New method for the synthesis of α-chlorocinnamonitriles

A novel method for the preparation of nitriles of -chlorocinnamic acid from aldehydes and ketones was proposed. Transformation of carbonyl compounds into hydrazones followed by treatment of the reaction mixture with CCl₃CN in the presence of copper chloride(i) yields -chlorocinnamonitriles.     

General method of synthesizing esters of ω-nitropolyenic acids

Summary A general method has been developed for the synthesis of esters of polyenic -nitro acids.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya No. 11, pp. 2093–2095, November, 1964     

New and Stereospecific Synthesis of α-Ethylenic Ketones

Abstract

H. Kise et al¹ have shown that the reaction of β-propiolactones 1 with ylides 2 give phosphonium carboxylate betaïne 3. We now report that, carried out under different conditions, reaction of lactones 1 with the same ylides proceeds through pathway (b). Thermolysis of 4 affords α-ethylenic ketones 5. The mecanism of this new extrusion reaction of triphenylphosphine oxyde probably involves the generation of an oxaphosphene as an intermediate.     

Use of Wittig reaction for synthesizing α,β-unsaturated and polyenoic acids

Summary The reaction of carbethoxymethylenetriphenylphosphorane with various aldehydes is a general method of synthesizing esters of ,-unsaturated and polyenoic acids.     

Synthesis of New α-Heterocyclic α-Aminophosphonates

α-heterocyclic α-aminophosphonates were obtained in good yields by N-of several nitrogen heterocycles with α-azido-α-aminophosphonate 1. ¹ Elachqar, A., El Hallaoui, A., Roumestant, M. L. and Viallefont, Ph. 1994. Synthetic Comm, 24: 1279 [CSA][Taylor & Francis Online], [Web of Science ®] , [Google Scholar]     

A New Convenient Synthesis of α-Arylpropionic Acid Esters and α-Arylpropionitriles

Various types of α-arylpropionic acid esters were effectively obtained by the coupling reaction of aryl Grignard reagents and α-bromopropionic acid esters in the presence of nickel catalysts. α-Arylpropionitriles, precursors of α-arylpropionic acids, were also synthesized by the reaction of α-methanesulfonyloxypropionitrile and arylcopper reagents prepared from equimolar amount of arylmagnesium halides and copper(I) bromide.     

New general synthesis of α-alkoxyketones via α'-alkylation, α-alkylation and α,α'-dialkylation of α-alkoxyketimines

α-Methoxy- and α-ethoxyketones, as important intermediates in organic synthesis and flavor compounds in food chemistry, were synthesized by deprotonation of N-(1-alkoxy-2-propylidene)isopropylamine, prepared by condensation of the corresponding α-alkoxyacetone with isopropylamine, and subsequent reaction of the corresponding 1-azaallylic anions with alkyl halides to afford α'-alkylated, α-alkylated and α,α'-dialkylated ketimines. Hydrolysis of the imino function led to the desired substituted α-alkoxyketones. The ratio of α-, α'-, and α,α'-(di)alkylated compounds depended on the amount of base used and on the nature of the alkylating reagent.     

New method of preparing β-lactams

Summary A method has been devised for the synthesis of B-lactams from amides of -halocarboxylic acids, Some new azetidinones with residues containing carboxyl groups on the nitrogen have been prepared. The method permits the conversion of -amino acids into difficulty accessible mixed (secondary) amino acids.     

New method of preparing β-lactams

Summary A method has been devised for the synthesis of -lacrams from amides of -ha!ocarboxylic acids. Some new azetidinones with residues containing carboxyl groups on the nitrogen have been piepated. The method permits the conversion of $-amino acids trio difficulty accessible mixed (secondary) amino acids.This paper is publised under the regulations governing Brief Communications.     

New method in synthesizing an optical active intermediate for （R,R）-formoterol

（R）-1-（4-Methoxyphenyl）propan-2-amine 2a, an optical active intermediate for （R,R）-formoterol, was synthesized from Dalanine in 65% overall yield by using a simple route, which contained protecting amino group, cyclization, coupling with Grignard reagent, reduction and deprotection.     

Domino Friedel-Crafts-type cyclizations of difluoroalkenes promoted by the α-cation-stabilizing effect of fluorine: an efficient method for synthesizing angular PAHs

In order to synthesize polycyclic aromatic hydrocarbons with nonlinear arrangements (angular PAHs), acid‐promoted domino cyclizations of 1,1‐difluoroalk‐1‐enes and 1,1‐difluoroalka‐1,3‐dienes were studied. 1,1‐Difluoroalkenes, each bearing two aryl substituents, were regioselectively protonated with FSO₃H?SbF₅ to generate fluorine‐stabilized carbocations, which readily underwent domino Friedel–Crafts‐type cyclizations to give carbocycles based on 6/n/m/6 ring systems (n,m=5–7) in good to high yields. Protonation of 1,1‐difluoroalka‐1,3‐dienes took place at their electron‐rich methylene (CH₂) carbon atoms in the presence of milder acids such as camphorsulfonic acid and trifluoromethanesulfonic acid. Domino cyclizations of the resulting fluorine‐stabilized allylic carbocations afford carbocycles based on 6/6/6/6 or 6/6/5/6 ring systems in high yields.     

