A novel solid-phase synthetic method for production of N-alkyl-4-alkylamino-1-aryl-1H-pyrazolo[3,4-d]pyrimidine-6-carboxamide library

Accepted Manuscript

A novel solid-phase synthetic method for production of N-alkyl-4-alkylamino-1-

aryl-1H-pyrazolo[3,4-d]pyrimidine-6-carboxamide library

Yun-Jeong Heo, Moon-Kook Jeon

PII:

S0040-4020(17)30884-0

10.1016/j.tet.2017.08.044

TET 28938

DOI:

Reference:

To appear in: Tetrahedron

Received Date: 1 June 2017

Revised Date: 14 August 2017

Accepted Date: 21 August 2017

Please cite this article as: Heo Y-J, Jeon M-K, A novel solid-phase synthetic method for production of N-

alkyl-4-alkylamino-1-aryl-1H-pyrazolo[3,4-d]pyrimidine-6-carboxamide library, Tetrahedron (2017), doi:

10.1016/j.tet.2017.08.044.

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ACCEPTED MANUSCRIPT

Graphical Abstract

A novel solid-phase synthetic method for

production of N-alkyl-4-alkylamino-1-aryl-

1H-pyrazolo[3,4-d]pyrimidine-6-

carboxamide library

Leave this area blank for abstract info.

Yun-Jeong Heo^{a, b}and Moon-Kook Jeon^a,

a) Bio & Drug Discovery Division, Korea Research Institute of Chemical Technology, 141 Gajeong-ro,

Yuseong-gu, Daejeon 305-600, Republic of Korea. b) Department of Chemistry, Korea University, 145 Anam-

ro, Seongbuk-gu, Seoul 136-713, Republic of Korea

ACCEPTED MANUSCRIPT

Tetrahedron

journal homepage: www.elsevier.com

A novel solid-phase synthetic method for production of N-alkyl-4-alkylamino-1-aryl-

1H-pyrazolo[3,4-d]pyrimidine-6-carboxamide library

Yun-Jeong Heo^{a, b}and Moon-Kook Jeon^a,

^aBio & Drug Discovery Division, Korea Research Institute of Chemical Technology, 141 Gajeong-ro, Yuseong-gu, Daejeon 305-600, Republic of Korea

^bDepartment of Chemistry, Korea University, 145 Anam-ro, Seongbuk-gu, Seoul 136-713, Republic of Korea

ARTICLE INFO

ABSTRACT

Article history:

Received

Received in revised form

Accepted

This work describes a solid-phase synthetic method for building a compound library of N-alkyl-

4-alkylamino-1-aryl-1H-pyrazolo[3,4-d]pyrimidine-6-carboxamide derivatives, that are based on

the biologically active 1-aryl-1H-pyrazolo[3,4-d]pyrimidine scaffold. In the first step of this

synthetic sequence, condensation reactions of ethyl 5-amino-1-aryl-1H-pyrazole-4-carboxylates

with methyl cyanoformate resulted in the formation of esters that underwent hydrolysis to give

1-aryl-4,5-dihydro-1H-pyrazolo[3,4-d]pyrimidin-4-one-6-carboxylic acids. The coupling

reaction of these carboxylic acids with primary alkylamine-loaded acid-sensitive

methoxybenzaldehyde (AMEBA) resins was followed by amination reactions mediated by

benzotriazol-1-yloxytris(dimethylamino)phosphonium hexafluorophosphate (BOP). Subsequent

cleavage from the solid support resulted in the formation of the target N-alkyl-4-alkylamino-1-

aryl-1H-pyrazolo[3,4-d]pyrimidine-6-carboxamide derivatives. The reaction conditions for

solid-phase transformations were optimized using a solution-phase model study with 2,4-

dimethoxybenzyl-protected isobutylamine as a reactant in place of the AMEBA resin-loaded

isobutylamine. The progress of the solid-phase reactions was monitored by on-bead ATR-FTIR

spectroscopy. Diversification experiments were performed by using 1-aryl-4,5-dihydro-1H-

pyrazolo[3,4-d]pyrimidin-4-one-6-carboxylic acids and a variety of primary and secondary

amine building blocks to build the target compound library.

Available online

Keywords:

Screening library

Privileged structure

Heterocycle

Pyrazolopyrimidine

Solid-phase organic synthesis

.

workers⁴two and a half decades ago as one of the most common

approaches towards scaffold selection for the production of both

diversity and focused screening libraries.⁶

1. Introduction

Small organic molecule screening libraries, including diverse

and target-focused libraries, serve as important sources for hit

and lead generation in the drug discovery process.^1,2Solid-phase

organic synthesis (SPOS) provides an efficient synthetic route to

small organic molecule libraries when its operational procedures

are set up appropriately.³This reaction methodology involves the

attachment of a synthetic intermediate onto a solid polymeric

support via a linker, followed by repeated reactions on the solid

phase with filtration and washing steps, and finally cleavage from

the solid support to afford the desired product. Reactions on the

solid phase can be driven to completion by the use of excess

reagents and supported intermediates can be purified by simple

filtration and washing steps. Therefore, SPOS can be automated

and mix-and-split synthesis is also made possible.

As shown in Figure 1 (together with values for some of its

physicochemical

properties),⁷

1-aryl-1H-pyrazolo[3,4-

d]pyrimidine derivatives are biologically active and exhibit

A₁/A_2Aantagonistic,^8a-bGPR119 agonistic,^8cp38α inhibitory,^8d

anticancer/radioprotective,^8eCRF-1 receptor antagonistic,^8f

glucokinase activating,^8gGLUT1 inhibitory,^8hand COX-2

inhibitory⁸ⁱeffects. These properties arise from the difference in

the substituents around the 1-aryl-1H-pyrazolo[3,4-d]pyrimidine

scaffold. Therefore, this scaffold can be regarded as a privileged

structure that exhibits a broad range of biological activities, and

one that can yield promising libraries when appropriately

modified. A few reports have been published regarding the

synthesis of 1-aryl-1H-pyrazolo[3,4-d]pyrimidine derivatives in a

high-throughput manner.⁹Lindsley and co-workers have reported

the microwave-assisted organic synthesis (MAOS) of 4-amino-1-

aryl-1H-pyrazolo[3,4-d]pyrimidine derivatives via 4-cyano-5-

aminopyrazole precursors, which in turn were prepared from

ethoxymethylenemalononitrile and hydrazines.^9aSlavish et al.

The privileged structure concept has been a stepping stone

towards enhancing small organic molecule screening libraries.^4-6

A privileged structure can be defined as a structural motif that

possesses different biological activities depending on its

substitution pattern. Despite its conceptual ambiguity,⁵this

concept has prevailed since its first introduction by Evans and co-

———

Corresponding author. Tel.: +82-42-860-7694; fax: +82-42-860-7160; e-mail: moteta@krict.re.kr

2

Tetrahedron

ACCEPTED MANUSCRIPT

described a sequential introduction of the aniline and hydrazine

O

N

O

NH

building blocks onto 2,4,6-trichloropyrimidine-5-carboxaldehyde

to form a 4,6-bis(anilino)-1-aryl-1H-pyrazolo[3,4-d]pyrimidine

library.^9bMorrill and co-workers have reported the synthesis of

4-substituted 1-aryl-1H-pyrazolo[3,4-d]pyrimidine derivatives

via condensation reactions of 4,6-dichloropyrimidine-5-

carboxaldehyde with hydrazines and subsequent substitution

reactions with various nucleophiles at the 4-position.^9cLiao et al.

have developed a solid-phase synthetic route for pyrazolo[3,4-

d]pyrimidine derivatives via Aza-Wittig/electrocyclic ring

closure reaction.^9dThere is a continuing interest in high-

throughput chemistry within the scientific community for hit- and

lead-finding heterocyclic compound screening libraries.

Therefore, in this work, the biologically active 1-aryl-1H-

pyrazolo[3,4-d]pyrimidine scaffold was chosen as a candidate.

Herein, a novel solid-phase synthetic method has been reported

for the development of an N-alkyl-4-alkylamino-1-aryl-1H-

N

NH

O

N

OMe

PS

O

N

R¹

N

Ar

OH

template loading

N

Ar

N

H

R¹

PS

O

OMe

direct

amination

R²R³

N

R²R³

N

PS

O

cleavage

N

Ar

N

HN

R¹

OMe

Figure 2. Solid-phase synthetic strategy for N-alkyl-4-alkylamino-1-aryl-1H-

pyrazolo[3,4-d]pyrimidine-6-carboxamide derivatives.

