Phosphate caged compounds

Little is known about the reactions of radical cations of organophosphorus compounds (P such as aryl phosphates and phosphonates as caged compounds and reagents in organic syntheses [85-91]. To elucidate PET reactions including P as the key intermediate, PR and -y-R are used here. 

Thermal condensation reactions which produce polyphosphates are of great industrial importance. These involve the heating of solid acid phosphate salts whereby P-O-P linkages are formed with the elimination of water (3.101). Numerous long-chain, ring and cage compounds can be produced by reactions of this kind (Chapter 5.4). 

There are two distinct types of experiments with caged compounds to be considered here those concerned with the development and assessment of new compounds and those connected with specific applications to different physiological processes. We shall discuss the two problems in succession. Detailed descriptions of methods for assessing the rates and quantities of the photolytic formation of active substrates from different caged compounds are presented by Walker et al. (1988) and Milbum et al. (1989). Some aspects of the decomposition of npe-ATP will serve as an example for such investigations. The broad absorption band of l-(2-nitrophenyl)ethyl phosphate in the near UV, allows the use of a wavelength for photolysis which results in minimum interference with that used for monitoring the reaction. The rapid ( > 10 s ) initial formation of the presumed acinitro intermediates (with extinction coefficients of 6.3 x 10 cm and 9.1 X 10 M cm at 380 nm and 406 nm respectively) and the concomi-... 

Molecular phosphonate cages with metal, P, and O atoms as model compounds and a source for phosphate materials 99ACR117. 

Scheme 3.3 Overall photodeprotection reaction of two p-hydroxyphenacyl caged phosphate compounds. See text for more details. (Reprinted in part with permission from reference [49]. Copyright (2006) American Chemical Society.)...

The l,2-diacyl-l-/-butylhydrazines have been found to be effective as insect-growth regulators. Caged bicyclic phosphates have also shown promise as insecticides. Wang and Huang have combined these effects in the synthesis of compounds 266 and 267 <2000PS(161)173>. Compounds 268 and 269 have been synthesized for their potential... 

Waiawalkar. M, G. Roesky, H. W., Murugavel. R. Molecular phosphonate cages Model compounds and starting materials for phosphate materials, Acc. Chem. Res. 1999. 32, n 7-126,... 

Detailed vibrational spectroscopy on crystalline ammonium hexafluoro-phosphate confirms phase transitions at ca. 190 and 130 K, and possible structures are discussed. The presence of appreciable amounts of HF in the hexahydrate of HPF, is shown by recent n.m.r. measurements, and the compound should be formulated as HsO+ PF, HF,4H20. Each of the species, H2O, H3O+, and HF, participates fully in a four-co-ordinate scheme of hydrogen-bonding to give the truncated octahedral cage shown in Figure 8. 

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