Esters, preparation from acids

Plasticizers. About 2.5% of U.S. adipic acid consumed in 1988 was used in two basic types of adipic ester based plasticizers (195). Simple adipate esters prepared from Cg—alcohols are used especially as PVC plasticizers (qv). Eor special appHcations requiring low volatility or extraction resistance, polyester derivatives of diols or polyols are preferred. 

Production of cellulose esters from aromatic acids has not been commercialized because of unfavorable economics. These esters are usually prepared from highly reactive regenerated cellulose, and their physical properties do not differ markedly from cellulose esters prepared from the more readily available aHphatic acids. Benzoate esters have been prepared from regenerated cellulose with benzoyl chloride in pyridine—nitrobenzene (27) or benzene (28). These benzoate esters are soluble in common organic solvents such as acetone or chloroform. Benzoate esters, as well as the nitrochloro-, and methoxy-substituted benzoates, have been prepared from cellulose with the appropriate aromatic acid and chloroacetic anhydride as the impelling agent and magnesium perchlorate as the catalyst (29). 

Aiyl esters, prepared from the phenol and an acid chloride or anhydride in the presence of base, are readily cleaved by saponification. In general they are more readily cleaved than the related esters of alcohols, thus allowing selective removal of phenolic esters. 9-Fluorenecarboxylates and 9-xanthenecarboxylates are also cleaved by photolysis. To permit selective removal, a number of carbonate esters have been investigated aryl benzyl carbonates can be cleaved by hydrogenolysis aryl 2,2,2-trichloroethyl carbonates, by Zn/THF-H20. 

Dimethoxybenzyl esters prepared from the acid chloride and the benzyl alcohol are readily cleaved oxidatively by DDQ (CH2CI2, H2O, rt, 18 h, 90-95% yield). A 4-methoxybenzyl ester was found not to be cleaved by DDQ. The authors have also explored the oxidative cleavage (ceric ammonium nitrate, CH3CN, H2O, 0°, 4 h, 65-97% yield) of a variety of 4-hydroxy- and 4-amino-substituted phenolic esters. ... 

Ortho esters are among the few derivatives that can be prepared from acids and esters that protect the carbonyl against nucleophilic attack by hydroxide or other... 

Ortho esters are one of the few derivatives that can be prepared from acids and esters that protect the carbonyl against nucleophilic attack by hydroxide or other strong nucleophiles such as Grignard reagents. In general, ortho esters are difficult to prepare directly from acids and are therefore more often prepared from the nitrile. Simple ortho esters derived from normal alcohols are the least stable in terms of acid stability and stability toward Grignard reagents, but as the ortho ester becomes more constrained, its stability increases. 

Geranyl chloride can be prepared from geraniol by the careful use of triphenylphosphine in carbon tetrachloride. Tris(dimethylamino)phosphine reacts with carbon tetrachloride to form the complex (42) which can be used to form the enol esters (43) from acid anhydrides. Similarly, aldehydes form the alkenes (44), and esters or amides of trichloroacetic acid are converted to glycidic esters. ... 

The most common plasticisers for PVC are phthalate esters prepared from aliphatic C8 alcohols. For high temperature applications higher molecular weight esters are used, e.g., from mellitic acid, which are resistant to volatilisation and are used for PVC interiors in cars (to prevent fogging of windscreens). 

The diastereofacial selective imine-ene reactions with a-imino esters prepared from (—)-8-phenylmenthyl glyoxylate have provided an efficient entry to the asymmetric synthesis of a-amino acids, and a Lewis acid-mediated intramolecular imine-ene reaction has been used for the key spirocyclization step in a recent synthesis of (—)-perhydrohistrionicotoxin. Asymmetric azo-ene reactions have been effected using the chiral azo-enophile, di-(—)-(lR,2S)-2-phenyl-l-cyclohexyldiazenedicarboxylate. ... 

These syntlieses give no indication as to the structure of aspartic acid, the constitutional formula of which is based upon Kolbe s work, that it is amino-succinic acid the only synthesis of aspartic acid which confirms this constitution appears to be that by Piutti in 1887. Sodium oxalacetic ester, prepared from oxalic ester and acetic ester in the presence of sodium ethylate —... 

The most important of the carbohydrate esters of nitric acid are the polysaccharide nitrates, particularly cellulose nitrate or nitrocellulose (NC) and starch nitrate ( nitrostarch ) which is much less used. Nitric esters prepared from other sugars such as saccharose and lactose are not of any importance as explosives. 

Cleavage conditions for alkyl benzyl ethers prepared from acid-labile benzyl alcohols are similar to those for the corresponding benzyl esters (Table 3.30). Aryl benzyl ethers, however, are generally cleaved more easily by acidolysis than esters or alkyl ethers. Phenols etherified with hydroxymethyl polystyrene, for instance, can even be released by treatment with TFA (Entry 1, Table 3.31). It has also been shown that Wang resin derived phenyl ethers are less stable than Wang resin derived esters towards refluxing acetic acid [29]. Alternatively, boron tribromide may be used to cleave aryl ethers from hydroxymethyl polystyrene [573],... 

Garces, R. and Mancha, M. 1993. One-step lipid extraction and fatty acid methyl esters preparation from fresh plant tissues. Anal. Chem. 211 139-143. 

Acyl chlorides are prepared from acids and either SOCI2 or PCI5. They react rapidly with water to give acids, with alcohols to give esters, and with ammonia to give amides. 

Figure 4.1 GC/MS analysis of methyl esters prepared from a whole cell lipid extract of the YEpOLEX-PDesat-TnD11Z-transformed ole1 strain of Saccharomyces cerevisiae (A) total ion spectrum of fatty acid methyl esters resolved by capillary GLC (B) mass spectrum of the degradation products of the DMDS adduct of Z11 -16 Me in A. The diagnostic m/z values of the DMDS adduct of Z11-16 Me are labeled. (Reproduced with permission from Knipple et al., 1998. 1998 by The National Academy of Sciences.)...

Figure 4.4 GC/MS analysis of DMDS adducts of methyl esters prepared from whole cell lipid extracts of the YEpOLEX-PoctoZIO-transformed olel strain of S. cerevisiae (A) control olel yeast cells supplemented with 0.5 mM Z11 -18 Acid (B) YEpOLEX-PoctoZl0-transformed olel yeast cells supplemented with 0.05 mM Z11-18 Acid (C) mass spectrum of DMDS adduct of Z10-16 Me in B. GC peaks prior to 25 minutes in A and B correspond to saturated C10-C18 methyl esters. Peaks corresponding to DMDS adducts are found at 44 min for externally added Z11-18 Me and at 38 min in B for Z10-16 Me. (Reproduced with permission from Hao et al., 2002. 2002 by Insect Biochemistry and Molecular Biology.)...

Thiol esters have recently found broad applications in organic synthesis. Two methods for their preparation from acid chlorides and acids are described in the preparation of 2-METHYLPROPANE-2-THIOL ESTERS OF CYCLOHEXANECARBOXYLIC ACID AND CHOLIC ACID. Conversion of the former thiol ester to the corresponding O-t-butyl ester illustrates a general method for the preparation of O-ESTERS FROM THE CORRESPONDING THIOL ESTERS. 

Methyl esters prepared from undecylenic acid and containing an episulfide group were tested as inhibitors of JH III epoxide hydrolase activity to evaluate its biological role in insects <2005MI140>. 

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