title: Reactivity of the mutagen 1,4-dinitro-2-methylpyrrole as an alkylating agent.
abstract: The formation of chemical species with DNA-damaging and mutagenic activity for bacterial test systems was detected in sorbic acid-nitrite mixtures. 1,4-Dinitro-2-methylpyrrole (NMP), one the main products resulting from the reaction between sorbic acid and nitrite, has mutagenic properties, and here its alkylating capacity was investigated. The conclusions drawn are as follows: (i) In aqueous medium, after the addition of a hydroxide ion and the subsequent loss of nitrite, NMP affords 5-methyl-3-nitro-1H-pyrrol-2-ol. This species is in equilibrium with 5-methyl-3-nitro-1H-pyrrol-2(5H)-one, the effective alkylating agent responsible for the genotoxic capacity of NMP; (ii) 5-methyl-3-nitro-1H-pyrrol-2(5H)-one alkylates 4-(p-nitrobenzyl)pyridine (NBP), a molecule with nucleophilic characteristics similar to those of DNA bases, forming an adduct (AD; epsilon = 1.14 x 10(4) M(-1) cm(-1)); (iii) The calculated energy barrier for the alkylation of NBP for NMP and the value of the fraction of alkylating agent forming the adduct are consistent with the observed mutagenicity of NMP; (iv) The reactivity of NMP can be explained in terms of the instability of the N-NO(2) bond as well as the effect of this group on aromaticity.
authors.affiliation: Departamento de Química Fisica, Universidad de Salamanca, E-37008 Salamanca, Spain.
authors.forename: M Teresa
authors.initials: MT
authors.lastname: Pérez-Prior
authors.forename: Rafael
authors.initials: R
authors.lastname: Gómez-Bombarelli
authors.forename: Marina
authors.initials: M
authors.lastname: González-Pérez
authors.forename: José A
authors.initials: JA
authors.lastname: Manso
authors.forename: M Pilar
authors.initials: MP
authors.lastname: García-Santos
authors.forename: Emilio
authors.initials: E
authors.lastname: Calle
authors.forename: Julio
authors.initials: J
authors.lastname: Casado
mesh_terms: D000477:Alkylating Agents / Q000737:chemistry* / Q000633:toxicity; D002851:Chromatography, High Pressure Liquid; D004247:DNA / Q000737:chemistry* / Q000378:metabolism; D004249:DNA Damage; D009682:Magnetic Resonance Spectroscopy; D013058:Mass Spectrometry; D008826:Microbial Sensitivity Tests; D009153:Mutagens; D009154:Mutation / Q000187:drug effects; D009573:Nitrites / Q000737:chemistry*; D011758:Pyrroles / Q000737:chemistry* / Q000633:toxicity; D012475:Salmonella; D013011:Sorbic Acid / Q000737:chemistry*; D013056:Spectrophotometry, Ultraviolet; D013329:Structure-Activity Relationship
chemical_list: D000477:Alkylating Agents; D009153:Mutagens; D009573:Nitrites; D011758:Pyrroles; D004247:DNA; C028453:2-methyl-1,4-dinitropyrrole; D013011:Sorbic Acid