Yasuo Kikugawa

N-methoxydiacetamide : a new selective acetylating agent

Abstract A simple and efficient method for the direct chemoselective acetylation of primary amines in the presence of alcohols or secondary amines using a new reagent N-methoxydiacetamide is described.

Chemistry of amine–boranes. Part 5. Reduction of oximes, O-acyloximes, and O-alkyl-oximes with pyridine–borane in acid

Oximes, O-acyl-oximes, and O-alkyl-oximes were reduced with pyridine–borane in the presence of acid to the corresponding hydroxylamine derivatives without over-reduction. Unstable O-acyl-hydroxylamines were directly synthesized for the first time from the corresponding O-acyl-oximes.

APPLICATION OF STABLE NITRENIUM IONS TO PREPARATIVE ORGANIC CHEMISTRY

Nitrenium ions and their related species are involved in many important chemical and biological processes. The present review will survey the recent progress of their utility in preparative organic chemistry.

Cyclization with nitrenium ions generated from N-methoxy- or N-allyloxy-N-chloroamides with anhydrous zinc acetate. Synthesis of N-hydroxy- and N-methoxynitrogen heterocyclic compounds

Electrophilic intramolecular aromatic substitution with an N-methoxy- or an N-allyloxy-acylnitrenium ion, generated by treatment of an N-methoxy- or an N-allyloxy-N-chloroamide with anhydrous zinc acetate in nitromethane, leads to formation of a nitrogen heterocyclic compound bearing an N-methoxy- or N-allyloxy group. The latter is readily converted to the corresponding N-hydroxy compound by palladium-catalyzed removal of the allyl group

A Convenient Synthesis of 1-Alkyl-1-phenylhydrazines from N -Aminophthalimide

Abstract N-Alkylaminophthalimides were synthesized by condensation of N-aminophthalimide with aldehydes, and subsequent reduction of the intermediate with pyridine-borane in acetic acid. N-Phenylation and removal of the phthalimide group gave 1-alkyl-1-phenylhydrazines in high yield.

A new intramolecular migration of the imino group of O-arylketoximes to the aryl group under the Beckmann condition

Abstract ZrCl 4 -mediated decomposition of O -arylketoximes in benzene leads to regioselective intramolecular migration of the imino group from the oxygen to the ortho position of the aryl group via electron-deficient nitrogen intermediates.

STEREOSELECTIVE SYNTHESIS OF CIS-5-ALKYL-(S)-PROLINES FROM (S)-PYROGLUTAMIC ACID VIA 5-ALKYL-5-HYDROXY-(S)-PROLINES

Introduction of alkyl groups with trialkylaluminums in the 5-position of the pyroglutamic ring system without ring opening and subsequent hydrogenation over Pt/C lead to exclusively cis-5-alkyl-(S)-prolines without epimerization of the chiral centre.

A Convenient N-Protection of Pyroglutamate Derivatives

Abstract Esters of pyroglutamic acid were N-protected by conventional protective groups (Z. Boc, and COOMe) in high yield, without racemization, using LiHMDS in THF at - 78 °C and ZCl, Boc2O, and ClCOOMe, respectively.

N-Phenylation of N-Arylaminophthalimides with Triphenylbismuth and Cupric Acetate: A Convenient Synthesis of 1-Aryl-1- Phenylhydrazines

Abstract Synthesis of 1-aryl-1-phenylhydrazines (2) from N-aryl-N-phenylaminophthalimides (1) which were synthesized by the phenylation of 1 with triphenylbismuth and cupric acetate is described.

Total synthesis of eupolauramine

Abstract A ten-step total synthesis of the title compound was accomplished in satisfactory yield. As a basis for the above synthesis, a facile preparation of 6-methoxybenzo[h]quinolines from the N-methoxyamide 8 was developed using the intramolecular trapping of a N-methoxy-N-acylnitrenium ion, the acid catalyzed regiospecific direct methoxylation, and the aromatization of dihydrocarbostyril moiety to quinoline moiety via thiolactam formation.