CA1152998A

CA1152998A - Isoquinoline derivatives and preparation thereof

Info

Publication number: CA1152998A
Application number: CA000356370A
Authority: CA
Inventors: Gilbert Lavielle; Andre Buzas
Original assignee: Individual
Current assignee: Individual
Priority date: 1979-07-19
Filing date: 1980-07-17
Publication date: 1983-08-30
Also published as: MX5962E; DK310180A; NO155883C; FR2461702B1; DE3027338C2; FI77027C; IN154316B; DE3027338A1; FR2461702A1; DK152124C; ES8106500A1; IE801498L; CH644848A5; DK152124B; NL8004053A; AR228953A1; EG14616A; IT1237319B; NZ194280A; AU538065B2

Abstract

A B S T R A C T

The present invention relates to new 1-[1-(3,4-dimethoxy-phenyl) -3-amino-propyl]-6,7-dimethoxy-isoquinolines having the general formula I :

I

in which R1 represents a hydrogen atom or a methyl group ;
and R2 represents an alkyl group having from 1 to 5 carbon atoms or a cycloalkyl group having from 5 to 7 carbon atoms, the alkyl or cycloalkyl group optionally being substituted by a hydroxy, phenyl or phenoxy group and the cycloalkyl group optionally being substituted by an alkyl group having from 1 to 5 carbon atoms, therapeutically acceptable salts thereof and a process preparation of the same. These compounds are useful in the cardiac and vascular fields.

Description

liSZ~

NEW ISOQU.INOLINE.DERIVAT.IVES.AND.PREPARATION THEREOF

The invention relates to new isoquinoline derivatives and to a process for their preparation.
The invention provides derivatives of 1~ (3,4-dimethoxy-phenyl)-3-amino-propyl~-6,7-dimethoxy-isoquinoline having the general formula I :

CH3 ~ R

OCH3 -.

in which Rl represents a hydrogen atom or a methyl group ; and R2 represents an alkyl group having from 1 to 5 carbon atoms or a cycloalkyl group having from 5 to 7 carbon atoms, the alkyl or cycloalkyl group optionally being substituted by a hydroxy, phenyl or phenoxy group and the cycloalkyl group optionally being substituted by an alkyl group having from 1 to 5 carbon atoms, and therapeutically acceptable salts thereof.
The compounds according to the invention are of interest for their therapeutic properties, particularly in the cardiac and vascular fields.
: The invention further provides a process for the preparation of 1-~1-( 3,4-dimethoxy-phenyl)- 3 -amino-propyl]-6,7-dimethoxy-isoquinoline derivatives of the general formula I as above defined : the process comprising co~densing, in a polar solvent, between 0 and 25C, 1-~1- (3 ,4-dimethoxy-phenyl)-3-oxo-propy~
-6,7-dimethoxy-isoquinoline, which has the formula II, ~' ': ' 5Z9~8 CH3O ~

with a compound of the general formula HNRlR2 wherein Rl and R2 are as above defined, and reducing the resultant compound by any of the convention techniques, e.g. hydrogenation or, preferably, of sodium borohydride.
The solvent generally used is an alcohol, preferably ethanol. Although the process according to the invention is applicable when both Rl and R2 represent hydrogen atoms and when neither Rl nor R2 represents a hydrogen atom, it offers the best yields in the preparation of secondary amines (i.e.
when Rl represents a hydrogen atom) and of the tertiary amines where Rl stands for methyl group. The tertiary derivatives can also be obtained starting from the secondary derivatives by well known nitrogen substitution techniques such as iodoalkylation or reductive formylation.
The starting material 1~ (3,4-dimethoxy-phenyl)-3-oxo-propy~ -6,7-dimethbxy-isoquinoline II, may be prepared by the methods described in detail with reference to the examples A, B and C below. Regarding the analytical data given in the examples A, B and C, and in the examples 1 to 10 thereafter, which latter illustrate the invention, the thin layer chromatography (TLC) data Was obtained using Merck F 254 plates ; the NMR spectra were recorded on Perkin-Elmer R 24 (60 MHz) apparatus ; and the I.R. spectra were recorded on Perkin-Elmer 257 apparatus.

