Search results for "Nitroso"

By-products in the rearrangement of N-methyl-N-phenylnitramine

1998

Abstract N-Methyl-N-phenylnitramine was rearranged in the aqueous dioxane — sulphuric acid mixture to 2-nitro- and 4-nitro-N-methylanilines. The isomer ratio was independent of the acidity within the range of −0.3 > Ho > −2.8. Some by-products were isolated and identified e.g. N-methyl-N-nitrosoaniline, its 2-nitro and 4-nitro derivatives, nitrosobenzene and 4′,4″-bis-(N-methylamino)-3′,3″-dinitrodiphenylmethane. The mechanism of the nitramine rearrangement is discussed.

ChemInform Abstract: New Reactions of 2- and 3-Vinylindoles with Azodienophiles, Diethyl Mesoxalat, and Nitrosobenzene: An Access to Functionalized a…

2010

ChemInform Abstract: First Transformations of Pyrano(3,4-b)indol-3-ones to Salvadoricine and 2,3-Diacylindoles.

2010

The readily available methylated pyrano[3,4-b]indol-3-ones 1a and 1b were hydrolyzed to furnish the 2-acetylindol-3-alkanoic acids 2 and 4. Compound 2 was easily transformed selectively to 2-acetyl-3-methylindole (3, salvadoricine). Substrate 1b reacts with molecular oxygen from the air only in the presence of a catalyst to give 2,3-diacetylindole (5) while 1a reacts with nitrosobenzene via a proposed Diels-Alder step to yield 2-acetylindole-3-carbaldehyde (6). The latter product can also be obtained in low yield from the reaction of 1a with molecular oxygen from the air.

Apaf-1 deficient mouse fibroblasts are resistant to MNNG and MMS-induced apoptotic death without attenuation of Bcl-2 decline.

2005

Abstract Simple alkylating agents induce cell death by activating the apoptotic pathway. In rodent fibroblasts, apoptosis triggered by DNA methylation lesions is executed via the mitochondrial damage pathway. Here, we studied cell death induced by the methylating agents methyl methanesulfonate (MMS) and N-methyl-N′-nitro-N-nitrosoguanidine (MNNG) in mouse fibroblasts wild-type (wt) and deficient for Apaf-1 (apaf-1 knockout cells). Apaf-1 is an essential component of the apoptosome complex that becomes activated upon cytochrome c release from mitochondria. We show that apaf-1 knockout cells are more resistant to the cytotoxic effect (as measured by WST assay) of methylating agents. This is d…

Synthesis of nitric oxide in the dorsal motor nucleus of the vagus mediates the inhibition of gastric acid secretion by central bombesin

1999

1. Central administration of bombesin inhibits gastric acid production independently of the centrally or peripherally-acting stimuli employed. This study evaluates the role and location of the cerebral nitric oxide (NO) implicated in the inhibitory effect of central bombesin on in vivo rat gastric acid secretion, as induced by distension with 15 cm H2O, insulin (0.75 u.i. kg-1 i.p.) TRH (1.2 microg kg-1, i.c.) or pentagastrin (100 microg kg-1, i.p.). 2. The acid-inhibitory effect of i.c. bombesin (40 ng kg-1) was prevented by prior administration of L-NAME (80 microg kg-1) in the dorsal motor nucleus of the vagus (DMN). This dose of L-NAME when administered into the nucleus of the tractus s…

Mouse embryonic stem cells are hypersensitive to apoptosis triggered by the DNA damage O(6)-methylguanine due to high E2F1 regulated mismatch repair.

2007

Exposure of stem cells to genotoxins may lead to embryonic lethality or teratogenic effects. This can be prevented by efficient DNA repair or by eliminating genetically damaged cells. Using undifferentiated mouse embryonic stem (ES) cells as a pluripotent model system, we compared ES cells with differentiated cells, with regard to apoptosis induction by alkylating agents forming the highly mutagenic and killing DNA adduct O(6)-methylguanine. Upon treatment with N-methyl-N'-nitro-N-nitrosoguanidine (MNNG), ES cells undergo apoptosis at much higher frequency than differentiated cells, although they express a high level of the repair protein O(6)-methylguanine-DNA methyltransferase (MGMT). Apo…

Soil mutagens are airborne mutagens: variation of mutagenic activities induced in Salmonella typhimurium TA 98 and TA 100 by organic extracts of agri…

2000

As our hypothesis was that soil mutagens are airborne mutagens, possibly modified by soil microorganisms, we checked solvent extracts from agricultural and forest soils collected during late summer in the environment of Mainz, a region highly charged by anthropogenic air pollution, or near Bayreuth, a rural low charged region of Germany, or in a remote region of western Corsica without anthropogenic air pollution for the presence of mutagenicity in Salmonella typhimurium. Levels of mutagenic activities were quantified by calculation of revertants/g from the initial slope of dose-response curves applying tester strains S. typhimurium TA 98 and TA 100 in the absence and presence of an activat…

Short-term effect of ammonia concentration and salinity on activity of ammonia oxidizing bacteria.

2010

A continuously aerated SHARON (single reactor high activity ammonia removal over nitrite) system has been operated to achieve partial nitritation. Two sets of batch experiments were carried out to study the effect of ammonia concentration and salinity on the activity of ammonia-oxidizing bacteria (AOB). Activity of AOB raised as free ammonia concentration was increased reaching its maximum value at 4.5 mg NH 3 -N l −1 . The half saturation constant for free ammonia was determined (K NH 3 = 0.32 mg NH 3 -N l −1 ). Activity decreased at TAN (total ammonium–nitrogen) concentration over 2,000 mg NH 4 -N l −1 . No free ammonia inhibition was detected. The effect of salinity was studied by adding…

Evaluation of the SOS/umu-test post-treatment assay for the detection of genotoxic activities of pure compounds and complex environmental mixtures.

2000

This study presents an evaluation of the SOS/umu-test after introducing an additional dilution and incubation in the post-treatment assay. This treatment reduces the influence of coloured test compounds that otherwise affect the colorimetric determination of the beta-galactosidase activity and the bacterial growth measurement during the testing of complex environmental samples. The post-treatment assay significantly increased the beta-galactosidase activity and consequently the enzyme induction ratios at higher doses of model genotoxins 4-nitroquinoline-N-oxide, N-methyl-N'-nitro-N-nitrosoguanidine, 2-aminoanthracene, benzo(a)pyrene with low or no effect on the sensitivity of the test itsel…

CCDC 160804: Experimental Crystal Structure Determination

2001

Related Article: E.Aiello, S.Aiello, F.Mingoia, A.Bacchi, G.Pelizzi, C.Musiu, M.G.Setzu, A.Pani, P.La Colla, M.E.Marongiu|2000|Bioorg.Med.Chem.|8|2719|doi:10.1016/S0968-0896(00)00211-X