Synthesis of some polycyclic noncondensed pyrimidine structures

Methods for the synthesis of compounds containing two or more pyrimidine rings linked through aliphatic chains with different numbers of carbon atoms are described.Deceased.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 335–340, February, 1995     

Synthesis and study of properties of linear permethylpoly(silane-siloxanes)

Heterofunctional polycondensation of ,-dichloropermethyloligosilanes Cl(Me₂Si) _m Cl (m = 2—6) with 1,5-dihydroxyhexamethyltrisiloxane was used to synthesize linear permethylpoly(silane-siloxanes) with the regular structure —[(SiMe₂) _m O(SiMe₂O)₃] _n —, which are soluble, unlike polydimethylsilane, in common organic solvents. The use of Py instead of Et₃N as an acceptor of HNl results in an increase in the yield, molecular weight, and characteristic viscosity of the copolymers. The molecular weight and viscosity characteristics, oxidative and thermal stabilities, and spectral properties of the synthesized copolymers were studied. The dependence of the oxidative and thermal stabilities of the synthesized copolymers on the number of the SiMe₂ units in the oligosilane fragment of the main chain was established.     

Synthesis and biological activity of yuccagenin bisrhamnoside

The two hydroxyls of yuccagenin can be glycosylated by Koenigs-Knorr condensation with acetobromorhammose in dichloroethane in the presence of mercuric cyanide. The bisrhamnoside of yuccagenin markedly lowers the cholesterol and triglyceride content in blood serum of healthy animals and animals with experimental hyperlipidemia.Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 242–243, May–June, 2000.     

Photochromic dihetarylethenes. 7. Synthesis of bis(thienylazoles), photochromic analogs of diarylethenes

Procedures for the synthesis of 4,5-bis[2,5-dimethyl(3-thienyl)]-1,3-azoles based on 1,2-bis[2,5-dimethyl(3-thienyl)]-2-hydroxyethan-1-one, 2-chloro-1,2-bis[2,5-dimethyl(3-thienyl)]ethan-1-one, and 1,2-bis[2,5-dimethyl(3-thienyl)]ethane-1,2-dione were developed. Dithienylethenic compounds in which the thienyl rings are linked through the azole rings exhibit photochromic properties.     

Triterpene glycosides ofScheffleropsis angkae. I. Structure of glycosides L-B1, L-B2, L-H1, and L-H2

The structures of four triterpene glycosides from the leaves ofScheffleropsis angkae (Araliaceae) are found by chemical methods and NMR spectroscopy to be the 3-O--L-arabinopyranosides of oleanic and ursolic acids and their 28-O--L-rhamnopyranosyl-(14)-O--gentiobiosyl esters, which are designated L-B₁, L-B₂, L-H₁, and L-H₂, respectively. The glycoside L-H₂ is new.Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 136–138, March–April, 2000.     

Synthesis of some phosphonocarbonyl compounds via Horner-Emmons reaction of methylenbisphosphonate

Summary The -carbonyl substituted vinylphosphonates6–9 were synthesized from the -dicarbonyl compounds2–5 and the methylenbisphosphonate1 by a Horner-Emmons reaction in different yields.

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Synthese von Phosphonocarbonylverbindungen durch Horner-Emmons-Reaktion von Methylenbisphosphonsäuretetraethylester

Zusammenfassung Es wurden die -carbonylsubstituierten Vinylphosphonate6–9 mittels Horner-Emmons-Reaktion aus den -Dicarbonylverbindungen2–5 und Methylenbisphosphonat1 in verschiedenen Ausbeuten hergestellt.

     

Electrochemical oxidation of tetramethyl esters of α,α,ω,ω-alcaneteracarboxylic acids

Cyclization of esters of butane-1,1,4,4- and pentane-1,1,5,5-tetracarboxylic acids during electrolysis in methanol in the presence of Nal produces, with a yield of 95%, the esters of cyclobutane-1,1,2,2- and cyclopentane-1,1,2,2-tetracarboxylic acids. Under similar conditions, esters of the highest ,,,-alkanetetracarboxylic acids undergo iodation and hydroxymethylation due to electrical oxidation of methanol to formaldehyde. During electrolysis in methanol in the presence of NaOAc, the esters of ,,,-alkanetetracarboxylic acids undergo effective hydroxymethylation, followed by cyclization into substituted five- and six-member lactones, or tetrahydrofurans when structurally possible.N. D. Zelinskii Institute of Organic Chemistry, Russian Academy of Sciences, 117913 Moscow. Translated from Izvestiya Akademii Nauk, Seriya Khimicheskaya, No. 10, pp. 2332–2339, October, 1992.     

