| 摘要 |
<p>Parent patent described the prepn. of 5-cyano valeric acid esters by reacting a pentene nitrile of formula R'-CH2-CN (I) (where R' is MeCH=CH- or CH2=CH-CH2-) with CO and an OH-contg. cpd. of formula R2-OH (II) where R2 is an aliphatic, cycloaliphatic or aromatic gp.) at >=140 degrees C and at >=100 bar in the presence of metal carbonyls and basic 5- or 6-membered N contg. monocyclic heterocyclic cpds. In this addn. 4-cyanovaleric acid esters (III) are prepd. by a similar process using 2-methyl-3-butene nitrile (I') as the pentene nitrile. Also claimed are 4-cyanovaleric acid esters of formula R2O-CO-CH2-CH2-CH(CN)-Me (IIIa) (where R2 is 2C or >2C aliphatic gp.; or 2C alkyl substd. with a heteroatom or a cycloaliphatic, araliphatic or aromatic gp.). (III) are intermediates in the prepn. of dyes, pest control agents, fibres (esp. polyamide fibres) and plastics. (III) can be hydrogenated to 4-methyl-5-aminovalerates, which on elimination of the alcohol give 5-methyl-2-piperidone, which can be used as an extractant and as a solvent, and is also an intermediate in the prodn. of nicotinic acid. (III) can be obtd. in better yields and purity, esp. on an industrial scale. Toxic, difficult to handle cpds. such as NaCN are avoided and the reaction is less harmful to the environment. There is no need for an esterification step.</p> |
