A new synthesis of amino acid-based enantiomerically pure substituted 2,3,4,4a,5,6-hexahydro-1H-pyrazino[1,2-a]quinoxalines.
A new series of enantiomerically pure 2,3,4,4a,5,6-hexahydro-1H-pyrazino[1,2-a]quinoxalines were synthesized for the first time in twelve steps from 1-fluoro-2-nitrobenzene and S-amino acids with 13-20% overall yields. First use of intramolecular Mitsunobu cyclization for 1,2,3,4-tetrahydroquinoxalines followed by PPh(3)/I(2)/imidazole mediated 6-exo-tet cyclization were the key steps.
Samanta
Krishnananda
K
Medicinal and Process Chemistry Division, Central Drug Research Institute, Lucknow, 226001, UP, India.
Panda
Gautam
G
D000596:Amino Acids / Q000737:chemistry*; D003500:Cyclization; D009578:Nitrobenzenes / Q000737:chemistry; D011810:Quinoxalines / Q000138:chemical synthesis*; D013237:Stereoisomerism
D000596:Amino Acids; D009578:Nitrobenzenes; D011810:Quinoxalines; C046306:1-fluoro-2-nitrobenzene