Synthesis of highly substituted pyridines over zeolite molecular sieves under high pressure

Simple and selective single step synthesis of highly substituted pyridines (trisubstituted pyridines) from aliphatic aldehydes and aqueous ammonia using zeolite as a catalyst under high pressure (autogenous pressure) conditions with high conversion and moderate selectivity is presented. The catalyst can be reused many times without significant loss of activity. Graphical Abstract: An efficient novel protocol for the synthesis of 2,3,5-trisubstituted pyridines in single step is achieved using aliphatic aldehydes and aqueous ammonia over zeolites under high pressure (autogenous pressure) in batch process. The catalyst is inexpensive, reusable and the product isolation is simple and environmentally benign.[Figure not available: see fulltext.]