[CH2:1]([C:5]1[N:9]([S:10]([N:13]([CH3:15])[CH3:14])(=[O:12])=[O:11])[CH:8]=[CH:7][N:6]=1)[CH2:2][CH2:3][CH3:4].C([Li])CCC.[CH:21](OC)=[O:22]>O1CCCC1.CCCCCC>[CH2:1]([C:5]1[N:9]([S:10]([N:13]([CH3:15])[CH3:14])(=[O:12])=[O:11])[C:8]([CH:21]=[O:22])=[CH:7][N:6]=1)[CH2:2][CH2:3][CH3:4]1.25 g of 2-butyl-3-dimethylaminosulfonylimidazole was dissolved in 25 ml of tetrahydrofuran and cooled to -70° C., and 3.3 ml of n-butyllithium, 1.6 n in hexane, was added. After 1 hour, 0.64 ml of methyl formate was added, and the mixture was heated to room temperature and stirred for 17 hours at this temperature. The mixture was then concentrated, methylene chloride/water was added and the mixture was neutralized by adding 10 percent strength sulfuric acid. The organic phase was dried with Na2SO4 and concentrated by evaporation to give 1.35 g of crude product in the form of a yellow oil, which was purified by chromatography over methylene chloride/methanol/hexane 90:5:5 to give 0.99 g of product. The yield was 76 percent. Other data concerning the roduct was:
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