Di alkyl Esters

Methyl, propyl, butyl, etc., malonic esters are also obtained in a similar manner. It is to be observed that aryl halides do not undergo this reaction. The di-alkyl esters are obtained from the mono-alkyl esters in the same way as the latter are obtained from malonic ester. But although di-alkyl compounds are not formed directly in any quantity, yet it frequently happens that a little is obtained in the preparation of the mono-alkyl compound from 1 mol. of sodium ethoxide and 1 mol. of alkyl halide, owing to the mono-derivative reacting with more sodium and alkyl halide. This may be prevented when necessary by using only half the calculated quantity of sodium and alkyl halide. By this means the yield of benzoyl malonic ester for example is raised from 55% to 85% in its preparation from sodium, benzoyl chloride and malonic ester. (B., 44, 1507.)... 

The di-alkyl esters are made from the mono-alkyl esters in a manner exactly similar to that by which the mono-alkyl esters are made from acetoacetic ester itself. 

Dithiophosphorsaure-O - (l-alkoximino-alkylester)-0,S-di alkyl ester werden durch Umsetzung der Chlorid-0,S-diester mit Hydroxamsauren erhalten z.B.264 ... 

Di-basic and Di-alcoholic.—That tartaric acid is di-basic, i.e. that it contains two carboxyl groups is shown by the fact that it forms di-alkyl esters and di-metal salts. 

Di-potassium salt Tartaric acid Di-alkyl ester... 

That it contains two alcohol hydroxyl groups is proven by the fact that its di-alkyl esters form di-acetyl derivatives ... 

Long-chain di-alkyl esters have medium compatibility with most polymers and can act both internally and externally, hence they are often used to obtain a balanced lubrication. 

Titanium Phosphorous Containing Chelates. The reaction of a mixture of mono (alkyl) diacid orthophosphate, di(alkyl)monoacid orthophosphate, and TiCl in a high boiling hydrocarbon solvent such as heptane, with nitrogen-assisted evolution of Hberated HCl, gives a mixture of titanium tetra(mixed alkylphosphate)esters, (H0)(R0)0=P0) Ti(0P=0(0R)2)4 in heptane solution (100). A similar mixture can be prepared by the addition of two moles of P2O5 to mole of TiCl in the presence of six moles of alcohol ... 

Acidic alkyl esters of phosphoric acid, of which dibutyl-phosphoric acid (HDBP) and di(2-ethylhexyl) phosphoric acid (HDEHP) are typical,... 

A number of A-acyloxy-A-alkoxybenzamides 100 have been shown to decompose in mesitylene at temperatures above 100°C giving a complex mixture of products including the A-alkyl adduct 106, the corresponding alkyl ester 108, anhydride 101 and a product (up to 60% yield in cases), which was characterised as 1,4,2-di-oxazoline 104 (Scheme 21). Minor products included hydroxamic ester 105 and mesitylene adduct 109. 

The alkylation reaction is initiated by the activation of the alkene. With liquid acids, the alkene forms the corresponding ester. This reaction follows Markovnikov s rule, so that the acid is added to the most highly substituted carbon atom. With H2S04, mono- and di-alkyl sulfates are produced, and with HF alkyl fluorides are produced. Triflic acid (CF3S020H) behaves in the same way and forms alkyl triflates (24). These esters are stable at low temperatures and low acid/hydrocarbon ratios. With a large excess of acid, the esters may also be stabilized in the form of free carbenium ions and anions (Reaction (1)). 

Bromine-atom atomic resonance absorption spectrometry (ARAS) has been applied to measure the thermal decomposition rate constants of CF3Br in Kr over the temperature range 1222-1624 K. The results were found to be consistent with recently published theory. The formation of cyclopent[a]indene and acenaphthylene from alkyl esters of biphenyl-mono- and -di-carboxylic acids has been observed in flash vacuum pyrolyses at 1000-1100 °C. The kinetics and mechanisms of free-radical generation in the ternary system containing styrene epoxide, / -TsOH, and i-PrOH have been examined in both the presence and absence of O2. ... 

European Union Risk Assessment Report (2003) 1,2-Benzenedicarboxylic acid, di-C8-10-branched alkyl esters, C9-rich and di- isononyl phthalate (DINP), European commission Joint Research Centre, EUR 20784 EN, Office for Official Publications of the European Communities... 

