Design and synthesis of a highly selective EP2-receptor agonist.

EP2-receptor selective agonist 3 was identified by the structural hybridization of butaprost 1a and PGE(2) 2a. Based on this information, a chemically more stabilized 4 was discovered as another highly selective EP2-receptor agonist, iv administration of which to anesthetized rats suppressed uterine motility, while PGE(2) 2a stimulated uterine motility.     

Design and synthesis of a highly selective EP4-receptor agonist. Part 1: 3,7-dithiaPG derivatives with high selectivity.

A series of 3,7-dithiaPGE(1) analogues 3, 4, 11, 16 and 19 were identified as highly selective EP4-receptor agonists starting from the chemical modification of 7-thiaPGE(1) analogue 1. EP4-receptor selectivity and agonist activity were maximized in 3 and 4.     

Design and synthesis of a highly selective EP4-receptor agonist. Part 2: 5-thia and 9beta-haloPG derivatives with improved stability.

Further chemical modification to identify more chemically stabilized EP4-receptor selective agonists was continued. As a result, a further two EP4-receptor selective agonists 5-thiaPGE(1) 2a, 10 and 9beta-chloroPGF(2) analogue 11 were discovered.     

Design and synthesis of a selective EP4-receptor agonist. Part 2: 3,7-dithiaPGE1 derivatives with high selectivity

To identify new highly selective EP4-agonists, further modification of the 16-phenyl moiety of 1 was continued. 16-(3-methoxymethyl)phenyl derivatives 13-(6q) and 16-(3-ethoxymethyl)phenyl derivatives 13-(7e) showed more selectivity and potent agonist activity than 1. 16-(3-methyl-4-hydroxy)phenyl derivative 18-(14e) demonstrated excellent subtype selectivity, while both its receptor affinity and agonist activity were less potent than those of 13-(6q). Structure-activity relationships (SARs) are also discussed.     

Design and synthesis of a selective EP4-receptor agonist. Part 1: discovery of 3,7-dithiaPGE1 derivatives and identification of their omega chains

Improvement of EP4-receptor selectivity and the agonist activity by introduction of heteroatoms into the alpha chain of PGE1 was investigated. Among the compounds tested, 3,7-dithiaPGE1 4a exhibited good EP4-receptor selectivity and agonist activity. Further modification of the omega chain of 3,7-dithiaPGE1 was performed to improve EP4-receptor selectivity and agonist activity. Of the compounds produced, 16-phenyl-omega-tetranor-3,7-dithiaPGE1 4p possessing moderate EP4-receptor selectivity and agonist activity, was identified as a new chemical lead for further optimization by modification of the aromatic moiety.     

Synthesis and evaluation of a gamma-lactam as a highly selective EP2 and EP4 receptor agonist

Gamma-lactam analogs (2) of EP(4) receptor agonists were identified by substitution of the pyrazolidinone ring (1) with a pyrrolidinone ring. Several compounds (such as 2a, 2h) with high potency, selectivity and acceptable PK profiles were discovered. These were assessed in animal models of ovulation induction and bronchoconstriction.     

Design and synthesis of a selective EP4-receptor agonist. Part 3: 16-phenyl-5-thiaPGE(1) and 9-beta-halo derivatives with improved stability

To identify a new selective EP4-agonist with improved chemical stability, further chemical modification of those reported previously was continued. We focused our attention on chemical modification of the alpha chain of 3,7-dithiaPGE(1) and selected 5-thiaPGE(1) as a new chemical lead. Introduction of an optimized omega chain to the 5-thiaPG skeleton afforded m-methoxymethyl derivative 33a, which showed the most potent EP4-receptor agonist activity and good subtype-selectivity both in vitro and in vivo. 9beta-HaloPGF derivatives were also synthesized and biologically evaluated in an attempt to block self-degradation of the beta-hydroxyketone moiety. Among these series, and 39b showed potent agonist activity and good subtype-selectivity. Structure-activity relationships (SARs) are also discussed.     

Development of a highly selective EP2-receptor agonist. Part 1: identification of 16-hydroxy-17,17-trimethylene PGE2 derivatives

Design and synthesis of an EP2-receptor selective agonist began with the chemical modification of alpha- and omega-chains of butaprost 1a, which exhibits an affinity for the IP-receptor. Two series of prostaglandin (PG) analogues with a 16-hydroxy-17,17-trimethylene moiety as an omega-chain were identified. Among those tested, 4a,b,e,f,h and 6a,b,e,f,h were found to be highly selective EP2-receptor agonists. Structure-activity relationships are discussed.     

