Hydrocarbomethoxylation of 1-hexene with formic acid and methanol under conditions of phosphoric acid catalysis

Conclusions When the hydrocarbomethoxylation of 1-hexene with formic acid is run at atmospheric pressure and temperatures close to room temperature, in the presence of conc. H₃PO₄, an increase in the relative amount of the latter, as well as an increase in the reaction temperature in the investigated range, both favor an increase in the yields of the methyl esters of the C₇ acids, in particular, those containing two methyl groups on the quaternary carbon atom in the -position. An increase in the relative amount of formic acid also favors an increase in the amounts of these esters in the obtained mixtures of esters.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 5, pp. 1116–1118, May, 1971.     

Hydrolysis of furan and 5-nitrofuran penicillins by penicillinase Bacillus licheniformis

The enzymatic hydrolysis of various furan and 5-nitrofuran penicillins by penicillinaseBacillus licheniformis 749/c was investigated. The effect of various side-chain structural groupings on the rate of inactivation of these compounds was studied. The introduction of bulky substituents in the ortho or positions to the amide group and lengthening the side chain or increasing its degree of unsaturation sharply decrease the catalytic action of penicillinase and, consequently, the rate of cleavage of the-lactam ring of the antibiotic. The majority of the furan and 5-nitrofuran penicillins surpass benzylpenicillin in resistance to the enzyme but are inferior to methicillin and oxacillin.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 295–298, March, 1971     

Reaction of onium salts with nucleophilic reagents

Russian Chemical Bulletin -     

The ultraviolet spectra of silocyclobutanes

The UV spectra of Si-substituted silocyclobutanes in vacuum were studied. The bathochromic shift of the absorption band, disclosed by comparison with bands of the corresponding acyclic compounds, can be explained by the highly strained state of the four-membered ring. This same principle in disilocyclobutanes leads to the reduction of the barrier effect of the methylene group, disrupting the interaction of the silicon atoms in the unstrained molecule.     

Derivatives of metal carbonyls containing a metal-o-carborane σ-bond

Russian Chemical Bulletin -