Ken-ichi Tanji

A facile halogenation of some hydroxyheterocycles using triphenylphosphine and N-halosuccinimide

Abstract Some hydroxyheterocycles were halogenated to give the corresponding haloheterocycles using triphenylphosphine and N -halosuccinimide. In comparison with the usual method using phosphorus oxyhalide, the haloheterocycles were easily isolated.

Application of Phosphonium Salts to the Reactions of Various Kinds of Amides

The phosphonium salts 1 and 2 prepared from triphenylphosphine and N-halogenosuccinimide proved to be applicable to the conversion of amide compounds. Especially, halogenation of electron-deficient heteroaromatic alcohols with these reagents seems to be a convenient method compared to the halogenation with phosphorus oxyhalides.

Sorbicillinol, a Key Intermediate of Bisorbicillinoid Biosynthesis in Trichoderma sp. USF-2690

In the course of our screening program for free radical scavengers from Trichoderma sp. USF-2690, we found an unidentified metabolite (1) that appeared by the method used for HPLC analysis. Metabolite 1 gradually decreased with the production of bisorbicillinoids and was easily missed during the general isolation procedure. The LC-ESI-MS (negative) analysis for 1 gave m/z 247 as the (M-1)- ion peak. The hydrolysis of synthetic 6-O-acetylsorbicillinol (±-2) by 0.05 M KOH and acetylation of product 1 in an aqueous solution indicated that the structure of 1 was (6S)-4-(2,4-hexadienoyl)-3,6-dihydroxy-2,6-dimethyl-2,4-cyclohexadien-1-one, designated sorbicillinol, a quinol that has been postulated to be important in bisorbicillinoid biosynthesis.

Lithiation of 1H-pyrazolo[3,4-d]pyrimidine derivative using lithium alkanetellurolate

Abstract 4-Chloro-1-phenyl-1H-pyrazolo[3,4-d]pyrimidine was converted into alkyl 1-phenyl-1H-pyrazolo[3,4-d]pyrimidin-4-yl telluride, which was lithiated using alkyllithium followed by the reaction with electrophiles.

Solvent-free reaction using phosphonium salts : Chlorination of hydroxyheteroaromatics and dehydration of primary amides

Solvent-free chlorination of heteroaromatics using the phosphonium salt, prepared by reaction of triphenylphosphine with N-chlorosuccinimide, was accomplished by microwave-irradiation or heating to give the corresponding chloroheteroaromatics. Similarly, primary amides was converted into nitriles by this method.

The tellurium–lithium exchange reaction: selective functionalization of electron-deficient heteroaromatics

Abstract Electron-deficient heteroaromatic tellurides, which was obtained from the corresponding haloheteroaromatics, reacted selectively with n -butyllithium to give the lithio derivatives.

Palladium-catalyzed coupling reaction of haloheteroaromatic compounds in water

Palladium-catalyzed coupling reaction of π-deficient heteroaromatic halide in water was accomplished with excellent to good yields without any side reactions such as hydrolysis.

An improved method for chlorination of nitrogen-containing π-deficient heteroaromatics using triphenylphosphine and trichloroisocyanuric acid

Phosphorus compound prepared by reaction of triphenylphosphine with trichloroisocyanuric acid was found to be applied to chlorination of nitrogen-containing π-deficient heteroaromatics. As self-decomposition of the chlorinating reagent hardly proceeds, the reagent is more useful than phosphorus compound prepared by triphenylphosphine and N-chlorosuccinimide.

Purines. IX, Reaction of 9-phenyl-9H-purine-2-carbonitriles with Grignard reagents

The palladium-catalyzed cross-coupling reaction of 2- and 6-chloro-9-phenyl-9H-purines with potassium cyanide proceeded to give 9-phenyl-9H-purine-2- (3a-c) and -6-carbonitriles (4a-c). The conversion of the cyano group at the 2-position into the corresponding acyl groups was achieved by treatment of 3a,b with Grignard reagents

Oxidative magnesiation of halogenopyridines: introduction of electrophilic substituents to the pyridine moiety under the Barbier condition

Oxidative magnesiation of halogenopyridines was carried out using active magnesium prepared by the reduction of magnesium chloride, to give pyridinylmagnesium halides, which were treated with electrophiles to afford the corresponding pyridine derivatives.