Synthesis of some novel 5-substituted benzamido-6-arylamino-pyrazolo[3,4-D]pyrimidin-4-one derivatives for herbicidal activity

Article abstract of DOI:10.1080/10426507.2019.1633529

Sixteen novel 3-methylthio-5-substituted benzamido-6-arylamino-1-phenyl-1H-pyrazolo[3,4-d]pyrimidin-4 (5H)-one derivatives (4a–p) were successfully synthesized from iminophosphoranes, aryl isocyanate, and substituted benzoylhydrazine. The structures of the title compounds were elucidated by FT-IR, ¹H NMR, ¹³C NMR, and HRMS. Herbicidal activity of the compounds 4a–p against Brassica napus (rape), Echinochloa crusgalli (barnyard grass), Cucumis sativus (cucumber), and Triticum aestivum (wheat) were determined. The results showed that 5-(2-chlorobenzamido)-6-phenylamino-3-methylthio-1-phenyl-1H-pyrazolo[3,4-d]pyrimidin-4 (5H)-one (4c) displayed remarkable inhibition activity against the stalk and root of rape with 100% inhibition rate at the dosages of 10 mg/L and 100 mg/L, and 5-(4-nitrobenzamido)-6-phenylamino-3-methylthio-1-phenyl-1H-pyrazolo[3,4-d]pyrimidin-4 (5H) -one (4d) exhibited excellent activity against the stalk and root of barnyard grass with 100% inhibition rate at the same dosages.

Full text of DOI:10.1080/10426507.2019.1633529

Phosphorus, Sulfur, and Silicon and the Related Elements
ISSN: 1042-6507 (Print) 1563-5325 (Online) Journal homepage: https://www.tandfonline.com/loi/gpss20
Synthesis of some novel 5-substituted
benzamido-6-arylamino-
pyrazolo[3,4-D]pyrimidin-4-one derivatives for
herbicidal activity
Jin Luo, Shu Li, Qiongwen Kang, Yi Sun & Tao Wang
To cite this article: Jin Luo, Shu Li, Qiongwen Kang, Yi Sun & Tao Wang (2019): Synthesis of
some novel 5-substituted benzamido-6-arylamino-pyrazolo[3,4-D]pyrimidin-4-one derivatives
for herbicidal activity, Phosphorus, Sulfur, and Silicon and the Related Elements, DOI:
10.1080/10426507.2019.1633529
To link to this article: https://doi.org/10.1080/10426507.2019.1633529
View supplementary material
Published online: 27 Jun 2019.
Submit your article to this journal
Article views: 8
View Crossmark data
Full Terms & Conditions of access and use can be found at
https://www.tandfonline.com/action/journalInformation?journalCode=gpss20

PHOSPHORUS, SULFUR, AND SILICON AND THE RELATED ELEMENTS
https://doi.org/10.1080/10426507.2019.1633529
Synthesis of some novel 5-substituted benzamido-6-arylamino-pyrazolo
[3,4-D]pyrimidin-4-one derivatives for herbicidal activity
Jin Luoa, Shu Lib, Qiongwen Kangb, Yi Sunb, and Tao Wangb
b
aAnalytical & Testing Center, Jiangxi Normal University, Nanchang, Jiangxi, China; Jiangxi Province Key Laboratory of Chemical Biology,
College of Chemistry and Chemical Engineering, Jiangxi Normal University, Nanchang, Jiangxi, China
ABSTRACT
ARTICLE HISTORY
Received 9 January 2019
Accepted 15 June 2019
Sixteen novel 3-methylthio-5-substituted benzamido-6-arylamino-1-phenyl-1H-pyrazolo[3,4-d]pyri-
midin-4 (5H)-one derivatives (4a–p) were successfully synthesized from iminophosphoranes, aryl
isocyanate, and substituted benzoylhydrazine. The structures of the title compounds were eluci-
1
dated by FT-IR, H NMR, 13C NMR, and HRMS. Herbicidal activity of the compounds 4a–p against
KEYWORDS
Pyrazolo[3,4-d]pyrimidin-4
(5H)-one derivatives;
synthesis; herbicidal activity;
inhibition rate
Brassica napus (rape), Echinochloa crusgalli (barnyard grass), Cucumis sativus (cucumber), and
Triticum aestivum (wheat) were determined. The results showed that 5-(2-chlorobenzamido)-6-phe-
nylamino-3-methylthio-1-phenyl-1H-pyrazolo[3,4-d]pyrimidin-4 (5H)-one (4c) displayed remarkable
inhibition activity against the stalk and root of rape with 100% inhibition rate at the dosages of
10 mg/L and 100mg/L, and 5-(4-nitrobenzamido)-6-phenylamino-3-methylthio-1-phenyl-1H-pyra-
zolo[3,4-d]pyrimidin-4 (5H) -one (4d) exhibited excellent activity against the stalk and root of barn-
yard grass with 100% inhibition rate at the same dosages.
GRAPHICAL ABSTRACT
Introduction
iminophosphoranes can not only synthesize many known N-
heterocyclic compounds with biological activity, but also pre-
pare some new heterocyclic systems.[19] Recently, we have
become interested in the synthesis of new bioactive fuze hetero-
cycles, such as pyrazolo[3,4-d]pyrimidine-4-ones from various
iminophosphoranes, with the aim of evaluating their biological
activities. Continuing our ongoing program on the synthesis of
herbicidal compounds,[20] and inspired by the excellent herbici-
dal properties of pyrazolo[3,4-d]pyrimidine-4-ones,[21] in the
present study a new series of pyrazolo[3,4-d]pyrimidin-4-one
compounds 4 has been synthesized from iminophosphoranes,
aryl isocyanate, and substituted benzoylhydrazine via tandem
aza-Wittig and annulation reactions. The subsequent herbicidal
testing indicated that many target compounds showed good
herbicidal activity against the root and stalk of Brassica napus
(rape), Echinochloa crusgalli (barnyard grass), Cucumis sativus
Heterocyclic compounds with flexible structures, high-activ-
ities, and low- toxicity conform to requirements of the develop-
ment of pesticide. The study of heterocyclic compounds
inclines to complicated structural fused heterocyclic, bis-het-
erocyclic, multi-heterocyclic compounds.[1] Pyrazolo[3,4-d]pyr-
imidine, which represent a class of heterocyclic compound, is
extensively used heterocyclic system in drug discovery and
development. Pyrazolo[3,4-d]pyrimidine derivatives have
received widespread attention due to their structural similarity
with purine nucleus, and some of these derivatives exhibit
remarkable biological activities such as antiviral,[2] antimicro-
bial,[3] anti-inflammatory,[4] antimicrobial,[5] antitubercular,[6]
antifungal,[7] anticancer,[8,9] and herbicidal activity.[10]
Over the past thirty years, the aza-Wittig reactions of imino-
phosphoranes are an effective method for the synthesis of N-
heterocyclic compounds.[11–18] The aza-Wittig reactions of (cucumber), and Triticum aestivum (wheat).
