Synthesis and some reactions of α-silaacetylenic ketones of the thiophene series

The oxidation of secondary silaacetylenic alcohols of the thiophene series with active manganese dioxide in ethereal solution has given the corresponding ketones.Translated from Khimiya Geterotsiklicheskikh Soedinenii, Vol. 6, No. 7, pp. 891–893, July, 1970.     

Proton magnetic resonance spectra of some silyl-substituted ethylenes

Conclusions The PMR spectra of a number of silyl-substituted ethylenes were obtained. An explanation was given for the positions of the resonance lines of the olefinic protons.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 4, pp. 875–876, April, 1971.     

Synthesis of Imidazolium and Benzimidazolium Triiodides

Russian Journal of Organic Chemistry - 1,3-(Di)acetonylimidazolium and -benzimidazolium triiodides were synthesized in a one-pot fashion by reactions of imidazole, 3-(1H-imidazol-4-yl)prop-2-enoic...     

New Organosilicon Bis-Derivatives of 2-Thiobenzimidazole

Russian Journal of General Chemistry - The earlier unknown organosilicon polyiodides of 2-thiobenzimidazolium have been synthesized basing on the three-component reaction of 2-thiobenzimidazole,...     

Reaction of Imidazoles and Triazoles with 1-(Benzotriazol-1-yl)-2-iodoethanone

Reactions of 2-methyl-1H-imidazole, 1H-benzimidazole, 4H-1,2,4-triazole, and 1H-benzotriazole with 1-(1H-benzotriazol-1-yl)-2-iodoethan-1-one in the absence of a base gave the corresponding N-mono- and N,N′-disubstituted derivatives. 4H-1,2,4-Triazole-3-thiol reacted with 1-(1H-benzotriazol-1-yl)-2-iodoethan-1- one to afford 1-([1,3]thiazolo[2,3-c][1,2,4]triazol-5-yl)-1H-benzotriazolium triiodide.     

Alkylation of 2-Sulfanylbenzoxazole with α-Iodoketones in the Absence of Bases

Reaction of 2-sulfanylbenzoxazole with 1-iodopropan-2-one, 2-iodo-1-phenylethanone, and 2-iodo-1-(thiophen-2-yl)ethanone without solvent and bases afforded bis(benzoxazol-2-yl)disulfonium derivatives in a single preparative stage. The reaction proceeds as a domino-process and includes the alkylation of a sulfanyl group of benzoxazole, the reduction of iodoketone with hydrogen iodide, the oxidation of 2-sulfanylbenzoxazole to disulfide, the alkylation of disulfide atoms of sulfur, and the formation of triiodideanions. The yield of disulfonium derivatives increases twice in the presence of equimolar amount of iodine.     

Topical treatment with OGG1 enzyme affects UVB-induced skin carcinogenesis

Nonmelanoma skin cancer resulting from UVB exposure is a large and growing problem in the United States. Production of reactive oxygen species (ROS) during the UVB-induced inflammatory response results in the formation of oxidative DNA adducts such as 8-hydroxy-2-deoxyguanine (8-oxo-dG), which have been shown to contribute to the development of this cancer. The 8-oxoguanine DNA glycosylase (OGG1) enzyme repairs 8-oxo-dG adducts, suggesting that enhancing its activity in the skin might increase 8-oxo-dG repair thus preventing skin cancer development. We therefore used the SKH-1 murine model to examine the effect of topically applied OGG1 on UVB-induced skin cancer development. Mice were exposed three times weekly to UVB followed immediately by topical treatment with a formulation of liposome-encapsulated OGG1 enzyme for 25 weeks. While this treatment did not affect UVB-induced tumor multiplicity, it did reduce tumor size and dramatically reduced tumor progression, as indicated by tumor grade. These results suggest that oxidative DNA damage contributes to the progression of UVB-induced skin tumors and that a topical formulation containing OGG1, perhaps in conjunction with other DNA repair enzymes such as T4 endonuclease V, could be used in populations at high risk for skin cancer development.     

UV-induced degradation of collagen I is mediated by soluble factors released from keratinocytes

Photoaging is a complex condition but its hallmark is the destruction of dermal collagen. This has been attributed to the direct activation of fibroblast matrix metalloproteinases by solar UV. However, we report here that unirradiated fibroblasts increase metalloproteinase production and digest collagen when exposed to cell culture media from irradiated keratinocytes. Enhanced DNA repair in the keratinocytes ameliorates this response. This suggests that soluble factors induced by DNA damage in UV-exposed epidermal keratinocytes signal collagen degradation by fibroblasts in the dermis. This motif of DNA damage in keratinocytes producing effects on other cell types mediated by soluble factors was first identified by Kripke and colleagues in studying UV-induced immune suppression.     

Three branch polyunsaturated organosilicon and organogermanium dendrimers

3-Branch dendrimers of the first generation possessing at the focal point, the silicon atom, a trimethylsilylvinyl or trimethylsilylethynyl group, and at the central germanium atom an isopropyl group have been synthesized using a combined approach or a convergent reaction scheme. NMR spectra of all synthesized compounds are studied, and their molecular masses are calculated and experimentally determined. The key parameters of new dendrimers are given.     

Reaction of organomagnesium derivatives of dimethyldiethynylsilane and methyltriethynylsilane with alkyl(alkoxy)chlorosilanes

Conclusions The reaction of the magnesium bromide derivatives of dimethyldiethynylsilane and methyltriethynylsilane with alkyl(alkoxy)chlorosilanes gave mono- and disubstitution products containing two or three triple bonds.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 7, pp. 1674–1676, July, 1985.