Antibiotic activity is exhibited by .beta.-lactams having an ##STR1## substituent (and analogs thereof) in the 1-position and an acylamino substituent in the 3-position.
Novel quinolin-6-ylthioacetamides and quinolin-6-ylpropanamides have been prepared. They are linker isomers of quinolin-6-yloxyacetamide fungicides in which the oxygen atom of the O,S-acetal in the original lead structures has been replaced by either a sulfur atom or a methylene bridge. The Newman–Kwart rearrangement proved to be highly useful for the concise synthesis of the quinolin-6-ylthioacetamides