New .beta.-lactams of the general structure: ##STR1## wherein X=O or S; R represents H, loweralkyl, acyl, aryl, or arylloweralkyl; R' is hydrogen, loweralkoxy, loweralkoxyalkyl, loweralkyl, phenylthio or loweralkylmercapto; R" is hydrogen or loweralkyl; and the broken line represents an optional double bond, and certain esters thereof. All compounds are effective antibacterials.

Preparation of renin inhibitors based on the structure of natural renin substrate at residues 6 to 13 from the amino terminal thereof, the inhibitors being polypeptide analogues having in particular an isosteric non-peptide link corresponding to the 10, 11 peptide link of the substrate, and preparation of dipeptide analogues.

An aqueous composition for inhibiting the corrosion of metals placed therein is described. The composition comprises a non-oxidizing acid, and, as a corrosion inhibitor, an effective amount of a 3-di(higher)alkylamino-3-phenylprop-1-yne.

The degradation of enkephalins in a mammalian host is inhibited by administration of an enkephalinase enzyme inhibitor of the formula ##STR1##

New .beta.-lactams of the general structure: ##STR1## wherein R represents H or an acyl moiety known from the penicillin or cephalosporin art, R' is hydrogen, loweralkoxy, loweralkoxyalkyl, loweralkyl, phenylthio or loweralkylmercapto R" is loweralkyl, the broken line represents an optional double bond, and acyloxymethyl esters thereof. All compounds are effective antibacterials.

Novel chemical compounds are provided which selectively inhibit the metabolism of dipeptidase (E.C.3.4.13.11) and therefore are useful in combination with antibacterial products. These chemical compounds are Z-2-(2,2-dimethylcyclo-propanecarboxamido)-.omega.-pyridylthio-2-alkenoic acids (and related arylthio and heterocyclylthio analogs).

An aqueous composition for inhibiting the corrosion of metals placed therein is described. The composition comprises a non-oxidizing acid and, as a corrosion inhibitor, an effective amount of a 3-dialkylamino-3-(substituted phenyl)-prop-1-yne.

An acidic protease inhibitor obtained by allowing a compound of ##STR1## wherein X and Y are L-leucine or L-valine, or its salt, to react with an aluminum compound in a medium containing water and/or an alcohol, and further continuing the reaction after adjusting the pH of the system within a range of 4.5 to 7. The protease can stay long in stomach, have an action to protect ulcerated areas and retain the antiulcer effect for a long period of time.

This invention relates to methods of preventing or reducing the degradation of elastin and other proteins and thereby preventing or retarding the disease states caused by said degradation by administering compounds of the formula: ##STR1## or their pharmacologically acceptable salts.

An anti-corrosive composition is disclosed which comprises the condensate of a polyamine such as diethylenetriamine, triethylenetetramine or aminoethylethanol amine with a 21 or 22 carbon fatty polycarboxylic acid or acid anhydride. The composition may additionally include the condensation products of the above polyamines with either tall oil fatty acids or Rosin S. Propargyl alcohol has been found to enhance the anti-corrosive effects of the composition. The compositions are especially useful i...