Abstract: A process for preparing a &bgr;-hydroxyester comprising reducing a &bgr;-keto ester in the presence of a salt of ammonium borohydride.

Abstract: The present invention is directed to a process for preparing an exo-methylenepenam compound wherein a cephem compound is reduced with a metal having a standard oxidation-reduction potential of up to −0.3 (V/SCE) in an amount of at least one mole per mole of the cephem compound and with a metal compound having a higher standard oxidation reduction potential than the metal and in an amount of 0.

Abstract: The present invention provides a process for preparing an exo-methylenepenam compound represented by the general formula (5) characterized in that a &bgr;-lactam halide compound represented by the general formula (2) is subjected to an electroreduction process to obtain the exo-methylenepenam compound.

Abstract: A process for preparing an allenyl .beta.-lactam compound represented by the formula (4), characterized by reacting the hydroxyl group of a .beta.-lactam compound represented by the formula (1) with a reactive functional group derivative of sulfonic acid represented by the formula (2) to convert the compound of the formula (1) to a .beta.-lactam compound represented by the formula (3), thereafter reacting the resulting .beta.-lactam compound with a basic anion exchange resin of the type having a tertiary organic base fixed to the resin and isolating the resulting allenyl .beta.

Abstract: The present invention provides a process for preparing an exo-methylenepenam compound represented by the general formula (5) characterized in that a .beta.-lactam halide compound represented by the general formula (2) is reduced with a metal having a standard oxidation-reduction potential of up to -0.3 (V/SCE) in an amount of at least one mole per mole of the halide compound and with a metal compound having a higher standard oxidation-reduction potential than the metal in an amount of 0.0001 to 10 moles per mole of the halide compound, or is subjected to an electroreduction process to obtain the exo-methylenepenam compound.

Abstract: A process for preparing a .beta.-lactam halide compound represented by the formula (2) characterized by halogenating the allenyl group of an allenyl .beta.-lactam compound represented by the formula (1) with a cupric halide and a metal halide to obtain the .beta.-lactam halide compound ##STR1## wherein R.sup.1 is a hydrogen atom or amino or protected amino, R.sup.2 is a hydrogen atom, halogen atom, lower alkoxyl, lower acyl, or lower alkyl having a hydroxyl group or protected hydroxyl group as a substituent, R.sup.3 is a hydrogen atom or carboxylic acid protecting group, and R.sup.4 is a hydrocarbon group which may have a substituent, or the group --S--S(O)n-Ar, n being 0 to 2, Ar being aryl which may have a substituent ##STR2## wherein R.sup.1, R.sup.2, R.sup.3 and R.sup.4 are the same as defined above, X and Y are each halogen atom.

Abstract: The present invention provides a process for preparing an allenyl .beta.-lactam compound represented by the formula (II) or a process for preparing a 3-halocephem compound of the formula (III) by altering the reaction conditions with use of a .beta.-lactam halide compound represented by the formula (I) serving as the starting material ##STR1## wherein R.sub.1 is a hydrogen atom, amino or protected amino, R.sub.2 is aryl which may have a substituent, n is 0 to 2, R.sub.3 is a hydrogen atom or carboxylic acid protective group, X is a halogen atom, and Y is a halogen atom or a leaving group ##STR2## wherein R.sub.1, R.sub.2, n and R.sub.3 are as defined above ##STR3## wherein R.sub.1, R.sub.3 and X are as defined above.

Abstract: The present invention provides a process for preparing 3-norcephem compound represented by the formula (2), characterized in that a hydride reagent is acted on a halogenated .beta.-lactam compound represented by the formula (1) in the presence of a cuprous compound ##STR1## wherein R.sub.1 is a hydrogen atom, amino group or protected amino group, R.sub.2 is an aryl or substituted aryl, n is 0 to 2, R.sub.3 is a hydrogen atom or carboxylic acid protective group, X is a halogen atom, and Y is a halogen atom or a leaving group ##STR2## wherein R.sub.1 and R.sub.3 are as defined above.

Abstract: A process for preparing a 3-alkoxymethylcephem compound represented by the formula (II) ##STR1## where R.sub.1 is a hydrogen atom, amino or protected amino, R.sub.3 is a hydrogen atom or carboxylic acid protective group and R.sub.4 is lower alkyl, which process is characterized in that a 3-thiomethylcephem compound represented by the formula (I) ##STR2## where R.sub.1 and R.sub.3 are as defined above and R.sub.2 is aryl which may have a substituent, is electrolytically oxidized in an electrooxidation reaction system in the presence of a lower alcohol using as a positive electrode, a material selected from the group consisting of platinum, tin, aluminum, stainless steel, nickel, lead oxide, carbon, iron oxide and titanium, to obtain the 3-alkoxymethylcephem compound.