Synthesis ofN-alkylamides of 3-fluoroalkylaziridine-2-carboxylic acids

The N-alkylamides of 3-fluoroalkylaziridine-2-carboxylic acids have been prepared for the first time by the interaction of ethyl 0-fltioroalkyl-,-dibromocarboxylates with primary amines.Prepared by a known procedure;² characteristics of previously unknown ester1b are given in the Experimental section.     

Reaction of Pregnenolone and 3α,5-Cyclo-5α-pregnan-6β-ol-20-one with Trifluoroperacetic Acid

The reaction of pregnenolone and 3,5-cyclo-5-pregnan-6-ol-20-one with trifluoroperacetic acid produces the trifluoroacetates, hydrolysis of which gives the 3,5alpha;,6-triol.     

Intercalation of ferrocene and dimethylaminomethylferrocene into α-Sn(HPO4)2 · H2O and α-VOPO4 · 2H2O

The intercalation of ferrocene and dimethylaminomethylferrocene into -tin(IV) hydrogen phosphate (SnP) and -vanadyl phosphate has been investigated. Successful intercalation of 0.81 mol of dimethylamino-methylferrocene into -SnP by an acid-base reaction in aqueous medium to form a bilayer of protonated amines was achieved. However, ferrocene was not intercalated under the same conditions. Intercalation of -vanadyl phosphate by 0.11 mol of ferrocene in acetonic medium at room temperature was effected by a redox topotactic reaction. The voluminous dimethylaminomethylferrocene was not intercalated into -vanadyl phosphate.     

Synthesis of novel imidazolidinones

Summary The preparation of a number of new imidazolidinones by a simple method based on the reaction of -aminocarboxamides with carbonyl compounds is described.

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Synthese neuer Imidazolidinone

Zusammenfassung Die Darstellung einer Reihe neuer Imidazolidinone durch Reaktion von -Aminocarboxamiden mit Carbonylverbindungen wird beschrieben.

     

One-pot synthesis of 4,6-diaryl-3-cyanopyridine-2(1H)-thiones and their transformation to substituted thieno[2,3-b;4,5-b]dipyridines and pyrido[3",2":4,5]thieno[3,2-d]pyrimidines

4,6-Diaryl-3-cyanopyridine-2(1H)-thiones were synthesized in one step by the reaction of elemental sulfur, malononitrile, and 2-aryl-1-aroylethylenes in the presence of excess triethylamine. The products were used in one-pot syntheses of substituted thieno[2,3-b;4,5-b]dipyridines and pyrido[3",2":4,5]thieno[3,2-d]pyrimidines.     

Complexation of Oleuropein and trans-Cinnamic Acid with Cyclodextrins

The complexation of oleuropein and trans-cinnamic acid with -, -, and -cyclodextrin has been studied in aqueous model systems by light scaterring. The influence of various parameters (pH, concentration, reaction time, nature of cyclodextrin) has been thoroughly examined. The formation of binary (1:1) inclusion complexes and the higher inclusion ability of -CD for both compounds has been indicated. Trans-cinnamic acid was extracted from olive olive oil following its complexation with -CD at satisfactory recovery levels.     

Synthesis of driman-8α,11-diol from sclareol through 8α,12-epoxy-14,15-bisnorlabdan-13-one

A four-step synthesis of driman-8,11-diol from sclareol in 44% total yield is described that includes the intermediates (12R)-8,12-epoxy-14,15-bisnorlabdan-13-one, (12S)-8,12-epoxy-12-acetoxy-13,14,15,16-tetranorlabdane and 8,12-epoxy-13,14,15,16-tetranorlabd-11-ene.Institute of Chemistry, Academy of Sciences of the Republic of Moldova, Kishinev, fax (3732) 73 97 75, Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 124–125, March–April, 2000.     

