Reaktion #1738945

Reaktionsgleichung

2-pyrroline

L-menthoxyacetyl chloride

methanol

pyridine

→

L-proline

D-proline

Lösungsmittel

THF

Reaktionsbedingungen

Aufarbeitung

1. 1
   SonstigeA 70 mL stainless steel high pressure reactor fitted with a Pyrex glass liner and magnetic stir bar
2. 2
   Sonstigeis sealed
3. 3
   SonstigeThe product mixture, isolated
4. 4
   Sonstigeafter removal of gas from the reactor vessel
5. 5
   workup.ADDITIONa mixture of N-(L-menthoxyacetyl)-D-proline methyl ester and N-(L-menthoxyacetyl)-L-proline methyl ester
6. 6
   SonstigeSeparation of these products
7. 7
   workup.ADDITIONthe diastereomers are treated separately with 2N HCl solution at 100° C. for 3 hours

Vorschrift

N-(L-menthoxyacetyl)-2-pyrroline is prepared by condensation of 0.1 mol of 2-pyrroline with 0.1 mol of L-menthoxyacetyl chloride. A 70 mL stainless steel high pressure reactor fitted with a Pyrex glass liner and magnetic stir bar is charged with THF (5 mL), methanol (0.5 mmol), Co2 (CO)8 (0.05 mmol), pyridine (0.25 mmol), and N-(L-menthoxyacetyl)-2-pyrroline (0.5 mmol.) The reactor is sealed, pressurized to 1000 psig with CO, and the reaction mixture is stirred for 24 hours at 100° C. The product mixture, isolated after removal of gas from the reactor vessel, contains a mixture of N-(L-menthoxyacetyl)-D-proline methyl ester and N-(L-menthoxyacetyl)-L-proline methyl ester. Separation of these products is effected by silica gel chromatography with ether-toluene eluent, and the diastereomers are treated separately with 2N HCl solution at 100° C. for 3 hours to give pure L-proline and D-proline.

Quelle