Superbasic System Research Articles

First example of favorskii ethynylation of pyrrolecarbaldehydes: Synthesis of 1-(1-methyl-1H-pyrrol-2-yl)prop-2-yn-1-ol

1-(1-Methyl-1H-pyrrol-2-yl)prop-2-yn-1-ol has been synthesized for the first time by ethynylation of 1-methyl-1H-pyrrole-2-carbaldehyde with acetylene in the superbasic system KOH-DMSO-H2O under atmospheric pressure.

Acetylene phosphorylation with elemental phosphorus in the KOH-DMSO system

Reaction of red phosphorus with acetylene in multiphase superbasic KOH-DMSO system has been studied. The phosphorylation of acetylene results in poly(divinylphosphinic acid).

Diastereoselective self-organization of acetylene and acetophenone molecules into 1-benzoyl-3-hydroxy-cyclopentene in the presence of potassium hydroxide

We have recently found that acetylene and alkyl aromatic and alkyl heteroaromatic ketones in the superbasic system KОН–DMSO (80С, 1 h) underwent instead of Favorskii reaction a unique selective tandem reaction leading in a single preparative stage to the formation of complex functionalized heterocyclic systems with a frontalin scaffold, 7-methylene-6,8dioxabicyclo[3.2.1]octanes in up to 86% yield [1]. Since frontalin and its analogs are well known insect pheromones [2, 3] and mammal hormones [4, 5], this easy stereoselective (a single diastereomer forms among many possible) and one-pot approach to their derivatives opens new opportunities for the development of their preparative chemistry. At the same time the yet unknown aspect of acetylene reactivity has been unexpectedly revealed: Its capability in the presence of strong bases to undergo self-assembly with the capture of suitable nucleophiles into complex difficultly available functionalized molecules often structurally close to naturally occurring substances. Here we preliminary report that at the systematic investigation of the above mentioned reaction by an example of acetophenone we have found an entirely new direction of self-assembly of two acetylene and two acetophenone molecules affording along with the expected 7-methylene-6,8-bicyclo[3.2.1]octane (I) also 1-benzoyl-3-hydroxycyclopentene (II), also in the form of a single diastereomer (Scheme 1). The preparative yield of structural isomers I and II was 43 and 46% respectively at the acetophenone conversion 46% (the conditions were not yet optimized).

A theoretical study of acetone reactions with acetylene and phenylacetylene in the KOH/DMSO superbasic system

A theoretical study of acetone reactions with acetylene and phenylacetylene in the KOH/DMSO superbasic system

Polymerization of N-vinylpyrroles: Recent achievements

The data on the polymerization of N-vinylpyrroles published for the most part during the past decade are systematized and summarized. Radical, cationic, and anionic polymerization of the mentioned monomers, which became easily accessible owing to the discovery and systematic development of their direct one-step synthesis from ketoximes and acetylene in the superbasic catalytic system KOH/DMSO (the Trofimov reaction), are discussed. Special attention is given to the physicochemical properties of the polymers (conductivity, paramagnetism, photosensitivity, and optical characteristics).

ChemInform Abstract: One‐Pot Synthesis of 3‐(E)‐Styrylpyrroles from (E)‐Styrylmethyl Ketoximes and Acetylene.

(E)-Styrylmethyl ketoximes react with acetylene in KOH/DMSO superbase system (90 °C, 1 h) to afford stereoselectively 3-(E)-styrylpyrroles.

A new synthesis of bicyclic N,O- and N,S-enaminals by the anionic cyclization of alk-4-ynals with amino alcohols and amino thiols

A reaction of alk-4-ynals with aliphatic amino alcohols or 2-aminoethanethiol in the system DMSO—KOH gives bicyclic N,O- and N,S-enaminals: 6-methylidenehexahydro-2H-pyrrolo[2,1-b][1,3]oxazines, 5-methylidenehexahydropyrrolo[2,1-b]oxazoles, or 5-methyl-idenehexahydropyrrolo[2,1-b]thiazoles. The reaction proceeds through the formation of equilibrium mixtures of the corresponding imines and monocyclic aminals with subsequent 5-exodig-cyclization catalyzed by the superbasic system DMSO-KOH.

ChemInform Abstract: Synthesis of [2‐(Methoxyaryl)‐1‐methylethyl]phosphinic Acids from Red Phosphorus and (Allyl)(methoxy)benzenes.

(Allyl)(methoxy)benzenes react with red phosphorus in the superbasic system KOH-DMSO in the presence of small amounts of water and hydroquinone (3 h, 130 °C) to regio- and chemoselectively give [2-(methoxyaryl)-1-methylethyl]phosphinic acids in preparative yields up to 52%. The reactions involve isomerization of allylbenzenes into (prop-1-enyl)benzenes.

ChemInform Abstract: Improved Method for the Synthesis of 1‐Vinylindole

Abstractbased on the vinylation of indole by acetylene in the superbase system KOH‐DMSO

One-pot synthesis of 3-(E)-styrylpyrroles from (E)-styrylmethyl ketoximes and acetylene

(E)-Styrylmethyl ketoximes react with acetylene in KOH/DMSO superbase system (90 °C, 1 h) to afford stereoselectively 3-(E)-styrylpyrroles.

Nucleophilic addition of phosphine to 4-chlorostyrenes in the KOH-DMSO system

In the superbasic system KOH-DMSO (H2O) at 60–75 °C (2–2.5 h, atmospheric pressure), 4-chlorostyrene and 4-chloro-α-methylstyrene add phosphine at the double bond to form 1: 1 and 2: 1 anti-Markovnikov adducts in 10–18% and 58–67% yields, respectively.

