Reaction of Lithium Acylate α-Carbanions with Carbon Tetrachloride

Russian Journal of Organic Chemistry - Metalation of acetic, butanoic, or 2-methylpropanoic acid with lithium diisopropylamide in tetrahydrofuran under argon gave the corresponding lithium acylate...     

Reaction of Lithium Acylate α-Carbanions with Carbon Tetrabromide

Russian Journal of Organic Chemistry - Lithium acylate α-carbanions generated by metalation of acetic, butanoic, and 2-methylpropanoic acids with lithium diisopropylamide in THF under argon...     

Low-Temperature Reactions of α-Bromopropanoyl Chloride with Lithium Derivative of Ethyl Acetate

The reaction of 2-bromopropanoyl chloride with lithium ethyl acetate generated in situ by the reaction of equimolar amounts of lithium diisopropylamide with ethyl acetate forms, depending on the conditions (temperature, time, reagent ratio), diethyl 2,2′-(3-methyloxirane-2,2-diyl)diacetate, 2,2-dibromo-N,N-diisopropylpropanamide, and ethyl (5-methyl-4-oxo-4,5-dihydrofuran-2-yl)acetate as minor by-products along with the expected acylation product ethyl 4-bromo-3-oxopentanoate. The reaction with 2 or 5 equiv of lithium ethyl acetate (–78°C → –20°C) gave, together with the mentioned α-bromo ester, ethyl (5-methyl-4-oxo-4,5-dihydrofuran-2-yl)acetate formed as a result of transformations of the adduct of the second LiCH₂CO₂Et molecule and ethyl-4-bromo-3-oxopentanoate. The reaction 2-bromopropanoyl chloride with sodium malonic ester involves acylation of enol form of the primary expected acylation product to afford dimethyl |2-bromo-1-[(2-bromopropanoyl)oxy]propylidene-malonate.

     

Reactions of α-halonitrosoalkanes with resorcinol

-Halonitrosoalkanes react with resorcinol as nitrosylating agents to form 3-hydroxy-N-(2,4-dihydroxyphenyl)-1,4-quinone imine.Translated fromIzvestiya Akademioi Nauk. Seriya Khimicheskaya, No. 3, pp.773–774, March, 1996.     

Reactions of α-nitroacrylates with thiophenols

Reactions of α-nitroacrylates with aromatic thiols like 4-methyl- and 4-chlorothiophenols afford a series of new 3-arylsulfanyl-2-nitropropanoates. The latter were isolated as diastereomerically pure substances or mixtures of two diastereomers. Structures of the obtained S-adducts were confirmed by IR, ¹H and ¹³C-{¹H} NMR spectroscopy using HMQC and HMBC experiments.     

Reactions of 1,2-diaminobenzimidazoles with β-dicarbonyl compounds

The reactions of 1,2-diaminobenzimidazoles with β-dicarbonyl compounds give 1,2,4-triazepino [2,3-a]benzimidazole and pyrimido [1,2-a]benzimidazole-derivatives.     

Reactions of alkylidenepyrrolidines with α-chlorooximes and α-chlorohydrazones

The reactions of alkylidenepyrrolidines with α-chlorooximes give isoxazoles via an acylation reaction followed by ring isomerisation. In contrast, and in line with a previous report, the corresponding α-chlorohydrazones give the simple acylation products, although in one instance a cycloadduct was also obtained.     

Reactions of α-aminoazoles with diethyl benzylidenemalonate

Cyclocondensations of diethyl benzylidenemalonate with 3-amino-5-methylpyrazole, 3,5-diamino-1,2,4-triazole, 3,4,5-triamino-1,2,4-triazole, and 2-amino-benzimidazole in alcohols take a single route and lead to the formation of functionally substituted partially hydrogenated pyrazolo-, triazolo[1,5-a]-pyrimidin-5-ones and pyrimido[1,2-a]benzimidazol-2-one respectively. From reaction mixtures involving 3-amino-1,2,4-triazole and its 5-methylsulfanyl analog in methanol the intermediate products of heterocyclization were isolated forming as a result of alkylation with the β-carbon of the unsaturated ester the endocyclic nucleophilic sites of aminoazoles. The structure of one among the products obtained, diethyl(3-amino-5-methylsulfanyl-1,2,4-triazol-2-yl)benzylmalonate was proved by X-ray crystallography. In DMF the same reagents yielded mixtures of partially hydrogenated triazolo[1,5-a]pyrimidin-5-ones.     

