Ammonium chloride-promoted four-component synthesis of pyrrolo[3,4-b]pyridin-5-one.
A novel multicomponent synthesis of 5-aminooxazole starting from simple and readily available inputs is described. Thus, simply heating a methanol solution of an aldehyde 3, an amine 4, and an alpha-isocyanoacetamide 5 provided the 5-aminooxazole (1) in good to excellent yield. The reaction of 1 with alpha,beta-unsaturated acyl chloride 13 lead to the formation of pyrrolo[3,4-b]pyridin-5-one (2) in a single operation. A triple domino sequence, acylation/IMDA/retro-Michael cycloreversion, is involved in this new scaffold-generating reaction. After the observation that ammonium chloride can significantly accelerate the oxazole formation in toluene, a one-pot four-component synthesis of 2 is developed.
Janvier
Pierre
P
Institut de Chimie des Substances Naturelles, CNRS, 91198 Gif-sur-Yvette, France.
Sun
Xiaowen
X
Bienaymé
Hugues
H
Zhu
Jieping
J
D000643:Ammonium Chloride / Q000737:chemistry*; D001393:Azoles / Q000138:chemical synthesis; D011725:Pyridines / Q000138:chemical synthesis*; D011758:Pyrroles / Q000138:chemical synthesis*
D001393:Azoles; D011725:Pyridines; D011758:Pyrroles; D000643:Ammonium Chloride