178755-12-9

Upstream product

• 178755-10-7 dimethyl (2S,3R)-N-benzyl-3-methyl-N-(9-phenylfluoren-9-yl)aspartate 
• 55135-66-5 9-bromo-9-phenyl-9H-fluorene 
• 178755-19-6 2-benzylaminosuccinic acid dimethyl ester 
• 146512-92-7 dimethyl L-N-benzyl-N-(9-phenylfluoren-9-yl)aspartate 

Downstream Products

• 127199-52-4 (3S,4S)-1-benzyl-3-(tert-butoxycarbonyl)amino-4-methylpyrrolidine 
• 127199-54-6 (3S,4S)-3-(tert-Butoxycarbonyl)amino-4-methylpyrrolidine 
• 149598-21-0 (2S,3R)-2-(tert-butoxycarbonyl)amino-3-methylbutane-1,4-diol 

Relevant academic research and scientific papers

Quinoline carboxylic acid

5-Amino-7-((3S,4S)-3-amino-4-methyl (or ethyl)-1-pyrrolidinyl)-1-cyclopropyl-6-fluoro-1,4-dihydro-8-methyl-4-oxoquinoline-3-carboxylic acid or a pharmacologically acceptable salt thereof represented by the following formula wherein asymmetric carbon atoms

A large-scale preparation of (3S,4S)-3-(tert-butoxycarbonyl)amino-4-methylpyrrolidine and its analogs from L-aspartic acid

(3S,4S)-3-(tert-Butoxycarbonyl)amino-4-methylpyrrolidine (12a) was synthesized from L-aspartic acid (4) on a large scale. Methylation of dimethyl (2S)-N-benzyl-N-(9-phenylfluoren-9-yl)aspartate (5), easily derived from 4, with methyl iodide gave (3R)-3-methylaspartate (6a) in 91% yield with high diastereoselectivity. Reduction of 6a with lithium aluminum hydride, followed by hydrogenolysis, protection with di-tert-butyl dicarbonate, and mesylation gave 10a in 89% overall yield. Subsequently, reaction of 10a with benzylamine under a nitrogen atmosphere at room temperature, followed by hydrogenolysis, gave the target compound (12a) in 65% overall yield. In a similar manner to that described for the preparation of 12a from 5, compound 5 was converted into 4-ethyl and 4-propyl derivatives (12b,c) in 34% and 38% overall yields.