A mild and general method for preparation of α-glycosyl chlorides

A mild and efficient chlorination method for production of glycosyl chlorides is first described which employs inexpensive trichlorotriazine (TCT) and DMF as a chlorination reagent and is compatible with typical acid-labile hydroxyl protecting functions. The scope and limitations, reaction mechanism and its application in the sequential glycosylations are discussed.     

One-pot method for α-phenylation of ketones using isoxazolidine and triphenylaluminum

The efficient one-pot umpolung α-phenylation of ketones via N-alkenylisoxazolidine is described. When the various ketones are treated with triphenylaluminum prepared from phenylmagnesium chloride and AlCl₃ in the presence of isoxazolidine, the desired products are obtained in good to moderate yield. This method is equivalent to a direct α-arylation reaction of carbonyl groups.     

New Chemistry of α-Silyl Vinylsulfides

α-Silyl Vinylsulfides, obtained in a stereoselective manner through enethiolizable silyl thioketones, can be used for the synthesis of vinylsulfides and vinylsilane with a specific geometry, and for the preraration of bicyclic and open chain thiofunzionalized enones.     

A rapid method toward the synthesis of new substituted tetrahydro α-carbolines and α-carbolines

A rapid and efficient method for stereoselective synthesis of new substituted tetrahydro-α-carbolines using Diels-Alder reaction under microwave irradiation has been developed. Further, dehydrogenation of these adducts resulted in synthesis of new substituted α-carbolines.     

New and selective HPTLC—Densitometric method for determination of pioglitazone hydrochloride

JPC – Journal of Planar Chromatography – Modern TLC - New sensitive and selective HPTLC-densitometric method has been developed for the determination of pioglitazone hydrochloride. The...     

p-Alkoxy- and p-alkylbenzoates of α, a'-bi-p-hydroxytoluene. New series of liquid-crystalline compounds

Abstract

Six p-alkoxy and eight p-alkylbenzoates of 1,2-(p-hydroxyphenyl)ethane were synthesized for potential use as stationary phases in gas-liquid chromatography. All the p-alkoxy derivatives were nematic. The first five members of the alkyl series were nematic and the rest exhibited both smectic and nematic character. Most possess the desired combination of a wide liquid-crystalline temperature range and a high mesomorphic-isotropic transition temperature. The nematic-isotropic transition temperatures and entropies show the usual alternations characteristic of a high-melting series.     

Application of ACC method to synchronous luminiscence: determination of α-tocopherol and α-tocopheryl acetate in beverages

A new method based on the Q parameter, that permits the determination of the C_{compound A} /C_{compound B} ratio without preparing calibration graphs of the two compounds, is proposed. This method has been applied to signals obtained by synchronous luminiscence. Simultaneous determination of α-tocopherol and α-tocopheryl acetate in beverages using synchronous fluorescence has been carried out. To isolate the compounds from samples, liquid extraction with n-hexane as the organic phase was employed. The presence of interferences was tested using the apparent content curves (ACC) method and the C_{α-tocopherol}/¶C_{α-tocopheryl acetate} ratio was calculated using the Q parameter. The reproducibility and detection limit for the determination of α-tocopherol and α-tocopheryl acetate were 6.6% and 0.016 mg/L and 1.8% and 0.017 mg/L, respectively.     

Efficient method for the asymmetric reduction of α- and β-ketophosphonates

An efficient and versatile method for the asymmetric reduction of α- and β-ketophosphonates using chiral reactant derived from sodium borohydride and l-(+)- or d-(−)-tartaric acid is developed. The methodology was used for the preparation of a number of biologically interesting enantiomerically pure products: including 2,3-epoxypropylphosphonate 11, 2-hydroxy-3-aminopropylphosphonic acid 14 (phospho-GABOB), phospho-carnitine 19, and others in multigram scale.     

A highly efficient method for the α,β-dehydrogenation of α-amino esters and α-amino-β-diesters

N-monochlorination of N-unprotected α-amino esters and α-amino-β-diesters was efficiently and very simply effected by using inexpensive effervescent sodium dichloroisocyanurate tablets for water disinfection in a biphasic organic solvent-water system. Subsequent dehydrochlorination provided α,β-didehydroaminoacid esters, whose hydrogenation would allow the starting compounds to be easily racemized.