From inorganic esters

Strictly speaking the alkyl halides are esters of the halogen acids, but since they enter into many reactions (t.g., formation of Grignard reagents, reaction with potassium cyanide to yield nitriles, etc.) which cannot be brought about by the other eaters, the alkyl halides are usually distinguished from the esters of the other inorganic acids. The preparation of a number of these is described below. 

The first successhil attempt to make textile fibers from plant cellulose can be traced to George Audemars (1). In 1855 he dissolved the nitrated form of cellulose in ether and alcohol and discovered that fibers were formed as the dope was drawn into the air. These soft strong nitrocellulose fibers could be woven into fabrics but had a serious drawback they were explosive, nitrated cellulose being the basis of gun-cotton (see Cellulose esters, inorganic esters). 

Another problem arises from brominated aromatic species derived from inorganic bromides used as oxidation cocatalysts. As a result, the cmde NDA is converted to its dimethyl ester, DMNDA [840-65-3] and solvent recrystalHzed to give a high purity diester (36—38). A process for purifying NDA directly by hydrogenation (pure TA process) has also been described (39). 

Alcohols form esters from inorganic acids as shown above. Like all esterifications, these reactions are reversible that is, in the presence of water and the right conditions, they revert to the original alcohol and acid. Nitrate esters are mainly used as explosives, but some have found use as diesel fuel additives. Note the difference between a nitrate ester such as ethyl nitrate (C2H5ONO2) and an organic nitro compound such as nitroethane (C2H5NO2). 

The most widely used inorganic ester of cellulose is cellulose nitrate (CN), also called nitrocellulose or gun cotton. Celluloid is produced from a mixture of CN and camphor. It was first made in 1833 when cellulose-containing linen, paper, or sawdust was reacted with concentrated nitric acid. It was the first synthetic cellulose product that was recognized. Initially, CN was used as a military explosive and improvements allowed the manufacture of smokeless powder. A representation of CN is given in structure 9.7. 

Flexographic inks -cellulose nitrate m [CELLULOSE ESTERS - INORGANIC ESTERS] (Vol 5) -dispersed pigment [PIGMENT DISPERSIONS] (Vol 18) -fluorescent pigments m [LUMINESCENT MATERIALS - FLUORESCENT PIGMENTS (DAYLIGHT)] (Vol 15) -from triarylmethane dyes [T RIPHENYLMETHANE AND RELATED DYES] (Vol 24)... 

This reaction is rapid and produces few side reaction products. In addition, the sulfur dioxide and hydrogen chloride formed as byproducts are gasses and therefore easily removed from the reaction. Mechanistically, the alcohol initially reacts to form an inorganic ester. 

We shall show you the mechanism of the cleavage, because it leads us nicely into the next chapter. The first step is rather like the first step of many oxidations—formation of an inorganic ester (here a periodate), The periodate can form a cyclic ester by attack on the carbonyl group. Next, we can push thetarrows round the ring to reduce the iodine from I(VII) to I(V), cleave the double bond, and generate acetone and the acid. 

Esters or ethereal salts are derivatives of alcohols formed by the reaction of an alcohol with an acid. As they are thus acid derivatives also and as the more important esters are those formed from the organic acids, which we shall soon study, the chief discussion of them as a group will come later. There are, however, to be considered the esters formed from inorganic acids and these will be presented now. The chemical properties of alcohol in its relation to both bases and acids are of especial interest and importance. We have spoken of the fact that alcohol as an hydroxyl compound belongs to the water type, and that the other representatives of this type are the metal hydroxides or bases, and the non-metal hydroxides or acids. 

A survey of work since 1975 on the derivatization of ascorbic acid is reviewed from the perspective of the organic chemistry of ascorbic acid. Recent advances in the control of regioselectivity of alkylative derivatization of ascorbic acid have been made possible by the utilization of di- and trianions of ascorbic acid. Their use has allowed the facile synthesis of inorganic esters of ascorbic acid. New synthesis of acetal and ketal, side-chain oxidized, and deoxy derivatives are reviewed. The total synthesis of a new side-chain oxidized ascorbic acid derivative, 5-ketoascorbic acid, is reported. 

Removal of a second proton from the C-2 hydroxyl fpAa= 11.79) produces a dianion which reacts preferentially at the more reactive oxygen on C-2 allowing selective alkylation/acylation at this position (Figure 4.12). A similar approach can be employed to synthesise selectively certain 2-0-inorganic esters such as the 2-0-sulphate. If both the C-2 and C-3 hydroxy-groups are protected, then base-promoted alkylation or acylation takes place at the more sterically accessible primary hydroxyl on C-6 rather than C-5, reaction at this latter position occurring only after derivatisation of the other three (Figure 4.13). 

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