. . .
:. , ~ 5~998 Exa~le A
_rmation of the c-arbanion of '1'-'[1-(3,4-dimethoxy-phenyl)-methy~
-6,7-dimethoxy-iso~uinoline a) Liquid ammonia/soda~ide ~ethod Into a 1 litre three-necked flask provided with stirring means and dry ice refrigeration means are successively introduced 300 ml of liquid ammonia, 0.1 g of ferric chloride acting as catalyst and 0.8 g (0.03 mole) of sodium (cf. Org Synthese Coll., Vol. 5, p. 523). The reaction mixture is stirred for 1 1/2 hours and there is then added, in small portions, 10 g (0.0295 mole) of papaverine. To complete the formation of the carbanion, the mixture is stirred for 2 hours. A red solution is obtained, for use as such in synthesis reactions, for instance those described in the examples hereinbelow.
b) ~utyl lithium/hexamethylphos-photri'amide method Into a 1 litre reactor~ fitted with heating, cooling and stirring means, are poured 10 g (0.0295 mole) of papaverine and 100 ml of hexamethylphbsphotriamide. Keeping the temperature at approximately 5C, there is progressively added 18.5 ml (0.03 mole) of commercial butyl lithium in solution in hexane. After the addition is complete, stirring is continued for 1 ho~r at ambient temperature.
c) -Sodamide/hexam-ethylphosphotriamide method Into the same apparatus as in method (b) above are poured 10 g (0.0295 mole) of papaverine and 30 ml of hexamethylphospho-triamide. 1.2 g (0.03 mole) of sodamide are added gently under stirring ; the mixture becomes red but there is no evolution of gases. The mixture is heated to 70-75C, resulting in evolution of ammonia ; sti~ring is continued for 3 hours until the gaseous evolution ends. The reaction mixture is cooled for use as such in synthesis reactions.
d) ~ithiu~ diiso'pro-pyl'ami'de/t'etrahydrofur'an method In the same apparatus as in method (a) above, cooled by an ethanol/dry ice bath, are poured 400 ml of dry tetrahydrofuran.
~ithium diisopropylamide is prepared in situ by adding dropwise at -30C, 18.5 ml of butyl-lithium (0.03 mole) dissolved in hexane'; 4.2 ml (0.03 mole) of diisopropylamine are added and the mixture is stirred for 15 mn at 10C ; after cooling at -40C, 10 g (0.0295 mole) of papaverine (powder) are added and the mixture is stirred for 4 hours at -40C.

:~SZ998 e) Potassium amide/dimethyl formamide method In the same apparatus as in example (b) above are poured 10 g (0.0295 mole) of papaverine and 35 ml of dimethyl formamide. 1.7 g (0.03 mole) of potassium amide are slowly added, under stirring. After the end of the addition, stirring is maintained while the reacting mixture is warmed at 70C for 3 hours and a half.
The reaction mixture is used as such, after cooling, for further syntheses.
For characterization'and identification of the carbanion, the oxidation reaction leading to l-(3,4-dimethoxy-benzoyl)-6,7-dimethoxy-isoquinoline (papaveraldine) is used. Into the solution of the carbanion prepared according to A(a) is bubbled for 2 1/2 hours a current of dry oxygen ; then 200 ml of dry toluene is poured-in and the ammonia is allowed to evaporate off. The solution is treated at ambient temperature with 200 ml of water and dried. m.p. 208C (Literature : 209-210C).

Example' B
Formation of the acetal intermediate : l- G - (3,4-dimethoxy-phenyl)-3,3-diethoxy-~propyl3-6,7-dimethoxy-i's'oquinoline To a solution containing 0.016 mole of the carbanion obtained by one of the methods described in example A there is slowly added 5.3g(0.025 mole) of 2,2-diethoxy-ethyl bromide.
After stirring for 1 hour, 200 ml of dry toluene is added and the ammonia is allowed to evaporate off. At ambient temperature, 200 ml of water is added and the whole'is filtered over celite.
The toluene'solution is then decanted, washed, dried over anhydrous sodium sulfate and concentrated. The oil obtained is directly hydrolyzed which'gives 9.6 g of product. Yield 97 %.
NMR (CC14) ~ppm : 8.20 (d, lH,''CH-N=) ; 7 (m, 6H, aromatic protons) ;
4.25 (t, lH,''CH-CH2);3.75 (m, 12H, OCH3);
3.3 (m, 4H, CH
~'OCH2

2.4 (m, 3H,' CH2'-CH ~ 2 5 ) ; 1 1 (2t 6H < 2 -3 :llS2998 Example C
Formation of the aldehyde : l=rl-(3,4-dimethoxy-'ph'e'nyl-)-3-oxo-~_opyl~-6,7-dimethoxy-isoquinoline 8.7 g (0.014 mole) of the compound prepared in example B
above are hydrolyzed for 2 hours at 50C in 200 ml of 2 %
hydrochloric acid solution. After alkalinisation at pH 12 with sodium carbonate, the mixture is extracted 3 times by 50 ml of dichloromethane. 7.25 g of an oil are obtained. Yield 95 %.
IR
vcm l : 2730, 171~ (CH=O) NMR (CDC13) ~ppm : 9.6 (s, lH, CH=O) ; 8.35 (d, lH, CH-N=) ; 7 (m, 6H, aromatic protons) ; 5.25 (t, lH, CH) ; 3.8 (m, 12H, OCH3) ;
.~0 2.9 (m, 2H~ CH2 C ~ H )' In the following examples 1 to 10, this compound is called "the aldehyde".

