187986-71-6

Upstream product

• 187986-70-5 4-(3-hydroxypropyl)-3,5-dimethyl-4-(3-oxopropyl)-1H-pyrrole-2-carboxylic acid ethyl ester 
• 98-59-9 p-toluenesulfonyl chloride 
• 54278-10-3 ethyl 5-(ethoxycarbonyl)-2,4-dimethyl-1H-pyrrole-3-propanoate 
• 37789-64-3 4-(2-carboxyethyl)-3,5-dimethyl-1H-pyrrole-2-carboxylic acid ethyl ester 

Downstream Products

• 4758-64-9 ethyl 3,5-dimethyl-4-propylpyrrole-2-carboxylate 

Relevant academic research and scientific papers

Heteronuclear NOE analysis of bilirubin solution conformation and intramolecular hydrogen bonding

1H{1H}-Homonuclear and 13C{1H}-heteronuclear NOE (Nuclear Overhauser Effect) experiments carried out on bilirubin analogs (1-5) in CDCl3 and in CDCl3-(CD3)2SO solutions indicate that the carboxylic acid groups and dipyrrinone lactams and/or pyrroles are linked by intramolecular hydrogen bonding. Nonbonded C-H to H-C and N-H to H-N, and N-H to CO2H distances were calculated from the NOE data and confirm that the bilirubins adopt a folded, ridge-tile shape in solution.

Enantioselection in bilirubin analogs with only one propionic acid group

Enantiopure synthetic bilirubin analogs (1 and 2) with only a single β- methyl propionic acid group adopt a folded, ridge-tile conformation stabilized by intramolecular hydrogen bonding. The β-methyl group forces the pigment to adopt a left-handed (M) helical conformation, as evidenced by exciton circular dichroism spectra and indicating that one propionic acid group is sufficient to control the pigment's conformation.