반응 #505531

반응 방정식

((S)-2-Amino-4,5,6,7-tetrahydro-benzothiazol-6-yl)-carbamic acid tert-butyl ester

DIPEA

chloroformate

DIPEA

benzyl chloroformate

→

((S)-6-tert-butoxycarbonylamino-4,5,6,7-tetrahydro-benzothiazol-2-yl)-carbamic acid benzyl ester

수율 91.1%

용매

CH2Cl2

반응 조건

후처리

1. 1
   workup.STIRRINGStirred for 4 h
2. 2
   기타Quenched with 200 mL of saturated NH4Cl
3. 3
   세척Washed with 2×200 mL of H2O, 200 mL of Na2CO3 and 1×200 mL of brine
4. 4
   여과Dried organic phase with MgSO4, filtered
5. 5
   농축concentrated
6. 6
   기타Applied to a SiO2 column and purified (5:5 CH2Cl2/hexanes to 9:1 CH2Cl2/MeOH)
7. 7
   기타to give two main fractions

실험 절차

Dissolved ((S)-2-Amino-4,5,6,7-tetrahydro-benzothiazol-6-yl)-carbamic acid tert-butyl ester (32.6 g, 121.02 mmol) in 300 mL of CH2Cl2. To this was added DIPEA (41.8 mL, 240 mmol). The mixture was cooled to 4° C. To this was added the benzyl chloroformate (17.8 mL, 125 mmol). The mixture stirred overnight. TLC analysis indicated some starting material remaining. Added 0.3 eq more of chloroformate and 0.3 eq. more of DIPEA. Stirred for 4 h. TLC indicated remaining starting material Quenched with 200 mL of saturated NH4Cl. Washed with 2×200 mL of H2O, 200 mL of Na2CO3 and 1×200 mL of brine. Dried organic phase with MgSO4, filtered and concentrated. Applied to a SiO2 column and purified (5:5 CH2Cl2/hexanes to 9:1 CH2Cl2/MeOH) to give two main fractions. 1H NMR analysis indicated that both fractions were acceptable and they were combined to give 44.5 g of ((S)-6-tert-butoxycarbonylamino-4,5,6,7-tetrahydro-benzothiazol-2-yl)-carbamic acid benzyl ester. 3.06 g of S.M recovered 9%.

출처