反应详情

A 0.43 M solution of sodium ethoxide (Solution A) was prepared with freshly cut sodium and anhydrous ethanol. An ethanol solution of Compound 1, (S)-2-mercapto-4-methylpentanoic acid (0.72 g in 25 mls), (solution B), was prepared. A 13.5 ml volume of solution A was slowly added to 15 ml of solution B under nitrogen atmosphere. The solution was stirred for five minutes, and the ethanol removed in vacuo, and the white solid repeatedly evaporated with benzene until dry. The resulting disodium salt of mercaptoleucine was dissolved in ~1 ml of dimethylsulfoxide (DMSO) to which was added 1.58 g of compound 2 dissolved in 2 mls of DMSO, and stirred overnight. The reaction mixture was combined with 175 ml of distilled water and extracted with 20 ml portions of ether three times and then acidified with 5N HCl with stirring at 0° C. The aqueous solution was re-extracted 3X with ethyl acetate. The extract was washed with a saturated NaCl solution and dried over sodium sulfate, filtered, and the ethyl acetate removed in vacuo yielding 1.05 g of a clear oil. This was crystallized from ethyl acetate and hexane; yielding a white solid; (0.83 g), (mp, 110-111), ([.varies.]25=52.5 (C0.88 l, MeoH)).

1. customthe ethanol removed in vacuo
2. customthe white solid repeatedly evaporated with benzene
3. customuntil dry
4. dissolutionThe resulting disodium salt of mercaptoleucine was dissolved in ~1 ml of dimethylsulfoxide (DMSO) to which
5. additionwas added 1.58 g of compound 2
6. dissolutiondissolved in 2 mls of DMSO
7. stirringstirred overnight
8. extractionextracted with 20 ml portions of ether three times
9. stirringwith stirring at 0° C
10. extractionThe aqueous solution was re-extracted 3X with ethyl acetate
11. washThe extract was washed with a saturated NaCl solution
12. dry with materialdried over sodium sulfate
13. filtrationfiltered
14. customthe ethyl acetate removed in vacuo