Diisopropyl Ether → 6-(4-Oxo-4H-1,3-benzothiazin-2-yl)-2-pyridinecarboxylic acid
Reaktionsgleichung
[O:1]=[C:2]1[C:7]2[CH:8]=[CH:9][CH:10]=[CH:11][C:6]=2[S:5][C:4]([C:12]2[N:17]=[C:16]([C:18]([O:20]C(C)(C)C)=[O:19])[CH:15]=[CH:14][CH:13]=2)=[N:3]1.C(OC(C)C)(C)C>FC(F)(F)C(O)=O>[O:1]=[C:2]1[C:7]2[CH:8]=[CH:9][CH:10]=[CH:11][C:6]=2[S:5][C:4]([C:12]2[N:17]=[C:16]([C:18]([OH:20])=[O:19])[CH:15]=[CH:14][CH:13]=2)=[N:3]1Komponenten
4
Versuchsvorschrift
A mixture of tert-butyl 6-(4-oxo-4H-1,3-benzothiazin-2-yl)-2-pyridinecarboxylate (400 mg, 1.1 mmol) and trifluoroacetic acid (10 ml) was stirred under ice cooling condition for 3 hrs. The reaction mixture was combined with diisopropylether to precipitate crystals, which were collected by filtration and recrystallized from methanol-diisopropylether to give the titled compound (245 mg, 73%).