Phosphorylation method

By combining the above phosphorylation methods, ttie preparation of the 1-a,4 -diphosphate became possible. Of the two phosphate residues, the more stable one on the 4 -position was introduced first. Thus, was converted, via the corresponding oxazoline, into the fully protected diphosphate which on hydrogenolysis afforded... 

Figure II. A new phosphorylation method with butyllithium and a phosphoro-...

This phosphorylation method is thus a very convenient and versatile one, especially adequate for our synthetic study of lipid A as utilized below. It could be confirmed from the above experiments that no cleavage and transposition of acyl groups occurred by the use of butyllithium under the reaction conditions employed. 

The new phosphorylation method was further applied to halides having N-benzyloxycarbonyl (Z) ( and >), N-acetyl ( ) and N-... 

The presence in bacterial lipopolysaccharides of phosphoryl-ated ethanolamine residues (1) prompted us to experiment with the incorporation of this group. When compound was treated with an activated phosphorylethanolamine derivative, prepared by the procedure shown in Figure 8, the a-phosphate [a]j) +66.7° (chloroform), was obtained in 46% yield. The reaction is similar to that with dibenzyl tributylstannyl phosphate. Thus, the new phosphorylation method may have wide application in the synthesis of C-l phosphorylated lipid A analogs. 

Glycosyl phosphates are important building blocks in carbohydrate synthesis. Hindsgaul and co-workers18 applied a capture-phosphorylation method with a polystyrene-supported phosphoramidite to simplify their synthesis (entry 14). Unreacted alcohols are removed by washing the resin and the desired glcyophosphates are released in high purity by a standard... 

Anomeric phosphorylation by glycosylation methods In the above-discussed phosphorylation methods, the sugar hydroxyl acts as the nucleophile and the phosphorylating agent as the electrophile. However, phosphorylation of the anomeric centre may also be performed by another approach where the saccharide contains a leaving group. 

Problems with phosphorylation In the preparation of myoinositol phosphates and related compounds, the most crucial problem to be solved is the multiple phosphorylation of polyol derivatives. Especially vicinal diols 4 are very difficult to be transformed to the diphosphates 7, mainly because the monophosphorylation product 5 is prone to cyclization to the 5-membered cyclic phosphate 6 rather than undergoing the second phosphorylation (Scheme 1-5). These facts stimulated efforts to develop a new phosphorylation methodology, and in 1987 two types of new phosphorylation methods employing P(III) and P(IV) reagents were successfully introduced for the synthesis of Ins(l,4,5)P3 and Ins(1,3,4,5)P4. 

Graves, D.J. Use of peptide substrates to study the specificity of phosphorylase kinase phosphorylation. Methods Enzymol., 99, 268-278 (1983)... 

A large number of reported peptidomimetic compounds possess very low aqueous solubility at physiological pH owing to the high lipophilicity inherent in these structures. Phosphorylation can yield improved biological activities for such compounds. This is at least the case for the phosphorylated neurokinin-1 receptor antagonist and the HIV protease inhibitor of Fig. 36.7 described by scientists from Merck and Upjohn, respectively. Clean phosphorylation methods are now available some of them are shown in Fig. 36.8. 

There are two strategies used currently for the preparation of phosphopeptides the building block approach, in which pre-formed protected phospho-amino acids are incorporated during the course of chain assembly, and the global phosphorylation method, which involves post-synthetic phosphorylation of serine, threonine, or tyrosine side-chain hydroxyl groups on the solid support. 

Monomers derived from trimellitic anhydride, mainly V-carboxyphenyltrimel-litimides and V-(co-carboxyalkylene)trimellitimides have been also used many times as starting materials for the synthesis of poly (amide imide)s. These poly (amide imide)s have been traditionally prepared by low temperature solution polycondensation, from diamines and imide-diacid chlorides [182], but they have been also successfully synthesized by the phosphorylation method of direct polyamidation [184], from diamines and imide-diacids [185-188] as depicted in Scheme (36). Trimellitic acid imide (4-carboxyphthal-imide) has also been used for the preparation of poly(amide imide)s, by reaction with aliphatic and aromatic diamines in solution at moderate temperatures [189]. 

Apart form AABB poly(ether imide)s AB polymers have also been described. It has been claimed that the self-condensation of 4-(4-aminophenoxy) phthalic anhydride hydrochloride leads to high molecular weight poly(ether imide)s [201]. Similar compositions have been more recently reported, taking as starting materials 3- and 4-(4-aminophenoxy) phthalic acid hydrochloride, and using the phosphorylation method to attain AB poly(ether imide)s of only moderate molecular weight (/ inh 0.15-0.25 dL/g) [202]. 

In an efficient new one-pot phosphorylation method, O-diethylboiyl derivatives of carbohydrates were treated sequentially with phosphine enolate (41), prepared in situ from acetyl acetone and diphenylchlorophosphine (40), and hydrogen peroxide, to give sugar diphenylphosphinates (42), as illustrated in Scheme 8. Use of diethylchlorophosphite in place of chlorophosphine (40) furnished sugar diethylphosphates. ... 

Phosphorylation methods that are used in the synthesis of GPIs are adopted from the weU-estabhshed protocols for the synthesis of oligonucleotides. The two commonly used methods are both based on phosphitylation that is followed by oxidation. Phosphitylation of an alcohol with H-phosphonates activated via transient formation of mixed anhydride with pivaloyl chloride followed by oxidation with iodine in wet pyridine is commonly used to prepare the phosphate salts (Scheme 12.3, introduction of the phosphoHpid phosphodiester). The reagents... 

Watanabe Y, Mukaiyama T (1978) An efficient phosphorylation method by the activation of alcohol. Chem Lett 349-352... 

The previously reported phase transfer phosphorylation method (see Sect. 11.8) failed when applied to hydrazine. A solid-liquid phase transfer technique was successful, permitting the monophosphorylation of hydrazine with a variety of dialkyl phosphites. Phosphorylation of the second nitrogen could not be effected under phase transfer conditions and was achieved otherwise. 

Polyamides with short trimethylene aliphatic flexible sequences were described by Nasr-Isfahani et al. [4]. The poly condensation of the diacid l,3-(4-carboxy phenoxy)propane with various aromatic diamines by direct polycondensation provide PAs with moderate yield. These PAs were found to be soluble in polar aprotic solvents and soluble even in acetone and in THF. Ferreiro et al. [5] described the effect of lateral oxyethylene moieties on the properties of aromatic polyisophthalamides. Several polyisophthalamides containing short sequences of oxyethylene as pendent substituents were synthesized by the reaction of three aromatic diamine monomers and four novel diacid monomers containing pendent oxyethylene units by the phosphorylation method of polycondensation. The polymers were prepared in high yield and high molecular weight. 

A novel phosphorylation method for wyo-inositol derivatives involving application of the Atherton-Todd reaction under solid-liquid phase transfer conditions has been developed. ... 

Chattopadhyaya, J. B. and Reese, C. B. (1979) Some observations relating to phosphorylation methods in oligonucleotide synthesis. Tetrahedron Lett, 20, 5059-5062. 

There are numerous reviews on phosphorylation methods in biological molecules, some of which include aryl phosphoramidochloridates. ... 

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