CONTACT Jin Luo
Jiangxi Province Key Laboratory of Chemical Biology, College of Chemistry and Chemical Engineering, Jiangxi Normal University, Nanchang, Jiangxi,
330022, China.
jinluo@jxnu.edu.cn
Analytical & Testing Center, Jiangxi Normal University, Nanchang, Jiangxi, 330022, China; Tao Wang
wangtao@jxnu.edu.cn
Color versions of one or more of the figures in the article can be found online at www.tandfonline.com/gpss.
Supplemental data for this article is available online at https://doi.org/10.1080/10426507.2019.1633529.
ß 2019 Taylor & Francis Group, LLC

2
J. LUO ET AL.
Scheme 1. The synthetic route of the compound 4.
compounds. The obtained data illustrated that many of these
compounds exhibited excellent herbicidal activity. For
example, compounds 4c, 4d, 4e, 4f, 4g, 4l, 4m, and 4p
showed 100% inhibition rate to root and stalk of rape at
Results and discussion
Chemistry
Scheme 1 demonstrates the synthetic procedures of the inter-
mediate and target compounds. Accordingly, the starting 100 mg/L. Compounds 4d, 4m, and 4p displayed 100%
material 5-amino-3-methylthio-1-phenyl-1H-pyrazole-4-car-
boxylic acid ethyl ester 1 reacted with triphenylphosphine,
hexachloroethane, and Et3N in anhydrous acetonitrile to fur-
nish iminophosphorane 2. Iminophosphorane 2 treated with
arylisocyanate in dry methylene chloride under nitrogen to
give carbodiimides 3. Then, the direct reaction of intermediate
3 and various benzoylhydrazine in the presence of a catalytic
of sodium ethoxide at room temperature provided pyra-
zolo[3,4-d]pyrimidin-4-one compounds 4 (Figure 1).
inhibition rate to root and stalk of barnyard grass at
100 mg/L. Compounds 4d, 4g, 4m, and 4p indicated 100%
inhibition rate to root and stalk of cucumber at 100 mg/L.
Compounds 4d, 4f, 4g, 4i, 4l, 4m, and 4p demonstrated
100% inhibition rate to root and stalk of wheat at 100 mg/L.
Compound 4k exhibited 100% inhibition rate to root and
stalk of rape, barnyard grass, cucumber, and wheat at
10 mg/L. Comparing herbicidal activities among the title
compounds in Table 1, it was found that the Ar1 and Ar2
groups have notable impact on the herbicidal activity. The
title compounds with 4-Cl and NO2 as Ar1 and Ar2 (4d,
4m, and 4p) showed higher inhibitory rate (100%) against
the root and stalk of the tested plants at 100 mg/L.
All the compounds 4 were purified by recrystallization
and characterized by FT-IR, 1H NMR, 13C NMR, and
1
HRMS. The H NMR spectra revealed that the single peak
at about 2.6 ppm and 2.4 ppm were attributed to the methyl
of SCH3 and Ph-CH3, respectively. The single peak at about
11.1 ppm and 9.8 ppm belonged to NH. In 13C NMR, the
carbon of SCH3 appeared at 13.1 ppm, and the carbon of
Ph-CH3 appeared at 21.6 ppm. The characteristic carbon sig-
nal at about 167 ppm corresponded to the carbonyl group
(C ¼ O). In addition, the high-resolution mass spectra
(HRMS) agreed with the calculated molecular weights of the
title compounds 4.
Conclusions
In conclusion, various substituted pyrazolo[3,4-d]pyrimidine-
4-one compounds 4a–p were synthesized and confirmed by
1H NMR, 13C NMR, FT-IR, and HRMS. The herbicidal activ-
ity of the title compounds against the root and stalk of rape,
cucumber, wheat, and barnyard grass was investigated. Some
of the tested compounds revealed good herbicidal activity, in
particular 5-(2-chlorobenzamido)-6-phenylamino-3-methyl-
thio-1-phenyl-1H-pyrazolo[3,4-d]pyrimidin-4 (5H)-one (4c)
and 5-(4-nitro benzamido)-6-phenylamino-3-methylthio-1-
phenyl-1H-pyrazolo[3,4-d]-pyrimidin-4 (5H)-one (4d). The
studies of the novel pyrazolo[3,4-d]pyrimidine-4-one com-
pounds with high herbicidal activity will provide useful infor-
Herbicidal activity
The newly synthesized compounds 4a–p were evaluated for
their herbicidal activity against Brassica napus (rape),
Echinochloa crusgalli (barnyard grass), Cucumis sativus
(cucumber), and Triticum aestivum (wheat) at the dosages
of 100 mg/L and 10 mg/L according to the literature proced-
ure.[21] Table
1 shows the inhibition rates of these mation for the design and discovery of fuze heterocycles.

PHOSPHORUS, SULFUR, AND SILICON AND THE RELATED ELEMENTS
3
Figure 1. Structures of products 4a–p.
Iminophosphorane 2 was synthesized as reported.[21] The
Experimental
1
Supplemental Materials contains sample H and 13C NMR
An electrothermal melting-point apparatus was used to record
melting points. Infrared (IR) spectra were collected with a
spectra of the products 4 (Figures S1–S32).
