This invention relates to novel compounds of the formula I!, ##STR1## wherein R.sup.1 and R.sup.2 are the same or different and each represents a lower alkoxy group; A and B are the same or different and each represents a lower alkylene group. The compounds of this invention have affinities for sigma receptors and are useful for therapeutic agents for cerebral neural function disorders such as dementia, depression, schizophrenia and anxiety neurosis, diseases accompanying abnormal immune response and cryptorrhea, digestive ulcer, etc.

TECHNICAL FIELD 
The present invention relates to novel 1,4-(diphenylalkyl)piperazine 
derivatives which have affinities for sigma receptors and are useful for 
therapeutic agents for cerebral neural function disorders such as 
dementia, depression, schizophrenia and anxiety neurosis, diseases 
accompanying abnormal immune response and cryptorrhea, digestive ulcer, 
etc. 
BACKGROUND ART 
Many studies on sigma receptors have recently been made, and it has been 
found out that compounds having high affinities for the sigma receptor are 
useful for therapeutic agents for cerebral neural function disorders such 
as dementia, depression, schizophrenia and anxiety neurosis, diseases 
accompanying abnormal immune response and cryptorrhea, digestive ulcer, 
etc. (Journal of Neuropsychiatry, 1, 7-15 (1989); Eur. J. Biochem., 200, 
633-642 (1991); J. Pharmacol. Exp. Ther., 255, 1354-1359 (1990)). 
On the other hand, 1,4-(diphenylalkyl)piperazine derivatives are reported 
to have affinities for sigma receptors (WO91/09594). However, this report 
mainly relates to the compounds which have no substituents at a phenyl 
ring, and it does not recite studies about influence on affinities for 
sigma receptors by introducing substituents into the phenyl ring. 
The following prior arts disclose compounds whose chemical structures are 
similar to those of the compounds of this invention, though different from 
this invention in objects, actions and effects. Many 
1,4-(diphenylalkyl)piperazine derivatives having no substituents at both 
of two phenyl rings and having substituents at both of two phenyl rings 
have already been synthesized (Chem. Ber., 100, 3045 (1967); J. Pharm. 
Sci., 72, 304 (1983)). However, there are few reports of research about 
1,4-(diphenylalkyl)piperazine derivatives having substituents at only one 
phenyl ring and having no substituents at the other phenyl ring. 
For example, only a compound wherein the 3rd-position of the phenyl ring is 
substituted by methoxy group and the 2nd-position is substituted by 
hydroxyl group (Pharmazie, 29, 189 (1970)) and a compound wherein the 
2nd-, 3rd- and 4th-positions of one phenyl ring are substituted by methoxy 
groups (Japanese Patent Laid-open Publication No. 55-83771) are reported 
as compounds wherein one phenyl ring has no substituents and the other 
phenyl ring has alkoxy groups. Of course, affinities for sigma receptors 
have not been reported about these compounds. 
It has not been studied yet how affinities for sigma receptors vary by 
introducing substituents into the phenyl ring of 
1,4-(diphenylalkyl)piperazine derivatives, and it was an important subject 
to find a compound having a high affinity for sigma receptors by 
introducing substituents into the phenyl ring. 
In addition, it has not been studied fully to introduce at least one 
substituent into only one phenyl ring of 1,4-(diphenylalkyl)piperazine 
derivatives, and it was an interesting subject to synthesize and study 
such compounds. 
The inventors synthesized novel 1,4-(diphenylalkyl)piperazine derivatives 
having specific substituents at only one phenyl ring and examined effects 
of the compounds on sigma receptors. As the result of the examination, 
compounds having two alkoxy groups at only one phenyl ring were found to 
have high affinities for sigma receptors. 
Furthermore it was found that these compounds have not only high affinities 
for sigma receptors but also improving effects on learning disorder due to 
cerebrovascular disorder and increasing effects on the amount of 
intracerebral acetylcholine, and that the compounds are particularly 
useful for therapeutic agents for cerebral neural function disorders. 
SUMMARY OF THE INVENTION 
This invention relates to the compounds represented by following formula 
I!, salts thereof (hereinafter referred to as "the compounds of this 
invention") and therapeutic agents for cerebral neural function disorders 
which comprise them as active ingredients: 
##STR2## 
wherein, R.sup.1 and R.sup.2 are the same or different and each represents 
a lower alkoxy group; "A" and "B" are the same or different and each 
represents a lower alkylene group. 
The same definition is applied hereinafter. 
DETAILED DESCRIPTION OF THE INVENTION 
The terms defined above are explained as follows in more detail; 
The term "lower alkoxy" stands for straight or branched alkoxy having 1 to 
6 carbon atoms exemplified by methoxy, ethoxy, propoxy, isopropoxy, 
t-butoxy and hexyloxy. 
