Nitrosoureas analysis

Analysis of reaction mixtures for 1-propanol and 2-propanol following incubation of NDPA with various rat liver fractions in the presence of an NADPH-generating system is shown in Table I ( ). Presence of microsomes leads to production of both alcohols, but there was no propanol formed with either the soluble enzyme fraction or with microsomes incubated with SKF-525A (an inhibitor of cytochrome P450-dependent oxidations). The combined yield of propanols from 280 ymoles of NDPA was 6.1 ymoles and 28.5 ymoles for the microsomal pellet and the 9000 g supernatant respectively. The difference in the ratio of 1- to 2-propanol in the two rat liver fractions may be due to differences in the chemical composition of the reaction mixtures (2) Subsequent experiments have shown that these ratios are quite reproducible. For comparison, Table I also shows formation of propanols following base catalyzed decomposition of N-propyl-N-nitrosourea. As expected (10,11), both propanol isomers were formed, the total yield in this case being almost quantitative. 

OS 49] [R 17] [R 26] [P 36] At almost quantitative conversion, yields of 90% of two (in a first run) unidentified products and of 10% N,N -diethylurea were reported, accompanied by small amoimts of the mono-product [38], AH products no longer contained any C=S moiety, hence were somehow attacked via a nucleophilic route. By subsequent MS and IR analysis, the two main products were identified as N,N -diethyl-N-nitrosourea and, probably, N,N -diefhyl-N,N -dinitrosourea. By optimization of the [P 23] procedure, 100% selectivity for the nitration of N,N -diethylurea to N,N -diethylurea was achieved. 

RoscOE, J.P. and Claisse, P.J. (1978). Analysis of N-ethyl-N-nitrosourea induced brain carcinogenesis by sequential culturing during the latent pe iod. I. Morphology and tumorigenicity of the cultured ceUs and their growth in agar, J. NatL Cancer Inst. 61,381. 

Dobrovolsky, V. N., Chen, X, and Heflich, R. H. (1999b). Molecular analysis of in vivo mutations induced by V-ethyl-V-nitrosourea in the autosomal Xk and the X-linked Hprt genes of mouse lymphocytes. Environ Mol Mutagen 34, 30-38. 

Diazoethane made from N-ethyl-N-nitrosourea [59] in ethereal solution (0.5 ml) was added and the solution was allowed to stand at 30 °C for 30 minutes. The solution was again blown down with nitrogen, and the residue was taken up in benzene for analysis by GC—ECD [60]. 

Tatematsu M, Fukami H, Yamamoto M, et al. Clonal analysis of glandular stomach carcinogenesis in C3H/HeN-BALB/c chimeric mice treated with N-methyl-N-nitrosourea. Cancer Lett 1994 83 37-42. 

Analysis of Reagent Purity diazomethane is titrated by adding a known quantity of benzoic acid to an aliquot of the solution such that the solution is colorless and excess benzoic acid remains. Water is then added, and the amount of benzoic acid remaining is back-titrated with NaOH solution. The difference between the amount of acid added and the amount remaining reveals the amount of active diazomethane present in the aliquot. Preparative Methods diazomethane is usually prepared by the decomposition of various derivatives of IV-methyl-IV-nitrosoamines. Numerous methods of preparation have been described, but the most common and most frequently employed are those which utilize N-Methyl-N-nitroso-p-toluenesulfonamide (Diazald 1), l-Methyl-3-nitro-l-nitrosoguanidine (MNNG, 2), or N-methyl-N-nitrosourea (3). ... 

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