2. Results and discussion

The synthesis of 1-aryl-4,5-dihydro-1H-pyrazolo[3,4-

d]pyrimidin-4-one-6-carboxylic acids (4) started from

preparation of ethyl 5-amino-1-aryl-1H-pyrazole-4-carboxylates

(2). The latter compounds were synthesized by condensation

reactions between ethyl 2-cyano-3-ethoxyacrylate (1) and aryl

hydrazines that were present either as a free form (for Ar = C₆H₅)

or HCl salt form (for Ar = 4-MeOC₆H₄, 4-MeC₆H₄, 4-FC₆H₄, and

4-NCC₆H₄) in EtOH at 80 °C, as shown in Scheme 1. The

pyrazole intermediates (2) underwent cyclization with methyl

cyanoformate in the presence of 4 N HCl in 1,4-dioxane at 100

°C to give the ester intermediates 3. These esters (3) were readily

hydrolyzed on treatment with lithium hydroxide in MeOH/H₂O at

room temperature to afford the desired 4,5-dihydro-1H-

pyrazolo[3,4-d]pyrimidin-4-one-6-carboxylic acids (4). The

overall results are summarized in Table 1. The known

compounds 2a,^11a2b,^11a2c,^11b2d,^11cand 2e^11dwere characterized

by ¹H NMR and MS. Both compounds 3 and 4 except 3a^11ehave

been reported in this work for the first time and were completely

pyrazolo[3,4-d]pyrimidine-6-carboxamide

library.

This

procedure involves loading of 1-aryl-4,5-dihydro-1H-

pyrazolo[3,4-d]pyrimidin-4-one-6-carboxylic acid templates onto

aminated acid-sensitive methoxybenzaldehyde (AMEBA)

resins,¹⁰

followed

by

benzotriazol-1-

hexafluorophosphate

yloxytris(dimethylamino)phosphonium

(BOP)-mediated direct amination reactions at the 4-position, and

final cleavage reactions to obtain the target compounds, as

illustrated in Figure 2. This work describes the synthesis of 1-

aryl-4,5-dihydro-1H-pyrazolo[3,4-d]pyrimidin-4-one-6-

carboxylic acids, a solution-phase model study and its adaptation

to develop the solid-phase synthetic method, on-bead monitoring

of solid-phase reactions by ATR (attenuated total reflectance)-

FTIR spectroscopy, and the effect of varying substituents.

characterized by their melting point, H and ¹³C NMR, IR, MS,

1

and HRMS.

o

Scheme 1. i) (Et₃N,) EtOH, 80 C; ii) 4N HCl in 1,4-dioxane, 100 C; iii)

LiOH^.H₂O, MeOH/H₂O, rt.

Table 1. Yields of compounds 2a-e, 3a-e, and 4a-e

Compound

Ar

Yield (%)

2a

2b

2c

2d

2e

3a

3b

3c

3d

3e

4a

4b

4c

C₆H₅

90

78

85

65

80

78

72

43

71

88

90

81

90

4-MeO-C₆H₄

4-Me-C₆H₄

4-F-C₆H₄

4-NC-C₆H₄

C₆H₅

4-MeO-C₆H₄

4-Me-C₆H₄

4-F-C₆H₄

4-NC-C₆H₄

C₆H₅

Figure 1. Representative biologically active 1-aryl-1H-pyrazolo[3,4-

d]pyrimidine derivatives.

4-MeO-C₆H₄

4-Me-C₆H₄

4d

4e

4-F-C₆H₄

81

8

proton sponge

rt

9 h

71

12

ACCEPTED MANUSCRIPT

4-NC-C₆H₄

90

9

TMG

20 h

^aEach reaction was run for 6 (50 mg, 0.11 mmol) in the presence of BOP (62

mg, 0.22 mmol) and a base (1.5 molar eq.) in DMF (3 mL).

A solution-phase model study for optimization of reaction

conditions was performed using the synthesized carboxylic acid

4a (Scheme 2) and 2,4-dimethoxybenzyl-protected isobutylamine

5¹²as a substitute for the AMEBA resin-loaded isobutylamine in

an amide coupling reaction. The reaction was carried out in the

presence of EDC and HOAt in DMF at room temperature and the

carboxamide derivative 6 was obtained in 85% yield. No

significant side reactions were observed during this

transformation. BOP-mediated direct amination reaction¹³of 6

with benzylamine was optimized by varying the base and

reaction temperature as shown in Table 2. DMF was selected as

the reaction solvent instead of acetonitrile because it assists in

resin-swelling during the solid-phase reactions.¹⁴Typical

coupling reaction conditions such as the combination of BOP and

DBU did not provide satisfactory results at ambient or elevated

temperature (entry 1-3). Using DBN as a base at room

temperature resulted in no formation of the desired product (entry

4) but when DIPEA was used under identical reaction conditions,

the product yield considerably improved to 84% (entry 5).

Elevating the reaction temperature to 60 °C gave only a slightly

higher product yield of 87% (entry 6). Other bases such as TEA,

proton sponge, and TMG at room temperature afforded the

benzylaminated product 7 in 49, 71, and 12% yields respectively.

From the above results, the combination of BOP/DIPEA was

selected as standard conditions for subsequent reactions. After

the deprotection of compound 7 using TFA in DCM, the final

target compound 8a was obtained in 91% yield. Compounds 6, 7,

and 8a have not been reported before and were therefore

In the next step, the optimized reaction parameters determined

from the solution-phase model study were utilized for solid-phase

synthesis, as shown in Scheme 3. Isobutylamine loaded onto

AMEBA resin (9a) was prepared by reductive amination of

AMEBA resin¹⁵with isobutylamine 16a under typical conditions.

The reaction conditions set for the solution model study were

applied to 9a to give a template-loaded intermediate resin 10a

and a benzylaminated intermediate resin 11a. The final product

8a was then obtained by cleavage from the resin 11a under the

same conditions as those used for compound 7. Subsequent

purification by silica gel column chromatography gave 8a in a

70% five-step overall isolated yield from the Merrifield resin.

The progress of the solid-phase reactions was monitored by

ATR-FTIR spectroscopy of resin samples withdrawn during the

course of the reactions. The IR spectra of the Merrifield and

AMEBA resins, compounds 9a, 10a, and 11a are given in Figure

3, together with those of the corresponding compounds 5, 6, and

7 obtained from the above solution-phase model study for

comparison. In the transformations of AMEBA resin to 9a and

10a to 11a, the characteristic carbonyl bands at 1671 cm^-1and

1709 cm^-1, respectively, disappeared from the IR spectra of the

products. Furthermore, the IR spectra for resins 10a and 11a

were comparable to those of compounds 6 and 7, respectively.

OMe

CHO

OMe

H₂

N

CHO

HO

N

PS Cl

H

1

(ref. 15)

i)

characterized by their melting points, H and ¹³C NMR, IR, MS,

PS

O

PS

Merrifield resin

(1.27 mmol/g)

9a

AMEBA resin

and HRMS.

O

NH

N

O

N

O

N

NH

OH

NH₂

4a

NH

N

PS

O

PS

O

N

ii)

iii)

N

OMe

10a

11a

NH

N

70% five-step overall isolated yield from Merrifield resin

O

N

iv)

N

HN

8a

Scheme 3. i) NaBH(OAc)₃, DCE, rt, 21 h; ii) EDC, HOAt, DMF, rt, 19 h; iii)

BOP, DIPEA, DMF, rt, 13 h; iv) 25% TFA in DCM, rt, 1 h.

Scheme 2. i) EDC, HOAt, DMF, rt, 8 h, 85% for 6; ii) BOP, DIPEA, DMF,

rt, 7 h, 84% for 7; iii) 25% TFA in DCM, rt, 3 h, 91% for 8a.

The effect of different substituents on these reactions was also

studied (Scheme 4). The building blocks used in these

experiments are shown in Figure 4. Isobutyl and benzylamino

groups were chosen as R¹and NR²R³groups respectively, and

the aryl group was varied by using 1-aryl-4,5-dihydro-1H-

Table 2. Variation experiments of reaction conditions for direct

amination of intermediate 6 to 7^a

Entry

Base

Reaction temp.

Reaction time

Yield (%) for 7

pyrazolo[3,4-d]pyrimidin-4-one-6-carboxylic

acids

(4b−e).

1

2

3

4

5

6

7

DBU

rt

14 h

13 h

14 h

12 h

7 h

22

40

46

-

These transformations resulted in the formation of the

corresponding products 8b−e in 50−71% overall yields from

Merrifield resin, as summarized in Table 3. The primary amines

shown in Figure 4 were utilized for the diversity point R¹and the

NR²R³group was fixed with the cyclopropylamino group. In

DBU

60 ^oC

100 ^oC

rt

DBU

DBN

these

transformations,

1H-pyrazolo[3,4-d]pyrimidine-6-

DIPEA

TEA

rt

84

87

49

carboxamide derivatives 8f−o were formed with overall isolated

yields of 31−77% after a five-step sequence. With R¹group as

cyclopropyl, the NR²R³group was varied by using primary and

secondary amines (illustrated in Figure 4) and the final products

60 ^oC

rt

14 h

7 h

4

Tetrahedron

ACCEPTED MANUSCRIPT

Figure 4. Building blocks used in variation experiments of substituents.

