反应详情

The title compound was prepared from 1,3-bis(cyclohexylmethyl)-5,6-diaminouracil by the method of J. Perutmattam, Syn. Commun. 1989, 19:3367-3370. 1,3-Bis(cyclohexylmethyl)-5,6-diaminouracil was freshly prepared by shaking a mixture of 6-amino 1,3-bis(cyclohexylmethyl)-5-nitrosouracil (from step (c), 5.00 g) in methanol (250 ml)-water (25 ml) with 10% palladium on carbon (0.50 g) under hydrogen at 344.7 kPa (50 psi) on a Parr shaker for 2 h. The catalyst was filtered off (Celite ™) and the colorless filtrate was concentrated to 25 ml. 4-Formylcinnamic acid (Aldrich, 2.53 g, 14.35 mmol) was added to this solution of 1,3-bis(cyclohexylmethyl)-5,6-diaminouracil and the resulting yellow mixture was concentrated and the residual yellow solid dried by evaporation of several portions of absolute ethanol. The resulting yellow powder (Schiff base intermediate) was stirred in dimethoxyethane (115 ml) with iodine (4.0 g) at 60° C. (oil bath) for 20 h. A saturated aqueous solution of sodium thiosulfate was added to the warm reaction mixture until complete decolorization of iodine resulted. The pale yellow precipitate was filtered off, washed with water, and dried at 67 Pa (0.5 Torr) to give (E)-4-[1,3 bis(cyclohexylmethyl)-1,2,3,6-tetrahydro-2,6-dioxo-9H-purin-8-yl]cinnamic acid as a pale yellow powder (6.73 g, 91%), m.p.>300° C. Such samples were further purified by dissolving them in 1N aqueous sodium hydroxide, filtering the resulting hazy solution through Celite™, and acidifying the clear filtrate with hydrochloric acid. The resulting precipitate was filtered and washed with water to give title compound as a pale yellow powder, m.p. >300° C.; 1H-NMR (DMSO-d6) δ: 13.80 and 12.40 (both br m, 1 each, CO2H and NH), 8.12 (d, J=8.3 Hz, 2, 2 phenyl CH), 7.84 (d, J=8.4 Hz, 2, 2 phenyl CH), 7.64 (d, J=16.0 Hz, 1, CH═), 6.64 (d, J=16.0 Hz, 1, CH═), 3.93 (d, J=7.0 Hz, 2, CH2N), 3.79 (d, J=6.8 Hz, 2, CH2N), 2.0-1.4 and 1.3-0.85 (both br m, 22 total, 2 cyclohexyl).

1. filtrationThe catalyst was filtered off (Celite ™)
2. concentrationthe colorless filtrate was concentrated to 25 ml
3. concentrationthe resulting yellow mixture was concentrated
4. dry with materialthe residual yellow solid dried by evaporation of several portions of absolute ethanol
5. stirringThe resulting yellow powder (Schiff base intermediate) was stirred in dimethoxyethane (115 ml) with iodine (4.0 g) at 60° C. (oil bath) for 20 h
6. additionA saturated aqueous solution of sodium thiosulfate was added to the warm reaction mixture until complete decolorization of iodine
7. customresulted
8. filtrationThe pale yellow precipitate was filtered off
9. washwashed with water
10. customdried at 67 Pa (0.5 Torr)