-oxo-1,6-dihydropyrimidine-4-carboxylic acid

Participants

Reaction Conditions

Reaction Steps

The above pyrimidine, 32 (9.00 g, 34.6 mmol), TEMPO catalyst (55 mg), Adogen-464 phase transfer catalyst (690 mg) and NaBr (360 mg, 3.50 mmol) were combined in CH2Cl2 (400 mL) and water (10 mL). After cooling to 0° C. the reaction was stirred at 1500 r.p.m. while adding a cooled (10° C.) buffered bleach solution (125 mL commercial bleach+125 mL water +12.5 g NaHCO3) keeping the reaction <4° C. (takes approx. 15 min). After a further 5 min, 2M NaOH solution was added until a solution of pH 10 was obtained. The CH2Cl2 layer was separated and extracted with basic water (pH 10, 100 mL). The combined aqueous solutions were washed with CH2Cl2 (50 mL). The aqueous phase was concentrated to ˜200-250 mL and carefully acidified (conc. HCl) to pH 2, concomitant with precipitation. After standing at 5° C. overnight the white solid was filtered, washed with water and dried under high vacuum to give 5.20 g (54.9%) of 33. Mp: 180-181° C. (+)FABMS: m/z 275. 1H NMR (CDCl3, 300 MHz): δ 2.53 (s, 3H, 2-Me), 3.55 (s, 3H, N-Me), 5.46 (s, 2H, BnCH2), 7.30-7.38 (m, 3H, Ph), 7.49-7.52 (m, 2H, Ph). 13C NMR (DMSO-d6, 100 MHz): δ 22.6, 31.2 73.3, 128.0, 128.2, 128.3, 136.9, 139.1, 143.0, 155.7, 159.2, 165.7. Anal. Calcd (found) for C14H14N2O4: C, 61.31(61.36); H, 5.14 (5.06); N, 10.21(10.30).

Provenance & Evidence