反应详情

(EX-1A) A solution of ethyl benzimidate hydrochloride (92.25 g, 496.9 mmol) in 300.0 mL dry methanol (1.68 M) was cooled to ca 0° C. and added a solution of aminoacetaldehyde dimethyl acetal (73.10 mL, 670.9 mmol) in dry methanol (75.0 mL, 9.0 M) drop wise at such a rate the temperature was kept below 5° C. The resulting solution was allowed to stir for 3 days with the temperature being maintained below 5° C. The reaction mixture was then concentrated under reduced pressure to give a yellow oil. The residue was dissolved in 1 N NaOH (750 mL) and extracted with dichloromethane (4×250 mL). The organic solutions were combined, dried (MgSO4), and concentrated to give 108.13 g crude N-(2,2-dimethoxyethyl)benzamidine as a yellow oil. The crude N-(2,2-dimethoxyethyl)benzamidine (108.13 g, 519.2 mmol) in dry methanol (125.0 mL, 4.2 M) was added dimethyl methoxymethylenemalonate (94.13 g, 540.5 mmol) in one portion at room temperature. The resulting mixture was heated to approximately 100° C., where the solvent was slowly distilled off over a two hour period. The resulting dark brown solution was allowed to cool to room temperature and was diluted ethyl acetate (1 L). The organic solution was washed with saturated NH4Cl (2×500 mL) and brine 1×500 ml). The organic solution was dried (MgSO4), filtered and concentrated. Purification of the crude product by MPLC (25% ethyl acetate/hexane) gave pure methyl 1-(2,2-dimethoxyethyl-2-phenylpyrimidin-6(1H)-one-5-carboxylate (EX-1A) in 73% yield as a tan oil: 1H NMR (300 MHz, CDCl3) δ 8.73 (s, 1H), 7.59-7.49 (m, 5H), 4.86 (t, J=5.5 Hz, 1H), 4.16 (d, J=5.4 Hz, 2H), 3.95 (s, 3H), 3.32 (s, 6H); 13CNMR (75 Hz, CDCl3) δ 165.9, 164.6, 159.3, 158.2, 134.6, 130.9, 128.93, 128.78, 114.9, 101.4, 56.0, 55.1, 52.7, 49.1; HRMS (ES) calcd for C16H19N2O5 319.1294, found 319.1288.

1. customwas kept below 5° C
2. temperaturebeing maintained below 5° C
3. concentrationThe reaction mixture was then concentrated under reduced pressure
4. customto give a yellow oil
5. extractionextracted with dichloromethane (4×250 mL)
6. dry with materialdried (MgSO4)
7. concentrationconcentrated