Hydroxyalkyl phosphates

Nonionic polyethylene glycol 2-hydroxyalkyl and 3-alkoxy-2-hydroxyalkyl phosphate surfactants were prepared by the reaction of a polyethylene glycol... 

Amylopectin is the polymeric component of starch and consists mainly of glucose units joined at the 1,4-positions. Relative molar mass tends to be very high, e.g. between 7 and 70 million. A variety of modified starches are used commercially which are produced by derivatisation to give materials such as ethanoates (acetates), phosphates, and hydroxyalkyl ethers. Modified and unmodified starches are used in approximately equal tonnages, mainly in papermaking, paper coatings, paper adhesives, textile sizes, and food thickeners. 

Diester methods have been used to synthesize analogues of the initiator codon ApUpG in which the adenine residue has a fixed torsion angle, as for instance in (78),132 and triester methods have been used to prepare dinucleoside phosphates and codon analogues133 134 containing the hydroxyalkyl nucleosides 9-(4 -hydroxybutyl)-adenine (80), 9-(3 -hydroxypropyl)adenine (81), and 1 -(3 -hydroxypropyl)uracil (82), with a view to determining the effect of the achiral residues on the c.d. spectra. 

Adsorption inhibitors act by forming a film on the metal surface. The action of traditional oil-based red lead paint formulations presumably involves the formation of soaps and the precipitation of complex ferric salts that reinforce the oxide film. There has been substantial interest in recent years in development of replacements for lead-based and chromate-based inhibitor systems. Adsorption inhibitors based on pol3rmers have been of particular interest. In this volume, Johnson et al. and Eng and Ishida discuss inhibitors for copper 2-undecylimidazole is shown to be effective in acid media, where it suppresses the oxygen reduction reaction almost completely. Polyvlnyllmidazoles are shown to be effective oxidation inhibitors for copper at elevated temperatures. Also in this volume, Chen discusses the use of N-(hydroxyalkyl)acrylamide copolymers in conjunction with phosphate-orthophosphate inhibitor systems for cooling systems. 

The percent inhibition was calculated according to the equation in Table II. As shown in Table II, the results indicated that when compared to the polyacrylic acid, copolymers of acrylic acid and N-(hydroxyalkyl)-acrylamide were quite effective in inhibiting calcium phosphate formation at the normal use dosage of 10 to 20 ppm. Among the three copolymers tested, acrylic acid/... 

N-(co-Hydroxyalkyl)pyrrolidines react at the mobile hydrogen atom of the hydroxy group with the formation of thiophosphonates 139 [130] and phosphates 140 [131, 132] and 141 [133] ... 

The formation of phosphate esters from amine-catalyzed reactions between dialkyl phosphites and ketones often accompanies the expected production of (a-hydroxyalkyl)phosphonic acid esters (see Section 2.1). It is also known that under... 

The base-catalysed rearrangement of the alkyl phosphates, particularly those possessing secondary alkyl groups, (50), into (l-hydroxyalkyl)phosphonic esters... 

Hydroxyalkyl and Epoxyalkyl Acids. - The reaction most widely adopted for the preparation of (l-hydroxyalkyl)phosphonic esters is that attributed to Abramov and involves the interaction of hydrogenphosphonates with aldehydes or ketones, sometimes in the presence of a base catalyst. The same reaction has now been shown to be catalysed by mineral phosphates e.g. fluoroapatite. The same process, catalysed by the complex (134) [(R)-form] gives the same esters in 50-95% yields and with 55-9d% e.e.s The study of the diastereoselective phosphonoylation of aldehydes using chiral 1,3,2-diazaphospholidine reagents has continued with an examination of the use of the stereoisomers of (135), which... 

The mode of addition of hydrogenphosphonates to fluorinated ketones can also be complex. The addition of dialkyl, diphenyl or bis(trimethylsilyl) hydrogenphosphonates to methyl trifluoromethyl ketones occurs in the expected manner, but this contrasts with the behaviour of aryl perfluoralkyl ketones in the presence of triethylamine at room temperature, when the products, obtained even under such mild conditions, are phosphate esters (reaction 6), a situation which represents lack of stability of the hydroxyphospho-nate rather than novelty of the reaction under identical conditions, the corresponding alkyl aryl ketones fail to react. The same reaction with mixed-halogen ketones is still more involved, and the nature of the products depends on the reaction conditions if these are of a mild nature, and with catalysis by triethylamine or pyridine (depending on the particular ketone), the product is the expected (hydroxyalkyl)phosphonate 177, whereas with... 

Although it has been stated that di- and tri-haloketones and a-haloaldehydes (irrespective of the degree of halogen substitution) tend to yield only enol phosphate esters, further qualification of this statement is appropriate. The formation of silyl ethers from aldehydes or ketones and silyl phosphites has already been noted (see section III.A). Reactions between silyl phosphites and trifluoroacetaldehyde or perfluoroacetone and other similar compounds initially lead to silyl ethers of (a-hydroxyalkyl)phosphonic diesters in which all the fluorine is retained, although subsequent change leads to fluorinated enol phosphate esters. Sekine et also observed the formation of (a-silyloxyalkyl)phospho-... 

Two further complicating features may be noted. The first is of little, if any, practical consequence with regard to the formation of oxoalkyl phosphonates, but is to be found in the formation of enol phosphates from a-polyhaloketones, when the latter may be accompanied by simple dehalogenation of the carbonyl reactant when treated with phospho-rus(III) esters particularly when reactions are carried out in protic solvents This is coupled with the second feature, which consists in the formation of (1-hydroxyalkyl)phos-phonic acid esters from a trialkyl phosphite and the substituted a-monohaloacetophenone also in the presence of a protic solvenr . ... 

Instability in the supposedly stable phosphorus-carbon bond displays itself not only in unfortunate ways, leading as it does to side reactions and the formation, in synthesis, of unwanted by-products, but also in a constructive manner, forming the basis of reaction sequences of outstanding value in synthesis, as for example in alkene-forming reactions. Instability is an inherent property of (a-hydroxyalkyl)phosphonic acids which manifests itself in phosphorus-carbon bond cleavage as a result of the action of heat or of alkali, and which can lead either to dissociation into precursors or to rearrangement to phosphates (a-oxoalkyl)phosphonic derivatives are susceptible to attack by nucleophiles, a process which also results in carbon-phosphorus bond fission. 

The rearrangement of (a-hydroxyalkyl)phosphonate into phosphate ester is not universal (l-hydroxy-2-nitroalkyl)phosphonic esters do not rearrange under the influence of heat whether aided, or not, by added base and the reaction between (Me0)2P(0)H and MeCOCH=CHPh at 130-160 °C yields the 1,2-adduct (105 R = Me) which is stable to base (MeO or EtjN). On the other hand, 105 (R = H) partially decomposes in the presence of MeO and the products include the phosphate 106 together with methyl cinnamate and cinnamyl alcohol, as might be expected from the action of base on cinnamaldehyde Other compounds which undergo base-catalysed rearrangements include 107, the indanones 108 (R = H or the hydroxy phosphinic esters 109 (X = O or S, R =... 

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