Selective C-3 lithiation of 2,3-dibromo- and 2,3-diiodo-1-methylindoles

Reaction of 2,3-dibromo-1-methylindole with tert-butyllithium at −78 °C followed by treatment with tropylium ion gave 2-bromo-3-cycloheptatrienyl-1-methylindole in a moderate yield, indicating that 2-bromo-3-lithio-1-methylindole would be involved as an intermediate instead of 3-bromo-2-lithio-1-methylindole. The structure of 2-bromo-3-cycloheptatrienyl-1-methylindole was unequivocally determined by a single X-ray analysis. 2,3-Diiodo-1-methylindole also gave a 3-lithio derivative exclusively.     

Synthesis of 5-R-3-Diphenylmethylene-2,3-dihydro-2-furanones from 5-Substituted 2,3-Dihydro-2,3-furandiones and Phenylbenzoyldiazomethane

3-Reactions of 5-aryl, 5-heteryl, and 5-styryl-2,3-dihydro-2,3-furandiones with phenylbenzoyldiazomethane gave rise to 5-substituted 3-dipenylmethylene-2,3-dihydro2-furanones. The possible intermediates and reaction products were investigated by semiempirical SCF MO LCAO method in AM1 approximation.     

Five-membered 2,3-dioxoheterocycles 3. The reaction of 5-aryl-2,3-dihydrofuran-2,3-diones with aliphatic and aromatic nitriles

On reaction of 5-aryl-2,3-dihydrofuran-2,3-diones with -aminoisobutyronitrile, o-aminobenzonitrile, and -anilinopropiononitrile, we obtained aroylpyruvic acid N-(1-methyl-1-cyanoethyl)-, N-(o-cyanophenyl)-, and N-phenyl-N-(cyanoethyl)-amides, respectively. On reaction of 5-aryl-2,3-dihydrofuran-2,3-diones with cyanoacetamide we obtained aroylacetic acid N-(cyanoacetyl)amides, while in the case of methyleneaminoacetonitrile and p-dimethylaminobenzonitrile we obtained (6-aryl-4-oxo-2,3-dihydro-1,3-oxazin-3-yl)acetonitriles and 2-(p-dimethylaminophenyl)-6-aryl-1,3-oxazine-4-ones, respectively.For Communication 2, see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 740–743, June, 1987.     

Synthesis of 2,3-dihydroxy-3-methylvaleric acid

Summary The synthesis of sodium 2,3-dihydroxy-3-methylvalerate (the 2,3-dihydroxy analog of isoleucine) is described.     

Synthesis of 3-Substituted Xylopyrnosides from 2,3-Anhydropentosides

Abstract

The facile regio- and stereoselective epoxide ring-opening of anhydropentosides described herein provides an attractive pathway to 3-substituted analogs of pentosides. Benzyl 2,3-anhydro-β-D-ribopyranoside (2) and benzyl 2,3-anhydro-β-L-ribopyranoside (7) were obtained from benzyl β-D-arabinopyranoside (1) and benzyl β-L-arabinopyranoside (3) respectively. The anhydropentosides were converted to the corresponding new 3-amino derivatives (8, 9, 10, and 11), alkoxy derivatives (12, 13, and 14), and deoxy sugar (15) in high yield. Every conversion was a one-step reaction of the anhydroglycoside with the appropriate nucleophile. Side-products due to epoxide migration were not observed.     

Reaction of 3-methyl-2,3-epoxysulfolane with alcohols

The corresponding dialkyl ethers of 3-methylsulfolane-2,3-diol are formed by the action of alcohols (methanol, ethanol, n-propyl alcohol, isopropyl alcohol, isobutyl alcohol, and n-octyl alcohol) on 3-methyl-2,3-epoxysulfolane in an acidic medium. The reaction proceeds through the intermediate formation of monoethers with subsequent etherification of the hydroxyl group by a second molecule of alcohol.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 613–615, May, 1979.     

Recyclization of 5-phenyl-2,3-dihydrofuran-2,3-dione to give 1,5-diphenylpyrazole-3-carboxylic acid

Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 846–847, June, 1990.     

Electronically promoted Payne rearrangement of 3-CF3-2,3-epoxyalcohols

[reaction: see text] Smooth and selective Payne rearrangement was achieved for the above types of epoxyalcohols with a CF(3) group so as to form thermodynamically more stable alkoxides, where the strongly electron-withdrawing nature of this moiety played a significantly important role and was proved to overcome increased steric instability of epoxides from syn-E to anti-Z isomers.     

Chemistry of 2-methylene-2,3-dihydro-3-pyranones

5-Aryl-2-acylmethylene-2,3-dihydro-3-furanones are recyclized by the action of hydrazine hydrate with the formation of 3-substituted 6-aryl-1H-4-pyridazinones, 3-alkoxycarbonylacetyl-5-aryl-4-methylpyrazoles, or 5-aryl-3-(3-oxo-2,3-dihydro-1H-5-pyrazolyl) pyrazoles, depending on the structure of the starting materials and the ratio of the reactants. The last-named are also obtained by the hydrazinolysis of the known 2-alkoxycarbonylmethyl-2-hydroxy-1,5-diaryl-2,3-dihydro-3-pyrrolones.For Communication 6, see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1031–1038, August, 1992.     

1-arylamino-3-phenyl-2,3-dihydro-2-indolones

-Chlorodiphenylacetyl chloride reacts with arylhydrazines to give 1-arylamino-3-phenyl-2,3-dihydro-2-indolones, which undergo acetylation at the nitrogen and oxygen and undergo benzoylation at the nitrogen atom.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 488–490, April, 1981.