Abstract:
Compounds of the formula ##SPC1## 
     And pharmaceutically acceptable salts alkylthio, wherein R 1  is hydrogen, halogen, alkyl, alkoxy, alkythio, benzyl, phenylethyl, phenyl, phenylthio, or phenyl mono-substituted with a halogen, an alkyl group, an alkoxy group or a trifluoromethyl group; R 2  is hydrogen, Halogen, alkyl, alkoxy, alkylthio, alkylsulfonyl, phenyl phenyloxy, sulfamoyl, dialkylamidosulfonyl, trifluoromethyl or phenyl or phenyloxy mono-substituted with a halogen, an alkyl group, an alkoxy group or a trifluoromethyl group; R 3  is hydrogen, alkyl or or hydroxyalkyl; and n is 2, 3 or 4 are useful as central nervous system depressants.

Description:
SUMMARY OF THE INVENTION 
     Compounds having the formula ##SPC2## 
     And pharmaceutically acceptable salts thereof, are useful central nervous system depressants. In formula I, and throughout the specification, the symbols are as defined below: 
     R 1  is hydrogen, halogen, alkyl, alkoxy, alkylthio, benzyl, phenylethyl, phenyl, phenylthio, or phenyl mono-substituted with alkyl, alkoxy, or trifluoromethyl; 
     R 2  is hydrogen, halogen, alkyl, alkoxy, alkylthio, alkylsulfonyl, phenyl, phenyloxy, sulfamoyl, dialkylamidosulfonyl, trifluoromethyl, or phenyl or phenyloxy mono-substituted with halogen, alkyl, alkoxy, or trifluoromethyl; 
     R 3  is hydrogen, alkyl or hydroxyalkyl; 
     R 4  is alkyl or hydroxyalkyl; and 
     n is 2, 3 or 4. 
     The term &#34;alkyl&#34; as used throughout the specification refers to straight or branched chain alkyl groups having 1 to 4 carbon atoms, e.g., methyl, ethyl, propyl, isopropyl, butyl, t-butyl, etc. Those alkyl groups having 1 to 3 carbon atoms are preferred. 
     The term &#34;alkoxy&#34; as used throughout the specification refers to groups having the formula Y--O-- wherein Y is alkyl as defined above. Alkoxy groups having 1 to 3 carbon atoms are preferred. 
     The term &#34;halogen&#34; as used throughout the specification refers to fluorine, chlorine, bromine and iodine. Chlorine and bromine are the preferred halogens. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The compounds of formula I are prepared from 11,12-dihydropyrido[2,1-b][1,3]benzodiazepines having the formula: ##SPC3## 
     These compounds are known; see Yale et al., U.S. Pat. No. 3,825,549 issued July 23, 1974, the disclosure of which is incorporated herein by reference. 
     The compounds of formula II can be reduced, using procedures well known in the art. The compounds undergo hydrogenolysis to yield compounds having the formula: ##SPC4## 
     The reaction can be carried out in an organic solvent, preferably a lower alkanol such as methanol, using a catalyst such as platinum oxide or Raney nickel and gaseous hydrogen. The intermediates of formula III, are novel, and as such they constitute a part of this invention. 
     The alkylation of a compound of formula III can be carried out by either of two alternative processes. Reaction of a compound of formula III with an appropriate base, e.g., sodium hydride or thallous ethoxide, yields a salt having the structure: ##SPC5## 
     The reaction can be run in an inert polar solvent, e.g., dimethylsulfoxide or dimethylformamide. Reaction conditions are not critical, and the reaction can be run at room temperature for a period of from 1 minute to several hours. The salt of formula IV is subsequently reacted with a compound having the formula: 
     
         R.sub.3 R.sub.4 --N--(CH.sub.2).sub.n --X                  V 
    
     wherein X is chlorine, bromine, alkylsulfonate (e.g., methanesulfonate) or arylsulfonate (e.g., toluenesulfonate) to obtain a compound of formula I. 