The term "lower alkylene" stands for straight or branched alkylene having 1 
to 6 carbon atoms exemplified by methylene, ethylene, propylene, butylene, 
(dimethyl)methylene and (diethyl)methylene. 
The salts of the compound of this invention are pharmaceutically acceptable 
salts such as hydrochloride, sulfate, maleate and fumarate. 
Preferred examples of the groups defined above are explained as follows in 
detail. 
Preferred examples of the lower alkylene groups "A" and "B" are straight 
alkylene group(s) having 2 to 4 carbon atoms, that is, ethylene, propylene 
and/or butylene. Preferred examples of the combination of "A" and "B" are 
shown below; 
"A" is propylene and "B" is ethylene, 
both "A" and "B" are propylene, 
both "A" and "B" are ethylene, 
"A" is butylene and "B" is ethylene. 
Particularly preferred examples of the combination of "A" and "B" are shown 
below; 
"A" is propylene and "B" is ethylene, 
both "A" and "B" are propylene. 
Each of R.sup.1 and R.sup.2 is preferably a methoxy group. In particular, a 
compound wherein methoxy groups substitute at vicinal positions in one 
phenyl ring is preferable. The most preferred example is a compound 
wherein methoxy groups substitute at the 3rd- and 4th-positions 
respectively. 
Preferred examples of practical compounds are 
1-2-(3,4-dimethoxyphenyl)ethyl!-4-(3-phenylpropyl)piperazine, 
1-2-(3,4-dimethoxyphenyl)ethyl!-4-(2-phenylethyl)piperazine, 
1-2-(3,4-dimethoxyphenyl)ethyl!-4-(4-phenylbutyl)piperazine, 
1-3-(3,4-dimethoxyphenyl)propyl!-4-(3-phenylpropyl)piperazine, or salts 
thereof. 
Particularly preferred examples of compounds are 
1-2-(3,4-dimethoxyphenyl)ethyl!-4-(3-phenylpropyl)piperazine, 
1-3-(3,4-dimethoxyphenyl)propyl!-4-(3-phenylpropyl)piperazine, or salts 
thereof. 
Typical synthetic methods for preparing the compounds of this invention are 
shown in the following reaction schemes 1) and 2). 
##STR3## 
wherein X is halogen or a reactive group exemplified by a lower 
alkanesulfonyloxy group. The same definition applies to the reaction 
below. 
In this method, the compound of the formula V! is prepared by reacting the 
compound of the formula IV! with 2-bromoethanol. The compound of the 
formula V! is reacted with thionyl chloride, methanesulfonyl chloride, 
etc. to give the compound of the formula VI!, which is then reacted with 
the amine derivative of the formula VII! to give the compound of this 
invention represented by the formula I!. 
##STR4## 
In this method, the reaction order of method 1) is reversed, and reaction 
conditions, etc. are the same as those of method 1). 
The compounds prepared by the above methods can be converted into their 
salts as previously mentioned by conventional method. 
Some of the compounds of the formula I! have optical isomers, and these 
isomers are also included in this invention. 
In order to study the utility of the compounds of this invention, an 
experiment was performed to examine affinities of the compounds for sigma 
receptors. Details are shown in the article of Pharmacological Test 
described later in this specification. The inventors examined affinities 
of the compounds for sigma receptors using .sup.3 H!(+)-SKF-10047 or 
.sup.3 H!(+)-PTZ as labeled ligands. As the result of the examination, 
the compounds of this invention were found to exhibit high affinities for 
sigma receptors. 
Since compounds increasing the amount of intracerebral acetylcholine are 
reported to be useful for therapeutic agents for dementia, etc. (The New 
England Journal of Medicine, 315, 1241-1245 (1986)), the amount of 
acetylcholine in rat brain was then measured according to the report of 
Matsuno et al. (Brain Research, 575, 315-319 (1992)). As the result of the 
measurement, the compounds of this invention were found to exhibit 
increasing effects on the amount of acetylcholine. 
In addition, an experiment was performed using learning disorder models 
caused by ischemia known as disease models of dementia caused by 
cerebrovascular disorder, that is, rats in transient ischemic condition by 
blockading artery according to the method of Pulsinelli et al. (Stroke, 
10, 267 (1979)). Evaluating the result of the experiment according to the 
method of Yasumatsu et al, (Folia Pharmacologica Japonica, 90, 321 
(1987)), the compounds of this invention were found to have improving 
effects on learning disorders. 
