Alcohol groups neutral

E Tertiary alcohol group, neutral, prone to elimination by dehydration at high temperatures. Where the hydroxyl group at E is converted to an ester such as valerate, e.g. betamethasone valerate, thermal elimination of the ester can occur quite readily. Another decomposition reaction of the valerate esters is the... 

I) Refluxing said benzyl ester with an aqueous alcoholic alkali metal hydroxide solution to saponify the benzyl ester group, neutralizing the saponification mixture by the addition of hydrochloric acid, extracting the neutralized mixture with chloroform, and separating the resulting (S,N-ditrityl-L-cysteinyl)-L-proline. 

Dissolve a sample containing 0.5 meq anion-active material with a ether carboxylic acid group in alcohol and neutralize with 0.5 N NaOH on phenol-phthalein. Transfer this solution to a 250-ml graduated flask with a stopper and make up to the mark with distilled water. Introduce into a 100-ml graduated cylinder with a stopper ... 

Hydrolysis appears to be the most important abiotic degradative mechanism for organophosphate esters under basic pH conditions. Under neutral and acidic conditions, the reaction slows considerably and could become an insignificant removal mechanism. The hydrolysis proceeds by a stepwise mechanism in which one alcohol group is removed at a time. The first step is cleavage of a P-OR bond (where "R" is an aryl or alkyl group) to produce a diester of phosphoric acid, which, under basic conditions, becomes an anion. 

In some acylations it may even be necessary to employ three equivalents of the ester enolate. The example of Figure 10.54 is such a case. The acylating ester contains an alcohol group and, of course, the H atom of the hydroxyl group is acidic. Thus, it destroys the first equivalent of the ester enolate through transfer of the proton to form the neutral ester. The second equivalent of the ester enolate is consumed in building up the /3-ketoester intermediate, whereas the third equivalent of the ester enolate deprotonates this intermediate quantitatively. 

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