1-Phenyl-1H-pyrazolo [3,4-b]pyrazine derivatives and process for preparing same

Novel 1-phenyl-1H-pyrazolo[3,4-b]pyrazine derivatives are provided which are represented by the formula: ##STR1## wherein A is (i) ##STR2## in which R.sub.1 and R.sub.2 are hydrogen or an alkyl, substituted alkyl, cycloalkyl, substituted cycloalkyl or amino group, or a divalent radical forming a nitrogen-containing saturated heterocyclic ring together with the nitrogen atom, (ii) ##STR3## wherein R.sub.3 is a phenyl group which is unsubstituted or substituted by halogen or a lower alkyl, lower alokoxy, carboxyl or nitro group, and R.sub.4 is halogen or a methyl or ethyl group, (iii)--OR.sub.5 in which R.sub.5 is a phenyl group which is unsubstituted or substituted by halogen or a hydroxyl, lower alkyl, lower alkoxy, amino or lower alkylamide group, or (iv)--OR.sub.6 is an alkyl group which is unsubstituted or substituted by halogen or a phenyl, furanyl, tetrahydrofuranyl or alkylamino group. These derivatives have antitumor or antiviral activity.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to a 1-phenyl-1H-pyrazolo[3,4-b]pyrazine 
derivative having excellent antitumor or antiviral activity, which is 
represented by the following formula (1): 
##STR4## 
In the above formula (1), A stands for (i) a group 
##STR5## 
in which R.sub.1 and R.sub.2 stand for a hydrogen atom, a univalent group 
selected from an alkyl group, a substituted alkyl group, a cycloalkyl 
group, a substituted cycloalkyl group and an amino group or a divalent 
group forming a substituted or unsubstituted, nitrogen-containing 
saturated heterocyclic ring together with the nitrogen atom: (ii) a group 
##STR6## 
in which R.sub.3 stands for a phenyl group or a substituted phenyl group 
in which at least one hydrogen atom is substituted by a halogen atom, a 
lower alkyl group, a lower alkoxy group, a carboxyl group or a nitro 
group, and R.sub.4 stands for a hydrogen atom, or a methyl or ethyl group; 
(iii) a group --OR.sub.5 in which R.sub.5 stands for a phenyl group or a 
substituted phenyl group in which at least one hydrogen atom is 
substituted by a halogen atom, a hydroxyl group, a lower alkyl group, a 
lower alkoxy group, an amino group or a lower alkylamide group; or (iv) a 
group --OR.sub.6 in which R.sub.6 stands for an alkyl group, a cycloalkyl 
group or a substituted alkyl group in which at least one hydrogen atom is 
substituted by a halogen atom, a substituted or unsubstituted phenyl 
group, a furanyl group, a tetrahydrofuranyl group or an alkylamino group. 
2. Description of the Prior Art 
Various substances having antitumor and antiviral activities have been 
developed and proposed. We made researches with a view to developing a 
compound having an antitumor or antiviral activity and capable of being 
used as an antitumor or antiviral agent, and as the result, we succeeded 
in synthesizing noval 1-phenyl-1H-pyrazolo[3,4-b]pyrazine derivatives 
represented by the above formula (1) and found that these compounds have 
excellent antitumor and antiviral activities and are useful as an 
antitumor or antiviral agent. 
SUMMARY OF THE INVENTION 
The novel compounds of the present invention, that is, 
1-phenyl-1H-pyrazol[3,4-b]pyrazine derivatives have a chemical structure 
represented by the following formula (1): 
##STR7## 
wherein A stands for a group 
##STR8## 
--OR.sub.5 or --OR.sub.6 and R.sub.1 through R.sub.6 are as defined above. 
