Molecular and crystal structure of 1,1-bis(methoxy-NNO-azoxy)-3,3,3-trinitropropane

The crystal structure of 1,1-bis(methoxy-NNO-azoxy)-3,3,3-trinitropropane is studied.     

Alkylation of phosphine boranes by phase-transfer catalysis

The alkylation of phosphine boranes with various electrophiles proceeds with good to excellent yields in a biphasic solution in the presence of tetrabutylammonium bromide as a phase-transfer catalyst. [reaction: see text]     

Alkylation of hetaryl methyl ketones by propargyl bromide under phase-transfer catalysis conditions

The alkylation of aryl and hetaryl methyl ketones by propargyl bromide using the phase-transfer catalysis system KOH (s)/18-crown-6/benzene is studied. The corresponding C-trialkylated products are selectively obtained in 34–78% yields. Dedicated to Professor Henk van der Plas on his 70th birthday. Latvian Institute of Organic Synthesis, Riga LV-1006, Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 495–497, April, 1999.     

Synthesis of 1-(2-aminoethyl)pyrazoles under phase-transfer catalysis

Alkylation of pyrazoles with 2-chloroethylamine was performed under conditions of phasetransfer catalysis. Depending on the substrate acidity, the electrophilic substitution process may be accompanied by dehydrochlorination of the alkylating agent, so that 6 equiv of 2-chloroethylamine should be used in the alkylation of 3,5-dimethylpyrazole.     

Synthesis of monoazacrown ethers under phase-transfer catalysis

A procedure has been proposed for the synthesis of monoazacrown ethers by reaction of N-benzyldiethanolamine with oligo(ethylene glycol) bis-p-toluenesulfonates in a two-phase system aromatic hydrocarbon-50% aqueous alkali, followed by removal of the benzyl group by catalytic hydrogenolysis. The maximal yields of N-benzylaza-12-crown-4, -18-crown-6, and -21-crown-7 were achieved by adding 4?C10 equiv of LiCl, BaBr₂, and CsCl, respectively, to the reaction mixture, which probably indicated template effect.     

One-pot method for synthesis of 2-substituted 1,1-di(methoxy-NNO-azoxy)ethanes

One-pot method was developed for synthesis of 2-substituted 1,1-di(methoxy-NNO-azoxy)ethanes from 2,2-di(methoxy-NNO-azoxy)ethanol in three chemical stages.     

S-benzylation of arylidene thiobarbituric acids under phase-transfer catalysis

Russian Journal of General Chemistry -     

Alkylation of sterically hindered 1,3-diketones under phase-transfer conditions

Sterically hindered 1,3-diketones react selectively with propargyl and allyl bromides under conditions of phase transfer catalysis to giveC-alkylated products, whereas reactions with butyl and benzyl chlorides yield mixtures ofC- andO-isomers. An increase in the size of the substituents present in the initial 1,3-diketone hampers introduction of the second propargyl group. The propargyl-substituted 1,3-diketones undergo cyclization under the alkylation conditions to give substituted furans.     

Synthesis of 4-(diethylamino)-3-methylbutan-2-ol under conditions of phase-transfer catalysis

Russian Journal of Organic Chemistry -     

Reactions of 2,2-bis(trifluoromethyl)oxirane with alcohols under phase transfer catalysis

It was demonstrated that the reaction of 2,2-bis(trifluoromethyl)oxirane (1) with variety of alcohols could be successfully carried out under phase transfer catalysis conditions using sodium or potassium hydroxide as a base. For example, reaction of CH₃OH, C₂H₅OCH₂CH₂OH, HOCH₂CH₂OH with one or two moles of 1 in the presence of the catalyst [(C₄H₉)₄N⁺HSO₄⁻] gives the corresponding tertiary alcohols R[OCH₂C(CF₃)₂OH]_n (n=1 or 2) in 43-53% yield, along with some O[CH₂C(CF₃)₂OH]₂. Benzyl alcohol and phenol under similar conditions are less active, producing in the reaction with 1 the corresponding adducts ArOCH₂C(CF₃)₂OH in 31-35% yield. Fluorinated alcohols, such as CF₃CH₂OH, ClCF₂CH₂OH, HCF₂CF₂CH₂OH have much higher reactivity towards 1 giving ring opening products in 82-97% yield. Even in the reaction of hindered hexafluoro-iso-propanol the corresponding adduct was isolated in 43% yield. Surprisingly, the reaction of iso-propanol and epoxide 1, results in the formation of O[CH₂C(CF₃)₂OH]₂ as a major product, isolated in 56% yield. Possible mechanism for the formation of the last product was proposed.     

