208516-93-2Relevant academic research and scientific papers
Synthesis and evaluation of 2-(2-fluoro-4-hydroxymethyl-5-methoxy-phenoxy) acetic acid as a linker in solid-phase synthesis monitored by gel-phase 19F NMR spectroscopy
Wallner, Fredrik K.,Spjut, Sara,Bostroem, Dan,Elofsson, Mikael
, p. 2464 - 2471 (2007)
Gel-phase 19F NMR spectroscopy is a useful monitoring technique for solid-phase organic chemistry due to the high information content it delivers and swift acquisition times, using standard NMR spectrometers. This paper describes the synthesis of the novel linker 2-(2-fluoro-4-hydroxymethyl-5- methoxy-phenoxy)acetic acid in 29% yield over seven steps, using nucleophilic aromatic substitutions on 2,4,5-trifluorobenzonitrile as key steps. Following standard solid-phase synthesis a peptide could be cleaved from the linker using 20% TFA in CH2Cl2 in 30 minutes, in contrast to a previously described monoalkoxy linker that requires 90% TFA in water at elevated temperature. A resin-bound peptide could be successfully glycosylated using only two equivalents of a thioglycoside donor, activated with N-iodosuccinimide and trifluoromethanesulfonic acid, and subsequent cleavage and deprotection gave the target glycopeptide. Direct glycosylation of the linker itself followed by mild acidic cleavage gave a fully protected hemiacetal for further chemical manipulation. This journal is The Royal Society of Chemistry.
Development of orally active oxytocin antagonists: Studies on 1-(1-{4- [1-(2-methyl-1-oxidopyridin-3-ylmethyl)piperidin-4-yloxy].2methoxybenzoyl}- 4-yl)-1,4-dihydrobenz[d][1,3]oxazin-2-one (L-372,662) and related pyridines
Bell, Ian M.,Erb, Jill M.,Freidinger, Roger M.,Gallicchio, Steven N.,Guare, James P.,Guidotti, Maribeth T.,Halpin, Rita A.,Hobbs, Doug W.,Homnick, Carl F.,Kuo, Michelle S.,Lis, Edward V.,Mathre, David J.,Michelson, Stuart R.,Pawluczy, Joseph M.,Pettibone, Douglas J.,Reiss, Duane R.,Vickers, Stanley,Williams, Peter D.,Woyden, Carla J.
, p. 2146 - 2163 (2007/10/03)
The previously reported oxytocin antagonist L-371,257 (2) has been modified at its acetylpiperidine terminus to incorporate various pyridine N- oxide groups. This modification has led to the identification of compounds with improved pharmacokinetics and excellent oral bioavailability. The pyridine N-oxide series is exemplified by L-372,662 (30), which possessed good potency in vitro (Ki = 4.1 nM, cloned human oxytocin receptor) and in vivo (intravenous AD50 = 0.71 mg/kg in the rat), excellent oral bioavailability (90% in the rat, 96% in the dog), good aqueous solubility (>8.5 mg/mL at pH 5.2) which should facilitate formulation for iv administration, and excellent selectivity against the human arginine vasopressin receptors. Incorporation of a 5-fluoro substituent on the central benzoyl ring of this class of oxytocin antagonists enhanced in vitro and in vivo potency but was detrimental to the pharmacokinetic profiles of these compounds. Although lipophilic substitution around the pyridine ring of compound 30 gave higher affinity in vitro, such substituents were a metabolic liability and caused shortfalls in vivo. Two approaches to prevent this metabolism, addition of a cyclic constraint and incorporation of trifluoromethyl groups, were examined. The former approach was ineffective because of metabolic hydroxylation on the constrained ring system, whereas the latter showed improvement in plasma pharmacokinetics in some cases.