From the results of the above pharmacological tests, it was found that the 
compounds of this invention have high affinities for sigma receptors and 
that the compounds have wide pharmaceutical uses for therapeutic agents 
for diseases in which sigma receptors are concerned, for example, cerebral 
neural function disorders such as dementia, depression, schizophrenia and 
anxiety neurosis, diseases accompanying abnormal immune response and 
cryptorrhea, digestive ulcer, etc. It was also found that the compounds 
have increasing effects on the amount of intracerebral acetylcholine and 
improving effects on learning disorders due to cerebrovascular disorder. 
From these findings, the compounds were proved to be particularly useful 
for therapeutic agents for cerebral neural function disorders. 
By the way, certain piperazine derivatives are reported to have a 
morphine-like physical dependence (Examined Japanese Patent Publication 
No. 61-33827). Such effect is not favorable for medicaments. Accordingly, 
an experiment was performed to examine whether the compounds of this 
invention exhibit morphine-like effects. A compound having the 
morphine-like effect is known to have a high affinity for .mu. receptors, 
and if the affinity for .mu. receptors is low, the morphine-like effect of 
the compound is judged to be also low. Affinities of the compounds of this 
invention for .mu. receptors were examined using .sup.3 H!DAMGO as a 
labeled ligand. As the result of the examination, it was found that 
affinities of the compounds of this invention for .mu. receptors are low 
and that the compounds substantially exhibit no morphine-like effects. 
In order to apply one compound to a medicament, it is preferable that the 
difference between the amount for exhibiting effect and the amount for 
exhibiting side-effect is large. That is to say, it is preferable that the 
affinity for sigma receptors is high and the affinity for .mu. receptors 
is low in this invention, and the experimental results described later 
demonstrate that the compounds of this invention are excellent as 
medicaments. 
The compounds of this invention can be administered orally or parenterally. 
Examples of dosage forms are tablet, capsule, soft capsule, granule, 
injection, etc. The preparations can be formulated by the conventional 
methods. For example, oral preparations such as a tablet, a capsule, a 
soft capsule and granule can be produced, if necessary, by adding diluents 
such as lactose, starch, crystalline cellulose or vegetable oil; 
lubricants such as magnesium stearate or talc; binders such as 
hydroxypropylcellulose or polyvinyl pyrrolidone; a disintegrator such as 
calcium carboxymethylcellulose; coating agents such as 
hydroxypropylmethylcellulose, macrogol or silicone resin; or a film 
forming agent such as gelatin coat. The dosage is adjusted depending on 
symptoms, dosage form, etc., but the usual daily dosage is 1 to 1000 mg, 
which can be given in one or a few divided doses.

THE BEST EMBODIMENT OF THE INVENTION 
Reference Examples (Preparation of Intermediates) 
Reference Example 1 
N,N-Bis(2-hydroxyethyl)-2-(3,4-dimethoxyphenyl)ethylamine (reference 
compound No. 1-1) 
##STR5## 
To a solution of 2-(3,4-dimethoxyphenyl)ethylamine (20 g) and 
2-bromoethanol (73.4 g) in ethanol (250 ml) was added potassium carbonate 
(50.2 g). The mixture was refluxed for 24 hours. The insoluble matter was 
filtered out, the filtrate was concentrated in vacuo, and chloroform (300 
ml) was added to the concentrate. This solution was washed with a 10% 
aqueous solution of sodium bicarbonate and a saturated sodium chloride 
solution, dried over anhydrous sodium sulfate, and concentrated in vacuo. 
The oily residue was purified by silica gel column chromatography to give 
13.5 g (46%) of the titled compound. 
IR (film, cm.sup.-1) 3383, 2941, 1516, 1464, 1262, 1236, 1142, 1029 
The following compound was prepared in the similar manner to Reference 
Example 1. 
N,N-Bis(2-hydroxyethyl)-3-(3,4-dimethoxyphenyl)propylamine (reference 
compound No. 1-2) 
IR (film, cm.sup.-1) 3386, 2941, 1515, 1463, 1261, 1156, 1029, 764 
Reference Example 2 
N,N-Bis(2-chloroethyl)-2-(3,4-dimethoxyphenyl)ethylamine hydrochloride 
(reference compound No. 2-1) 
##STR6## 
To a solution of N,N-bis(2-hydroxyethyl)-2-(3,4-dimethoxyphenyl)ethylamine 
(reference compound No. 1-1, 10.9 g) in chloroform (50 ml) was added 
thionyl chloride (14.4 g) dropwise under ice-cooling. The mixture was 
refluxed for 45 minutes. The reaction mixture was concentrated in vacuo, 
and isopropanol was added to the concentrate to give 10.2 g (74%) of the 
titled compound. 
mp 147.degree.-149.degree. C. 