NicoQt 6700 spectrometer in KBr pellets. H and 13C NMR
1
were recorded on Bruker 400 spectrometer with DMSO as the
solvent at 400 MHz (1H) and 100 MHz (13C). High resolution
mass spectra (HRMS) were acquired on a micro-TOF II
Instrument. All the chemicals used were of AR grade.
Methylene chloride, acetonitrile, and triethylamine were dried
Synthesis of 5-substituted benzamido-6-arylamino-3-
methylthio-1-phenyl-1H-pyrazolo[3,4-d]pyrimidin-4 (5H)-
one 4 (general procedure)
Iminophosphorane 2 (2 mmol) was dissolved in dry methy-
and distilled according to standard procedures. lene chloride (25 mL) and arylisocyanate (2 mmol) was added

4
J. LUO ET AL.
Table 1. The inhibition percentage (%) of compounds 4a–p to barnyard grass, rape, cucumber, and wheat.
Rape
Barnyard grass
Stalk
Root
Stalk
Root
Compd.
Ar1
Ar2
10 mg/L
100 mg/L
10 mg/L
100 mg/L
10 mg/L
100 mg/L
10 mg/L
100 mg/L
4a
4b
4c
4d
4e
4f
4g
4h
4i
4j
4k
4l
4m
4n
4o
4p
2,4-D
Ph
Ph
Ph
Ph
Ph
17
ꢂ6
ꢂ40
100
100
100
100
100
ꢂ35
60
ꢂ48
ꢂ37
100
100
ꢂ33
ꢂ100
100
100
44
28
100
79
86
71
52
66
34
86
100
63
45
42
68
87
96
32
39
ꢂ11
ꢂ47
ꢂ51
100
100
ꢂ49
ꢂ27
ꢂ63
ꢂ13
ꢂ27
100
ꢂ15
ꢂ23
5
ꢂ42
ꢂ28
ꢂ30
100
ꢂ9
ꢂ19
ꢂ17
6
100
100
54
54
61
70
49
24
ꢂ13
45
100
ꢂ12
79
4-CH3Ph
2-ClPh
4-NO2Ph
Ph
4-CH3Ph
2-ClPh
4-NO2Ph
Ph
4-CH3Ph
2-ClPh
4-NO2Ph
Ph
4-CH3Ph
2-ClPh
4-NO2Ph
ꢂ100
100
100
100
100
100
100
88
92
91
33
100
100
56
87
100
100
ꢂ100
ꢂ54
ꢂ100
ꢂ100
ꢂ54
ꢂ20
ꢂ100
100
ꢂ62
ꢂ10
ꢂ69
ꢂ100
ꢂ55
87
4-CH3Ph
4-CH3Ph
4-CH3Ph
4-CH3Ph
3-ClPh
3-ClPh
3-ClPh
3-ClPh
4-ClPh
4-ClPh
4-ClPh
4-ClPh
46
ꢂ30
75
ꢂ3
ꢂ24
8
67
ꢂ55
ꢂ62
ꢂ20
100
1.06
ꢂ41
100
100
35
43
59
100
53
59
100
100
100
8
ꢂ4
27
ꢂ48
ꢂ13
5
33
66
90
Cucumber
Wheat
Stalk
Root
Stalk
Root
Compd.
Ar1
Ar2
10 mg/L
100 mg/L
10 mg/L
100 mg/L
10 mg/L
100 mg/L
10 mg/L
100 mg/L
4a
4b
4c
4d
4e
4f
4g
4h
4i
4j
4k
4l
4m
4n
4o
4p
2,4-D
Ph
Ph
Ph
Ph
Ph
ꢂ15
ꢂ45
ꢂ4
23
ꢂ1
5
24
48
53
35
ꢂ21
52
47
34
43
100
40
15
42
60
66
92
6
ꢂ11
40
100
ꢂ5
83
100
54
92
34
33
56
100
56
50
100
100
4
ꢂ2
0
7
25
31
15
64
100
14
100
100
ꢂ2
100
ꢂ13
1
100
100
1
ꢂ3
28
20
32
25
16
50
58
7
57
100
26
24
27
18
61
88
40
39
89
100
23
100
100
61
100
56
26
100
100
53
4-CH3Ph
2-ClPh
4-NO2Ph
Ph
4-CH3Ph
2-ClPh
4-NO2Ph
Ph
4-CH3Ph
2-ClPh
4-NO2Ph
Ph
4-CH3Ph
2-ClPh
4-NO2Ph
44
ꢂ2
100
ꢂ24
18
100
ꢂ15
60
4-CH3Ph
4-CH3Ph
4-CH3Ph
4-CH3Ph
3-ClPh
3-ClPh
3-ClPh
3-ClPh
4-ClPh
4-ClPh
4-ClPh
4-ClPh
ꢂ13
ꢂ12
13
12
ꢂ3
ꢂ2
ꢂ17
ꢂ6
100
12
ꢂ9
ꢂ21
ꢂ45
100
ꢂ9
ꢂ9
ꢂ37
12
ꢂ37
ꢂ61
ꢂ53
ꢂ9
100
ꢂ33
ꢂ13
100
100
ꢂ38
5
ꢂ6
26
10
12
100
95
51
100
92
40
1
under nitrogen at room temperature. After 6–8 h, the solid (C ¼ O), 1674 (C ¼ O), 1556; H NMR (400 MHz, DMSO) d:
substituted benzoylhydrazine (2 mmol) was added to the solu- 11.07 (s, 1H), 9.77 (s, 1H), 8.03 (dd, J¼ 11.1, 8.1 Hz, 4H), 7.62
tion. The mixture was stirred for additional 1 h. Then the solv- (d, J¼ 7.7 Hz, 2H), 7.50 – 7.38 (m, 6H), 7.29 (t, J¼ 7.4 Hz, 1H),
ent was evaporated, and anhydrous ethanol (25 mL) and cat. 7.20 (t, J¼ 7.4 Hz, 1H), 2.61 (s, 3H), 2.42 (s, 3H); 13C NMR
sodium ethoxide (1.5 mL, 3.0 mol/L) were added to the mix- (100 MHz, DMSO) d: 167.3 (C ¼ O), 154.9, 152.8, 152.6, 146.3,
ture. After stirring for 8–10 h at room temperature, the pre- 143.2, 138.8, 137.9, 129.5, 129.4, 129.3,128.9, 128.8, 126.5, 125.4,
cipitate was isolated by filtration and recrystallized from 124.5, 120.8, 99.9, 21.6 (PhCH3), 13.1 (SCH3); HRMS (ESI) calcd
DMSO to produce pure 5-substituted benzamido-6-aryla- for C26H22N6O2Sþ: 483.1603 [M þ H]þ, found: 483.1598.
