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.     

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.     

Triterpene Glycosides of Astragalus and Their Genins. LXI. Occurrence of Cycloartane 6-O-Monodesmosides

Cyclosiversigenin 6-O--L-rhamnopyranoside and 6-O--D-glucopyranoside were isolated fromAstragalus coluteocarpusBoiss. (Leguminosae) andAstragalus dissectusB. Fedtsch. et N. Ivanova, respectively. Cyclosiversigenin 5-O--L-rhamnopyranoside was shown to be an artifact forAstragalus coluteocarpus.Thus, the cyclosiversigenin 6-O--D-glucopyranoside that was isolated from certainAstragalusspecies is hypothesized also to be an artifact. Glycosylation of the 6 -hydroxyl group of cycloartanes by D-glucose and D-xylose, in contrast with other substituents, does not change the low-field position of the PMR signal of the 4-CH ₃ group (1.65 2.01 ppm) that is caused by the influence of deuteropyridine directly on the 6 -hydroxyl. Obviously one of the hydroxyls of the -D-glucopyranoside or -D-xylopyranoside residues has the same effect in this instance.     

Synthesis of (α-substituted α-aminophosphinic and α-aminophosphonic acids

The reaction of ketoximes with hypophosphorous acid resulted in previously unknown -substituted--aminophosphinic acids, which were oxidized into the corresponding -substituted--aminophosphonic acids.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 2729–2732, November, 1996.     

Ring opening of fluoroalkyl-containing α,β-epoxyketones by aromatic amines

Aromatic amines cause ,-epoxyketones containing a -fluoroalkyl group to undergo ring opening at the -position to give -amino--hydroxyketones.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 882–883, May, 1994.     

Circular Dichroism Spectra of 5- and 7-Bromo-6-ketosteroids

Circulardichroismspectra of 5- and 7-bromo-6-ketosteroidsof the cholestane and stigmastane serieswere studied. A negative Cotton effect corresponding to the n-* -transition of the ketone was observed in the CD spectra of 5-bromo-6-ketosteroids at 300 nm. The analogous Cotton effect was positive in CD spectra of 7-bromo-6-ketosteroids.     

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.     

Synthesis and X-Ray Crystal Structure Study of ]2-Methyl-4-(2-methylbenzoyl)-phenoxy] Acetic Acid Hydrazide

Benzophenone analog 3 has been synthesized and characterized by the X-ray diffraction (XRD) method. The compound crystallizes in a monoclinic space group P2₁/c with cell parameters a = 7.701(8) Å, b = 7.151(5) Å, c= 28.323(3) Å, = 104.639(4)°, Z = 4. The structure exhibits intra- and intermolecular hydrogen bonding of the type N–HO, C–HO, and N–HN. The molecules are interlinked through hydrogen bonds forming an infinite chain. This polymeric-like structure may play an important role in biological activity.     

1H-NMR Investigation of the Binding of 2-Methylnaphthalene to α-Cyclodextrin in D2O Solutions

As -cyclodextrin (-CD) was added to D₂Osolutions of 2-methylnaphthalene, its proton signals shifted to lower fieldsat low concentrations of -CD. At 2.0 × 10^-2 moldm^-3 of -CD, however, a reverse, higher-field shift wasobserved for the H-8 signal, indicating the formation of 1 : 1 and 2 : 1-CD–2-methylnaphthalene inclusion complexes. Intrinsic chemicalshift differences of all the protons in 2-methylnaphthalene have beenevaluated for both the 1 : 1 and the 2 : 1-CD–2-methylnaphthalene inclusion complexes. These intrinsicchemical shift differences suggest that the first -CD molecule has noselectivity in accommodating one end of uncomplexed 2-methylnaphthalene;-CD binds to a methyl group, as well as a naphthalene ring-end havingno methyl group, to form the 1 : 1 inclusion complex, resulting in theformation of two kinds of 1 : 1 complexes.     

