Yoshinobu Tagawa

Improved Oxidation of Active Methyl Group of N-Heteroaromatic Compounds by Selenium Dioxide in the Presence of tert-Butyl Hydroperoxide

The oxidation of active methyl group of N-heteroaromatic compounds including both of bicyclic and monocyclic compounds using SeO 2 was considerably improved in the presence of tert-butyl hydroperoxde in dioxane to give the corresponding aldehyde or carboxylic acid in the moderate to good yields. The present oxidation proceeds more mildly and more selectively to form aldehyde rather than carboxylic acid, compared with conventional SeO 2 oxidation without tert-butyl hydroperoxide.

Improved convenient and environmentally benign synthesis of biological active benzimidazoles using activated carbon and molecular oxygen

The reaction of 1,2-phenylenediamine with a variety of aromatic aldehydes in xylenes gave the corresponding benzimidazole derivatives in good to excellent yields (82-93%) in the presence of dry activated carbon and bubbling molecular oxygen. The present reaction involves the simple procedure, easy workup and environmentally benign materials such as molecular oxygen and reusable activated carbon.

Nitrosation of 1-alkylisoquinolines and their N-oxides and configurational assignments of their oximes

Nitrosation of 1-methyl-, 1-ethylisoquinoline and their N-oxydes with alkyl nitrite was studied under various conditions, and the following three systemes, (t-BuONO and n-BuLi-t-BuOK in THF), were found to be generally effective for nitrosation of not only isoquinolines but also pyridine and quinoline derivatives

Amination and nitrosation of quinolines and their N-oxidxes

1-Ethylquinoline 1-oxide reacted with isopropyl nitrite and sodium amide in liquid ammonia to give 2-amino-4-ethylquinoline 1-oxude as the main product. Similar animation occurred also with lepidine 1-oxide and quinoline 1-oxide, but only the corresponding oximes were formed from reactions of 4-ethylquinoline and lepidine under the same conditions

Preparation and antibacterial activity of 3-methyl-1-p-substituted phenylpyrazole-5-thiol.

3‐Methyl‐1‐phenylpyrazole‐5‐thiol (3a) and its p‐nitro‐(5) and p‐fluorophenyl (8) derivatives were prepared as potential antimicrobial agents in relatively good yields. Compounds 3a and 8 showed good antibacterial activities against MRSA, S. aureus, S. epidermidis, E. faecalis, E. faecium, and S. pyogenes. Moreover, compound 3a also showed a synergistic effect with some aminoglycosides.

A novel reaction of benzoyl chloride adduct of aromatic N-oxide with carbonitrile via a carbene intermediate

Abstract A carbene intermediate is proposed as a reactive species in the base-induced reaction of benzoyl chloride adducts of pyridine and quinoline N-oxides with carbonitriles to give 2-pyridyl- and 2-quinolyl diacylamine as main products.

One‐Pot Synthesis of Tetrahydro‐2‐Methylidenefurans

Abstract Tetrahydro‐2‐methylidenefurans were prepared by the ring‐opening/recyclization reaction of 2‐(disubstituted amino)‐4,5‐dihydro‐3‐furancarbonitriles with dichloroacetyl chloride in the presence of potassium carbonate.

Elucidation of the reaction path for the nitrosation of 2- and 4-methylpyridine 1-oxides with alkyl nitrite in liquid ammonia

The reaction path for the nitrosation of 2- and 4-methylpyridine 1-oxides with alkyl nitrite in the presence of NaNH 2 in liquid NH 3 was elucidated experimentally, and theoretically by the use of a semiempirical molecular orbital method (PM3 method). In the case of the nitrosation of 4-methylpyridine 1-oxide at room temperature, only 4-pyridinecarboxamide 1-oxide was obtained, while at −33°C a thermodynamically unstable aldoxime, (Z)-4-pyridinecarbaldehyde 1-oxide oxime, which was easily transformed into E-form by heating, was obtained,while at−33°C a thermodynamically unstable aldoxime, (Z)-4-pyridinecarbaldehyde 1-oxide,which was easily transformedinto E-form by heating,was obtained.