Inhibition of the radioactive decay of the isomer 119m Sn with the use of Mössbauer backscattering

In research on the production of beams of coherent γ rays (γ-ray lasers), conditions under which a substantial change Δλ/λ=?(0.114 ±0.027) in the radioactive decay constant λ (the isomeric level 89.53 keV ^119m Sn, T _1/2=293 days) can occur have been found experimentally for the first time. This is made possible by coherent Mo ssbauer (23.87 keV) backscattering from a resonant screen located nearby. An interpretation of the effect observed is proposed on the basis of the idea of dynamic synchronization of oscillations between a nuclear level and a standing wave of Mössbauer radiation. Possibilities for further increasing Δλ/λ up to 0.5 are found.     

Influence of the degree of branching of the O-alkyl radical on the anticholinesterase properties of O-alkyl S-n-butyl methylphosphonothioates

Russian Chemical Bulletin -     

O,O-dialkyl-Se-(o-carboran-9-yl)selenophosphates

Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 9, p. 2187, September, 1988.     

Reaction of potassium dialkyl thiophosphates with ethynyl bromides in the presence of cupric chloride

Conclusions The reaction of potassium diethyl thiophosphate with phenylbromoacetylene in the presence of equivalent amounts of cupric chloride gives 0,0-diethyl S-phenylethynyl thiophosphate. The cuprous salt of diethylthiophosphate acid is formed as an intermediate which reacts with the ethynyl bromide.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 2, pp. 467–469, February, 1986.     

Synthesis of 2-butyl-4,9-decadienoic and 2-butyl-4,9-dimethyl-4,9-decadienoic acids,structural analogues of cygerol

2-Butyl-4,9-decadienoic and 2-butyl-4,9-dimethyl-4,9-decadienoic acids, structural isomers of 2-cyclohexylgeranylacetic acid, which is an active component of the wound healing ointment cygerol, have been synthesized. Hydrocarbon chains C₁₀ have been obtained by the one-pot method of formation of long-chain hydrocarbons, namely, by the telomerization reaction of 1,3-dienes with nucleophiles catalyzed by palladium complexes. A heterogeneous palladium-zeolite catalyst has been used for the first time in telomerization of isoprene with piperidine.     

Synthesis of Functionalized Isoquinolone Derivatives via Rh(III)-Catalyzed [4+2]-Annulation of Benzamides with Internal Acetylene-Containing α-CF3-α-Amino Carboxylates

A convenient pathway to a new series of α-CF₃-substituted α-amino acid derivatives bearing pharmacophore isoquinolone core in their backbone has been developed. The method is based on [4+2]-annulation of N-(pivaloyloxy) aryl amides with orthogonally protected internal acetylene-containing α-amino carboxylates under Rh(III)-catalysis. The target annulation products can be easily transformed into valuable isoquinoline derivatives via a successive aromatization/cross-coupling operation.     

About the Mechanism of the Reaction Cuprous Dialkyl Thiophosphates with the Alkynyl Halides

Abstract

Cuprous dialkyl thiophosphates are convenient reagents for the synthesis of the organophosphorus compounds with the α-acetylenic bond in the alkthiolic radical, and for steric hindered S-propargyl thiophosphates. X-ray investigation established that the crystal is constructed of the tetramer molecules Cu₄[(EtO)₂PSO]₄.¹ The tetramer is a tetrahedral claster of Cu atoms coordinated with four three-dentant chelate-bridged diethyl thiophosphate ligands. Firmly coordinated diethyl thiophosphate ligand in the copper complex does not possess nucleophilic properties and does not react with alkyl bromide. EPR spectroscopy established that the ethynylation of cuprous dialkyl thiophosphate by the substituted ethynyl bromides proceeds via the paramagnetic cupric complex formation. The latter, being unstable under usual conditions, decomposes with the formation of substituted S-ethynyl thiophosphates and CuBr.² Sterically hindered halides of the propargyl type are not liable to Sn2 reaction with the potassium salts of dialkyl thiophosphoric acids, but they readily react with the cuprous salts of these acids yielding S-propargyl thiophosphates. This process is a redox one and it proceeds via the paramagnetic cupric complex formation.     

The Active Mixed Anhydrides of Phosphorous Ph-Acids

Abstract

The ³¹P spectra of H₃PO₃ + Ac₂O and PCl₃ + Ac₂O contain signals which were assigned to the following compounds (δ_p, J_pH): H₃PO₃(8,5; 702), AcO(OH)P(O)H (2,2; 739), (AcO)₂P(O)H (-2,7; 763), (AcO)₃P (131,6); PCl₃ (220,7), AcOPCl₂ (194,6), (AcO)₂PCl (167,O), (AcOl₃P (131,5). The active intermediates with -PH(O)Cl groups are formed on treating phosphorous PH-acids with AcCl, and in other reactions¹. These intermediates are added to aldehydes and ketones resulting in compounds (I), (11) and (111). The compounds of type (11) treated with AcOH transform into compounds of different structure, e.g. into (IV) and (V).