     Alternatively, the alkylation of a compound of formula III can be accomplished by first reacting the piperidine derivative with a compound having the formula 
     
         Cl--(CH.sub.2).sub.n --Br                                  VI 
    
     to yield a compound having the structure ##SPC6## 
     The reaction can be run in an organic solvent, preferably tetrahydrofuran or methyl ethyl ketone in the presence of a base such as sodium hydride or sodium hydroxide. Reaction conditions are not critical, but the reaction will preferably be run under reflux conditions for about 6 hours to 24 hours. The products of formula I can be formed by reacting a compound of formula VII with an amine having the structure 
     
         R.sub.3 R.sub.4 NH                                         VIII 
    
     the reaction can be run neat or in an organic solvent such as toluene. Reaction conditions are not critical and the reaction can be run at room temperature or at elevated temperatures. 
     The novel piperidine derivatives of formula I can be converted, using procedures well known in the art, into their pharmaceutically acceptable acid-addition salts. Illustrative of the salts contemplated for use in this invention are the hydrohalides (e.g., the hydrochloride and hydrobromide), sulfate, nitrate, tartrate, phosphate, maleate, fumarate, citrate, succinate, methanesulfonate, benzenesulfonate, toluenesulfonate, and the like. 
     The compounds of formula I, and the pharmaceutically acceptable acid-addition salts thereof, are useful in mammalian species such as rats, dogs, monkeys and others, as central nervous system depressants, and can be used as tranquilizers for the relief of anxiety and tension states in the same manner as chlordiazepoxide. For this purpose these compounds can be incorporated in a conventional dosage form such as tablet, capsule, injectable or the like, along with the necessary carrier material, excipient, lubricant, buffer or the like, for oral or parenteral administration in single or divided doses of about 1 to 100 mg/kg/day, preferably about 5 to 15 mg/kg, two to four times daily. 
     The following examples are specific embodiments of this invention. 
     EXAMPLE 1 
     1,1-Dimethyl-3-[2-[2-(1-piperidinyl)ethyl]phenyl]-1,3-propanediamine 
     A. 1-[2-(2-Aminophenyl)ethyl]piperidine 
     Platinum oxide catalyst (1.0 g) is added to a solution of 11,12-dihydropyrido[2,1-b][1,3]benzodiazepine (20.0 g) in methanol (550 ml). Hydrogen gas (about 50 psig) is added and hydrogen uptake is completed in about 1 and 2 hours. The catalyst is filtered off, and the filtrate is concentrated to yield 22.0 g of material that crystallizes spontaneously, melting point 36°-38° C. Recrystallization from 150 ml of pentane yields 16.0 g of the title compound, melting point 39°-41° C. 
     B. 1,1-Dimethyl-3-[2-[2-(1-piperidinyl)ethyl]phenyl]-1,3-propanediamine 
     To a solution of 1-[2-(2-aminophenyl)ethyl]piperidine (4.5 g) in anhydrous dimethylsulfoxide (18 ml) under a nitrogen blanket is added 1.2 g of 50% sodium hydride in mineral oil over a 30 minute period, with stirring, at 20° C. Following completion of the addition, the mixture is stirred for 2 hours at 20° C, and then treated with 3-(dimethylamino)propyl chloride (6.0 g) dropwise. Stirring is continued for 2 hours at 20° C and for an additional 2 hours at 40° C, followed by cooling and the addition of 2 ml of absolute ethanol. The reaction mixture is partitioned between 500 ml of water and 100 ml of ether. The aqueous phase is extracted successively with two 100 ml portions of ether, and the combined ether extracts are washed with water. The washed ether solution is reextracted with three 50 ml portions of cold 5% aqueous hydrochloric acid. The combined acid extracts are washed with ether, cooled, and treated with an excess of aqueous sodium hydroxide. The oil that separates is recovered by ether extraction to yield 5.40 g of the title compound, boiling point 200°-205° C (at 0.01 mm of Hg). 
