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 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:
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 a desulfurizing reagent, or by exchanging the X group with another one under the condition of an appropriate nucleophilic substitution.
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 a desulfurizing reagent, or by exchanging the X group with another one under the condition of an appropriate nucleophilic substitution.
摘要:
Antibacterial 7-substituted aminoacetamido oxadethiacephalosporins of the formula: ##STR1## [wherein R is substituted amino, substituted phenyl, or 5- or 6-membered hetero ring; Ar is aryl; Y is hydrogen or methoxy; Het is 5- or 6-membered aromatic hetero ring; and Z is hydroxy or carboxy protecting group] preparable e.g. by acylation of 7.alpha.-methoxy-7.beta.-amino-3-heterocyclic thiomethyl-3-cephem-4-carboxylic acid derivatives, are highly active against gram-positive and gram-negative bacteria, especially those resistant to other cephalosporins and penicillins.
摘要:
A compound represented by ##STR1## is treated with a base to give an antibacterial cephem compound represented by ##STR2## (wherein A is amino or substituted amino;Cob is carboxy or protected carboxy;Rs is substituted thio;Y is an electron-attracting group selected from acyloxy, halogen, cyano, nitro, and nitroso; andThe dotted line shows .DELTA..sup.2 or .DELTA..sup.3).
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.