Synthesis and Biological Activity of N-Sulfonylphosphoramidates:  Probing the Electrostatic Preferences of Alkaline Phosphatase

Abstract

N-Sulfonylphosphoramidates have been synthesized to investigate the electrostatic requirements for binding to alkaline phosphatase. Alkyl- and aryl N-benzylated sulfonamides were phosphorylated with bromophosphates or synthesized via phosphoramidite chemistry in moderate yields (44-77%.) The resulting tribenzylated N-sulfonylphosphoramidates may be deprotected in one step to give the free acids in quantitative yields. Physical data of N-sulfonylphosphoramidates, including pK(a)'s and stability toward hydrolysis, were determined. Inhibition data suggests that AP does not bind trianionic N-sulfonylphosphoramidates better than dianionic N-sulfonylphosphoramidates, although N-sulfonylphosphoramidates are bound tighter than N-phenylphosphoramidate. k(cat) for the hydrolysis of N-sulfonylphosphoramidates by bovine and E. coli alkaline phosphatases is 10-60% that of p-nitrophenyl phosphate.

Alkaline Phosphatase: A Reliable Endogenous Partner for Drug Delivery and Diagnostics

“…The shallow active site of ALP, however, makes it difficult to design selective and high-affinity inhibitors. [75,78] Discovery of potent and selective ALP inhibitors could help to better understand the role of ALPs in fundamental biological processes and unveil the secrets of life. As the enzyme active site possesses a high density of positive charges, the substrate electric charge, electron-withdrawing capability of the leaving group, pH, and pK a of the leaving group play important roles in binding efficacy and the overall catalytic/inhibitory activity.…”

Synthesis and Structural Aspects of N‐Triflylphosphoramides and Their Calcium Salts—Highly Acidic and Effective Brønsted Acids

“…In this context, it is well known that introduction of a triflate functionality into potential acidic groups leads to a substantial increase in the acidity 5. 6 For example, the monotriflylamide 1 has a p K a value of 11.06, which implies nine orders of magnitude higher acidity than benzoic acid itself (p K a =20.7). An additional N ‐triflate moiety lowers the p K a value to 6.17 (Scheme ).…”

Desulfatiglans anilini Initiates Degradation of Aniline With the Production of Phenylphosphoamidate and 4-Aminobenzoate as Intermediates Through Synthases and Carboxylases From Different Gene Clusters

“…Triethylammonium N -phenylphosphoramidate ( Chanley and Feageson, 1958 ; Burlingham and Widlanski, 2001 ) (3): Dibenzyl N -phenylphosphoramidate (synthesis reaction 2) (510 mg, 1.44 mmol) and Pd catalyst (190 mg, 10% Pd/C) were suspended in ethanol (10 mL) containing triethylamine (0.5 g). The flask was evacuated and backfilled with hydrogen 4 times.…”

“…Dibenzyl N-phenylphosphoramidate (synthesis reaction 2) was isolated as off-white solid in 78% yield (13.51 g). 1 H-NMR (400 MHz, CDCl 3 ): δ 5.06, 5.16 (AB part of ABX, 2 J HH = 11.7 Hz, 3 J HP = 7.5 Hz, 4H, OCH 2 -Ph), 6.93-6.99 (m, 1H para , N-C 6 H 5 ), 7.00-7.05 (m, 2H ortho , N-C 6 H 5 ), 7.17-7.25 (m, 2H meta , N-C 6 H 5 ), 7.30 (s, 10H, OCH 2 C 6 H 5 ); 13 C-NMR (101 MHz Triethylammonium N-phenylphosphoramidate (Chanley and Feageson, 1958;Burlingham and Widlanski, 2001) 3: Dibenzyl N-phenylphosphoramidate (synthesis reaction 2) (510 mg, 1.44 mmol) and Pd catalyst (190 mg, 10% Pd/C) were suspended in ethanol (10 mL) containing triethylamine (0.5 g). The flask was evacuated and backfilled with hydrogen 4 times.…”