1. A 2,6-dioxopiperidine selected from the group consisting of (a) a compound of the formula: <；CHEM>； in which: one of X and Y is C=O and the other of X and Y is C=O or CH2； (i) each of R<；1>；, R<；2>；, R<；3>；, and R<；4>；, independently of the others, is halo, alkyl of 1 to 4 carbon atoms, or alkoxy of 1 to 4 carbon atoms or (ii) one of R<；1>；, R<；2>；, R<；3>；, and R<；4>； is -NHR<；5>； and the remaining of R<；1>；, R<；2>；, R<；3>；, and R<；4>； are hydrogen； R<；5>； is hydrogen, alkyl of 1 to 8 carbon atoms, or CO-R<；7>；-CH(R<；10>；)NR<；8>；R<；9>；； R<；6>； is hydrogen, alkyl of 1 to 8 carbon atoms, benzo, chloro, or fluoro； R<；7>； is m-phenylene or p-phenylene or -(CnH2n)- in which n has a value of 0 to 4； each of R<；8>； and R<；9>； taken independently of the other is hydrogen or alkyl of 1 to 8 carbon atoms, or R<；8>； and R<；9>； taken together are tetramethylene, pentamethylene, hexamethylene, or -CH2CH2XCH2CH2- in which X is -O-, -S- or -NH-； R<；10>； is hydrogen, alkyl of 1 to 8 carbon atoms, or phenyl； and (b) the acid addition salts of said compounds which contain a nitrogen atom capable of being protonated.