IR (KBr, cm.sup.-1) 2326, 1520, 1466, 1268, 1238, 1159, 1140, 1028 
The following compound was prepared in the similar manner to Reference 
Example 2. 
N,N-Bis(2-chloroethyl)-3-(3,4-dimethoxyphenyl)propylamine hydrochloride 
(reference compound No. 2-2) 
mp 112.degree.-123.degree. C. (ethyl acetate-isopropyl ether) 
IR (KBr, cm.sup.-1) 2394, 1519, 1471, 1263, 1234, 1157, 1138, 1025 
Reference Example 3 
N,N-Bis(2-hydroxyethyl)-2-phenylethylamine (reference compound No. 3-1) 
##STR7## 
To a solution of 2-phenylethylbromide (20 g) in ethanol (100 ml) were added 
N,N-bis(2-hydroxyethyl)amine (90.8 g) and sodium iodide (21.6 g). The 
mixture was refluxed for 3 hours. The reaction mixture was concentrated in 
vacuo, saturated aqueous solution of sodium bicarbonate was added to the 
concentrate, and the whole was extracted with chloroform. The organic 
layer was washed with a saturated sodium chloride solution, dried over 
anhydrous magnesium sulfate, and concentrated in vacuo to give 17.5 g 
(77%) of the titled compound. 
IR (film, cm.sup.-1) 3382, 3026, 2947, 1495, 1455, 1047, 747, 700 
The following compounds were prepared in the similar manner to Reference 
Example 3. 
N,N-Bis(2-hydroxyethyl)-3-phenylpropylamine (reference compound No. 3-2) 
IR (film, cm.sup.-1) 3373, 2943, 1496, 1454, 1031, 749, 700 
N,N-Bis(2-hydroxyethyl)-4-phenylbutylamine (reference compound No. 3-3) 
IR (film, cm.sup.-1) 3377, 2936, 1496, 1454, 1041, 748, 700 
N,N-Bis(2-hydroxyethyl)-5-phenylpentylamine (reference compound No. 3-4) 
IR (film, cm.sup.-1) 3378, 2934, 1495, 1453, 1043, 747, 699 
Reference Example 4 
N,N-Bis(2-chloroethyl)-2-phenylethylamine hydrochloride (reference compound 
No. 4-1) 
##STR8## 
To a solution of N,N-bis(2-hydroxyethyl)-2-phenylethylamine (reference 
compound No. 3-1, 33.5 g) in chloroform (160 ml) was added thionyl 
chloride (57.1 g) dropwise under ice-cooling while stirring. The mixture 
was stirred at room temperature for 10 minutes, and refluxed for 1 hour. 
The reaction mixture was concentrated in vacuo, ethyl acetate and 
isopropyl ether were added to the concentrate, and the obtained crystals 
were collected by filtration to give 39.2 g (87%) of the titled compound. 
mp 116.degree.-117.degree. C. (ethyl acetate-isopropyl ether) 
IR (KBr, cm.sup.-1) 3008, 2423, 1498, 1479, 1456, 766, 746, 704 
The following compounds were prepared in the similar manner to Reference 
Example 4. 
N,N-Bis(2-chloroethyl)-3-phenylpropylamine hydrochloride (reference 
compound No. 4-2) 
mp 98.degree.-100 .degree. C. (ethyl acetate-isopropyl ether) 
IR (KBr, cm.sup.-1) 2965, 2360, 1484, 1458, 1325, 936, 753, 696 
N,N-Bis(2-chloroethyl)-4-phenylbutylamine hydrochloride (reference compound 
No. 4-3) 
mp 100.degree.-112.degree. C. (ethyl acetate-isopropyl ether) 
IR (KBr, cm.sup.-1) 2945, 2459, 1487, 1444, 1420, 926, 741, 698 
N,N-Bis(2-chloroethyl)-5-phenylpentylamine hydrochloride (reference 
compound No. 4-4) 
mp 69.degree.-75.degree. C. (ethyl acetate-isopropyl ether) 
IR (KBr, cm.sup.-1) 2937, 2859, 2459, 1454, 901, 742, 695 
EXAMPLES 
Example 1 
1-2-(3,4-Dimethoxyphenyl)ethyl!-4-(3-phenylpropyl)piperazine 
dihydrochloride (compound No. 1-1) 
##STR9## 
To a solution of N,N-bis(2-chloroethyl)-2-(3,4-dimethoxyphenyl)ethylamine 
hydrochloride (reference compound No. 2-1, 0.69 g) and 3-phenylpropylamine 
(0.41 g) in dimethylformamide (20 ml) were added potassium carbonate (0.83 
g) and sodium iodide (0.90 g). The mixture was stirred at 70.degree. C. 
for 2 hours. To the reaction mixture, water was added, and the whole was 
extracted with ethyl acetate. The organic layer was washed with water and 
a saturated sodium chloride solution, dried over anhydrous magnesium 
sulfate, and concentrated in vacuo. The oily residue was dissolved in 
ethanol, 6N hydrochloric acid (2 ml) was added thereto, and the solution 
was concentrated in vacuo to give 0.68 g (77%) of the titled compound 
(compound No. 1-1). 
mp 258.degree.-260.degree. C. (decomp.) 
