Chichibabin “isodesmopyridine” synthesis

An efficient and scalable synthesis of Isodesmosine

“…The solvent was evaporated at reduced pressure to get the residue, which was purified by flash column chromatography on silica gel using 10% ethyl acetate in n-hexane to afford 6-(tert-butyl)-1-methyl(S,E)-5-((tert-butoxycarbonyl) amino) hex-2-enedioate 13 as white solid (7.8 g, 23.7 mmol, 79% yield over two steps). 1 H NMR (300 MHz, CDCl 3 ): δ 6.89-6.79 (m, 1H),…”

“…Isodesmosine is pyridinium‐based compound bearing four lysine amino acid moieties at 1,2,3,5‐ position [1]. Isodesmosine is found in elastin which is the key component of elastic fiber.…”

“…Elastin found to be present in extracellular matrix, is an insoluble protein located which plays a vital role in producing resilience of internal organs, the elasticity, and tissues such as tendons, ligaments, arteries, lungs, and skin [2,3]. Elastin comprises of dissolvable antecedent tropoelastin monomers crosslinked extracellularly by amino acids generating two amino acid isoforms [4] that is, Desmosine (1) and Isodesmosine (2) along with other pyridinium polyfunctional cross-links such as Isodesmopyridine [5] (3) and Desmopyridine [5] (4), Neodesmosine [6] (5) (Figure 1). Their contents may be used to estimate the quantitative insoluble elastin formation [7].…”

“…Their contents may be used to estimate the quantitative insoluble elastin formation [7]. Biosynthesis of these pyridinium-based compounds usually occurs through Chichibabin pyridine synthesis using dehydrolysinoleucine and allysine [1].…”