Kinetic resolution of racemic (cyclohexyl)(geranyl)acetic acid

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2-(5-Bromo-2-furyl)quinoxaline and 3-(5-bromo-2-furyl)-2-quinoxalone

2-(5-Bromo-2-furyl)quinoxaline and 3-(5-bromo-2-furyl)-2-quinoxalone were obtained by the action of bromine on the corresponding quinoxaline derivatives and also by condensation of o-phenylenediamine with, respectively, (5-bromo-2-furyl)glyoxal or (5-bromo-2-furyl)glyoxylic acid esters.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 404–406, March, 1973.     

Enzymatic kinetic resolution of 1-(3′-furyl)-3-buten-1-ol and 2-(2′-furyl)-propan-1-ol

The enzymatic kinetic resolution of the racemic alcohols 1-(3′-furyl)-3-buten-1-ol (±)-1 and 2-(2′-furyl)propan-1-ol (±)-2 was investigated by screening a range of lipases and esterases for enantioselective transacylation, as well as for enantioselective hydrolysis. For both alcohols, lipase-catalyzed hydrolysis of the derived racemic acetate gave the best results for accessing the desired (S)-enantiomers. In the case of the secondary alcohol (±)-1, ASL turned out to be the optimum enzyme, whereas PPL was found to be superior in the case of the primary alcohol (±)-2. Additionally, an alternative access to (S)-2 via Oppolzer's camphor sultam methodology is described.     

Kinetic resolution of racemic secondary alcohols catalyzed by chiral diaminodiphosphine-Ir(I) complexes

Chiral diaminodiphosphine-Ir(I) complexes were found to efficiently catalyze enantioselective oxidation of racemic secondary alcohols in acetone. In the presence of base, oxidative kinetic resolution of the alcohols proceeded smoothly with excellent enantioselectivity (up to 98% ee) under mild conditions. [reaction: see text].     

Kinetic resolution of 5-(hydroxymethyl)-3-phenyl-2-isoxazoline by using the ‘low-temperature method’ with porous ceramic-immobilized lipase

A significant enhancement of the enantioselectivity (E value = 249) in the lipase-catalyzed resolution of a primary alcohol, racemic 5-(hydroxymethyl)-3-phenyl-2-isoxazoline (±)-1, was obtained by using the ‘low-temperature method’ (−60 °C) with porous ceramic-immobilized lipase (Amano PS-C II) and vinyl acetate in acetone.     

Synthesis and transformations of 2-(2-furyl)- and 2-[β-(2-furyl)vinyl] phenanthr [9,10]imidazoles

The corresponding 2-(2-furyl)- and 2-[-(2-furyl)vinyl] phenanthr[9,10]imidazoles were obtained by the condensation of 9,10 phenanthrenequinone with furfural, -(2-furyl)acrolein, and their 5-bromo and 5-nitro derivatives in the presence of ammonium acetate in glacial acetic acid. Their metallation, acetylation, nitration, and replacement of halogen by a nitro group were studied.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1014–1016, August, 1971.     

Kinetic resolution of 1-O-alkylglycerols by lipase

Pseudomonas sp. lipase was employed to resolve kinetically 1-O-alkylglycerols by a sequential diacylation process. Only low or moderate E-values were obtained, but at approximately 60% conversion enantiomerically pure monoacetates were obtained of the natural S-configuration for glyceryl ether lipids.     

Synthesis and transformations of 2-(2-furyl)- and 2-[β-(2-furyl)vinyl]imidazo[4,5-f]quinolines

The corresponding 2-(2-furyl)- and 2-[-(2-furyl)vinyl]imida zo[4,5-f]quinolines were obtained by condensation of 5,6-diaminoquinoline and 5-amino-6-rnethylaminoquinoline with furfural, furylacrolein, and their 5-bromo and 5-nitro derivatives and also with the hydrochlorides of imino esters of furancarboxylic and furylacrylic acids. Alkylation, acetylation, nitration, and substitution of the halogen in the furan ring by a nitro group were studied.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 440–442, April, 1973.     

A new chiral acid for the resolution of racemic bases : (s)-(-)-(2-phenylcarbamoyloxy)propionic acid (carbamalactic acid)

(S)-(?)-Carbamalactic acid is the phenylcarbamate derived from natural (S)-lactic acid. This new chiral reagent was efficiently used for the resolution of racemic bases such as α-methylbenzylamine, ephedrine and α-(l-naphthyl)ethylamine.     

The preparation of some 1-(2-furyl)-2-arylethylenes

Some 1-(2-furyl)-2-arylethylenes, where the furan nucleus is substituted in position 5 with a methyl or p-chlorophenyl group and where the aryl group is phenyl, p-nitrophenyl, α-naphthyl or β-naphthyl, have been prepared by the Perkin reaction and subsequent decarboxylation of the acid. The compounds 1-12 were prepared lor of photochemistry and photoelectron spectroscopy studies. Their geometrical configurations has been established by ¹H nmr and ir spectra.     

Synthesis and transformations of 2-(2-furyl)-and 2-[β-(2-furyl)vinyl]imidazo[4,5-b]phenazines

The corresponding 2-(2-furyl)- and 2-[-(2-furyl)vinyl]imidazo[4,5-b]phenazines were obtained by the condensation of 2,3-diaminophenazine with furfural and 2-furylacrolein and with their 5-bromo and 5-nitro derivatives. The phenazines were also synthesized by the reaction of 2-methylimidazo[4,5-b]phenazine with furfural and 5-bromo- and 5-nitrofurfural. The alkylation, acetylation, and nitration of the compounds obtained, as well as replacement of the halogen in the furan ring by a nitro group, were studied.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1425–1428, October, 1971.     

Potentiometric study on the complex equilibria between ni(ii) and mn(ii) and 3-(2-furyl)-2-mercaptopropenoic and 3-(2-furyl)-2-mercaptopropanoic acids

Complex formation between Ni(II), Co(II) and Mn(II) and 3-(2-furyl)-2-mercaptopropenoic and 3-(2-furyl)-2-mercaptopropanoic acids has been studied using glass electrode potentiometry. Ligand-metal ion mixtures in 10% (v/v) ethanol-water containing 0.1 mol dm^–3KNO₃ were titrated with potassium hydroxide. The e.m.f. data obtained have been analyzed using the linearization method, and initial estimates of protonation constants for the ligands and complex formation constants have been refined with the MINIQUAD program.     

Synthesis and properties of 2-(2-furyl)benzothiazole

The electrophilic reactions (nitration, bromination, hydroxymethylation, formylation, acylation) and radical substitution reactions (nitration, arylation) of 2-(2-furyl)benzothiazole have been studied. It was found that all of the reactions occur at position 5 of the furan ring. Only nitration in PPA gave the 5',6-dinitro derivative. Quantum-chemical calculation data for the electron density distribution in the neutral and protonated 2-(2-furyl)benzothiazole molecules are given. Dedicated to Boris Aleksandrovich Trofimov on his 70^th jubilee. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1331–1338, September, 2008.