Reactions of α-pentafluorophenylpyrylium salts with hydroxylamine

The reactions of α-pentafluorophenylpyrylium salts with hydroxylamine in ethanol afford isoxazoline derivatives and/or pyridine N-oxides depending on the steric characteristics of the substituent in the second α position. The structure of 2-hydroxy-2-pentafluorophenyl-4-phenyl-2,3,5,6,7,8-hexahydroquinoline 1-oxide, which was synthesized by the reaction of 2-pentafluorophenyl-4-phenyl-5,6,7,8-tetrahydrobenzopyrylium perchlorate with NH₂OH, was established by X-ray diffraction. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 402–407, February, 2008.     

Reactions of α-difluoro azides with olefins

Reactions of α-difluoro azides with olefins result in oxidative fluoroamination or amination of the C=C bond.     

Reactions of 3-aroylacrylates with α-aminoazoles*

Dihydro derivatives of pyrazolo[3,4-b]pyridine-, pyrazolo[1,5-a]pyrimidine-, and [1,2,4]triazolo-[1,5-a]pyrimidinecarboxylates have been prepared by cyclocondensation of β-aroylacrylates with 5-aminopyrazoles and 3-amino-1,2,4-triazole. Heating dihydro[1,2,4]triazolo[1,5-a]pyrimidine-7-carboxylates with hydrazine hydrate led to recyclization of the pyrimidine ring to form 6-arylpyridazin-3(2H)-ones.     

Reactions of α-perfluorophenylpyrylium perchlorates with hydrazine hydrate

Reactions of α-perfluorophenylpyrylium salts with hydrazine hydrate in ethanol afforded derivatives of 1,2-diazepine, dihydro-1H-pyrazole, and/or 1-aminopyridinium salts, depending on the steric characteristics of the substituent in the second α-position. 1-Amino-2-methyl-6-perfluorophenyl-4-phenylpyridinium perchlorate was used to obtain various pyridocyanines.     

Reactions of bicyclic phosphonates with halides of α-halocarboxylic acids

Novel types of substituted framework phosphonates have been synthesized via functionalization of bicyclic compounds obtained in the reaction of 2-ethoxyvinyl dichlorophosphonate with different phenols. The reactions of functionalized bicyclic phosphonates with triphenyl phosphine have been studied; antimicrobial activity of the prepared compounds has been investigated.     

Reactions of cyclic α-methoxy nitrones with nucleophilic reagents

Reactions of cyclic -methoxy nitrones, which are derivatives of imidazole or dihydroimidazole N-oxides, with amines, KOH, or KSH result in the replacement of the MeO group to form cyclic -amino nitrones, hydroxamic acids, or thiohydroxamic acids, respectively. Analogous reactions occur with C-nucleophiles.     

Reactions of Phosphorodiamidous Acid Esters with α-Halocarbonyl Compounds

Reactions of ethyl and tert-butyl phosphorodiamidites with chloroacetone, bromoacetone, and -chloroethyl acetate were studied. The reaction pathway is determined by the structure of the intermediate quasiphosphonium compound responsible for the formation of the Arbuzov product as well as for the occurrence of the amonalous reaction yielding vinyl phosphate.     

Reaction of α-carbanions of lithium acylates with 1,2-dibromoethane

The reaction of 1,2-dibromoethane with α-carbanions of lithium acylates generated from acetic, butyric, isobutyric, and capronic acids with lithium diisopropylamide has been studied. Anion-radical and anionic pathways of the products formation have been discussed.     

Reactions of α-chloro β-oxo aldehydes with CH-acid anions

The reactions of α-chloro and α,α-dichloro β-oxo aldehydes with carbanions are accompanied by the cleavage of the carbon-carbon bond in the chloro aldehydes and result in formylation of CH-acids. These electrophiles react with carbanions, which are generatedin situ from CH-acids in the presence of AcONa in aprotic solvents, to form polyfunctional hydroxy compounds.     

Reactions of α-fluorine-containing β-functionalized vinyl sulfides with N-nucleophiles

-Fluorine-containing -functionalized vinyl sulfides readily react with N-nucleophiles to form -fluorine-substituted products. The reactions with phenylhydrazines and amidines of acids are accompanied by cyclization at the functional group. Thermal cyclization of cyanotrifluoromethylketene N,S-acetals proceeds at the trifluoromethyl group to give substituted 3-cyanoquinolin-4-ones.