Kinetics of oxidation of β-picoline to nicotinic acid over vanadia-titania catalyst. 4. Kinetic model

A kinetic model for the β-picoline oxidation over vanadia-titania catalyst is presented. The model covers the reaction mechanism, temperature dependences and a system of kinetic equations. The activation energies and constants in these equations are calculated.     

Synthesis of azo derivatives of 4-aminosalicylic acid

For searching a better 4-aminosalicylic acid derivative with higher activity and less side effects against the inflammatory bowel disease, 4-aminosalicylic acid (4-ASA) was protected by benzyloxycarbonyl and acetyl, respectively. The resultant was hydrogenized to remove protective group of amino group, then the product was reacted with NaNO2 to give diazonium salt, which was conjugated with salicylic acid, hydroxybenzene, TV-salicyloyl glycine acid to get azo derivatives of 4-ASA. The azo derivatives were hydrolyzed under the alkaline condition to get the target products. All compounds were characterized by FT-IR, 1H NMR, 13C NMR spectra in details. New derivatives of 4-ASA were characterized. The synthetic route was reasonable and feasible.     

“Remote” dianions-I. Utility of 4-phenylsulfonylbutanoic acid in the mild conversion of aldehydes and ketones to lactones.

Ketones and aldehydes are converted to lactones in high yield by stepwise treatment with the dianion of 4-phenylsulfonylbutanoic acid and trifluoroacetic anhydride.     

Electrochemical polymerization of dicarboxylic acids—IV. Polymerization of sebacic acid

The electrolysis of sebacic acid was investigated in methanol, methanol:pyridine (1:1) and methanol:acetonitrile (1:1). The various products were analyzed. In methanol, the major product was the oligomeric carboxylic acid fraction (55%) and the yield of oligomeric hydrocarbons and polymer was lower. With the other two solvents, the polymer was the major product. Four types of hydrocarbons were formed: n-alkane, 1-alkene, x-alkene (the position of the double bond is not known) and cycloalkane. The polymers obtained in all the solvents had the character of cross-linked and branched polyethylene, having ester and methoxy groups. These polymers did not suffer degradation during basic hydrolysis. In comparison with adipic acid, sebacic acid had more tendency to yield polymer and carboxylic acids than hydrocarbons.     

Structural variations of N-acetylneuraminic acid,part 19: Synthesis of both epimeric pairs of the 4-C-methyl- and 4-deoxy-4-C-methyl- as well as of the β-methylketoside of 4-deoxy-4-C-methylene-N-acetylneuraminic acid

Summary While the reaction of the 4-oxo-Neu 5 Ac derivative2 a with tributoxy methyl zirconate led exclusively to equatorial 4-C-methyl derivative3 a, the analogous reaction with tetramethyl zirconate yielded a 3:2 mixture of both diastereoisomeres3 a and4 a. After removal of protecting groups the 5-acetamido-3,4-dideoxy-4-C-methyl-D-glycero-D-galacto-2-nonulosonic acid5 a and 5-acetamido-3,4-dideoxy-4-C-methyl-D-glycero-D-talo-2-nonulosonic acid6 a were obtained. The 4-C-methylene derivative was prepared by treatment of the same 4-oxo-derivative with CH₂I₂/Zn/Cp ₂ZrCl₂. Subsequent hydrogenation led to both epimeric 4-deoxy-4-C-methyl derivatives8 a and9 a. Final removal of protecting groups gave the 5-acetamido-3,4,5-trideoxy-4-C-methyl-D-glycero-D-galacto-2-nonulosonic acid10 a respectively the 5-acetamido-2,7-anhydro-4-C-methyl-3,4,5-trideoxy-D-glycero-D-talo-2-nonulosonic acid11 a. The -methylketosides of the 4-deoxy-4-C-methyl- (16) and 4-C-methylene-Neu 5 Ac (15) were prepared via the peracetylated derivatives to obtain modell substrates for enzymatic studies. Thus all free acids were tested for inhibition of CMP-sialate synthease. Only the 4-C-methylene compound15 showed most unexpectedly a strong competitive inhibition of this enzyme.

