Nitrogen Nitrophenyl phosphate

Herschlag and Jencks (1987) extended the study of the reactions of pyridines with phosphates (Skoog and Jencks, 1983 discussed on p. 109) to incorporate the role of metal ions. /i-Nitrophenyl phosphate dianion undergoes reaction with substituted pyridines by a mechanism that has considerable dissociative character since is very small (0.2). That is, the value of Pnu indicates that the rate-determining step involves little decrease in electron density at the nitrogen atom of the attacking pyridine. 

In an investigation of the hydrolysis mechanism of the phe-pro peptide bond specific to HIV-1 protease by ab initio molecular-orbital calculations using a model compound, the rate-determining step has been found to be the protonation of the substrate proline nitrogen and its activation energy has been estimated to be 23.95 kcal mor A dizinc aminopeptidase has been shown to hydrolyse the phosphodiesterase substrate bis-/ -nitrophenyl phosphate (200) with impressive efficiency (fecat/ unoat =... 

Under nitrogen atmosphere, 1.0 mL 2.0 M butyllithium in hexane (2.0 mmol) and 398 mg 4-nitrobenzenesulfenyl chloride (2.1 mmol) were added sequentially to a solution of 328 mg 2-(4-methoxyphenyl)-prop-2-en-l-ol (2.0 mmol) in anhydrous THF at 0°C. After being stirred for 30 min, the reaction mixture was diluted with EtOAc, washed with aqueous phosphate buffer (400 mM, pH 6.8) and brine, dried over MgS04, and concentrated in vacuo. The residue was purified by flash chromatography on silica gel with hexane/EtOAc (2 1) as an eluent to afford 2-(4-methoxyphenyl)prop-2-en-l-yl-4-nitrophenyl sulfoxide as a yellow solid, in a yield of 55%, m.p. 99.9-100.7°C, Rf = 0.25 (hexane/EtOAc = 2 1). 

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