The development of glycine transporter 1 (GlyT1) inhibitors may offer putative treatments for schizophrenia and other disorders associated with hypofunction of the glutaminergic N-methyl-d-aspartate ...(NMDA) receptor. Herein, we describe the synthesis and biological evaluation of a series of 3,4-disubstituted pyrrolidine sulfonamides as competitive GlyT1 inhibitors that arose from de novo scaffold design. Relationship of chemical structure to drug–drug interaction (DDI) and bioactivation was mechanistically investigated. Murine studies were strategically incorporated into the screening funnel to provide early assessments of in vivo target occupancy (TO) by ex vivo binding studies. Advanced compounds derived from iterative structure–activity relationship (SAR) studies possessed high potency in ex vivo binding studies and good brain penetration, promising preliminary in vivo efficacy, acceptable preclinical pharmacokinetics, and manageable DDI and bioactivation liabilities.
The glycine transporter 1 (GlyT1) has emerged as a key novel target for the treatment of schizophrenia. Herein, we report the synthesis and biological evaluation of aminotetralines and aminochromanes ...as novel classes of competitive GlyT1 inhibitors. Starting from a high-throughput screening hit, structure–activity relationship studies led first to the discovery of aminotetralines displaying high GlyT1 potency and selectivity, with favorable pharmacokinetic properties. Systematic investigations of various parameters (e.g., topological polar surface area, number of hydrogen bond donors) guided by ex vivo target occupancy evaluation resulted in lead compounds possessing favorable brain penetration properties as for (7S,8R)-27a. Further optimization revealed compounds with reduced efflux liabilities as for aminochromane 51b. In an in vivo efficacy model (7S,8R)-27a, dose-dependently reversed L-687,414 induced hyperlocomotion in mice with an ED50 of 0.8 mg/kg. All these results suggest (7S,8R)-27a and 51b as new GlyT1 inhibitors worthy of further profiling.
A large number (33) of human Fab fragments reacting with HIV-1 surface glycoprotein gp120 have been generated by selection from a combinatorial IgG1 kappa library displayed on the surface of phage. ...The library was prepared from a long term asymptomatic HIV-seropositive donor. Analysis of the sequences from these Fabs shows the heavy chains can be placed in groups, many of which contain intraclonal variants, almost certainly corresponding to chains used in vivo. Further variants can be accessed via chain shuffling experiments in which a given light chain is recombined with a library of heavy chains. Heavy chain promiscuity, i.e. the ability of heavy chains to pair with different light chains with retention of antigen binding, is dependent on the particular heavy chain considered and probably excludes the identification of in vivo light chain partners. The antibodies examined here are primarily to the CD4 binding site on gp120 and broadly reflect the serum profile of the donor. The antibodies show evidence of extensive somatic modification indicative of an antigen-driven response. The heavy chain CDR3 regions of the antibodies show a remarkably conserved extended length. A number also show strong sequence conservation in CDR3 against a background of considerable diversity in the rest of the VH gene supporting a central role for this region in antigen recognition.
Structural variation of the endothelin A-selective antagonist (S)-3-methoxy-2-(4,6-dimethoxypyrimidin-2-yloxy)-3,3-diphenylpropionic acid (LU 135252) led to analogues which retain ETA affinity but ...exhibit substantial ETB affinity as well. The most active derivative obtained is (S)-3-2-(3,4-dimethoxyphenyl)ethoxy-2-(4,6-dimethylpyrimidin-2-yloxy)-3,3-diphenylpropionic acid (LU 302872), which can be prepared in enantiomerically pure form in eight steps via an acid-catalyzed transetherification. It has a K i = 2.15 nM for binding to the ETA receptor and a K i = 4.75 nM for binding to the ETB receptor, is orally available, and antagonizes the big ET-induced blood pressure increase in rats and the big ET-induced bronchospasm in guinea pigs each time at a dose of 10 mg/kg.
Structural variation of the endothelin A-selective antagonist (S)-3-methoxy-2-(4,6-dimethoxypyrimidin-2-yloxy)-3, 3-diphenylpropionic acid (LU 135252) led to analogues which retain ET(A) affinity but ...exhibit substantial ET(B) affinity as well. The most active derivative obtained is (S)-3-2-(3, 4-dimethoxyphenyl)ethoxy-2-(4,6-dimethylpyrimidin-2-yloxy)- 3, 3-diphenylpropionic acid (LU 302872), which can be prepared in enantiomerically pure form in eight steps via an acid-catalyzed transetherification. It has a K(i) = 2.15 nM for binding to the ET(A) receptor and a K(i) = 4.75 nM for binding to the ET(B) receptor, is orally available, and antagonizes the big ET-induced blood pressure increase in rats and the big ET-induced bronchospasm in guinea pigs each time at a dose of 10 mg/kg.
