Abstract: Cephalosporin compounds shown by the general formula ##STR1## wherein R.sub.1 represents hydrogen atom or an amino group; R.sub.2 and R.sub.3, which may be the same or different, each represents hydrogen atom, a hydroxy group, an oxo group, a lower alkyl group, or a lower alkoxy group; R.sub.4 represents a hydrogen atom or a lower alkoxy group; R.sub.5 represents an acetoxy group or --S--R.sub.6 (wherein R.sub.6 represents a 5- or 6-membered nitrogen-containing heterocyclic group which can be substituted by a lower alkyl group or lower alkoxy group); and A represents a monocyclic or bicyclic heterocyclic ring containing one or two atoms selected from the group consisting of nitrogen, oxygen and a sulfur atom; and pharmaceutically acceptable nontoxic salts thereof.These compounds have excellent antimicrobial activity against various microorganisms including resistant bacteria and are used for the treatment of bacterial infections of animals including human beings.

Abstract: A novel cephalosporin derivative having at the 3-position of the cephem ring a heterocyclic thiomethyl group having a carboxy group or a sulfo group and at the 7-position of the cephem ring, an .alpha.-heterocyclic acylaminophenylacetamide group. The compounds of this invention have excellent antibacterial activity against Pseudomonas and Proteus strains of bacteria.

Abstract: An improved process of preparing a 6-alkoxy-substituted penicillin or penicillin sulfoxide is disclosed. This process comprises adding a halogenating agent to penicillin or penicillin sulfoxide while cooling, and then adding an alkali metal alcoholate to the hydrogenation product in the presence of an alcohol corresponding to the alcoholate.

Abstract: Novel 7-(.alpha.-hydroxy-substituted pyridylcarboxamido-.alpha.-phenylacetamido)-3-substituted thiomethyl-.DELTA..sup.3 -cephem-4-carboxylic acid derivatives are disclosed. The compounds of this invention have high water solubility and show excellent antibacterial activities against various strains of Pseudomonas and Proteus.

Abstract: The ampicillin derivatives represented by the general formula ##SPC1##Wherein R represents ##SPC2##Wherein R' represents a hydrogen atom, a methyl group, or an ethyl group and A and B each represents a hydrogen atom, a hydroxyl group, a methyl group, a methoxy group, a nitro group, or a halogen atom and further said B may combine with A on the carbon atom at the position to form ##SPC3##Group (where in Z represents --CH=N-- or --CH=CH-- and an R.sup.2 represents a hydrogen atom, a hydroxyl group, a phenyl group, a methyl group, an ethyl group, a methoxy group, an ethoxyl group, a methylthio group, a trifluoromethyl group, a halogen atom, a nitro group, an acetyl group, an acetamido group, a ethoxycarbonyloxy group, or a methylsulfonyl group and further R.sub.2 and ##SPC4##May form a thiazole, isothiazolo, pyrrolo, furo, or benzo fused ring which may be substituted by an oxo group, a methyl group, or an acetyl group) and the dotted line means an arbitrary double bond, ##SPC5##Wherein R.sup.3 and R.sup.

Abstract: The oxofuryl ester derivatives of 6-(.alpha.-amino-phenylacetamido)penicillanic acid, 7-(.alpha.-aminophenylacetamido)-cephalosporanic acid, or 7-(.alpha. -aminophenylacetamide)desacetoxycephalosporanic acid represented by the general formula ##SPC1##Wherein A represents ##SPC2##Wherein R.sup.1 and R.sup.2, which may be the same or different, each represents a hydrogen atom or a lower alkyl group, said R.sup.1 and R.sup.2 may form together a 1,3-butadienylene group, R.sup.3 represents a hydrogen atom or an acetoxy group, andMeans a single bond or a double bond, and acid addition salts of them. When those compounds are orally administered, they are readily absorbed by the intestines and show antibacterial activity by splitting their ester bonds. The rate of absorption of the compounds by the intestines are higher and the toxic property of them is less than those of known compounds similar to the above compounds.

Abstract: The penicillin derivatives represented by the formula ##SPC1##Wherein ring A represents a 5- or 6-membered single or fused ring which may contain one or more nitrogen atoms, an oxygen atom, or a sulfur atom; R.sup.1, R.sup.2, and R.sup.3, which may be the same or different, each represents a hydrogen atom, a hydroxy group, a lower alkyl group, a nitro group, a halogen atom, or an oxo group; and B represents a p-hydroxyphenyl group or a 1,4-cyclohexadien -1-yl group, and their nontoxic pharmaceutically acceptable salts.The compounds are antibiotics having excellent antibacterial activity in particular with respect to the Pseudomonas genus.

Abstract: A process for the preparation of cephalosporanic acid derivatives represented by the formula ##SPC1##Wherein R.sub.1 and R.sub.2, which may be the same or different, each represents a univalent group other than a hydrogen atom, said R.sub.1 and R.sub.2 may be combined to form a divalent group and A represents a divalent group represented by the formulae ##SPC2##Wherein R.sub.3 represents a hydrogen atom or a group which does not contribute to the reaction, which comprises heating a penicillin sulfoxide derivative represented by the formula ##SPC3##Wherein R.sub.1, R.sub.2 and R.sub.3 are as defined above.The cephalosporanic acid derivatives prepared by the process of this invention are useful as a starting material for the preparation of antibacterials.