Caesium as counter-ion in the anionic polymerization of ethylene oxide—II: Kinetics in hmpt

Results are reported for the kinetics of the anionic polymerization of ethylene oxide in hexamethylphosphoramide using the caesium alkoxide of the monoethylether of diethylene glycol as initiator at 40·0°.The reactions were found to be first order in monomer and 0·5 in initiator; rates are depressed by adding caesium tetraphenyl boride. These results indicate that propagation takes place by free ions and ion pairs; the respective propagation rate constants are k_(?) = 22 and k_(±) = 0·2 M 'sec.     

Zur Thermodynamischen Begründung der Kovats'schen Retentionsindizes

Chromatographia - Ausgehend von den thermodynamischen Grundlagen wird die Siedepunktsabhängigkeit der Retentionszeiten diskutiert. Über eine Formel vonKlages, nach der sich das Quadrat...     

Gas-chromatographische Trennung isomerer aromatischer C6-C10-Kohlenwasserstoffe

Separation of isomeric aromatic hydrocarbons from each other has been obtained using packed columns and Bentone 34 modified with silicone oil and lanolin. For maximum resolution the proportions of the modifying agents are very important. Retention data and chromatograms of two different column types are given (column 1∶6% Bentone 34; 2,5% lanolin; 1,5% silicone oil. Column 2∶10% silicone oil; 5% bentone 34; 4% lanolin)     

Reactions of SH-Substituted Purine Bases with Glycidol

The regioselectivity of S-alkylation of SH-substituted purine bases with glycidol tends to grow with decreasing temperature. A procedure was developed for epoxidation of these compounds in wet liquid ammonia. The products were tested for immunostimulating activity.     

Reactions of benzothiazole-2-thione and benzothiazole-2-one with acetylene

Reaction of benzothiazole-2-thione and benzothiazole-2-one with acetylene in the presence of potassium hydroxide or cadmium acetate gives 2-vinylthiobenzothiazole and 3-vinylbenzothiazol-2-one, respectively. Benzothiazole-2-thione is partially convened to benzothiazol-2-one by the action of Cd(OAc)₂. Under vinylation conditions the latter also forms 2-vinylthioaniline.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 270–271, February, 1991.     

Stereoselective hydroboration of 5-dimethylaminomethyl-2-methyl-4,5-dihydrofuran: A simple way to (±)-muscarine

Conclusions A fundamentally new scheme was found for the synthesis of (±)-muscarine, in which the required arrangement of all the substituents is achieved in a single step, involving the hydroboration of 5-dimethylaminomethyl-2-methyl-4,5-dihydrofuran.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 6, pp. 1383–1386, June, 1989.