Pipecolinic acid, methyl

The resulting 2,6-xylidide a-pipecolinic acid (2.2.5) is methylated to mepivacaine using formaldehyde with simultaneous reduction by hydrogen in the presence of platinum on carbon catalyst [15]. 

Decarboxylation with concomitant dehydrogenation occurred in some cyclic amino acids. For example, (I)-proline was converted into a mixture of 1-pyrroline and its trimer. The methyl ester of (L)-proline was simply dehydrogenated to its /i-imine (69%). With two equivalents of IOB in chloroform (L)-proline was converted directly into 2-pyrrolidinone (70%). This transformation was less efficient for pipecolinic acid and ( )-pyrrolidinone-5-carboxylic acid [48]. 

Cyclocondensation of pipecolinic acid and malic acid anhydride in pyridine afforded 3-hydroxy-2,3-dimethylperhydropyrido[l,2-a]pyrazine-l, 4-dione (74CB2804). Cyclocondensation of bis(2,4,6-trichlorophenyl) mal-onates with 2-methyl-, 2-benzyl- and 2-ethoxycarbonylmethylquinoxalines and -3-ones at 250°C afforded 8-hydroxy-10//-pyrido[l,2-a]quinoxalin-10-ones and their 5,6-dihydro-6,10-dione derivatives (77M103). Under Horner-Wittig reaction conditions, the reactions of 2-formylquinoxaline and dialkyl phosphonosuccinates (314) also involved cyclization to give alkyl 10-oxo-10//-pyrido[l,2-a]quinoxahne-8-carboxylate (80LA542). 

The hydroboration of ( )-baikiain (4,5-dehydro-( )-pipecolinic acid) via its JV-benzyloxycarbonyl methyl ester derivative (134) led, after oxidation and removal of the protecting groups, to 72% trans-5-hydroxy-( + )-pipecolinic acid (136) and 28% (raw.s-4-hydroxy-( + )-pipecolinic acid (135), separable by preparative ion-exchange column chromatography.118... 

Lys Methyl linoleate Diaminopentane, aspartic acid, glycine, alanine, a-aminoadipic acid, pipecolinic acid, 1,10-diamino-1,10-dicarboxydecane... 

Electrolytic reduction using a lead cathode in 20% sulfuric acid converted pyridine a-carboxaldehyde to a mixture of 41% of a-picoline, 25% of a-pipecoline and 11% of 2-methyl-1,2,3,6-tetrahydropyridine [443]. 

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