Dimethyl N-Aryl phosphoramidates : structural effects on bonding and solvolytic reactivity

The acid catalysed hydrolysis of a number of ring alkyl substituted dimethyl N-aryl phosphoramidates, (MeO)2P(0)NHAr, has been studied by measuring the rates of hyd~olysis with the aid of a UV spectrophotometer. These rates have been correlated with the pKa values of the corresponding ani I inium iOhs and the slope of this reactivitybasicity relationship for phosphoramidate with ortho substituents (6 = 0~85) is found to differ from that for substrates with meta and para substituents (S = 0,36). Determination of the thermodynamic parameters indicates that the entropy of activation is approximately constant for the substrates studied and the strongly negative values ~ -I -I (~S = 155,4 - 17,5 J mole K ) are consistent with an A2 type mechanism.

Grantor dc:publisher.institution

Department of Chemistry

Year dc:date.issued

1981

Author dc:creator

• Rijkmans, Bloys Peter

Advisor dc:contributor.advisor

• Modro, Tom A

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/11427/13518

OAI identifier oai:identifier

oai:open.uct.ac.za:11427/13518