Реакция #1416

Уравнение реакции

methyl iodide

Cesium carbonate

N2 [(1,1-dimethylethoxy)carbonyl]-N6 -[(phenylmethoxy)carbonyl]-L-lysine

water methanol

→

N2 [(1,1-Dimethylethoxy)carbonyl]-N6 -[(phenylmethoxy)carbonyl]-L-lysine, methyl ester

Растворители

—

hexanes

ethyl acetate

ethyl acetate

Условия реакции

Обработка

1. 1
   Другоеthe residual water removed azeotropically with acetonitrile (3×)
2. 2
   ДругоеThe resulting oil was dried in vacuo
3. 3
   workup.DISSOLUTIONdissolved in dry dimethyl-formamide
4. 4
   Промывкаwashed successively with water (2×25 ml.), saturated sodium bicarbonate (25 ml.) and brine (25 ml.)
5. 5
   СушкаThe organic phase was dried (anhydrous magnesium sulfate)
6. 6
   Фильтрацияfiltered
7. 7
   Другоеevaporated to dryness
8. 8
   Другоеdried in vacuo
9. 9
   Другоеto give 10.11 g

Методика

Cesium carbonate (4.28 g., 13.1 moles) was added to a mixture of N2 -[(1,1-dimethylethoxy)carbonyl]-N6 -[(phenylmethoxy)carbonyl]-L-lysine (10 g., 26.3 moles) and 20% water-methanol (60 ml.). The solution became homogeneous within 5 minutes so the solvent was stripped and the residual water removed azeotropically with acetonitrile (3×). The resulting oil was dried in vacuo, dissolved in dry dimethyl-formamide and treated with methyl iodide (3.2 ml., 2.0 eq.). The reaction mixture was stirred at room temperature for 1.5 hours under argon, diluted with ethyl acetate (200 ml.) and washed successively with water (2×25 ml.), saturated sodium bicarbonate (25 ml.) and brine (25 ml.). The organic phase was dried (anhydrous magnesium sulfate), filtered, evaporated to dryness and dried in vacuo to give 10.11 g., of product as a light yellow syrup; Rf =0.30 (ethyl acetate:hexanes, 1:2).

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