出典:Wikipedia
出典:『Wikipedia』 (2011/03/06 08:58 UTC 版)
A lactam (the noun is a portmanteau of the words lactone + amide) is a cyclic amide. Prefixes indicate how many carbon atoms (apart from the carbonyl moiety) are present in the ring: β-lactam (2 carbon atoms outside the carbonyl, 4 ring atoms in total), γ-lactam (3 and 5), δ-lactam (4 and 6). Beta β, gamma γ and delta δ are the second, third and fourth letters in the alphabetical order of the Greek alphabet, respectively.