No abstract

A series of P2-modified, orally active peptidic inhibitors of human neutrophil elastase (HNE) are reported. These pentafluoroethyl ketone-based inhibitors were designed using pentafluoroethyl ketone 1 as a model. Rational structural modifications were made at the P3, P2, and activating group (AG) portions of 1 based on structure-activity relationships (SAR) developed from in vitro (measured Ki) data and information provided by modeling studies that docked inhibitor 1 into the active site of HNE. The modeling-based design was corroborated with X-ray crystallographic analysis of the complex between 1 and porcine pancreatic elastase (PPE) and subsequently the complex between 1 and HNE.

Design modifications to the lead HIV-PR inhibitor 1 (MDL 73,669, Ki = 5 nM) have been postulated based on a computational model of the 1/HIV-PR complex. A novel macrocyclic inhibitor 8 (MDL 104,168) wherein the P1 and P3 side chains of the original acyclic inhibitor have been joined retains good biological activity (Ki = 20 nM). NMR analysis of the precursor alcohol (S)-7 shows the conformation of the cyclic region to be very similar to that observed in the enzyme-bound 8 as determined by the computational model. Consistency of the computational model with NMR data and in vacuo molecular dynamics simulations provide the basis for postulating further modifications of the cyclic inhibitor expected to optimize its interactions with HIV-PR.

No abstract

MDL 103371 is a N-methyl-D-aspartate (NMDA)-type glycine receptor antagonist for the potential treatment of stroke. Evaluation of five different synthetic routes, which included Stille, Suzuki, enol ether, Knoevenagel, and the Mukaiyama coupling reactions, revealed the Knoevenagel approach superior for preparing large quantities of drug substance for evaluation. The overall process utilized some classical chemistry. Fischer indole cyclization, followed by a Vilsmeier-Haack formylation and a Knoevenagel condensation gave immediate access into the proper carbon framework of the target molecule. A unique hydrogenation cataylst and solvent system for a nitro reduction, followed by a two step acid-base hydrolysis of a nitrile gave the crude product. Purification was accomplished by a potassium salt crystallization followed by a Schiff base formation to give MDL 103371 in nine steps in an overall yield of 38%.