“…␣-Methylproline (2, racemic [23]), 1,2,3,6-tetrahydropyridine-2-carboxylic acid (3, baïkaïne, enantiopure L [20]; d-isomer was produced via the partial racemization of l-baïkaïne by refluxing in 2 M NaOH), piperidine-2-carboxylic acid (4, pipecolic acid, Pip, enantiopure l and d [21]), 4-hydroxypipecolic acid {5, enantiopure (2S,4R) [20]; racemic [24]}, 5-hydroxypipecolic acid {6, enantiopure (2S,5R) [20]; racemic [25]}, 5-methylpiperazine-2-carboxylic acid (8, racemic [26]), morpholine-3-carboxylic acid (9, enantiopure L [21]; racemic [27]), thiomorpholine-3-carboxylic acid (10, enantiopure L [22]; racemic [28]) were synthetized by using the indicated reported literature methods.…”