5-(2-chlorobenzamido)-6-phenylamino-3-methylthio-1-phe-
mino-3-methylthio-1-phenyl-1H-pyrazolo[3,4-d]pyrimidin-4
(5 H)-one 4.
nyl-1H-pyrazolo[3,4-d]pyrimidin-4 (5H)-one (4c). White crys-
5-benzamido-6-phenylamino-3-methylthio-1-phenyl-1H-pyr- tals; yield: 80%; m p 290-292 ꢁC; IR (KBr, cmꢂ1): 3294, 1704
ꢀ
1
azolo[3,4-d] pyrimidin-4 (5H) -one (4a). White crystals; yield: (C ¼ O), 1689 (C ¼ O), 1561; H NMR (400 MHz, DMSO) d:
81%; m p 298-299 ꢁC; IR (KBr, cmꢂ1): 3445, 1702 (C ¼ O), 1686 11.14 (s, 1H), 9.59 (s, 1H), 8.16 – 8.10 (m, 1H), 8.03 (d,
ꢀ
(C ¼ O), 1552;1H NMR (400 MHz, DMSO) d: 11.15 (s, 1H), 9.77 J ¼ 7.7 Hz, 2H), 7.69 – 7.53 (m, 5H), 7.46 (dt, J¼ 10.9, 8.0 Hz,
(s, 1H), 8.11 (d, J¼ 7.2 Hz, 2H), 8.04 (d, J¼ 7.7 Hz, 2H), 7.69 (t, 4H), 7.30 (t, J ¼ 7.4Hz, 1H), 7.22 (t, J¼ 7.4 Hz, 1H), 2.63 (s,
J¼ 7.3 Hz, 1H), 7.61 (dd, J¼ 12.6, 6.1 Hz, 4H), 7.50 – 7.38 (m, 3H); 13C NMR (100 MHz, DMSO) d: 166.8 (C ¼ O), 154.7,
4H), 7.29 (t, J¼ 7.4 Hz, 1H), 7.21 (t, J¼ 7.4 Hz, 1H), 2.61 (s, 3H); 152.6, 152.2, 146.3, 138.7, 137.8, 133.0, 132.7, 132.1, 131.1,
13C NMR (100 MHz, DMSO) d: 169.7 (C ¼ O), 155.3, 152.2, 130.9, 129.4, 128.9, 127.4, 126.6, 125.4, 124.2, 120.9, 99.9, 13.1
151.6, 145.4, 139.6, 139.5, 139.2, 129.4, 129.3, 129.1, 128.4, 127.7, (SCH3); HRMS (ESI) calcd for C25H19ClN6O2Sþ: 503.1057
125.7, 123.4, 120.9, 120.1, 101.6, 13.1 (SCH3); HRMS (ESI) calcd [Mþ H]þ, found: 503.1051.
for C25H20N6O2Sþ: 469.1447 [M þ H]þ, found: 469.1441.
5-(4-nitrobenzamido)-6-phenylamino-3-methylthio-1-phe-
5-(4-methylbenzamido)-6-phenylamino-3-methylthio-1-phe-
nyl-1H-pyrazolo[3,4-d]pyrimidin-4 (5 H)-one (4d). Yellow
nyl-1H-pyrazolo[3,4-d]pyrimidin-4 (5H) -one (4b). White crys- crystals; yield: 74%; m p > 300 ꢁC; IR (KBr, cmꢂ1): 3319, 1714
ꢀ
1
tals; yield: 73%; m p> 300 ꢁC; IR (KBr, cmꢂ1): 3327, 1705 (C ¼ O), 1681 (C ¼ O), 1551; H NMR (400 MHz, DMSO) d:
ꢀ

PHOSPHORUS, SULFUR, AND SILICON AND THE RELATED ELEMENTS
5
11.56 (s, 1H), 9.82 (s, 1H), 8.47 (d, J ¼ 8.7 Hz, 2H), 8.33 (d, crystals; yield: 80%; m p 291-293 ꢁC; IR (KBr, cmꢂ1): 3308, 1705
ꢀ
1
J ¼ 8.7 Hz, 2H), 8.03 (d, J ¼ 7.9 Hz, 2H), 7.61 (d, J ¼ 7.9 Hz, (C ¼ O), 1679 (C ¼ O), 1549; H NMR (400 MHz, DMSO) d:
2H), 7.51 – 7.40 (m, 4H), 7.30 (t, J ¼ 7.4 Hz, 1H), 7.22 (t, 11.20 (s, 1H), 9.86 (s, 1H), 8.13 (d, J¼ 7.3 Hz, 2H), 8.05 (d,
J ¼ 7.3 Hz, 1H), 2.61 (s, 3H); 13C NMR (100 MHz, DMSO) d: J ¼ 7.8 Hz, 2H), 7.99 (t, J¼ 1.9 Hz, 1H), 7.70 (t, J ¼ 7.3 Hz, 1H),
166.0 (C ¼ O), 154.7, 152.7, 152.3, 150.3, 146.4, 138.7, 137.8, 7.65 – 7.48 (m, 5H), 7.42 (t, J ¼ 8.1 Hz, 1H), 7.34 (t, J¼ 7.4 Hz,
137.7, 130.3, 129.4, 128.9, 126.6, 125.6, 124.5, 124.1, 120.9, 1H), 7.25 (dd, J ¼ 7.9, 1.2 Hz, 1H), 2.63 (s, 3H); 13C NMR
99.8, 13.1 (SCH3); HRMS (ESI) calcd for C25H19N7O4Sþ: (100 MHz, DMSO) d: 167.5 (C ¼ O), 154.8, 152.3, 152.0, 146.4,
514.1297 [M þ H]þ, found: 514.1292.
