Isoquinoline derivatives and salts thereof

The invention provides novel compounds and salts thereof, have the structure ##STR1## wherein R.sub.1 is a guianidinobenzoyloxy group and R.sub.2 is a hydrogen atom, a hydroxy, cyano, --COR.sub.3 (wherein R.sub.3 is an amino or lower alkyl group) or --COOR.sub.4 group [wherein R.sub.4 is a hydrogen atom, lower alkyl, phenyl, benzyl or --CH.sub.2 CONR.sub.5 R.sub.6 group (wherein R.sub.5 and R.sub.6 are the same or different and selected from a hydrogen atom and lower alkyl groups)], and wherein R.sub.1 is a hydroxy group and wherein R.sub.2 is a --COR.sub.3 (wherein R.sub.3 is an amino or lower alkyl group) or --COOR.sub.4 group [wherein R.sub.4 is a (C.sub.1, C.sub.3 or C.sub.4) alkyl, phenyl, benzyl or --CH.sub.2 CONR.sub.5 R.sub.6 group (wherein R.sub.5 and R.sub.6 are the same or different and selected from a hydrogen atom and lower alkyl groups)]. The compounds, wherein R.sub.1 is a guanidinobenzoyloxy group, are useful protease inhibitors as anti-trypsin agents.

BACKGROUND OF THE INVENTION 
The present invention relates to novel isoquinoline derivatives and 
pharmaceutically acceptable salts thereof. More specifically, the present 
invention relates to isoquinolyl guanidinobenzoate derivatives and they 
have application as protease inhibitors, in particular as antitrypsin 
agents. Furthermore, most of 5-hydroxyisoquinoline derivatives described 
in this invention, are new compounds and are useful as intermediates for 
the preparation of the isoquinolyl guanidinobenzoate derivatives. 
JP No. 2107/74, U.S. Pat. No. 3,751,447 and Ger. Pat. No. 2050484 claim a 
series of guanidinocaproate. JP No. 1063/86, Eur. Pat. No. 48433 and U.S. 
Pat. No. 4,454,338 claim a series of guanidinobenzoate as useful protease 
inhibitors and anti-complementary agents. JP No. 89640/77, Ger. Pat. No. 
2548886 and U.S. Pat. No. 4,021,472 claim a series of guanidinobenzoates 
as useful protease inhibitors. 
SUMMARY OF THE INVENTION 
It has now been discovered that novel compounds of the formula (I) 
##STR2## 
and pharmaceutically acceptable salts thereof wherein R.sub.1 is 
##STR3## 
and R.sub.2 is a hydrogen atom, a hydroxy, cyano, --COR.sub.3 (wherein 
R.sub.3 is an amino or (C.sub.1 -C.sub.4) alkyl group) or --COOR.sub.4 
group [wherein R.sub.4 is a hydrogen atom, a (C.sub.1 -C.sub.4) alkyl, 
phenyl, benzyl or --CH.sub.2 CONR.sub.5 R.sub.6 group (wherein R.sub.5 and 
R.sub.6 are the same or different and selected from a hydrogen atom and 
(C.sub.1 -C.sub.4) alkyl groups)]. 
These isoquinolyl guanidinobenzoate derivatives are excellent inhibitors 
against proteases and especially useful as anti-trypsin agents. 
Furthermore, the compounds of the formula (I), wherein R.sub.1 is a hydroxy 
group and R.sub.2 is a --COR.sub.3 (wherein R.sub.3 is an amino or 
(C.sub.1 -C.sub.4) alkyl group) or --COOR.sub.4 group [wherein R.sub.4 is 
a (C.sub.1, C.sub.3 or C.sub.4) alkyl, phenyl, benzyl or --CH.sub.2 
CONR.sub.5 R.sub.6 group (wherein R.sub.5 and R.sub.6 are the same or 
different and selected from a hydrogen atom and (C.sub.1 -C.sub.4) alkyl 
groups)], are useful intermediates for the preparation of the isoquinolyl 
guanidinobenzoate derivatives. 
DETAILED DESCRIPTION OF THE INVENTION 
As illustrative examples of "(C.sub.1 -C.sub.4) alkyl groups", there may be 
mentioned methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl and 
tert-butyl. 
The isoquinoline derivatives of the present invention are synthesized as 
shown in FIG. 1. The numerals in the parentheses show the compound numbers 
of isoquinoline derivatives of the present invention. 
##STR4## 
The isoquinolyl guanidinobenzoate derivatives of the formula (II) of the 
present invention can be prepared by a reaction of 4-guanidinobenzoic acid 
or a reactive derivative thereof and a 5-hydroxyisoquinoline derivative of 
the formula (III) or a reactive derivative thereof: 
##STR5## 
wherein R.sub.2 is a hydrogen atom, a hydroxy, cyano, --COR.sub.3 (wherein 
R.sub.3 is an amino or (C.sub.1 -C.sub.4) alkyl group) or --COOR.sub.4 
group [wherein R.sub.4 is a hydrogen atom, a (C.sub.1 -C.sub.4) alkyl, 
phenyl, benzyl or --CH.sub.2 CONR.sub.5 R.sub.6 group (wherein R.sub.5 and 
R.sub.6 are the same or different and selected from a hydrogen atom and 
(C.sub.1 -C.sub.4) alkyl groups)]. 
The reaction of 4-guanidinobenzoic acid and a 5-hydroxyisoquinoline 
derivative (III) can be performed by an application of conventional 
coupling reaction. 
