Ethyl pyridine-3-carboxylate nicotinate

Esters of pyridine-carboxylic acids react normally with compounds containing activated methylene groups. The reactions are valuable, for example as routes to acylpyridines. The ethoxide-catalysed condensation of ethyl pyridine carboxylates with ethyl acetate has often been described early work suggested that esters of nicotinic acid gave lower yields than their isomers, but this is not so . Many esters other than ethyl acetate have been used and a number of substituted pyridine esters > Condensations with picolines to give desoxypyridoins are of practical value (p. 380). 

Ethyl nicotinate (ethyl pyridine-3-carboxylate). Reflux a mixture of 37 g (0.3 mol) pure nicotinic acid (Expt 6.150), 92 g (115 ml, 2 mol) of absolute ethanol and 90 g (50 ml) of concentrated sulphuric acid on a steam bath. Cool the solution and pour it slowly and with stirring on to 200 g of crushed ice. Add sufficient ammonia solution to render the resulting solution strongly alkaline generally, some ester separates as an oil but most of it remains dissolved in the alkaline solution. Extract the mixture with five 25 ml portions... 

Alkylpyridines can be oxidized to give pyridine carboxylic acids by a number of methods. For instance, nicotinic acid 114 is produced commercially by oxidation of 5-ethyl-2-methylpyridine 115 with HNO3, followed by selective thermal decarboxylation of the dicarboxylic acid 116 [60]. Selective side-chain oxidation is also possible, as shown in the examples 117 and 118 ... 

Nicotinic acid (pyridine-3-carboxylic acid), mp 236°C, was first obtained by oxidation of the alkaloid nicotine by KMn04. It is produced commercially from 5-ethyl-2-methylpyridine (see p 291). Nicotinic acid and its amide belong to the B group of vitamins (vitamin B5). The daily requirement of an adult is ca. 20 mg. Deficiency of nicotinic acid causes pellagra, a skin disease. 

Some data for pyrrole derivatives in beer are given in Table 22.16 and the occurrence of pyridine derivatives is noted in Tables 14.7 and 22.15. One pyridine derivative is noteworthy pyridine-3-carboxylic acid (nicotinic acid) is a B-vitamin essential for human growth. Beer contains 4500-86(X) ppb and about 15(X) ppb of ethyl nicotinate. Traces of the methyl, 3-methylbutyl, and phenethyl esters of nicotinic acid are also present in beer [91]. Ethyl nicotinate and o-aminoacetophenone, also present in beer (10 ppb), have also been associated with stale grainy flavours in beer at 2000 and 5 ppb respectively [92]. The level of some amides in beer is given in Table 22.17 [91]. Most... 

Pyridine-3-carboxylic acid ethyl ester (ethyl nicotinate)... 

Nicotinic acid (pyridine-3-carboxylic acid), mp 236 °C, was first obtained by oxidation of the alkaloid nicotine by KMn04. It is produced commercially from 5-ethyl-... 

---