| abstract |
This invention relates to improved synthesis of benzothiazine dioxide, which are potent and selective endothelin antagonists, which is why they are particularly useful in the treatment of elevated levels of endothelin, acute and chronic renal failure, pulmonary hypertension, cancer, injury of gastric mucosa, hemorrhagic attack, ischemic bowel disease and diabetes. Process for the preparation of compounds of the general formula Where R1 is H, alkyl, alkoxy, R2 is h, alkoxy, R3 is alkyl or alkoxy; R2 and R3 can form a threadndioxy ring R4 is H, alkyl; R5 is H alkyl, alkoxy, halogen (in position 2, o3, o4, o5), 3,4 methylenedioxo. R6 is CF3, halogen, alkyl, benzyl, phenyl, hydroxy, or pyrrole. Example: 4- (3,5-dimethoxy-phenyl) -2- (trifluoromethyl-phenyl) -1,1-dioxo-1,2-dihydro-lambda a la 6-benzo (e) (1,2) thiazino- 3-carboxylic. |