Compounds of the class of 1-[2- and 3-[4-(10,11-dihydro-5H-dibenzo[a,d]cyclohepten-10-yl)-1-piperazinyl]-alkyl ]-3-alkyl-2-imidazolidinone which can be substituted in 8-position by chloro, methyl or methoxy, and the pharmaceutically acceptable acid addition salts thereof, have a depressant effect on the central nervous system; pharmaceutical compositions comprising these compounds and a method of producing a depressant effect on the central nervous system of warm-blooded animals, are provided; an illustrative embodiment is 1-[2-[ 4-(8-methyl-10,11-dihydro-5H-dibenzo[a,d]cyclohepten-10-yl)-1-piperazinyl] -ethyl]-3-methyl-2-imidazolidinone-bis-maleate.
10-Substituted 5-cyanomethylene-10,11-dihydro-dibenzo[a,d]-cycloheptenes, their pharmaceutically tolerated addition salts with acids, processes for their preparation, and their use as drugs, especially as sedatives, hypnotics or tranquilizers.
![[4-(10,11-DIHYDRO-5H-DIBENZO[a,d]CYCLOHEPTEN-10-yL-1-P IPERAZINYL]-ALKYL]-3-ALKYL-2-IMIDAZOLIDINONES AS CNS DEPRESSANTS - US Patent 3720676 - Page 1](http://www.wikipatents.com/4-1011-dihydro-5h-dibenzoadcyclohepten-10-yl-1-p-iperazinyl-alkyl-3-alkyl-2-imidazolidinones-as-cns-depressants/T/US3720676-1.jpg "[4-(10,11-DIHYDRO-5H-DIBENZO[a,d]CYCLOHEPTEN-10-yL-1-P IPERAZINYL]-ALKYL]-3-ALKYL-2-IMIDAZOLIDINONES AS CNS DEPRESSANTS - US Patent 3720676 - Page 1")
![[4-(10,11-DIHYDRO-5H-DIBENZO[a,d]CYCLOHEPTEN-10-yL-1-P IPERAZINYL]-ALKYL]-3-ALKYL-2-IMIDAZOLIDINONES AS CNS DEPRESSANTS - US Patent 3720676 - Page 2](http://www.wikipatents.com/4-1011-dihydro-5h-dibenzoadcyclohepten-10-yl-1-p-iperazinyl-alkyl-3-alkyl-2-imidazolidinones-as-cns-depressants/T/US3720676-2.jpg "[4-(10,11-DIHYDRO-5H-DIBENZO[a,d]CYCLOHEPTEN-10-yL-1-P IPERAZINYL]-ALKYL]-3-ALKYL-2-IMIDAZOLIDINONES AS CNS DEPRESSANTS - US Patent 3720676 - Page 2")
![[4-(10,11-DIHYDRO-5H-DIBENZO[a,d]CYCLOHEPTEN-10-yL-1-P IPERAZINYL]-ALKYL]-3-ALKYL-2-IMIDAZOLIDINONES AS CNS DEPRESSANTS - US Patent 3720676 - Page 3](http://www.wikipatents.com/4-1011-dihydro-5h-dibenzoadcyclohepten-10-yl-1-p-iperazinyl-alkyl-3-alkyl-2-imidazolidinones-as-cns-depressants/T/US3720676-3.jpg "[4-(10,11-DIHYDRO-5H-DIBENZO[a,d]CYCLOHEPTEN-10-yL-1-P IPERAZINYL]-ALKYL]-3-ALKYL-2-IMIDAZOLIDINONES AS CNS DEPRESSANTS - US Patent 3720676 - Page 3")
![[4-(10,11-DIHYDRO-5H-DIBENZO[a,d]CYCLOHEPTEN-10-yL-1-P IPERAZINYL]-ALKYL]-3-ALKYL-2-IMIDAZOLIDINONES AS CNS DEPRESSANTS - US Patent 3720676 - Page 4](http://www.wikipatents.com/4-1011-dihydro-5h-dibenzoadcyclohepten-10-yl-1-p-iperazinyl-alkyl-3-alkyl-2-imidazolidinones-as-cns-depressants/T/US3720676-4.jpg "[4-(10,11-DIHYDRO-5H-DIBENZO[a,d]CYCLOHEPTEN-10-yL-1-P IPERAZINYL]-ALKYL]-3-ALKYL-2-IMIDAZOLIDINONES AS CNS DEPRESSANTS - US Patent 3720676 - Page 4")
![[4-(10,11-DIHYDRO-5H-DIBENZO[a,d]CYCLOHEPTEN-10-yL-1-P IPERAZINYL]-ALKYL]-3-ALKYL-2-IMIDAZOLIDINONES AS CNS DEPRESSANTS - US Patent 3720676 - Page 5](http://www.wikipatents.com/4-1011-dihydro-5h-dibenzoadcyclohepten-10-yl-1-p-iperazinyl-alkyl-3-alkyl-2-imidazolidinones-as-cns-depressants/T/US3720676-5.jpg "[4-(10,11-DIHYDRO-5H-DIBENZO[a,d]CYCLOHEPTEN-10-yL-1-P IPERAZINYL]-ALKYL]-3-ALKYL-2-IMIDAZOLIDINONES AS CNS DEPRESSANTS - US Patent 3720676 - Page 5")
![[4-(10,11-DIHYDRO-5H-DIBENZO[a,d]CYCLOHEPTEN-10-yL-1-P IPERAZINYL]-ALKYL]-3-ALKYL-2-IMIDAZOLIDINONES AS CNS DEPRESSANTS - US Patent 3720676 - Page 6](http://www.wikipatents.com/4-1011-dihydro-5h-dibenzoadcyclohepten-10-yl-1-p-iperazinyl-alkyl-3-alkyl-2-imidazolidinones-as-cns-depressants/T/US3720676-6.jpg "[4-(10,11-DIHYDRO-5H-DIBENZO[a,d]CYCLOHEPTEN-10-yL-1-P IPERAZINYL]-ALKYL]-3-ALKYL-2-IMIDAZOLIDINONES AS CNS DEPRESSANTS - US Patent 3720676 - Page 6")
