XCIV.—The constitution of carbamides. Part IX. The interaction of nitrous acid and mono-substituted ureas. The preparation of diazomethane, diazoethane, diazo-n-butane, and diazoisopentane from the respective nitrosoureas

Werner, Emil Alphonse

doi:10.1039/ct9191501093

Cited by 66 publications

(22 citation statements)

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“…This suggests that bladder carcinogenesis has many characteristics in common with the classical multistage model derived from studies on the mouse epidermis (Berenblum, 1974). Evidence has accumulated that the multistage model is applicable to carcinogenesis in the liver (Peraino et at., 1973;Farber & Solt, 1978;Pitot et al, 1978) and possibly in the colon (Reddy et al, 1978) and lung (Witschi & Lock, 1978). Furthermore, epidemiological studies suggest that the development of many human carcinomas also follows a temporal sequence of events (Peto, 1977).…”

Section: Electron Microscopymentioning

confidence: 99%

Induction of bladder cancer in rats by fractionated intravesicular doses of N-methyl-N-nitrosourea

Severs¹,

Barnes²,

Wright³

et al. 1982

Br J Cancer

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Summary.-Experiments were conducted to determine the dose response of rat bladder urothelium to a range of different single and fractionated intravesicular doses of the carcinogen, N-methyl-N-nitrosourea (MNU). A dose-related response of bladder-tumour incidence to single graded doses of MNU was found, and a threshold dose suitable for use in multistage carcinogenesis experiments was derived from these data. For any given total dose of MNU, the tumour incidence was greater if the MNU had been administered in several small fractions than if it had been administered in fewer larger ones. Extending the interval between doses did not reduce the tumour incidence. It is argued that these results support the multistage theory of carcinogenesis. The histopathology and cell-surface alterations which characterize the development of MNU-induced bladder cancer are described and the contribution of hyperplasia and calculi are discussed.

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Section: Electron Microscopymentioning

confidence: 99%

Induction of bladder cancer in rats by fractionated intravesicular doses of N-methyl-N-nitrosourea

Severs¹,

Barnes²,

Wright³

et al. 1982

Br J Cancer

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“…Its possible origin is the reaction of 6a with methyl isocyanate, 10 which is formed in the samples of Nnitroso-N-methyl urea upon storage (Scheme 4). 11 Regioselectivity was also observed in the interaction of 5 with N-oxide of nitrile 7 generated in situ from ethyl chlorooximidoacetate in the presence of Et 3 N 12 that produced a disubstituted isoxazole 8.…”

Section: Methodsmentioning

confidence: 90%

New approach to synthesis of nitronyl and imino nitroxides based on SNH methodology

Tretyakov¹,

Utepova²,

Вараксин³

et al. 2011

Arkivoc

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Dedicated to Professor Usein M. Dzhemilev on the occasion of his 65 th birthday AbstractIt is shown that S N H approach opens new possibilities in the synthesis of polyfunctional nitronyl and imino nitroxides. It is found that the interaction of 4,4,5,5-tetramethyl-4,5-dihydro-1H-imidazol-3-oxide-1-oxyl lithium salt Li1 with 3,6-diaryl-1,2,4-triazines leads to formation of the corresponding triazines bearing nitronyl nitroxide or imino nitroxide substituent at position 5 of the heterocycle. The reaction of Li1 with pyridazine-N-oxide gives rise to nitroxide with buten-3-ynyl substituent 5. Spin-labeled 5 could be readily transformed by the use of 1,3-dipolar and nucleophilic addition reactions, as well as oxidative coupling, that gives a large group of new paramagnets: 2-(1H-pyrazol-5-yl)vinyl-, 2-ethynylcyclopropyl-, 2-(3-(ethoxycarbonyl) isoxazol-5-yl)vinyl-, 1-(pyrrolidin-1-yl)but-3-ynyl-substituted nitronyl nitroxide and a diradical -2,2′-

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“…Chemicals MNU was synthesized by Dr A.K. Wallis in the Courtauld Institute of Biochemistry, Middlesex Hospital Medical School, by the method of Werner (1919). Its purity was checked by melting-point determination and high pressure liquid chromatography as detailed previously (Severs et al, 1982).…”

Section: Methodsmentioning

confidence: 99%

The “promoting” activity of methyl methanesulphonate in rat bladder carcinogenesis

Tudor¹,

Severs²,

Hicks³

1984

Br J Cancer

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Summary The carcinogenic activity of the alkylating agent methyl methanesulphonate (MMS) was investigated in the F344 rat bladder, both untreated and pretreated with a single threshold dose of N-methyl-N-nitrosourea (MNU). On its own, 6 doses of 2.5mg MMS produced a 7% incidence of bladder cancer. After a single intravesical instillation of MNU, the same MMS treatment produced a bladder cancer incidence of 56%. This was significantly higher than the incidence (24%) observed after treatment with MNU alone, and greater than the sum of the lesions produced by either treatment alone. By reference to the mouse skin multistage carcinogenesis model, it is argued that MMS is a complete, albeit weak carcinogen with little initiating but powerful late-stage activity. Its promoting activity is most probably attributable to its potent mitogenic action and in this model it is analogous to a stage 2, rather than a stage 1 skin promoter.

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XCIV.—The constitution of carbamides. Part IX. The interaction of nitrous acid and mono-substituted ureas. The preparation of diazomethane, diazoethane, diazo-n-butane, and diazoisopentane from the respective nitrosoureas

Cited by 66 publications

References 0 publications

Induction of bladder cancer in rats by fractionated intravesicular doses of N-methyl-N-nitrosourea

Induction of bladder cancer in rats by fractionated intravesicular doses of N-methyl-N-nitrosourea

New approach to synthesis of nitronyl and imino nitroxides based on SNH methodology

The “promoting” activity of methyl methanesulphonate in rat bladder carcinogenesis

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