Diethyl-phosphate ester

Reductive removal of oxygen from aromatic rings can also be achieved by reductive cleavage of aryl diethyl phosphate esters. 

Diethyl phosphate esters of the sterically congested phenols of calixarenes have been prepared in acceptable yields (>55%) and used in the preparation of meta-cyclophanes [8]. The corresponding reaction using diethyl phosphite, with triethylamine in place of the quaternary ammonium catalyst, results in only partial phosphorylation of the hydroxyl groups. 

Sodium-Ammonia, For the reduction of a phenol to an aromatic hydrocarbon a solution of the phenol and diethyl hydrogen phosphite in carbon tetrachloride is treated with triethylamine and allowed to stand for 24 hrs. for complete separation of triethylamine hydrochloride (1). The phenol diethyl phosphate ester is collected. 

The rearrangement of dialkyl 3-pyridinyl phosphates and thiophosphates under the influence of a base (Ida) at low temperatures has been shown to be remarkably regioselective. In the case of the diethyl phosphate ester, the sole product is diethyl (2-hydroxy-4-pyridinyl)phosphonate with the corresponding thiophosphate O, O, (9-triester, diethyl (3-hydroxy-2-pyridinyl)phosphonothioate is formed in a large excess over the (2-hydroxy-4-pyridinyl)phosphonothioic diester ... 

Musliner-Gates dehydroxylation of (+ )-bulbocapnine (31) generated ( + )-laureline (32). Also, reduction of the diethyl phosphate ester of ( + )-bulbo-capnine with lithium in liquid ammonia afforded the phenol (33). ... 

An efficient method for the deoxygenation of a phenol, predating the Musliner-Gates procedure, consists of the reaction of the phenol with diethyl phosphorochloridate. The resulting aryl diethyl phosphate ester is then hydro-genolyzed with sodium in liquid ammonia. ... 

Replacement of the Phenolic OH Groins. Recendy the synthesis of completely dehydroxylated calix[4]arene 14d by reductive cleavage (K in liquid ammonia) of the tetrakis(diethyl phosphate) ester of p-tert-butylcalix[4]arene 9b has been reported [13]. Starting from the 1,3-di- and tetraesters of 9b we could isolate the partially dehydroxylated calix[4]arenes 14a-c [14]. 

For the preparation of multiply phosphorus bridged systems, we studied the pyrolytic behavior of calixarene dialkyl phosphate ester derivatives. These compounds are useful intermediates for the OH-depletion of the calixarenes [15, 16] and for the preparation of aminocalixarenes [17]. These esters can be prepared by treatment of the calixarenes with a dialkyl chlorophosphate in the presence of base [18]. In the case of 1, under mild conditions, the distal (i.e, 1,3-) bis(diethyl phosphate ester) derivative is obtained (2a) while under more drastic conditions (CH2Cl2/aq NaOH, phase transfer catalysis) the tetraphosphate 2b is formed [15a]. Calixarene mono diisopropyl phosphate ester and l,2-bis(diisopropyl phosphate ester) derivatives (2c and 2d) were prepared by mono- or dideprotonation by LDA of the monospirodienone derivative 3 followed by treatment with the corresponding dialkyl chlorophosphate [15e, 17b]. Aromatization of the spirodienone products was achieved by heating or by their treatment with HBr yielding the dialkylphos-phate esters derivatives 2c and 2d [15e, 17b]. 

Reminiscent of the iodolactionization process, Bartlett and Jemstedt developed an indirect but efficient way for the diastereoselective epoxidation of homoallylic alcohols. They found that the treatment of the diethyl-phosphate ester of a homoallylic alcohol such as 10 with iodine produced cyclic phosphate 11 in high yield and good syw-diastereose-lectivity. After hydrolytic treatment with sodium ethoxide, the epoxide 12 was formed with no change of diasteromeric ratio (Scheme 37.3). 

SCHEME 37.3. Diastereoselective epoxidation of the diethyl-phosphate ester of a homoallylic alcohol. 

Mixtures of a titanium complex of saturated diols, such as TYZOR OGT, and a titanium acylate, such as bis- -butyl-bis-caproic acid titanate, do not have a yellowing or discoloring effect on white inks used to print polyolefin surfaces (506). The complexes formed by the reaction of one or two moles of diethyl citrate with TYZOR TPT have an insignificant color on their own and do not generate color with phenol-based antioxidants (507). The complexes formed by the addition of a mixture of mono- and dialkyl phosphate esters to TYZOR TBT are also low color-generating, adhesion-promoting additives for use in printing polyolefin films (508). 

Phosphate groups can also be removed by dissolving-metal reduction. Reductive removal of vinyl phosphate groups is one method for conversion of a carbonyl compound to an alkene.224 (See Section 5.7.2 for other methods.) The required vinyl phosphate esters are obtained by phosphorylation of the enolate with diethyl phospho-rochloridate or /V A /V -tetramethyldiamidophosphorochloridate.225... 

N. Nikolaides, 1. Schipor, and B. Ganem 246 CONVERSION OF AMINES TO PHOSPHO ESTERS DECYL DIETHYL PHOSPHATE... 

Decyl diethyl phosphate Phosphoric acid, decyl diethyl ester (9) (20195-16-8)... 

In the initial screening of various Cinchona alkaloids, the addition of diethyl phosphate 41 to IV-Boc imine 40 in toluene revealed the key role of the free hydroxyl group of the catalyst. Replacing the C(9)-OH group with esters or amides only results in poor selectivity. Quinine (Q) was identified as an ideal catalyst. A mechanistic proposal for the role of quinine is presented. Hydrogen-bonding by the free C(9)-hydroxyl group and quinuclidine base activation of the phosphonate into a nucleophilic phosphite species are key to the reactivity of this transformation (Scheme 9). 

TRYPTAMINE, N,N-DIETHYL-4-HYDROXY 4-INDOLOL, 3-[2-(DIETHYLAMINO)ETHYL] N,N-DlETHYL-4-HYDROXYTRYPTAMINE 3-[2-(DIETHYLAMINO)ETHYL]-4-INDOLOL CZ-74 4-HO-DET PHOSPHATE ESTER TRYPTAMINE, N,N-DIETHYL-4-PHOSPHORYLOXY 4-INDOLOL, 3-[2-(DIETHYLAMINO)ETHYL], PHOSPHATE ESTER N,N-DIETHYL-4-PHOSPHORYLOXYTRYPTAMINE 3-[2-(DIETHYLAMINO)ETHYL]-4-INDOLOL,... 

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