Exa~p'l'e 1 1-~l-(3,4-dimeth-oxy-phenyl)--3-amino-propy~ -6,7-dimethoxy-isoquinoline Rl = R2 = ~
This compound can be prepared starting from the aldehyde by three different routes.
a) Direct route ~y reductive amination 12 g of the'aldehyde are added to a cooled solution of 100 ml of ethanol saturated by ammonia and the mixture is put in a hydrogenation autoclave with 1 g of Raney nickel. Operation in under a pressure of 90 atmospheres. The solution is filtered and the solvent is evaporated off. The product is obtained in meaiocre yield because the hydrogenation under pressure also affects the isoquinoline nucleus. The following two methods lead, on the other hand, to excellent yields.
b)''Oxime route 7.6 g (0.02 mole) of the aldehyde, 60 ml of water and 60 ml of ethanol are refluxed for 1 1/2 hours in a 250 ml flask with 2 g of soda and 4.2 g of hydroxylamine hydrochloride. The solvents are then evaporated off and the residue is taken up in dichloro-methane and washed with water. 6.4 g (80 % yield) of 1-[1-(3,41-dimethoxy-phenyl)-3-hydroxyimino-propy~ -6,7-dimethoxy-isoquinoline is obtained.

llSZ~
NMR (CDC13) ~ppm : 8.3 (d, lH, CH-N=) ; 7.05 (m, 7H, aromatic protons and CH=N) ; 4.9 (m, lH, CH-CH2) ; 3 .8 (m, 13H, OCH3 and OH) ;

3.05 (m, 2H, CH2).
5 The reduction of this oxime by lithium aluminium hydride or its catalytic hydrogenation or its chemical reduction lead to the desired compound with good yields (85 % to 95 %).
NMR ( CDC 13) ~ppm : 8.45 (d, lH, CH-N=) ; 7.1 (m, 6H, aromatic protons) ;

4.8 (t, lH, CH-CH2) ; 3.85 (m, 12H, OCH3); 2.45 (m, 4H, CH2CH2-N) ; 1.5 (m, 2H, NH2).
the dimaleate is formed in ethanol.
m.p. 130C.
anhydrous content by titration : 98 ~.
15 c) Debenzylati'on''r'oute The compound obtained in example 4 hereinbelow is treated as follows :
In a hydrogenation flask there is put 5.1 g (0.01 mole) of the compound described in exemple 4 in 150 ml of ethanol 20 and 1 g of 10 ~ palladium-on-charcoal. Hydrogenation is carried out at 50C for 3 hours. The catalyst is filtered off and the solvent is evaporated off under reduced pressure. After alkalinisation, 3.75 g (90 % yield) of an oil is extracted with dichloromethane.

ExamPl'e 2 ~ -(3,4-dlmethoxy-phenyl)-3-(1-methyl-propYlami'no)'-propy~
-6,7-di~ethoxy-is'oq'uin'ol'ine' Rl = H R2 = l-methyl-propyl 13 g of the aldehyde, 2.5 g of l-methyl-propylamine and 30 120 ml of ethanol are stirred for 30 minutes'over 1 g of molecular sieve at ambient temperature. The mixture is cooled to 0C and 3 g of sodium borohydride is added. The mixture is stirred overnight at ambient temperature and worked-up as described in the previous examples. 11. 2 g of a yellow oil 35 are isolated. This is dissolved in 100 ml of isopropanol and ll~;iZ998 25.4 ml of 1 N hydrochloric acid ( 1 equivalent) are added to form the hydrochloride. The solution is concentrated to dryness and the residue taken up in the minimum of hot isopropanol and allowed to recrystallize. 6.3 g of product are obtained, m.p. 246C
TLC (methanol/acetone/concentrated hydrochloric acid 90/10/4).
Rf = 0.5 1 spot NMR (base) (CDC13) ~ppm : 8.45 (d, lH, ='CH-N=) ; 7.3-7.5 (m, 2H, aromatic protons) ;
6.15-7 (m, 4H, aromatic protons) ; 4.85 (m, lH,= CH-CH2) ;
3.95 (s, 6H, OCH3) ; 3.75 (s, 6H, OCH3) ; 2.1-3 (m, 5H) ;
1.1-1.6 (m, 3H of which lH is exchangeable NH) ;
0.7-1 (m, 6H).