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
When A in the formula (1) stands for a group 
##STR9## 
as the alkyl group constituting the groups R.sub.1 and R.sub.2, there can 
be mentioned, for example, linear alkyl groups having 1 to 10 carbon 
atoms, such as methyl, ethyl, propyl, butyl, pentyl, hexyl and decanyl 
groups, and branched alkyl groups having 1 to 10 carbon atoms, such as 
1-methylethyl, 2-methylpropyl, 1-methylpropyl, 1,1-dimethylethyl, 
2-methylbutyl, 3-methylbutyl, 1,1-dimethylpropyl, 2,2-dimethylpropyl, 
1-methylbutyl, 1-methylpentyl, 2-methylpentyl, 3-methylpentyl, 
4-methylpentyl, 1,3-dimethylbutyl, 1,2-dimethylbutyl, 2,3-dimethylbutyl, 
2,2-dimethylbutyl, 3,3-dimethylbutyl, 1-ethylbutyl, 2-ethylbutyl, 
1-methylhexyl and 1-methylheptyl groups. 
As the substituted alkyl group, there can be mentioned, for example, alkyl 
groups as exemplified above, in which at least one hydrogen atom is 
substituted by a hydroxyl group, a carboxyl group, a halogen atom, a lower 
alkylamino group, a phenyl group or a substituted phenyl group. As the 
halogen atom, there can be mentioned fluorine, chlorine and bromine, and 
as the alkyl group of the lower alkylamino group, there can be mentioned, 
for example, linear and branched alkyl groups having 1 to 6 carbon atoms, 
such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, pentyl, 
isopentyl, neopentyl and hexyl groups. The substituted phenyl group is a 
phenyl group in which at least one hydrogen atom is substituted by an 
appropriate substituent. As the substituent, there can be mentioned, for 
example, linear and branched lower alkyl groups having 1 to 6 carbon 
atoms, such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, pentyl, 
isopentyl, neopentyl and hexyl groups, halogen atoms such as fluorine, 
chlorine and bromine, a nitro group and a carboxyl group. 
As the cycloalkyl group, there can be mentioned cycloalkyl groups having 5 
to 8 carbon atoms, for example, cyclopentyl and cyclohexyl groups. 
As the nitrogen-containing sautrated heterocyclic ring, there can be 
mentioned, for example, pyrrolidinyl, imidazolidinyl, pyrazolidinyl, 
piperidinyl, piperazinyl and morpholinyl groups. 
These cycloalkyl and nitrogen-containing saturated heterocyclic groups may 
have at least one hydrogen atom thereof substituted by an appropriate 
substituent. As the substituent, there can be mentioned, for example, a 
hydroxyl group, linear and branched lower alkyl groups having 1 to 6 
carbon atoms, such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, 
pentyl, isopentyl, neopentyl and hexyl groups, halogen atoms such as 
fluorine, chlorine and bromine, and a nitro group and a carboxyl group. 
The groups R.sub.1 and R.sub.2 in A are preferably a hydrogen atom or a 
linear or branched alkyl group having 3 to 7 carbon atoms. 
When A in the formula (1) stands for a group 
##STR10## 
as the lower alkyl group constituting a substituent of the substituted 
phenyl group in R.sub.3, there can be mentioned, for example, linear and 
branched alkyl groups having 1 to 6 carbon atoms, such as methyl, ethyl, 
propyl, isopropyl, butyl, isobutyl, pentyl, isopentyl and neopentyl 
groups. As the lower alkoxy group constituting a substituent of the 
substituted phenyl group in R.sub.3, there can be mentioned, for example, 
linear and branched alkoxy groups having 1 to 6 carbon atoms, such as 
methoxy, ethoxy, propoxy, butoxy, pentyloxy and hexyloxy groups. 
The group R.sub.3 in A is preferably a phenyl group which is unsubstituted 
or substituted by a halogen atom or an alkyl group having 1 to 4 carbon 
atoms. 
When A in the formula (1) stands for a group --OR.sub.5, as the lower alkyl 
and lower alkoxy groups constituting substituents of the substituted 
phenyl group, there can be mentioned, for example, lower alkyl and lower 
alkoxy groups exemplified above with respect to R.sub.3. As the lower 
alkylamide group, there can be mentioned, for example, linear and branched 
alkylamide groups having 1 to 6 carbon atoms, such as acetamide, 
propionamide and butylamide groups. The group R.sub.5 is preferably a 
phenyl group which is unsubstituted or substituted by a halogen atom or an 
alkyl group having 1 to 4 carbon atoms. 