Simple alkyl esters show rather low stereoselectivity. However, highly hindered esters derived from 2,6-dimethylphenol or 2,6-di-/-butyl-4-methylphenol provide the anti stereoisomers. 

Problem 13.16 Alkyl esters of di- and triphosphoric acid are important in biochemistry because they are stable m the aqueous medium of living cells and are hydrolyzed by enzymes to supply the energy needed for muscle ontraction and other processes, (a) Give structural formulas for these esters, (b) Write equations for the lydrolysis reactions that are energy-liberating. ... 

Di(alkyl or aryl)amino-l,2,4-thiadiazoles (90 R,R = alkyl or aryl) are similarly obtainable in 60-85% yields from the appropriate disubstituted amidinothioureas (89 R,R = alkyl or aryl).56,57 The preparation of the latter from monosubstituted guanidines (87) and isothiocyanate esters (88) might conceivably yield the isomeric ami-... 

Reaction XLIV. (b) Condensation of Alkyl and Aryl Halogen Compounds with the Sodio- and other Metallo-derivatives of Ethyl Aceto-acetate and its Homolognes. (A., 186, 214 201, 143 213, 143.)—Like malonic ester, acetoacetic ester contains two 1 3-carbonyl groups with a methylene group in position 2. It is only to be expected then that it yields with metallic sodium or sodium alcoholate sodio-derivatives from which mono- and di-, alkyl and aryl homologues can be obtained by treatment with a suitable halide, including halogen esters. Acetoacetic acid... 

In the preparation of some of the higher mono-alkyl acetoacetic esters the yield is sensibly lowered, owing to the formation of di-alkyl compounds due to secondary reactions of the same type as those described on p. 137. This in like manner can be remedied by using only half the calculated quantity of sodium and alkyl halide. The unattacked acetoacetic ester is recovered by distillation. 

Reaction LXVII. (b) Acid Hydrolysis of Alkyl Derivatives of Ethyl Acetoacetate. (B., 19, 227.)—When acetoacetic ester or its mono- or di-alkyl derivatives are refluxed with concentrated aqueous or alcoholic potash, acid hydrolysis occurs and 2 mols. of acetic acid, or 1 mol. of that acid, and 1 mol. of a mono- or di-substituted derivative are obtained. 

This method is suitable for the preparation of mono- and di-a-substituted /3-ketoesters. Bromoacetates fail in this reaction. Yields with ethyl a-bromopropionate are considerably lower (30-36% with capronitrile) however, ethyl esters are useful for higher-molecular-weight compounds whose sec-alkyl esters are cracked by distillation. With 3-pentyl a-bromopropionate, the yields are slightly higher (53-60% with capronitrile). Both aromatic and aliphatic nitriles are suitable benzonitrile gives yields comparable to those obtained with capronitrile. Alkyl substitution in the a- and /8-positions (cf. Note 4) of aliphatic nitriles lowers the yield to 29% and 38%), respectively 7-substitution has no effect. 

A seleno-Claisen rearrangement has been used179 to synthesise mono-, di-, and tri-allylated selenothioic and S-alkyl esters with high regio- and stereo-selectivity. 

In 2-trimethylsilylethyl 4-phenylbenzoate 44, the C—Si and C—O ester bonds are in an antiperiplanar conformation, and the C—O ester bond is significantly longer than expected for an alkyl ester bond at a primary centre. This is consistent with a oq si T c o interaction in the ground state. In /raw.v-2-(di methyl phenyl si ly I )cyclohexyl-3,5-dinitrobcnzoate 45, the dihedral angle between the C—Si and C—O ester bonds is found to be just over 60°, and there appears to be little lengthening of the C—O bond. 

An alternative method for preparation of 4-oxophospholanes 126 is oxidation of 3-hydroxyphospholane 127. Alkylation of 126 at the methylene of the 5-position, where acidic property is expected by the two electron-withdrawing groups of adjacent P=0 and C=0 groups to the methylene corresponding to two ester groups of maleate, gives mono- and di-alkylation products 128 and 129, respectively (Scheme 43). 

They are a versatile surfactant type, with some properties analogous to those of ether sulphates. Unlike sulphate (which is a sulphuric acid mono alkyl ester), phosphate can form di- and triester, giving a wider range of structures and, with them, the ability to tailor the product to a greater number of application areas. 

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