Synthesis and kinetic studies of an amidine-containing phosphonofluoridate: a novel potent inhibitor of trypsin-like enzymes

Mast Cell Tryptase β as a Target in Allergic Inflammation: An Evolving Story

“…Among the investigated 12 trypsin-like serine proteases acrosin, trypsin, and tryptase are inhibited efficiently by biotinyl-Ser-Lys-Gly-Arg-CH 2 Cl (6) with second-order rate constants of 309,000, 148,000, and 111,000 M -1 s -1 , respectively [125]. Also diphenyl phosphonate esters and phosphonofluoridates derived from basic amino acids have been tested as covalent tryptase inhibitors [126,127]; among them Z-(4-AmPhGly) P (OPh)(F) (7) shows the highest reactivity with tryptase (k 2 /K i 40,000 M -1 s -1 ) [127].…”

Late-Stage Conversion of Diphenylphosphonate to Fluorophosphonate Probes for the Investigation of Serine Hydrolases

“…The first proposal reported suggests fluoride nucleophilic substitution at phosphorus produces monofluorinated intermediate 14 , which undergoes direct hydrolysis to 16 with loss of phenol (Murai et al, 2011). Given the documented susceptibility of alkyl-or aryl-fluorophosphonates to fluoride-displacing hydrolysis, however, any reaction sequence invoking the hydrolytic substitution of phenol over hydrogen fluoride must be cast into doubt (Ni and Powers, 1998; Waters and de Worms, 1949). Alternatively, an equilibrium process providing a low concentration of highly reactive difluoride intermediate 15 would be capable of producing 16 by hydrolysis.…”

“…To test our proposed mechanism, racemic, protected DPP Hpg analogue 13 was heated in an NMR tube containing excess NH 4 F and dry (ampoule) d 6 -DMSO (Figure S3 and S4). Monitoring of the reaction by 31 P-NMR spectroscopy revealed the formation of monofluorinated intermediate 14 , appearing as two sets of doublets ( 1 J P-F = 1135 Hz) (Ni and Powers, 1998) and consistent with the now stereogenic phosphorus center, followed by accumulation of product 16 as a single doublet ( 1 J P-F = 983 Hz) and an unknown species comparatively downfield present as two sets of doublets ( 1 J P-F = 1036 Hz). Overnight reaction exclusively produced 16 and the unknown coproduct without detection of difluoride 15 .…”

“…The reactivity of simple FPs, derived from the strongly polarized phosphorus–fluorine bond, has found use in chemical nerve agents (sarin, soman) and insecticides (diisopropylfluorophosphate-DFP) as general SH inhibitors marked by unfettered enzyme promiscuity. Early investigations integrating the FP warhead into simple amino acid analogues, however, demonstrated that modest selectivity for chymotrypsin, elastase, or trypsin-like enzymes was achievable depending on side-chain identity (Bartlett and Lamden, 1986; Lamden and Bartlett, 1983; Ni and Powers, 1998). Indeed, even largely aliphatic FP probes resembling substrates of diacylglycerol lipases or ghrelin esterases were found to selectively inhibit specific SHs with minimal off-target reaction (Bisogno et al, 2013; Eubanks et al, 2011).…”

Structure-based design, synthesis, and profiling of a β-tryptase inhibitor with a spiro-piperidineamide scaffold, benzylamine P1 group, and a substituted indole P4 group

“…9 The majority of research in the field reported in the last two decades has been largely focused on small synthetic organic inhibitors. [10][11][12][13][14][15][16][17][18][19][20] Inhibitors for trypsin-like serine proteases, of which b-tryptase is a member, can be generally divided into three categories: mechanism-based inhibitors, basic-P1 inhibitors, and non-basic P1 inhibitors. While the discovery for b-tryptase inhibitors has progressed beyond the least desirable mechanism-based category, the hunt for a non-basic P1 inhibitor has been fruitless so far.…”