| abstract |
Compounds having the formula X, IV or VIa <IMAGE> or a pharmaceutically acceptable salt of a compound of formula VIa, wherein the dotted line represents optional unsaturation, R1 is hydrogen or alkyl of 1 to 6 carbon atoms; R2 is hydrogen or alkyl of 1 to 6 carbon atoms; R4 is hydrogen or alkyl of 1 to 6 carbon atoms; R7 is hydrogen or alkyl of 1 to 6 carbon atoms; n is 0, 1, 2, 3 or 4; and R5 and R6 in formulae X and VIa are independently, hydrogen, hydroxy, alkyl of 1 to 6 carbon atoms, alkoxy of to 6 carbon atoms, aralkoxy of 7 to 9 carbon atoms, alkanoyloxy of 2 to 7 carbon atoms, alkylmercapto of 1 to 6 carbon atoms, N-protected amino, halo, trifluoromethyl or, when taken together, methylenedioxy and R5 and R6 in formula IV are ortho or para substituents independently selected from hydrogen, hydroxyl, alkyl of 1 to 6 carbon atoms, alkoxy of 1 to 6 carbon atoms, aralkoxy of 7 to 9 carbon atoms, alkanoyloxy of 2 to 7 carbon atoms, alkylmercapto of 1 to 6 carbon atoms, halo and trifluoromethyl are used as intermediates. |