Table 3. Yields of compounds 8b-y

Compd

Ar

R¹

NR²R³

Yield (%)^a

8b

8c

8d

8e

8f

4-MeO-C₆H₄

4-Me-C₆H₄

4-F-C₆H₄

4-NC-C₆H₄

C₆H₅

i-Bu

benzylamino

71

50

61

63

72

77

i-Bu

piperonyl

cyclopropylamino

8g

C₆H₅

(4-

methoxycarbonyl)b

enzyl

cyclopropylamino

8h

8i

4-MeO-C₆H₄

pyridin-4-ylmethyl

76

51

2-

methoxyphenethyl

cyclopropylamino

8j

4-Me-C₆H₄

3,4-

55

dimethoxyphenethy

l

Figure 3. Stacked IR spectra of resins (Merrifield resin, AMEBA resin, 9a,

10a, and 11a) and compounds (5, 6 and 7).

cyclopropylamino

8k

8l

4-Me-C₆H₄

4-F-C₆H₄

2-(thiophen-2-

yl)ethyl

31

45

50

8p−y were obtained in 34−71% yields. The N-Alkyl-4-

alkylamino-1-aryl-1H-pyrazolo[3,4-d]pyrimidine-6-carboxamide

derivatives 8b−y have not been synthesized before and were

2-(pyrrolidin-1-

yl)ethyl

1

characterized in this work by their melting points, H and ¹³C

8m

2-(piperidin-1-

yl)ethyl

NMR, IR, MS, and HRMS. ATR-FTIR data were recorded for

cyclopropylamino

8n

8o

4-NC-C₆H₄

2-morpholinoethyl

48

53

2-(1-

methylpyrrolidin-2-

yl)ethyl

8p

8q

C₆H₅

cyclopropyl

piperonylamino

69

60

(pyridin-4-

ylmethyl)amino

8r

8s

8t

4-MeO-C₆H₄

4-Me-C₆H₄

cyclopropyl

(1-benzylpiperidin-4-

yl)amino

71

61

49

the intermediate resins 9, 10, and 11.

(2-(piperidin-1-

yl)ethyl)amino

Scheme 4. i) NaBH(OAc)₃, DCE, rt; ii) EDC, HOAt, DMF, rt; iii) BOP,

DIPEA, DMF, rt; iv) 25% TFA in DCM, rt.

(2-

morpholinoethyl)ami

no

8u

4-Me-C₆H₄

cyclopropyl

(2-

34

Compound 5¹²was prepared on the basis of previous literature

ACCEPTED MANUSCRIPT

1

(diethylamino)ethyl)(

methyl)amino

method and were obtained in H NMR spectroscopically pure

form. AMEBA resin was prepared using a literature method.¹⁵

Most of solvents were purchased from Burdick & Jackson and

were HPLC grade. Melting points were measured using a Mettler

Toledo FP900 Thermo System. ATR-FTIR spectra were recorded

8v

4-F-C₆H₄

cyclopropyl

morpholino

56

69

8w

4-(2-

1

on a IdentifyIR (Smiths Scientific) spectrophotometer. H NMR

furoyl)piperazin-1-yl

spectra were recorded on a Varian VNMRS 300 or a Bruker

Avance 500 spectrophotometer at rt. ¹³C NMR spectra were

recorded on a Bruker Avance 500 spectrophotometer at rt. NMR

solvents such as CDCl₃and DMSO-d₆were purchased from

Cambridge Isotope Laboratories, Inc. MS analyses were

performed on a Micromass Quattro micro mass spectrometer

equipped with PDA (200-400 nm) detection using Acquity UPLC

BEH column (C₁₈, 1.7 µm, 2.1 × 50 mm) and typical gradient

was 5-95% CH₃CN/H₂O containing 0.1% trifluoroacetic acid.

HRMS analyses were performed on a JEOL MStation JMS-700

spectrometer.

8x

8y

4-NC-C₆H₄

cyclopropyl

4-(pyrrolidin-1-

yl)piperidin-1-yl

50

49

4-(3-

methoxyphenyl)piper

azin-1-yl

^aFive-step overall isolated yield from Merrifield resin (loading capacity 1.27

mmol/g).

3. Conclusion

In this work, a solid-phase synthetic method for N-alkyl-4-

alkylamino-1-aryl-1H-pyrazolo[3,4-d]pyrimidine-6-carboxamide

derivatives has been developed. Coupling of 1-aryl-4,5-dihydro-

1H-pyrazolo[3,4-d]pyrimidin-4-one-6-carboxylic acids with

primary alkylamine-loaded AMEBA resins was followed by

BOP-mediated amination reactions and subsequent cleavage

from the solid support afforded the desired compounds. 1-Aryl-

4,5-dihydro-1H-pyrazolo[3,4-d]pyrimidin-4-one-6-carboxylic

acids were prepared from the condensation reactions of ethyl 5-

4.2. Synthetic procedures

Ethyl 5-amino-1-phenyl-1H-pyrazole-4-carboxylate (2a): A

mixture of ethyl 2-cyano-3-ethoxyacrylate (3.00 g, 17.7 mmol)

and phenyl hydrazine (1.75 mL, 17.7 mmol) in ethanol (75 mL)

was stirred at 0 °C for 1 h. Then, the mixture was stirred at 80 °C

for 5 h. After cooling the reaction mixture to room temperature,

ethanol was removed in vacuo and the residue was partitioned

between ethyl acetate and water. The organic layer was dried

over magnesium sulfate. The solvent was evaporated in vacuo

and the residue was chromatographed on a silica gel column with

a mixture of n-hexane and ethyl acetate (6:1) to give the desired

product 2a (3.71 g, 90%). ¹H NMR (300 MHz, CDCl₃): δ=7.79 (s,

1H), 7.52 (m, 4H), 7.40 (m, 1H), 5.30 (br s, 2H), 4.30 (q, J=7.1

Hz, 2H), 1.36 (t, J=7.1 Hz, 3H) ppm; MS (ESI): m/z: 232 [M+H⁺].

amino-1-aryl-1H-pyrazole-4-carboxylates

with

methyl

cyanoformate, followed by hydrolysis of the resulting esters with

lithium hydroxide. The reaction conditions for solid-phase

synthesis were optimized by a solution-phase model study using

2,4-dimethoxybenzyl-protected isobutylamine, which was used

as a surrogate for the AMEBA resin-loaded isobutylamine. The

progress of the solid-phase reactions was monitored by on-bead

ATR-FTIR spectroscopy. Diversification experiments were

performed by using 1-aryl-4,5-dihydro-1H-pyrazolo[3,4-

d]pyrimidin-4-one-6-carboxylic acids and a variety of primary

and secondary amine building blocks to validate the utility of the

established solid-phase synthetic method for the construction of

the N-alkyl-4-alkylamino-1-aryl-1H-pyrazolo[3,4-d]pyrimidine-

6-carboxamide library. The abovementioned results suggest that

the synthetic method would be a viable route towards creating

structurally more diverse N-alkyl-4-alkylamino-1-aryl-1H-

pyrazolo[3,4-d]pyrimidine-6-carboxamide derivatives in a high-

throughput fashion.

Ethyl

5-amino-1-(4-methoxyphenyl)-1H-pyrazole-4-

carboxylate (2b): To ethyl 2-cyano-3-ethoxyacrylate (2.00 g,

11.8 mmol) and 4-methoxyphenyl hydrazine hydrochloride (2.06

g, 11.8 mmol) in ethanol (75 mL) at room temperature was added

triethylamine (1.65 mL, 11.8 mmol). The mixture was stirred at

80 °C for 8 h. After cooling the reaction mixture to room

temperature, ethanol was removed in vacuo and the residue was

partitioned between ethyl acetate and water. The organic layer

was dried over magnesium sulfate. The solvent was evaporated in

vacuo and the residue was chromatographed on a silica gel

column with a mixture of n-hexane and ethyl acetate (3:1) to give

the desired product 2b (2.42 g, 78%). ¹H NMR (300 MHz,

CDCl₃): δ=7.76 (s, 1H), 7.42 (d, J=6.9 Hz, 2H), 7.01 (d, J=6.9

Hz, 2H), 5.19 (br s, 2H), 4.30 (q, J=7.1 Hz, 2H), 3.82 (s, 3H),

1.36 (t, J=7.1 Hz, 3H) ppm; MS (ESI): m/z: 262 [M+H⁺].