METHOD A-1 
Compounds (II) of the present invention can be prepared by a reaction of 
4-guanidinobenzoic acid or a salt thereof with a 5-hydroxyisoquinoline 
derivative (III) or a salt thereof in the presence of a catalyst or a 
condensing agent, followed by removal of the protective groups as 
required. Suitable examples of the acidic catalysts are sulfuric acid, 
hydrochloric acid, p-toluenesulfonic acid, phosphorous oxychloride, 
polyphosphoric acid and boron trifluoride. And suitable examples of the 
condensing agents are diphenylphosphorylazide, dicyclohexylcarbodiimide 
(DCC), N,N'-carbodiimidazole, N,N'-disuccinimidyl carbonate, 
1-(3-dimethylaminopropyl)-3-ethylcarbodiimide, dimethylformamide, 
diethylacetal, N,N'-dimethylphosphoramidic dichloride and phenyl 
dichlorophosphate. Additionally the basic catalysts, e.g. pyridine, 
triethylamine, diisopropylethylamine, ditert-butylamine, 
dimethylaminopyridine, pyrrolidinopyridine, N-methylmorpholine and 
1,8-diazabicyclo[5,4,0]-7-undecene may be used with above condensing 
agents. 
The solvent can be selected, according to the reaction conditions, from 
pyridine, dimethylformamide, chloroform, dichloromethane, carbon 
tetrachloride, benzene, toluene, xylene, diethyl ether, dioxane, 
tetrahydrofuran, acetonitrile, ethyl acetate, dimethylsulfoxide and water. 
As an example of method A-1, 4-guanidinobenzoic acid and a 
5-hydroxyisoquinoline derivative (III) are allowed to react in the 
presence of DCC in pyridine. The reaction is carried out at -30.degree. to 
100.degree. C. for a few hours to several days. 
METHOD A-2 
Compounds (II) of the present invention can be prepared by a reaction of a 
reactive derivative of 4-guanidinobenzoic acid or a salt thereof, and a 
5-hydroxyisoquinoline derivative (III) or a salt thereof, followed by 
removal of the protective groups as required. 
The reactive derivativers of 4-guanidinobenzoic acid include acid halides 
(e.g. acid chloride and acid bromide), an acid anhydride, mixed acid 
anhydrides with other acids (e.g. trichloroacetic acid, methanesulfonic 
acid, benzenesulfonic acid and isobutoxyformic acid), onium salts (e.g. 
2-bromo-1-pyridinium iodide, 2-chloro-3,5-dinitropyridine and 
2-chloro-1-methylpyridinium iodide) or active esters (e.g. p-nitrophenyl 
ester and N-hydroxysuccinimide ester). 
Additionally the basic catalysts, e.g. pyridine, triethylamine, 
diisopropylethylamine, di-tert-butylamine, dimethylaminopyridine, 
pyrrolidinopyridine, N-methylmorpholine and 
1,8-diazabicyclo[5,4,0]-7-undecene, can be used as required. 
The solvent can be used, according to the reaction conditions, from 
pyridine, chloroform, dichloromethane, carbon tetrachloride, benzene, 
toluene, xylene, diethyl ether, dioxane, tetrahydrofuran, acetonitrile and 
dimethylsulfoxide. 
As an example of method A-2, 4-guanidinobenzoyl chloride and a 
5-hydroxyisoquinoline derivative (III) are allowed to react in pyridine at 
-30.degree. to 100.degree. C. for a few hours to several days. 
METHOD A-3 
Compounds (II) of the present invention can be prepared by a reaction of 
4-guanidinobenzoic acid and a reactive derivative of Compound (III), 
followed by removal of the protective groups as required. 
The reactive derivatives of Compound (III) such as trifluoroacetic acid 
esters or compounds shown by a formula (IV): 
##STR6## 
wherein R.sub.2 is as hereinbefore defined, can be used. 
As protecting groups of carboxy group in Compound (III), conventional ester 
groups such as benzyl, tert-butyl, trimethylsilyl and tetrahydropyranyl 
group may be illustrated. 
For example, the protection by benzyl group is performed by the addition of 
benzyl halide such as benzyl chloride or benzyl bromide to 
5-hydroxy-1-isoquinolinecarboxylic acid or potassium, sodium or 
tetramethylammonium salt thereof in a solvent and the reaction mixture is 
stirring in the presence or absence of a base such as potassium carbonate, 
sodium carbonate or triethylamine at -30.degree. to 100.degree. C. for a 
few hours to several days. 
The solvent can be selected, according to the reaction conditions, from 
chloroform, dichloromethane, carbon tetrachloride, benzene, toluene, 
xylene, dioxane, tetrahydrofuran, acetonitrile, dimethylsulfoxide, 
dimethylformamide, ethyl acetate and hexamethylphosphoric triamide. 
The protected 5-hydroxyisoquinoline compound is allowed to react with a 
4-guanidinobenzoic acid or a reactive derivative thereof by one of said 
methods A-1 to A-3, and the protected isoquinolyl guanidinobenzoate can be 
obtained. 
As a method of de-protection, catalytic reduction can be performed in a 
solution of the protected derivative in a solvent, e.g. methanol, ethanol 
and acetic acid, in the presence of palladium carbon under hydrogen gas 
atmosphere with stirring until no more hydrogen is absorbed. 
Isolation and purification of the isoquinolyl guanidinobenzoate derivative 
(II) of the present invention can be performed by applying conventional 
chemical procedures, such as extraction, condensation, crystallization, 
filtration, recrystallization and various types of chromatography. 
The obtained Compounds (II) of the present invention can be formed salts 
with acids by conventional methods. 
Suitable examples of the acids are sulfuric acid, hydrochloric acid, nitric 
acid, phosphoric acid, hydrobromic acid, carbonic acid, formic acid, 
acetic acid, lactic acid, succinic acid, tartaric acid, malic acid, citric 
acid, methanesulfonic acid, p-toluenesulfonic acid and benzenesulfonic 
acid. 
