Abstract: Certain 2-azacycloalkylthio-2-penem-3-carboxylic acid compounds are useful as antibacterials for treating mammals and have the formula ##STR1## or a pharmaceutically acceptable salt thereof, wherein: R is ##STR2## A is alkylene having 2-4 carbon atoms, alkylene having 2-4 carbon atoms wherein a carbon atom has an oxo substituent or alkylene having 2-4 carbon atoms wherein a methylene is replaced by oxygen, S(O).sub.m, or N--R.sub.3 ;B is carbonyl, thiocarbonyl, methylene or imine;R.sub.1 is hydrogen or forms an ester group which is hydroyzed in vivo;R.sub.2 is hydrogen, formyl, alkylcarbonyl, N-alkylaminocarbonyl, N-alkylaminosulfonyl, aminosulfonyl, aminocarbonyl, alkoxycarbonyl having 2-5 carbon atoms, alkylsulfonyl, alkyl, or alkyl substituted by aminocarbonyl, alkyl--S(O).sub.m --, hydroxyl, amino, alkylcarbonylamino, formamido or alkylsulfonylamino, wherein each alkyl has 1-4 carbon atoms;R.sub.

Abstract: Certain 2-substituted-2-penem-3-carboxylic acid compounds and pharmaceutically-acceptable salts thereof can be prepared from the appropriate xanthate or trithiocarbonate by desulfurization and addition of an electrophilic sulfur compound followed by halogenation and ring closure. The corresponding desulfurized and halogenated olefinic intermediates are disclosed.

Abstract: Certain substituted-2-penem-3-carboxylic acid compounds, and pharmaceutically-acceptable salts thereof, can be prepared from the appropriate xanthate or trithiocarbonate by desulfurization, followed by halogenation and ring closure. The corresponding desulfurized and halogenated intermediates are disclosed.

Abstract: Certain 2-alkylthio-2-penem-3-carboxylic acid compounds are useful as antibacterials for treating mammals.

Abstract: Certain 2-dioxacycloalkylthio-2-penem-3-carboxylic acid compounds are useful as antibacterials for treating mammals and have the formula ##STR1## or a pharmaceutically acceptable salt thereof, wherein: R is ##STR2## A is carbonyl, methylene or thiocarbonyl; B is alkylene having 2-5 carbon atoms;alk is alkylene having 1-6 carbon atoms;R.sub.1 is hydrogen or a group which results in an ester which is hydrolyzable in vivo; andn is zero or one.

Abstract: Certain 2-substituted-2-penem-3-carboxylic acid compounds and pharmaceutically-acceptable salts thereof can be prepared from the appropriate xanthate or trithiocarbonate by desulfurization and addition of an electrophilic sulfur compound followed by halogenation and ring closure. The corresponding desulfurized and halogenated olefinic intermediates are disclosed.

Abstract: Salts of readily hydrolyzable esters of 6-alpha-(aminomethyl)penicillanic acid 1,1-dioxide and (a) prodrug forms of ampicillin and amoxicillin or (b) ampicillin and amoxicillin and a dibasic acid are readily absorbed following oral adminstration, and are useful in treating bacterial infections.

Abstract: 6-Beta-sulfonyloxypenicillanic acid derivatives are novel beta-lactamase inhibitors, useful in combination with standard beta-lactam antibiotics against bacterial strains otherwise resistant to said beta-lactam antibiotics by dint of their production of beta-lactamases.

Abstract: 6-.beta.-Substituted penicillanic acids and derivatives thereof as useful enhancers of the effectiveness of several .beta.-lactam antibiotics against many .beta.-lactamase producing bacteria, and 6-.beta.-substituted penicillanic acid derivatives wherein the carboxy group is protected by a conventional penicillin carboxy protecting group as useful intermediates leading to said synergistic agents. A process for converting 6,6-disubstituted penicillanic acid derivatives to the corresponding 6-.beta.-substituted penicillanic acid congeners.

Abstract: Antibacterial agents in which a penicillin and a beta-lactamase inhibitor are linked by means of a bis-hydroxymethyl carbonate bridge are of the formula: ##STR1## and pharmaceutically acceptable acid addition salts thereof, wherein R.sup.1 is hydrogen, hydroxy, certain acyloxy or certain alkoxycarbonyloxy groups, a method for their use, pharmaceutical compositions thereof, and intermediates useful in their production.

Abstract: 6- .alpha.-(Amidino- and imidoylaminoalkanoylamino)aracylamino!-penicillanic acids and synthetic methods for the preparation thereof.

Abstract: 6-[.alpha.-(Amidino- and imidoylaminoalkanoylamino)aracylamino]-penicillanic acids and synthetic methods for the preparation thereof.

Abstract: 6-[.alpha.-(Amidino- and imidoylaminoalkanoylamino)aracylamino]-penicillanic acids and synthetic methods for the preparation thereof.

Abstract: 6-[.alpha.-(.omega.-GUANIDINOALKANOYLAMIDO)ACYLAMIDO]PENICILLANIC ACIDS, THE NON-TOXIC SALTS AND ESTERS THEREOF ARE USEFUL AS ANTIBACTERIAL AGENTS, THERAPEUTIC AGENTS IN ANIMALS, INCLUDING MAN, OF PARTICULAR VALUE AGAINST GRAM-NEGATIVE BACTERIA, AND AS ANIMAL FEED NUTRITIONAL SUPPLEMENTS.

Abstract: 6-[.alpha.-(Amidino- and imidoylaminoalkanoylamino)aracylamino]-penicillanic acids and synthetic methods for the preparation thereof.

Abstract: 6-[.alpha.-(.omega.-GUANIDINOALKANOYLAMIDO)ACYLAMIDO]PENICILLANIC ACIDS, THE NON-TOXIC SALTS AND ESTERS THEREOF ARE USEFUL AS ANTIBACTERIAL AGENTS, THERAPEUTIC AGENTS IN ANIMALS, INCLUDING MAN, OF PARTICULAR VALUE AGAINST GRAM-NEGATIVE BACTERIA, AND AS ANIMAL FEED NUTRITIONAL SUPPLEMENTS.