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Strukturelle Abwandlungen an N-Acetylneuraminsäure, 19. Mitt.: Synthese der beiden Epimerenpaare der 4-C-Methyl- und 4-Deoxy-4-C-methyl- sowie des -Methylketosids der 4-Deoxy-4-C-methylen-N-acetylneuraminsäure. Verhalten gegenüber CMP-Sialat-Synthase

Zusammenfassung Während die Umsetzung des 4-Oxoderivates2 a mit (BuO)₃ MeZr ausschließlich zur equatorialen 4-C-Methylverbindung3 a führt, wurde bei der Reaktion mitMe ₄Zr ein 3:2-Gemisch der beiden Diastereomeren3 a und4 a erhalten. Das 4-C-Methylenderivat7 a wurde durch Reaktion derselben 4-Oxoverbindung mit CH₂I₂/Zn/Cp ₂ZrCl₂ erhalten. Eine anschließende Hydrierung (H₂-Pd/C) führte zu einem trennbaren Germisch der beiden 4-Deoxy-4-C-methylderivative8 a und9 a. Diese Verbindungen konnten durch das Entfernen der Schutzgruppen einerseits in die 5-Acetamido-3,4,5-trideoxy-4-C-methyl-D-glycero-D-galacto-2-nonulosonsäure10 a und 5-Acetamido-2,7-anhydro-4-C-methyl-3,4,5-tridoxy-D-glycero-D-talo-2-nonulosonsäure11 a umgewandelt werden. Die Verbindungen Methyl-5-acetamido-4-C-methylen-3,4,5-trideoxy--D-manno-2-nonulopyranosidonat (15) und Methyl-5-acetemido-4-C-methyl-3,4,5-tridoxy--D-glycero-D-talo-2-nonulopyranosidonat (16) wurden als Modellverbindungen für enzymatische Untersuchungen über peracetylierte Zwischenstufen hergestellt. Überraschenderweise zeigte nur die 4-C-Methylenverbindung15 eine starke kompetitive Hemmung gegenüber CMP-Sialat-Synthase.

     

An X-ray study of a 12-crown-4 host-guest complex. Crystal structure of the 4∶6 complex between 12-crown-4 and aminosulfuric acid

The title compound was prepared by treating a methanolic solution of 12-crown-4 with an aqueous solution of aminosulfuric acid. The crystal for X-ray analysis was obtained by recrystallization from acetone. The compound [(12-crown-4)₄·[NH₃SO₃)₆] (1) is monoclinic, space groupP2₁/a,a=21.900(8),b=15.499(5),c=18.079(5) Å, =67.85(2)°. Refinement led to a final conventionalR value of 0.0788 for 3280 reflections. Supplementary Data relating to this publication have been deposited with British Library as Supplementary Publication No. 82160 (22 pages) and include: the list ofF _obs,F _calc; tables of bond distances, bond angles and selected least square planes, as well as a figure of 12-crown-4 in C₄-conformation.     

Reductive cleavage of highly substituted Δ2-isoxazolines. Synthesis of crispatic acid

The preparation of highly substituted β-hydroxy carbonyl compounds from isoxazolines is featured in a synthesis of crispatic acid. A β-hydroxy imine, the proposed intermediate in this transformation, is isolated for the first time and a stereoselective hydroboration of a 5-vinyl substituted isoxazoline is also reported.     

Stereoselective alkylation of chiral glycine enolate synthons. The enantioselective synthesis of α-amino acid derivatives.

The highly stereoselective alkylation (% de=99.6 to 97.6) of a new chiral glycine enolate synthon derived from D-2-phenylglycinol is described. Deprotection of the alkylation adducts in a one-pot three-step procedure provides the ethyl ester hydrochloride salts of the corresponding α-amino acids with no attending racemization.     

Synthesis of (±)-4-alkanolides from pent-4-enoic acid

Synthesis of (±)-4-hexanolide, (±)-4-nonanolide, and (±)-4-dodecanolide, racemic forms of the insect signal substances, has been accomplished by cationic cyclization of pent-4-enoic acid and its amide in the key step. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 644–646, March, 2008.     

Acetals of lactams and acid amides. 73. Synthesis and some properties of derivatives of 6-nitro-γ-carboline

We have developed two synthesis routes for 4-amino derivatives of 6-nitro--carbolines: 1) consecutive conversion of 1,2-dimethyl-3-formyl-5-nitroindole to the 3-cyano derivative, condensation of the latter with DMF diethyl acetal, and cyclization of the enamine formed in this case with ammonia and benzylamine; 2) N-oxidation of 9-substituted 6-nitro--carbolines, transformation of N-oxides to the corresponding -carbolin-4-ones, from which the target compounds are obtained through the 4-chloro derivatives.For Communication 72, see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 502–505, April, 1992.     

Esters ofβ -ketophosphonic acids. VII. The products of the reaction ofα-chlorocyclohexanone with the diethyl ester of ethylphosphonous acid and the sodium salt of the monoethyl ester of ethylphosphonous acid

Summary The action of diethyl ethylphosphonite on-chlorocyclohexanone gives cyclohexen-1-yl-1 -ethyl ethylphosphonate, Cyclohenen-1-yl-1-ethyl ethylphosphonate is also obtained by the action of sodium monoethyl ethylphosphonite on a-chlorocyclohexanone.     