Development of a highly selective EP2-receptor agonist. Part 2: identification of 16-hydroxy-17,17-trimethylene 9beta-chloro PGF derivatives

Further chemical modification of 1a and 2 was undertaken to identify a more chemically stable selective EP2-receptor agonist for development as a clinical candidate. 9beta-chloro PG analogues 4a-e and 5a, c-e were found to be potent and selective EP2-receptor agonists. Among them, the compound 4aLy, which is a chemically stabilized lysine salt of 4a, exhibited an excellent profile both in biological activities and physicochemical properties. The agonist 4aLy was found to suppress uterine motility in anesthetized pregnant rats, while PGE2 stimulated uterine motility. Structure-activity relationships (SARs) are discussed.     

The synthesis and biological activity of a highly selective adenosine A2a receptor agonist

Three novel nucleosides 1, 2, and 3 were prepared that contained side chains at the 2-position of adenosine. Compound 1 was shown to be the most selective A2a receptor agonist reported to date having an A1/A2 ratio of 2400. In addition, compound 1 was shown to reduce blood pressure in rats and dogs with only minimal effects on heart rate.     

Efficient synthesis of a novel m-phenylene derivative as a selective EP4 agonist inducing follicular growth and maturation in the ovary

An efficient and straightforward synthesis of a novel m-phenylene derivative has been developed. The optically pure dibromo compound was selected as a starting material. Through a protocol involving the Prins reaction and two steps of the Horner–Wadsworth–Emmons reaction, the basic skeleton was constructed with appropriate alpha and omega side chains. The compound proved to be a highly selective EP₄ agonist and a possible drug candidate for maturation of the uterine cervix.     

Salvinorin A: a novel and highly selective kappa-opioid receptor agonist

kappa-opioid receptors (KORs) represent the principal site of action of dynorphin and related neuropeptides. Recently, Salvinorin A--a naturally occurring neoclerodane diterpene hallucinogen was identified to be a highly selective KOR agonist. In this brief review we summarize the known chemistry, pharmacology and biology of salvinorin A. Because salvinorin A profoundly alters human consciousness and perception, a study of how salvinorin A exerts its actions on KORs may yield novel insights into the molecular and cellular basis of uniquely human higher cortical functions.     

Discovery, synthesis, and biological evaluation of novel pyrrole derivatives as highly selective potassium-competitive acid blockers

To discover a gastric antisecretory agent more potent than existing proton pump inhibitors, novel pyrrole derivatives were synthesized, and their H(+),K(+)-ATPase inhibitory activities and inhibitory action on histamine-stimulated gastric acid secretion in rats were evaluated. Among the compounds synthesized, compound 17a exhibited selective and potent H(+),K(+)-ATPase inhibitory activity through reversible and K(+)-competitive ionic binding; furthermore, compound 17c exhibited potent inhibitory action on histamine-stimulated gastric acid secretion in rats and Heidenhain pouch dogs.     

Design, synthesis, and biological evaluation of novel analogues of archazolid: a highly potent simplified V-ATPase inhibitor

Novel analogues of the V-ATPase inhibitors archazolid A and B with modifications of the free hydroxyl groups and the side chain were designed by molecular modeling, synthesized by derivatization of the parent natural product and evaluated for V-ATPase inhibition and growth inhibition of murine connective tissue cells.     

Discovery of a novel EP2/EP4 dual agonist with high subtype-selectivity

A series of γ-lactam prostaglandin E(1) analogs bearing a 16-phenyl moiety in the ω-chain and aryl moiety in the α-chain were synthesized and biologically evaluated. Among the tested compounds, γ-lactam PGE analog 3 designed as a structural hybrid of 1 and 2 was discovered as the most optimized EP2/EP4 dual agonist with excellent subtype-selectivity (K(i) values: mEP2=9.3 nM, mEP4=0.41 nM). A structure-activity relationship study is presented.     

Design, synthesis and biological evaluation of selective boron-containing thrombin inhibitors.