Example 3 15 1- E- (3,4-dimethoxy-phenyl)-3-cyclohexylamino-propyl~-6,7-dimethoxy-isoquinoline 1 R2 = Cyclohexyl Working as described in example 2 but using cyclohexylamine in place of the l-methyl-propylamine, 8.1 g of the title compound was obtained. Yield 88 ~.
m.p. 135C (ethanol).
NMR (CDCi3) ~ppm : 8.35 (d, lH, CH-N=) ; 7.10 (m, 6H, aromatic protons) ;
4.8 (t, lH,' CH) ; 3.85 (m, 12H, OCH3) ; 2.4 (m, 5H, CH2-'CH2-~-CH ~) ; 1.85 (lH, N-H) ; 1.4 (m, 10H, cyclic CH2).
H
Hydrochloride m.p. ~250C (ethanol) anhydrous content by titration : 100 ~ (2 basic functions) Elemental analysis C2BH36N2O4. HCl (500.5) Calc. C% 72.4 H% 7~76 N% 6.03 Found 72.31 7.65 5.94 'Exampl'e 4 l-El--(3,4-dimethoxy-phenyl)-3-(~-methyl-phenethylamino)-propyl~
-6,7--dimethoxy-isoquinoline Rl R2 = a-methyl-phenethyl 7.6 g (0.02 mole) of the aldehyde are stirred with 2.7 g ~52~8 (0.02 mole) of a-methyl-phenethylamine in 80 ml of absolute ethanol in the presence of 500 mg of molecular sieve (3 A).
After 1 hour of stirring, the mixture is cooled to 0C and 2 q of sodium borohydride is added in small portions. The mixture is stirred for 2 hours at ambient temperature. The reaction médium is then concentrated under reduced pressure, water is added and the whole is extracted with dichloromethane. The extracts are washed with water and dried. The dichloromethane is evaporated off to give 8.5 g of an oil as product. Yield 85 %.
The hydrochloride of this oil is formed using 8.5 ml of 2N
hydrochloric acid in 100 ml of ethanol. The solution is concentrated and the residue is taken up in 50 ml of boiling isopropanol. m.p. 220C.
Anhydrous content by titration : 100 % (2 basic functions).
NMR (CDC13?
~ppm : 8.30 (d, lH, CH-N=) ; 7.05 (m, llH, aromatic protons) ;
4.70 (t, lH~ =CH-CH2) ; 3.85 (m, 12H,'OCH3) ; 2.60 (m, 7H, CH2-'CH2-NH ~ CH2 ~ ) ; 2.30 (lH,NH) ; 1.0 (d, 3H, CH3-CH).
Elemental analysis c3lH36N24 Calc. C~ 69.3 H~ 6.89 N% 5.22 Found 69.1 6.75 5.31 'Exampl'e 5 ~ (3,4-dimethoxy-phenyl)-3-(N-methyl--methyl-benzylamino)-propyl~ -6,7 dimethoxy-'is'o'quinol'i'ne R1 CH3 R2 = a-methyl-benzyl a) Mixture of the two dias'tereoi-somers 11.5 g of the aldehyde are stirred with 3.6 g of a-methyl-benzylamine in 100 ml of ethanol in the presence of 1 g of molecular sieve. After 30 minutes stirring, the reaction mixture was cooled to 0-5C and 2 g of sodium borohydride was added incrementally. Work-up is as described in example 2. 14 g of an oil I are obtained.
7 g of this oil are gently refluxed for 2 1/2 hours in a solution of 18 ml of formic acid and 5 ml of a 30 % aqueous solution of formaldehyde. The reaction mixture is cooled and poured into a saturated solution of sodium carbonate. It is extracted with chloroform and the extracts are washed with water 1.15~3~8 and dried. The extracts are then concentrated to give 7.5 g of an oil which is taken up in isopropanol and allowed to crystallize. The crystals are collected and dried to give 4.3 g of product, m.p. 130C.
IR : 2790 cm 1 N-CH3 NMR (CDC13) ~ppm : 8.35 (d, lH, CH-N=) ; 6.7-7.35 (m, 11H, aromatic protons) ;
4.8 (t, 1H,_'CH-CH2) ; 3.95 (d, 6H, OCH3) ; 3.75 (d, 6H, OCH3) ; 3.65 (q, lH, CH-CH3) ; 3-2 (m, 4H,'CH2-CH2) ;
2.2 (s, 3H, N CH3) ; 1.25 (d, 3H, CH-'CH3).
TLC : 2 spots (dichloromethane/methanol 80J20).
Rf ~0.7 The dihydrochloride is formed in alcohol. The alcohol is evaporated off and the meringue is dried.
b) 'Separ_tion of the diastereoisomers The remaining 7 g of the oil I are chromatographed on a silica gel column (90 g, eluant dichloromethane/methanol 98/2).
There is collected first 2.8 g of a white product which is N-methylated as described in (a) above. There is thus isolated 2.3 g of an oil which crystallizes from isopropanol. m.pr 115C.
TLC : 1 spot (dichIoromethane/methanol 80/20) Rf~ 0.7.
The dihydrochloride is prepared as in (a) above.