On the other hands, the compounds of formulae (V) and (VI): 
##STR7## 
wherein R.sub.7 is a (C.sub.1, C.sub.3 or C.sub.4) alkyl, phenyl, benzyl 
or --CH.sub.2 CONR.sub.5 R.sub.6 group (wherein R.sub.5 and R.sub.6 are 
the same or different and selected from a hydrogen atom and (C.sub.1 
-C.sub.4) alkyl groups), are novel 5-hydroxy-1-isoquinolinecarboxylic acid 
esters can be obtained by the condensation of 
5-hydroxy-1-isoquinolinecarboxylic acid and a Compound (VI). 
The condensation can be performed by applying a conventional method. 
METHOD B-1 
Compounds (V) of the present invention can be prepared by a reaction of 
5-hydroxy-1-isoquinolinecarboxylic acid or a salt thereof and a Compound 
(VI) thereof in the presence of a catalyst or a condensing agent. 
Suitable examples of the catalysts are sulfuric acid, hydrochloric acid, 
p-toluenesulfonic acid, phosphorous oxychloride, polyphosphoric acid and 
boron trifluoride. Suitable examples of condensing agents are 
diphenylphosphorylazide, dicyclohexylcarbodiimide (DCC), 
N,N'-carbodiimidazole, N,N'-disuccinimidyl carbonate, 
1-(3-dimethylaminopropyl)-3-ethylcarbodiimide, dimethylformamide 
diethylacetal, N,N'-dimethylphosphoramidic dichloride and phenyl 
dichlorophosphate. Additionally the basic catalysts, e.g. pyridine, 
triethylamine, diisopropylethylamine, di-tert-butylamine, 
dimethylaminopyridine, pyrrolidinopyridine, N-methylmorpholine and 
1,8-diazabicyclo [5,4,0]-7-undecene may be used with above condensing 
agents. 
As an example of method B-1, 5-hydroxy-1-isoquinolinecarboxylic acid is 
allowed to react in a Compound (VI) saturated with HCl gas. The reaction 
is carried out by heating for a few hours to several days. 
METHOD B-2 
Compounds (V) of the present invention can be prepared by a reaction of 
5-hydroxy-1-isoquinolinecarboxylic acid or a salt thereof, and a reactive 
derivative of Compounds (VI) including alkyl halides shown by the formula 
(VII): 
EQU R.sub.7 X (VII) 
(wherein, X is chlorine, bromine or iodine atom), trifluoroacetic acid 
esters of Compound (VI) or compounds shown by the formula (VIII): 
##STR8## 
may be used. 
The reaction condition varies with the properties of the reactive 
derivatives, for example an alkyl halide is reacted with an alkali metal 
salt of 5-hydroxy-1-isoquinolinecarboxylic acid in a solvent with stirring 
at -30.degree. to 100.degree. C. for a few hours to several days. 
Isolation and purification of Compounds (V) from the reaction mixture can 
be performed by applying conventional chemical procedures such as 
extraction, condensation, crystallization, filtration, recrystallization 
and various types of chromatography. The obtained Compounds (V) of the 
present invention may be formed salts with acids by conventional methods, 
as required. Suitable examples of the acids are sulfuric acid, 
hydrochloric acid, nitric acid, phosphoric acid, hydrobromic acid, 
carbonic acid, acetic acid, lactic acid, succinic acid, tartaric acid, 
malic acid, citric acid, methanesulfonic acid, p-toluenesulfonic acid and 
benzenesulfonic acid. 
The inhibitory activity on trypsin in vitro was determined by the methods 
of Muramatsu, et al. described in the Journal of Biochemistry, 58, 214 
(1965). The concentration of compounds shown by the formula (II) which 
inhibits 50% of the hydrolysis of p-tosylarginine methyl ester (TAME) with 
1.5 .mu.g of trypsin or casein with 20 .mu.g of trypsin, respectively, at 
37.degree. C. in 10 minutes are shown in Table 1. 
Test compound numbers and chemical structures of the test compounds and 
control drugs (Gabexate mesylate and Camostat mesylate) are shown below: 
__________________________________________________________________________ 
Chemical structure 
__________________________________________________________________________ 
Compound No. 
1 5-Isoquinolyl 4-guanidinobenzoate dimethanesulfonate 
monohydrate 
##STR9## 
2 1'-Hydroxy-5'-isoquinolyl 4-guanidinobenzoate methanesulfonate 
##STR10## 
3 1'-Cyano-5'-isoquinolyl 4-guanidinobenzoate methanesulfonate 
monohydrate 
##STR11## 
4 1'-Acetyl-5'-isoquinolyl 4-guanidinobenzoate hydrochloride 
##STR12## 
5 1'-Carboxy-5'-isoquinolyl 4-guanidinobenzoate quarterhydrate 
##STR13## 
6 1'-Carbamoyl-5'-isoquinolyl 4-guanidinobenzoate 
methanesulfonate hemihydrate 
##STR14## 
7 1'-Ethoxycarbonyl-5'-isoquinolyl 4-guanidinobenzoate 
hydrochloride 
##STR15## 
8 1'-Propoxycarbonyl-5'-isoquinolyl 4-guanidinobenzoate 
methanesulfonate 
##STR16## 
9 1'-Isopropoxycarbonyl-5'-isoquinolyl 4-guanidinobenzoate 
hydrochloride 
##STR17## 
.circle.10 
1'-Butoxycarbonyl-5'-isoquinolyl 4-guanidinobenzoate 
hydrochloride monohydrate 
##STR18## 
.circle.11 
1'-Benzyloxycarbonyl-5'-isoquinolyl 4-guanidinobenzoate 
hydrochloride monohydrate 