139.5, 138.7, 133.3, 133.1, 132.1, 130.4, 129.5, 128.9, 126.7,
124.8, 123.3, 122.1, 121.1, 100.2, 13.1 (SCH3); HRMS (ESI) calcd
for C25H19ClN6O2Sþ: 503.1057 [M þ H]þ, found: 503.1051.
5-(4-methylbenzamido)-6-(3-chlorophenylamino)-3-meth-
5-benzamido-6-(4-methylphenylamino)-3-methylthio-1-phe-
nyl-1H-pyrazolo[3,4-d]pyrimidin-4 (5H)-one (4e). White crys-
tals; yield: 79%; m p > 300 ꢁC; IR (KBr, cmꢂ1): 3345, 1703
ꢀ
1
(C ¼ O), 1683 (C ¼ O), 1560; H NMR (400 MHz, DMSO) d: ylthio-1-phenyl-1H- pyrazolo[3,4-d]pyrimidin-4 (5H)-one (4j).
11.13 (s, 1H), 9.71 (s, 1H), 8.11 (d, J¼ 7.4 Hz, 2H), 8.05 (d, White crystals; yield: 73%; m p 298-299ꢁC; IR (KBr, cmꢂ1):
ꢀ
1
J¼ 7.8 Hz, 2H), 7.68 (t, J¼ 7.3 Hz, 1H), 7.60 (t, J¼ 7.5 Hz, 2H), 3303, 1701 (C ¼ O), 1670 (C ¼ O), 1551; H NMR (400 MHz,
7.54 – 7.43 (m, 4H), 7.30 (t, J¼ 7.4 Hz, 1H), 7.22 (d, J¼ 8.2 Hz, DMSO) d: 11.09 (s, 1H), 9.84 (s, 1H), 8.01 (ddd, J ¼ 12.1, 7.2,
2H), 2.61 (s, 3H), 2.32 (s, 3H); 13C NMR (100 MHz, DMSO) d: 4.9 Hz, 5H), 7.60 – 7.48 (m, 5H), 7.42 (dt, J ¼ 7.9, 3.9 Hz, 3H),
167.4 (C ¼ O), 154.9, 152.9, 152.6, 146.3, 138.8, 135.3, 134.5, 7.34 (t, J ¼ 7.4 Hz, 1H), 7.24 (dd, J ¼ 7.9, 1.1 Hz, 1H), 2.62 (s,
133.0, 132.2, 129.4, 129.2, 128.8, 126.5, 124.3, 120.8, 99.8, 21.0 3H), 2.43 (s, 3H); 13C NMR (100 MHz, DMSO) d: 167.4
(PhCH3), 13.1 (SCH3); HRMS (ESI) calcd for C26H22N6O2Sþ: (C ¼ O), 154.8, 152.3, 152.0, 146.4, 143.3, 139.5, 138.7, 133.3,
483.1603 [M þ H]þ, found: 483.1598.
130.4, 129.5, 129.4, 129.3, 128.9, 126.7, 124.7, 123.3, 122.1,
121.1, 100.2, 21.6 (PhCH3), 13.1 (SCH3); HRMS (ESI) calcd for
5-(4-methylbenzamido)-6-(4-methylphenylamino)-3-meth-
ylthio-1-phenyl-1H- pyrazolo[3,4-d]pyrimidin-4 (5H)-one (4f). C26H21ClN6O2Sþ: 517.1213 [Mþ H]þ, found: 517.1208.
White crystals; yield: 77%; m p 279-281ꢁC; IR (KBr, cmꢂ1):
5-(2-chlorobenzamido)-6-(3-chlorophenylamino)-3-meth-
ꢀ
1
3304, 1705 (C ¼ O), 1685 (C ¼ O), 1543; H NMR (400 MHz, ylthio-1-phenyl-1H- pyrazolo[3,4-d]pyrimidin-4 (5H)-one
DMSO) d: 11.03 (s, 1H), 9.68 (s, 1H), 8.02 (dd, J ¼ 18.7, 7.9 Hz, (4k). White crystals; yield: 72%; m p > 300 ꢁC; IR (KBr,
ꢀ
4H), 7.48 (dd, J ¼ 15.7, 8.3 Hz, 4H), 7.40 (d, J ¼ 8.0 Hz, 2H), cmꢂ1): 3292, 1704 (C ¼ O), 1669 (C ¼ O), 1557; H NMR
1
7.30 (t, J ¼ 7.4 Hz, 1H), 7.22 (d, J ¼ 8.3Hz, 2H), 2.60 (s, 3H), (400 MHz, DMSO) d: 11.16 (s, 1H), 9.72 (s, 1H), 8.12 (d,
2.42 (s, 3H), 2.32 (s, 3H); 13C NMR (100 MHz, DMSO) d: 167.3 J ¼ 7.0 Hz, 1H), 8.07 – 8.00 (m, 3H), 7.66 – 7.59 (m, 2H),
(C ¼ O), 154.9, 152.8, 152.6, 146.3, 143.1, 138.9, 135.3, 134.5, 7.59 – 7.49 (m, 4H), 7.44 (t, J ¼ 8.1 Hz, 1H), 7.35 (t,
129.5, 129.4, 129.3, 129.2, 128.9, 126.4, 124.2, 120.8, 99.8, 21.6 J ¼ 7.4 Hz, 1H), 7.26 (dd, J ¼ 7.9, 1.0 Hz, 1H), 2.63 (s, 3H);
(PhCH3), 21.0 (PhCH3), 13.1 (SCH3); HRMS (ESI) calcd for 13C NMR (100 MHz, DMSO) d: 166.8 (C ¼ O), 154.6, 152.2,
C27H24N6O2Sþ: 497.1760 [M þ H]þ, found: 497.1758.
151.7, 146.4, 139.5, 138.6, 133.3, 133.1, 132.6, 132.2, 131.1,
5-(2-chlorobenzamido)-6-(4-methylphenylamino)-3-meth- 131.0, 130.5, 129.5, 127.4, 126.8, 124.8, 123.1, 122.0, 121.2,
ylthio-1-phenyl-1H- pyrazolo[3,4-d]pyrimidin-4 (5H)-one 100.2,
13.1
(SCH3);
HRMS
(ESI)
calcd
for
(4g). White crystals; yield: 76%; m p > 300 ꢁC; IR (KBr, C25H18Cl2N6O2Sþ: 537.0667 [M þ H]þ, found: 537.0667.
