Crystal and molecular structures of 2,10-diacetoxy-13-thiabicyclo[7.3.1]-cis-tridec-5-ene and 2,9-dichloro-13-thiabicyclo[8.2.1]-cis-tridec-5-ene sulfoxide

The crystal and molecular structures of 2,10-diacetoxy-13-thiabicyclo[7.3.1]-cis-tridec-5-ene and 2,9-dichloro-13-thiablcyclo[8.2.1]-cis-tridec-5-ene sulfoxide were established. The conformations of the molecules are such that the unshared pairs of electrons of the sulfur atoms are directed to the carboncarbon double bonds of their molecules. It was observed that there are stereochemical conditions for transannular transformations under the influence of polarized molecules and cations.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1628–1632, December, 1977.     

Bradykinin-potentiating peptide from venom of the spider Latrodectus tredecimguttatus

A bradykinin-potentiating peptide has been isolated from the venom of the spiderLatrodectus tredecimguttatus. Its physicochemical properties and amino acid composition have been investigated in detail. It has been shown by biological testing on isolated neck of the rat uterus that the peptide increases the contractile effect of bradykinin in in vitro experiments. The “potentiating unit” is 2 · 10^?3 mg/ml. A 50% increase in the hypotensive effect of bradykinin at a concentration of the bradykinin-potentiating peptide of 15 µg/kg of body weight has been found, the increase in the intensity of the effect being accompanied by a prolongation of its action.     

Kinetics of p-cumylphenol alkylation by isobutylene in the presence of p-toluenesulfonic acid

Kinetics of p-cumylphenol alkylation by isobutylene in the presence of 0.1–2 wt.% p-toluenesulfonic acid has been studied and a reaction scheme is suggested. The rate constants have been determined.

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- 0,1–2 % . -. .

     

Template synthesis in the nickel(II)–thiocarbohydrazide–propanone triple system

The complexing process proceeding in the Ni^II–thiocarbohydrazide (H₂N–H–NC(=S)–NH–NH₂)–propanone triple system in EtOH solution and nickel(II)hexacyanoferrate(II) gelatin-immobilized matrix has been studied. It has been found that in the first case, template synthesis leading, as a minimum, to formation of three coordination compounds of Ni^II with (N,N,S,S)-donor tetradentate ligands having NiL¹, NiL² and NiL³compositions where L¹ is 4,6,6-trimethyl-2,3,7,8-tetraazanonen-3-di(thiohydrazide)-1,9, L² is 4,6,6,12-tetrametyl-1,9-dithio-2,3,7,8,10,11-hexaazatridekadien-3,11-hydrazide-1 and L³ is 2,8,10,10,16-pentamethyl-5,13-dithio-3,4,6,7,11,12,14,15-octaazaheptadekatrien-2,7,15 is observed, whereas in the gelatin-immobilized matrix, a complexing process in the system considered does not occur.     

The alkylation of benzimidazole derivatives with γ-valerolactone

Reaction of 1, 3-dimethylbenzimidazolone and its 5-methyl and 5-chloro derivatives with -valerolactone in presence of anhydrous aluminum chloride gives the corresponding 6-(1-methyl-3-carboxypropyl)-benzimidazolones.     

Electroreduction of benzo-1,2,3-dithiazolium salts and their selenium analogs in nonaqueous solution

The electroreduction of benzo-1,2,3-dithiazolium cations and their selenium analogs in aprotic solvents takes place in two steps. The first step is a reversible, one-electron transfer leading to the formation of stable radicals detected by EPR. As a result of further electroreduction, the radicals obtained combine with six electrons to form the corresponding o-aminothio(seleno)phenols. Analysis of the reduction potentials of the compounds studied shows that the substitution of a selenium atom for a sulfur in these cations, especially in the 2 position of the heterocycle, facilitates their electrochemical reduction. The electrochemical activity and the kinetics of nulceophilic substitution in the cations studied are compared.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 219–222, February, 1985.     

Vinylacetylene chemistry

It is shown that heating vinylacetylenic piperidols I with phosphorus oxychloride in pyridine solution gives dienynes II, the structure of which is determined, in the case of II (R=H), by means of IR spectra and PMR. Hydration of the dienynes II (R=H, Me) in the presence of mercuric sulfate in methanol solution gives -methoxyketones III (R=H, Me). It is also shown that III and aqueous solutions of ammonia or primary amines give the bicyclic piperid-4-ones IV. In the synthesis of IV (R=H, R₁ = i-Pr, Bu) imines V are obtained, which on hydrolysis give piperidones IV (R = H, R₁ = i-Pr, Bu). When the ß-methoxyketone III (R = H) is heated with 5% sulfuric acid in the presence of mercuric sulfate, chroman-4-one is formed.     

Chemische Vitamin D<Subscript>3</Subscript>-Bestimmung in Lebertran

The different aspects of Vitamin D₃ determination and the data reported in the literature are discussed. The spectrophotometric determination of Vitamin D₃ in cod-liver oil is carried out after the alkaline saponification, extraction of unsaponified parts, precipitation of accompanying sterols and the column- and thin-layer chromatographic purification and separation of vitamin D₃ on 40 cm plates from other vitamins. The dyestuff α-naphtholbenzein is suited well as standard substance for the better location and identification of vitamin D₃ zone on the thin-layer plate. The results obtained from the chemical method were checked through the simultaneous biological determination.     

Fragmentation of the unsubstituted carbohydrate units of cardenolide monosides

In the mass spectra of unsubstituted monosides of cardenolide nature are observed the M⁺ peaks, and also, in each case, three characteristic processes of the fragmentation of the carbohydrate unit. The formation of the ions AglOCH=OH⁺ is the most universal property of these compounds. The stability of ions of the type under consideration depends on the nature and position of attachment of the sugar residue and on the number of polar groups in the aglycone. The laws of the fragmentation of the carbohydrate unit are extended to the spectra of glycosides of other classes.Deceased.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodynykh Soedinenii, No. 3, pp. 345–354, 1983.