##STR19## 
.circle.12 
1'-(N,N-Dimethylcarbamoyl)methoxycarbonyl-5'-isoquinolyl 
4-guanidinobenzoate hydrochloride 
##STR20## 
Control drugs 
(Gabexate mesylate) 
Ethyl 4-(6-guanidinohexanoyloxy)benzoate methanesulfonate 
##STR21## 
(Camostat mesylate) 
N,N-Dimethylcarbamoylmethyl -p-( -p-guanidinobenzoyloxy)phenyla 
cetate methanesulfonate 
##STR22## 
__________________________________________________________________________ 
TABLE 1 
______________________________________ 
50% inhibitory concentration (M) 
Compound Substrate 
No. TAME Casein 
______________________________________ 
1 5.6 .times. 10.sup.-8 
1.3 .times. 10.sup.-7 
2 6.4 .times. 10.sup.-8 
1.4 .times. 10.sup.-7 
3 5.6 .times. 10.sup.-8 
1.4 .times. 10.sup.-7 
4 5.7 .times. 10.sup.-8 
1.4 .times. 10.sup.-7 
5 6.4 .times. 10.sup.-8 
1.7 .times. 10.sup.-7 
6 5.6 .times. 10.sup.-8 
1.6 .times. 10.sup.-7 
7 5.6 .times. 10.sup.-8 
1.2 .times. 10.sup.-7 
8 9.6 .times. 10.sup.-8 
1.6 .times. 10.sup.-7 
9 1.3 .times. 10.sup.-7 
1.6 .times. 10.sup.-7 
.circle.10 1.5 .times. 10.sup.-7 
2.1 .times. 10.sup.-7 
.circle.11 3.4 .times. 10.sup.-7 
4.1 .times. 10.sup.-7 
.circle.12 6.6 .times. 10.sup.-8 
1.4 .times. 10.sup.-7 
Gabexate 1.5 .times. 10.sup.-5 
2.2 .times. 10.sup.-6 
mesylate 
Camostat 6.5 .times. 10.sup.-8 
1.4 .times. 10.sup.-7 
mesylate 
______________________________________ 
Note) 
TAME: -pTosylarginine methyl ester 
As shown above, the isoquinolyl guanidinobenzoate derivatives (II) of the 
present invention possess excellent anti-trypsin activity and are useful 
for the treatment of disease caused by the activation of protease, for 
example, pancreatic diseases, hemorrhagic diseases and thrombosis. 
The isoquinolyl guanidinobenzoate derivatives (II) of the present invention 
may take various suitable formations, such as tablets, capsules, granules, 
powders and injections with suitable additives, e.g. fillers, carriers or 
diluents and can be administered orally or parenterally.

The present invention is explained by the following examples, however, 
these examples are illustrative for the better understandings of the 
present invention and the present invention is not restricted by these 
examples. 
EXAMPLE 1 
Propyl 5-hydroxy-1-isoquinolinecarboxylate 
Compound No. 13 
The suspension of 3.00 g of 5-hydroxy-1-isoquinolinecarboxylic acid.sup.1) 
in 50 ml of 1-propanol saturated with HCl gas was heated under reflux for 
25 hours. 
The reaction mixture was concentrated under reduced pressure and the 
residue was placed in 50 ml of saturated aqueous sodium hydrogen carbonate 
and extracted three times with 100 ml of ethyl acetate. The combined 
extract was concentrated under reduced pressure and the residue was 
recrystallized from aqueous ethanol to give 1.48 g (yield 40.3%) of the 
title compound. 
Melting point: 148.degree.-150.degree. C. 
FAB-MS: 232 (M+H).sup.+. 
IR: .nu..sup.KBr cm.sup.-1 : 3430, 2970, 1720, 1585, 1460, 1265, 1170, 
1120, 820, 740. 
______________________________________ 
Elemental analysis for C.sub.13 H.sub.13 NO.sub.3 
C (%) H (%) N (%) 
______________________________________ 
Calcd. 67.52 5.67 6.06 
Found 67.42 5.77 6.11 
______________________________________ 
EXAMPLE 2 
Isopropyl 5-hydroxy-1-isoquinolinecarboxylate 
Compound No. 14 
To a suspension of 2.51 g of 5-hydroxy-1-isoquinolinecarboxylic acid in 20 
ml ethanol was added ethanolic potassium hydroxide (KOH 0.88 g, ethanol 20 
ml). The solvent was removed under reduced pressure and the residue was 
suspended in 20 ml of dimethylformamide (DMF). To the suspension was added 
2.26 g of 2-iodopropane and the mixture was stirred for one hour at 
0.degree. C. and 27 hours at room temperature. 
The reaction mixture was poured into 200 ml of 5% aqueous sodium 
thiosulfate and extracted three times with 100 ml ethyl acetate. The 
combined extract was concentrated under reduced pressure and the residue 
was recrystallized from aqueous 2-propanol to give 1.36 g (yield 44.2%) of 
the title compound. 
Melting point: 182.degree.-183.degree. C. 
EI-MS: 231 M.sup.+. 
IR: .nu..sup.KBr cm.sup.-1 : 3450, 2980, 1725, 1585, 1460, 1370, 1270, 
1170, 1105, 930, 820, 740. 
______________________________________ 
Elemental analysis for C.sub.13 H.sub.13 NO.sub.3 
C (%) H (%) N (%) 
______________________________________ 
Calcd. 67.52 5.67 6.06 
Found 67.32 5.62 5.96 
______________________________________ 
EXAMPLE 3 
Butyl 5-hydroxy-1-isoquinolinecarboxylate 
Compound No. 15 
According to the method of example 2, 3.00 g of 
5-hydroxy-1-isoquinolinecarboxylic acid, 1.05 g of potassium hydroxide and 
11.6 g of 1-iodobutane were reacted and purified to give 0.54 g (yield 
13.9%) of the title compound. 
Melting point: 148.degree.-150.degree. C. 
EI-MS: 245 M.sup.+. 