Simple synthesis of 1,1-bis(trifluoromethyl)cyclopropanes

A new, simple synthesis of 1,1-bis(trifluoromethyl)cyclopropanes has been discovered. It is based on the reaction of readily available 2,2-bis(trifluoromethyl)thietanes with tertiary phosphines in a polar solvent, which leads to an unusual desulfurization process, resulting in the formation of 1,1-bis(trifluoromethyl)-2-alkoxy cyclopropanes. The process of the corresponding thietanes appears to be sensitive to the steric volume of the atom connected to carbon in α-position to sulfur.     

Alkylation of pentaerythritol by phase-transfer catalysis : 2. Crucial effect of the aqueous sodium hydroxide solution

The mechanistic aspects of the alkylation of pentaerythritol (2-2'-bis(hydroxymethyl)-l,3-propanediol) (PE) by phase-transfer catalysis have been investigated. The dramatic effect of an excess and renewal of sodium hydroxide solutions on the one hand, and the solubility of the PT catalyst in the organic phase on the other, argue that the selectivity of this reaction appears to be controlled almost completely by the possible protonation of the sodium form of the alkoxide anion of PE (4). This protonation depends on the assumption that water molecules are present in the PT medium, and is based upon the observation that this PT medium is actually a three liquid-layer system. As the unusual layer (catalyst layer) may be readily hydrated, the concentrated sodium hydroxyde solution can be no longer considered as an unquestionable desiccant.     

Synthesis of 1,1-bis(methoxy-NNO-azoxy)-3,3,3-trinitropropane from 1,1-bis(methoxy-NNO-azoxy)ethene and nitroform

A reaction of 1,1-bis(methoxy-NNO-azoxy)ethene with nitroform at ∼20 °C gave 1,1-bis-(methoxy-NNO-azoxy)-3,3,3-trinitropropane.     

Synthesis of indan-based unusual alpha-amino acid derivatives under phase-transfer catalysis conditions

Conformationally constrained cyclic alpha-amino acid derivatives were synthesized under solid-liquid phase-transfer catalysis conditions. This methodology involves the bis-alkylation of ethyl isocyanoacetate with various alpha,alpha'-dibromo-o-xylene derivatives [alpha,alpha'-dibromo-o-xylene 5, 2,3-bis(bromomethyl)-1, 4-dimethoxybenzene 6, 1,2-bis(bromomethyl)-4,5-dibromobenzene 7, 2, 3-bis(bromomethyl)naphthalene 8, 1,8-bis(bromomethyl)-naphthalene 9, 6,7-bis(bromomethyl)-2,2-dimethyl-1H-phenalene-1,3(2H)-dione 10, 2, 3-bis(bromomethyl)-1,4-anthraquinone 11, 6, 7-bis(bromomethyl)quinoxaline 12, 3,4-bis(bromomethyl)furan 13, 1,2, 4,5-tetrakis(bromomethyl)benzene 28, and hexakis(bromomethyl)benzene 30] using potassium carbonate as a base and tetrabutylammonium hydrogensulfate as a phase-transfer catalyst to give corresponding isonitrile derivatives, which upon hydrolysis with HCl in ethanol gave amino esters. Using this method electron-deficient as well as electron-rich and halogen-substituted indan-based alpha-amino acids were prepared. The preparation of bis-indan as well as tris-indan alpha-amino esters is also described.