ꢀ
1
cmꢂ1): 3314, 1750 (C ¼ O), 1701 (C ¼ O), 1543; H NMR
5-(4-nitrobenzamido)-6-(3-chlorophenylamino)-3-methyl-
(400 MHz, DMSO) d: 11.11 (s, 1H), 9.51 (s, 1H), 8.18 – 8.10 thio-1-phenyl-1H-pyrazolo[3,4-d]pyrimidin-4 (5H)-one (4 l).
(m, 1H), 8.03 (d, J ¼ 7.7 Hz, 2H), 7.71 – 7.44 (m, 8H), 7.32 Yellow crystals; yield: 73%; m p > 300 ꢁC; IR (KBr, cmꢂ1):
ꢀ
1
(dt, J ¼ 14.8, 7.4 Hz, 1H), 7.24 (d, J ¼ 8.3 Hz, 2H), 2.62 (s, 3324, 1703 (C ¼ O), 1683 (C ¼ O), 1565; H NMR (400 MHz,
3H), 2.33 (s, 3H); 13C NMR (100 MHz, DMSO) d: 168.8
DMSO) d: 11.59 (s, 1H), 9.87 (s, 1H), 8.48 (d, J ¼ 8.7 Hz, 2H),
8.34 (d, J ¼ 8.7 Hz, 2H), 8.04 (d, J ¼ 7.9 Hz, 2H), 7.98 (s, 1H),
(C ¼ O), 155.2, 152.4, 151.9, 145.8, 140.6, 139.2, 138.7, 129.4,
128.9, 128.6, 128.5, 126.0, 124.2, 122.6, 120.4, 100.8, 21.4 7.52 (t, J ¼ 7.9 Hz, 3H), 7.43 (t, J ¼ 8.1 Hz, 1H), 7.35 (t,
(PhCH3), 13.1 (SCH3); HRMS (ESI) calcd for J ¼ 7.4 Hz, 1H), 7.26 (d, J ¼ 7.9 Hz, 1H), 2.62 (s, 3H); 13C
C26H21ClN6O2Sþ: 517.1213 [M þ H]þ, found: 517.1208.
NMR (100 MHz, DMSO) d: 166.1 (C ¼ O), 154.6, 152.3, 151.7,
5-(4-nitrobenzamido)-6-(4-methylphenylamino)-3-methyl-
150.3, 146.4, 139.4, 138.6, 137.7, 133.3, 130.5, 130.4, 129.5,
thio-1-phenyl-1H-pyrazolo[3,4-d]pyrimidin-4 (5H)-one (4h). 126.8, 124.9, 124.1, 123.4, 122.2, 121.2, 100.1, 13.1 (SCH3);
Yellow crystals; yield: 71%; m p 260-266 ꢁC; IR (KBr, cmꢂ1): HRMS (ESI) calcd for C25H18ClN7O4Sþ: 548.0908 [M þ H]þ,
ꢀ
1
3319, 1695 (C ¼ O), 1669 (C ¼ O), 1573; H NMR (400 MHz, found: 548.0902.
5-benzamido-6-(4-chlorophenylamino)-3-methylthio-1-phe-
DMSO) d: 11.48 (s, 1H), 9.71 (s, 1H), 8.43 (d, J¼ 8.3 Hz, 2H), 8.32
nyl-1H- pyrazolo[3,4-d]pyrimidin-4 (5H)-one (4m). White
(d, J¼ 8.4 Hz, 2H), 8.03 (d, J¼ 7.8 Hz, 2H), 7.48 (dd, J¼ 13.5,
crystals; yield: 83%; m p 282-284 ꢁC; IR (KBr, cmꢂ1): 3303,
7.5 Hz, 4H), 7.30 (t, J¼ 7.1 Hz, 1H), 7.22 (d, J¼ 7.8 Hz, 2H), 2.60
ꢀ
1707 (C ¼ O), 1682 (C ¼ O), 1551; 1H NMR (400 MHz,
(s, 3H), 2.32 (s, 3H); 13C NMR (100 MHz, DMSO) d: 166.1
(C ¼ O), 154.7, 152.8, 152.2, 150.1, 146.3, 138.8, 138.3, 135.2, DMSO) d: 11.17 (s, 1H), 9.82 (s, 1H), 8.11 (d, J ¼ 7.4Hz, 2H),
8.01 (d, J¼ 7.8 Hz, 2H), 7.73 – 7.64 (m, 3H), 7.61 (t, J¼ 7.5 Hz,
134.6, 130.3, 129.3, 126.5, 125.2, 124.1, 120.8, 99.8, 21.0 (PhCH3),
13.0 (SCH3); HRMS (ESI) calcd for C26H21N7O4Sþ: 550.1273
2H), 7.50 (dd, J ¼ 16.4, 8.3 Hz, 4H), 7.32 (t, J ¼ 7.4 Hz, 1H), 2.61
(s, 3H); 13C NMR (100MHz, DMSO) d: 167.4 (C ¼ O), 154.8,
[M þ Na]þ, found: 550.1268.
5-benzamido-6-(3-chlorophenylamino)-3-methylthio-1-phe- 152.5, 152.3, 146.3, 138.7, 136.9, 133.1, 132.1, 129.5, 129.2,
nyl-1H- pyrazolo[3,4-d]pyrimidin-4 (5H)-one (4i). White 128.9, 128.8, 128.7, 126.7, 125.9, 121.1, 100.0, 13.1 (SCH3);

6
J. LUO ET AL.
HRMS (ESI) calcd for C25H19ClN6O2Sþ: 503.1057 [M þ H]þ,
found: 503.1051.
[3] Holla, B. S.; Mahalinga, M.; Karthikeyan, M. S.; Akberali, P. M.;
Shetty, N. S. Synthesis of Some Novel Pyrazolo[3,4-
d]Pyrimidine Derivatives as Potential Antimicrobial Agents.
Bioorg. Med. Chem. 2006, 14, 2040–2047. DOI: 10.1016/j.bmc.
2005.10.053.