IR: .nu..sup.KBr cm.sup.-1 : 2950, 2570, 1720, 1580, 1450, 1255, 1170, 
1120, 825, 750, 570. 
______________________________________ 
Elemental analysis for C.sub.14 H.sub.15 NO.sub.3 
C (%) H (%) N (%) 
______________________________________ 
Calcd. 68.84 5.78 5.73 
Found 68.79 6.19 5.68 
______________________________________ 
EXAMPLE 4 
Benzyl 5-hydroxy-1-isoquinolinecarboxylate 
Compound No. 16 
According to the method of example 2, 3.00 g of 
5-hydroxy-1-isoquinolinecarboxylic acid, 1.05 g of potassium hydroxide and 
4.16 g of benzyliodide were reacted and purified to give 1.14 g (yield 
25.7%) of the title compound. 
Melting point: 164.degree.-166.degree. C. 
EI-MS: 279 M.sup.+. 
IR: .nu..sup.KBr cm.sup.-1 : 3430, 3040, 2950, 1720, 1580, 1460, 1370, 
1260, 1170, 1120, 950, 820, 750, 695, 565. 
______________________________________ 
Elemental analysis for C.sub.17 H.sub.13 NO.sub.3 
C (%) H (%) N (%) 
______________________________________ 
Calcd. 73.84 4.69 5.02 
Found 73.00 4.78 5.07 
______________________________________ 
EXAMPLE 5 
N,N-Dimethylcarbamoylmethyl 5-hydroxy-1-isoquinolinecarboxylate 
Compound No. 17 
According to the method of example 2, 3.00 g of 
5-hydroxy-1-isoquinolinecarboxylic acid, 1.05 g of potassium hydroxide and 
3.00 g of .alpha.-bromo-N,N-dimethylacetamide were reacted and purified to 
give 2.20 g (yield 50.6%) of the title compound. 
Melting point: 205.degree.-208.degree. C. 
EI-MS: 274 M.sup.+. 
IR: .nu..sup.KBr cm.sup.-1 : 3150, 1720, 1650, 1260, 1160, 1120, 815. 
______________________________________ 
Elemental analysis for C.sub.14 H.sub.14 N.sub.2 O.sub.4 
C (%) H (%) N (%) 
______________________________________ 
Calcd. 61.31 5.14 10.21 
Found 61.11 5.34 10.11 
______________________________________ 
EXAMPLE 6 
1-Acetyl-5-hydroxyisoquinoline 
Compound No. 18 
To a suspension of 3.85 g of sodium ethylate in 50 ml of toluene was added 
803 mg of ethyl 5-hydroxy-1-isoquinolinecarboxylate.sup.1) followed by 
10.6 ml of ethyl acetate. The mixture was heated on the steam-bath with 
stirring for four hours. To the cooled reaction mixture was added 20 ml of 
water followed by 27 ml of six normal hydrochloric acid, and the mixture 
was stirred thoroughly to extract the .beta.-keto ester from the toluene 
layer. The aqueous layer was heated under reflux for one hour and the 
solution was made alkaline with saturated aqueous potassium carbonate and 
extracted five times with 50 ml of ethyl acetate. The extract was 
concentrated under reduced pressure to give the precipitates, which were 
purified by silica gel column chromatography using, as eluent, a mixed 
solvent of hexane:ethyl acetate=3:1 to give 430 mg (yield 63.1%) of the 
title compound. 
Melting point: 149.degree.-152.degree. C. 
FAB-MS: 188 (M+H).sup.+. 
IR: .nu..sup.KBr cm.sup.-1 : 3430, 1695, 1585, 1255. 
______________________________________ 
Elemental analysis for C.sub.11 H.sub.9 NO.sub.2 
C (%) H (%) N (%) 
______________________________________ 
Calcd. 70.53 4.85 7.48 
Found 70.55 4.92 7.36 
______________________________________ 
EXAMPLE 7 
5-Hydroxy-1-isoquinolinecarboxamide 
Compound 19 
The suspension of 3.00 g of 1-cyano-5-benzoyloxyisoquinoline.sup.1) in 50 
ml of methanol saturated with HCl gas was stirred at room temperature for 
20 hours. The precipitates were collected by filtration and suspended in 
50 ml of methanol. 
The mixture was heated at 50.degree. C. for three hours and concentrated 
under reduced pressure. The residue was mixed with saturated aqueous 
sodium hydrogen carbonate and the formed precipitates were collected and 
washed with water and acetone successively. The precipitates were 
recrystallized from acetone to give 650 mg (yield 31.7%) of the title 
compound. 
Melting point: 222.degree.-225.degree. C. 
EI-MS: 188 M.sup.+. 
IR: .nu..sup.KBr cm.sup.-1 : 3400, 3130, 1670, 1590, 1460, 1395, 1340, 
1275, 820. 
______________________________________ 
Elemental analysis for C.sub.11 H.sub.9 NO.sub.2 
C (%) H (%) N (%) 
______________________________________ 
Calcd. 63.78 4.23 14.94 
Found 63.50 4.43 14.93 
______________________________________ 
EXAMPLE 8 
5-Isoquinolyl 4-guanidinobenzoate dimethanesulfonate monohydrate 
Compound No. 1 
To a chilled solution of 3.51 g of 4-guanidinobenzoic acid hydrochloride in 
60 ml of pyridine was added 4.25 g of dicyclohexylcarbodiimide (DCC) and 
the mixture was stirred for one hour at 0.degree. C. Then a solution of 
2.37 g of 5-hydroxyisoquinoline.sup.1) in 30 ml of pyridine was added to 
this reaction mixture over 30 minutes period, and stirred for another one 
hour. A reaction mixture was gradually raised to room temperature and 
stirred for 20 hours. 
