Kenichi Washizuka

Discovery of a Novel Series of Biphenyl Benzoic Acid Derivatives as Potent and Selective Human β3-Adrenergic Receptor Agonists with Good Oral Bioavailability. Part I

A novel class of biphenyl analogues containing a benzoic acid moiety based on lead compound 8i have been identified as potent and selective human beta 3 adrenergic receptor (beta 3-AR) agonists with good oral bioavailability and long plasma half-life. After further substituent effects were investigated at the terminal phenyl ring of lead compound 8i, we have discovered that more lipophilic substitution at the R position improved potency and selectivity. As a result of these studies, 10a and 10e were identified as the leading candidates with the best balance of potency, selectivity, and pharmacokinetic profiles. In addition, compounds 10a and 10e were evaluated to be efficacious for a carbachol-induced increase of intravesical pressure, such as an overactive bladder model in anesthetized dogs. This represents the first demonstrated result dealing with beta 3-AR agonists.

Discovery of a Novel Series of Benzoic Acid Derivatives as Potent and Selective Human β3 Adrenergic Receptor Agonists with Good Oral Bioavailability. 3. Phenylethanolaminotetraline (PEAT) Skeleton Containing Biphenyl or Biphenyl Ether Moiety

We designed a series of benzoic acid derivatives containing the biphenyl ether or biphenyl template on the RHS and a phenylethanolaminotetraline (PEAT) skeleton, which was prepared by highly stereoselective synthesis, to generate two structurally different lead compounds ( 10c, 10m) with a good balance of potency, selectivity, and pharmacokinetic profile. Further optimization of the two lead compounds to improve potency led to several potential candidates (i.e., 11f, 11l, 11o, 12b). In particular, biphenyl analogue 12b exhibited an excellent balance of high potency (EC50 = 0.38 nM) for beta3, high selectivity over beta1 and beta2, and good pharmacokinetic properties in rats, dogs, and monkeys.

Discovery of Highly Potent and Selective Biphenylacylsulfonamide-Based β3-Adrenergic Receptor Agonists and Evaluation of Physical Properties as Potential Overactive Bladder Therapies: Part 5

As an extension of research conducted on beta(3)-adrenergic receptor agonists as potential drugs for treating overactive bladder (OAB), novel series containing an acylsulfonamide moiety instead of the carboxylic acid moiety were evaluated. These compounds have been identified as potent and selective human beta(3)-AR agonists with improved oral bioavailability compared to the previous series. Results of structure-activity relationship (SAR) studies and cassette dosing evaluation in dogs showed several analogues (namely, 6h, 6j, 6o, 7e, and 9e) to have an excellent balance of in vitro potency and selectivity, pharmacokinetic (PK) profile, and an in vivo OAB model. Here we examined the relaxation response in dog detrusor muscle strips to a KCl induced tonic concentration. Results showed that the potency of in vitro relaxation response was not mirrored in the potency of the cAMP accumulation in CHO cell lines. Surprisingly, the EC(50) values of 6e and 7e found to induce relaxation of isolated bladder strips were over 50-fold higher than the cAMP accumulation in cell line. In general, increased lipophilicity led to decreased potency for the bladder relaxation compared with cAMP accumulation in CHO cell lines, indicating that lipophilicity is crucial for OAB drug candidates to improve beta(3) activity.

Discovery of highly potent and selective biphenylacylsulfonamide-based β3-adrenergic receptor agonists and molecular modeling based on the solved X-ray structure of the β2-adrenergic receptor: Part 6

As an extension of research, we have investigated modification of left-hand side (LHS) of biphenyl analogues containing an acylsulfonamide moiety in the development of potent and selective human beta(3)-adrenergic receptor (AR) agonists. Result of structure-activity relationships (SAR) and cassette-dosing evaluation in dogs showed that the hydroxynorephedrine analogue 16 had an excellent balance of in vitro and in vivo potency with pharmacokinetic profiles. In addition, to facilitate structure-based drug design (SBDD), we also have performed a docking study of biphenyl analogues based on the X-ray structure of the beta(2)-adrenergic receptor.

Discovery of novel series of benzoic acid derivatives containing biphenyl ether moiety as potent and selective human β3-adrenergic receptor agonists: Part IV

Identification and SAR study of novel series of beta(3)-AR agonists with benzoic acid are described. Conversion of ether linkage position of phenoxybenzoic acid derivative 2b led to compound 7b with moderate beta(3)-AR activity. Further modification in right, center and left parts of compound 7b was investigated to improve the beta(3)-AR potency and selectivity. Compounds 7g and 7k, with the bulky aliphatic-substituted group at 2-position of benzoic acid moiety, were identified as potent and selective beta(3)-AR agonists. In addition, in vivo efficacy of compounds 7g and 7k was exhibited on dog OAB model.

Synthesis and antibacterial activity of novel 4-pyrrolidinylthio carbapenems. Part III:

Abstract The synthesis and biological activity of a novel series of 2-alkyl-4-pyrrolidinylthio-β-methylcarbapenems containing a variety of cationic heteroaromatic substituents is described. As a result of these studies, we uncovered a relationship between in vitro antibacterial activity and the length of the alkyl spacer part, and discovered FR20950 ( 1c ) Download high-res image (74KB) Download full-size image Scheme 3 . Synthetic route to novel carbapenems. Reagents and conditions: (i) NaOMe, MeOH, (or TFA, Et 3 SiH), then 24 , i Pr 2 EtN, DMAC, MeCN; (ii) MeI, Me 2 CO or THF; (iii) ICH 2 CONH 2 , Me 2 CO; (iv) I(CH 2 ) 3 NHAoc, DMF; (v) MeOTf, CH 2 Cl 2 ; (vi) FSO 3 Me, CH 2 Cl 2 ; (vii) Pd(PPh 3 ) 4 , PPh 3 , THF–EtOH, n Bu 3 SnH or morpholine; (viii) Pd(OH) 2 -C, H 2 , THF–phosphate buffer (pH 6.5). , containing a two methylene spacer moiety and an imidazolio group, which possesses a balanced spectrum of antibacterial activity, including Pseudomonas aeruginosa and Methicillin-resistant Staphylococcus aureus (MRSA). Furthermore, FR20950 exhibited excellent urinary recovery, and comparable stability against renal dehydropeptidase-I (DHP-I) to Biapenem. DHP-I stability could be improved by introduction of a substituent on to the imidazole ring.