Synthesis of phenoxypyridines under phase transfer catalysis conditions

Reactions of halopyridines with alkali metal phenoxides in a two phase liquid-solid catalytic system, rather than in a liquid-liquid phase transfer catalytic system, make it possible to prepare 2-, 3-, and 4-phenoxypyridines from unactivated bromo- or chloropyridines and 2-chloropicolines. In polyhalogenated pyridines only - and -halogen atoms undergo substitution. 7, 8-Dibromo-6-azaphenoxane has been prepared by the reaction of 2,3,5,6-tetrabromopyridine with the dipotassium salt of pyrocatechol.Translated from Khimiya Geterotsiklicheskikh Soedinenii, Vol. 24, No. 3, pp. 356–360, March, 1988.     

Autooxidation of methylheterocycles under phase transfer catalysis conditions

The autooxidation of methyl- and dimethyl-substituted N-, S-, and O-heterocyclic compound derivatives has been studied in 1,2-dimethoxyethane—t-BuOK in the presence of 18-crown-6. Mono- and dicarboxylic acid derivatives of pyrazine, pyridine, pyrimidine, and thiophene have been synthesized.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 959–962, July, 1991.     

Wittig and Wittig-Horner reactions under phase transfer catalysis conditions

Wittig and Wittig-Horner reactions are favorite tools in preparative organic chemistry. These olefination methods enjoy widespread and recognition because of their simplicity, convenience, and effciency. Phase transfer catalysis (PTC) is a very important method in synthetic organic chemistry having many advantages over conventional, homogenous reaction procedures. In this paper, we attempt to summarize the aspects concerning Wittig and Wittig-Horner reactions that take place under phase transfer catalysis conditions.     

Regioselective arylation of unsaturated silanes under phase transfer catalysis conditions

Conclusions The regioselective arylation of unsaturated compounds was carried out under metal complex and phase transfer conditions by the action of aryl iodides.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 5, pp. 1180–1183, May, 1988.     

Synthesis of aromatic fluorides by the reaction of fluorohalocarbenes with cyclopentadiene derivatives under phase transfer catalysis conditions

Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 8, p. 1935, August, 1989.     

Efficient synthesis of dithioacetals of α-oxoketene and dithiofulvenes under phase transfer catalysis conditions

Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 1, pp. 213–214, January, 1989.     

Alkylation of carbohydrates by phase transfer catalysis

From partially tetrahydropyranylated intermediates, carbohydrates (meso-erythritol and sorbitol) can be easily alkylated using phase transfer catalysis.     

Acylation of phosphoryl- and thiophosphorylacetonitriles under phase transfer catalysis conditions and the keto-enol tautomerism of phosphorus-substituted acylacetonitriles

A procedure was developed for acylation of phosphoryl- and thiophosphorylacetonitriles under phase transfer catalysis conditions. The reaction in the solid KOH/MeCN system affordedC-acylation products in high yields. In the individual state and in aprotic solvents, these products exist in the enol form (Z isomers) stabilizedvia a strong intramolecular hydrogen bond. In hydroxyl-containing media and in aprotic bipolar solvents, these compounds exist as a mixture of two geometric isomers (E andZ) of the corresponding enols. In this case, theZ isomer exists in two forms, namely, in the cyclic form with an intramolecular hydrogen bond and in the open form stabilized by intermolecular hydrogen bonds with the solvent. The results of X-ray diffraction analysis of both forms ofZ isomers of the compounds containing the phosphoryl and thiophosphoryl groups are discussed. Deceased. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1687–1694, September, 1998.     

Some transformations of 2-benzylcyclododecanones prepared by alkylation of cyclododecanone with benzyl halides under conditions of phase transfer catalysis

Cyclododecanone is readily alkylated with benzyl halides (ArCH₂X) to give 2-benzylcyclododecanones under conditions of phase transfer catalysis. Under the action of polyphosphoric acid 2-benzylcyclododecanone undergoes cyclization to give 1,2,3,4,5,6,7, 8,9,10-decahydrocyclododeca[b]indene. It also reacts with NOCl to give 12-hydroxyimino-2-benzylcyclododecanone, which enters the Beckmann rearrangement to afford 2-benzyl-1,12-dodecandioic acid.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 905–907, May, 1993.     

Difluoromethylation of some C-H acids with chlorodifluoromethane under conditions of phase transfer catalysis (PTC)

Selected C-H acids react with difluorocarbene generated from chlorodifluoromethane with concentrated aqueous solution of sodium hydroxide, and a catalyst, benzyltriethylammonium chloride (TEBAC) in benzene or THF affording C-difluoromethyl substituted derivatives. This process is restricted to C-H acids of pK_a ≅ 16.3-19.1. The observed facts are rationalized.     

Cyclopropanation of betulonic acid and its methyl ester with dichlorocarbene generated under phase transfer catalysis conditions

The addition of dichlorocarbene generated under phase transfer catalysis conditions to the double bond of betulonic acid occurs stereoselectively and is accompanied by transformation of the carboxy group leading to the dichloromethyl ester and chloride of 3-oxo-20,29-(dichloromethano)lupan-28-oic acid. Together these products, the chloride of the starting betulonic acid is formed depending on the reaction conditions. The reaction of dichlorocarbene with methyl betulonate leads to the corresponding cyclopropane adduct in a quantitative yield. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 2574–2578, November, 2005.