''Example 6 1-rl-(3,4-dimethox~-E~enyl)-3-(N-methyl-l-methyl-2-Phenoxy-ethYlamino) -propyl3 -6~7-dimethoixy-isoquinoline R1 = CH3 R2 = 1-methyl-2-phenoxy-ethyl 12 g of the aldehyde, 4.75 g of 1-methyl-2-phenoxy-ethylamine and 125 ml of distilled ethanol are stirred over 1 g of molecular sieve for 30 minutes. The mixture is cooled to 0C and 3 g of sodium borohydride is added in small portions. The reaction mixture is stirred overnight and worked up as in the previous examples to give 13 g of an oil. The 13 g of oil are N-methylated following the method described in example 5. After drying and evaporation, there is obtained 13.5 g of an oil from which the llSZ998 hydrochloride is formed with lN hydrochloric acid in isopropanol.
The solution is evaporated to dryness and the salt is chromatographed on a silica gel column (260 g, eluant dichloro-methane/methanol 95/5) giving 8 g of monohydrochloride isolated in the form of meringue.
TLC : 1 spot (methanol/acetone/conc. hydrochloric acid 90/10/4).
Rf = 0.5 IR (base film : 2800 cm 1 N-CH3) NMR (base) (CDC13) 0 ~ppm : 8.4 (d, lH,''CH=N) ; 6.6-7.5 (m, llH, aromatic protons) ;

5 (m, lH,, CH-CH2) ; 3.75-3.95 (m, 12H, OCH3) ;
2.35 (d, 3H, N-CH3) ; 1.05 (d, 3H, CH-'CH3).

Exampl'e 7 1- G-- (3,4-dimethoxy-phenyl)-3-benzyl-amino-propyl~-6',7-dimethox~-isoqu'i'noline Rl = H R2 = benzyl Working as described in example 2 but using benzylamine in place of the l-methyl-propylamine, the title compound was obtained in 80 % yield.
Hydrochloride m.p. 223C (isopropanol) anydrous content by titration : 99 ~ (2 basic functions) Elemental analysis C29H32N2O4. HCl (508.5) Calc. C~ 68.5 H% 6.50 N% 5.50 Found 68.65 6.32 5.25 NMR (CDC13) ~ppm : 8.3 (d, lH, CH-N=) ; 7.1 (m, llH, aromatic protons) ;
4.8 (t, lH, CH-CH2) ; 3.9 (m, 14H, OCH3 and CH ~ ) ;
2.7 (m, 4H,''CH2'-'CH2-N) ; 2.3 (s, lH, N-H).

' Ex'ample' 8 30 ' 1~-~(3,4-dimethoxy-phe'ny'1')'-3-'(N-methyl'-'4-t.butyl-cyclohexyl'amino)-propy~ -6,7-dimethoxy-1soquinoline Rl = CH3 R2 = 4-t.butyl-cyclohexyl 12 g of the aldehyde, 4.9 g of 4-t-butylcyclohexylamine and 120 ml of distilled ethanol are stirred for 30 minutes on a molecular sieve. Work-up is as described in the previous examples. 13.8 g of an oil are obtained. This oil is then ll -llSZ998 N-methylated as described in Example 5. There is obtained, after work-up, 14 g of a compound which is taken up in boiling diethyl ether and crystallized therefrom. 6.5 g of recrystallized material, m.p. 126C, is obtained.
TLC (methanol/acetone/concentrated hydrochloric acid 90/10/4) 1 spot Rf = 0.6 NMR (CDC13) ~ppm : 8.4 (d, lH, =CH-N=) ; 7.2-7.5 (m, 2H, aromatic protons) ;

6.4-7 (m, 4H, aromatic protons) ; 4.8 (m, 1H,, CH-CH2) ;
4.9 (s, 6H,'OCH3) ; 4.75 (s, 6H, OCH3) ; 2.2 (s, 3H, N-CH3) ; 0.8 (s, 9H, 'tBu).
The monohydrochloride is formed and isolated in a meringue like form.

