Reaction Steps
In an ice bath, sodium hydride (20 mg, 60%) were added to 6 ml of anhydrous N, N-dimethyl formamide, to which 169 mg of (2S)-methyl 2-(2-chlorophenyl)-2-(2-oxo-7,7a-dihydrothieno[3.2-c]pyridine-5(2H,4H,6H)-yl)-acetate (IV-1) was then added. The reaction was naturally warmed to room temperature, stirred for 1 hr, and then cooled to 0° C. 200 μl of N,N-dimethylcarbamoyl chloride was slowly added dropwise. The reaction was naturally warmed to room temperature, and stirred for 3 hrs, and at this time, TLC showed that the raw materials substantially disappeared. The reaction solution was poured into water (30 ml), the aqueous phase was extracted with ethyl acetate (50 ml×3), and the organic phase was dried to obtain a crude product, which was subjected to flash column chromatography (petroleum ether:ethyl acetate=40:3), to obtain (S)-methyl 2-(2-(N,N-dimethylcarbamoyloxy)-6,7-dihydrothieno[3,2-c]pyridin-5(4H)-yl)-2-(2-chlorophenyl)-acetate (I-18) (95 mg). Yield: 45%, mp 96-98° C., ee=93.5% (chiral HPLC analysis conditions were the same as those in Example 10), [α]D20=+34° (c 0.50, MeOH); 1H-NMR (500 MHz, CDCl3) δ 2.73-2.76 (m, 2H), 2.85-2.89 (m, 2H), 2.99 (s, 3H), 3.03 (s, 3H), 3.52 (d, 1H, J=14.3 Hz), 3.63 (d, 1H, J=14.3 Hz), 3.72 (s, 3H), 4.91 (s, 1H), 6.19 (s, 1H), 7.26-7.69 (m, 4H); 13C-NMR (75 MHz, CDCl3) δ 25.03, 36.37, 36.88, 48.18, 50.40, 52.12, 67.87, 111.48, 125.38, 127.12, 129.09, 129.37, 129.76, 129.95, 130.56, 133.80, 134.34, 134.68, 151.04, 171.27; ESI-MS m/z 409.2 [M+H]+; HRMS Calcd for C19H22N2O4SCl [M+H]+ m/z 409.0992. found 409.0989.
