Simple hydrolysis

The a-acetobutyrolactone, with or without isolation, can be used in the preparation of various 5-substituted 2-butanone derivatives, presumably by decarboxylation of the acetoacetic acid obtained by ring hydrolysis. Simple hydrolysis gives 5-hydroxybutan-2-one (158) and acidolysis with hydrochloric acid gives 5-chlorobutan-2-one in good yields (159). 

Poly(lactide-coglycolide). Mixtures of lactide and glycolide monomers have been copolymerised in an effort to extend the range of polymer properties and rates of in vivo absorption. Poly(lactide- (9-glycolide) polymers undergo a simple hydrolysis degradation mechanism, which is sensitive to both pH and the presence of ensymes (32). 

Saponification can proceed direcdy as a one-step reaction as shown above, or it can be achieved indirectly by a two-step reaction where the intermediate step generates fatty acids through simple hydrolysis of the fats and oils and the finishing step forms soap through the neutralization of the fatty acid with caustic soda. There are practical considerations which must be addressed when performing this reaction on a commercial scale. 

The synthetic routes to TgRg compounds are outlined in Figure 5. Simple hydrolysis of RSiCl3 or RSi(OMe)3 precursors does not give good yields of Tg derivatives as they tend to be formed as by-products in the presence of higher... 

An elegant alternative to the simple hydrolysis method is to use precursors already containing several of the required siloxane linkages. Thus, T8ReR 2... 

Reagents are also available to convert thiocarbonyl compounds back to carbonyls. Simple hydrolysis is the most common method for converting thiocarbonyls to carbonyls. Stirring thioketones with 4-nitrobenzaldehyde and a catalytic amount of TMSOTf gives the ketone. ... 

Aldicarb undergoes simple hydrolysis at pH values above 7, whereas at pH values <5 an elimination reaction intervenes (Figure 1.20) (Bank and Tyrrell 1984). 

Unusual monosodium salts of ethyl- or phenylsilanetriol RSi-(OH)2ONa. 1.37H20 (R = Et or Ph) are reported to be obtained by treating the polymers obtained from the simple hydrolysis of RSiCl3 with 20% aqueous NaOH/EtOH (103). Relatively few silanols have been isolated from the cleavage of siloxanes, as the conditions required to carry out such reactions are likely to cause further reactions of any silanols formed. 

Much work has been done since, and it is quite evident that this seemingly simple hydrolysis to acetic and salicylic acids is both complex and controversial. I am fortunate that I can refer the reader to the excellent and detailed review by Clark A. Kelly151 already mentioned in Section 5.61. The most complete and thorough kinetic studies of the factors involved in the hydrolysis of aspirin are undoubtedly those by Edwards17 3, which were further elaborated by Garrett.174... 

The conversion of 7 to 8 is a simple hydrolysis of an acetal. Acetals are functionally equivalent to alcohols + carbonyls and can be interconverted with them under acidic conditions. Several reasonable mechanisms can be drawn for this transformation, but all must proceed via S l substitutions. 

With methods for the quantitative analysis of amino acids to hand, the way was now open for the determination of amino acid sequences. Purified bovine insulin was relatively freely available. On the basis of ultracentrifugal analysis (Gutfreund and Ogston), a molecular weight of 12,000 was assumed—as it later emerged, a factor of 2 too high. One of the advantages from the choice of insulin as the protein to sequence was that tryptophan is absent. A 100% recovery of the amino acids could therefore be obtained easily by simple hydrolysis with HC1. In 1948 Tristram reported the complete amino acid composition of the protein. 

Microorganisms can inactive toxicants by cleavage of a bond by the addition of water. Such reactions may involve a simple hydrolysis of an ester bond, as with the insecticide Malathion by a carboxyesterase enzyme ... 

Since it was shown that free radical ring-opening polymerization (2) made it possible to introduce functional groups, such as esters C3j, carbonates (4), thioesters (5), and amides (6), into the backbone of an addition polymer, it was reasoned that simple hydrolysis would produce the desired oligomers that could be terminated with various combinations of hydroxyl, amino, thiol, and carboxylic acid groups. 

Boronic acid hnkers (Tab. 3.6) are useful for the attachment of diols, the protection of glycosides [105] or as precursors for the metal-mediated cleavage [106]. The boronates formed are sensitive to water and simple hydrolysis is sufficient for cleavage. Recently, Carreaux and Carboni developed a new boronate-based strategy for traceless sohd-phase synthesis of aromatic compounds [107]. 

Chemical/Physical. Emits toxic phosgene fumes when heated to decomposition (Sax and Lewis, 1987). In a 0.50 N sodium hydroxide solution at 20 °C, chlorpropham hydrolyzed to aniline derivatives. The half-life of this reaction was 3.5 d (El-Dib and Aly, 1976). Simple hydrolysis leads to the formation of 3-chlorophenylcarbamic acid and 2-propanol. The acid is very unstable and is spontaneously converted to 3-chloroaniline and carbon dioxide (Still and Herrett, 1976). 

Other pathways in the reaction between nitrate esters and alkalis are simple hydrolysis and P-eHmination — the abstraction of a P-hydrogen atom simple hydrolysis (Eq. (5)) ... 

We have found that the primary amine moiety can be protected from organolithium reagents and polymers by use of the N,N-bis(trimethylsilyl)amine, -N(TMS)p, protecting group. In turn, the N(TMS)2 substituted4 polymers can be converted to primary amine polymers by simple hydrolysis (Eqs. 12-14 (14.52). 

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