4. Experimental section

4.1. General

Ethyl 5-amino-1-(p-tolyl)-1H-pyrazole-4-carboxylate (2c):

The procedure for 2b was applied to ethyl 2-cyano-3-

ethoxyacrylate (3.00 g, 17.7 mmol) and p-tolyl hydrazine

hydrochloride (2.81 g, 17.7 mmol). Silica gel column

chromatography (a mixture of n-hexane and ethyl acetate (2:1))

Triethylamine was purchased from Junsei. Lithium hydroxide

monohydrate was purchased from Fluka. Potassium iodide was

purchased from Oriental Chemical Industries. Potassium

carbonate was purchased from Duksan Pure Chemical. Merrifield

resin was purchased from Bead Tech. Trifluoroacetic acid was

purchased from Daejung Chemicals. Sodium chloridee and

sodium carbonate anhydrous were purchased from Samchun

Chemicals. p-Tolyl hydrazine hydrochloride, 4-fluorophenyl

1

gave the desired product 2c (3.69 g, 85 %). H NMR (300 MHz,

CDCl₃): δ=7.77 (s, 1H), 7.40 (d, J=8.0 Hz, 2H), 7.30 (d, J=8.0

Hz, 2H), 5.25 (br s, 2H), 4.30 (q, J=7.1 Hz, 2H), 2.41 (s, 3H),

1.36 (t, J=7.1 Hz, 3H) ppm; MS (ESI): m/z: 246 [M+H⁺].

hydrazine

hydrochloride,

(benzotriazol-1-

hexafluorophosphate,

2-(2-

yloxy)tris(dimethylamino)phosphonium

3H-1,2,3-triazolo[4,5-b]pyridin-3-ol,

Ethyl 5-amino-1-(4-fluorophenyl)-1H-pyrazole-4-carboxylate

(2d): The procedure for 2b was applied to ethyl 2-cyano-3-

ethoxyacrylate (3.00 g, 17.7 mmol) and 4-fluorophenyl hydrazine

hydrochloride (2.88 g, 17.7 mmol). Silica gel column

chromatography (a mixture of n-hexane and ethyl acetate (2:1))

methoxyphenyl)ethylamine, 4-(2-aminoethyl)morpholine and 1-

ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride

were purchased from Tokyo Chemical Industry. Benzylamine

and sodium triacetoxyborohydride were purchased from Acros

Organics. The rest of reagents used were purchased from Sigma-

Aldrich. All reagents were used without further purification.

1

gave the desired product 2d (2.89 g, 65%). H NMR (300 MHz,

CDCl₃): δ=7.78 (s, 1H), 7.52 (m, 2H), 7.20 (m, 2H), 5.25 (br s,

6

Tetrahedron

2H), 4.30 (q, J=7.1 Hz, 2H), 1.36 (t, J=7.1 Hz, 3H) ppm; MS

column chromatography (a mixture of methylene chloride and

ACCEPTED MANUSCRIPT

(ESI): m/z: 250 [M+H⁺].

ethyl acetate (7:1)) gave the desired product 3d (2.45 g, 71%).

o 1

m.p. 247.5 C; H NMR (300 MHz, DMSO-d₆): δ=12.86 (br s,

1H), 8.43 (s, 1H), 8.03 (dd, J=4.9, 9.1 Hz, 2H), 7.44 (m, 2H),

3.93 (s, 3H) ppm; ¹³C NMR (125 MHz, DMSO-d₆): δ=161.4 (d,

J=230.1 Hz), 157.5, 151.3, 149.4, 146.8, 136.7, 134.8, 124.7 (d,

J=8.6 Hz), 116.7 (d, J=23.1 Hz), 108.8, 54.2 ppm; IR (ATR,

neat): ν=3066, 2953, 1735, 1677, 1577, 1507, 1448, 1401, 1304,

1215, 1159, 1147, 1110, 1178, 1007, 968, 884, 837, 776, 686 cm^-

¹; MS (ESI): m/z: 289 [M+H⁺]; HRMS (EI): m/z calcd for

C₁₃H₉FN₄O₃: 288.0659 [M⁺]; found: 288.0658.

Ethyl 5-amino-1-(4-cyanophenyl)-1H-pyrazole-4-carboxylate

(2e): The procedure for 2b was applied to ethyl 2-cyano-3-

ethoxyacrylate (3.00 g, 17.7 mmol) and 4-cyanophenyl hydrazine

hydrochloride (3.01 g, 17.7 mmol). Silica gel column

chromatography (a mixture of n-hexane and ethyl acetate (1:1))

1

gave the desired product 2e (3.64 g, 80%). H NMR (300 MHz,

DMSO-d₆): δ=8.01 (d, J=6.9 Hz, 2H), 7.80 (d, J=6.9 Hz, 2H),

7.78 (s, 1H), 6.60 (br s, 2H), 4.23 (q, J=7.1 Hz, 2H), 1.27 (t,

J=7.1 Hz, 3H) ppm; MS (ESI): m/z: 257 [M+H⁺].

Methyl

1-(4-cyanophenyl)-4,5-dihydro-1H-pyrazolo[3,4-

Methyl 1-phenyl-4,5-dihydro-1H-pyrazolo[3,4-d]pyrimidin-4-

one-6-carboxylate (3a): To ethyl 5-amino-1-phenyl-1H-

pyrazole-4-carboxylate (2a, 1.60 g, 6.92 mmol) in 4N HCl in 1,4-

dioxane (35 mL) at room temperature was added methyl

cyanoformate (1.77 g, 20.8 mmol). The mixture was stirred at

100 °C for 14 h and was cooled to room temperature. After 1,4-

dioxane was removed in vacuo and the residue was partitioned

between methylene chloride and water. The organic layer was

dried over magnesium sulfate and was evaporated in vacuo. The

residue was chromatographed on a silica gel column with a

mixture of methylene chloride and ethyl acetate (7:1) to give the

desired product 3a (1.47 g, 78%). m.p. 235.9 C; H NMR (300

MHz, CDCl₃): δ=10.40 (br s, 1H), 8.35 (s, 1H), 8.06 (d, J= 7.7Hz,

2H), 7.55 (t, J= 7.5 Hz, 2H), 7.40 (t, J=7.5 Hz, 1H), 4.09 (s, 3H)

ppm; ¹³C NMR (125 MHz, CDCl₃): δ=160.6, 157.1, 150.9, 144.1,

138.2, 136.4, 129.3, 127.8, 122.3, 108.9, 54.5 ppm; IR (ATR,

neat): ν=3071, 2943, 1732, 1670, 1597, 1576, 1508, 1492, 1444,

1399, 1294, 1205, 1114, 1111, 1093, 1007, 967, 869, 778, 688

cm^-1; MS (ESI): m/z: 271 [M+H⁺]; HRMS (EI): m/z calcd for

C₁₃H₁₀N₄O₃: 270.0753 [M⁺]; found: 270.0753.

d]pyrimidin-4-one-6-carboxylate (3e): The procedure for 3a

was applied to ethyl 5-amino-1-(4-cyanophenyl)-1H-pyrazole-4-

carboxylate (2e, 3.50 g, 13.658 mmol). Silica gel column

chromatography (a mixture of methylene chloride and ethyl

acetate (6:1)) gave the desired product 3e (3.58 g, 88%). m.p.

o

1

280.7 C; H NMR (300 MHz, DMSO-d₆): δ=13.03 (br s, 1H),

8.52 (s, 1H), 8.34 (d, J=8.8 Hz, 2H), 8.09 (d, J=8.8 Hz, 2H), 3.96

(s, 3H) ppm; ¹³C NMR (125 MHz, DMSO-d₆): δ=160.5, 157.2,

152.5, 149.6, 147.8, 142.1, 137.6, 134.1, 122.6, 118.5, 110.1,

54.0 ppm; IR (ATR, neat): ν= 3055, 1752, 1692, 1604, 1579,

1509, 1438, 1397, 1303, 997, 879, 835, 774, 738, 674, 584, 548

cm^-1; MS (ESI): m/z: 296 [M+H⁺]; HRMS (EI): m/z calcd for

C₁₄H₉N₅O₃: 295.0705 [M⁺]; found: 295.0706.

