title: Synthesis of withasomnines and their non-natural analogues from aldehydes and 4-nitro-1-butanol in three steps.
abstract: Total synthesis of all three pyrazole-based withasomnine alkaloids and selected examples of their non-natural analogs has been achieved from readily available aldehydes and 4-nitro-1-butanol in three steps. Since 4-nitro-1-butanol in turn is prepared in two steps via Michael addition of nitromethane to acrylate followed by borane reduction of the ester group and the key 1,3-dipolar cycloaddition step is carried out with commercially available TMSCHN2, this approach is a very convenient and economical one.
authors: Department of Chemistry, Indian Institute of Technology, Bombay, Mumbai 400 076, India.
authors: Deepti
authors: D
authors: Verma
authors: Rahul
authors: R
authors: Kumar
authors: Irishi N N
authors: IN
authors: Namboothiri
mesh_terms: D000447:Aldehydes / Q000737:chemistry*; D000440:Butanols / Q000737:chemistry*; D003500:Cyclization; D015394:Molecular Structure; D009574:Nitro Compounds / Q000737:chemistry*; D011720:Pyrazoles / Q000138:chemical synthesis* / Q000737:chemistry
chemical_list: D000447:Aldehydes; D000440:Butanols; D009574:Nitro Compounds; D011720:Pyrazoles; C568582:withasomnine