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.     

Zur Kenntnis der gemeinsamen Einwirkung von elementarem Selen und gasförmigem Ammoniak bzw. Ethylenimin auf Ketone

Elemental sulfur reacts with ketones and gaseous ammonia at room temperature yielding thiazoline-3 in excellent yields. Under the same conditions elemental selenium does not react at all. Attempts using the known techniques which have been applied in improving the reactivity of slowly reacting ketones in thiazoline-3-synthesis have been unsuccessful (Exp. No. 1–17). The reaction of -halogenketones with sodiumhydrogenselenide to synthesize -hydroselenoketones gives only the original ketones and selenium in almost quantitative yields (No. 18–23). The same is observed with -haloketones and sodium ore magnesium-diselenides (No. 24–45). The explanation of these unexpected results is the strong reducing power of the hydrogenselenide (No. 46–52). Even -bromoketones with activated bromine (i.g. by phenyl groups) were reduced by sodiumhydrogensulfide giving red undefinite oils. However, -chloroketones give -mercaptoketones in excellent yields (No. 53–61). Hydrogenselenide reduces -mercaptoketones to sulfur and ketones in the presence of triethylamine (No. 62–67). Also the transformation of -selenocyanketones to ,-diketodisenides by alkali or the oxidative hydrolysis of selenium-BUNTE salts does not work and gives elementary selenium only. Studies about the concomitant reaction of elementary selenium and ethylenimine on ketones were continued (No. 68–82).

     

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.     

Zur Reaktion von Permethylcyclosilanen mit Halogenen

The series of ,-diiodopermethylpolysilanes, I(SiMe ₂) _n I, (n=4–6) andX(SiMe ₂)₄ X, (X=Cl, Br) has been prepared by the action of halogen on the corresponding cyclic compounds (SiMe ₂) _n . The mass spectra, NMR-, IR- andRaman-spectra of these compounds have been recorded.

Herrn Prof. Dr.Josef Schurz zum 60. Geburtstag gewidmet.     

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.

     

Discrete Variational (DV)-Xα Calculations of Incomplete Cubane-Type Molybdenum Clusters [Mo3X4(H2O)9]4+ (X= O,S)1

Electronic structures of two incomplete cubane-type clusters [Mo₃X₄(H₂O)₉]⁴⁺ (X =O, S) have been calculated by the discrete-variational (DV)-X method. The calculations explain the experimental results of valence-band X-ray photoelectron spectra, electronic spectra, and reactivity difference toward acetylene. The net charge of Mo in [Mo₃S₄(H_2O)₉]⁴⁺(S) is more negative than that of Mo in [MO₃O₄H₂O)⁴⁺] (O), and the bridging sulfur atoms are the main negative charge-source for the molybdenum atoms in the cluster S. As for S,levels of HOMO (45e) and LUMO (46e) consist mainly of Mo 4d and-S 3p atomic orbitals, and contribution of ₃-S 3p to the orbitals is not large. The existence of Mo-Mo, Mo--S, and Mo- ₃-S bounds is clear from the contour maps of the orbitals. As for O levels of HOMO (40e) and LUMO (41c) consist mainly of Mo 4d and-O 2p atomic orbitals. Contribution of ₃-O 2p to the orbitals is not large except in the orbital 30a₁,. The existence of Mo-Mo, Mo--O, and MO- ₃-O bonds also is appreciable from the contour maps of the orbitals.Dedicated to Professor Jiaxi Lu on the occasion of his 80th birthday.     

Interaction of α,β-Unsaturated Ketones of the Adamantane Series with N,N'-Binucleophiles

The influence has been established of the structure of the initial ketone, the reactants, and the reaction conditions on the direction of the interaction of ,-unsaturated ketones of the adamantane series with hydrazine, phenylhydrazine, semicarbazide, thiosemicarbazide, urea, and thiourea. It was found that on interaction with hydrazine and phenylhydrazine both intermediate hydrazones and the final cyclization products, pyrazolines, were formed. Reaction with semicarbazide and thiosemicarbazide leads only to the synthesis of derivatives at the carbonyl group, semicarbazones and thiosemicarbazones, but with urea and thiourea leads to products of addition at the double bond.     