IR (KBr, cm.sup.-1) 3977, 2355, 1518, 1265, 1140, 1028, 754, 704 
The following compounds were prepared in the similar manner to Example 1 
1-2-(3,4-Dimethoxyphenyl)ethyl!-4-(2-phenylethyl)piperazine 
dihydrochloride (compound No. 1-2) 
mp 268.degree.-272.degree. C. (decomp.) 
IR (KBr, cm.sup.-1) 3430, 2938, 2300, 1519, 1447, 1264, 1234, 1026 
1-2-(3,4-Dimethoxyphenyl)ethyl!-4-benzylpiperazine dihydrochloride 
(compound No. 1-3) 
mp 250.degree.-253.degree. C. (decomp.) 
IR (KBr, cm.sup.-1) 2978, 2360, 1520, 1467, 1267, 1236, 1149, 1027 
1-2-(3,4-Dimethoxyphenyl)ethyl!-4-(4-phenylbutyl)piperazine 
dihydrochloride (compound No. 1-4) 
mp over 280.degree. C. (ethanol) 
IR (KBr, cm.sup.-1) 2361, 1522, 1469, 1445, 1264, 1162, 1027, 696 
1-3-(3,4-Dimethoxyphenyl)propyl!-4-(2-phenylethyl)piperazine 
dihydrochloride (compound No. 1-5) 
mp 254.degree. C. (decomp., ethanol) 
IR (KBr, cm.sup.-1) 2360, 1518, 1455, 1236, 1139, 1028, 754, 703 
1-3-(3,4-Dimethoxyphenyl)propyl!-4-(3-phenylpropyl)piperazine 
dihydrochloride (compound No. 1-6) 
mp 254.degree.-257.degree. C. (decomp., methanol) 
IR (KBr, cm.sup.-1) 2984, 2394, 1515, 1452, 1258, 1235, 1155, 1029 
1-3-(3,4-Dimethoxyphenyl)propyl!-4-(4-phenylbutyl)piperazine 
dihydrochloride (compound No. 1-7) 
mp 256.degree.-259.degree. C. (decomp., ethanol) 
IR (KBr, cm.sup.-1) 2377, 1514, 1451, 1258, 1234, 1156, 1029, 699 
Example 2 
1-(3,4-Dimethoxybenzyl)-4-(2-phenylethyl)piperazine dihydrochloride 
(compound No. 2-1) 
##STR10## 
N,N-Bis(2-chloroethyl)-2-phenylethylamine hydrochloride (reference compound 
No. 4-1, 1.0 g), 3,4-dimethoxybenzylamine (1.2 g), potassium carbonate 
(1.5 g) and sodium iodide (1.1 g) were suspended in dimethylformamide (35 
ml). This suspension was stirred at 30.degree.-38.degree. C. for 2.5 
hours. To the reaction mixture, iced water was added, and the whole was 
extracted with ethyl acetate. The organic layer was washed with water and 
then with a saturated sodium chloride solution, dried over anhydrous 
sodium sulfate, and concentrated in vacuo. The oily residue was purified 
by silica gel column chromatography, and dissolved in methanol. To this 
methanol solution, conc. hydrochloric acid was added, and the precipitated 
crystals were collected by filtration to give 0.8 g (55%) of the titled 
compound. 
mp ca. 280.degree. C. (decomp.) 