o

1

1-Phenyl-4,5-dihydro-1H-pyrazolo[3,4-d]pyrimidin-4-one-6-

carboxylic acid (4a): To methyl 1-phenyl-4,5-dihydro-1H-

pyrazolo[3,4-d]pyrimidin-4-one-6-carboxylate (3a, 2.30 g, 8.51

mmol) in MeOH/water (75 mL/75 mL) at room temperature was

added lithium hydroxide monohydrate (893 mg, 21.3 mmol) and

the mixture was stirred for 3.5 h at the same temperature. After

completion of the reaction, the reaction mixture was adjusted to

pH 3-4 by adding 1N hydrochloric acid. The precipitated solid

was filtered and washed with water to give the desired product 4a

(1.96 g, 90%). m.p. 326.3 C; H NMR (300 MHz, DMSO-d₆):

δ=12.59 (br s, 1H), 8.41 (s, 1H), 8.06 (d, J=7.6 Hz, 2H), 7.60 (t,

J=7.6 Hz, 2H), 7.44 (t, J=7.6 Hz, 1H) ppm; ¹³C NMR (125 MHz,

DMSO-d₆): δ= 161.6, 157.7, 151.6, 148.3, 138.7, 136.6, 129.7,

127.6, 122.4, 108.8 ppm; IR (ATR, neat): ν=3119, 1717, 1635,

1586, 1560, 1540, 1498, 1473, 1459, 1425, 1389, 1337, 1306,

1285, 1198, 1063, 1024, 999, 963, 837, 820, 775, 757, 682 cm^-1;

MS (ESI): m/z: 257 [M+H⁺]; HRMS (EI): m/z calcd for

C₁₂H₈N₄O₃: 256.0596 [M⁺]; found: 256.0594.

Methyl

1-(4-methoxyphenyl)-4,5-dihydro-1H-pyrazolo[3,4-

d]pyrimidin-4-one-6-carboxylate (3b): The procedure for 3a

was applied to ethyl 5-amino-1-(4-methoxyphenyl)-1H-pyrazole-

4-carboxylate (2b, 2.36 g, 9.03 mmol). Silica gel column

chromatography (a mixture of methylene chloride and ethyl

acetate (7:1)) gave the desired product 3b (1.97 g, 72%). m.p.

o

1

o

1

184.7 C; H NMR (300 MHz, CDCl₃): δ=10.01 (br s, 1H), 8.31

(s, 1H), 7.92 (d, J=8.9 Hz, 2H), 7.05 (d, J=8.9 Hz, 2H), 4.07 (s,

3H), 3.87 (s, 3H) ppm; ¹³C NMR (125 MHz, CDCl₃): δ= 160.6,

159.1, 157.2, 150.5, 144.0, 136.0, 131.3, 123.9, 114.4, 108.5,

55.6, 54.4 ppm; IR (ATR, neat): ν=3383, 3236, 2959, 1734,1708,

1678, 1578, 1535, 1511, 1443, 1431, 1305, 1256, 1206, 1084,

972, 830, 774, 659 cm^-1; MS (ESI): m/z: 301 [M+H⁺]; HRMS

(EI): m/z calcd for C₁₄H₁₂N₄O₄: 300.0859 [M⁺]; found: 300.0828.

1-(4-Methoxyphenyl)-4,5-dihydro-1H-pyrazolo[3,4-

d]pyrimidin-4-one-6-carboxylic acid (4b): The procedure for

4a was applied to methyl 1-(4-methoxyphenyl)-4,5-dihydro-1H-

pyrazolo[3,4-d]pyrimidin-4-one-6-carboxylate (3b, 1.91 g, 6.37

mmol) to give the desired product 4b (1.48 g, 81%). m.p. 301.3

Methyl 1-(p-tolyl)-4,5-dihydro-1H-pyrazolo[3,4-d]pyrimidin-

4-one-6-carboxylate (3c): The procedure for 3a was applied to

ethyl 5-amino-1-(p-tolyl)-1H-pyrazole-4-carboxylate (2c, 2.90 g,

11.8 mmol ). Silica gel column chromatography (a mixture of n-

hexane and ethyl acetate (2:1)) gave the desired product 3c (1.43

g, 43%). m.p. > 375 ^oC; ¹H NMR (300 MHz, DMSO-d₆):

δ=10.02-9.93 (br s, 1H), 8.32 (s, 1H), 7.91 (d, J=8.4 Hz, 2H),

7.34 (d, J=8.4 Hz, 2H), 4.08 (s, 3H), 2.42 (s, 3H) ppm; ¹³C NMR

(125 MHz, CDCl₃): δ=160.6, 156.8, 150.6, 143.8, 137.9, 136.2,

135.6, 129.9, 122.3, 108.7, 54.5, 21.1 ppm; IR (ATR, neat):

ν=3355, 3267, 2957, 1758, 1742, 1674, 1577, 1534, 1509, 1428,

1400, 1288, 1212, 1150, 1123, 1081, 1002, 968, 891, 810, 774,

677 cm^-1; MS (ESI): m/z: 285 [M+H⁺]; HRMS (EI): m/z calcd for

C₁₄H₁₂N₄O₃: 284.0909 [M⁺]; found: 284.0904.

1

^oC; H NMR (300 MHz, DMSO-d₆): δ=12.51 (br s, 1H), 8.36 (s,

1H), 7.90 (d, J=9.1 Hz, 2H), 7.14 (d, J=9.1 Hz, 2H), 3.83 (s, 4H)

ppm; ¹³C NMR (125 MHz, DMSO-d₆): δ= 161.6, 158.9, 157.5,

151.1, 147.9, 136.2, 131.6, 124.2, 114.9, 108.4, 55.9 ppm; IR

(ATR, neat): ν= 3288, 3116, 3014, 2837, 1694, 1636, 1578, 1540,

1509, 1443, 1301, 1275, 1244, 1198, 1183, 1024, 993, 964, 819,

774, 692, 667 cm^-1; MS (ESI): m/z: 287 [M+H⁺]; HRMS (EI):

m/z calcd for C₁₃H₁₀N₄O₄: 286.0702 [M⁺]; found: 286.0753.

1-(p-Tolyl)-4,5-dihydro-1H-pyrazolo[3,4-d]pyrimidin-4-one-

6-carboxylic acid (4c): The procedure for 4a was applied to

methyl 1-(p-tolyl)-4,5-dihydro-1H-pyrazolo[3,4-d]pyrimidin-4-

one-6-carboxylate (3c, 1.39 g, 4.89 mmol) to give the desired

product 4c (1.19 g, 90%). m.p. 301.3 C; H NMR (300 MHz,

DMSO-d₆): δ=12.56 (br s, 1H), 8.39 (s, 1H), 7.90 (d, J= 8.3 Hz,

2H), 7.39 (d, J= 8.3 Hz, 2H), 2.39 (s, 3H) ppm; ¹³C NMR (125

MHz, DMSO-d₆): δ=161.4, 157.5, 151.2, 147.7, 137.4, 136.2,

Methyl

1-(4-fluorophenyl)-4,5-dihydro-1H-pyrazolo[3,4-

o

1

d]pyrimidin-4-one-6-carboxylate (3d): The procedure for 3a

was applied to ethyl 5-amino-1-(4-fluorophenyl)-1H-pyrazole-4-

carboxylate carboxylate (2d, 3.00 g, 12.1 mmol). Silica gel

pyrazolo[3,4-d]pyrimidin-4-one-6-carboxamide (6, 30 mg, 0.065

mmol), in DMF (3 mL) at room temperature were added

(benzotriazol-1-yloxy)tris(dimethylamino)phosphonium

135.8, 130.0, 122.3, 108.4, 20.9 ppm; IR (ATR, neat): ν=3230,

3111, 2913, 1718, 1537, 1510,1457, 1401, 1300, 1265, 1231,

1196, 1185, 1084, 1027, 997, 965, 946, 879, 827, 813, 790, 776,

671 cm^-1; MS (ESI): m/z: 271 [M+H⁺]; HRMS (EI): m/z calcd for

C₁₃H₁₀N₄O₄: 270.0753 [M⁺]; found: 270.0754.