Based on the structural comparison of the S-1 pocket in different trypsin-like serine proteases, a series of Boc-D-trimethylsilylalanine-proline-boro-X pinanediol derivatives, with boro-X being different amino boronic acids, have been synthesised as inhibitors of thrombin. The influence of hydrogen donor/acceptor properties of different residues in the P-1 side chain of these inhibitors on the selectivity profile has been investigated. This study confirmed the structure-based working hypothesis: The hydrophobic/hydrophilic character of amino acid residues 190 and 213 in the neighbourhood of Asp 189 in the S-1 pocket of thrombin (Ala/Val), trypsin (Ser/Val) and plasmin (Ser/Thr) define the specificity for the interaction with different P-1 residues of the inhibitors. Many of the synthesised compounds demonstrate potent antithrombin activity with Boc-D-trimethylsilylalanine-proline-boro-methoxypropylglycine++ + pinanediol (9) being the most selective thrombin inhibitor of this series.     

Discovery of a potent and selective agonist of the prostaglandin EP4 receptor

Analogues of PGE(2) wherein the hydroxycyclopentanone ring has been replaced by a lactam have been prepared and evaluated as ligands for the EP(4) receptor. An optimized compound (19a) shows high potency and agonist efficacy at the EP(4) receptor and is highly selective over the other seven known prostaglandin receptors.     

Discovery, synthesis and biological evaluation of isoquinolones as novel and highly selective JNK inhibitors (2)

3-Metoxycarbonyl isoquinolone derivative 1 has been identified as a potent JNK inhibitor and significantly inhibited cardiac hypertrophy in a rat pressure-overload model. Herein, a series of isoquinolones with an imidazolylmethyl or a pyrazolylmethyl group at the 2-position were designed based on X-ray crystallographic analysis of the complex between the isoquinolone compound and JNK3, as wells as the relationship between compound lipophilicity (logD) and activity in a cell-based assay. The compounds prepared showed potent JNK1 inhibitory activities in a cell-based assay. Among them the isoquinolone derivative possessing 5-[(cyclopropylamino)carbonyl]-1-methyl-1H-pyrazole (16e) exhibited significant anti-hypertrophic activity at doses of more than 1mg/kg (po) in a pressure-overload model.     

Discovery, synthesis and biological evaluation of isoquinolones as novel and highly selective JNK inhibitors (1)

A novel series of 4-phenylisoquinolones were synthesized and evaluated as c-Jun N-terminal kinase (JNK) inhibitors. Initial modification at the 2- and 3-positions of the isoquinolone ring of hit compound 4, identified from high-throughput screening, led to the lead compound 6b. The optimization was carried out using a JNK1-binding model of 6b and several compounds exhibited potent JNK inhibition. Among them, 11g significantly inhibited cardiac hypertrophy in rat pressure-overload models without affecting blood pressure and the concept of JNK inhibitors as novel therapeutic agents for heart failure was confirmed.     

Design,synthesis and biological evaluation of novel indole-xanthendione hybrids as selective estrogen receptor modulators

Ground breaking clinical therapeutic advances in the treatment of breast cancer (BC) is the introduction of selective estrogen receptor modulators (SERMs). We have expeditiously designed and synthesized indole-xanthendione hybrids by coalescing the indole nucleus with xanthendione. All the compounds were first screened for anti-proliferative activity, cytotoxicity and ER-α binding affinity by utilizing ER-α dominant T47D BC cell lines, PBMCs and ER-α competitor assay kit. From this study, two representative compounds 6e and 6f showing most promising activity were advanced for gene expression studies for targeting ER-α. Cell imaging experiment undoubtedly indicate that both the compounds were able to cross cellular bio membrane and accumulate thus instigating cytotoxicity. RT-PCR and Western blotting experiments further strengthened that both compounds altered the expression of mRNA and receptor protein of ER-α, thereby forestalling downstream transactivation and signalling pathway in T47D cells line. Structural investigation from induced fit simulation study suggest that indole moiety of the compounds 6e and 6f helps in the anchoring of the xanthendione moiety in the hydrophobic region of the cavity thus enabling the compound to bind in antagonistic conformation similar to bazedoxifene by extensive hydrogen bonding and Van der Waals forces. All these finding collectively imply that compound 6e and 6f represents a novel potent ER-α antagonist and in the development of SERMs for the management of BC.