title: Regioselective sulfonylation and N- to O-sulfonyl migration of quinazolin-4(3H)-ones and analogous thienopyrimidin-4(3H)-ones.
abstract: The sulfonylation of quinazolin-4(3H)-ones and related tetrahydrobenzothieno[2,3-d]pyrimidin-4(3H)-ones with mesyl, tosyl, and p-cyanobenzenesulfonyl chloride was studied. A hydrogen substituent at 2-position directed the sulfonyl group to the N-3 position, while alkylsulfanyl or amino substituents led to sulfonylation of the carbonyl oxygen. The latter effect was attributed to steric influence and the positive mesomeric effect of the 2-substituent. An access to N-sulfonylated 2-substituted regioisomers was established. An unexpected 1,3-sulfonyl migration was observed and further analyzed. This process occurred as an intramolecular N- to O-shift as verified by kinetic and crossover experiments.
authors: Pharmaceutical Institute, Pharmaceutical Chemistry I, University of Bonn , An der Immenburg 4, D-53121 Bonn, Germany.
authors: Matthias D
authors: MD
authors: Mertens
authors: Markus
authors: M
authors: Pietsch
authors: Gregor
authors: G
authors: Schnakenburg
authors: Michael
authors: M
authors: Gütschow
mesh_terms: D015394:Molecular Structure; D011744:Pyrimidinones / Q000737:chemistry*; D052999:Quinazolinones / Q000737:chemistry*; D013237:Stereoisomerism; D013438:Sulfhydryl Compounds / Q000138:chemical synthesis* / Q000737:chemistry
chemical_list: D011744:Pyrimidinones; D052999:Quinazolinones; D013438:Sulfhydryl Compounds; C586597:tetrahydrobenzothieno(2,3-d)pyrimidin-4(3H)-one