When A in the formula (1) stands for a group --OR.sub.6, as the alkyl, 
cycloalkyl and substituted alkyl groups, there can be mentioned, for 
example, alkyl, cycloalkyl and substituted alkyl groups exemplified above 
with respect to R.sub.1 and R.sub.2. The group R.sub.6 is preferably an 
alkyl group having 1 to 7 carbon atoms. 
The compound of the formula (1) in which A stands for a group 
##STR11## 
can be prepared by reacting 
5-substituted-1-phenyl-1H-pyrazolo[3,4-b]pyrazine of the formula (2) with 
the corresponding amine or nitrogen-containing heterocyclic ring compound 
as expressed by the following reaction formula (a): 
##STR12## 
wherein X stands for a halogen atom, a group --SO.sub.2 R (R is a lower 
slkyl group having 1 to 6 carbon atoms, a phenyl group, a methylphenyl 
group or an ethylphenyl group), a group --NO.sub.2 or a group --CN, and 
R.sub.1 and R.sub.2 are as defined above. 
The above-mentioned reaction (a) is carried out preferably at a temperature 
of 200.degree. to 250.degree. C. for 1 to 3 hours in a sealed tube which 
has been flushed with nitrogen, while an excessive amount of the amine or 
nitrogen-containing heterocyclic ring compound is used. 
A compound of the formula (2) in which X is a chlorine atom, that is, 
5-chloro-1-phenyl-1H-pyrazolo[3,4-b]pyrazine represented by the formula 
(2') given below, may be obtained, for example, according to the following 
reaction formula (b) by decarboxylation of 
5-amino-1-phenylpyrazole-4-carboxylic acid of the formula (3) by heating 
at, for example, 180.degree. C. to prepare 5-amino-1-phenylpyrazole of the 
formula (4), reaction of this compound with isoamyl nitrite in ethanol in 
the presence of dry hydrochloric acid to form 
5-amino-4-nitroso-1-phenylpyrazole hydrochloride of the formula (5), 
catalytic reduction of this hydrochloride with palladium-carbon to prepare 
4,5-diamino-1-phenylpyrazole of the formula (6), reaction of this compound 
with glyoxylic acid in water to prepare 
4,5-dihydro-1-phenyl-1H-pyrazole[3,4-b]pyrazin-5-one of the formula (7) 
and refluxing of this compound with phosphorus oxychloride: 
##STR13## 
A compound of the formula (1) in which A stands for a group 
##STR14## 
may be prepared by reacting 
5-substituted-1-phenyl-1H-pyrazolo[3,4-b]pyrazine with a substituted or 
unsubstituted phenylamine according to the following reaction formula 
(a'): 
##STR15## 
wherein X stands for a halogen atom, a group --SO.sub.2 R (R stands for a 
lower alkyl group having 1 to 6 carbon atoms, a phenyl group, a 
methylphenyl group, or an ethylphenyl group), a group --NO.sub.2 or a 
group --CN, and R.sub.3 and R.sub.4 are as defined above. 
The above-mentioned reaction (a') is carried out preferably at a 
temperature of 200.degree. to 250.degree. C. for 1 to 3 hours in a sealed 
tube which has been flushed with nitrogen, while an excessive amount of 
the phenylamine is used. 
A compound of the formula (1) in which A is a group --OR.sub.5 may be 
prepared by reacting a 5-substituted-1-phenyl-1H-pyrozolo[3,4b]pyrazine of 
the formula (2) with the corresponding phenol derivative according to the 
following reaction formula (a"): 
##STR16## 
wherein X stands for a halogen atom, a group --SO.sub.2 --R' (R' stands 
for an alkyl group having 1 to 6 carbon atoms, a phenyl group, a 
methylphenyl group or an ethylphenyl group), a group --NO.sub.2 or a group 
--CN, M is an alkali metal such as Na or K, and R.sub.5 is as defined 
above. 
The above-mentioned reaction (a") is carried out preferably at a 
temperature of 100.degree. to 150.degree. C. for 1 to 3 hours in 
dimethylsulfoxide or an alcohol while an excessive amount of the 
alcoholate R.sub.5 --OM is used. 
