Efficient and scaleable methods for omega-functionalized nonanoic acids: Development of a novel process for azelaic and 9-aminononanoic acids (nylon-6,9 and nylon-precursors)

A new, convergent synthesis and process of the title open-chain C-9 compoun ds, valuable monomers for preparation of polyamides with specific propertie s, are discussed, Starting from relatively inexpensive ram materials, for e xample, cyclohexanone and activated C-3 olefins, the method provides polyme r grade omega -functionalized nonanoic acids. An improved protocol for cyan oethylation or carbalkoxyethylation of cyclohexanone in the presence of a c atalytic amount of primary or secondary amines gave 3-(2-oxo-cyclohexane) p ropanecarboxylic acid derivatives 1 in high yield, Cyclohexaneperoxycarboxy lic acid (CHPCA) is introduced as highly efficient reagent in Baeyer-Villig er rearrangement of 1, Pyrolysis of 2 (EWG = CN) afforded under optimized c onditions 3 in high yield and regioisomeric purity, otherwise a mixture of three unsaturated isomeric co-cyano nonenoic acids is obtained, Partial hyd rogenation of unsaturated acids 3 allowed isolation of saturated long chain difunctionalized acids 4, Hydrolysis of 4 led to 1,9-nonancdicarboxylic ac id (azelaic acid) 5, whereas its hydrogenation at elevated pressure gave 9- aminononanoic acid 6, Alternatively, a practical four-step syntehsis of 5 v ia isolable 7-substituted oxepan-2-one (EWG =COOMe) 2 has been designed and experimentated, The versatile position of 3-(2 oxo-cyclohexane) propanecar boxylic acid derivatives 1 as ram materials for Fine Chemicals is also disc ussed.