The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Nov. 24, 1992
Filed:
Apr. 04, 1990
Stephen Challenger, Walmer, GB;
Pfizer Inc., New York, NY (US);
Abstract
The invention provides a process for preparing a compound of the formula: ##STR1## or a base salt thereof, wherein R.sup.2 is hydrogen or C.sub.1 -C.sub.6 alkyl optionally substituted by up to 3 substituents each independently selected from the group consisting of C.sub.1 -C.sub.6 alkoxy and C.sub.1 -C.sub.6 alkoxy(C.sub.1 -C.sub.6 alkoxy)-; and R.sup.3 is C.sub.1 -C.sub.6 alkyl or benzyl, said benzyl group being optionally ring-substituted by up to 2 nitro or C.sub.1 -C.sub.4 alkoxy substituents comprising reacting a compound of the formula: ##STR2## wherein R.sup.1 is C.sub.1 -C.sub.4 alkyl, phenyl or benzyl or C.sub.1 -C.sub.4 alkoxy; and R.sup.2 and R.sup.3 are as previously defined for a compound of the formula (I), with hydrogen peroxide or a source of peroxide ions: said process being optionally followed by conversion of the compound of the formula (I) to a base salt thereof. The present invention also relates to novel compounds of the formula (II).