Makoto Yamaye

Isopropylation of dibenzofuran over solid acid catalysts

Abstract The product compositions for the isopropylation of dibenzofuran over solid acid catalysts before and after reaching thermodynamic equilibrium (TE) were studied over H-silica-alumina and H-mordenite catalysts, and the shape selectivity of the latter was confirmed. For monoisopropylation over H-silica-alumina at 100–300°C for 2 h in an autoclave, the compositions of four isopropyldibenzofurans (MIPDBFs) before TE were in the following order: 2-MIPDBF=.4-MIPDBP > 62; 1-MIPDBF > 62; 3-MIPDBF. The compositions after TE were in the order: 4-MIPDBF > 62; 3-MIPDBF > 62; 2-MIPDBF > 62; 1-MIPDBF. Comparison between the two catalysts showed that the composition of 2-MIPDBF increased from 20–30% (over H-silica-alumina) to 48% (over H-mordenite). For diisopropylation under comparable conditions, the composition of 2,7-diisopropyldibenzofuran among its isomers also increased from 5–8 to 32%.

Preparation and Optical Resolution of a New Helical Lactone Carrying the 2,8-Dioxabicyclo[3.3.0]octane Ring System

A new overcrowded lactone (3) carrying the 2,8-dioxabicyclo[3.3.0]octane ring system was prepared by a simple treatment of tetraol (1) (prepared from 2,7-dihydroxynaphthalene and glyoxal) with 3,5-xylenol, and readily resolved into its enantiomers having a specific rotation of >800° (absolute value). A preliminary experiment demonstrated that 3 would be a promising resolving agent.

Stereochemistry of the products from the alkylation of 2-naphthol with glyoxal

Structural analyses of the products formed in the base-catalysed alkylation of 2-naphthol with glyoxal were performed by IR, 1H and 13C NMR spectroscopy and mass spectrometry. The final product, 7a,14c-dihydrobenzo[e]benzo[4,5]benzofuro[2,3-b]benzofuran (4), was determined to be in the cis rather than the trans form. MO calculations of the heats of formation and geometrical parameters also favour the cis form for 4. Two precursors of 4, 1,2-dihydronaphtho[2,1-b]furan-1,2-diol and 1-(2-hydroxy-1-naphthyl)naphtho[2,1-b]furan-2-ol, have also been analysed and their stereochemistry is discussed.

Preparation and Stereochemistry of the Isopropylidene Derivatives of 1,2‐Dihydronaphtho[2,1‐b]Furan‐1,2‐Diol and 1,2,9,10‐Tetrahydronaphtho[2,1‐b:7,8‐b′] Difuran‐1,2,9,10‐Tetraol in Comparison with the Corresponding Acetyl Derivatives

Abstract 1,2‐Dihydronaphtho[2,1‐b]furan‐1,2‐diol and 1,2,9,10‐tetrahydronaphtho[2,1‐b:7,8‐b′]difuran‐1,2,9,10‐tetraol were transformed into the corresponding isopropylidene derivatives, which were studied mainly by 1H NMR and chiral HPLC analyses in terms of a possible transformation mechanism and stereochemistry in comparison with their corresponding acetyl derivatives.

Base-catalysed Alkylation of 2,7-Naphthalenediol with Glyoxal. Isolation of Structurally Intriguing Products and their Stereochemistry

1,8-(2,5-Dihydroxy-1,4-dioxane-3,6-diyl)naphthalene-2,7-diol and 1,2,9,10-tetrahydronaphtho[2,1-b:7,8-b′]difuran-1,2,9,10-tetrol are prepared by reaction of 2,7-naphthalenediol with glyoxal, and their stereochemistry investigated mainly by NMR spectroscopy.

Coal deashing by alkali fusion

Deashing of Akabira coal was studied by NaOH or KOH fusion, followed by successive washing with water and hot water. Ash removal reached approximately 45% at 260 C and 80% at 380 C. Among major ash components, Fe[sub 2]O[sub 3] was least susceptible to removal, while SiO[sub 2] was removed by 55% even at 260 C. Pyridine extract yield reached maximum (56%) at 300 C and decreased at either higher or lower temperatures than 300 C.