The mechanism of dephosphorylation of bis(2,4-dinitrophenyl) phosphate in mixed micelles of cationic surfactants and lauryl hydroxamic acid.
Mixed micelles of cetyltrimethylammonium bromide (CTABr) or dodecyltrimethylammonium bromide (DTABr) and the alpha-nucleophile, lauryl hydroxamic acid (LHA) accelerate dephosphorylation of bis(2,4-dinitrophenyl)phosphate (BDNPP) over the pH range 4-10. With a 0.1 mole fraction of LHA in DTABr or CTABr, dephosphorylation of BDNPP is approximately 10(4)-fold faster than its spontaneous hydrolysis, and monoanionic LHA(-) is the reactive species. The results are consistent with a mechanism involving concurrent nucleophilic attack by hydroxamate ion (i) on the aromatic carbon, giving an intermediate that decomposes to undecylamine and 2,4-dinitrophenol, and (ii) at phosphorus, giving an unstable intermediate that undergoes a Lossen rearrangement yielding a series of derivatives including N,N-dialkylurea, undecylamine, undecyl isocyanate, and carbamyl hydroxamate.
Departamento de Química, Universidade Federal de Santa Catarina, 88040-900 Florianópolis, SC, Brazil.
Marcelo
M
Silva
Renata S
RS
Mello
M Akhyar
MA
Farrukh
Janio
J
Venturini
Clifford A
CA
Bunton
Humberto M S
HM
Milagre
Marcos N
MN
Eberlin
Haidi D
HD
Fiedler
Faruk
F
Nome
D002412:Cations; D006877:Hydroxamic Acids / Q000737:chemistry*; D007700:Kinetics; D009682:Magnetic Resonance Spectroscopy; D008823:Micelles; D010755:Organophosphates / Q000737:chemistry*; D010766:Phosphorylation; D011199:Potentiometry; D021241:Spectrometry, Mass, Electrospray Ionization; D013501:Surface-Active Agents / Q000737:chemistry*
D002412:Cations; D006877:Hydroxamic Acids; D008823:Micelles; D010755:Organophosphates; D013501:Surface-Active Agents; C546103:bis(2,4-dinitrophenyl) phosphate; C546102:lauryl hydroxamic acid