IR (KBr, cm.sup.-1) 3447, 2980, 2335, 1590, 1520, 1449, 1265, 1245, 1159, 
1022, 949, 914, 760, 701, 650 
The following compounds were prepared in the similar manner to Example 2 
1-(3,4-Dimethoxybenzyl)-4-(3-phenylpropyl)piperazine dihydrochloride 
(compound No. 2-2) 
mp 257.degree.-260.degree. C. (decomp., ethanol) 
IR (KBr, cm.sup.-1) 2362, 1523, 1453, 1276, 1166, 1020, 750, 699 
1-2-(2,5-Dimethoxyphenyl)ethyl!-4-(3-phenylpropyl)piperazine 
dihydrochloride (compound No. 2-3) 
mp 240.degree. C. (decomp., ethanol) 
IR (KBr, cm.sup.-1) 2990, 2391, 1501, 1467, 1227, 1044, 959, 699 
1-(3,4-Dimethoxybenzyl)-4-(4-phenylbutyl)piperazine dihydrochloride 
(compound No. 2-4) 
mp 255.degree. C. (decomp., ethanol) 
IR (KBr, cm.sup.-1) 2945, 2338, 1519, 1445, 1267, 1164, 1023, 761 
1-2-(3,4-Dimethoxyphenyl)ethyl!-4-(5-phenylpentyl)piperazine 
dihydrochloride (compound No. 2-5) 
mp 260.degree.-268.degree. C. (decomp., ethanol) 
IR (KBr, cm.sup.-1) 2932, 2338, 1521, 1453, 1263, 1162, 1144, 700 
Formulation Examples 
Examples of the formulations of the compounds I! according to this 
invention are shown below. 
______________________________________ 
(Tablet) 
compound of this invention 
1 mg 
lactose 120 mg 
crystalline cellulose 38 mg 
low substituted hydroxypropylcellulose 
5 mg 
hydroxypropylcellulose-L 
5 mg 
magnesium stearate 1 mg 
total 170 mg 
compound of this invention 
5 mg 
lactose 175 mg 
crystalline cellulose 68 mg 
low substituted hydroxypropylcellulose 
10 mg 
hydroxypropylcellulose-L 
10 mg 
magnesium stearate 2 mg 
total 270 mg 
(Soft Capsule) 
compound of this invention 
50 mg 
vegetable oil 150 mg 
gelatin coat 140 mg 
total 340 mg 
(Injection) 
compound of this invention 
100 mg 
sodium chloride 0.9 g 
sodium hydroxide q.s. 
sterile purified water 
q.s. 
total 100 ml 
______________________________________ 
EFFECT OF THE INVENTION 
Pharmacological Test 
1. In order to study the utility of the compounds of this invention, 
experiments were performed to examine affinities for sigma receptors. 
1-1. Experiment Using 3H!(+)-SKF-10047 as a Labeled Ligand 
Affinities for sigma receptors were determined by the following method 
according to the report of Matsuno et al. (European Journal of 
Pharmacology, 231, 451-457 (1993)). (Experimental Method) 
A membrane preparation was prepared by the following method according to 
the paper of Tam et al. (Proc. Natl. Acad. Sci. USA, 80, 6703-6707 
(1983)). 
A brain of a Hartley guinea pig (weight: 300-400 g) was excised, the brain 
was homogenized in Tris-hydrochloric acid buffer (50 mM, pH 7.7, 
containing 0.32M sucrose) having a weight eight times that of the brain, 
and the homogenate was centrifuged to obtain a supernatant. The 
supernatant was ultracentrifuged for 20 minutes, the resulting pellet was 
suspended in Tris-hydrochloric acid buffer (50 mM, pH 7.7, the same buffer 
was used hereinafter), and the suspension was centrifuged again to obtain 
a membrane preparation. 
The specific binding of .sup.3 H!(+)-SKF-10047 was determined by the 
following method in advance. To the membrane preparation suspended in 
Tris-hydrochloric acid buffer was added .sup.3 H!(+)-SKF-10047 (5 nM) 
dissolved in Tris-hydrochloric acid buffer without adding a test compound, 
and they were allowed to react at 25.degree. C. for 30 minutes. Completing 
the reaction, the reaction mixture was filtered with suction through a 
glass filter, and radioactivity on the filter was measured with a liquid 
scintillation counter to determine total binding. In addition, to the 
membrane preparation was added a mixture of .sup.3 H!(+)-SKF-10047 (5 nM) 
and (+)-SKF-10047 (100 .mu.M) having no radioactivity without adding the 
test compound, and the binding with the membrane preparation was 
determined in the same manner as described above. The obtained binding was 
defined as the non-specific binding. The difference between the total 
binding and the non-specific binding obtained in this manner was defined 
as the specific binding. 
Secondly, the binding of the membrane preparation and .sup.3 
H!(+)-SKF-10047 was measured in the presence of the test compound while 
varying the concentration of the test compound to determine the 
concentration of the test compound in which the specific binding of 
.sup.3 H!(+)-SKF-10047 determined previously is inhibited by 50%, i.e., 
IC.sub.50. 
(Result) 
Results with compounds No. 1-1, 1-2 and 1-3 are shown in Table 1 as 
examples of the experimental results. 