Example' 9 1- ~3,4-dimethoxy-phenyl)-3-(4-phenyl-cyclohexylamino)-propyl~
-6,7-dimethoxy-isoquinoline "
Rl R2 = 4-phenyl-cyclohexyl 12 g of ~he aldehyde, 5.5 g of 4-phenyl-cyclohexylamine, 120 ml of absolute ethanol and 1 g of molecular sieve ar stirred for 30 minutes. The mixture is cooled and 3 g of sodium borohydride is added. The mixture is stirred overnight and worked-up as in the previous examples. 15.6 g of an oil are obtained. The monohydrochloride is formed in isopropanol with 1 equivalent of N hydrochloric acid. The solution of the monohydrochloride is concentrated to dryness, taken up in the minimum amount of hot isopropanol, and allowed to recrystallize.
8 g of product are obtained, m.p. 160~C.
(HCl) TLC (methanol/acetone/conc. hydrochIoric acid 90/10/4).
1 spot Rf = 0.6 Elemental analysis C34H40N2O4. HCl Calc. C% 70.70 H% 7.11N~ 4.85 Found ' 69.75 7.22 ' 4.68 NMR (base) (CDC13) ~ppm : 8.4 ~d, lH, =CH-N=) ; 6.6-7.5 (m, 11H, aromatic protons) ;
4.95 (m, 1H,= CH-CH2) ; 3.9 (s, 6H, OCH3) ; 3.75 (s, 6H, OCH3) ; 1-3 (m, 15H of which lH is exchangeable).

S~998 Example 10 _~1-(3,4-dimethoxy-phenyl)-3-(1-met~y1-4-~iYdroxy-butylamino) -pxopyl3 -6,-7-dimet~o~-iso:quinoline R1 R2 = 1-methyl-4-hydroxy-butyl 11.7 g of the aldehyde, 3.2 g of 1-methyl-4-hydroxy-butylamine, 120 ml of ethanol and 1 g of molecular sieve are stirred for 30 minutes at ambient temperature. The mixture is cooled and 3 g of sodium borohydride is added in small portions. Work-up is as described in the previous examples.
10 12.3 g of an oil are obtained. The monohydrochloride is formed with 1 equivalent of 1 N hydrochloric acid in isopropanol.
The solution of the monohydrochloride is concentrated to dryness, taken up in the minimum amount of hot isopropanol, and allowed to recrystallize over two days. 7.6 g of product 15 are obtained, m.p. 166C.
TLC (methanol/acetone/concentrated hydrochloric acid 90/10/4).
Rf = 0.6 1 spot Elemental analysis C27H36N2O5- HCl Calc.C% 64.22H% 7.33N% 5.55 20 Found64.00 ' 7.33 - 5.48 NMR (base) (CDC13) ~ppm: 8.45 (d, lH); 6.5-7.6 (m, 6H); 4.95 (m, lH);
4 (d, 6H) ; 3.8 (s, 6H) ; 3.6 (m, 4H); 2.6 (m, 5H);
1.6 (m, 4H) ; 1 (d, 3H).

-The toxlcity of the compounds of the invention has been determined by the usual methods on mice (P.O and I.P.). The corresponding LD 50 values are reported in the following table together with data of papaverine and prenylamine -reference 30 compounds- (figures in mg/kg).

l~S2998 I
N of example I LD 50 P.o. LD 50 I.P.

papaverine 290 98 prenylamine 225 _ 2 ~ 500 ~ 120 3 ~ 450 4 # 900 _ ~ 400 ~ 140 6 # 450 ~ 150

7 # 450 ~ 150

8 ~ 900 ~ 160

9 ~ 1000 ~ 150 ~ 900 ~ 150 ~ solubilised with ascorbic acid.

PHARMACOLOGY
The compounds of the invention show a very favourable activity in the cardiovascular field. For the evaluation of the interest of the compounds of the invention, comparisons have been made with papaverine for the field of action a~d with prenylamine (N(3,3-diphenyl-propyl) ~-methyl phenetylamine) of similar chemical structure.
1/ Cardiac- s-tudies (3 to 5 dogs for each determi-nation) Papaverine is known for its increasing action on heart rate and cardiac work. For this experimentation each batch of 3-5 dogs was treated by the intravenous route by 3mg~kg for prenylamine or by the molecular equivalent for papaverine and for the compounds of examples 2 to 10. No increase of heart rate was noticed either for prenylamine or for compounds of examples 2-10.
As to the cardiac work, it was determined on the same 11 compounds by the calculation of first derivation of left ventricular pressure (dp/dt). Prenylamine and compounds of examples 2, 4, 6, 8 and 10 either decrease dp/dt or did not show any activity in this field ; compounds of examples 3, 5, 7 and 9 show an increase of dp/dt at figures between 11 % and 26 % of the figure obtained for papaverine, which is a strong advantage for the compounds of the invention.

. .

~ - 14 -11529~3 2/ Anti--arrhythmic- effect (Lawson test on mice) For this experimentation each batch of 20 female mice (20-22 g) was treated orally at doses corresponding to 20 %
of the LD 50. The procedure consisted in a chloroform inhalation until apnoea, 45 mn after the administration of the dose, then thoracotomy and measurement of the time in seconds, between apnoea and fibrillation.
If activity of prenylamine is settled at 100, the compounds of the examples 2-10 show an activity comprised between 100 and 187. An appreciable activity was also noticed at the dosage of

10 ~ of LD 50 for compounds of examples 2, 4, 6 and 8 whereas prenylamine had no action at this dose.

