Synthesis of functionalized pyridazin-3(2H)-ones via bromine-magnesium exchange on bromopyridazin-3(2H)-ones.
The potential of halogen-magnesium exchange reactions, followed by quenching with electrophiles, for the functionalization of the pyridazin-3(2H)-one core was investigated. 2-Benzyl-4-bromo-5-methoxy- (1), 2-benzyl-5-bromo-4-methoxy- (4), and 2-benzyl-4,5-dibromopyridazin-3(2H)-one (10) were selected as readily available model substrates. While 1 and 10 gave exclusively C-4 metalation, a tandem reaction involving nucleophilic substitution via addition elimination and bromine-magnesium exchange was observed with 4.
Ryabtsova
Oxana
O
Organic Synthesis, Department of Chemistry, University of Antwerp, Groenenborgerlaan 171, B-2020 Antwerp, Belgium.
Verhelst
Tom
T
Baeten
Mattijs
M
Vande Velde
Christophe M L
CM
Maes
Bert U W
BU
D001966:Bromine / Q000737:chemistry*; D006842:Hydrocarbons, Brominated / Q000737:chemistry*; D008274:Magnesium / Q000737:chemistry*; D008956:Models, Chemical; D011724:Pyridazines / Q000138:chemical synthesis* / Q000737:chemistry; D011728:Pyridones / Q000737:chemistry*
D006842:Hydrocarbons, Brominated; D011724:Pyridazines; D011728:Pyridones; D008274:Magnesium; D001966:Bromine