O-acylation of ketoximes of the furan and thiophene series in the liquid-solid body system under interphase catalysts conditions

The acrylation of 2-furanyl- and 2-thienylalkylketoximes by acyl chlorides in a two-phase catalytic system (solid K₂CO₃-C₆H₆-18-crown-6) at room temperature leads to a selective formation of the corresponding O-acetylketoximes in the form of a mixture of E- and Z-isomers.Latvian Institute of ORganic Synthesis, Riga, LV-1006. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 886–890, July, 1994. Original article submitted April 12, 1994.     

Synthesis of alkyl heteryl ethers from acetates under interphase catalysis conditions in a liquid/solid system

The reaction of acetates of heterocyclic alcohols with alkyl halides in the two-phase catalytic system of solid KOH/C₆H₆/18-crown-6 at room temperature leads selectively to the formation of the corresponding heterocyclic ethers in 32–93% yield.Latvian Institute of Organic Synthesis, Riga LV-1006, e-mail: kira@osi.lanet.lv. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 46–49, January, 1998.     

Halogenation of propargyl ethers of heterylaldoximes and ketoximes under interphase catalysis conditions

The halogenation of propargyl ethers of heterylaldoximes and ketoximes in interphase catalytic systems CX₄ (X=Cl, Br)/solid KOH/18-crown-6 leads selectively to the formation of the corresponding O-(halopropargyl)oximes. Latvian Institute of Organic Synthesis, Riga LV-1006. e-mail: kira@osi.lanet.lv. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1325–1328.     

Synthesis and alkylation of pyridylacetylenes under phase transfer catalysis conditions in a liquid/solid system

We have investigated the alkylation of 2-methyl-5-ethynylpyridine by butyl bromide in liquid/liquid and liquid/solid two-phase catalytic systems. We have shown that the catalytic system solid KOH/18-crown-6/CuBr/toluene is the most active in this reaction; using this system, we obtained alkylation products of ethynylpyridines in 34–43% yields.Latvian Institute of Organic Synthesis, Riga LV-1006. Translated from Khimiya Geterotsikicheskikh Soedinenii. No. 4, pp. 518–521, April, 1998.     

Synthesis of nitrogen-containing cryptands under interphase catalysis conditions

Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, p. 1000, July, 1989.     

Reactions of alkyl hetaryl ketones with carbon tetrachloride under liquid/solid phase-transfer catalysis conditions

Summary Reactions of methyl and ethyl hetaryl ketones in the CCl₄/solid KOH system in the presence of 18 crown-6 at room temperature yield the corresponding 2-hetaryl-2-trichloromethyloxiranes in 8–22% yields. Reactions of sterically hindered ketones of the type (hetaryl)COCHR₂ (R = Me, Et) with CCl₄/OH- form the corresponding a-hydroxy ketones of the type (hetaryl)COC(OH)R₂ in 28–44% yields.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 312–315, March, 1994.     

O-Alkylation of a lignite humic acid by phase-transfer catalysis

A mild phase-transfer catalytic reaction has been conducted to O-alkylate the acidic functions of a lignite humic acid (HA), using tetrabutylammonium hydroxide as the phase-transfer catalyst. The HA acidic functional groups were made to react, in tetrahydrofuran, by nucleophilic substitution with several alkyl halides—methyl iodide, and ethyl, propyl, and butyl, and benzyl bromide. The occurrence of the O-alkylation reaction was assessed by elemental analysis and ¹H NMR, CPMAS ¹³C NMR, and FTIR spectroscopy. Bonding of alkyl groups increased the carbon and hydrogen content and the H/C ratios of all the humic reaction products. Increased nitrogen in the reaction products suggested incomplete removal of the phase-transfer catalyst after purification of the alkylated HA. ¹H NMR and CPMAS ¹³C NMR spectra of alkylated products provided evidence of the successful occurrence of the alkylation reactions. Infrared spectra confirmed the NMR results, revealing the characteristic absorption of newly formed alkyl and aryl ethers and esters in the alkylated products and C–H stretching in the aromatic ring of the benzylated derivative. These findings indicate that humic matter can be successfully alkylated with several different alkylating groups by catalysed phase-transfer reaction. This O-alkylation reaction has the advantage of being mild, versatile, and high-yielding compared with traditional methylation reactions applied to HA. The possibility of introducing different alkyl groups into the HA by a mild phase-transfer reaction may become useful by enabling improved fractionation of humic supramolecular associations and further understanding of the molecular nature of humic substances.     