     EXAMPLE 2 
     1,1-Dimethyl-3-[2-[2-(1-piperidinyl)ethyl]phenyl]-1,3-propanediamine, oxalate salt (1:1) 
     To a solution of 1,1-dimethyl-3-[2-[2-(1-piperidinyl)ethyl]phenyl]-1,3-propanediamine (2.1g) in 50 ml of 2-propanol is added 2.0g of oxalic acid in 25 ml of 2-propanol. The precipitate that forms is filtered, dissolved in 20 ml of methanol, and 40 ml of chloroform is added. The solution is then concentrated to 50 ml and the solution cooled; a fine crystalline mass is deposited. Recrystallization from methanol-chloroform (1:2) yields the title compound, melting point 101°-102° C. 
     EXAMPLE 3 
     1,1-Dimethyl-2-[2-[2-(1-piperidinyl)ethyl]phenyl]-1,2-ethanediamine 
     Following the procedure of Example 1, but utilizing in Part B 4.1g of 1-[2-(2-aminophenyl)ethyl]piperidine, 20 ml of dimethylsulfoxide and 2.0g of 50% sodium hydride in mineral oil, and substituting 4.3g of 2-(dimethylamino)ethyl chloride for 3-(dimethylamino)propyl chloride yields 5.25g of the title compound, boiling point 195°-197° C (at 0.2 mm of Hg). 
     EXAMPLE 4 
     1,1-Dimethyl-2-[2-[2-(1-piperidinyl)ethyl]phenyl]-1,2-ethanediamine, dihydrochloride 
     To a solution of 1,1-dimethyl-2-[2-[2-(1-piperidinyl)ethyl]phenyl]-1,2-ethanediamine (2.7g) prepared as described in Example 3 in dry ether (50 ml) is added, with stirring and cooling, 10 ml of N ethereal hydrogen chloride solution, dropwise; the title compound separates out. 
     EXAMPLES 5-46 
     Following the procedure of Example 1, but substituting the compound in column I below for 11,12-dihydropyrido[2,1-b][1,3]benzodiazepine and the compound listed in column II below for 3-(dimethylamino)propyl chloride, the compound listed in column III below is obtained. 
     
         __________________________________________________________________________Example  Column I        Column II   Column III__________________________________________________________________________5    3-chloro-11,12-dihydro-                3-(methylamino)propyl                            1-methyl-3-[4-chloro-2-[2-pyrido[2,1-b][1,3]benzo-                chloride    (1-piperidinyl)ethyl]phenyl]-diazepine                   1,3-propanediamine6    3-(methoxy)-11,12-dihydro-                2-(diisopropylamino)-                            1,1-diisopropyl-2-[4-(methoxy)-pyrido[2,1-b][1,3]benzo-                ethyl chloride                            2-[2-(1-piperidinyl)ethyl]-diazepine                   phenyl]-1,2-ethanediamine7    3-ethyl-11,12-dihydro-                2-(dimethylamino)-                            1,1-dimethyl-2-[4-ethyl-2-[2-pyrido[2,1-b][1,3]benzo-                ethyl chloride                            (1-piperidinyl)ethyl]phenyl]-diazepine                   1,2-ethanediamine8    4-(methylsulfonyl)-11,12-                2-(2-hydroxyethyl-                            1-(2-hydroxyethyl)-2-[3-(methyl-dihydropyrido[2,1-b][1,3]                amino)ethyl chloride                            sulfonyl)-2-[2-(1-piperidinyl)-benzodiazepine              ethyl]phenyl]-1,2-ethanediamine9    3-(phenyloxy)-11,12-di-                4-(methylamino)-                            1-methyl-4-[4-(phenyloxy)-2-hydropyrido[2,1-b][1,3]-                butyl chloride                            [2-(1-piperidinyl)ethyl]phenyl]-benzodiazepine              1,4-butanediamine10   2-(ethoxy)-11,12-di-                2-(butylamino)ethyl                            1-butyl-2-[5-(ethoxy)-2-[2-hydropyrido[2,1-b][1,3]-                chloride    (1-piperidinyl)ethyl]phenyl]-benzodiazepine              1,2-ethanediamine11   2-fluoro-11,12-dihydro-                2-[di-(2-hydroxy-                            1,1-di-(5-hydroxyethyl)-2-pyrido[2,1-b][1,3]benzo-                ethyl)amino]ethyl                            [4-fluoro-2-[2-(1-piperidinyl)-diazepine       chloride    ethyl]phenyl]-1,2-ethanediamine12   2-(diethylamidosulfonyl)-                3-(dimethylamino)-                            1,1-dimethyl-3-[5-(diethyl-11,12-dihydropyrido[2,1-b]-                propyl chloride                            amidosulfonyl)-2-[2-(1-piper-[1,3]benzodiazepine         idinyl)ethyl]phenyl-1,3-propane-                            diamine13   1-fluoro-11,12-dihydro-                4-(ethylamino)-                            1-ethyl-4-[6-fluoro-2-[2-(1-pyrido[2,1-b][1,3]benzo-                butyl chloride                            piperidinyl)ethyl]phenyl-1,4-diazepine                   butanediamine14   3-sulfamoyl-11,12-dihydro-                2-(propylamino)-                            1-propyl-2-[4-sulfamoyl-2-[2-pyrido[2,1-b][1,3]benzodia-                ethyl chloride                            (1-piperidinyl)ethyl]phenyl]-zepine                      1,2-ethanediamine15   3-(trifluoromethyl)-11,12-                2-(t-butylamino)-                            1-t-butyl-2-[4-(trifluoromethyl)-dihydropyrido[2,1-b][1,3]-                ethyl chloride                            2-[2-(1-piperidinyl)ethyl]phenyl]-benzodiazepine              1,2-ethanediamine16   2-chloro-11,12-dihydro-                3-(dimethylamino)-                            1,1-dimethyl-3-[5-chloro-2-pyrido[2,1-b][1,3]benzo-                propyl chloride                            [2-(1-piperidinyl)ethyl]phenyl]-diazepine                   1,3-propanediamine17   3-(methylthio)-11,12-di-                2-(dimethylamino)-                            1,1-dimethyl-2-[4-(methylthio)-hydropyrido[2,1-b][1,3]-                ethyl chloride                            2-[2-(1-piperidinyl)ethyl]phenyl]-benzodiazepine              1,2-ethanediamine18   8-chloro-3-(p-tolyl)-11,12-                3-(dimethylamino)-                            1,1-dimethyl-3-[4-(p-tolyl)-2-dihydropyrido[2,1-b][1,3]-                propyl chloride                            [2-(3-chloro-1-piperidinyl)ethyl]-benzodiazepine              phenyl]-1,3-propanediamine19   8-bromo-4-[m-(tri-                4-(dimethylamino)-                            1,1-dimethyl-4-[3-[m-(trifluoro-fluoromethyl)phenyl]-                butyl chloride                            methyl)phenyl]-2-[2-(3-bromo-11,12-dihydropyrido-        1-piperidinyl)ethyl]phenyl]-1,4-[2,1-b][1,3]benzodia-       butanediaminezepine20   8-ethyl-4-[p-(methoxy)-                2-(diethylamino)-                            1,1-diethyl-2-[3-[p-(methoxy)-phenyl]-11,12-dihydro-                ethyl chloride                            phenyl]-2-[2-(3-ethyl-1-piper-pyrido[2,1-b][1,3]benzo-    idinyl)ethyl]phenyl]-1,2-ethane-diazepine                   diamine21   2-methyl-11,12-dihydro-                3-[(3-hydroxy-                            1-(3-hydroxypropyl)-2-[5-methyl-pyrido[2,1-b][1,3]benzo-                propyl)amino]propyl                            2-[2-(1-piperidinyl)ethyl]phenyl]-diazepine       chloride    1,3-propanediamine22   3-(dipropylamidosul-                2-(methylamino)-                            1-methyl-2-[4-(dipropylamido-fonyl)-11,12-dihydro-                ethyl chloride                            