A compound of the formula (1) in which A is a group --OR.sub.6 may be 
prepared by reacting a 5-substituted-1-phenyl-1H-pyrazolo[3,4-b]pyrazine 
of the formula (2) with the corresponding alcoholate according to the 
following reaction formula (a""): 
##STR17## 
wherein X stands for a halogen atom, a group --SO.sub.2 --R'(R' stands for 
an alkyl group having 1 to 6 carbon atoms, a phenyl group, a methylphenyl 
group or an ethylphenyl group), a group --NO.sub.2 or a group --CN, M is 
an alkali metal such as Na or K and R.sub.6 is the same as defined above. 
The above-mentioned reaction (a"') may preferably be carried out under 
conditions similar to those which are described hereinbefore with respect 
to the reaction (a"). 
Specific examples of the compound of the present invention represented by 
the above-mentioned formula (1) will now be described. 
__________________________________________________________________________ 
##STR18## 
Com- Exam- 
pound ple 
No. R.sub.1 R.sub.2 
Name of Compound 
No. 
__________________________________________________________________________ 
1 C.sub.3 H.sub.7 
H 5-propylamino-1-phenyl-1H 
1 
pyrazolo[3,4-b]pyrazine 
2 C.sub.4 H.sub.9 
H 5-butylamino-1-phenyl-1H 
2 
pyrazolo[3,4-b]pyrazine 
3 C.sub.5 H.sub.11 
H 5-pentylamino-1-phenyl-1H 
3 
pyrazolo[3,4-b]pyrazine 
3 
4 C.sub.6 H.sub.13 
H 5-hexylamino-1-phenyl-1H 
4 
pyrazolo[3,4-b]pyrazine 
5 C.sub.10 H.sub.21 
H 5-decanylamino-1-phenyl-1H 
5 
pyrazolo[3,4-b]pyrazine 
6 HOC.sub.2 H.sub.4 
H 5-(2-hydroxyethylamino)-1- 
6 
phenyl-1Hpyrazolo[3,4-b]- 
pyrazine 
7 
##STR19## H 5-(2-hydroxypropylamino)-1- phenyl-1Hpyrazolo[3,4-b] 
- pyrazine 7 
8 
##STR20## H 5-(1-methylpropylamino)-1- phenyl-1Hpyrazolo[3,4-b] 
- pyrazine 8 
9 
##STR21## H 5-(2-ethylhexylamino)-1- phenyl-1Hpyrazolo[3,4-b]- 
pyrazine 9 
10 
HOOC(CH.sub.2).sub.3 
H 5-(3-carboxypropylamino)-1- 
10 
phenyl-1Hpyrazolo[3,4-b]- 
pyrazine 
11 HOOC(CH.sub.2).sub.5 
H 5-(5-carboxypentylamino)-1- 
11 
phenyl-1Hpyrazolo[3,4-b]- 
pyrazine 
12 Cl(CH.sub.2).sub.2 
H 5-(2-chloroethylamino)-1- 
12 
phenyl-1Hpyrazolo[3,4-b]- 
pyrazine 
13 
##STR22## H 5-(2-N,Ndimethylamino- ethylamino)-1-phenyl-1H 
pyrazolo[3,4-b]pyrazine 
13 
14 
##STR23## H 5-benzylamino-1-phenyl-1H pyrazolo[3,4-b]pyrazine 
14 
15 
##STR24## H 5-(4-nitrobenzylamino)-1- phenyl-1Hpyrazolo[3,4-b]- 
yrazine 15 
16 
##STR25## H 5-(4-chlorobenzylamino)-1- phenyl-1Hpyrazolo[3,4-b]- 
pyrazine 16 
17 
##STR26## H 5-(3-methylbenzylamino)-1- phenyl-1Hpyrazolo[3,4-b]- 
pyrazine 17 
18 
C.sub.4 H.sub.9 
C.sub.4 H.sub.9 
5-dibutylamino-1-phenyl-1H 
18 
pyrazolo[3,4-b]pyrazine 
19 HO(CH.sub.2).sub.2 
CH.sub.3 
5-(2-hydroxymethylamino)-1- 
19 
phenyl-1Hpyrazolo[3,4-b]- 
pyrazine 
20 
##STR27## CH.sub.3 
5-benzylmethylamino-1-phenyl- 1Hpyrazolo[3,4-b]pyraz 
ine 20 
21 
##STR28## H 5-cyclopentylamino-1-phenyl- 1Hpyrazolo 8 
3,4-b]pyrazine 21 
22 
##STR29## H 5-cyclohexylamino-1-phenyl- 1Hpyrazolo[3,4-b]pyrazin 
e 22 
23 
##STR30## H 5-(4-methylcyclohexylamino)-1- phenyl-1Hpyrazolo[3,4 
-b]- pyrazine 23 
24 
NH.sub.2 H 5-hydrazino-1-phenyl-1H 
24 
pyrazolo[3,4-b]pyrazine 
25 
##STR31## 5-piperidino-1-phenyl-1H pyrazolo[3,4-b]pyrazine 
25 
26 
##STR32## 5-(3-carboxypiperidion)-1-phenyl- 1Hpyrazolo[3,4-b]p 
yrazine 26 
27 
##STR33## 5-morpholino-1-phenyl-1H pyrazolo[3,4-b]pyrazine 
27 
__________________________________________________________________________ 
__________________________________________________________________________ 
##STR34## 
Compound Example 
No. R.sub.3 R.sub.4 
Name of Compound 
No. 
