How is 1,2,3,6-tetrahydropyridine-4-carboxylic acid (CAS: 64603-90-3) typically synthesized?

1,2,3,6-Tetrahydropyridine-4-carboxylic acid can be synthesized via a multistep process starting with 1,2,3,6-tetrahydropyridine. This involves the condensation of 2-amino-1,3,6,7-tetrahydropyridine with a carboxylic acid chloride or anhydride. The reaction can be catalyzed by a Lewis acid such as aluminum chloride, with yields typically ranging from 60% to 80%. The process requires careful control of reaction conditions to achieve high selectivity.