[CH3:1][O:2][CH2:3][N:4]1[CH:8]=[CH:7][N:6]=[C:5]1[S:9][C:10]1[CH:15]=[CH:14][CH:13]=[CH:12][CH:11]=1.[Li]CCCC.[C:21](OC)(=[O:26])[C:22]([O:24][CH3:25])=[O:23].[NH4+].[Cl-]>C1COCC1.CCOCC>[CH3:1][O:2][CH2:3][N:4]1[C:8]([C:21](=[O:26])[C:22]([O:24][CH3:25])=[O:23])=[CH:7][N:6]=[C:5]1[S:9][C:10]1[CH:15]=[CH:14][CH:13]=[CH:12][CH:11]=1
To a cold (−78° C.), stirred solution of 1-methoxymethyl-2phenylthioimidazole (Ohta, S. et al. (1992) Chem. Pharm. Bull. 40:2681) (11) 340 mg, 1.55 mmol) in dry THF (8.0 mL) was added a solution of n-BuLi (1.47 M in hexanes, 1.26 mL, 1.85 mmol) and the mixture was stirred for 1 hour. A solution of dimethyl oxalate (540 mg. 4.58 mmol) in dry THF (2.0 mL) was added and the mixture was stirred at −78° C. for an additional 1.25 hours. The reaction mixture was treated with saturated aqueous NH4Cl (5.0 mL) and Et2O (20 mL). The phases were separated and the aqueous layer was extracted with Et2O (25 mL). The combined organic extracts were washed (brine, 10 mL), dried (MgSO4), and concentrated. Flash chromatography (35 g of silica gel, 1:1 petroleum ether-Et2O) of the crude material afforded 305 mg (66%) of 8 as a beige solid that exhibited mp 59-60° C.; IR (KBr) 1729, 1657, 1305, 1273, 1167, 1114, 784 cm−1; 1H NMR (CDCl3, 400 MHz) δ8.23 (s, 1H), 7.52-7.54 (m. 2H), 7.37-7.38 (m, 3H), 5.81 (s, 2H), 3.91 (s, 3H), 3.36 (s, 3H); 13C NMR (CDCl3, 100 MHz) δ172.2, 161.6, 154.1, 145.4, 145.3, 133.2, 129.5, 129.2, 128.7, 75.8, 56.5, 53.0; HREIMS calcd for C14H14N2O4`S 306.0674, found 306.0674.
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