反应详情

To a solution of 4-bromo-3-methylisothiazol-5-amine (prepared as described in J. Chem. Soc. 1963, p 2032) (1.93 g, 10.1 mmol) in tetrahydrofuran (25 mL) with triethylamine (1.7 mL, 12.2 mmol) at 0° C. was added slowly a solution of Example 4A (1.9 g, 10.3 mmol) in tetrahydrofuran (15 mL). The reaction was allowed to warm to room temperature and stirred overnight. The reaction was evaporated to dryness, partitioned between H2O/ethyl acetate and the aqueous extracted again (2×) with ethyl acetate. The organics were combined, dried (MgSO4), filtered and solvent evaporated. Flash chromatography over silica gel eluting with 15% ethyl acetate/hexane provided 0.3 g of the title compound plus 1.8 g of diacylated compound. The latter was heated to reflux in methanol for 3 h, cooled, solvent evaporated and flash chromatographed over silica gel eluting with 20% ethyl acetate/hexane to provide an additional 0.99 g of the title compound. 1H NMR (300 MHz, CDCl3) δ ppm 1.63-1.76 (m, 4H), 1.87-1.98 (m, 4H), 2.10-2.15 (m, 2H), 2.45 (s, 3H), 2.81 (t, 1H), 8.23 (br s, 1H).

1. customThe reaction was evaporated to dryness
2. custompartitioned between H2O/ethyl acetate
3. extractionthe aqueous extracted again (2×) with ethyl acetate
4. dry with materialdried (MgSO4)
5. filtrationfiltered
6. customsolvent evaporated