Abstract: The invention provides a process for preparing an allenyl .beta.-lactam of formula (4), by reacting the hydroxyl group of a .beta.-lactam of formula (1) with a reactive derivative of sulfonic acid of formula (2) to convert the compound of formula (1) to a .beta.-lactam of formula (3), thereafter reacting the resulting .beta.-lactam with a basic anion exchange resin of the type having a tertiary organic base fixed to the resin and isolating the allenyl .beta.-lactam of formula (4) with stability and high purity in a high yield.The invention also provides a process for preparing an allenyl .beta.-lactam of formula (4), by reacting the hydroxyl group of a .beta.-lactam compound of formula (1) with a reactive derivative of sulfonic acid of formula (2) to convert the compound of the formula (1) to a .beta.-lactam compound of formula (3), thereafter reacting the resulting .beta.-lactam of formula (3) with a tertiary organic base to convert the compound (3) to the allenyl .beta.

Abstract: A process for preparing a 3-halogenated cephem derivative represented by the formula (2), characterized by causing a halogenating reagent to act on an allenyl .beta.-lactam compound represented by the formula (1) in the presence of a cuprous salt or cupric salt to obtain the 3-halogenated cephem derivative ##STR1## wherein R.sup.1 is a hydrogen atom, amino or protected amino, R.sup.2 is a hydrogen atom, halogen atom, lower alkoxyl, lower acyl, lower alkyl, lower alkyl having at least one selected from hydroxyl and protected hydroxyl as a substituent, hydroxyl or protected hydroxyl, R.sup.3 is a hydrogen atom or carboxylic acid protecting group, R.sup.4 is an aromatic compound residue which may have a substituent or nitrogen-containing aromatic heterocyclic compound residue which may have a substituent, and n is 0 to 2 ##STR2## wherein R.sup.1, R.sup.2 and R.sup.3 are as defined above, X is a halogen atom.

Abstract: The present invention provides a process for producing a .beta.-lactam halide compound represented by the general formula (2) which process is characterized in that the hydroxyl group of a .beta.-lactam halide compound represented by the general formula (1) is substituted with a halogen atom or a leaving group.

Abstract: The object of the invention is to provide a .beta.-lactam compound and a 2-substituted methyl-3-cephem compound, both of which are of value as intermediates for the synthesis of cephem antibiotics.The .beta.-lactam compound of the invention may be represented by the general formula ##STR1## wherein R.sup.1 represents a protected amino group, for instance; R.sup.2 represents hydrogen, for instance; R.sup.3 represents hydrogen or a carboxy-protecting group; R.sup.4 represents an aryl group which may be substituted; R.sup.5 represents an alkenyl group which may be substituted, for instance. The 2-substituted methyl-3-cephem compound of the invention may be represented by the general formula ##STR2## wherein R.sup.1, R.sup.2 and R.sup.3 are as defined above; R.sup.6 represents an aryl group which may be substituted.

Abstract: The present invention provides a process for preparing a cephem compound represented by the general formula (3) characterized in that an allenyl-.beta.-lactam compound represented by the general formula (1) is reacted with an organotin compound represented by the general formula (2) in the presence of a monovalent copper salt ##STR1## wherein R.sup.1 is a hydrogen atom, halogen atom, amino or protected amino, R.sup.2 is a hydrogen atom, halogen atom, lower alkoxyl, lower acyl, lower alkyl, lower alkyl having hydroxyl or protected hydroxyl as a substituent, hydroxyl or protected hydroxyl, or R.sup.1 and R.sup.2 form=0 when taken together, R.sup.3 is a hydrogen atom or carboxylic acid protecting group, R.sup.4 is aryl, aryl having a substituent, nitrogen-containing aromatic heterocyclic group or nitrogen-containing aromatic heterocyclic group having a substituent, and m is 0 or 2,(R.sup.5).sub.n --Sn(R.sup.6).sub.4--n (2)wherein R.sup.