[4] Tageldin, G. N.; Fahmy, S. M.; Ashour, H. M.; Khalil, M. A.; Nassra,
R. A.; Labouta, I. M. Design, Synthesis and Evaluation of Some
Pyrazolo[3,4-d]Pyrimidines as Anti-Inflammatory Agents. Bioorg.
Chem. 2018, 78, 358–371. DOI: 10.1016/j.bioorg.2018.03.030.
[5] Khobragade, C. N.; Bodade, R. G.; Konda, S. G.; Dawane, B. S.;
Manwar, A. V. Synthesis and Antimicrobial Activity of Novel
Pyrazolo[3,4-d]Pyrimidin Derivatives. Eur. J. Med. Chem. 2010,
45, 1635–1638.
5-(4-methylbenzamido)-6-(4-chlorophenylamino)-3-
methylthio-1-phenyl-1H-
pyrazolo[3,4-d]pyrimidin-4
(5H)-one (4n). White crystals; yield: 77%; m p > 300 ꢁC;
ꢀ
IR (KBr, cmꢂ1): 3306, 1696 (C ¼ O), 1678 (C ¼ O), 1552;
1H NMR (400 MHz, DMSO) d: 8.03 (t, J ¼ 9.4 Hz, 2H),
7.89 (d, J ¼ 8.0 Hz, 2H), 7.70 – 7.64 (m, 2H), 7.51 (t,
J ¼ 8.0 Hz, 2H), 7.39 (d, J ¼ 8.9 Hz, 2H), 7.29 (dd, J ¼ 13.5,
6.2 Hz, 1H), 7.12 (d, J ¼ 8.0 Hz, 2H), 2.58 (s, 3H), 2.21 (s,
3H); 13C NMR (100 MHz, DMSO) d: 168.7 (C ¼ O), 155.7,
152.8, 151.9, 145.5, 140.6, 139.6, 139.5, 134.9, 129.4, 128.7,
128.5, 128.4, 126.2, 125.5, 123.4, 120.1, 100.8, 21.4
(PhCH3), 13.0 (SCH3); HRMS (ESI) calcd for
C26H21ClN6O2Sþ: 517.1213 [M þ H]þ, found: 517.1208.
5-(2-chlorobenzamido)-6-(4-chlorophenylamino)-3-meth-
ylthio-1-phenyl-1H- pyrazolo[3,4-d]pyrimidin-4 (5 H)-one
[6] Moukha-Chafiq, O.; Taha, M. L.; Lazrek, B. H.; Barascut, J. L.;
Imbach, J. L. Synthesis of Some Acyclonucleosides with the
Alkylating Chain of Acyclovir. C. R. Acad. Sci. IIc: Chem. 2000,
3, 639–641. DOI: 10.1016/S1387-1609(00)01157-9.
[7] Chauhan, M.; Kumar, R. Medicinal Attributes of Pyrazolo[3,4-
d]Pyrimidines:
A Review. Bioorg. Med. Chem. 2013, 21,
5657–5668. DOI: 10.1016/j.bmc.2013.07.027.
ꢀ
[8] Cherukupalli, S.; Chandrasekaran, B.; Krystof, V.; Aleti, R. R.;
(4o). White crystals; yield: 73%; m p > 300 ꢁC; IR (KBr,
Sayyad, N.; Merugu, S. R.; Kushwaha, N. D.; Karpoormath, R.
Synthesis, Anticancer Evaluation, and Molecular Docking
Studies of Some Novel 4,6-Disubstituted Pyrazolo[3,4-
ꢀ
1
cmꢂ1): 3311, 1708 (C ¼ O), 1693 (C ¼ O), 1556; H NMR
(400 MHz, DMSO) d: 11.15 (s, 1H), 9.69 (s, 1H), 8.16 – 8.10
(m, 1H), 8.00 (d, J ¼ 7.7 Hz, 2H), 7.73 – 7.67 (m, 2H), 7.66
– 7.46 (m, 7H), 7.33 (t, J ¼ 7.4 Hz, 1H), 2.63 (s, 3H); 13C
NMR (100 MHz, DMSO) d: 166.8 (C ¼ O), 154.7, 152.4,
152.0, 146.4, 138.6, 136.9, 133.1, 132.6, 132.2, 131.1, 131.0,
129.5, 129.2, 128.8, 127.4, 126.8, 125.7, 121.1, 100.0, 13.1
(SCH3); HRMS (ESI) calcd for C25H18Cl2N6O2Sþ: 537.0667
[M þ H]þ, found: 537.0662.
d]Pyrimidines as Cyclin-Dependent Kinase
2
(CDK2)
Inhibitors. Bioorg. Chem. 2018, 79, 46–49. DOI: 10.1016/j.bio-
org.2018.02.030.
[9] Abd El Razik, H. A.; Mroueh, M.; Faour, W. H.; Shebaby,
W. N.; Daher, C. F.; Ashour, H. M. A.; Ragab, H. M. Synthesis
of New Pyrazolo[3,4-d]Pyrimidine Derivatives and Evaluation
of Their Anti-Inflammatory and Anticancer Activities. Chem.
Biol. Drug Des. 2017, 90, 83–96. DOI: 10.1111/cbdd.12929.
[10] Liu, H.; Wang, H. Q.; Ding, M. W.; Liu, Z. J.; Xiao, W. J. A
Novel Synthesis and Herbicidal Activity of Fluorine-Containing
Pyrazolo[3,4-d]Pyrimidin-4-One Derivatives. J. Fluor. Chem.
2006, 127, 1584–1590. DOI: 10.1016/j.jfluchem.2006.08.008.
[11] Nie, Y. B.; Wang, L.; Ding, M. W. Synthesis of 1,2,4,5-
Tetrasubstituted Imidazoles by a Sequential aza-Wittig/Michael/
Isomerization Reaction. J. Org. Chem. 2012, 77, 696–700. DOI:
10.1021/jo201846w.
