2067181 9104973 PCTABS00003 Indole derivatives of formula (I) wherein R1, R2, R3 and R4 may be hydrogen or lower alkyl optionally substituted by halogen; X represents oxygen or sulfur; A1 represents a straight or branched alkylene chain containing from 2 to 4 carbon atoms; R5 is hydrogen or a straight or branched alkyl group; A2 is a straight or branched, saturated or unsaturated hydrocarbon chain containing from 2 to 6 carbon atoms; and R6 is selected from a group consisting of various structures, have been found to exhibit central nervous system activities.
INDOLE DERIVATIVES, THEIR PREPARATION AND USE