摘要:
A process for preparing free carboxylic acids which comprises treating an optionally substituted benzyl ester with a Lewis acid, preferably in the presence of a cation acceptor, followed by hydrolysis, if required.
摘要:
Useful intermediates for preparing a 1-dethia-1-oxacephalosporin and represented by the following formula: ##STR1## (wherein R is a monovalent group resulting from the elimination of the carbonyl function of an acyl group derived from a carboxylic or carbonic acid;COB is carboxy or protected carboxy; andX is hydrogen or a nucleophilic group)are prepared from the corresponding penicillin 1-oxides of the following formula: ##STR2## (wherein R, COB, and X are as defined above) by heating, if required in the presence of the desulfurizing reagent, or by exchanging the X group with another one under the condition of an appropriate nucleophilic substitution.
摘要:
Intermediates for preparing an antibacterial 1-dethia-1-oxacephalosporins which are represented by the following formula: ##STR1## wherein R is a monovalent group (minus the carbonyl) from an acyl group derived from a carboxylic or carbonic acid;Y.sup.1 is a divalent group of the following formula: ##STR2## wherein COB is carboxy or protected carboxy;X is hydrogen or a nucleophilic group; andZ is a leaving group are prepared from a compound of the following formula: ##STR3## wherein R and Y.sup.1 are as defined above by the action of an acid. The new compounds of this invention shown by the following formula: ##STR4## wherein A is amino or substituted amino;E is hydrogen or methoxy; andY is a divalent group of the following formula: ##STR5## in which COB, X, and Z are as defined above are convertible into other compounds of the same formula by applying conventional methods in .beta.-lactam chemistry.
摘要:
Compounds represented by the following formula prepared from 6-aminopenicillanic acid are key intermediates in a stereo-specific synthesis of 1-oxadethiacephalosporins, highly active antibiotics: ##STR1## [wherein COA and COB each is carboxy or protected carboxy;Cox is carboxy, protected carboxy, or a group of the formula --COCQ.dbd.N.sub.2 or --COCHQ--Z (in which Q is hydrogen, lower alkyl or aryl; and Z is hydrogen or a nucleophilic group);Hal is halogen;R is lower alkyl or aralkyl; andY is hydrogen or acyl].
摘要:
Intermediates of the following formula are useful for the synthesis of 1-oxacephalosporins. Their preparation from penicillins and the transformation process to make 1-oxacephalosporins are disclosed. The compounds are of the formula: ##STR1## wherein A is amino or a selected acylamino;COB is carboxy or a selected protected-carboxy;X is halogen or the group ORin which R is a group represented by following formulas: ##STR2## wherein Nu is a selected nucleophilic group; R.sup.1 is a group of the following formula: ##STR3## in which Hal is halogen or alkylsulfonyloxy and R.sup.2 is alkyl or aryl; andY is hydrogen or methoxy; with the proviso that when R is propargyl or 2-oxopropyl andR.sup.1 is ##STR4## A is in the 3.alpha.-configuration and Y is 3.beta.-hydrogen or A is in the 3.beta.-configuration and Y is 3.alpha.-methoxy.
摘要:
Intermediates for preparing an antibacterial 1-dethia-1-oxacephalosporins which are represented by the following formula: ##STR1## wherein R is a monovalent group (minus the carbonyl) from an acyl derived from a carboxylic or carbonic acid;Y.sup.1 is a divalent group of the following formula: ##STR2## wherein COB is carboxy or protected carboxy;X is hydrogen or a nucleophilic group; andZ is a leaving groupare prepared from a compound of the following formula; ##STR3## wherein R and Y.sup.1 are as defined above by the action of an acid. The new compounds of this invention shown by the following formula: ##STR4## wherein A is amino or substituted amino;E is hydrogen or methoxy; andY is a divalent group of the following formula: ##STR5## in which COB, X, and Z are as defined above are convertible into other compounds of the same formula by applying conventional methods in .beta.-lactam chemistry.
摘要:
Intermediates for preparing an antibacterial 1-dethia-1-oxacephalosporins which are represented by the following formula: ##STR1## wherein R is a monovalent group (minus the carbonyl) from an acyl derived from a carboxylic or carbonic acid;Y.sup.1 is a divalent group of the following formula: ##STR2## wherein COB is carboxy or protected carboxy;X is hydrogen or a nucleophilic group; andZ is a leaving groupare prepared from a compound of the following formula: ##STR3## wherein R and Y.sup.1 are as defined above by the action of an acid.
摘要:
Intermediates for preparing an antibacterial 1-dethia-1-oxa-cephalosporins which are represented by the following formula: ##STR1## wherein R is a monovalent group (minus the carbonyl) from an acyl derived from a carboxylic or carbonic acid;Y.sup.1 is a divalent group of the following formula: ##STR2## wherein COB is carboxy or protected carboxy;X is hydrogen or a nucleophilic group; andZ is a leaving groupare prepared from a compound of the following formula: ##STR3## wherein R and Y.sup.1 are as defined above by the action of an acid.
摘要:
.alpha.-[3(R)-Substituted amino-4(R)-substituted alkoxy-2-oxo-azetidin-1-yl]-.alpha.-isopropenylacetate (Ia) and .alpha.-[3(R)-substituted amino-4(R)-substituted alkoxy-2-oxo-azetidin-1-yl]-.alpha.-isopropylideneacetate (Ib) prepared from (1R,5S)-.alpha.-(3-substituted-7-oxo-4-oxa-2,6-diazabicyclo[3.2.0]hept-2-en-6-yl)-.alpha.-isopropenylacetate or (1R,5S)-.alpha.-(3-substituted-7-oxo-4-oxa-2,6-diazabicyclo-[3.2.0]hept-2-en-6-yl)-.alpha.-isopropylideneacetate with a primary alcohol in the presence of an acid. The products are useful intermediates for preparing oxadethiacephalosporins.
摘要:
Intermediates represented by the following formulas are useful for synthesizing 3-hydroxy-3-cephem compounds ##STR1## wherein A and B each is a hydrogen or amino substituent; R is a hydrogen or thiol substituent; Hal is a halogen; X is a hydroxy or carboxy protecting group; the broken line between A and R shows that when R and B are hydrogens, and A is a carboxylic acyl, the substituents can be combined to form an azetidinothiazoline bicyclic ring; and the enamine derivatives thereof. One embodiment provides for cyclizing a compound of the formula: ##STR2## wherein A, B, X and Hal are as defined above, which comprises treating the said compound with an acid, base, or solvent if required in the presence of a catalyzer to give a compound represented by following formula ##STR3## In a further embodiment a compound represented by the following formula ##STR4## wherein A, B, R and X are as defined above, is prepared by a process which comprises treating an enamine of a compound represented by following formula ##STR5## wherein A, B, R, X, Hal and broken line are as defined above, with a disubstituted amino containing from 2 to 20 carbon atoms, with the action of an aqueous acid.