Ester Hydrolysis to Produce an Alcohol

Sigma-Aldrich performed an ester hydrolysis to produce an alcohol that decomposes quickly. None of these compounds could be disclosed [2]. Scale-up could not satisfy the commercial interest in the labile product, as the yield decreased strongly with batch vessel size. Seventy percent yield was obtained at 51 scale, 35% at 201 scale, and 10% at 1001 scale. 

The investigation in a microreactor was initially hampered by the presence of an insoluble compound for the ester process [2]. Since this reactant had to be changed, a process development study had to be carried out. A model reaction, an ester hydrolysis yielding a stable alcohol, was used instead of the real one, in order to facile the process development. Twelve different conditions were used. Having acquired the process know-how, the same kind of process development was done for the real reaction in only 2 h with success. 

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Ester hydrolysis is the reaction of an ester with water to break an ester linkage and produce an alcohol and a carboxylic acid. This process is simply the reverse of the esterification reaction (Reaction 5.8). Strong acids are frequently used as catalysts to hydrolyze esters ... 

Like ester hydrolysis, saponification resnlts in a breaking of the ester linkage and produces an alcohol and a carboxylic acid (see Section 8.4 for more on saponification). However, unlike ester hydrolysis, saponification is done in solutions containing strong bases such as potassium or sodium hydroxide. The carboxylic acid is converted to a salt under... 

A stimulating development of urea alcoholysis has been demonstrated very recently for better AE, in an innovative integrated process that incorporates fatty ester hydrolysis to co-amino-alkanoic acids [44], Within the scope of this chapter, the most interesting step of this process is the recycling of waste alcohol, formed by the hydrolysis step, for urea alcoholysis. Dialkyl carbonate is produced together with ammonia thereafter, the ammonia is engaged in the amination reaction to obtain the amino acids. The overall process avoids the storage of NH3 that is necessary for the amination route, and transforms a waste product-the alcohol-into the valuable dialkyl carbonate. 

In their quest for enantiomerically pure compounds, organic chemists have developed several new techniques for the preparation of enantiomerically pure materials. One approach is to use enzymes. Enzymes are themselves chiral, so they can produce single enantiomer products. A class of enzymes used for this purpose is the esterases, which catalyze the hydrolysis of esters to give an alcohol and a carboxylic acid. 

The synthetic conqround methoprene possesses all of these desirable features. Its synthesis utilizes several reactions we have studied, including ox3mercuration-demCTcuration to give the tertiary methyl ether, ester hydrolysis (Section 8-5), and PCC oxidation of a primary alcohol to produce an aldehyde (Section 8-6). 

Sulfation is defined as any process of introducing an SO group into an organic compound to produce the characteristic C—OSO configuration. Typically, sulfation of alcohols utilizes chlorosulfuric acid or sulfur trioxide reagents. Unlike the sulfonates, which show remarkable stability even after prolonged heat, sulfated products are unstable toward acid hydrolysis. Hence, alcohol sulfuric esters are immediately neutralized after sulfation in order to preserve a high sulfation yield. 

A novel route to azelaic acid is based on butadiene. Butadiene is dimerized to 1,5-cyclooctadiene, which is carbonylated to the monoester in the presence of an alcohol. Hydrolysis of this ester foUowed by a caustic cleavage step produces azelaic acid in both high yield and purity (56). 

Nicolaou in his model system for an approach to the thiopeptide antibiotic thiostrepton, in particular, the elaboration of the quinaldic acid moiety. The tetrahydroquinoline 21 was converted to the A-oxide by /n-CPBA oxidation. Subsequent treatment with TFAA, to carry out the Boekelheide reaction, was followed by hydrolysis of the resultant ester to produce 22 as a mixture of alcohols. 

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. 

Some male arctiid moths produce their courtship pheromone from dietary pyrrolizidine alkaloids acquired during feeding by the larvae [ 126]. Conversion of monocrotaline to hydroxydanaidal by males is accomplished by aromatiza-tion, ester hydrolysis and oxidation of an alcohol to the aldehyde [7]. In the case of Utetheisa ornatirx the stereo-configuration at C7 of the dietary alkaloid is the same as the pheromone released (R). In contrast, another arctiid, Creatono-tos transiens, can convert a dietary precursor alkaloid with the (S) configuration at C7 (heliotrine) to (l )-hydroxydanaidal. The biosynthesis occurs by first oxidation-reduction at C7 to convert the stereochemistry and then proceeds through aromatization, hydrolysis, and oxidation [7]. 

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