The precipitated crystals were collected by filtration, washed with 
pyridine and acetone successively. The crystals were dissolved in 100 ml 
of methanol and the insoluble materials were filtered off. The filtrate 
was concentrated under reduced pressure to give 2.61 g of residue, which 
was purified by silica gel column chromatography using, as eluent, a mixed 
solvent of CHCl.sub.3 :CH.sub.3 OH:CH.sub.3 COOH=10:1:1, to give 2.54 g of 
the acetate. 
The acetate was suspended in ethanol and methanesulfonic acid was added to 
this suspension to make a clear solution. To the solution, 100 ml of ether 
was added and the formed crystals were collected. The crystals were 
recrystallized from ethanol to give 2.63 g (yield 31.3%) of the title 
compound. 
Melting point: 182.degree.-184.degree. C. 
FAB-MS: 307 (M+H).sup.+, 399 (M+Gly+H).sup.+. 
IR: .nu..sup.KBr cm.sup.-1 : 3340, 3130, 1730, 1695, 1650, 1615, 1575, 
1265, 1240, 1210, 1100, 1040, 840, 775, 540. 
______________________________________ 
Elemental analysis for C.sub.17 H.sub.14 N.sub.4 O.sub.2.2CH.sub.3 
SO.sub.3 H.H.sub.2 O 
C (%) H (%) N (%) S (%) 
______________________________________ 
Calcd. 44.18 4.68 10.85 12.41 
Found 44.10 4.53 10.97 12.72 
______________________________________ 
EXAMPLE 9 
1'-Hydroxy-5'-isoquinolyl 4-guanidinobenzoate methanesulfonate 
Compound No. 2 
According to the method of example 8, 2.70 g of 4-guanidinobenzoic acid 
hydrochloride, 2.60 g of DCC and 2.00 g of 1,5-isoquinolinediol.sup.1) 
were reacted. 
The precipitates were collected by filtration and suspended in methanol and 
methanesulfonic acid was added to this suspension. The insoluble materials 
were filtered off and the filtrate was concentrated under reduced pressure 
to give crystals, which were recrystallized from methanol to give 0.10 g 
(yield 2.0%) of the title compound. 
Melting point: 209.degree.-213.degree. C. 
FAB-MS: 323 (M+H).sup.+. 
IR: .nu..sup.KBr cm.sup.-1 : 3400, 3200, 1740, 1700, 1660, 1640, 1610, 
1570, 1515, 1480, 1400, 1265, 1230, 1170, 1040, 740. 
______________________________________ 
Elemental analysis for C.sub.17 H.sub.14 N.sub.4 O.sub.3.CH.sub.3 
SO.sub.3 H 
C (%) H (%) N (%) S (%) 
______________________________________ 
Calcd. 51.67 4.34 13.39 7.66 
Found 51.51 4.27 13.31 7.74 
______________________________________ 
EXAMPLE 10 
1'-Cyano-5'-isoquinolyl 4-guanidinobenzoate methanesulfonate monohydrate 
Compound No. 3 
According to the method of example 8, 0.65 g of 4-guanidinobenzoic acid 
hydrochloride, 0.78 g of DCC and 0.51 g of 
1-cyano-5-hydroxyisoquinoline.sup.1) were reacted. 
The reaction mixture was filtered and the filtrate was concentrated under 
reduced pressure. The condensed solution was mixed with 30 ml of saturated 
aqueous sodium hydrogen carbonate and the formed precipitates were 
collected and washed with water and acetone successively to give 1.17 g of 
the carbonate. 
The carbonate was suspended in nine ml of DMF and dissolved by addition of 
0.69 g of methanesulfonic acid and 30 ml of ether was added to the 
solution. 
The resulting crystals were collected and recrystallized from methanol to 
give 0.30 g (yield 22.3%) of the title compound. 
Melting point: 220.degree.-225.degree. C. 
FAB-MS: 332 (M+H).sup.+. 
IR: .nu..sup.KBr cm.sup.-1 : 3370, 3180, 2240, 1745, 1685, 1605, 1580, 
1415, 1400, 1255, 1200, 1175, 1145, 1060, 760. 
______________________________________ 
Elemental analysis for C.sub.18 H.sub.13 N.sub.5 O.sub.2.CH.sub.3 
SO.sub.3 H.H.sub.2 O 
C (%) H (%) N (%) S (%) 
______________________________________ 
Calcd. 51.23 4.30 15.72 7.20 
Found 51.37 4.04 15.77 7.43 
______________________________________ 
EXAMPLE 11 
1'-Acetyl-5'-isoquinolyl 4-guanidinobenzoate hydrochloride 
Compound No. 4 
According to the method of example 10, 0.70 g of 4-guanidinobenzoic acid 
hydrochloride, 0.67 g of DCC and 0.61 g of 1-acetyl-5-hydroxyisoquinoline, 
prepared by the method of example 6, were reacted and worked-up to give 
0.77 g of the carbonate. 
The carbonate was purified by silica gel column chromatography using, as 
eluent, a mixed solvent of CHCl.sub.3 :CH.sub.3 OH:CH.sub.3 COOH=10:1:1 to 
give the acetate. The acetate was suspended in 2-propanol and dissolved by 
addition of hydrochloric acid and this solution was concentrated under 
reduced pressure to give the hydrochloride. The hydrochloride was 
recrystallized from 2-propanol to give 0.17 g (yield 13.3%) of the title 
compound. 
Melting point: 210.degree.-211.degree. C. (dec.). 
FAB-MS: 350 (M+H).sup.+, 
IR: .nu..sup.KBr cm.sup.-1 : 3430, 3100, 1740, 1690, 1235. 
