
TY  - JOUR
A1  - Andreatta, RH 
A1  - Nair, V 
A1  - Robertson, AV 
A1  - Simpson, WRJ 
T1  - Synthesis of the <I>cis</I> and <I>trans</I> isomers of 4-Chloro-L-proline, 4-Bromo-L-proline, and 4-Amino-L-proline
JF  - Australian Journal of Chemistry
JO  - Aust. J. Chem.
Y1  - 1967
VL  - 20
IS  - 7
SP  - 1493
EP  - 1509
KW  - 
UR  - https://doi.org/10.1071/CH9671493 
N2  - cis- and trans-4-Chloro- and 4-bromo-L-prolines have been synthesized stereospecifically, the key step being SN2 displacement of a free or substituted 4-hydroxyl group in suitably protected 4-hydroxy-L- prolines. Similar displacements with azide ion followed by reduction provide convenient routes to cis- and trans- 4-amino-L-proline. A less satisfactory pathway to cis-4-aminoproline is reduction of a 4- oximinoproline derivative. In the course of the syntheses, which involve a variety of protecting groups, 45 new L-proline derivatives have been prepared. Unexpected side reactions were the formation of cis-4-hydroxyprolinamide by the action of ammonia on trans-4- bromoproline, and the reduction by sodium borohydride of N- benzyloxycarbonyl-4-oximinoproline methyl ester to N-benzyloxycar- bonyl-4-oximinoprolinol. 
ER  -