__________________________________________________________________________ 
28 
##STR35## H 5-anilino-1-phenyl-1Hpyraz- olo[3,4-b]pyrazine 
28 
29 
##STR36## CH.sub.3 
5-Nmethylanilino-1-phenyl- 1Hpyrazolo[3,4-b]pyrazine 
29 
30 
##STR37## H 5-(2-toluidino)-1-phenyl- 1Hpyrazolo[3,4-b]pyrazine 
30 
31 
##STR38## H 5-(3-toluidino)-1-phenyl- 1Hpyrazolo[3,4-b]pyrazine 
31 
32 
##STR39## H 5-(4-toluidino)-1-phenyl- 1Hpyrazolo[3,4-b]pyrazine 
-- 
33 
##STR40## H 5-(2-anisidino)-1-phenyl- 1Hpyrazolo[3,4-b]pyrazine 
34 
34 
##STR41## H 5-(3-anisidino)-1-phenyl 1Hpyrazolo[3,4-b]pyrazine 
-- 
35 
##STR42## H 5-(4-anisidino)-1-phenyl- 1Hpyrazolo[3,4-b]pyrazine 
-- 
36 
##STR43## H 5-(2-phenetidino)-1-phenyl- 1Hpyrazolo 
[3,4-b]pyrazine -- 
37 
##STR44## H 5-(3-phenetidino)-1-phenyl- 1Hpyrazolo[3,4-b]pyrazin 
e -- 
38 
##STR45## H 5-(4-phenetidino)-1-phenyl- 1Hpyrazolo[3,4-b]pyrazin 
e 35 
39 
##STR46## H 5-(2-chloroanilino)-1-phenyl- 1Hpyrazolo[3,4-b]pyraz 
ine -- 
40 
##STR47## H 5-(3-chloroanilino)-1-phenyl- 1Hpyrazolo[3,4-b]pyraz 
ine -- 
41 
##STR48## H 5-(4-chloroanilino)-1-phenyl- 1Hpyrazolo[3,4-b]pyraz 
ine 36 
42 
##STR49## H 5-(2-fluoroanilino)-1-phenyl- 1Hpyrazolo[3,4-b]pyraz 
ine -- 
43 
##STR50## H 5-(3-fluoroanilino)-1-phenyl- 1Hpyrazolo[3,4-b]pyraz 
ine -- 
44 
##STR51## H 5-(4-fluoroanilino)-1-phenyl- 1Hpyrazolo[3,4-b]pyraz 
ine 37 
45 
##STR52## H 5-(2-bromoanilino)-1-phenyl- 1Hpyrazolo[3,4-b]pyrazi 
ne -- 
46 
##STR53## H 5-(3-bromoanilino)-1-phenyl- 1Hpyrazolo[ 
3,4-b]pyrazine -- 
47 
##STR54## H 5-(4-bromoanilino)-1-phenyl- 1Hpyrazolo[3,4-b]pyrazi 
ne -- 
48 
##STR55## H 5-(2-nitroanilino)-1-phenyl- 1Hpyrazolo[3,4-b]pyrazi 
ne -- 
49 
##STR56## H 5-(3-nitroanilino)-1-phenyl- 1Hpyrazolo[ 
3,4-b]pyrazine 38 
50 
##STR57## H 5-(4-nitroanilino)-1-phenyl- 1Hpyrazolo[3,4-b]pyrazi 
ne -- 
51 
##STR58## H 5-(2-ethylanilino)-1-phenyl- 1Hpytrazolo[3,4-b]pyraz 
ine -- 
52 
##STR59## H 5-(3-ethylanilino)-1-phenyl- 1Hpyrazolo[3,4-b]pyrazi 
ne -- 
53 
##STR60## H 5-(4-ethylanilino)-1-phenyl- 1Hpyrazolo[3,4-b]pyrazi 
ne -- 
54 
##STR61## H 5-(2-propylanilino)-1-phenyl- 1Hpyrazolo[3,4-b]pyraz 
ine -- 
55 
##STR62## H 5-(3-propylanilino)-1-phenyl- 1Hpyrazolo[3,4-b]pyraz 
ine -- 
56 
##STR63## H 5-(4-propylanilino)-1-phenyl- 1Hpyrazolo[3,4-b]pyraz 
ine -- 
