Enantioselective synthesis of (R)- and (S)-2-methyl-3-oxo-3,4-dihydro-2H-1,4-benzoxazine-2-carboxamides
摘要:
Enantiomers of 2-methyl-3-oxo-3,4-dihydro-2H-1,4-benzoxazine-2-carboxamides bearing different substituents in the aromatic ring are obtained by the cyclization of (R)-monomethyl 2-methyl-2-(2-nitrophenoxy)malonates with the participation of the carboxy and methoxycarbonyl group, respectively. (C) 1998 Elsevier Science Ltd. All rights reserved.
Stereoselective synthesis of (R)- and (S)-2-methyl-3-oxo-3,4-dihydro-2H-1,4-benzoxazine-2-carboxylic acids, -carboxylates and -carboxamides
摘要:
(R)-Monomethyl 2-methyl-2-(2- nitrophenoxy)malonates obtained by PLE catalyzed hydrolysis of the corresponding dimethyl malonates undergo solvent-dependent enantioselective cyclization to afford (R)-methyl 2-methyl-3-oxo-3,4-dihydro-2H-1,4-hentoxazine-2-carboxylates and (S)-2-methyl-3-oxo-3,4-dihydro-2H-1,4-benzoxazine-2-carboxyIic acids, respectively. These compounds are easily converted to enantiomerically and diastereomerically pure carboxamides, which are used as peptidomimetic building blocks. (C) 1999 Elsevier Science Ltd. All rights reserved.