sulfonyl)-2-[2-(1-piperidinyl)-pyrido[2,1-b][1,3]benzo-    ethyl]phenyl]-1,2-ethanediaminediazepine23   1-(o-chlorophenyl)-11,12-                3-(dimethylamino)-                            1,1-dimethyl-3-[6-(o-chloro-dihydropyrido[2,1-b][1,3]-                propyl chloride                            phenyl)-2-[2-(1-piperidinyl)-benzodiazepine              ethyl]phenyl]-1,3-propanediamine24   8-chloro-11,12-dihydro-                4-(dimethylamino)-                            1,1-dimethyl-4-[2-[2-(3-chloro-pyrido[2,1-b][1,3]benzo-                butyl chloride                            1-piperidinyl)ethyl]phenyl]-diazepine                   1,4-butanediamine25   6-bromo-11,12-dihydro-                2-(ethylamino)-                            1-ethyl-2-[2-[2-(3-bromo-1-pyrido[2,1-b][1,3]benzo-                ethyl chloride                            piperidinyl)ethyl]phenyl]-1,2-diazepine                   ethanediamine26   8-bromo-11,12-dihydro-                2-(diethylamino)-                            1,1-diethyl-2-[2-[2-(3-bromo-pyrido[2,1-b][1,3]benzo-                ethyl chloride                            1-piperidinyl)ethyl]phenyl]-1,2-diazepine                   ethanediamine27   6-(ethoxy)-11,12-dihydro-                2-(propylamino)-                            1-propyl-2-[2-[2-[3-(ethoxy)-pyrido[2,1-b][1,3]benzo-                ethyl chloride                            1-piperidinyl]ethyl]phenyl]-1,2-diazepine                   ethanediamine28   7-(ethoxy)-11,12-dihydro-                2-(diisopropyl-                            1,1-diisopropyl-2-[2-[2-[4-(ethoxy)-pyrido[2,1-b][1,3]benzo-                amino)ethyl chloride                            1-piperidinyl]ethyl]phenyl]-1,2-diazepine                   ethanediamine29   8-ethyl-11,12-dihydro-                3-(methylamino)-                            1-methyl-3-[2-[2-(3-ethyl-1-pyrido[2,1-b][1,3]benzo-                propyl chloride                            piperidinyl)ethyl]phenyl]-1,3-diazepine                   propanediamine30   8-(ethoxy)-11,12-dihydro-                3-(dimethylamino)-                            1,1-dimethyl-3-[2-[2-[3-(ethoxy)-pyrido[2,1-b][1,3] benzo-                propyl chloride                            1-piperidinyl]ethyl]phenyl]-1,3-diazepine                   propanediamine31   6-ethyl-11,12-dihydro-                3-(ethylamino)-                            1-ethyl-3-[2-[2-(3-ethyl-1-piper-pyrido[2,1-b][1,3]benzo-                propyl chloride                            idinyl)ethyl]phenyl]-1,3-propane-diazepine                   diamine32   6-butyl-11,12-dihydro-                3-(diethylamino)-                            1,1-diethyl-3-[2-[2-(3-butyl-1-pyrido[2,1-b][1,3]benzo-                propyl chloride                            piperidinyl)ethyl]phenyl]-1,3-diazepine                   propanediamine33   9-phenyl-11,12-dihydro-                3-(propylamino)-                            1-propyl-3-[2-[2-(2-phenyl-1-pyrido[2,1-b][1,3]benzo-                propyl chloride                            piperidinyl)ethyl]phenyl]-1,3-diazepine                   propanediamine34   8-chloro-11,12-dihydro-                3-(dipropylamino)-                            1,1-dipropyl-3-[2-[2-(3-chloro-pyrido[2,1-b][1,3]benzo-                propyl chloride                            1-piperidinyl)ethyl]phenyl]-1,3-diazepine                   propanediamine35   6-benzyl-1-(trifluoro-                3-(butylamino)-                            