Asymmetric reduction of acetophenone and propiophenone by NaAl(IPTOLate)H2 combined with enantiomeric enrichment of the reaction product as an inclusion complex with IPTOL

An improved procedure was developed for asymmetric reduction of acetophenone and propiophenone by the chiral reagent NaAl(IPTOLate)H₂. This procedure is based on isolation of the chiral alcohol that formed as a crystalline host—guest complex with the IPTOL ligand. The enantiomeric enrichment of the product was as high as 97% ee. The ability of IPTOL and its analogs to form host—guest complexes with a number of ether-type solvents, 1-phenylethanol, and 1-phenylpropan-1-ol as well as thermal stabilities of IPTOL-containing complexes with these alcohols were studied.     

Fluoroaliphatic esters of fluorosulfonic acid. 6. Interaction of fluorine-containing α,β-bis-fluorosulfatocarbonyl compounds with nucleophilic reagents

Fluorine-containing ,-fluorosulfatocarbonyl compounds interact with halides of alkali metals with the formation of -halogeno--dicarbonyl derivatives.A. N. Nesmeyanov Institute of Heteroorganic Compounds, Russian Academy of Sciences, 177813 Moscow. Translated from Izvestiya Akademii Nauk, Seriya Khimicheskaya, No. 3, pp. 715–719, March, 1992.     

Some peculiarities of hydrosilylation of α,ω-divinyloligosilanes

The stability of Si-Si bonds in linear and cyclic permethyloligosilanes and in ,-divinyloligosilanes under conditions of hydrosilylation in the presence of the Speier's catalyst was studied. Polycarbosilanes containing silylene fragments in their backbone chains were prepared by the reaction of 1,4-bis(dimethylsilyl)benzene with ,-divinyloligosilanes. It was found that the structure of these polymers is disturbed due to the side reaction involving the cleavage of the Si-Si bond in vinyloligosilanes under the action of H₂PtCl₆.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 2547–2549, October, 1996.     

Synthesis and thermal decomposition of 3-aroyl-4-aryl-2-pyrazolines

Summary 3-Aroyl-4-aryl-2-pyrazolines (21–40) have been synthesized by the reaction of ,-unsaturated ketones (1–20) with diazomethane. These 2-pyrazolines gave -methyl-,-unsaturated ketones (41–46) on thermal denitrogenation.Dedicated to Prof. Dr.F. Sauter on the occasion of his 65^th birthday     

Substituierte 3-Amino-thiophene und 3-Amino-selenophene aus β-Chlor-α-cyan-zimtsäurenitril

Summary -Chloro--cyano-cinnamonitrile (1) reacts in one step with -oxo-thioles3 or successively with sodium sulphide and -chlorocarbonyl compounds4 to form the 5-substituted 4-amino-2-phenyl-thiophene-3-carbonitriles5. Analogously, the successive reactions of -chloro cinnamonitrile1 with sodium selenide — produced in situ from selene and sodium boronhydride — and -chlorocarbonyl compounds4 yields the 5-substituted 4-amino-2-phenyl-selenophene-3-carbonitriles6.

     

Bilirubin conformational enantiomer selection in sodium deoxycholate chiral micelles

Intramolecularly hydrogen-bonded, bichromophoric tetrapyrrole pigments, bilirubin-IX and mesobilirubin-XIII, adopt either of two enantiomeric conformations which are in dynamic equilibrium in solution. InpH 8 aqueous sodium deoxycholate solutions, chiral micelles preferentially select one conformational enantiomer, and the solutions exhibit a bisignate circular dichroism Cotton effect in the vicinity of the bilirubin long wavelength electronic transition. Exciton coupling theory indicates a predominance of the left-handed (or negative) chirality bilirubin conformational enantiomer.     

