Discovery and optimization of (R)-prolinol-derived agonists of the Growth Hormone Secretagogue receptor (GHSR).

The discovery and optimization of a novel series of prolinol-derived GHSR agonists is described. This series emerged from a 11,520-member solid-phase library targeting the GPCR protein superfamily, and the rapid optimization of low micromolar hits into single-digit nanomolar leads can be attributed to the solid-phase synthesis of matrix libraries, which revealed multiple non-additive structure-activity relationships. In addition, the separation of potent diastereomers highlighted the influence of the alpha-methyl stereochemistry of the phenoxyacetamide sidechain on GHSR activity.

(D)-2-tert-Butoxycarbonylamino-5,5-difluoro-5-phenyl-pentanoic acid: synthesis and incorporation into the growth hormone secretagogues.

The first enantioselective synthesis of (D)-2-tert-butoxycarbonylamino-5,5-difluoro-5-phenyl-pentanoic acid 3 was achieved. The incorporation of the titled compound into growth hormone secretagogue (GHS) compounds resulted in new analogs 10 and 16, both of which had significantly increased in vitro potency. The compound 10 also showed improved in vivo efficacy as well as pharmacokinetic properties in rat models.

Tetrazole based amides as growth hormone secretagogues.

A novel series of N1 substituted tetrazole amides were prepared and showed to be potent growth hormone (GH) secretagogues. Among them, hydroxyl containing analog 31 displayed excellent in vivo activity by increasing plasma GH 10-fold in an anesthetized IV rat model.

Design and synthesis of tetrazole-based growth hormone secretagogue: the SAR studies of the O-benzyl serine side chain.

The structure-activity relationship of the O-benzyl serine side chain was investigated based on the tetrazole-based growth hormone secretagogue BMS-317180 (2). The ortho position of the benzyl moiety was found to be favorable for introduction of substituents. A series of ortho-substituted compounds were synthesized with improved in-vitro and in-vivo activity.