4-(Dimethylamino)pyridine N-oxide (DMAPO): an effective nucleophilic catalyst in the peptide coupling reaction with 2-methyl-6-nitrobenzoic anhydride.

Various carboxamides or peptides were synthesized from the corresponding carboxylic acids and amines or alpha-amino acids in high yields by the catalysis of 4-(dimethylamino)pyridine N-oxide (DMAPO) with 2-methyl-6-nitrobenzoic anhydride (MNBA). Because the segment-coupling reaction of alpha-amino acids proceeds through the effective activation of the carboxylic acid moieties with DMAPO in the presence of tertiary amines under mild conditions, undesired racemization was hardly observed in the synthesis of oligopeptides such as Z-Gly-Phe-Val-OMe, Z-Phe-Val-Ala-OMe, and Bz-Val-Val-OMe.

Total synthesis of buergerinin F via effective construction of the asymmetric quaternary carbons using an enantioselective aldol reaction.

An efficient method for the synthesis of (+)-buergerinin F is established via the enantioselective aldol reaction of a tetra-substituted ketene silyl acetal with crotonaldehyde, followed by intramolecular Wacker-type ketalization.

Taxol derivatives are selective inhibitors of DNA polymerase alpha.

During screening for mammalian DNA polymerase inhibitors, we found and succeeded in isolating a potent inhibitor from a higher plant, Taxus cuspidate. The compound was unexpectedly determined to be taxinine, an intermediate of paclitaxel (taxol) metabolism. Taxinine was found to selectively inhibit DNA polymerase alpha (pol.