ACCEPTED MANUSCRIPT

hexafluorophosphate (38 mg, 0.085 mmol) and N,N-

diisopropylethylamine(43 mg, 0.98 mmol). The mixture was

stirred for 15 min at room temperature and benzylamine (14 mg,

0.13 mmol) was added to the mixture. The resulting mixture was

stirred for 7 h at the same temperature. The mixture was

partitioned between methylene chloride and distilled water. The

organic layer was evaporated in vacuo and the residue was

chromatographed on a silica gel column with a mixture of n-

hexane and ethyl acetate (1:1) to give the desired product 7 (30

1-(4-Fluorophenyl)-4,5-dihydro-1H-pyrazolo[3,4-

d]pyrimidin-4-one-6-carboxylic acid (4d): The procedure for

4a was applied to methyl 1-(4-fluorophenyl)-4,5-dihydro-1H-

pyrazolo[3,4-d]pyrimidin-4-one-6-carboxylate (3d, 2.91 g, 1.10

mmol) to give the desired product 4d (2.24 g, 81%). m.p. 111.2

1

^oC; H NMR (300 MHz, DMSO-d₆): δ=12.05 (br s, 1H), 8.37 (s,

1H), 8.11 (dd, J=4.9, 9.1 Hz, 2H), 7.44 (m, 2H) ppm; ¹³C NMR

(125 MHz, DMSO-d₆): δ=165.9 (d, J= 242.9 Hz), 166.2, 162.2,

156.9, 155.4, 141.3 (d, J= 9.3 Hz), 139.8, 129.2, 121.3 (d, J=

22.8 Hz), 113.0 ppm; IR (ATR, neat): ν=3152, 3120, 3061, 1700,

1618, 1575, 1506, 1443, 1399, 1381, 1362, 1311, 1278, 1222,

1199, 1160, 1117, 1080, 1013, 997, 964, 876, 835, 805, 776, 728,

692, 673 cm^-1; MS (ESI): m/z: 275 [M+H⁺]; HRMS (EI): m/z

calcd for C₁₂H₇FN₄O₃: 274.0502 [M⁺]; found: 274.0502.

o

1

mg, 84%). m.p. 235.8 C; H NMR (300 MHz, CDCl₃): δ=8.23

and 8.10 (2d, J= 8.3 Hz, 0.6H and 1.4H), 8.03 (m, 1H), 7.47-7.35

(m, 2H), 7.32- 7.27 (m, 3H), 7.26-7.23 (m, 3H), 6.46, 6.36 and

6.33 (m,3H), 4.75 (m, 2H), 4.35 (m, 2H), 3.82, 3.80, 3.72 and

3.66 (4s, 6H), 3.28 and 2.91 (2d, J= 7.6 Hz, 1.3H and 0.7H), 2.16

and 1.91 (2m, 0.7H and 0.3H), 1.0 and 0.72 (2d, J= 6.6 Hz, 4H

and 2H) ppm; ¹³C NMR (125 MHz, CDCl₃): δ=168.9, 161.1,

160.2, 160.1, 158.6, 158.1, 138.8,137.6, 129.7, 128.9, 128.8,

128.7, 127.8, 127.7, 127.3, 126.2, 121.3, 117.2, 104.3, 104.1,

98.3, 55.3, 51.0, 46.3, 42.2, 41.9, 29.7, 26.7, 20.1 ppm; IR (ATR,

neat): ν=3265, 2956, 2925, 2870, 1683, 1625, 1610, 1597, 1585,

1560, 1502, 1451, 1419, 1345, 1308, 1288, 1285, 1204, 1155,

1031, 958, 917, 838, 801, 755, 509, 682 cm^-1; MS (ESI): m/z: 551

[M+H⁺]; HRMS (EI): m/z calcd for C₃₂H₃₄N₆O₃: 550.2692 [M⁺];

found: 550.2686.

1-(4-Cyanophenyl)-4,5-dihydro-1H-pyrazolo[3,4-d]pyrimidin-

4-one-6-carboxylic acid (4e): The procedure for 4a was applied

to

methyl

1-(4-cyanophenyl)-4,5-dihydro-1H-pyrazolo[3,4-

d]pyrimidin-4-one-6-carboxylate (3e, 3.10 g, 10.4 mmol) to give

1

the desired product 4e (2.65 g, 90%). m.p. >375^oC; H NMR

(300 MHz, DMSO-d₆): δ=12.62 (br s, 1H), 8.49 (s, 1H), 8.40 (d,

J= 8.8 Hz, 2H), 8.08 (d, J= 8.8 Hz, 2H) ppm; ¹³C NMR (125

MHz, DMSO-d₆): δ=161.4, 157.3, 152.5, 149.0, 142.0, 137.8,

134.1, 121.7, 121.4, 118.8, 109.5 ppm; IR (ATR, neat): ν= 3102,

3009, 2226, 1707, 1606, 1574, 1537, 1502, 1429, 1397, 1258,

1210, 1186, 1077, 1021, 990, 955, 927, 845, 832, 816, 774, 710,

679 cm^-1; MS (ESI): m/z: 282 [M+H⁺]; HRMS (EI): m/z calcd for

C₁₃H₇N₅O₃: 281.0549 [M⁺]; found: 281.0550.

4-Benzylamino-N-isobutyl-1-phenyl-1H-pyrazolo[3,4-

d]pyrimidine-6-carboxamide (8a): To 4-benzylamino-N-(2,4-

dimethoxybenzyl)-N-isobutyl-1-phenyl-1H-pyrazolo[3,4-

d]pyrimidine-6-carboxamide (50 mg, 0.091 mmol) in methylene

chloride (3 mL) at room temperature was added TFA (1 mL) and

the reaction mixture was stirred for 3 h. The mixture was

evaporated in vacuo, was treated with an excess amount of

triethylamine in methylene chloride, and was adsorbed on a

suitable amount of silica gel. The adsorbate was

chromatographed on a silica gel column with a mixture of n-

hexane and ethyl acetate (1:2) to give the desired product 8a (33

N-(2,4-Dimethoxybenzyl)-N-isobutyl-1-phenyl-4,5-dihydro-

1H-pyrazolo[3,4-d]pyrimidin-4-one-6-carboxamide (6): To 1-

phenyl-4,5-dihydro-1H-pyrazolo[3,4-d]pyrimidin-4-one-6-

carboxylic acid (4a, 650 mg, 0.254 mmol), 3H-1,2,3-triazolo[4,5-

b]pyridin-3-ol

(38

mg,

0.28

mmol)

and

1-(3-

o

1

mg, 91%). m.p. 158.4 C; H NMR (300 MHz, CDCl₃): δ=8.15

(m, 2H), 8.04 (m, 1H), 7.50 (m, 2H), 7.39-7.31 (m, 6H), 6.34 (br,

1H), 4.91 (d, J=5.7 Hz, 2H), 3.32 (t, J=6.6 Hz, 2H), 1.96-1.87 (m,

1H), 0.98 (d, J=6.7 Hz, 6H) ppm; ¹³C NMR (125 MHz, DMSO-

d₆)): δ=163.5, 157.0, 156.7, 153.9, 139.5, 139.2, 134.3, 129.6,

128.9, 128.3, 127.6, 126.9, 121.4, 102.3, 46.9, 44.1, 28.6, 20.5

ppm; IR (ATR, neat): ν=3499, 3363, 3265, 3205, 3111, 3050,

2954, 2923, 2866, 1659, 1619, 1595, 1561, 1528, 1496, 1452,

1414, 1381, 1350, 1312, 1293, 1263, 1218, 1183, 1139, 1109,

1098, 960, 912, 897, 878, 755, 731, 698 cm^-1; MS (ESI): m/z: 401

[M+H⁺]; HRMS (EI): m/z calcd for C₂₃H₂₄N₆O: 400.2012 [M⁺];

found: 400.2007.

Resin 9a (R¹= isobutyl): To AMEBA resin (200 mg,

theoretically 0.221 mmol) in 1,2-dichloroethane (5 mL) at room

temperature were added isobutylamine (49 mg, 0.66 mmol) and

sodium triacetoxyborohydride (141 mg, 0.663 mmol). The

resulting mixture was shaked for 21 h at the same temperature.

