Ethyl 1-Boc-3-piperidinecarboxylate

Ionic liquids (ILs) are synthetic solvents used as replacements for volatile organic solvents. Human exposure occurs through dermal or oral routes. In rodents, several ILs were reported to induce dermal toxicity, irritation, and sensitization. Due to the potential for occupational exposure, and industrial use as nonvolatile solvents, 1-ethyl-3-methylimidazolium chloride (EMIM, 6.25% to 50% v/v), 1-butyl-3-methylimidazolium chloride (BMIM, 3.12% to 12.5% v/v), 1-butyl-1-methylpyrrolidinium chloride (BMPY, 0.825% to 6.25% v/v), and N-butylpyridinium chloride (NBuPY, 0.825% to 12.5% v/v) were nominated to the National Toxicology Program and evaluated for skin sensitization. The test compound was applied to the ears of female BALB/c mice daily for 3 days in a primary irritancy (IRR)/local lymph node assay (LLNA). Sensitization was assessed in vitro in the direct peptide reactivity assay (DPRA), KeratinoSens™ assay, and human cell line activation test (h-CLAT). In the LLNA, the butylated ILs, BMIM, and BMPY were more potent than NBuPY (butylated) or EMIM (ethylated), which was neither an irritant nor a sensitizer. NBuPY induced skin irritation in vivo at ≥3.12% (p ≤ 0.01), and sensitization in vitro in the KeratinoSens™ assay and h-CLAT, but was negative for sensitization in vivo and in the DPRA. Although SI3 was not achieved, dermal treatment with 12.5% BMIM or 6.25% BMPY increased (p ≤ 0.01) lymph node cell proliferation in the LLNA. In vitro, BMIM was positive for sensitization in the h-CLAT, and BMPY was positive in the h-CLAT and KeratinoSens™ assay; both were negative in the DPRA. Integrated data analyses, weighted toward in vivo data, suggested that BMIM and BMPY may induce weak to mild sensitization.

1-Ethyl-1-nitrosourea (ENU) is a potent monofunctional ethylating agent that has been found to be mutagenic in a wide variety of mutagenicity tests system from viruses to mammalian germ cells. It also has been shown to induce tumors in various organs of mammals. ENU has been used only for research purposes. ENU possesses the dual action of ethylation and carbamoylation. The ethyl group can be transferred to nucleophilic sites of cellular constituents, and the carbonyl group can be transferred to an amino group of protein. ENU is able to produce significant levels of alkylation at oxygens, such as the O6 position of guanine and the O4 position of thymine of DNA. The molecular genetic data obtained from ENU-induced mutants on various species suggest that ENU produces mainly GC-AT transitions and, to a small extent, AT-GC, AT-CG, AT-TA, GC-CG and GC-TA base substitutions. This mutation spectrum of ENU is different from that of 1-methyl-1-nitrosourea, which mainly induces GC-AT transitions. ENU is a most potent mutagen in mouse germ cells, especially in stem-cell spermatogonia. It induces intragenic mutations with high frequency in male mouse germ cells. ENU has been established as a model compound for exploring the effects of chemical mutagenesis on mouse germ cells.

The ethylating agent ethyl methanesulfonate (EMS) is widely used for inducing random point mutations. In Arabidopsis, treatment with EMS causes GC-to-AT transitions with great efficiency: it has been estimated that a population of 50,000 well-mutagenized plants harbors one or more transitions in almost every GC pair of the genome. These properties, combined with ease of use, make EMS a mutagen of choice for genetic screens. Here, we describe a protocol for mutagenizing Arabidopsis seed with EMS. In addition, we briefly consider the germ line sectors typically induced by this treatment, and approaches for estimating the rate of induced mutations.