Selective reactions phosphorylation

A remarkably selective phosphorylation at HO-3 in L-ascorbic acid and its 5,6-O-isopropylidene derivative has been achieved with phosphoryl chloride in aqueous pyridine204 the use of acetone-pyridine as the solvent led to a much less selective reaction. 

In a series of elegant studies, Miller and colleagues demonstrated that small peptides containing modified histidine residues (re-methyl-histidine) were effective catalysts for enantioselective acylation and phosphorylation reactions [12, 13]. As peptides in this family are able to transfer stereochemical information, these catalysts were also tested to carry out site- and regio-selective reactions, which take place against kinetic expectations. The screening of a small library (36 members)... 

We have said little about selective reactions of pentoses so we shall turn now to the synthesis of nucleotides such as AMP. In nature, ribose is phosphorylated on the primary alcohol to give ribose-5-phosphate. This is, of course, an enzyme-catalysed reaction but it shows straightforward chemo-selectivity such as we should expect from a chemical reaction. 

It has been reported that Cplex-isoelectronic theory predicts endo selectivity in Diels-Alder reactions. Phosphorylated nitroso alkenes react with cycUc dienes to give hetero Diels-Alder-type cycloadducts and subsequent aza-Cope rearrangement gives 5,6-dihydro-4H-l,2-oxazines (Scheme 20). ... 

Fig. 2. Synthesis of uma2enil (18). The isonitrosoacetanihde is synthesized from 4-f1iioroani1ine. Cyclization using sulfuric acid is followed by oxidization using peracetic acid to the isatoic anhydride. Reaction of sarcosine in DMF and acetic acid leads to the benzodiazepine-2,5-dione. Deprotonation, phosphorylation, and subsequent reaction with diethyl malonate leads to the diester. After selective hydrolysis and decarboxylation the resulting monoester is nitrosated and catalyticaHy hydrogenated to the aminoester. Introduction of the final carbon atom is accompHshed by reaction of triethyl orthoformate to...

The method has then been efficiently used to remove selectively the exocycHc methylsulfanyl group from phosphorylated thiopyranyl derivatives 85 resulting from hetero Diels-Alder reaction of a phosphono-dithioformate or dithioacetate (see Sects. 2.1.2 and 2.2.3). FimctionaHzed thiopyrans 86 [17,18,27a] are thus obtained (Scheme 25). Owing to this selective desulfanylation, phospho-nodithioesters can be used as heterodienophiles in place of the corresponding phosphonothioaldehyde, not described so far and probably very unstable. 

Like Na,K-ATPase, gastric H,K-ATPase also exhibits a p-nitrophenylphosphatase (/>NPPase) activity. This phosphatase activity is dependent on Mg and K, or one of its congeners with the same order of selectivity as for the ATPase activity, yielding a specific activity of 6D84% of the maximal ATPase activity [4,136,137]. Phosphorylation by pNPP has not been demonstrated and transport is also not catalyzed by this substrate. As in the ATPase reaction the effect of on the... 

The formation of 151 from the phosphonate 171 could be proved only by indirect means. Electron-rich aromatic compounds such as N,N-diethylaniline and N,N,N, N -tetraethyl-m-phenylenediamine U0 1I9> and N-methylaniline 120> are phosphorylated in the para- and in the ortho- plus para-positions by 151. Furthermore, 151 also adds to the nitrogen lone pair of aniline to form the corresponding phosphor-amidate. Considerable competition between nucleophiles of various strengths for the monomeric methyl metaphosphate 151 — e.g. aromatic substitution of N,N-diethylaniline and reaction with methanol or aromatic substitution and reaction with the nitrogen lone pair in N-methylaniline — again underline its extraordinary non-selectivity. 

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