Unsaturated five-membered selenium–germanium containing heterocycles based on the reactions of selenium di- and tetrahalides with diorganyl diethynyl germanes

Regio- and stereoselective reactions of selenium dihalides with diorganyl diethynyl germanes in CHCl₃ afford in yields from preparative to quantitative the first representatives of a new class of selenium–germanium containing heterocycles - 3,6-dihalogen-4,4-diorganyl-1,4-selenagermafulvenes. The reaction of selenium tetrachloride under the same conditions leads to the first representatives of a new class of selenium–germanium containing cyclopentene heterocycles - 2-dichloromethyl-2,4-dichloro-3,3-diorganyl-1-selena-3-germacyclopentenes-4 as well as to the unknown 3,6,6-trichloro-4,4-dialkyl-1,4-selenagermafulvenes formed as a result of a spontaneous dehydrochlorination of the cyclopentene heterocycles. In a case of SeBr₄ the process of dehydrobromination is dominating. The structures of the heterocycles were proved by multinuclear (¹H, ¹³C, ⁷⁷Se) spectroscopy and mass-spectrometry. In the ¹H NMR spectra of Z-isomers of 1,4-selenagermafulvenes a long-range spin–spin interaction between exo- and endocyclic olefinic protons through five bonds is revealed lacking in the E-isomers.     

Reaction of methylmagnesium iodide with perfluorocarboxylate esters

Conclusions In the reaction of methylmagnesium iodide with esters of perfluorocarboxylic acids, the magnesium salt of the hemiketal was found to be more stable and the ketone yield was found to be higher with increasing bulk of the alkoxy group of the ester.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 5, pp. 1163–1165, May, 1988.     

Aminomethylation of ethynylsilanes

Conclusions Aminomethylation of mono- and diethynylsilanes has been investigated. Dimethyldiethynylsilane can react at either one or both the ethynyl group positions.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 12, pp. 2818–2820, December, 1969.     

Role of the base and endogenous anions in “ligand-free” catalytic systems for the Suzuki–Miyaura reaction

UV spectroscopic studies combined with kinetic measurements for the Suzuki–Miyaura reaction catalyzed by “ligand-free” catalytic systems have demonstrated that the base is involved in the formation of the palladium complexes ensuring the occurrence of the transmetalation stage. It follows from UV monitoring data for the catalytic reaction involving aryl iodides that a considerable part of palladium during the process is in the form of Pd²⁺ acid complexes with endogenous anions and does not participate in the main catalytic cycle.     

1,1-Diethynylsilacycloalkanes and Propellanes Based Thereon

Previously unknown 1,1-diethylnylsilacycloalkanes (CH₂)4nSi(C& = CH)₂ (n = 3, 4) were prepared by the reaction of HC& = CMgBr with 1,1-dichlorosilacycloalkanes (CH₂)4nSiCl₂ (n = 3, 4). The reaction of (CH₂)₄Si(C& = CMgBr)₂ with (CH2)4SiCl2 in THF under conditions of high dilution gives cyclo(tetramethylene)- silethynes [(CH2)4SiC& = C]4 with an admixture of cyclodi(tetramethylene)silethyne [(CH2)4SiC& = C]2. The re- action of Me2Si(C& = CSiMe2C& = CMgBr)2 with (CH2)4SiCl2 was used to prepare 1,1,4,4,7,7-hexamethyl-10,10- tetramethylene-1,4,4,10-tetrasilacyclododeca-2,5,8,11-tetrayne.     

4-Hydroxy-2-quinolones. 174.* Hydrochlorides of [(alkylamino)alkyl]amides of 1-allyl- 4-hydroxy-6,7-dimethoxy-2-oxo-1,2-dihydro- quinoline-3-carboxylic acid – a new class of opioid receptor antagonists

Hydrochlorides salts of [(alkylamino)alkyl]amides of 1-allyl-4-hydroxy-6,7-dimethoxy-2-oxo-1,2-di-hydroquinoline-3-carboxylic acid were synthesized as potential biologically active compounds. Pharmacological testing showed promise for using these compounds to develop new highly efficient opioid receptor antagonists.     

Acyl iodides in organic synthesis: VII. Reactions with trialkyl(alkynyl)silanes,-germanes, and-stannanes

Reactions of acyl iodides R¹COI (R¹=Me, Ph) with trialkyl(alkynyl)silanes,-germanes, and stannanes (R²C≡CMR ₃ ³ ; M=Si, Ge, Sn) were studied. Acyl iodides reacted with the germanium and tin derivatives with cleavage of the M-C_sp bond and formation of the corresponding trialkyl(iodo)germanes and-stannanes R ₃ ³ MI (M=Ge, Sn) and alkynyl ketones R¹C(O)C≡CR² and R¹C(O)C≡CC(O)R¹. By contrast, the reaction of acetyl iodide with ethynyl(trimethyl)silane gave only a small amount of 1,2-diiodovinyl(trimethyl) silance as a result of iodine addition at the triple bond. Bis(trimethylsilyl)ethyne failed to react with acetyl iodide.