2,4-Dinitrophenyl group migration

A detailed study of the specific rates of solvolysis of N,N,N, N -tetra-methyldiamidophosphorochloridate (80) (TMDAPC) with analysis in terms of the extended Grunwald-Winstein equation has been reported (Scheme 19). The stereochemistry of nucleophilic attack at tetracoordinate phosphorus was also discussed." The initial reaction of bis (2,4-dinitrophenyl) phosphate (BDNPP) (81) with hydroxylamine involves release of 1 mol 2,4-dinitrophen-oxide ion and formation of a phosphorylated hydroxylamine (82), which reacts readily with further NH2OH, giving the monoester (83). The intermediate (82) also breaks down by two other independent reactions one involves intramolecular displacement of aryloxide ion (83) and the other involves migration of the 2,4-dinitrophenyl group from O to N and formation of phosphorylated 2,4-dinitrophenylhydroxylamine (84) (Scheme 20)." ... 

Three papers in the same line of work have been published from Kopple s school. Kopple and Nitecki (161) found that in the hydrolyses of PNPA and 2,4-dinitrophenyl acetate by Cyclo-(Gly-His-Gly-Tyr-Gly-Gly), the acylation by the sub-arate occurs fira at the histidyl imidazole group, and then the acyl group migrates intramoleculaily to the phenolic oxygen of the tryosyl teadue. This reaction route is different from that of a-chymotrypsin, but it is quite interesting to show that the functional groups of the cyclic hexapeptide interact mwe or less. 

It is also possible for two alkyl groups to migrate from boron to an intermediate such as 207.151 When borane 211 was treated with A-chloro-0-(dinitrophenyl)hydroxylamine (212), a double migration of the alkyl groups led to amino alcohol 213 upon oxidation. 152... 

Dinitrophenylation of the imidazole NH practically eliminates its basic character, yet the 2,4-dinitrophenyl (DNP) group also shares a less desirable property with real acyl groups it can migrate to free amines ... 

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