TABLE 1 
______________________________________ 
IC.sub.50 (nM) 
______________________________________ 
compound No. 1-1 0.34 
compound No. 1-2 9.32 
compound No. 1-3 4.28 
______________________________________ 
As shown in Table 1, the compounds of this invention were recognized to 
inhibit the specific binding of .sup.3 H!(+)-SKF-10047 remarkably in the 
low concentration, and the compounds were found out to have high 
affinities for sigma receptors. 
1-2. Experiment Using .sup.3 H!(+)-PTZ as a Labeled Ligand 
Affinities for sigma receptors were determined by the following method 
using .sup.3 H!(+)-PTZ as a labeled ligand according to the report of 
DeHaven-Hudkins et al. (Eur. I. Pharmacol,, 227, 371-378 (1992)). 
(Experimental Method) 
A membrane preparation was prepared by the following method according to 
the paper of Tam et al. (Proc. Natl. Acad. Sci., USA, 80, 6703-6707 
(1983)). 
A brain of a Hartley guinea pig (weight: 300-400 g) was excised, the brain 
was homogenized in Tris-hydrochloric acid buffer (50 mM, pH 7.7, 
containing 0.32M sucrose) having a weight eight times that of the brain, 
and the homogenate was centrifuged to obtain a supernatant. The 
supernatant was ultracentrifuged for 20 minutes, the resulting pellet was 
suspended in Tris-hydrochloric acid buffer (50 mM, pH 7.7, the same buffer 
was used hereinafter), and the suspension was centrifuged again to obtain 
a membrane preparation. 
The specific binding of .sup.3 H!(+)-PTZ was determined by the following 
method in advance. To the membrane preparation suspended in 
Tris-hydrochloric acid buffer was added .sup.3 H!(+)-PTZ (5 nM) dissolved 
in Tris-hydrochloric acid buffer without adding a test compound, and they 
were allowed to react at 37.degree. C. for 150 minutes. Completing the 
reaction, the reaction mixture was filtered with suction through a glass 
filter, and radioactivity on the filter was measured with a liquid 
scintillation counter to determine total binding. In addition, to the 
membrane preparation was added a mixture of .sup.3 H!(+)-PTZ (5 nM) and 
(+)-PTZ (100 .mu.M) having no radioactivity without adding the test 
compound, and the binding with the membrane preparation was determined in 
the same manner as described above. The obtained binding was defined as 
the non-specific binding. The difference between the total binding and the 
non-specific binding obtained in this manner was defined as the specific 
binding. 
Secondly, the binding of the membrane preparation and .sup.3 H!(+)-PTZ was 
measured in the presence of the test compound while varying the 
concentration of the test compound to determine the concentration of the 
test compound in which the specific binding of .sup.3 H!(+)-PTZ 
determined previously is inhibited by 50%, i.e., IC.sub.50. 
(Result) 
Results with compounds No. 1-1, 1-2, 1-4 and 1-6 are shown in Table 2 as 
examples of the experimental results. The results are expressed in 
averages of 4-11 samples. 
TABLE 2 
______________________________________ 
IC.sub.50 (nM) 
______________________________________ 
compound No. 1-1 33.1 
compound No. 1-2 18.0 
compound No. 1-4 10.7 
compound No. 1-6 14.9 
______________________________________ 
As shown in Table 2, the compounds of this invention were recognized to 
inhibit the specific binding of .sup.3 H!(+)-PTZ remarkably in the low 
concentration and to have high affinities for sigma receptors, as well as 
in examining .sup.3 H!(+)-SKF-10047 as a labeled ligand. 
2. Experiment on the Increasing Effects on the Amount of Intracerebral 
Acetylcholine 
Since compounds increasing the amount of intracerebral acetylcholine were 
reported to be useful for therapeutic agents for dementia, etc. (The New 
England Journal of Medicine, 315, 1241-1245 (1986)), an experiment was 
performed to examine effects of the compounds of this invention on the 
amount of acetylcholine in rat brain. 
(Experimental Method) 
The amount of acetylcholine in rat brain was measured by the following 
method using intracerebral microdialysis method according to the report of 
Matsuno et al. (Brain Research, 575, 315-319 (1992)). 
A probe was inserted in a brain of a male Wistar rat (weight: 280-300 g), 
Ringer's solution containing 3 .mu.M eserine sulfate was perfused in the 
brain, acetylcholine recovered from the probe was determined by high-speed 
liquid chromatography. The amount of acetylcholine in rat brain was 
measured with time. When it became constant, the test compound suspended 
in 1% methylcellulose solution was administered orally to the rat, and the 
amount of intracerebral acetylcholine was measured. The amount of 
acetylcholine in rat brain (average of six samples) to which the test 
compound was not administered was used as a control. Table 3 shows the 
results expressed in percentages of amount of acetylcholine (averages of 
3-7 samples in 30 minutes after administration of the test compound) to 
the control. 
