Formate esters, reaction with aqueous

Reactions of the Side Chain. Benzyl chloride is hydrolyzed slowly by boiling water and more rapidly at elevated temperature and pressure in the presence of alkaHes (11). Reaction with aqueous sodium cyanide, preferably in the presence of a quaternary ammonium chloride, produces phenylacetonitrile [140-29-4] in high yield (12). The presence of a lower molecular-weight alcohol gives faster rates and higher yields. In the presence of suitable catalysts benzyl chloride reacts with carbon monoxide to produce phenylacetic acid [103-82-2] (13—15). With different catalyst systems in the presence of calcium hydroxide, double carbonylation to phenylpymvic acid [156-06-9] occurs (16). Benzyl esters are formed by heating benzyl chloride with the sodium salts of acids benzyl ethers by reaction with sodium alkoxides. The ease of ether formation is improved by the use of phase-transfer catalysts (17) (see Catalysis, phase-thansfer). 

Figure 22.28 and Figure 22.29 show, respectively, the H and C-NMR spectra of the oligoesters prepared from epoxidized sunflower oil methyl esters (methyl biodiesel from sunflower oil) and di-l,2-cyclohexanedicarboxylic anhydride using triethylamine as initiator. These materials are soluble in common organic solvents such as acetone, ethanol, tetrahydrofurane, and chloroform, but insoluble in water. Oligoesters from epoxidized biodiesel can be used as intermediate materials for the synthesis of polyelectrolytes by saponification reactions with aqueous solution of sodium or potassium hydroxide at room temperature (Fig. 22.27). The products obtained after saponification present solubility in water. Amphiphilic materials, such as the polyelectrolytes prepared from epoxidized biodiesel, have hydrophobic and hydrophilic segments. They can spontaneously self-organize in a wide variety of structures in aqueous solution. Understanding the dynamics of the formation and transition between the various self-organized structures is important for technological applications.

Aldehydes were converted into the corresponding esters by initial dithian formation, metallation, reaction with dimethyl disulphide, and finally hydrolysis of the 2-thiomethyl-l,3-dithians so obtained with HgClj-HgO in aqueous alcohols.The yields of methyl or ethyl esters were high but attempts to prepare t-butyl esters by this route failed and produced only acids in moderate yield. Thiomethylation or deuteriation of the allylic lithio-salt (113) occurred exclusively a to sulphur. Dithianyl carbanions... 

N-Acylation is readily carried out by reaction of the alkaU metal salts with the appropriate acid chloride. C-Acylation of pyrroles carrying negative substituents occurs in the presence of Friedel-Crafts catalysts. Pyrrole and alkylpyrroles can be acylated noncatalyticaHy with an acid chloride or an acid anhydride. The formation of trichloromethyl 2-pyrryl ketone [35302-72-8] (20, R = CCI3) is a particularly useful procedure because the ketonic product can be readily converted to the corresponding pyrrolecarboxyUc acid or ester by treatment with aqueous base or alcohoHc base, respectively (31). 

Ba.sic Hydrolysis. Throughout most of history, soap was manufactured by boiling an ester with aqueous alkaU. In this reaction, known as saponification, the ester is hydroly2ed with a stoichiometric amount of alkaU. The irreversible formation of carboxylate anion drives the reaction to completion. 

The catalytic conditions (aqueous concentrated sodium hydroxide and tetraalkylammonium catalyst) are very useful in generating dihalo-carbenes from the corresponding haloforms. Dichlorocarbene thus generated reacts with alkenes to give high yields of dichlorocyclopropane derivatives,16 even in cases where other methods have failed,17 and with some hydrocarbons to yield dicholromethyl derivatives.18 Similar conditions are suited for the formation and reactions of dibromocar-benc,19 bromofluoro- and chlorofluorocarbene,20 and chlorothiophenoxy carbene,21 as well as the Michael addition of trichloromethyl carbanion to unsaturated nitriles, esters, and sulfones.22... 

Method B The chloroalkane or a,w-dichloroalkane (0.1 mol) and HC02Na (13.6 g, 0.2 mol for the chloroalkane, 27.2 g, 0.4 mol for the a,co-dichloroalkane) are stirred with TBA-Br (1.61 g, 5 mmol) until the reaction is complete (Table 3.16). H20 (10 ml) is added to the cooled mixture. The organic phase is separated, dried (MgS04), and fractionally distilled to yield the formate ester. When aqueous NaOH (50%, 4.5 ml) is added dropwise over 30 min to the vigorously stirred reaction mixture, the alcohol (diol) is formed, which can be isolated by extraction from the reaction mixture with butanone (2 x 20 ml) and fractional distillation. 

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