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Reactions of bis(2,4-dinitrophenyl) phosphate with hydroxylamine.
Domingos, Josiel B; Longhinotti, Elisane; Bunton, Clifford A; Nome, Faruk.
Affiliation
  • Domingos JB; Departamento de Química, Universidade Federal de Santa Catarina, Florianópolis, SC 88040-900, Brazil.
J Org Chem ; 68(18): 7051-8, 2003 Sep 05.
Article in En | MEDLINE | ID: mdl-12946148
For dephosphorylation of bis(2,4-dinitrophenyl) phosphate (BDNPP) by hydroxylamine in water, pH region 4-12, the observed first-order rate constant, k(obs), initially increases as a function of pH, but is pH-independent between pH 7.2 and pH 10. The initial BDNPP cleavage by nonionic NH(2)OH (<0.2 M) involves attack by the OH group and follows first-order kinetics, but the overall initial reaction of BDNPP liberates ca. 1.7 mol of 2,4-dinitrophenoxide ion (DNP). This initial reaction generates a short-lived O-phosphorylated hydroxylamine, 2, followed by three possible reactions: (1) reaction of 2 with hydroxylamine, generating 2,4-dinitrophenyl phosphate (DNPP, 3), which subsequently forms DNP; (2) intramolecular displacement of the second DNP group and rapid decomposition of the cyclic intermediate to form phosphonohydroxylamine and eventually inorganic phosphate; (3) a novel rearrangement with intramolecular aromatic nucleophilic substitution involving a cyclic intermediate and migration of the 2,4-dinitrophenyl group from O to N. Values of k(obs) increase modestly with pH > 10, the reaction is biphasic, and the yield of DNP increases. An increase in [NH(2)OH] also increases the yield of DNP, due largely to accelerated hydrolysis of DNPP.
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Collection: 01-internacional Database: MEDLINE Language: En Journal: J Org Chem Year: 2003 Document type: Article Affiliation country: Brazil Country of publication: United States
Search on Google
Collection: 01-internacional Database: MEDLINE Language: En Journal: J Org Chem Year: 2003 Document type: Article Affiliation country: Brazil Country of publication: United States