Kazuaki. Nakahashi

New potent enkephalin analogs containing trifluoromethylamino acid residues

Abstract A series of new methionine-enkephalin analogs containing trifluoronorvaline (TFNV) or trifluoronorleucine (TFNL) in place of Gly 2 or Gly 3 are synthesized. The new analogs bearing (D)-TFNV in place of Gly 2 exhibit ca. 100,000 times enhancement in in vivo analgesic activity in comparison with methionine-enkephalin. The in vitro binding assays for mu, delta and kappa receptors reveal that this enhancement is not based on the much stronger binding to these receptors, but mainly due to the extremely efficient inhibition of degradation by aminopeptidase(s).

Synthesis of novel chiral bisazetidines by the hydroalane reduction of bis-beta-lactams

Abstract A series of novel chiral bisazetidines in which two azetidine rings are either directly connected or coupled in tandem style, are synthesized in good yields by the hydroalane reduction of the corresponding bis-beta-lactame.

Prostaglandin analogs modified at the 10 and 11 positions

Abstract A simplified methodology for the building of prostaglandins substituted at the 10 and 11 positions is presented.