NEW MATERIAL: 2-Nitroimidazole deriv. of formula I [R1 is H, 2 to 5C alkanoyl, benzoyl; A is formula II, formula III ((a) is 0, 1, 2; (b) is 1 to 4; B is CHR2, NR2, O; X is OH, Cl, Br, -OSO2CH3, formula IV; R2 is H, 1 to 4C alkyl, phenyl, halogen, hydroxy, 1 to 4C alkyl, etc.), formula V, etc.].

EXAMPLE: α-[(2-Nitro-1H-imidazole-1-yl)-methyl]-6-azabicyclo[3,1,0]hexane-6- ethanol.

USE: Used as a radiation sensitivity intensifying agent for the radiation therapy of ulcers. An either oral or intravenous administration method is used at the time of use.

PROCESS: The compd. of formula I is obtd. by bringing, for example, the 2- nitroimidazole of formula VI into reaction with 3-chloro-1,2-epoxypropane, then converting the product to the compd. of formula VII and bringing an aziridine compd. into reaction therewith.