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Screening of our chemical library using a rat corticotropin-releasing hormone (CRH) receptor assay led to the discovery that 2-anilinopyrimidine 15-1 weakly displaced [125I]-0-Tyr-oCRH from rat frontal cortex homogenates when compared to the known peptide antagonist alpha-helical CRH(9-41) (Ki = 5700 nM vs 1 nM). Furthermore, 15-1 weakly inhibited CRH-stimulated adenylate cyclase activity in the same tissue, but it was less potent than alpha-helical CRH(9-41) (IC50 = 20 000 nM vs 250 nM). Systematic structure-activity relationship studies, using the cloned human CRH1 receptor assay, defined the pharmacophore for optimal binding to hCRH1 receptors. Several high-affinity 2-anilinopyrimidines and -triazines were discovered, some of which had superior pharmacokinetic profiles in the rat. This paper describes the structure-activity studies which improved hCRH1 receptor binding affinity and pharmacokinetic parameters in the rat. Compound 28-17 (mean hCRH1 Ki = 32 nM) had a significantly improved pharmacokinetic profile in the rat (19% oral bioavailability at 30 mg/kg) as well as in the dog (20% oral bioavailability at 5 mg/kg) relative to the early lead structures.

Vinylsulfoxyallenes (3a-c) are prepared from propargylic alcohols in 47-65% yield. Vinylsulfoxyallenes undergo facile [4+2] cycloadditions with methyl triazolidenedione (MTAD) and singlet oxygen to afford phe- nylsulfinylpyridazines and spirocyclic phenylsulfinyl-2H-pyran-3(6H)- ones in excellent yields (60-90%). Spirocyclic phenylsulfinyl-2H-py- ran-3(6H)-ones are oxidized to the corresponding phenylsulfones with peracid or can be epoxidized with basic hydrogen peroxide. Spirocyclic pyranone formation is thought to proceed via the rearrangement of a labile cyclic peroxide intermediate (14)

Several β-sulfoxy-substituted acetylenic carbinols were prepared by the addition of thiyl radicals and oxygen to conjugated enynes. The products obtained are derived from thiyl radical attack at the olefinic bond to generate a propargylic radical. Capture of this radical by oxygen followed by hydrogen transfer from thiophenol gives a hydroperoxide intermediate, which undergoes oxygen transfer by both intra- and intermolecular pathways. The resultant β-phenylsulfinyl propargylic alcohols proved to be versatile intermediates for the preparation of several different classes of compounds. The [2,3]-sigmatropic sulfinate to sulfoxide rearrangement was found to give 1,4-bis(phenylsulfonyl)1,3-butadienes, α,β-unsaturated phenylsulfoxy ketones, and β-phenylsulfonyl α-allenic sulfoxides