E. Abele

Prototropic Rearrangement of 2-Propynyl(methyl)amino, 2-Propynyloxy, and 2-Propynylsulfanyl Derivatives of Hetarenes under Conditions of Phase-Transfer Catalysis: Mechanism and Limitations

Abstract2-Propynyl derivatives of N-methylaniline, phenol, benzenethiol, 2-pyridinethiol, 2-pyrimidinethiol, and 1,3-benzoxazole-2-thiol were synthesized. Under conditions of phase-transfer catalysis, phenyl 2-propynyl sulfide is converted into allenyl phenyl sulfide and phenyl 1-propynyl sulfide. The rearrangement mechanism was studied by the AM1 quantum-chemical method.

Synthesis, structure, and cytotoxicity of O-[3-(5-tetrazolyl)propyl]oximes

A two-stage method was developed for the conversion of phenyl-and pyridylaldoximes and ketoximes into the corresponding O-[3-(5-tetrazolyl)propyl]oximes. The structure of the sodium salt of 2-acetylpyridine O-[3-(5-tetrazolyl)propyl]oxime was established X-ray diffraction analysis. This compound was shown to possess a high cytotoxic activity in vitro.

O-Alkylation of furan and thiophene ketoximes in conditions of interphase catalysis in a liquid/solid system

Alkylation of 2 furanyl- and 2-thienylalkyl ketoximes with alkyl, allyl, and propargyl halides in the two phase catalytic system sol. K2CO3/C6H6/18-crown-6 at room temperature causes the formation of mixtures of E- and Z-isomers of the corresponding O-ethers with yields of 32–74%. Partial E/Z-isomerization takes place during the reaction.

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.

ALKYLATION OF 3-ACETYLTHIOPHENE UNDER PHASE-TRANSFER CONDITIONS

Abstract Reactions of 3-acetylthiophene with C1-C4-alkyl iodides in a two-phase benzene/solid KOH system in the presence of l8-crown-6 afford di-C-alkylated derivatives-(3-thienyl)COCHR2 in satisfactory yields (∼50%) with high regioselectivity (70–100%).

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.

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

SummaryReactions 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.

Inclusion complexes of prochiral heterocyclic ketones with ?-cyclodextrins and their reduction with sodium borohydride

Alkyl(2-furyl), alkyl(2-thienyl), and methyl pyridyl ketones form stoichiometric inclusion complexes with β-cyclodextrins. Reduction of these complexes in aqueous solution of Na2CO3 at room temperature yields the corresponding secondary alcohols with an optical yield which attains 27%.

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 α- and γ-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.

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.