Photolysis of nitroso-compounds. Part IV. 1-Chloro-1-nitrosocyclohexane and other geminal chloro-nitroso-compounds

Brian G. Gowenlock, Josef Pfab, Günther Kresze

Research output: Contribution to journalArticle

Abstract

Detailed studies of the photolysis of 1-chloro-1-nitrosocyclohexane are presented. Photolysis in methanol solutions gave hydrochloric acid, methyl nitrite, 1,1-dimethoxycyclohexane, cyclohexanone, and cyclohexanone oxime. 1-Methoxycyclohexene and 6-hydroxyimino-1-methoxycyclohexene were minor products. Photolysis in aprotic solvents afforded 1-chlorocyclohexene, cyclohexanone, and 1,1-dichlorocyclohexane with small amounts of a-chlorocyclohexanone and 1-chloro-1-nitrocyclohexane at low concentrations whereas at high concentrations substantial amounts of cyclohexanone oxime were found. Evidence based on the variation of product distribution with solvent, concentration, and added radical scavengers is presented, which shows that the primary photochemical step consists in C-NO bond cleavage in all solvents. a-Chloronitrones are postulated as intermediates. The importance of solvolysis and other secondary ionic reactions is emphasised. Other studies of the photolysis of geminal chloronitrosoadamantane, 3-chloro-3-nitrosopentane, and 2-chloro-2-nitrosobutane in alcohols are briefly re-examined in the light of the proposed mechanism. In none of these cases have we found any evidence for a carbonyl-like photoreduction.

Original languageEnglish
Pages (from-to)511-518
Number of pages8
JournalJournal of the Chemical Society, Perkin Transactions 2
Issue number5
Publication statusPublished - 1974

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photolysis
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hydrochloric acid
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methanol
alcohol
product

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title = "Photolysis of nitroso-compounds. Part IV. 1-Chloro-1-nitrosocyclohexane and other geminal chloro-nitroso-compounds",
abstract = "Detailed studies of the photolysis of 1-chloro-1-nitrosocyclohexane are presented. Photolysis in methanol solutions gave hydrochloric acid, methyl nitrite, 1,1-dimethoxycyclohexane, cyclohexanone, and cyclohexanone oxime. 1-Methoxycyclohexene and 6-hydroxyimino-1-methoxycyclohexene were minor products. Photolysis in aprotic solvents afforded 1-chlorocyclohexene, cyclohexanone, and 1,1-dichlorocyclohexane with small amounts of a-chlorocyclohexanone and 1-chloro-1-nitrocyclohexane at low concentrations whereas at high concentrations substantial amounts of cyclohexanone oxime were found. Evidence based on the variation of product distribution with solvent, concentration, and added radical scavengers is presented, which shows that the primary photochemical step consists in C-NO bond cleavage in all solvents. a-Chloronitrones are postulated as intermediates. The importance of solvolysis and other secondary ionic reactions is emphasised. Other studies of the photolysis of geminal chloronitrosoadamantane, 3-chloro-3-nitrosopentane, and 2-chloro-2-nitrosobutane in alcohols are briefly re-examined in the light of the proposed mechanism. In none of these cases have we found any evidence for a carbonyl-like photoreduction.",
author = "Gowenlock, {Brian G.} and Josef Pfab and G{\"u}nther Kresze",
year = "1974",
language = "English",
pages = "511--518",
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publisher = "Royal Society of Chemistry",
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Photolysis of nitroso-compounds. Part IV. 1-Chloro-1-nitrosocyclohexane and other geminal chloro-nitroso-compounds. / Gowenlock, Brian G.; Pfab, Josef; Kresze, Günther.

In: Journal of the Chemical Society, Perkin Transactions 2, No. 5, 1974, p. 511-518.

Research output: Contribution to journalArticle

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T1 - Photolysis of nitroso-compounds. Part IV. 1-Chloro-1-nitrosocyclohexane and other geminal chloro-nitroso-compounds

AU - Gowenlock, Brian G.

AU - Pfab, Josef

AU - Kresze, Günther

PY - 1974

Y1 - 1974

N2 - Detailed studies of the photolysis of 1-chloro-1-nitrosocyclohexane are presented. Photolysis in methanol solutions gave hydrochloric acid, methyl nitrite, 1,1-dimethoxycyclohexane, cyclohexanone, and cyclohexanone oxime. 1-Methoxycyclohexene and 6-hydroxyimino-1-methoxycyclohexene were minor products. Photolysis in aprotic solvents afforded 1-chlorocyclohexene, cyclohexanone, and 1,1-dichlorocyclohexane with small amounts of a-chlorocyclohexanone and 1-chloro-1-nitrocyclohexane at low concentrations whereas at high concentrations substantial amounts of cyclohexanone oxime were found. Evidence based on the variation of product distribution with solvent, concentration, and added radical scavengers is presented, which shows that the primary photochemical step consists in C-NO bond cleavage in all solvents. a-Chloronitrones are postulated as intermediates. The importance of solvolysis and other secondary ionic reactions is emphasised. Other studies of the photolysis of geminal chloronitrosoadamantane, 3-chloro-3-nitrosopentane, and 2-chloro-2-nitrosobutane in alcohols are briefly re-examined in the light of the proposed mechanism. In none of these cases have we found any evidence for a carbonyl-like photoreduction.

AB - Detailed studies of the photolysis of 1-chloro-1-nitrosocyclohexane are presented. Photolysis in methanol solutions gave hydrochloric acid, methyl nitrite, 1,1-dimethoxycyclohexane, cyclohexanone, and cyclohexanone oxime. 1-Methoxycyclohexene and 6-hydroxyimino-1-methoxycyclohexene were minor products. Photolysis in aprotic solvents afforded 1-chlorocyclohexene, cyclohexanone, and 1,1-dichlorocyclohexane with small amounts of a-chlorocyclohexanone and 1-chloro-1-nitrocyclohexane at low concentrations whereas at high concentrations substantial amounts of cyclohexanone oxime were found. Evidence based on the variation of product distribution with solvent, concentration, and added radical scavengers is presented, which shows that the primary photochemical step consists in C-NO bond cleavage in all solvents. a-Chloronitrones are postulated as intermediates. The importance of solvolysis and other secondary ionic reactions is emphasised. Other studies of the photolysis of geminal chloronitrosoadamantane, 3-chloro-3-nitrosopentane, and 2-chloro-2-nitrosobutane in alcohols are briefly re-examined in the light of the proposed mechanism. In none of these cases have we found any evidence for a carbonyl-like photoreduction.

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