57 
##STR64## H 5-(2-butylanilino)-1-phenyl- 1Hpyrazolo[3,4-b]pyrazi 
ne ' 
58 
##STR65## H 5-(3-butylanilino)-1-phenyl- 1Hpyrazolo[ 
3,4-b]pyrazine 33 
59 
##STR66## H 5-(4-butylanilino)-1-phenyl- 1Hpyrazolo[3,4-b]pyrazi 
ne -- 
60 
##STR67## H 5-(2-carboxyanilino)-1-phenyl- 1Hpyrazolo[3,4-b]pyra 
zine -- 
61 
##STR68## H 5-(3-carboxyanilino)-1-phenyl- 1Hpyrazolo[3,4-b]pyra 
zine -- 
62 
##STR69## H 5-(4-carboxyanilino)-1-phenyl- 1Hpyrazolo[3,4-b]pyra 
zine -- 
63 
##STR70## H 5-(2,3-dimethylanilino)-1- phenyl-1Hpyrazolo[3,4-b]- 
pyrazine 33 
64 
##STR71## H 5-(2,4-dimethylanilino)-1- phenyl-1Hpyrazolo[3,4-b]- 
pyrazine -- 
65 
##STR72## H 5-(2,5-dimethylanilino)-1- phenyl-1Hpyrazolo[3,4-b]- 
pyrazine -- 
66 
##STR73## H 5-(2,6-dimethylanilino)-1- phenyl-1Hpyrazolo[3,4-b]- 
pyrazine -- 
67 
##STR74## H 5-(3,4-dimethylanilino)-1- phenyl-1Hpyrazolo[3,4-b]- 
pyrazine -- 
68 
##STR75## H 5-(3,5-dimethylanilino)-1- phenyl-1Hpyrazolo[3,4-b]- 
pyrazine -- 
__________________________________________________________________________ 
__________________________________________________________________________ 
(3) A = OR.sub.5 
Compound Example 
No. R.sub.5 Name of Compound No. 
__________________________________________________________________________ 
69 
##STR76## 5-phenoxy-1-phenyl-1Hpyrazolo- [3,4-b]pyrazine 
39 
70 
##STR77## 5-(4-methylphenoxy)-1-phenyl- 1Hpyrazolo[3,4-b]pyraz 
ine 40 
71 
##STR78## 5-(4-isopropylphenoxy)-1-phenyl- 1Hpyrazolo[3,4-b]pyr 
azine 41 
72 
##STR79## 5-(3-aminophenoxy)-1-phenyl- 1Hpyrazolo[3,4-b]pyrazi 
ne 42 
73 
##STR80## 5-(4-acetoamidophenoxy)-1-phenyl- 1Hpyrazolo[3,4-b]py 
razine 43 
74 
##STR81## 5-(2-methoxyphenoxy)-1-phenyl- 1Hpyrazolo[3,4-b]pyraz 
ine 44 
75 
##STR82## 5-(4-methoxyphenoxy)-1-phenyl- 1Hpyrazolo[3,4-b]pyraz 
ine 45 
76 
##STR83## 5-(4-ethoxyphenoxy)-1-phenyl- 1Hpyrazolo[3,4-b]pyrazi 
ne 46 
77 
##STR84## 5-(4-hydroxyphenoxy)-1-phenyl- 1Hpyrazolo[3,4-b]pyraz 
ine 47 
78 
##STR85## 5-(4-chlorophenoxy)-1-phenyl- 1Hpyrazolo[3,4-b]pyrazi 
ne 48 
79 
##STR86## 5-(4-bromophenoxy)-1-phenyl- 1Hpyrazolo[3,4-b]pyrazin 
e 49 
__________________________________________________________________________ 
______________________________________ 
(4) A = OR.sub.6 
Com- Exam- 
pound ple 
No. R.sub.6 Name of Compound 
No. 
