Acid hydrolysis derivatives

Acrylics. Acetone is converted via the intermediate acetone cyanohydrin to the monomer methyl methacrylate (MMA) [80-62-6]. The MMA is polymerized to poly(methyl methacrylate) (PMMA) to make the familiar clear acryUc sheet. PMMA is also used in mol ding and extmsion powders. Hydrolysis of acetone cyanohydrin gives methacrylic acid (MAA), a monomer which goes direcdy into acryUc latexes, carboxylated styrene—butadiene polymers, or ethylene—MAA ionomers. As part of the methacrylic stmcture, acetone is found in the following major end use products acryUc sheet mol ding resins, impact modifiers and processing aids, acryUc film, ABS and polyester resin modifiers, surface coatings, acryUc lacquers, emulsion polymers, petroleum chemicals, and various copolymers (see METHACRYLIC ACID AND DERIVATIVES METHACRYLIC POLYMERS). 

Manufacture of Fatty Acids and Derivatives. Splitting of fats to produce fatty acids and glycerol (a valuable coproduct) has been practiced since before the 1890s. In early processes, concentrated alkaU reacted with fats to produce soaps followed by acidulation to produce the fatty acids. Acid-catalyzed hydrolysis, mostly with sulfuric and sulfonic acids, was also practiced. Pressurized equipment was introduced to accelerate the rate of the process, and finally continuous processes were developed to maximize completeness of the reaction (105). Lipolytic enzymes maybe utilized to spHt... 

Preparation of Arylcarboxylic Acids and Derivatives. The general Friedel-Crafts acylation principle can be successfully appHed to the preparation of aromatic carboxyUc acids. Carbonyl haUdes (phosgene, carbonyl chloride fluoride, or carbonyl fluoride) [353-50-4] are diacyl haUdes of carbonic acid. Phosgene [75-44-5] or oxalyl chloride [79-37-8] react with aromatic hydrocarbons to give aroyl chlorides that yield acids on hydrolysis (133) ... 

Acidic hydrolysis of these hydroxyaLkyl hydroperoxides yields carboxyUc acids, whereas basic hydrolysis regenerates the parent aldehyde, hydrogen peroxide, and often other products. When derived from either aldehydes or cycHc ketones, peroxides (1, X = OH, = H, R, = alkylene or... 

Enzymatic Method. L-Amino acids can be produced by the enzymatic hydrolysis of chemically synthesized DL-amino acids or derivatives such as esters, hydantoins, carbamates, amides, and acylates (24). The enzyme which hydrolyzes the L-isomer specifically has been found in microbial sources. The resulting L-amino acid is isolated through routine chemical or physical processes. The D-isomer which remains unchanged is racemized chemically or enzymatically and the process is recycled. Conversely, enzymes which act specifically on D-isomers have been found. Thus various D-amino acids have been... 

The ansatrienins ate produced by Streptomjces collinus Tb 1982. The stmctures (Fig. 12) were assigned on the basis of spectral data of the intact antibiotics as well as several derivatives. Acid hydrolysis of the ansatrienins yields L-alanine. The stmctures of ansatrienins A and B ate the same as those for mycotrienins 1 and 11, respectively, except for the configuration of the alanine moiety. The ansatrienins ate active against fungi (45,46). 

In the acid hydrolysis process (79—81), wood is treated with concentrated or dilute acid solution to produce a lignin-rich residue and a Hquor containing sugars, organic acids, furfural, and other chemicals. The process is adaptable to all species and all forms of wood waste. The Hquor can be concentrated to a molasses for animal feed (82), used as a substrate for fermentation to ethanol or yeast (82), or dehydrated to furfural and levulinic acid (83—86). Attempts have been made to obtain marketable products from the lignin residue (87) rather than using it as a fuel, but currently only carbohydrate-derived products appear practical. 

A number of disinfectants apparentiy owe their activity to formaldehyde, although there is argument on whether some of them function by other mechanisms. In this category, the dmg with the longest history is hexamethylenetetramine (hexamine, urotropin) [100-97-0] which is a condensation product of formaldehyde and ammonia that breaks down by acid hydrolysis to produce formaldehyde. Hexamine was first used for urinary tract antisepsis. Other antimicrobials that are adducts of formaldehyde and amines have been made others are based on methylolate derivations of nitroalkanes. The apphcations of these compounds are widespread, including inactivation of bacterial endotoxin preservation of cosmetics, metal working fluids, and latex paint and use in spin finishes, textile impregnation, and secondary oil recovery (117). 