3/ Adrenalytic activity on the rat Adrenalytic activity has been determined on batches of 5-6 rats receiving orally 10 % of LD 50 of each compound. After administration, norepinephrine or epinephrine were injected to the rats. If activity of prenylamine is settled at value 100 for reference, results gave values from 60 to 132 (norepinephrine) -best compounds examples 2, 4, 6 and 8- or 48 to 111 (epinephrine) -best compounds example 9-. The values found for papaverine in this experimentation were 44 for norepinephrine and 93 for epinephrine.

4/ Study of hemffdynamic factors (anaesthesied-dogs) After I.V. injection of 3mg/kg of prenylamine or of the molecular equivalent of papaverine or compounds 210 the following hemodynamic factors have been measured or calculated - Blood pressure (mBP).
- Total peripheral resistance calculated from blood pressure and aortic blood flow.
- Coronary blood flow.
The corresponding results are reported in the following table as comparison figures with the action of papaverine on coronary blood flow se~tled as 100.

.. .

~L52~98 ¦ COMPOUND j m B PT P R F B Fj C B F
PRENY. - 48 %- 54 % + 25 % + 50 PAPAV. - 20 - 67 + 70 +100 4 - 22 - 29 + 69 + 58 7 - 36 - 65 - 33 +118 - 33 - 65 + 82 +10~
6 - 40 0 0 + 86 2 - 30 - 29 ~113 0 8 - 46 - 56 _ + 98 9 - 21 - 38 + 54 + 66 - 31 - 38 - 29 + 96 All compounds present an activity on the total peripheral resistance and/or on the coronary blood flow ; this action is all the more interesting that the compounds of the invention do not show the indesirable side effect of papaverine as evidenced in 1/ above.
In the preceding experimentation the various compounds to be used in dissolved form were added a molecular amount of ascorbic acid when they were insoluble in water.
\
P~ESENTATION-POSOLOGY
The compounds of the invention may be administered orally under any therapeutical form e.g. as tablets or gelatine capsules comprising from 20 to 100 mg of active compound per dosage unit, together with an appropriate carrier such as, for instance, lactose.
Injectable forms include phials containing 10 to 50 mg of active ingredient/ if necessary solubilized in water by addition of a therapeutically acceptable acid such as, for instance, ascorbic acid.
Posology in human therapy is from 20 to 200 mg/day in oral form and from 10 to 100 mg/day in injectable (I.V.) form.
The compounds of the invention are to be used as anti-arrhythmics, as coronary and peripheral vasodilators. They have a highIy favourable action on the protection of the myocardic cells against anoxia and prevent the loss of calcium in the myocard.
.;

.-

Claims

The embodiments of the invention in which an exclu-sive property or privilege is claimed are defined as follows:

1. Process of preparation of new 1-[1-(3,4-dimethoxy-phenyl)-3-amino-propyl]-6,7-dimethoxy-isoquinoline having the general formula I:

I

in which R1 represents a hydrogen atom or a methyl group; and R2 represents an alkyl group having from 1 to 5 carbon atoms or a cycloalkyl group having from 5 to 7 carbon atoms, the alkyl or cycloalkyl group optionally being substituted by a hydroxy, phenyl or phenoxy group and the cycloalkyl group optionally being substituted by an alkyl group having from 1 to 5 carbon atoms, and therapeutically acceptable salts thereof, comprising condensing, in a polar solvent, between 0° and 25°C, 1-[1-(3,4-dimethoxy-phenyl)-3-oxo-propyl]-6,7-dimethoxy-isoquinoline of the formula II:

II

with a compound of the general formula HNR1R2 wherein R1 and R2 are as above defined, and reducing the resultant compound.

2. The process of Claim 1, wherein the compound of formula II is condensed with 1-methyl-propylamine and the resulting reaction product is reduced to yield the 1-[1-(3,4-dimethoxy-phenyl)-3-(1-methyl-propylamino)-propyl]-6,7-dimethoxy-isoquinoline.

3. The process of Claim 1, wherein the compound of formula II is condensed with cyclohexylamine and the resulting reaction product is reduced to yield the 1-[1-(3,4-dimethoxy-phenyl)-3-cyclohexylamino-propyl]-6,7-dimethoxy-isoquinoline.

4. The process of Claim 1, wherein the compound of formula II is condensed with .alpha.-methyl-phenethylamine and the resulting reaction product is reduced to yield the 1-[1-(3,i-dimethoxy-phenyl)-3-(.alpha.-methyl-phenethylamino)-propyl]-6,7-dimethoxy-isoquinoline.

