title: Direct formation of ring-fused 1,3-thiazine-2,4-dithiones from aromatic o-amino carboxylic acids: observation of a carbon disulfide mediated thionation.
abstract: A facile synthesis of 2H-3,1-benzothiazine-2,4(1H)-dithiones (trithioisatoic anhydrides) or 2H-naphtho[2,3-d][1,3]thiazine-2,4(1H)-dithione solely from anthranilic acids or 3-amino-2-naphthoic acid and carbon disulfide, performed at room temperature in 1,4-dioxane in the presence of Et(3)N, is reported. Corresponding 2-alkylsulfanyl derivatives were obtained in one-pot reactions under the same conditions after addition of alkyl halides. The mechanism of the thiazine cyclization was investigated using (13)C-labeled carbon disulfide to reveal that carbon disulfide was incorporated into the heterocycle and additionally acted as a thionation reagent.
authors.affiliation: Pharmaceutical Institute, Pharmaceutical Chemistry I, University of Bonn, An der Immenburg 4, D-53121 Bonn, Germany.
authors.forename: Philipp A
authors.initials: PA
authors.lastname: Ottersbach
authors.forename: Paul W
authors.initials: PW
authors.lastname: Elsinghorst
authors.forename: Hans-Georg
authors.initials: HG
authors.lastname: Häcker
authors.forename: Michael
authors.initials: M
authors.lastname: Gütschow
mesh_terms: D002246:Carbon Disulfide / Q000737:chemistry*; D002264:Carboxylic Acids / Q000737:chemistry*; D018360:Crystallography, X-Ray; D009682:Magnetic Resonance Spectroscopy; D008968:Molecular Conformation; D015394:Molecular Structure; D013237:Stereoisomerism; D013843:Thiazines / Q000138:chemical synthesis* / Q000737:chemistry; D013871:Thiones / Q000138:chemical synthesis* / Q000737:chemistry
chemical_list: D002264:Carboxylic Acids; D013843:Thiazines; D013871:Thiones; D002246:Carbon Disulfide