1-butyl-3-[2-[2-(3-benzyl-1-methyl)-11,12-dihydro-                propyl chloride                            piperidinyl)ethyl]phenyl]-1,3-pyrido[2,1-b][1,3]benzo-    propanediaminediazepine36   6-[m-(ethoxy)phenyl]-3-                3-(dibutylamino)-                            1,1-dibutyl-3-[4-fluoro-2-[2-fluoro-11,12-dihydro-                propyl chloride                            [3-[m-(ethoxy)phenyl]-1-piper-pyrido[2,1-b][1,3]benzo-    idinyl]ethyl]phenyl]-1,3-propane-diazepine                   diamine37   1-(trifluoromethyl)-8-                4-(methylamino)-                            1-methyl-4-[6-(trifluoromethyl)-[o-(trifluoromethyl)-                butyl chloride                            2-[2-[3-[o-(trifluoromethyl)phenyl]-phenyl]-11,12-dihydro-      1-piperidinyl]ethyl]phenyl]-1,4-pyrido[2,1-b][1,3]benzo-    butanediaminediazepine38   3-chloro-8-(o-tolyl)-                4-(dimethylamino)-                            1,1-dimethyl-4-[4-chloro-2-11,12-dihydropyrido-                butyl chloride                            [2-[3-[o-tolyl)-1-piperidinyl]-[2,1-b] [1,3]benzodia-      ethyl]phenyl]-1,4-butanediaminezepine39   8-(phenylthio)-11,12-di-                4-(ethylamino)-                            1-ethyl-4-[2-[2-[3-(phenylthio)-hydropyrido[2,1-b][1,3]-                butyl chloride                            1-piperidinyl]ethyl]phenyl]-1,4-benzodiazepine              butanediamine40   6-(2-phenylethyl)-11,12-                4-(diethylamino)-                            1,1-diethyl-4-[2-[2-[3-(2-phenyl-dihydropyrido[2,1-b]-                butyl chloride                            ethyl)-1-piperidinyl]ethyl]phenyl]-[1,3]benzodiazepine         1,4-butanediamine41   6-(o-bromophenyl)-11,12-                4-(dipropylamino)-                            1,1-dipropyl-4-[2-[2-[3-(o-dihydropyrido[2,1-b]-                butyl chloride                            bromophenyl)-1-piperidinyl]-[1,3]benzodiazepine         ethyl]phenyl]-1,4-butanediamine42   3-phenyl-11,12-dihydro-                2-(dimethylamino)-                            1,1-dimethyl-2-[4-phenyl-2-pyrido[2,1-b][1,3]benzo-                ethyl chloride                            [2-(1-piperidinyl)ethyl]phenyl]-diazepine                   1,2-ethanediamine43   3-(o-tolyloxy)-11,12-di-                3-(dimethylamino)-                            1,1-dimethyl-3-[4-(o-tolyloxy)-hydropyrido[2,1-b][1,3]-                propyl chloride                            2-[2-(1-piperidinyl)ethyl]phenyl]-benzodiazepine              1,3-propanediamine44   2-[m-(ethoxy)phenoxy]-                4-(dimethylamino)-                            1,1-dimethyl-4-[5-[m-(ethoxy)-11,12-dihydropyrido-                butyl chloride                            phenoxy]-2-[2-(1-piperidinyl)-[2,1-b][1,3]-benzodia-      ethyl]phenyl]-1,4-butanediaminezepine45   3-[o-(trifluoromethyl)-                2-(ethylamino)-                            1-ethyl-2-[4-[o-(trifluoromethyl)-phenoxy]-11,12-dihydro-                ethyl chloride                            phenoxy]-2-[2-(1-piperidinyl)-pyrido[2,1-b][1,3]benzo-    ethyl]phenyl]-1,2-ethanediaminediazepine46   2-(o-bromophenoxy)-11,12-                2-(dimethylamino)-                            1,1-dimethyl-2-[5-(o-bromophenoxy)-dihydropyrido[2,1-b][1,3]-                ethyl chloride                            2-[2-(1-piperidinyl)ethyl]phenyl]-benzodiazepine              1,2-ethanediamine__________________________________________________________________________