Bromination and iodination of trialkylethynylsilanes

Conclusions The addition of bromine and iodine to trimethyl- and dimethylethylethynylsilanes has been studied. The halogenation of these compounds takes place stepwise. The first molecule of bromine adds at 30–50° and the second at 70–90°. In the case of bromination under UV irradiation, hydrogen bromide is eliminated as a side-reaction. The addition of iodine ceases at the stage of the formation of the diiodovinylsilanes.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 3, pp. 693–694, March, 1967.     

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.     

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.     

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.     

Stereoselective Addition of Dimethyl Diselenide to Trimethylethynylsilane

Russian Journal of General Chemistry -