The resin was filtered and washed with MC (3×10 mL), DMF

(3×10 mL), MeOH (3×10 mL), H₂O (3×10 mL), MeOH (3×10

mL), DMF (3×10 mL) and MC (3×10 mL). Drying the resin in a

vacuum oven gave the desired resin 9a (161 mg). IR (ATR,

neat): ν=3024, 2919, 1603, 1492, 1451, 1419, 1373, 1267, 1195,

1158, 1029, 822, 756, 697 cm^-1.

dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (79

mg, 0.51 mmol) in DMF (2 mL) at room temperature was added

N-(2,4-dimethoxybenzyl)-2-methylpropan-1-amine (57 mg, 0.25

mmol) in DMF (0.5 mL). The resulting mixture was stirred for 8

h at the same temperature. The mixture was partitioned between

ethyl acetate and distilled water. The organic layer was dried

over magnesium sulfate and was evaporated in vacuo. The

residue was chromatographed on a silica gel column with a

mixture of n-hexane and ethyl acetate (1:1) to give the desired

product 6 (100 mg, 85%). m.p. 119.2 C; H NMR (300 MHz,

CDCl₃): δ=10.37 and 10.14 (2 br s, 0.3 H and 0.7 H), 8.30(s, 1H),

7.89-7.84 (m, 2H), 7.50 (m, 1H), 7.41-7.33 (m, 2H), 7.22 and

7.01 (2d, J= 8.1 Hz, 0.3 H and 0.7 H), 6.47-6.41 (m, 2H), 5.17

and 4.74 (2s, 1.4 H and 0.6 H), 3.93 and 3.28 (2d, J= 7.3 Hz, 0.7

H and 1.3 H), 3.82, 3.78 and 3.68 (3s, 6H), 2.14 and 2.04 (2m,

0.7 H and 0.3 H), 0.96 and 0.80 (2d, J= 6.5 Hz, 4H and 2H)

ppm ; ¹³C NMR (125 MHz, CDCl₃): δ=161.6, 160.8, 158.6, 157.2,

150.8, 149.2, 138.2, 136.4, 130.7, 129.2, 127.8, 127.2, 122.9,

122.0, 116.5, 108.1, 104.2, 98.7, 55.4, 54.8, 53.6, 48.1, 45.8, 27.7,

16.6, 20.2 ppm; IR (ATR, neat): ν=3126, 2961, 2935, 1718, 1632,

1573, 1499, 1459, 1437, 1396, 1289, 1252, 1201, 1154, 1118,

1031, 958, 916, 834, 796, 789, 687 cm^-1;MS (ESI): m/z: 462

[M+H⁺]; HRMS (EI): m/z calcd for C₂₅H₂₇N₅O₄: 461.2063 [M⁺];

found: 461.2063.

o

1

Resin 10a (Ar = C₆H₅, R¹= isobutyl): To resin 9a (130 mg,

theoretically 0.135 mmol) in DMF (1 mL) at room temperature

were added 1-phenyl-4,5-dihydro-1H-pyrazolo[3,4-d]pyrimidin-

4-one-6-carboxylic acid (4a, 69 mg, 0.27 mmol), 3H-1,2,3-

4-Benzylamino-N-(2,4-dimethoxybenzyl)-N-isobutyl-1-

phenyl-1H-pyrazolo[3,4-d]pyrimidine-6-carboxamide (7): To

N-(2,4-dimethoxybenzyl)-N-isobutyl-1-phenyl-4,5-dihydro-1H-

8

Tetrahedron

ACCEPTED MANUSCRIPT

triazolo[4,5-b]pyridin-3-ol (37 mg, 0.27 mmol) and 1-(3-

(155 mg, theoretically 0.128 mmol) using benzylamine (41 mg,

dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (46

mg, 0.30 mmol) in DMF (3 mL). The resulting mixture was

shaked for 19 h at the same temperature. The resin was filtered

and washed with DMF (3×10 mL), MC (3×10 mL) DMF (3×10

mL) and MC (3×10 mL). Drying the resin in a vacuum oven gave

the desired resin 10a (161 mg). IR (ATR, neat): ν=3025, 2920,

1707, 1685, 1636, 1585, 1559, 1540, 1506, 1492, 1450, 1420,

1287, 1263, 1196, 1159, 1111, 1028, 972, 907, 819, 757, 735,

637 cm^-1.

Resin 10b (Ar = 4-MeO-C₆H₄, R¹= isobutyl): The procedure for

10a was applied to resin 9a (170 mg, theoretically 0.177 mmol)

using

d]pyrimidin-4-one-6-carboxylic acid (4b, 478 mg, 1.58 mmol) to

give the desired resin 10b (182 mg). IR (ATR, neat): ν=3024,

2921, 1707, 1653, 1636, 1604, 1559, 1541, 1508, 1491, 1449,

1419, 1288, 1248, 1195, 1158, 1113, 1082, 1029, 974, 830, 756,

696 cm^-1.

Resin 10c (Ar = 4-Me-C₆H₄, R¹= isobutyl): The procedure for

10a was applied to resin 9a (170 mg, theoretically 0.177 mmol)

0.38 mmol) to give the desired resin 11c (161 mg). IR (ATR,

neat): ν=3023, 2921, 1602, 1586, 1560, 1507, 1492, 1450, 1340,

1285, 1195, 1157, 1115, 1028, 956, 817, 755, 696 cm^-1.

Resin 11d (Ar

= = =

4-F-C₆H₄, R¹isobutyl, NR²R³

benzylamino): The procedure for 11a was applied to resin 10d

(155 mg, theoretically 0.127 mmol) using benzylamine (41 mg,

0.38 mmol) to give the desired resin 11d (122 mg). IR (ATR,

neat): ν=3023, 2919, 1644, 1601, 1567, 1508, 1492, 1450, 1286,

1195, 1155, 1110, 956, 834, 755, 696 cm^-1.

Resin 11e (Ar = 4-NC-C₆H₄, R¹= isobutyl, NR²R³

=

benzylamino): The procedure for 11a was applied to resin 10e

(100 mg, theoretically 0.0659 mmol) using benzylamine (42 mg,

0.39 mmol) to give the desired resin 11e (102 mg). IR (ATR,

neat): ν=3027, 2927, 1591, 1578, 1507, 1493, 1452, 1380, 1279,

1198, 1159, 1119, 1068, 1025, 951,841, 821, 752, 690 cm^-1.

1-(4-methoxyphenyl)-4,5-dihydro-1H-pyrazolo[3,4-

4-(Benzylamino)-N-isobutyl-1-phenyl-1H-pyrazolo[3,4-

d]pyrimidine-6-carboxamide (8a): To resin 11a (132 mg,

theoretically 0.103 mmol) in methylene chloride (3 mL) at room

temperature was added TFA (1 mL) and the reaction mixture was

shaked for 3 h. The mixture was filtered and washed with

methylene chloride. The filtrate was evaporated in vacuo, was

treated with an excess amount of triethylamine in methylene

chloride, and was adsorbed on a suitable amount of silica gel.

The adsorbate was chromatographed on a silica gel column with

a mixture of n-hexane and ethyl acetate (1:2) to give the desired

product 8a (29 mg, 70%).

using

1-(p-tolyl)-4,5-dihydro-1H-pyrazolo[3,4-d]pyrimidin-4-

one-6-carboxylic acid (4c, 96 mg, 0.35 mmol) to give the desired

resin 10c (178 mg). IR (ATR, neat): ν=2919, 1700, 1641, 1584,

1540, 1507, 1491, 1449, 1287, 1195, 1154, 1107, 834, 755, 696

cm^-1.

Resin 10d (Ar = 4-F-C₆H₄, R¹= isobutyl): The procedure for 10a

was applied to resin 9a (170 mg, theoretically 0.177 mmol) using

1–(4-fluorophenyl)-4,5-dihydro-1H-pyrazolo[3,4-d]pyrimidin-4-

one-6-carboxylic acid (4d, 97 mg, 0.35 mmol) to give the desired

resin 10d (183 mg). IR (ATR, neat): ν=3022, 2920, 1709, 1646,

1606, 1583, 1507, 1491, 1449, 1286, 1195, 1158, 1113, 1028,

838, 757, 696 cm^-1.

Resin 10e (Ar = 4-NC-C₆H₄, R¹= isobutyl): The procedure for

10a was applied to resin 9a (170 mg, theoretically 0.177 mmol)

using

d]pyrimidin-4-one-6-carboxylic acid (4e, 100 mg, 0.35 mmol) to

give the desired resin 10e (192 mg). IR (ATR, neat): ν=3022,

2919, 1701, 1649, 1584, 1507, 1491, 1450, 1287, 1196, 1158,

1113, 1028, 817, 753, 696 cm^-1.

Resin 11a (Ar = C₆H₅, R¹= isobutyl, NR²R³= benzylamino): A

mixture of resin 10a (150 mg, theoretically 0.125 mmol),

(benzotriazol-1-yloxy)tris(dimethylamino)phosphonium

4-Benzylamino-N-isobutyl-1-(4-methoxyphenyl)-1H-

pyrazolo[3,4-d]pyrimidine-6-carboxamide (8b): The procedure

for 8a was applied to resin 11b (120 mg, theoretically 0.091

mmol). Silica gel column chromatography (a mixture of

methylene chloride and ethyl acetate (5:1)) gave the desired

o

1

product 8b (28 mg, 71%). m.p. 149.3 C; H NMR (300 MHz,

CDCl₃): δ=8.15 (br s, 1H), 8.04 (t, J=5.9 Hz, 2H), 7.97 (d, J=8.7

Hz, 2H), 7.33 (m, 4H), 6.96 (d, J=8.1 Hz, 2H), 6.76 (br s,1H),

4.86 (d, J=5.5 Hz, 2H), 3.83 (s, 3H), 3.30 (t, J=6.4 Hz, 2H), 1.90

(m, 1H), 0.97 (d, J=6.8 Hz, 6H) ppm; ¹³C NMR (125 MHz,

CDCl₃): δ=163.7, 158.0, 156.5, 155.2, 153.2, 138.5, 133.2, 132.1,

128.6, 127.5, 123.7, 114.0, 102.3, 55.4, 47.0, 45.0, 29.6, 28.5,

20.3 ppm; IR (ATR, neat): ν=3352, 3263, 2955, 2919, 2867,

1659, 1608, 1555, 1442, 1385, 1341,1299, 1251, 1211, 1175,

1138, 1087, 961, 908, 835, 812, 777, 718, 689 cm^-1; MS (ESI):

m/z: 431 [M+H⁺]; HRMS (EI): m/z calcd for C₂₄H₂₆N₆O₂:

430.2117 [M⁺]; found: 430.2119.