______________________________________ 
Elemental analysis for C.sub.19 H.sub.16 N.sub.4 O.sub.3.HCl 
C (%) H (%) N (%) 
______________________________________ 
Calcd. 59.30 4.45 14.56 
Found 59.06 4.59 14.34 
______________________________________ 
EXAMPLE 12 
1'-Carboxy-5'-isoquinolyl 4-guanidinobenzoate quarterhydrate 
Compound No. 5 
According to the method of example 8, 3.88 g of 4-guanidinobenzoic acid 
hydrochloride, 4.30 g of DCC and 5.30 g of benzyl 
5-hydroxy-1-isoquinolinecarboxylate prepared by the method of example 4 
were reacted. 
The reaction mixture was filtered and 400 ml of ether was added to the 
filtrate to form precipitates which were recrystallized from 150 ml of 
ethanol to give 3.65 g of 1'-benzyloxycarbonyl-5'-isoquinolyl 
4-guanidinobenzoate hydrochloride monohydrate (melting point: 
112.degree.-113.degree. C.). 
The mixture of 3.50 g of the above mentioned compound and 0.30 g of 5% 
palladium carbon in 50 ml of methanol were stirred in hydrogen gas 
atmosphere for 20 hours at room temperature. One hundred ml of acetic acid 
was added to this reaction mixture and the insoluble materials were 
filtered off and the solvent was removed under reduced pressure. The 
residue was recrystallized from 300 ml of 50% methyl cellosolve to give 
1.03 g (yield 16.8%) of the title compound. 
Melting point: 225.degree.-235.degree. C. (dec.), 
FAB-MS: 351 (M+H).sup.+, 
IR: .nu..sup.KBr cm.sup.-1 : 3450, 3150, 1730, 1700, 1610, 1555, 1405, 
1275, 1240, 1230, 1070, 820, 760. 
______________________________________ 
Elemental analysis for C.sub.18 H.sub.14 N.sub.4 O.sub.4.1/4H.sub.2 O 
C (%) H (%) N (%) 
______________________________________ 
Calcd. 60.93 4.12 15.79 
Found 60.79 3.97 15.62 
______________________________________ 
EXAMPLE 13 
1'-Carbamoyl-5'-isoquinolyl 4-guanidinobenzoate methanesulfonate 
hemihydrate 
Compound No. 6 
According to the method of example 8, 0.55 g of 4-guanidinobenzoic acid 
hydrochloride, 0.53 g of DCC and 0.48 g of 
5-hydroxy-1-isoquinolinecarboxamide, prepared by the method of example 7, 
were reacted. 
The reaction mixture was filtered, the filtrate was mixed with 400 ml of 
ether to form an oily residue. 
The oily residue was purified by silica gel column chromatography using, as 
eluent, a mixed solvent of CHCl.sub.3 : CH.sub.3 OH: CH.sub.3 COOH=10:3:1. 
The obtained residue was dissolved in methanol and mixed with a saturated 
aqueous sodium hydrogen carbonate and formed precipitates were collected 
and washed with water and acetone successively to give the carbonate. 
The carbonate was suspended in methanol and a methanesulfonic acid was 
added dropwise to make the suspension acidic. The insoluble materials were 
filtered off and the filtrate was allowed to stand to give 0.18 g (yield 
20.0%) of the title compound. 
Melting point: 264.degree.-268.degree. C. (dec.), 
FAB-MS: 350 (M+H).sup.+, 
IR: .nu..sup.KBr cm.sup.-1 : 3420, 3170, 1730, 1680, 1575, 1520, 1410, 
1275, 1240, 1225, 1165, 1040, 765, 620. 
______________________________________ 
Elemental analysis for C.sub.18 H.sub.15 N.sub.5 O.sub.3.CH.sub.3 
SO.sub.3 H.1/2H.sub.2 O 
C (%) H (%) N (%) S (%) 
______________________________________ 
Calcd. 50.22 4.44 15.41 7.06 
Found 50.65 4.49 15.32 6.88 
______________________________________ 
EXAMPLE 14 
1'-Ethoxycarbonyl-5'-isoquinolyl 4-guanidinobenzoate hydrochloride 
Compound No. 7 
According to the method of example 10, 5.00 g of 4-guanidinobenzoic acid 
hydrochloride, 4.70 g of DCC and 5.00 g of ethyl 
5-hydroxy-1-isoquinolinecarboxylate.sup.1) were reacted to give 6.40 g of 
the carbonate. To the suspension of the carbonate in 100 ml of methanol 
was added seven ml of methanol saturated with HCl gas and the insoluble 
materials were filtered off. The filtrate was concentrated under reduced 
pressure to give a corresponding crude hydrochloride and recrystallized 
from ethanol to give 0.84 g (yield 8.7%) of the title compound. 
Melting point: 187.degree.-192.degree. C. 
FAB-MS: 470 (M+Gly+H).sup.+. 
IR: .nu..sup.KBr cm.sup.-1 : 3300, 2980, 1730, 1680, 1630, 1600, 1570, 
1510, 1460, 1270, 1230, 1160, 1060, 1010, 760. 
______________________________________ 
Elemental analysis for C.sub.20 H.sub.18 N.sub.4 O.sub.4.HCl 
C (%) H (%) N (%) 
______________________________________ 
Calcd. 57.91 4.62 13.51 
Found 57.46 4.73 13.72 
______________________________________ 
EXAMPLE 15 
1'-Propoxycarbonyl-5'-isoquinolyl 4-guanidinobenzoate methanesulfonate 
Compound No. 8 
According to the method of example 8, 1.08 g of 4-guanidinobenzoic acid 
hydrochloride, 1.03 g of DCC and 1.16 g of propyl 
5-hydroxy-1-isoquinolinecarboxylate, prepared by the method of example 1, 
were reacted to give 1.71 g of the carbonate. 
By the same method of example 11, the carbonate was converted to 0.98 g 
(yield 40.8%) of the title compound. 
Melting point: 175.degree.-177.degree. C. 
FAB-MS: 393 (M+H).sup.30. 
