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US 4,539,148 AGranted
Production of 1-oxacephams and intermediates
AssigneeShionogi & Co., Ltd.
InventorsSadao Yamamoto, Hikaru Itani, Hiromi Takahashi, Teruji Tsuji, Wataru Nagata
Life of this patent
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Abstract
Useful intermediates, 7.alpha.-acylamino-3-(oxo or exomethylene)-1-dethia-1-oxacepham-4.alpha.-carboxylates, are produced by the intramolecular carbenoid insertion of a 2-diazo-3-(oxo or exomethylene)-4-(3.alpha.-acylamino-2-oxoazetidin-4.beta.-yl)oxybutyrate prepared in several steps from the corresponding oxazolinoazetidinone and diketone.
Claims3
A 4-oxygenated butyric acid derivative of the formula ##STR96## wherein R is carboxy protecting group;
- R.sup.2 is (1) methylene, (2) hydroxyiminomethylene, (3) hydroxyiminomethylene protected by tri-C.sub.1 to C.sub.5 -alkylsilyl, 1-C.sub.1 to C.sub.5 -alkoxy-C.sub.1 to C.sub.5 -alkyl, tetrahydrofuranyl or tetrahydropyranyl, or (4) diazomethylene;
- X is methylene;
- and
- Y.sup.1 is a group of the formula ##STR97## in which R.sup.1 is (1) C.sub.1 to C.sub.10 -alkyl which is unsubstituted or substituted by phenoxy (2) benzyl, (3) phenyl, (4) methylphenyl, (5) dimethylphenyl, (6) cyanophenyl, (7) nitrophenyl, (8) methoxyphenyl or (9) chlorophenyl and Z is hydrogen or a N-protecting group from the group of C.sub.1 to C.sub.5 -alkanoyl and tri-C.sub.1 to C.sub.5 -alkylsilyl.
1 more element
Dependencies are inferred from the claim text.