(S)-(-)-2-ISOCYANATO-3-METHYLBUTYRIC ACID METHYL ESTER synthesis
- Product Name:(S)-(-)-2-ISOCYANATO-3-METHYLBUTYRIC ACID METHYL ESTER
- CAS Number:30293-86-8
- Molecular formula:C7H11NO3
- Molecular Weight:157.17
Yield:-
Reaction Conditions:
with pyridine in dichloromethane;toluene at 5; for 1.5 h;
Steps:
1
A mixture of L-valine methyl ester hydrochloride (10.0 g, 59.9 mmol), DCM (300 mL), and pyridine (19.3 mL, 240 mmol) was cooled in an ice/salt bath and a solution of 20% phosgene in PhMe (35.6 mL, 719 mmol) added dropwise, maintaining the reaction temperature below 5°C during the addition. A white suspension resulted and after 1.5 hours, the reaction mixture was poured into ice-cold IM HCl and extracted with DCM (2 x 50OmL). The combined organic phases were washed with brine, dried over anhydrous MgSO4, and evaporated. Flash column chromatography on silica (95 hexanes / 5 EtOAc) gave the title compound as a colorless oil (6.43g). 1H NMR (CDCl3 500MHz) δ 3.94 (d, J= 4.0 Hz, 1 H), 3.82 (s, 3 H), 2.24 (m, 1 H), 1.03 (d, J= 7.0 Hz, 3 H), 0.90 (d, J= 6.5Hz, 3 H) ppm.
References:
WO2008/51475,2008,A2 Location in patent:Page/Page column 33
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