Attached proton test (APT) spectra acquired with residual coupling (termed RECAPT) can be advantageous in assigning 13C NMR spectra of complex natural products. RECAPT was applied to the analysis of the 13C NMR spectra of two terpene marine natural products to illustrate its advantages over APT in situations where peaks are accidentally degenerate, or where large J(CH) values give misleading phase APT peaks.

Chemischer InformationsdienstVolume 4, Issue 37 Isocyclic Compounds ChemInform Abstract: SPECTRAL AND OTHER PROPERTIES OF SOME OXYGENATED DERIVATIVES OF BENZO(A)PYRENE C. R. RAHA, C. R. RAHASearch for more papers by this authorLARRY K. KEEFER, LARRY K. KEEFERSearch for more papers by this authorJAMES LOO, JAMES LOOSearch for more papers by this author C. R. RAHA, C. R. RAHASearch for more papers by this authorLARRY K. KEEFER, LARRY K. KEEFERSearch for more papers by this authorJAMES LOO, JAMES LOOSearch for more papers by this author First published: September 11, 1973 https://doi.org/10.1002/chin.197337233AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article. Volume4, Issue37September 11, 1973 RelatedInformation

Five cyclic nitrosamines, nitrosoazetidine, nitrosopyrrolidine, nitrosopiperidine, nitrosomorpholine, and dinitrosopiperazine, labeled with deuterium and tritium, were injected into rats and then the nucleic acids of the liver were examined for the presence of alkylated bases derived from the nitrosamines. A semiquantitative mass spectrometric method able to detect 25 ng of a base was used. No deuterium-containing alkylated base was detected, although a small radioactive peak was present in the liver RNA from nitrosomorpholine-treated rats. Nitrosomethylcyclohexylamine gave rise to a deuterium-labeled (—CD3) 7-methylguanine in the liver nucleic acids, showing that diazomethane was not an intermediate in its formation, but not in the esophagus nucleic acids, although esophagus is a target organ for this nitrosamine and liver is not. The expected correlation between carcinogenesis by these nitrosamines and alkylation of nucleic acids in vivo was not seen.

Summary Nitrosomethylurea (NMU) and nitrosoethylurea (NEU) were given to rats by injection of 10 and 30 mg, respectively, in 5 ml of 0.9% NaCl solution into the hepatic portal vein. Of 20 animals treated with NMU, 12 developed tumors; 13 of 20 treated with NEU developed tumors; there were tumors in 6 of 20 0.9% NaCl solution controls. Most of the nitrosoalkylurea-treated animals had tumors of more than 1 organ. There seemed to be no predilection for a particular organ, except that 5 NEU-treated animals had brain tumors and 7 had skin tumors; 3 NMU-treated animals had skin tumors. There was no liver cell damage detectable by light microscopy following the treatment. Analysis of liver nucleic acids following similar treatment of rats with deuterium-labeled NMU and NEU showed no detectable alkylation of DNA. However, deuterium-labeled 7-methylguanine was present in the RNA of NMU-treated rats, but no 7-ethylguanine could be detected in the RNA of NEU-treated rats. This difference in ability to alkylate nucleic acids could not be correlated with the similar tumorigenic activity of NMU and NEU. The identification of methyl- d 3 -guanine as the base formed from NMU- d 3 showed that diazomethane was not an intermediate in nucleic acid alkylation by NMU.

AbstractDie Nitrosaminosäuren (I)‐(V) entstehen in hoher Ausbeute unter Bedingungen, wie sie annähernd auch im Säugetiermagen vorliegen, und decarboxylieren in Gegenwart von verdünntem Alkali zu Nitrosaminen.

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTAnalysis of mixtures of isomeric polynuclear hydrocarbons by nuclear magnetic resonance spectrometry. Methylated derivatives of anthracene, benz[.alpha.]anthracene, benzo[c]phenanthrene, and pyreneLarry K. Keefer, Lawrence. Wallcave, James. Loo, and Ruth S. PetersonCite this: Anal. Chem. 1971, 43, 11, 1411–1416Publication Date (Print):August 1, 1971Publication History Published online1 May 2002Published inissue 1 August 1971https://pubs.acs.org/doi/10.1021/ac60305a010https://doi.org/10.1021/ac60305a010research-articleACS PublicationsRequest reuse permissionsArticle Views45Altmetric-Citations6LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access optionsGet e-Alertsclose Get e-Alerts

The N-nitroso derivatives of the amino acids sarcosine, azetidine-2-carboxylic acid, proline, hydroxyproline and pipecolic acid have been prepared and characterized. All five compounds are formed in high yield under conditions approximating those in the mammalian stomach. The nitrosamino acids can be decarboxylated in low yield in the presence of dilute alkali, the product in each case being a nitrosamine. The possible relevance of these findings to the occurrence of human cancer is discussed. The variation of NMR spectral properties with time has shown that four of these nitrosamino acids preferentially crystallize in a conformation in which the C atom bearing the carboxyl group is syn to the nitroso O atom, while nitrosoazetidinecarboxylic acid assumes the anti conformation in the crystal. The carboxyl group of nitrosopipecolic acid strongly prefers the axial orientation.

SINCE it was discovered1 that nitrosodimethylamine givdes rise to alkylated nucleic acids in the liver when injected into rats, and that an alkylated base, 7-methylguanine, can be isolated from these nucleic acids, there has been much evidence of a correlation between carcinogenicity of N-nitrosamines and their transformation in vivo into an alkylating agent2–4. There was evidence that the initial step in the conversion of the nitrosamine to an alkylating agent was an enzymatic oxidative dealkylation to a hypothetical monoalkylnitrosamine which was then converted to a diazoalkane or, by some other route, to a carbonium ion. No evidence of the production of a diazoalkane in this way has been presented, although this possibility has been widely postulated5–8.