title: Synthesis of 3-amino-1,2,4-benzothiadi- azine 1,1-dioxides via a tandem aza-Wittig/heterocumulene annulation.
abstract: [reaction: see text] Reaction of o-azidobenzenesulfonamides with polymer-supported triphenylphosphine affords the corresponding iminophosphoranes. Subsequent reaction with isocyanates gives 3-amino-1,2,4-benzothiadiazine 1,1-dioxides in high yields and purities. The reaction has been successfully applied to the synthesis of derivatives with various substituents at the 2- and 3-positions and in the benzenoid ring.
authors.affiliation: Department of Medicinal Chemistry, Millennium Pharmaceuticals, 35 Landsdowne Street, Cambridge, Massachusetts 02139, USA. chris.blackburn@mpi.com
authors.forename: Christopher
authors.initials: C
authors.lastname: Blackburn
authors.forename: Abe
authors.initials: A
authors.lastname: Achab
authors.forename: Amy
authors.initials: A
authors.lastname: Elder
authors.forename: Shomir
authors.initials: S
authors.lastname: Ghosh
authors.forename: Jianping
authors.initials: J
authors.lastname: Guo
authors.forename: Geraldine
authors.initials: G
authors.lastname: Harriman
authors.forename: Matthew
authors.initials: M
authors.lastname: Jones
mesh_terms: D001386:Azides / Q000737:chemistry*; D003500:Cyclization; D017953:Isocyanates / Q000737:chemistry*; D015394:Molecular Structure; D009943:Organophosphorus Compounds / Q000737:chemistry*; D013237:Stereoisomerism; D013449:Sulfonamides / Q000737:chemistry*; D000077704:Tirapazamine; D014227:Triazines / Q000138:chemical synthesis* / Q000737:chemistry; D000096926:Benzenesulfonamides
chemical_list: D001386:Azides; D017953:Isocyanates; D009943:Organophosphorus Compounds; D013449:Sulfonamides; D000077704:Tirapazamine; D014227:Triazines; C511509:o-azidobenzenesulfonamide; D000096926:Benzenesulfonamides; C061896:triphenylphosphine