Chemistry of furan and thiophene compounds

1-(-Furyl)pentan-1-ol-3-one and 1-(-thienyl)pentan-1-o1-3-one were synthesized by the reaction of furfural and -formylthiophene with methyl ethyl ketone. The products were used to synthesize secondary-tertiary -glycols with -furyl and -thienyl groups attached to the secondary carbinol carbon. It was proved that these -glycols are capable of undergoing hydrolytic cleavage at the C₂–C₃ bond.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 295–297, March, 1972.     

Alkylation of some 6-substituted purines under interphase catalysis conditions

The mixture of 9-, 3-, and 7-benzyl-6-substituted purines is formed in almost quantitative yield by the alkylation of 6-benzylamino-, 6-furfurylamino-, 6-methylthio-, and 6-chloropurine with benzyl halides in the biphasic system of the liquid-liquid or liquid-solid type in the presence of interphase catalysts (quaternary ammonium salts, 18-crown-6). The catalytic activity of the quaternary ammonium salts increases with the increase in the lipophilicity of the cation. Taking the alkylation of 6-benzylaminopurine as an example, the possibility of the application of triphasic catalysis in the alkylation reaction of purines is indicated. The alkylation of 6-substituted purines with isopropyl bromide proceeds regioselectively under the conditions of the interphase catalysis with the formation of the corresponding 9-isopropylpurines.For the preliminary communication, see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 113–118, January, 1987.     

Synthesis of some derivatives of indole and indoloindoles under conditions of interphase catalysis

The preparation of N-alkyl and N,N-dialkyl derivatives of indole, 3H,8H-indolo[4,5-e]-, 3H,8H-indolo[5,4-e]-, and 1H,6H-indolo[7,6-d]indole under conditions of interphase catalysis is studied. In the case of indole, it is found possible to form 1,3-dipropargylindole.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 464–467, April, 1991.     

Facile dearomatizing radical arylation of furan and thiophene

In the presence of catalytic diphenyl diselenide, reduced in situ to benzeneselenol, tributyltin hydride and V-70 promote the addition of aryl iodides to furan and thiophene. The adduct radicals are trapped by the selenol to give the 2-aryl-2,3-dihydro and 2-aryl-2,5-dihydro heterocyclic products. When the iodide is an o-iodophenol, a cyclization follows the radical addition and provides bridged bicyclic acetals. [reaction: see text]     

An unusual reaction of trichloromethane with acylals in the interphase catalysis conditions.

Aldehyde diacetates react with trichloromethane in the standard interphase catalysis conditions to form α-trichloromethylcarbinols or their acetates depending on temperature and time of the reaction.     

Studies of selenides of thiophene and furan series—V: Mass spectra of some thiophene,furan and selenophene derivatives

Mass spectra of some selenides, sulphides and ethers of furan, thiophene and selenophene series are described. A new fragmentation reaction, consisting in splitting off alkyl, insertion of heteroatom in the cycle and loss of one of heteroatoms as C?X, is discussed in detail.     

Synthesis of trichloromethyl-substituted azines from dichloromethyl-substituted azines and carbon tetrachloride under interphase catalysis conditions

The reactions of 2- and 3-dichloromethylpyridines and dichloromethylpyrazine with carbon tetrachloride in the presence of aqueous or solid alkali and an interphase catalyst lead to the corresponding trichloromethyl-substituted azines. The CCl₄-solid KOH-18-crown-6 system, in the use of which trichloromethyl-substituted heterocycles were obtained in preparative yields, was the most effective.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 50–53, January, 1990.