IR: .nu..sup.KBr cm.sup.-1 : 3300, 3200, 1740, 1700, 1575, 1235, 1210, 
1170, 1050. 
______________________________________ 
Elemental analysis for C.sub.21 H.sub.20 N.sub.4 O.sub.4.CH.sub.3 
SO.sub.3 H 
C (%) H (%) N (%) S (%) 
______________________________________ 
Calcd. 54.09 4.95 11.47 6.56 
Found 54.03 5.00 11.45 6.73 
______________________________________ 
EXAMPLE 16 
1'-Isopropoxycarbonyl-5'-isoquinolyl 4-guanidinobenzoate hydrochloride 
Compound No. 9 
According to the method of example 8, 1.40 g of 4-granidinobenzoic acid 
hydrochloride, 1.55 g of DCC and 1.50 g of isopropyl 
5-hydroxy-1-isoquinolinecarboxylate, prepared by the method of example 2, 
were reacted. The reaction mixture was mixed with 50 ml of ether to give 
crystals which were recrystallized from ethanol-ether to give 1.51 g 
(yield 54.2%) of the title compound. 
Melting point: 177.degree.-180.degree. C. 
FAB-MS: 393 (M+H).sup.30. 
IR: .nu..sup.KBr cm.sup.-1 : 3500, 2980, 1730, 1680, 1625, 1600, 1570, 
1270, 1230, 1170, 1065, 760, 745. 
______________________________________ 
Elemental analysis for C.sub.21 H.sub.20 N.sub.4 O.sub.4.HCl 
C (%) H (%) N (%) 
______________________________________ 
Calcd. 58.81 4.94 13.06 
Found 58.63 4.99 12.96 
______________________________________ 
EXAMPLE 17 
1'-Butoxycarbonyl-5'-isoquinolyl 4-guandinobenzoate hydrochloride 
monohydrate 
Compound No. 10 
According to the method of example 8, 0.88 g of 4-guanidinobenzoic acid 
hydrochloride, 0.84 g of DCC and 1.00 g of butyl 
5-hydroxy-1-isoquinolinecarboxylate, prepared by the method of example 3, 
were reacted. The reaction mixture was filtered and the filtrate was mixed 
with 60 ml of ether to give precipitates. The precipitates were purified 
by silica gel column chromatography using, as eluent, a mixed solvent of 
CHCl.sub.3 :CH.sub.3 OH:CH.sub.3 COOH=10:1:1. The solvent was removed 
under reduced pressure and the residue was triturated with acetone to give 
0.30 g (yield 16.2%) of the title compound. 
Melting point: 162.degree.-171.degree. C. 
FAB-MS: 407 (M+H).sup.30 . 
IR: .nu..sup.KBr cm.sup.-1 : 3310, 2960, 1730, 1680, 1570, 1270, 1230, 
1165, 1060, 760. 
______________________________________ 
Elemental analysis for C.sub.22 H.sub.22 N.sub.4 O.sub.4.HCl.H.sub.2 O 
C (%) H (%) N (%) 
______________________________________ 
Calcd. 57.33 5.47 12.16 
Found 57.19 5.24 11.97 
______________________________________ 
EXAMPLE 18 
1'-Benzyloxycarbonyl-5'-isoquinolyl 4-guanidinobenzoate hydrochloride 
monohydrate 
Compound No. 11 
According to the method of example 12, 0.77 g of 4-guanidinobenzoic acid 
hydrochloride, 0.86 g of DCC and 1.00 g of benzyl 
5-hydroxy-1-isoquinolinecarboxylate, prepared by the method of example 4, 
were reacted and obtained 0.87 g (yield 49.1%) of the title compound. 
Melting point: 112.degree.-113.degree. C. 
FAB-MS: 441 (M+H).sup.+ 
IR: .nu..sup.KBr cm.sup.-1 : 3370, 3150, 1740, 1680, 1600, 1575, 1275, 
1230, 1170, 1060, 1020, 760, 750, 700. 
______________________________________ 
Elemental analysis for C.sub.25 H.sub.20 N.sub.4 O.sub.4.HCl.H.sub.2 O 
C (%) H (%) N (%) 
______________________________________ 
Calcd. 60.67 4.68 11.32 
Found 60.68 4.80 11.55 
______________________________________ 
EXAMPLE 19 
1'-(N,N-dimethylcarbamoyl)methyloxycarbonyl-5'-isoquinolyl 
4-guanidinobenzoate hydrochloride 
Compound No. 12 
According to the method of example 11, 1.00 g of 4-guanidinobenzoic acid 
hydrochloride, 1.00 g of DCC and 1.40 g of N,N-dimethylcarbamoylmethyl 
5-hydroxy-1-isoquinolinecarboxylate, prepared by the method of example 5, 
were reacted and worked-up to give 1.36 g (yield 62.1%) of the title 
compound. 
Melting point: 184.degree.-187.degree. C. 
FAB-MS: 436 (M+H).sup.+. 
IR: .nu..sup.KBr cm.sup.-1 : 3280, 3150, 1760, 1740, 1670, 1600, 1570, 
1510, 1170, 1150, 1120, 1050, 820. 
______________________________________ 
Elemental analysis for C.sub.22 H.sub.21 N.sub.5 O.sub.5.HCl 
C (%) H (%) N (%) 
______________________________________ 
Calcd. 56.00 4.70 14.84 
Found 56.19 4.62 14.46 
______________________________________ 
REFERENCE 
1) V. Georgian et al., J. Org. Chem., 27, 4571 (1962). 
BRIEF DESCRIPTION OF THE DRAWINGS 
FIG. 1 shows schema for the synthesis of isoquinoline derivatives of the 
present invention. The numerals in the parentheses show the compound Nos. 
is isoquinoline derivatives of the present invention.