An one-pot organo- and iodine sequential catalysis strategy for reactions of amides with pyrazole-based primaryamines was described to synthesize chiral α-amino amides with a quaternary stereocenter. This methodology exhibited strong asymmetric induction, resulting in a typical enantiomeric excess value exceeding 99% and diastereoselectivity up to >99:1 dr. Moreover, the reaction was conducted without
Catalyst free Michael addition of 3-methyl-2-pyrazolin-5-one to β-nitrostyrenes ‘on water’: a green protocol for facile synthesis of 4-(1-aryl-2-nitroethyl)-3-methyl-1H-pyrazol-5-ol
A highly efficient and green protocol has been developed for the synthesis of 4-(1-aryl-2-nitroethyl)-3methyl-1H-pyrazol-5-ol via Michael addition of 3-methyl-2-pyrazolin-5-one with beta-nitrostyrenes under catalyst free conditions on aqueous medium. A series of 4-(1-aryl-2-nitroethyl)-3-methyl-1H-pyrazol-5-ols have been synthesized with good to excellent yield. C-alkylated product was observed exclusively with 3-methyl-2-pyrazolin-5-one without formation of N-alkylated product. (C) 2013 Elsevier Ltd. All rights reserved.