This can be achieved by an indirect method. The lithio derivative is first reacted with a borate ester. Sequential acid hydrolysis and oxidation yields the corresponding hydroxy derivative. This procedure is illustrated by the conversion of 2-lithiobenzo[6]thiophene to 2-hydroxybenzo[6]thiophene, which exists predominantly in the 2(3//)-one tautomeric form (200) <70JCS(C)1926). 

Derivatives like (491 R = Me) can be de-5-methylated by Raney nickel in ethanol or concentrated hydrochloric acid. Acid hydrolysis of (491 R = acyl) also affords 5-mercap-topyrazoles, whereas alkaline hydrolysis of the pyrazolium salt (495) furnishes methanethiol and antipyrine. 

The dibenzosuberyl ether is prepared from an alcohol and the suberyl chloride in the presence of triethylamine (CH2CI2, 20°, 3 h, 75% yield). It is cleaved by acidic hydrolysis (1 N HCl/dioxane, 20°, 6 h, 80% yield). This group has also been used to protect amines, thiols, and carboxylic acids. The alcohol derivative can be cleaved in the presence of a dibenzosuberylamine. ... 

This group was developed for protection of the 5 -OH group in nucleosides. The derivative is prepared from the corresponding triaiylmethyl chloride, and is cleaved by reductive cleavage (Zn/AcOH) of the phenacyl ether to the p-hydroxyphenyl-diphenylmethyl ether followed by acidic hydrolysis with formic acid. ... 

A variety of cyclic ortho esters,including cyclic orthoformates, have been developed to protect czs-1,2-diols. Cyclic ortho esters are more readily cleaved by acidic hydrolysis (e.g., by a phosphate buffer, pH 4.5-7.5, or by 0.005-0.05 M HCl) than are acetonides. Careful hydrolysis or reduction can be used to prepare selectively monoprotected diol derivatives. 

With this ortho ester good selectivity for the axial alcohol is achieved in the acidic hydrolysis of a pyranoside derivative." ... 

A carbonyl group can be protected as a sulfur derivative—for example, a dithio acetal or ketal, 1,3-dithiane, or 1,3-dithiolane—by reaction of the carbonyl compound in the presence of an acid catalyst with a thiol or dithiol. The derivatives are in general cleaved by reaction with Hg(II) salts or oxidation acidic hydrolysis is unsatisfactory. The acyclic derivatives are formed and hydrolyzed much more readily than their cyclic counterparts. Representative examples of formation and cleavage are shown below. 

These derivatives are prepared to protect a-hydroxy carboxylic acids they are cleaved by acidic hydrolysis of the acetal structure (HCl, DMF, 50°, 7 h, 71% yield), or basic hydrolysis of the lactone. ... 

This derivative is readily cleaved by acidic hydrolysis (dil. CF3COOH, CH2CI2, 10 min, quant.). It is cleaved 3000 times faster than the r-BOC derivative because of stabilization of the cation by the biphenyl group. BnSH... 

Benzyl carbamates substituted with one or more halogens are much more stable to acidic hydrolysis than are the unsubstituted benzyl carbamates.For example, the 2,4-dichlorobenzyl carbamate is 80 times more stable to acid than is the simple benzyl derivative. Halobenzyl carbamates can also be cleaved by hydrogenolysis with Pd-C. The following halobeni yl carbamates have been found to be useful when increased acid stability is required. 

The MMTr derivative is easily prepared from amino acids, and is readily cleaved by acid hydrolysis (5% CCI3CO2H, 4°, 5 min, 100% yield). ... 

The THP derivative of the imidazole nitrogen in purines has been prepared by treatment with dihydropyran (TsOH, 55°, 1.5 h, 50-85% yield). It is cleaved by acid hydrolysis. ... 

Bromocresol green (3.8...5.4) aliphatic carboxylic acids[103,187 — 204] triiodobenzoic acid [205], derivatives of barbituric acid [206] amphetamine derivatives [207, 208] phenazones, morazone [209] alkaloids [91, 209] nephopam [210] phenyramidol metabolites [211] diethylalkylacetamide derivatives [212] zipeprol (Mirsol) [213] thalidomide and hydrolysis products [214] cyclohexylamine derivatives [215] herbicide residues [216]... 

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