Ecdysone-22-phosphate

The formation of phosphate esters of ecdysteroids constitutes a potentially valuable mechanism for storing high titers of insect steroids in a form that is inactive but that provides a readily available source of the active ecdysteroid. Embryos of . gregaria contain a phosphatase that can hydrolyze ecdysone 22-phosphate (36) and this enzyme could effect the controlled release of ecdysone and possibly other ecdysteroids at appropriate stages of insect development. 

Isaac, R. E., M. E. Rose, H. H. Rees, and T. W. Goodwin Identification of Ecdysone-22-phosphate and 2-Deoxyecdysone-22-phosphate in Eggs of the Desert Locust, Schistocerca Gregaria, by Fast Atom Bombardment Mass Spectrometry and N.M.R. Spectroscopy. J. Chem. Soc. (London), Chem. Commun. 1982, 249. 

Generally useful reagent with a high silyl donor ability will not react with amino groups will not cause formation of enol-ether on unprotected ketone groups especially useful for ecdysones, norepinephrine, dopamine, steroids, sugars, sugar phosphates, and ketose isomers... 

Tsoupras et al. used 31p nmr to detect the presence of phosphate groups in the 22-adenosinemonophosphoric ester of 2-deoxy-ecdysone and 22-phospho-2-deoxyecdysone (34). Quantitative NMR has been used in several studies. Wayne et al. used 51p nmr for quantitative analysis of organophosphorous pesticides (35). Zon et al. used NW to study chemical and microsomal oxidation of cyclophosphamide ( ), and to determine the half-life of a cyclophosphamide analogue (37). 

Table IV lists structures of some uncommon conjugates to which NMR has been applied in characterizations. Both the xenobiotics and the conjugates are of diverse structural types. Ecdysone-type compounds, although not xenobiotics in the strict definition of the term, are included because they represent conjugation with a phosphate group.

Adenosine-0 OH (34) 0-P=0 Insect eggs. 400 MHz 31p 61.0 CO3OO C-22 678.5 (apoc=4 Hz) - shifted downfield 4.6 ppm from ecdysone l C aided ribose identification. iH aided adenine identification. Phosphate conj. at C-22 also reported. 

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