______________________________________ 
80 CH.sub.3 5-methoxy-1-phenyl- 
50 
1Hpyrazolo- 
[3,4-b]pyrazine 
81 C.sub.2 H.sub.5 5-ethoxy-1-phenyl- 
51 
1Hpyrazolo- 
[3,4-b]pyrazine 
82 C.sub.3 H.sub.7 5-propoxy-1-phenyl- 
52 
1Hpyrazolo- 
[3,4-b]pyrazine 
83 isoC.sub.3 H.sub.7 
5-isopropoxy-1- 
53 
phenyl-1Hpyraz- 
olo[3,4-b] pyrazine 
84 C.sub.4 H.sub.9 5-butoxy-1-phenyl- 
54 
1Hpyrazolo- 
[3,4-b]pyrazine 
85 isoC.sub.4 H.sub.9 
5-isobutoxy-1- 
55 
phenyl-1Hpyraz- 
olo[3,4-b] pyrazine 
86 secC.sub.4 H.sub.9 
5-sec-butoxy-1- 
56 
phenyl-1Hpyraz- 
olo[3,4-b] pyrazine 
87 C.sub.5 H.sub.11 5-pentyloxy-1- 
57 
phenyl-1Hpyraz- 
olo[3,4-b] pyrazine 
88 isoC.sub.5 H.sub.11 
5-isopentyloxy-1- 
58 
phenyl-1Hpyraz- 
olo[3,4-b] pyrazine 
89 C.sub.6 H.sub.13 5-hexyloxy-1- 59 
phenyl-1Hpyraz- 
olo[3,4-b] pyrazine 
90 2-C.sub.6 H.sub.13 
5-(2-hexyloxy)-1- 
60 
[(C.sub.4 H.sub.9)(CH.sub.3)CH] 
phenyl-1Hpyraz- 
olo[3,4-b]pyrazine 
91 C.sub.8 H.sub.17 5-octyloxy-1-phenyl- 
61 
1Hpyrazolo[3,4- 
b]pyrazine 
92 C.sub.6 H.sub.5CH.sub.2 
5-benzyloxy-1- 
62 
phenyl-1Hpyraz- 
olo[3,4-b] pyrazine 
93 
##STR87## 5-cyclohexyloxy-1- phenyl-1Hpyraz- olo[3,4-b] 
pyrazine 63 
94 C.sub.3 H.sub.7CHCHCH.sub.2 
5-(trans-2-hexenyl- 
64 
(trans) oxy)-1-phenyl- 
1Hpyrazolo[3,4- 
b]pyrazine 
95 (CH.sub.3).sub.2 NCH.sub.2CH.sub.2 
5-(2-dimethylamino- 
65 
ethoxy)-1-phenyl- 
1Hpyrazolo[3,4- 
b]pyrazine 
96 
##STR88## 5-(2-tetrahydro- furfuryloxy)-1- phenyl-1Hpyraz- 
olo[3,4-b] pyrazine 
66 
97 
##STR89## 5-(2-furfuryloxy)-1- phenyl-1Hpyraz- olo[3,4-b] 
pyrazine 67 
______________________________________ 
The compounds represented by the above formula (1) have excellent antitumor 
and/or antiviral activities and inhibit propagation of cancerous cells and 
virus. Accordingly, the compounds are useful as an antitumor or antiviral 
agent.