Synthesis of 2,3-Dihydro-1-benzofuran-2-ylmethyltellanes

Russian Journal of General Chemistry - Tellurium tetrabromide readily reacted with 2-allylphenol at room temperature in acetonitrile to give previously unknown...     

2,3-Dihydro-7-benzofurancarbonsäuren

Summary The syntheses of a series of title compounds1 a–f bearing methyl groups in the heterocyclic part were described. Depending on the substitution pattern the Claisen rearrangement (path A) or the methodology of directed lithiations (path B) were used as the key steps.

Herrn o. Prof. Dr. Fritz Sauter mit den besten Wünschen zum 60. Geburtstag gewidmet     

Mass spectral fragmentation patterns of 2-methyl-, 2,3-methyl-, 2,3-dimethyl-, 2-aryl- and 3-phenylindole derivatives

The electron impact mass spectrometric fragmentation pathways for several 2-methyl-, 3-methyl-, 2,3-dimethyl-, 2-aryl- and 3-phenylindole derivatives were investigated. An interesting relationship between the substitution pattern in the framework of the indole derivatives and the fragmentation patterns was observed.     

New Condensation Products from 5,6-Dihydro-4-hydroxy-6-methyl-2-pyrone

We report the synthesis of new condensation products from 5,6-dihydro-4-hydroxy-6-methyl-2-pyrone, providing evidence for the particular reactivity of the 3 and 4 positions of this compound.     

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.     

Efficacious Entry Into Substituted 5,6-Dihydro-4-Hydroxy-2H-Pyran-2-Ones and 2,3-Dihydro-4H-Pyran-4-Ones Utilizing Ketonic Dianions

Methyl acetoacetate and 2,4-pentanedione dianions were condensed with aldehydes and ketones to afford a 1,3,5-trioxygenated carboskeleton. Intramolecular cyclization of the aldol adducts delivered the title compounds in good yield.     

2-p-Chlorphenyl-3-methyl-2,3-butandiol (Phenaglycodol)

Ohne Zusammenfassung     

Zur Bestimmung von 2-p-Chlorphenyl-3-methyl-2,3-butandiol

Ohne Zusammenfassung     

Synthesis of New Substituted 2,3-Dihydro-1,4-dioxin-2-ones and 1,4-Dioxan-2-ones

3-Alkyl-6-methyl-2,3-dihydro-1,4-dioxin-2-ones reacted with acetyl chloride in the presence of zinc(II) chloride to give the corresponding 3-alkyl-5-acetyl-6-methyl-2,3-dihydro-1,4-dioxin-2-ones. Oxidation of the latter with hydrogen peroxide in formic acid, followed by treatment with magnesium bromide, afforded 3-alkyl-6-methyl-1,4-dioxane-2,5-diones. Successive chlorination and dechlorination of 6-hydroxymethyl-1,4-dioxan-2-ones yielded 6-methylene-1,4-dioxan-2-ones.     

Synthesis of New Substituted 2,3-Dihydro-1,4-dioxin-2-ones and 1,4-Dioxan-2-ones

3-Alkyl-6-methyl-2,3-dihydro-1,4-dioxin-2-ones reacted with acetyl chloride in the presence of zinc(II) chloride to give 5-acetyl-3-alkyl-6-methyl-2,3-dihydro-1,4-dioxin-2-ones. Oxidation of the latter with hydrogen peroxide in formic acid, followed by treatment with magnesium bromide, afforded 3-alkyl-6-methyl-1,4-dioxane-2,5-diones. Chlorination of 6-hydroxymethyl-1,4-dioxan-2-ones with thionyl chloride and subsequent dehydrochlorination led to formation of 6-methylene-1,4-dioxan-2-ones.     

3-Phenylazo-4-methyl-2,3-dihydro-1,5-benzodiazepin-2-ones

The corresponding azo derivatives, which exist primarily in the azo form, are formed in the reaction of 2,3-dihydro-1,5-benzodiazepin-2-ones with diazonium cations. The hydrazone form of these compounds is possible in solutions of acids.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1558–1560, November, 1978.     

Rearrangement of 2-methyl-2,3-epoxypentane: a kinetic study

The kinetics of the rearrangement of 2-methyl-2,3-epoxypentane over ZnCl₂/pumice stone is reported. 2-Methyl-3-pentanone and 2,2-dimethylbutanal are formed in parallel reactions. The reaction scheme and kinetic equations best fitting the experimental data are given. This revised version was published online in August 2006 with corrections to the Cover Date.