title: An expedient approach to 1,2-dihydroisoquinoline derivatives via cobalt catalysed 6-endo dig cyclization followed by Mannich condensation of o-alkynylarylaldimines.
abstract: A highly effective 6-endo dig cyclisation of o-alkynylaldimines to 1,2-dihydroisoquinolines has been described via direct and nitro Mannich condensation using inexpensive and readily available cobalt chloride as catalyst. This strategy provides an effective procedure for the synthesis of substituted 1,2-dihydroisoquinolines derivatives in moderate to high yields. An addition of pronucleophiles, such as nitromethane, acetone and α-hydroxyacetone, to o-alkynylarylaldimines has been achieved via isoquinolinium intermediate.
authors.affiliation: Chemical Biology Research Laboratory, Department of Chemistry, University of Delhi, Delhi-110007, India.
authors.lastname: Urvashi
authors.forename: Gaurav K
authors.initials: GK
authors.lastname: Rastogi
authors.forename: Sandeep K
authors.initials: SK
authors.lastname: Ginotra
authors.forename: Alka
authors.initials: A
authors.lastname: Agarwal
authors.forename: Vibha
authors.initials: V
authors.lastname: Tandon
mesh_terms: D000480:Alkynes / Q000737:chemistry*; D000588:Amines / Q000737:chemistry; D002384:Catalysis; D003035:Cobalt / Q000737:chemistry*; D003500:Cyclization; D007546:Isoquinolines / Q000737:chemistry*; D007700:Kinetics; D008958:Models, Molecular; D008968:Molecular Conformation; D013237:Stereoisomerism
chemical_list: D000480:Alkynes; D000588:Amines; C109853:G 1617; D007546:Isoquinolines; D003035:Cobalt