Process for preparing optically active epoxides
AssigneePhoenix Chemicals Limited
InventorDavid Edward Justice
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Abstract
The invention concerns a process for the production of optically active epoxides useful as pharmaceutical intermediates, particularly in the field of HIV protease inhibitors. The optically active epoxides are produced in commercially acceptable yields from an optically active alcohols by a Mitsunobu reaction and a cyclisation step, preferably comprising an intermediate recrystallisation step. The stereochemistry of the alcohol is inverted during the Mitsunobu reaction to produce the desired epoxide.
Claims13
A process for producing an optically active (2R, 3S)-epoxide of the general formula (1):
- 9
- or its enantiomer wherein each of R1 and R2 is independently selected from hydrogen, optionally substituted alkyl, aryl, aralkyl or alkaryl groups, and amine-protecting groups and R3 is selected from hydrogen and optionally suitably protected alkyl, cycloalkyl, aryl, aralkyl or alkaryl groups which comprises conducting a Mitsunobu reaction on an optically active (2S,3S)-alcohol of general formula (2):
- 10
- or its enantiomer wherein X is a leaving group and R1, R2 and R3 are the same as the corresponding R1, R2 and R3 in formula (1) and cyclising the resulting Mitsunobu product, the stereochemistry of the optically active (2S,3S)-alcohol or its enantiomer being inverted in the Mitsunobu reaction step.
A process according to any one of claims 1 to 12, wherein the amine protecting group is butoxy/carbonyl.
Dependencies are inferred from the claim text.