5-(4-nitrobenzamido)-6-(4-chlorophenylamino)-3-
methylthio-1-phenyl-1H-
pyrazolo[3,4-d]pyrimidin-4
(5H)-one (4p). Yellow crystals; yield: 75%; m p > 300 ꢁC;
ꢀ
IR (KBr, cmꢂ1): 3311, 1704 (C ¼ O), 1684 (C ¼ O), 1558;
1H NMR (400 MHz, DMSO) d: 11.59 (s, 1H), 9.86 (s, 1H),
8.48 (d, J ¼ 8.2 Hz, 2H), 8.32 (d, J ¼ 8.3 Hz, 2H), 8.00 (d,
J ¼ 7.7 Hz, 2H), 7.66 (d, J ¼ 8.3 Hz, 2H), 7.49 (d,
J ¼ 8.4 Hz, 4H), 7.33 (t, J ¼ 6.9 Hz, 1H), 2.61 (s, 2H); 13C
NMR (100 MHz, DMSO) d: 166.0 (C ¼ O), 154.6, 152.5,
152.0, 150.3, 146.4, 138.6, 137.9, 136.8, 130.3, 129.5, 129.3,
128.8, 126.8, 125.9, 124.1, 121.1, 99.9, 13.1 (SCH3); HRMS
(ESI) calcd for C25H18ClN7O4Sþ: 548.0908 [M þ H]þ,
found: 548.0902.
[12] Wang, T.; Ke, X. X.; Zhou, S. T.; Chen, H. Z. New Efficient
Synthesis of 5,6-Disubstituted-3-Phenyl-1,2,3-Triazolo[4,5-
d
]Pyrimidin-7-Ones via a Tandem aza-Wittig Reaction. Synth.
Commun 2012, 42, 1393–1400. DOI: 10.1080/00397911.2010.
535940.
[13] Wang, H. Q.; Zhou, W. P.; Wang, Y. Y.; Lin, C. R. Synthesis
and Antifungal Activities of Novel 5-Amino-6-Arylamino-1H-
Pyrazolo[3,4-d]Pyrimidin-4(5H)-One Derivatives. J. Agric. Food
Chem. 2008, 56, 7321–7325. DOI: 10.1021/jf801359f.
[14] Yang, Y. Y.; Shou, W. G.; Chen, Z. B.; Hong, D.; Wang, Y. G.
A
Tandem Approach to Isoquinolines from 2-Azido-3-
Funding
Arylacrylates and Alpha-Diazocarbonyl Compounds. J. Org.
Chem. 2008, 73, 3928–3930. DOI: 10.1021/jo8003259.
We thank the National Natural Science Foundation of China (No.
21562026, 21762025) and the Natural Science Foundation of Jiangxi
Province in China (No. 20161BAB213072) for their financial support.
[15] Zhao, J. F.; Xie, C.; Xu, S. Z.; Ding, M. W.; Xiao, W.
Iminophosphorane-Mediated Efficient Synthesis of New
Tricyclic 3,5-Dihydro-1,2,3-Triazolo[4,5-d]-1,2,4-Triazolo[1,5-
a]Pyrimidin-9-Ones. Org. Biomol. Chem. 2006, 4, 130–134.
DOI: 10.1039/b513715b.
[16] Bonini, C.; Auria, M. D.; Funicello, M.; Romaniello, G. Novel
N-(2-Benzo[b]Thienyl)Iminophosphoranes and Their Use in
the Synthesis of Benzo[b]Thieno[2,3-b]Pyridines. Tetrahedron
2002, 58, 3507–3512. DOI: 10.1016/S0040-4020(02)00324-1.
[17] Wang, T.; Xiong, J.; Wang, W. J.; Li, R.; Tang, X. L.; Xiong, F.
Tunable Regioselective Synthesis of Pyrazolo[3,4-d]Pyrimidine
Derivatives via aza-Wittig Cyclization and Dimroth-Type
Rearrangement. RSC Adv. 2015, 5, 19830–19837. DOI: 10.1039/
C4RA15777J.
References
[1] Wu, M. H.; Hu, J. H.; Guo, H. B.; Li, Y. A Facile and Efficient
One-Pot Three-Step Protocol for Synthesis of 6-aryl-7-oxo-5-
aryoxy/alkoxy-1-(p-tolyl)-6,7-dihydro-1H-pyrazolo[4,3-d]pyr-
imidine-3-carbonitrile. Arkivoc 2012, 6, 295–303.
[2] Rashad, A. E.; Hegab, M. I.; Abdel-Megeid, R. E.; Micky, J. A.;
Abdel-Megeid, F. M. E. M. Synthesis and Antiviral Evaluation
of Some New Pyrazole and Fused Pyrazolopyrimidine
Derivatives. Bioorg. Med. Chem. 2008, 16, 7102–7106. DOI: 10.
1016/j.bmc.2008.06.054.
[18] Chen, C. N.; Lv, L. L.; Ji, F. Q.; Chen, Q.; Xu, H.; Niu, C. W.; Xi,
Z.; Yang, G. F. Design and Synthesis of N-2,6-Difluorophenyl-5-
Methoxyl-1,2,4-Triazolo[1,5-a]-Pyrimidine-2-Sulfonamide
as

PHOSPHORUS, SULFUR, AND SILICON AND THE RELATED ELEMENTS
7
Acetohydroxyacid Synthase Inhibitor. Bioorg. Med. Chem. 2009,
17, 3011–3017. DOI: 10.1016/j.bmc.2009.03.018.
d]pyrimidin-4-ones. Chin. J. Chem. 2010, 30, 1749–1753.
DOI: 10.1002/cjoc.201290000.
[19] Molina, P.; Vilaplana, M. Iminophosphoranes: Useful Building [21] Luo, J.; Zhao, A. L.; Zheng, C. H.; Wang, T. Synthesis and
Blocks for the Preparation of Nitrogen-Containing Heterocycles.
Synthesis 1994, 12, 1197–1218. DOI: 10.1055/s-1994-25672.
[20] Wang, T.; Luo, J.; Zheng, C. H. Synthesis and Herbicidal
Herbicidal Activity of Novel 6-Arylthio-3-Methylthio-1 H-
Pyrazolo[3,4-d]Pyrimidin-4(5 H )-Ones. Phosphorus Sulfur Silicon
Relat. Elem. 2017, 192, 1124–1126. DOI: 10.1080/10426507.2017.
1333508.
Activity
of
3,6-Dialkylthio-1-phenyl-pyrazolo[3,4-