Comparison of the X-ray structure of baboon α-lactalbumin and the tertiary predicted computer models of human α-lactalbumin

Summary The previously predicted structures of human -lactalbumin by homology with hen egg white lysozyme by an automatic method, after the alignment stage, are compared to the X-ray determined structure of baboon -lactalbumin. The root mean square by rotation method (RMSR) deviations for 122 C- atoms between the two models and the X-ray structure are 2.0 Å and 2.3 Å. The RMSR deviations for all atoms, except for differences in human and baboon sequences, are 2.8 Å and 3.1 Å. If the flexible C-terminus (residues 112–122) are removed then these RMSR deviations are reduced to 2.4 Å and 2.3 Å respectively. These results are consistent with the fact that the RMSR deviation between the human and baboon X-ray structures increases from residue 112 onwards and is conformationally flexible.     

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.     

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).

     

Bromination of polyfluorinated α,β-enones

Polyfluoroalkyl-,-enones readily add Br₂ to give ,ß-dibromoketones. The latter are readily and regioselectively dehydrobrominated to -bromo-,-enones on treatment with K₂CO₃ or NEt₃ Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 12, pp. 2134–2136, December, 1993.     

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     

Determination of Stability Constants for Alkanol/α-Cyclodextrin Inclusion Complexes using the Surface Tension Method

The stability constants for the inclusion of alkanols with-cyclodextrin (-CD) in aqueous solutionhave been determined using the surface tension method. Dataanalyses assuming 1 : 1 stoichiometry were appliedto estimate the stability constants of thesecomplexes. The stability constants obtained using this methodwere in reasonable agreement with the corresponding values inthe literature. Chemically modified -CDs could not beused in this method because those CDs themselves have surfaceactivity. In addition, the relation between the stability constantsand the carbon number of alkanols is discussed.     

The structure of 16, 17β-epoxy-17α-pregn-5-en-3β-ol-20-one monohydrate

The structure of the title compound (1) has been studied by means of X-ray diffraction. The region of cycleD in epoxide1 was compared with that of the 16,17-epoxy derivatives of progesterone and pregnenolone (studied previously) as well as with that of the respective 16,17- and 16,17-cyclopropano analogs. In contrast to the 16,17-epoxy-20-oxo derivatives, in compound1 the electron conjugation of the epoxide ring with the CH₃CO group at C(17) is partly disrupted. Moreover, the steric congestion at C(17) is significantly less pronounced in 16,17-epoxide1 than in its 16,17-counterpart. Both of these factors, especially steric decongestion, are favorable for nucleophilic attack at C(17) in the molecule of1. The X-ray diffraction data do not contradict the previously advanced mechanism of epoxide ring opening in 16,17- and 16,17-epoxy-20-oxo steroids by nucleophilic reagents.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 401–405, February, 1993.     

A spectrophotometric determination of the formation constants of the inclusion complexes ofα- andβ-cyclodextrins with the azonium and ammonium tautomers of methyl orange and methyl yellow

The color fading caused by the addition of-cyclodextrin or-cyclodextrin to an aqueous solution of a tautomeric mixture of methyl orange or methyl yellow is studied spectrophotometrically at pH 1.1 and 25.0°C. A model involving 1 : 1 stoichiometry has been used to analyze the spectrophotometric data. The addition of a cyclodextrin shifts the tautomeric mixture towards the side of the ammonium tautomer. An expression allowing the calculation of the tautomeric equilibrium constant of the inclusion complexes is derived. The formation constants of the inclusion complexes of the individual tautomers are determined. Both- and-cyclodextrins bind the ammonium tautomer stronger than the azonium tautomer. The inclusion complexes of-cyclodextrin are more stable than the corresponding ones of-cyclodextrin.     

α-Alkoxy-β-dicarbonylverbindungen durch Acylierung von Lithiumenolaten

A series of -alkoxy--dicarbonyl compounds2 were prepared by acylation of lithium enolates in good to excellent yields by a simple one-pot procedure.

     

Certain Transformations of Anabasine and Nicotine

Electrocatalytic reduction of the alkaloids anabasine and nicotine was investigated. 1-,-Dipiperidyl and hexahydronicotine were prepared. The reactions of anabasine and the hydrogenated alkaloids with dicarboxylic acid anhydrides were studied.     

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.