185142-04-5

Basic information

• Product Name: L-Glutamic acid, 4-(2,2-dimethyl-1-oxopropyl)-N-(9-phenyl-9H-fluoren-9-yl)-, 5-methyl ester
• CAS NO: 185142-04-5
• Molecular Formula: C30H31NO5
• Molecular Weight: 485.58
• Mol File: 185142-04-5.mol
• Article Data: 2

Chemical Properties

• CAS DataBase Reference: L-Glutamic acid, 4-(2,2-dimethyl-1-oxopropyl)-N-(9-phenyl-9H-fluoren-9-yl)-, 5-methyl ester(CAS DataBase Reference)
• NIST Chemistry Reference: L-Glutamic acid, 4-(2,2-dimethyl-1-oxopropyl)-N-(9-phenyl-9H-fluoren-9-yl)-, 5-methyl ester(185142-04-5)
• EPA Substance Registry System: L-Glutamic acid, 4-(2,2-dimethyl-1-oxopropyl)-N-(9-phenyl-9H-fluoren-9-yl)-, 5-methyl ester(185142-04-5)

Safety Data

• Hazardous Substances Data: 185142-04-5(Hazardous Substances Data)

Upstream product

• 3282-30-2 pivaloyl chloride 
• 119595-72-1 L-N-(9-(9-phenylfluorenyl))glutamic acid γ-methylester 

Downstream Products

• 185142-08-9 methyl 6,6-dimethyl-5-oxo-2-[N-(9-(9-phenylfluorenyl))amino]heptanoate 
• 185142-15-8 (2S,5R)-N-(tert-butyloxycarbonyl)-5-tert-butylproline 
• 185142-33-0 (S)-6,6-Dimethyl-5-oxo-2-(9-phenyl-9H-fluoren-9-ylamino)-heptanoic acid methylamide 
• 185142-06-7 (S)-6,6-Dimethyl-5-oxo-2-(9-phenyl-9H-fluoren-9-ylamino)-heptanoic acid 
• 163685-22-1 (S)-2--3-(3-tert-butyl-5-oxo-2H-isoxazol-4-yl)propionic acid 

Relevant articles and documents

5-tert-butylproline

Steric effects on the isomer equilibrium of amides N-terminal to proline can be explored with 5-alkylprolines having bulky 5-position substituents. Enantiopure 5-tert-butylprolines were thus synthesized from glutamic acid via an acylation/diastereoselective reductive amination sequence. Double deprotonation of γ-methyl N-(PhF)glutamate (2) with LiN(SiMe3)2 and C-acylation with pivaloyl chloride provided β-keto ester 3, which upon γ-ester hydrolysis and decarboxylation gave δ-oxo-α-[N-(PhF)amino]heptanoic acid (4). Syntheses of (2S,5R)- and (2R,5S)-N-(BOC)-5-tert-butylprolines ((2S,5R)-1 and (2R,5S)-1) were accomplished by catalytic hydrogenation of their respective (2S)- and (2R)-methyl δ-oxo-α-[N-(PhF)amino]heptanoates ((2S)-5a and (2R)-5a) in methanol with di-tert-butyl dicarbonate followed by chromatography and ester hydrolysis with potassium trimethylsilanolate. The 5-tert-butylproline cis-diastereomers were proven to be of >99% enantiomeric purity after their conversion to diastereomeric α-methylbenzylamides 10. Good diastereoselectivity in favor of the trans-diastereomer was observed when (2S,5S)-5-tert-butylproline was synthesized from (2S)-δ-oxo-α-[N-(PhF)amino]heptanoate ((2S)-4) by solvolysis of the PhF group in trifluoroacetic acid and subsequent reduction of 5-tert-butyl-Δ5-dehydroproline (11) with tetramethylammonium triacetoxyborohydride; however, imino acid 11 was shown to be configurationally labile and racemized under acidic conditions. 5-tert-Butyl-Δ5-dehydroproline N'-methylamide 15 was configurationally stable in acid, yet preliminary attempts to reduce 15 favored cis-diastereomer 16. Alternatively, enantiopure trans-diastereomer, (2R,5R)-methyl N-(BOC)-5-tert-butylprolinate (9) was prepared by epimerization of (2S,5R)-9. In summary, this synthetic methodology now provides access to all four enantiopure 5-tert-butylproline isomers from inexpensive L- and D-glutamate as chiral educts.