title: First nucleophilic aromatic substitution of annelated pyrazole.
abstract: 3-Chloropyrazolo[3,4-c]quinoline 5, 3-chloropyrazolo[3,4-c]isoquinoline 6, 1,2-dihydro-1,2-dimethylpyrazolo[3,4-c]quinolin-3-one 8, and 1,2-dihydro-1,2-dimethylpyrazolo[3,4-c]isoquinolin-3-one 10 were obtained by acid-induced nucleophilic aromatic substitution (S(N)H) of H-3 in N-hydroxypyrazolo[3,4-c]quinoline 1b and in N-hydroxy pyrazolo[3,4-c]isoquinoline 3b. In the acid-induced chlorination, 3b was far more reactive than 1b, whereas the related N-hydroxypyrazolo[4,3-c]quinoline 2b and N-hydroxypyrazolo[4,3-c]isoquinoline 4b were completely unreactive toward S(N)H under identical conditions.
authors.affiliation: Department of Medicinal Chemistry, The Royal Danish School of Pharmacy, Universitetsparken 2, DK-2100 Copenhagen, Denmar.
authors.forename: Jan
authors.initials: J
authors.lastname: Pawlas
authors.forename: Per
authors.initials: P
authors.lastname: Vedsø
authors.forename: Palle
authors.initials: P
authors.lastname: Jakobsen
authors.forename: Per O
authors.initials: PO
authors.lastname: Huusfeldt
authors.forename: Mikael
authors.initials: M
authors.lastname: Begtrup