Esterification dehydrating agents

Esterification is readily achieved in THF in the presence of a dehydrating agent. The boronate is stable to chromatography, has good stability to 2 M TEA/ CH2CI2, but is not stable to aqueous 1 M NaOH. Cleavage is also achieved by hydrogenolysis. ... 

The fact that the amount of total linalol decreases whilst the richness in linalyl acetate increases, proves that linalol appears in the plant at an earlier period than its acetic ester. Further, the free acetic acid acting on the linalol esterifies a portion of it, whilst another portion of this terpene alcohol is dehydrated, with the production of limonene and. dipentene, which are the usual resultants of linalol in presence of certain dehydrating agents. This view is corroborated by the fact that the quantity of the mixed terpenes increases during the esterification, without the slightest variation being observed in the ratio between the... 

Reaction (fill. Esterification with Continuous removal of Water. (P. R. S., 25, 831 J. C. S., 87, 1657.)—In this method, which requires little elaboration, it is necessary that the acid and ester have high boiling points compared with that of water. The last is continually volatilised with the alcohol and circulated over a dehydrating agent which absorbs it—the alcohol being returned to the reaction vessel. 

Esterification is effected in the cold in presence of alkali or by heating the alcohol and anhydride together, usually in presence of a dehydrating agent—e.g., fused zinc chloride, anhydrous sodium acetate, etc. Preparation 204.—Mannitol Hexacetate. 

For labile multifunctional substrates, the first step in the OBO synthesis, esterification with 3-methyl-3-oxetanemethanol, can be accomplished using the carboxylic acid and a dehydrating agent such as dicyclohexylcarbodiimide (DCC) [Scheme 2.111]. ... 

The acid in reaction 3 functions as an esterification catalyst. The toluene in this reaction serves as a dehydrating agent (toluene forms an azeotrope with ethanol and water containing 12% water [18]). In addition, the toluene renders the reaction solution a poor solvent for the byproduct salts and thus facilitates their separation. 

A titanium triflate, TiCl(OTf)3, proved to be an excellent catalyst for equimolar esterification of a carboxylic acid and an alcohol in the presence of (Me2SiO)4 as a dehydrating agent (Eq. 215) [510]. The catalyst is required only in very small amounts (0.1 mol %) and a variety of combinations of carboxylic acids and alcohols enter this esterification. 

They are commonly prepared by the esterification of ethyl alcohol by the corresponding acids monochloracetic, bromoacetic, etc., using sulphuric acid as dehydrating agent. This acid first reacts with alcohol to form ethyl hydrogen sulphate ... 

Dehydration. The salt (1) is an excellent dehydrating agent that effects esterification, amidation, and anhydride formation. 

Dehydrating Agent. TMSCl is also a suitable dehydrating agent for scavenging water generated in various reactions. For example, in the esterification of 5-methylpyrazinoic acid with n-nonanol, a 44% yield of the desired ester can be distilled out directly from the reaction mixture of the acid, alcohol, and TMSCl (eq 47). ... 

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