Conformationally Constrained ortho-Anilino Diaryl Ureas: Discovery of 1-(2-(1′-Neopentylspiro[indoline-3,4′-piperidine]-1-yl)phenyl)-3-(4-(trifluoromethoxy)phenyl)urea, a Potent, Selective, and Bioavailable P2Y₁ Antagonist

Abstract

Preclinical antithrombotic efficacy and bleeding models have demonstrated that P2Y1 antagonists are efficacious as antiplatelet agents and may offer a safety advantage over P2Y12 antagonists in terms of reduced bleeding liabilities. In this article, we describe the structural modification of the tert-butyl phenoxy portion of lead compound 1 and the subsequent discovery of a novel series of conformationally constrained ortho-anilino diaryl ureas. In particular, spiropiperidine indoline-substituted diaryl ureas are described as potent, orally bioavailable small-molecule P2Y1 antagonists with improved activity in functional assays and improved oral bioavailability in rats. Homology modeling and rat PK/PD studies on benchmark compound 3l will also be presented. Compound 3l was our first P2Y1 antagonist to demonstrate a robust oral antithrombotic effect with mild bleeding liability in the rat thrombosis and hemostasis models.

Two disparate ligand-binding sites in the human P2Y1 receptor

“…The benzene ring within the phenoxy group of BPTU wedges into a cavity between helices II and III, interacting with T103 2.56 , M123 3.24 , L126 3.27 and Q127 3.28 . The hydrophobic nature of this sub-pocket is consistent with previous studies that have shown that the lipophilicity of this aryl group of the ligand is important for binding affinity and in vitro functional activity 22 . Similar to the A106 2.59 W mutant, the T103 2.56 W mutation abolished the binding affinity of BPTU to P2Y 1 R, but did not affect the binding of 2MeSADP and MRS2500 (Extended Data Table 2).…”

“…However, if the pyridyl is substituted by a phenyl group, an extra hydrophobic contact with M123 3.24 may be introduced. This is supported by the fact that a corresponding phenyl derivative showed higher ligand binding affinity and antiplatelet activity 22 . A106 2.59 is unique to P2Y 1 among P2YRs; other subtypes have larger side chains at this position, which could sterically hinder binding of BPTU’s phenyl ring to this site, consistent with its P2Y 1 R selectivity.…”

“…The non-nucleotide ligand BPTU and other diarylurea P2Y 1 R antagonists have been recently introduced as novel antiplatelet agents 10,22,23 . Surprisingly, the P2Y 1 R-BPTU crystal structure reveals that instead of interacting within the 7TM helical bundle, BPTU binds to P2Y 1 R on the lipidic interface of the TM domain.…”

P2Y1‐like nucleotide receptors—Structures, molecular modeling, mutagenesis, and oligomerization

“…The urea derivative BPTU was identified as a noncompetitive P2Y 1 R‐selective antagonist, which binds in the transmembrane interface of TMI, II and III, where it exhibits aromatic and hydrophobic interactions . Interestingly previous studies had predicted a competitive binding mechanism for BPTU and its derivatives . The only hydrophilic interactions can be observed between the nitrogen atoms of the urea group and Leu102.…”

Oral Delivery of Highly Lipophilic Poorly Water-Soluble Drugs: Spray-Dried Dispersions to Improve Oral Absorption and Enable High-Dose Toxicology Studies of a P2Y1 Antagonist

“…BMS‐B (Fig. ) has been investigated as a potent P2Y1 antagonist to inhibit platelet aggregation and thrombus formation . The free base of BMS‐B is a white, amorphous powder with a molecular weight of 689 and p K a values of 7.6 and 9.7 (by spectrophotometric measurement).…”