Resonance Structure of Azaindoles

[Abstract]Contribution of resonance structures of 7-methyl-7H-7-azaindole and 4-methyl-4H-4-azaindole was examined. It was concluded from multinuclear NMR and MO calculation studies that the nonpolarized 7-methyl-7H-7-azaindole or 4-methyl-4H-4-azaindole is the major contribution structure. However, they have much larger dipole moments than non-methylated azaindoles. The electronic natures of pyrrole ring and pyridin ring of the methylated azaindoles are exchanged compared with those of 7- and 4-azaindoles, and the directions of the dipole moments were reversed

Functionalization of Pyridines via Reissert-Henze Reaction

[Abstract] Reaction of Reissert-Henze salt with silver acetylide gave the pyridine ethynylated selectively at 2-position. 2-(Phenylethynyl)pyridines substituted 3-position with a carbonyl or masked carbonyl group were converted to various bicyclic pyridine derivatives by intramolecular cyclization. 3-Cyano-2-(phenylethynyl)pyridine was cyclized intramolecularly under acidic conditions to give the naphthyridine and pyranopyridine derivatives. 2-(Phenylethynyl)pyridine reacted with dimethyl acetylenedicarboxylate in the presence of a proton source to give indolizines having methoxycarbonyl groups at the 2- or 2,3-positions

Functionalization of 7-Azaindole

[Abstract]Functionalization of 7-azaindole utilizing Reissert-Henze type reaction was studied. It was found that the direct halogenation, cyanation, and thiocyanation of 7-azaindole proceeded regioselectively. In chlorination of 7-azaindole, the regioselectivity was controlled by chlorination reagents as well as acylation reagents. These functional groups could be chemically modified to useful substituents

Characteristic Reaction Mode of Cofactor PQQ toward Nucleophiles

[Abstract] The characteristic reaction mode of coenzyme PQQ toward nucleophiles such as alcohols, amines, and hydrazines are surveyed. The selectivity of addition position of nucleophiles to the carbonyl group of PQQ was affected by reaction conditions and substituents of nucleophiles. Reaction mechanisms were discussed