(Results) 
TABLE 3 
______________________________________ 
amount of 
amount of 
administration 
acetylcholine 
(mg/kg) (% control) 
______________________________________ 
compound No. 1-1 
10 154.3 
20 170.0 
compound No. 1-4 
40 146.2 
80 164.9 
compound No. 1-6 
20 146.1 
40 176.9 
______________________________________ 
As shown in Table 3, the compounds of this invention were recognized to 
have excellent effects to increase the amount of intracerebral 
acetylcholine. 
3. Experiment on Affinities for .mu. Receptors 
Affinities for .mu. receptors were determined by the following method 
according to the report of Nabeshima et al. (Eur. J. Pharmacol., 114, 
197-207 (1985)). As a .sup.3 H!-labeled ligand of .mu. receptors, .sup.3 
H!DAMGO whose high selectivity of .mu. receptors had been reported was 
used (Br. J. Pharmac., 77, 461-469, (1982)). 
(Experimental Method) 
A membrane preparation was prepared by the following method according to 
the report of Kosterlitz et al. (Br. J. Pharmac., 68, 333-342 (1980)). 
A brain of a male Wistar rat (weight: ca. 300 g) was excised, the brain was 
homogenized in Tris-hydrochloric acid buffer (50 mM, pH 7.7, the same 
buffer was used hereinafter) having a weight 20 times that of the brain, 
and the homogenate was ultracentrifuged for 15 minutes to obtain a pellet. 
This pellet was suspended in Tris-hydrochloric acid buffer, the suspension 
was incubated at 37.degree. C. for 30 minutes, ultracentrifuged for 15 
minutes, and the resulting pellet was used as a membrane preparation. 
The specific binding of .sup.3 H!DAMGO was determined by the following 
method in advance. To the membrane preparation suspended in 
Tris-hydrochloric acid buffer was added .sup.3 H!DAMGO (1 nM) dissolved 
in Tris-hydrochloric acid buffer without adding a test compound, and they 
were allowed to react at 25.degree. C. for 30 minutes. Completing the 
reaction, the reaction mixture was filtered with suction through a glass 
filter, and radioactivity on the filter was measured with a liquid 
scintillation counter to determine total binding. In addition, to the 
membrane preparation was added a mixture of .sup.3 H!DAMGO (1 nM) and 
naloxone (5 .mu.M) without adding the test compound, and the binding with 
the membrane preparation was determined in the same manner as described 
above. The binding was defined as the non-specific binding. The difference 
between the total binding and the non-specific binding obtained in this 
manner was defined as the specific binding. 
Secondly, the binding of the membrane preparation and .sup.3 H!DAMGO was 
measured in the presence of the test compound while varying the 
concentration of the test compound to determine the concentration of the 
test compound in which the specific binding of .sup.3 H!DAMGO determined 
previously is inhibited by 50%, i.e., IC.sub.50. 
(Result) 
Examples of the experimental results are shown below. Compounds No. 1-1, 
1-2 and 1-3 exhibit IC.sub.50 of higher than 10,000 nM, and the compounds 
of this invention were hardly recognized to inhibit the specific binding 
of .sup.3 H!DAMGO. From these results, it turned out that affinities of 
the compounds of this invention for .mu. receptors are very low and that 
the compounds hardly exhibit morphine-like effects. 
As apparent from the results of the above pharmacological tests, the 
compounds of this invention have high affinities for sigma receptors, 
hardly exhibit morphine-like effects, and have wide pharmaceutical uses 
for therapeutic agents for diseases in which sigma receptors are 
concerned, for example, cerebral neural function disorders such as 
dementia, depression, schizophrenia and anxiety neurosis, diseases 
accompanying abnormal immune response and cryptorrhea, digestive ulcer, 
etc. In addition, the compounds of this invention are particularly useful 
for therapeutic agents for cerebral neural function disorders coupled with 
increasing effects on the amount of intracerebral acetylcholine and 
improving effects on learning disorders caused by a cerebrovascular 
disorder. 
INDUSTRIAL POSSIBILITY OF UTILIZATION 
The compounds of this invention, that is, 1,4-(diphenylalkyl)piperazine 
derivatives have affinities for sigma receptors and are useful for 
therapeutic agents for cerebral neural function disorders such as 
dementia, depression, schizophrenia and anxiety neurosis, diseases 
accompanying abnormal immune response and cryptorrhea, digestive ulcer, 
etc.