Die Acetalgruppe, 1. Mitt. Acetale von Halogenmethyl-arylcarbinolen

Several halomethyl-arylcarbinols were prepared, and the influence of substituents on enantiomer selectivity in the acetalisation reaction with [2S-(2,3a,4,7,7a)]-octahydro-7,8,8-trimethyl-4,7-methanobenzofuran-2-ol was examined.

Unserem sehr verehrten Lehrer, Herrn Prof. Dr.Otto Hromatka, mit den besten Wünschen zum 80. Geburtstag gewidmet.     

Hexafluoroacetone as Protecting and Activating Reagent. Glycosylated Malic, Citramalic, and Thiomalic Acid Derivatives, New Glycosylated Building Blocks for Drug Design [1]

Summary. Glycosylated -hydroxy and -mercapto acids have been synthesized starting from malic/citramalic/thiomalic acid and Ac₄--D-Glc-NH₂/Bzl₄--D-Glc-NH₂ using hexafluoroacetone as protecting and activating reagent.Dedicated to Prof. Dr. Horst Wilde on the occasion of his 65^th birthday     

Dichloromethyl tert-butyl ketone in the Darzens reaction

The condensation of dichloromethyl tert-butyl ketone (1) with benzaldehyde, para-bromobenzaldehyde, and 2,4-dichlorobenzaldehyde under conditions for the Darzens reaction gives 1-aryl-1-chloro-4,4-dimethyl-2,3-pentanediones (2–4). In the case of nitrobenzaldehydes, the reaction products are 1-aryl-2-chloro-1,2-epoxy-4,4-dimethylpentanones (5 and 6), which isomerize to -chloroketones (7 and 8) upon prolonged storage or heating at reflux in benzene.A. E. Arbuzov Institute of Organic and Physical Chemistry, Kazan Science Center, Russian Academy of Sciences, 420083 Kazan. Translated from Izvestiya Akademii Nauk, Seriya Khimicheskaya, No. 2, pp. 438–441, February, 1992.     

Effects of α-tocopherol and its acetate on the hydrolytic activity of phospholipase D in egg yolk phosphatidylcholine bilayers

Effects of -tocopherol (Toc) and -tocopherol acetate (TocA) on the hydrolysis activity of phospholipase D (fromStreptomyces chromofuscus) were studied in small unilamellar vesicles (SUV) of egg yolk phosphatidylcholine (PC). Choline produced in the reaction was monitored by use of a choline oxidase — oxygen electrode. Addition of 18 mol% Toc into SUV (2 mM PC) brought about a twofold rate of choline production. On the other hand, the effect of 18 mol% TocA in SUV was very small. The apparent maximum velocity,V _max(app), increased by addition of Toc in SUV. The apparent Michaelis constant,K _m(app), was unchanged by addition of Toc and TocA in SUV. The Toc and TocA molecules did not have significant effects when PC was solubilized in the micelles of heptaethylene glycol dodecyl ether. The effects of Toc and TocA are, therefore, not due to specific ones on the enzyme itself, but rather upon the bilayer-organization of the substrate. Measurements of spreading pressure showed complete miscibility of PC and Toc, and limited mutual solubility of PC and TocA, suggesting stronger attractive interactions between Toc and PC than those between TocA and PC in the bilayers.     

Synthese von α-Methyl-homocysteinthiolacton

Summary A facile high yield large scale methylation procedure affording2c is reported utilizing the N-[bis(methylthio)-methylen-protected derivative4a as an intermediate. The optical resolution of racemic2c is described leading to (S)-2b. In addition the thiolactone2c undergoes oxidative ring opening by bromine to the corresponding sulphonic acid5.

     

Selective reduction of the acyl group in cyclic α-acyl-β-dicarbonyl compounds with sodium cyanoborohydride. Efficient synthesis of cyclic α-alkyl-β-dicarbonyl compounds

Efficient synthesis of cyclic -alkyl--dicarbonyl compounds of the cyclopentane, cyclohexane, tetronic acid, and -pyrone series from the corresponding cyclic -acyl--dicarbonyl compounds under the action of NaBH₃(CN) in a THF--HCl system is described.