5. The process of Claim 1, wherein the compound of formula II is condensed with .alpha.-methyl-benzylamine and the resulting reaction product is reduced to yield the 1-[1-(3,4-dimethoxy-phenyl)-3-(N-methyl-.alpha.-methyl-benzylamino)-propyl]-6,7-dimethoxy-isoquinoline.

6. The process of Claim 1, wherein the compound of formula II is condensed with 1-methyl-2-phenoxy-ethylamine and the resulting reaction product is reduced to yield the 1-[1-(3,4-dimethoxy-phenyl)-3-(N-methyl-1-methyl-2-phenoxy-ethylamino)-propyl]-6,7-dimethoxy-isoquinoline.

7. The process of Claim 1, wherein the compound of formula II is condensed with 1-methyl-propylamine and the resulting reaction product is reduced to yield the 1-[1-(3,4-dimethoxy-phenyl)-3-benzylamino-propyl]-6,7-dimethoxy-isoquinoline.

8. The process of Claim 1, wherein the compound of formula II is condensed with 4-t.butyl-cyclohexylamine and the resulting reaction product is reduced to yield the 1-[1-(3,4-dimethoxy-phenyl)-3-(N-methyl-4-t.butyl-cyclohexylamino)-propyl]-6,7-dimethoxy-isoquinoline.

9. The process of Claim 1, wherein the compound of formula II is condensed with 4-phenyl-cyclohexylamine and the resulting reaction product is reduced to yield the 1-[1-(3,4-dimethoxy-phenyl)-3-(4-phenyl-cyclohexylamino)-propyl]-6,7-dimethoxy-isoquinoline.

10. The process of Claim 1, wherein the compound of formula II is condensed with 1-methyl-4-hydroxy-butylamine and the resulting reaction product is reduced to form the 1-[1-(3,4-dimethoxy-phenyl)-3-(1-methyl-4-hydroxy-butylamino)-propyl]-6,7-dimethoxy-isoquinoline.

11. The new 1-[1-(3,4-dimethoxy-phenyl)-3-amino-propyl]-6,7-dimethoxy-isoquinoline having the general formula I:

I

in which R1 represents a hydrogen atom or a methyl group; and R2 represents an alkyl group having from 1 to 5 carbon atoms or a cycloalkyl group having from 5 to 7 carbon atoms, the alkyl or cycloalkyl group optionally being substituted by a hydroxy, phenyl or phenoxy group and the cycloalkyl group optionally being substituted by an alkyl group having from 1 to 5 carbon atoms, and therapeutically acceptable salts thereof, when prepared by the process defined in Claim 1 or by an obvious chemical equivalent.

12. The 1-[1-(3,4-dimethoxy-phenyl)-3-(1-methyl-propylamino)-propyl]-6,7-dimethoxy-isoquinoline, when prepared by the process defined in Claim 2 or by an obvious chemical equivalent.

13. The 1-[1-(3,4-dimethoxy-phenyl)-3-cyclohexyl-amino-propyl]-6,7-dimethoxy-isoquinoline, when prepared by the process defined in Claim 3 or by an obvious chemical equiva-lent.

14. The 1-[1-(3,4-dimethoxy-phenyl)-3-(.alpha.-methyl-phenethylamino)-propyl]-6,7-dimethoxy-isoquinoline, when prepared by the process defined in Claim 4 or by an obvious chemical equivalent.

15. The 1-[1-(3,4-dimethoxy-phenyl)-3-(N-methyl-.alpha.-methyl-benzylamino)-propyl]-6,7-dimethoxy-isoquinoline, when prepared by the process defined in Claim 5 or by an obvious chemical equivalent.

16. The 1-[1-(3,4-dimethoxy-phenyl)-3-(N-methyl-1-methyl-2-phenoxy-ethylamino)-propyl]-6,7-dimethoxy-iso-quinoline, when prepared by the process defined in Claim 6 or by an obvious chemical equivalent.

17. The 1-[1-(3,4-dimethoxy-phenyl)-3-benzylamino-propyl]-6,7-dimethoxy-isoquinoline, when prepared by the process defined in Claim 7 or by an obvious chemical equiva-lent.

18. The 1-[1-(3,4-dimethoxy-phenyl)-3-(N-methyl-4-t.butyl-cyclohexylamino)-propyl]-6,7-dimethoxy-isoquinoline, when prepared by the process defined in Claim 8 or by an obvious chemical equivalent.

19. The 1-[1-(3,4-dimethoxy-phenyl)-3-(4-phenyl-cyclohexylamino)-propyl]-6,7-dimethoxy-isoquinoline, when prepared by the process defined in Claim 9 or by an obvious chemical equivalent.

20. The 1-[1-(3,4-dimethoxy-phenyl)-3-(1-methyl-4-hydroxy-butylamino)-propyl]-6,7-dimethoxy-isoquinoline, when prepared by the process defined in Claim 10 or by an obvious chemical equivalent.