تفاعل #93881

معادلة التفاعل

hydrochloric acid

L-leucine

sodium carbonate

9-fluorenylmethylchloroformate

→

N-9-fluorenylmethoxycarbonyl-L-leucine

المذيبات

water

tetrahydrofuran

ظروف التفاعل

المعالجة

1. 1
   workup.ADDITIONis added a solution of 19.1 g
2. 2
   تركيزconcentrated
3. 3
   أخرىto remove the solvent
4. 4
   استخلاصThe residue is extracted with ethyl acetate
5. 5
   غسيلthe extract is washed with 100 ml
6. 6
   تجفيفof water, dried
7. 7
   أخرىevaporated to dryness

الإجراء التجريبي

To a mixture consisting of 19.4 g. of L-leucine, 15.7 g. of sodium carbonate, and 500 ml. of water, cooled to 0° C., is added a solution of 19.1 g. of 9-fluorenylmethylchloroformate in 200 ml. of tetrahydrofuran, and the resulting mixture is stirred at 0° C. for one hour and at room temperature for 15 hours. The mixtue is then acidified with 3 N hydrochloric acid and concentrated to remove the solvent. The residue is extracted with ethyl acetate, and the extract is washed with 100 ml. of 10% hydrochloric acid and with 100 ml. of water, dried, and evaporated to dryness to give a residue of N-9-fluorenylmethoxycarbonyl-L-leucine, which is slurried with n-hexane, isolated, and dried; m.p. 76°-79° C.; [α]D25 -28.7° (1.01% in methanol). To a mixture consisting of 15.2 g. of this intermediate product, 37 g. of pentachlorophenol, and 300 ml. of N,N-dimethylformamide, cooled to 5° C., is added 9.8 g. of dicyclohexylcarbodiimide, and the resulting mixture is kept at 4° C. for 2 days. It is then filtered, and the filtrate is evaporated to dryness to give a residue of N-9-fluoroenylmethoxycarbonyl-L-leucine pentachlorophenyl ester, which is triturated with n-hexane, isolated and dried; m.p. 119°-121° C.; [α]D25 -35.4° (1.00% in methanol).

المصدر