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G B Liang

Publications and source records attributed to G B Liang.

3 recordsLinked to original sources
PubMed2000

Synthesis and SAR of benzyl and phenoxymethylene oxadiazole benzenesulfonamides as selective beta3 adrenergic receptor agonist antiobesity agents.

Benzyl and phenoxymethylene substituted oxadiazoles are potent and orally bioavailable beta3 adrenergic receptor (AR) agonists. The 4-trifluormethoxy substituted 5-benzyl oxadiazole 5f has an EC50 of 8 nM in the beta3 AR agonist assay with 100-fold selectivity over beta1 and beta2 AR binding inhibition activity. Its oral bioavailability in dogs is 30 +/- 4%, with a half-life of 3.8 +/- 0.4 h. In the anesthetized rhesus, 5f evoked a dose-dependent glycerolemia (ED50Gly = 0.15 mg/kg). Under these conditions a heart rate increase of 15% was observed at a dose level of 10 mg/kg.

Adrenergic beta-3 Receptor Agonists↗
PubMed1992

Variations in the turn-forming characteristics of N-acyl proline units.

We have examined intramolecular hydrogen bonding in four homologous compounds, N-acetyl-, N-propionyl-, N-i-butyryl-, and N-pivaloyl-proline-methylamide, in methylene chloride, by means of 1H-nmr and ir measurements. At room temperature, the major trans conformer of MeCO-Pro-NHMe appears to be approximately 68% intramolecularly hydrogen bonded, the trans conformers of EtCO-Pro-NHMe and i-PrCO-Pro-NHMe are approximately 75% intramolecularly hydrogen bonded, and t-BuCO-Pro-NHMe is approximately 50% intramolecularly hydrogen bonded. Thus, the internally hydrogen-bonded state (C7 or gamma-turn) is significantly less populated for the N-pivaloyl compound than for the other three molecules in this series. Variable temperature measurements indicate that for each proline derivative there is very little enthalpic difference between the intramolecularly hydrogen-bonded and nonhydrogen bonded states of the trans rotamer. Changing the N-terminal acyl group also affects intramolecular hydrogen bonding (including beta-turn formation) in end-blocked Pro-Gly dipeptides.

Dipeptides↗