Synthesis of o-phenylphenol from cyclohexanone over platinum supported on calcined Mg/Al hydrotalcite

A kinetic model is proposed to account for the effect of oxygen during catalyst premodification on the rate and enantioselectivity in hydrogenation of methyl pyruvate over cinchonidine modified platinum catalysts.This revised version was published online in December 2005 with corrections to the Cover Date.     

Synthesis,crystal structure and conformation of N-acetyl-Cα,α-diethylglycine-N′-methylamide

Summary Synthesis and X-ray structure analysis of N-acetyl-^,-diethylglycine-N-methylamide [CH₃-Co-NH-C(C₂H₅)₂-CO-NHCH₃] are described. The compound was obtained from the corresponding N-acetyl derivative [CH₃-CO-NH-C(C₂H₅)₂-COOH] through the mixed anhydride procedure. It crystallizes as monohydrate (C₉H₁₈N₂O₂·H₂O) in space group P2₁/c,a=7.139(1),b=11.823(2),c=15.778(3) Å, =122.23(1)°,V=1126.53 ų,D _m=1.20 Mgm^–3 (room temperature),R=0.046 for 1523 reflections. The crystal packing is dominated by two strong hydrogen bonds between the water molecule and two carbonyl oxygen atoms and two weak H-bonds to two amide-N-atoms of symmetry-equivalent molecules. The molecular conformation is closer to a 3₁₀-helix then ana-helix.

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Synthese, Kristallstruktur und Konformation von N-Acetyl-^,-diethylglycin-N-methylamid

Zusammenfassung Es wird über Synthese und die röntgenographische Strukturbestimmung von N-Acetyl-^,-diethylglycin-N-methyl-amid [CH₃-CO-NH-C(C₂H₅)₂-CO-NH-CH₃] berichtet. Die Verbindung wurde unter Anwendung der Methode der gemischten Anhydride aus dem entsprechenden N-Acetylderivat [CH₃-CO-NH-C(C₂H₅)₂-COOH] erhalten. Sie kristallisiert als Monohydrat (C₉H₁₈N₂O₂·H₂O) in der Raumgruppe P2₁/c mita=7.139(1),b=11.823(2),c=15.778(3) Å, =122.23(1)°,V=1126.53 ų,D _m=1.20 Mgm^–3,D _x=1.204 Mgm^–3 (Raumtemperatur).R=0.046 für 1523 Reflexe. Die Kristallpackung ist dominiert durch zwei starke H-Brücken vom Wassermolekül zu zwei Carbonylsauerstoffatomen sowie zwei schwachen H-Brücken zu zwei Amid-N-atomen symmetrieequivalenter Moleküle. Die Konformation des Peptidgerüstes ist näher einer 3₁₀ als einera-Helix.

     

Dimethyl dichloromalonate as a new synthetic equivalent of methyl dichloroacetate in the Darzens condensation

Dimethyl dichloromalonate reacts with aldehydes in the presence of sodium methoxide to form-chloropyruvates,-chloroglycidates, or,-dichlorohydrins, depending on the nature of the aldehyde.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1544–1545, August, 1995.     

Membrane transport of dicarboxylic and α-hydroxy carboxylic acids induced by α-amino phosphonates

New -amino phosphonates containing different alkyl and aryl substituents at the -carbon atom were synthesized in high yields by the Kabachnik—Fields and Pudovik reactions. These compounds were studied as carriers of several -hydroxy carboxylic and dicarboxylic acids through liquid impregnated membranes. These -amino phosphonates studied are capable of molecular recognition of oxalic acid among structurally similar -hydroxy carboxylic and dicarboxylic acids. The efficiency and selectivity of mass transfer of oxalic acid increase with an increase in the lipophilicity of the -amino phosphonate.     

Semiempirical calculations on cyclodextrins

In order to obtain information on the different reactivities of the hydroxyl groups of the glucopyranose units or the inclusion complex formation mechanism, the charge distributions and the geometrical constraints must be determined. Geometry optimizations, employing the AM1 semiempirical method, have been performed for -D-glucopyranose, –,–, and -cyclodextrins. The data obtained were compared with X-ray diffraction data of the cyclodextrins.Dedicated to Professor József Szejtli.     

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.     

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.