Derivatives of 1,2,3,3a,8,8a-hexadydropyrrolo (2,3-b) indole

Abstract From the Canadian patent

The invention provides novel compounds which display useful analgesic properties. The compounds are 1,2,3,3a,8,8a-hexahydropyrrolo 2,3-b indoles of formula I, and pharmaceutically acceptable salts thereof wherein R1 is selected from the, group consisting of hydrogen hydroxy, C1 - C12 alkoxy and C2 - C12 alkenyloxy; R2 is selected from the group consisting of hydrogen and C1 - C12 alkyl; R3 and R4 are the same or different and are selected from the group consisting of hydrogen, C1 - C12 alkyl and C2 - C12 alkenyl provided that when R1 is selected, from the group consisting of hydrogen hydroxy, methoxy and ethoxy, and R2 is methyl, at least one of R3 and R4 is other than hydrogen or methyl.