The “one pot” synthesis of 4,5-dihydrobenzo[g]indole and its 1-vinyl derivative from 1-tetralone, hydroxylamine, and dichloroethane in the system KOH-DMSO

4,5-Dihydrobenzo[g]indole and its 1-vinyl derivative were obtained from 1-tetralone, hydroxylamine, and dichloroethane in the superbasic system KOH-DMSO (140 °C, 3 h) in a total yield of 88%. The proposed method provides a fire-safe and explosion-proof approach to indole derivatives in demand.

ChemInform Abstract: The Direct Thiolation of Benzothiazole Catalyzed by Copper Complex in Superbase System.

AbstractThe process involves in situ formation of disulfides from aryl iodides and sulfur under superbase conditions.

One-pot microwave synthesis of tertiary phosphine sulfides directly from aromatic alkenes, elemental phosphorus and sulfur in KOH–DMSO system

Aromatic alkenes (vinylbenzene, 1-(tert-butyl)-4-vinylbenzene, 1-chloro-4-vinylbenzene) react with red phosphorus and elemental sulfur in the superbasic system KOH–DMSO(H2O) under microwave irradiation (600 W, 6–8 min, Ar) in the presence of hydroquinone to afford tris(2-phenylethyl)-, tris[2-(4-tBu-phenyl)ethyl]- and tris[2-(4-Cl-phenyl)ethyl]phosphine sulfides in 53%, 38% and 42% yield, respectively.

Propargyloxy- and allenyloxymethylferrocenes: Synthesis and oligomerization

Propargyloxymethylferrocene has been synthesized by the modified reaction of available N,N-dimethylaminomethylferrocene with propargyl alcohol in the presence of dichloroethane and NaOH, the yield reaching 99.6%. The rapid prototropic isomerization of propargyloxymethylferrocene in the superbase system t-BuOK/DMSO (room temperature, 4 min) leads to previously unknown allenyloxymethylferrocene in 80% yield. Preliminary cationic and radical polymerizations of both monomers have been studied and novel oligomers with the polyene chain and pendant ferrocenyl moieties containing soluble and insoluble fractions have been synthesized in 83–88% total yield. All the oligomers exhibit semiconducting and paramagnetic properties and stable up to 300–340 °C.

ChemInform Abstract: Improved Synthesis of Tertiary Propargyl Alcohols by the Favorskii Reaction of Alkyl Aryl (Hetaryl) Ketones with Acetylene.

AbstractTertiary propargyl alcohols bearing aryl or heteroaryl substituents are readily accessible from the corresponding ketones and acetylene under atmospheric pressure using a superbasic system.

Preparation and Characterization of Alkylethoxyethanesulfonate in Superbasic System KOH-DMSO

Alkylethoxyethanesulfonate is one kind of nonionic-anionic surfactant with a polyglycol ether chain and a sulfonic group at the end of the chain. It was synthesized in a new method by using fatty alcohol-polyoxyethylene ether MOA-3, thionyl chloride and sodium isethionate as raw materials, and then the intermediate chloridepolyglycol ether MOACl-3 reacted with sodium isethionate in a superbasic system KOH-DMSO.The structures of MOA-3,MOACl-3 and alkylethoxyethanesulfonate MOASO-3 were confirmed by their IR spectrums, and the saltresistance of MOASO-3 was studied. IR analysis results indicate the intermediate and product all have the same structure with the aim compound. The saltresistance results show that MOASO-3 is compatible with NaCl aqueous solutions, when the concentration of MOASO-3 is 0.2wt%, the surfactant-water solutions were clear and transparent up 0.6wt% NaCl.

The Direct Thiolation of Benzothiazole Catalyzed by Copper Complex in Superbase System

The copper-catalyzed direct thiolation of benzothiazole with iodobenzene and sulfur in superbase system under oxygen atmosphere is reported. The corresponding 2-thio-substituted benzothiazoles were formed in satisfactory yields.

Improved synthesis of tertiary propargyl alcohols by the Favorskii reaction of alkyl aryl (hetaryl) ketones with acetylene

Alkyl aryl (hetaryl) ketones react with acetylene under atmospheric pressure in the superbasic system KOH-EtOH-H2O-DMSO at 10–15°C (2 h) to give the corresponding tertiary propargyl alcohols in up to 91% yield. The procedure requires no large excess of KOH and low-boiling inflammable solvents, produces few wastes, and is safe and convenient on the laboratory scale; there are no limitations for its large-scale application.

Nucleophilic addition of methanol and methanethiol to acetylene in the superbasic system KOH-DMSO: a quantum chemical model

Cluster-continuum models (KOH·nDMSO, n = 1, 5) were used to model the superbasic system “alkali metal hydroxide-dimethyl sulfoxide” within the framework of MP2/6-311++G**/ and B3LYP/6-31G* methods. The KOH molecule surrounded by five DMSO molecules exists as “solvate-loosened” ion pair with elongated K-O distance. It is proposed to consider the “solvate-loosened” ion pair of potassium cation with hydroxide anion in the surroundings of five solvent molecules as the catalytic coordination sphere of the superbasic system KOH-DMSO. Methanol and methanethiol molecules can be incorporated with ease into the first coordination sphere of potassium cation to form methoxide and methanethiolate ions. The possibility of nucleophilic attack of methoxide and methanethiolate ions on acetylene molecule in the first coordination sphere of potassium cation was studied. The model reaction system C2H2-CH3OK-H2O with one DMSO molecule included explicitly to maintain the “solvate-loosened” [CH3O]−...K+ ion pair and additional inclusion of solvent effects within the framework of the IEFPCM continuum model is the most preferable for serial calculations.