反应详情

温度

100 °C

Vinyl L-menthoxyacetate is prepared from acetaldehyde, L-menthoxyacetyl chloride, and pyridine catalyst. A 70 mL stainless steel high pressure reactor fitted with a Pyrex glass liner and magnetic stir bar is charged with THF (5 mL), (PPh3)2PdCl2 (0.05 mmol), CH3OH (0.5 mmol), and vinyl L-menthoxyacetate (0.5 mmol). The reactor is sealed, pressurized to 1000 psig with CO, and stirred for 24 hours at 100° C. The product mixture, isolated after removal of gas from the reactor vessel, contains a diastereomeric mixture of methyl L-menthoxyacetyl-L-lactate and methyl L-menthoxyacetyl-D-lactate. The diastereomers are separated by preparative gas chromatography using an SE-30 liquid phase column. Each diastereomer is hydrolyzed separately by treatment with 2N HCl (aq) for 2 hours at 100° C. to give pure L- and D-lactic acid, methanol, and L-menthoxyacetic acid. The L-menthoxyacetic acid is recycled to L-menthoxyacetyl chloride by treatment with thionyl chloride.

1. customA 70 mL stainless steel high pressure reactor fitted with a Pyrex glass liner and magnetic stir bar
2. customThe reactor is sealed
3. customThe product mixture, isolated
4. customafter removal of gas from the reactor vessel
5. additiona diastereomeric mixture of methyl L-menthoxyacetyl-L-lactate and methyl L-menthoxyacetyl-D-lactate
6. customThe diastereomers are separated by preparative gas chromatography
7. waitEach diastereomer is hydrolyzed separately by treatment with 2N HCl (aq) for 2 hours at 100° C.