Preparation and properties of esters

Introduction. The reaction between an acid and an alcohol yields an ester and water  

The distillate contains ethyl acetate, and small amounts of alcohol, acetic acid, ether, water, and sulfur dioxide. Transfer the distillate into a separatory funnel, and add small amounts of a saturated solution of sodium carbonate until the upper layer is no longer acid (test with litmus). Remove the lower aqueous layer. The remaining layer contains the ester and a small amount of ethanol. Shake with 10 ml of concentrated calcium chloride solution to remove traces of alcohol. Dry the ester with 6 g of anhydrous magnesium sulfate, then transfer to a distilling flask and fractionate. The portion which boils below 73° is rejected. The fraction boiling at 73-80° is collected. The yield is about 40-50 g. 

The usual method of acetylation by means of acetic anhydride or a mixture of acetic acid and anhydride is to reflux the hydroxy compound and the anhydride for 10-15 minutes. In the present instance, the temperature is kept low by the presence of ice and the hydrolysis of the anhydride is inhibited, permitting it to react with the hydroxy compound. Phenol and other aromatic hydroxy compounds can be acetylated by this method. 

Esters, under appropriate conditions, undergo hydrolysis. This reaction is the reverse of esterification as shown in the equation on page 207. Esters react with aqueous or alcoholic ammonia to form amides. A number of reactions of esters are due to activity of the carbonyl group and the adjacent a-hydrogen atoms. The reaction of esters with Grignard reagents to form ketones or tertiary alcohols, and the various condensations, are examples of this type of reaction. 

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Recently, Bayliss et al. [132] described the synthesis of anthracene-9-carbonyl chloride and its aplications as a label for fluorescence and UV absorbance detection of hydroxy compounds. The preparation and properties of esters of short-chain alcohols, diols, trichothecene mycotoxins and sterols were investigated. Anthracene-9-carbonyl chloride was prepared from commercial anthracene-9-carboxylic acid. Derivatization was carried out in acetonitrile free from water or active hydrogen compounds. The reaction rate was dejjendent on the structure of the alcohol. The derivatization of diethylene glycol was complete at ambient temp>erature within 10 min (0.25 M reagent) or 30 min (0.1 M reagent) without a catalyst, but required 1 h for diolesteroL testosterone and the trichothecene T-2 toxin. For sterically hindered alcohols such as t-butanol and 17a-methyl-testosterone, more than 10 h, or refluxing for 1 h, was needed to complete the reaction. The derivatives had absorption maxima at 250 run. Both normal and reversed phase HPLC were applied to the separation of the derivatives. 

We 11 begin by describing the preparation and properties of p keto esters proceed to a discussion of their synthetic applications continue to an examination of related species and conclude by exploring some recent developments m the active field of synthetic car banion chemistry... 

Jensen, The Preparation of 2,2,2-Trinitroethyl- 4,4-dinitropentanoate , NAVORD 2498 (1952) 4) M. Hill, Preparation and Properties of 2,2-Dinitropropanol Esters , NAVORD 2497 (1952)... 

Preparation and Properties of Free-Amine Pivalate Ester (FAPE) 45... 

K Barlos, D Papaioannou, D Theodoropoulus. Preparation and properties of A -trityl amino acid 1-hydroxybenzotriazole esters. Int J Pept Prot Res 23, 300, 1984. 

Refs 1) Beil 2, 742, [6391 Sc Jl904l 2) Beil, not found (Dinitro) 3) M.E, Hill, "Preparation and Properties of 2,2-Dinitro-propanol Esters , NAVORD 2497(1952)... 

Babayan, V. K., and McIntyre, R. T. 1971. Preparation and properties of some polyglycerol esters of short and medium chain length fatty acids. /. Am. Oil Chem. Soc., 48, 307-309. 

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