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.     

Aerobic oxidative-carbonylation of olefins. A convenient preparation of β-hydroxyalkanoic acid derivatives from olefins

A variety of β-hydroxyalkanoic acid derivatives were prepared by palladium catalyzed aerobic oxidative-carbonylations of terminal olefins at normal pressure of carbon monoxide and oxygen mixed gas.     

Unsaturated polyesters—IV. Kinetics of polyesterification of cinnamylsuccinic acid with 1,4-tetramethylene glycol

The polyesterifications of cinnamylsuccinic acid with 1,4-tetramethylene glycol in both equimolar and non-equimolar ratios were investigated over the range of 130–180°C in the absence and the presence of p-toluenesulphonic acid as catalyst. The kinetic equations were: d[COOH]/dt = k₁[COOH][OH]² and d[COOH]/dt = k₂[COOH]² for uncatalyzed and acid-catalyzed polyesterifications, respectively. The apparent rate constants for uncatalyzed and acid-catalyzed reactions were evaluated by using the method of least squares for various values of initial molar ratios between [OH] and [COOH]. The activation parameters were also calculated.     

Brønsted acid catalyzed propargylation of 1,3-dicarbonyl derivatives. Synthesis of tetrasubstituted furans

Simple Br?nsted acids such as p-toluenesulfonic acid monohydrate (PTS) efficiently catalyze a direct substitution of the hydroxyl group in propargylic alcohols with 1,3-dicarbonyl compounds. Selective propargylation or allenylation is obtained depending on the nature of the alkynol. Reactions can be performed in air in undried solvents with water being the only side product of the process. By applying this reaction as the key step, a range of interesting polysubstituted furans can easily be synthesized in a one-pot procedure. [reaction: see text].     

The curious case of 12-hydroxystearic acid — the Dr. Jekyll & Mr. Hyde of molecular gelators

A comprehensive review of the features driving self-assembly of 12-hydroxystearic acid (12-HSA), a low-molecular-weight gelator, and its applications in drug delivery and as other soft innovative materials are presented herein. 12-HSA is obtained via hydrogenation of ricinoleic acid naturally found in high concentrations in castor oil. The ability of 12-HSA to self-assemble is associated with the presence, position, and enantiomeric purity of the hydroxy group along the fatty acid chain. The polarity and position of the hydroxyl group facilitates more interaction possibilities leading to its exceptional self-assembly behavior giving rise to fibers, ribbons, and tubes in a variety of solvents. Upon self-assembly, 12-HSA undergoes crystallization resulting in the formation of high aspect ratio fibrillar structures due to noncovalent, intermolecular interactions forming self-spanning, three-dimensional networks (called self-assembled fibrillar networks) in both aqueous and organic solvents. Herein, emphasis is placed on emerging applications of 12-HSA supramolecular assemblies (i.e. responsive aqueous foams, gelled complex fluids, drug delivery systems, hydrogels, organogels, xerogels, and aerogel). The vast literature is compiled associated with 12-HSA self-assembly exploring supramolecular assemblies based on one ambidextrous gelator capable of assembling in aqueous and nonaqueous solvent.     

Autoassembly of cage structures. 4. Stereochemistry of 2,5-di-tert-butyl-γ-butyrolactone-4-carboxy-s-(α)-phenylethylamide

The diastereoisomeric lactonamides (2a, b), obtained from the dilactone (1) and S-phenylethylamine, have been separated. X-ray crystallography shows that the high-melting isomer (2a) has theR-configuration at the chiral centers C² and C⁴, the enantiomeric conformation of the -lactone ring being of theS-type in thetwist form, intermediate between envelope ² E and semi-chair ₃ ² T. It is shown by molecular mechanics that the minimum steric energy of2a corresponds to a conformation of the heterocycle close to the envelope form₃E. Examination of van der Waals interactions shows that the calculated structure for2a is preferred. The reasons for the nonidentity of the forms of the -lactone ring of2a in the crystal and the free state are discussed. The crystal structure of2a is composed of two geometrically similar independent molecules associated along the axis by weak hydrogen bonds of two types, the energies of which have been estimated from the v_XH values, which are related by the expression v_XH=f(R_X...O), where X=N, O.For previous communication, see [1].N. N. Semenov Institute of Chemical Physics, Russian Academy of Sciences, 117977 Moscow. Translated from Izvestiya Akademii Nauk, Seriya Khimicheskaya, No. 7, pp. 1601–1611, July, 1992.