Abstract: A penam derivative of the general formula ##STR1## wherein R.sup.1 means hydrogen, halogen, amino or protected amino; R.sup.2 means hydrogen, halogen, lower alkoxy, lower acyl, lower alkyl, hydroxy- or protected hydroxy-substituted lower alkyl, hydroxy or protected hydroxy, or R.sup.1 and R.sup.2 may jointly represent oxo; R.sup.3 means hydrogen or a carboxy-protecting group; R.sup.4 means hydrogen; R.sup.5 means a group of the formula --CH.sub.2 Y where Y means halogen, --N.sub.3, --ONO.sub.2, --OR.sup.6, --OCOR.sup.6, --SCSOR.sup.6, --SCSN(R.sup.6).sub.2, --SR.sup.6, --SO.sub.2 R.sup.6, --NHR.sup.6, --N(R.sup.6).sub.2 or a substituted or unsubstituted nitrogen-containing heterocyclic group having a free valence on nitrogen; R.sup.6 means a lower alkyl, aryl or heterocyclic group which is substituted or unsubstituted; or R.sup.4 and R.sup.5 may jointly represent .dbd.CH.sub.2 ; n means 0, 1 or 2; provided, however, that where R.sup.4 and R.sup.5 jointly represent .dbd.CH.sub.2, n is not equal to 0.

Abstract: The object of the invention is to provide a .beta.-lactam compound and a 2-substituted methyl-3-cephem compound, both of which are of value as intermediates for the synthesis of cephem antibiotics.The .beta.-lactam compound of the invention may be represented by the general formula ##STR1## wherein R.sup.1 represents a protected amino group, for instance; R.sup.2 represents hydrogen for instance; R.sup.3 represents hydrogen or a carboxy-protecting group; R.sup.4 represents an aryl group which may be substituted; R.sup.5 represents an alkenyl group which may be substituted, for instance. The 2-substituted methyl-3-cephem compound of the invention may be represented by the general formula ##STR2## wherein R.sup.1, R.sup.2 and R.sup.3 are as defined above; R.sup.6 represents an aryl group which may be substituted.

Abstract: The present invention provides a thiazolinoazetidinone derivative represented by the formula ##STR1## wherein R.sup.1 is phenyl having or not having substituent(s), methyl having or not having substituent(s) or ##STR2## group, R.sup.3 being phenyl having or not having substituent(s), and R.sup.2 is a hydrogen atom or carboxylic acid protective group, and a process for preparing the same.The present invention further provides a process for preparing a 2-exo-methylenepenam derivative characterized by hydrolyzing the thiazoline ring of a thiazolinoazetidinone derivative of the above formula (1) to effect recyclization and obtain a 2-exo-methylenepenam derivative represented by the formula ##STR3## wherein R.sup.1 and R.sup.2 are as defined above.

Abstract: The present invention provides a thiazolinoazetidinone derivative represented by the formula ##STR1## wherein R.sup.1 is phenyl having or not having substituent(s), methyl having or not having substituent(s) or ##STR2## group, R.sup.3 being phenyl having or not having substituent(s), and R.sup.2 is a hydrogen atom or carboxylic acid protective group, and a process for preparing the same.The present invention further provides a process for preparing a 2-exo-methylenepenam derivative characterized by hydrolyzing the thiazoline ring of a thiazolinoazetidinone derivative of the above formula (1) to effect recyclization and obtain a 2-exo-methylenepenam derivative represented by the formula ##STR3## wherein R.sup.1 and R.sup.2 are as defined above.

Abstract: The present invention provides a process for preparing a cephem derivative characterized in that an allenyl .beta.-lactam compound represented by the formula (1) ##STR1## wherein R.sup.1 is amino or protected amino, R.sup.2 is a hydrogen atom or lower alkoxyl, R.sup.3 is a hydrogen atom or carboxylic acid protecting group and X is the group --SO.sub.2 R.sup.4 or --SR.sup.4, R.sup.4 being substituted or unsubstituted aryl or substituted or unsubstituted nitrogen-containing aromatic heterocyclic group is reacted with a nucleophilic agent to obtain the derivative, the cephem derivative being represented by the formula (2) ##STR2## wherein R.sup.1, R.sup.2 and R.sup.3 are as defined above, and Y is the residue of the nucleophilic agent.

Abstract: The present invention provides a process for preparing a 2-exo-methylenepenam derivative represented by the formula (2), the process being characterized by reacting an allenyl .beta.-lactum compound represented by the formula (1) with a metallic reducing agent, in which R.sup.1, R.sup.2, R.sup.3 and X are defined in the specification.