Process for preparing substituted cyclobutanes
AssigneeBristol-Myers Squibb Company
InventorsRichard J. Pariza, Steven M. Hannick, Thomas J. Sowin, Elizabeth M. Doherty
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Abstract
The present invention relates to a process for the preparation of substituted cyclobutanes and their use as intermediates for the preparation of anti-viral nucleoside analogs.
Claims4
A process for the preparation of the substantially pure (-)-enantiomeric form of the compound of the formula:
- ##STR7## wherein Men represents a menthyl comprising reacting the di-(-)-menthyl ester of fumaric acid with 1,1-bis(methylthio)ethylene in the presence of a Lewis acid catalyst.
The compound of the formula ##STR8##
A process for the preparation of the substantially pure (-)-enantiomeric form of the compound of the formula ##STR9## wherein Men represents menthyl and R.sub.a and R.sub.b are loweralkyl comprising reacting the di-(-)-menthyl ester of fumaric acid with a dithioketal of the formula ##STR10## in the presence of a Lewis acid.
A substantially pure (-)-enantiomeric form of the compound of the formula:
- ##STR11## wherein Men represents menthyl and R.sub.a and R.sub.b are loweralkyl.
Dependencies are inferred from the claim text.