1-(4-cyanophenyl)-4,5-dihydro-1H-pyrazolo[3,4-

hexafluorophosphate (111 mg, 0.250 mmol) and N,N-

diisopropylethylamine (138 mg, 0.313 mmol) in DMF (3 mL)

was shaked at room temperature, followed by the addition of

benzylamine (48 mg, 0.45 mmol) after 1 h. The resulting mixture

was shaked for 13 h at the same temperature. The resin was

filtered and washed with DMF (3ⅹ5mL), MC (3ⅹ5mL) DMF

4-Benzylamino-N-isobutyl-1-(p-tolyl)-1H-pyrazolo[3,4-

d]pyrimidine-6-carboxamide (8c): The procedure for 8a was

applied to resin 11c (95 mg, theoretically 0.073 mmol). Silica gel

column chromatography (a mixture of methylene chloride and

ethyl acetate (5:1)) gave the desired product 8c (15 mg, 50%).

(3ⅹ5mL) and MC (3ⅹ10mL). Drying the resin in a vacuum

oven to give the desired resin 11a (132 mg). IR (ATR, neat):

ν=3109, 2922, 1647, 1582, 1560, 1502, 1491, 1450, 1419, 1341,

1286, 1195, 1157, 1112, 1028, 1017, 955, 818, 807, 754, 696 cm^-

m.p. 175.6 C; ¹H NMR (300 MHz, CDCl₃): δ=8.27 (br s, 1H),

o

8.07 (m, 2H), 7.97 (d, J=8.1 Hz, 3H), 7.34 (m, 2H), 7.14 (m, 3H),

6.42 (br s, 1H), 4.85 (d, J=5.5 Hz, 2H), 3.31 (q, J=6.5 Hz, 2H),

2.38 (s, 3H), 1.90 (m, 1H), 1.00 (d, J=6.8 Hz, 6H) ppm; ¹³C

NMR (125 MHz, CDCl₃): δ=163.6, 157.6, 155.3, 154.8, 153.4,

136.6, 134.3, 133.2, 129.9, 128.5, 127.5, 121.8, 102.2, 47.1, 45.0,

30.9, 28.9, 21.0, 20.2 ppm; IR (ATR, neat): ν=3379, 3251, 3024,

2956, 2867, 166, 1603, 1554, 1513, 1463, 1428, 1380, 1340,

1248, 1210, 1155, 1139, 1120, 1085, 1019 958, 934, 910, 849,

815, 778, 737, 723, 695 cm^-1; MS (ESI): m/z: 415 [M+H⁺];

HRMS (EI): m/z calcd for C₂₄H₂₆N₆O: 414.2168 [M⁺]; found:

414.2168.

1

.

Resin 11b (Ar = 4-MeO-C₆H₄, R¹= isobutyl, NR²R³

=

benzylamino): The procedure for 11a was applied to resin 10b

(160 mg, theoretically 0.130 mmol) using benzylamine (42 mg,

0.37 mmol) to give the desired resin 11b (163 mg). IR (ATR,

neat): ν=3024, 2921, 1653, 1608, 1565, 1508, 1492, 1450, 1341,

1287, 1196, 1155, 1110, 1082, 1028, 1017, 956, 834, 755, 686

cm^-1.

Resin 11c (Ar

benzylamino): The procedure for 11a was applied to resin 10c

= = =

4-Me-C₆H₄, R¹isobutyl, NR²R³

4-Benzylamino-N-isobutyl-1-(4-fluorophenyl)-1H-

pyrazolo[3,4-d]pyrimidine-6-carboxamide (8d): The procedure

for 8a was applied to resin 11d (90 mg, theoretically 0.069

ν=3022, 2917, 1602, 1586, 1507, 1491, 1449, 1418, 1373, 1259,

ACCEPTED MANUSCRIPT

mmol). Silica gel column chromatography (a mixture of

methylene chloride and ethyl acetate (3:1)) gave the desired

1235, 1194, 1154, 1027, 818, 756, 696 cm^-1.

Resin 9g (R¹= 2-(thiophen-2-yl)ethyl): The procedure for 9a was

applied to AMEBA resin (200 mg, theoretically 0.221 mmol)

using 2-thiopheneethylamine (84 mg, 0.66 mmol) to give the

desired resin 9g (182 mg). IR (ATR, neat): ν=3023, 2916, 1603,

1586, 1491, 1449, 1361, 1283, 1255, 1194, 1155, 1028, 819, 754,

695 cm^-1.

Resin 9h (R¹= 2-(pyrrolidin-1-yl)ethyl): The procedure for 9a

was applied to AMEBA resin (200 mg, theoretically 0.221

mmol) using 1-(2-aminoethyl)pyrrolidine (76 mg, 0.66 mmol) to

give the desired resin 9h (176 mg). IR (ATR, neat): ν=3023,

2919, 1602, 1586, 1491, 1450, 1419, 1368, 1283, 1194, 1154,

1208, 818, 755, 696 cm^-1.

o

product 8d (18 mg, 61%). m.p. 160.3 C; ¹H NMR (300 MHz,

CDCl₃): δ=8.34 (br s, 1H), 8.11 (m, 5H), 7.35 (t, J= 6.9 Hz, 1H),

7.15 (m, 4H), 6.47 (br s, 1H), 4.85 (d, J= 5.1 Hz, 2H), 3.33 (t, J=

6.6 Hz, 2H), 1.95 (m, 1H), 1.00 (d, J= 6.7Hz, 6H) ppm; ¹³C NMR

(125 MHz, CDCl₃): δ=163.4, 161.1 (d, J= 243.2 Hz), 158.2,

156.3, 155.6, 153.6, 135.1, 133.9, 132.9, 128.7, 127.4, 123.5 (d,

J= 7.9 Hz), 115.8 (d, J= 22.7 Hz), 102.4, 47.1, 29.7, 28.6, 20.2

ppm; IR (ATR, neat): ν=3282, 2953, 2921, 2867, 1675, 1613,

1560, 1508, 1463, 1436, 1382, 1346, 1293, 1265, 1217, 1184,

1152, 1105, 1080, 1029, 1012, 959, 903, 833, 777, 698, 670 cm^-1;

MS (ESI): m/z: 419 [M+H⁺]; HRMS (EI): m/z calcd for

C₂₃H₂₃FN₆O: 418.1917 [M⁺]; found: 418.1920.

Resin 9i (R¹= 2-(piperidin-1-yl)ethyl): The procedure for 9a was

applied to AMEBA resin (200 mg, theoretically 0.221 mmol)

using 1-(2-aminoethyl)piperidine (85 mg, 0.66 mmol) to give the

desired resin 9i (186 mg). IR (ATR, neat): ν=3022, 2919, 1605,

1586, 1504, 1491, 1450, 1282, 1194, 1155, 1133, 1028, 817, 755,

696 cm^-1.

4-Benzylamino-1-(4-cyanophenyl)-N-isobutyl-1H-

pyrazolo[3,4-d]pyrimidine-6-carboxamide (8e): The procedure

for 8a was applied to resin 11e (88 mg, theoretically 0.067

mmol). Silica gel column chromatography (a mixture of

methylene chloride and methyl alcohol (30:1)) gave the desired

o

product 8e (18 mg, 63%). m.p. 132.8 C; ¹H NMR (300 MHz,

CDCl₃): δ=8.51, (d, J= 6.7 Hz, 3H), 8.34 (d, J= 8.6 Hz, 1H), 8.11

(m, 2H), 7.76 (d, J= 8.3 Hz, 3H), 7.32 (m, 2H), 6.48 (br s, 1H),

4.87 (d, J= 5.5 Hz, 2H), 3.35 (m, 2H), 1.97 (m, 1H), 1.02 (d, J=

6.7 Hz, 6H) ppm; ¹³C NMR (125 MHz, CDCl₃): δ=163.1, 159.1,

156.0, 154.7, 142.4, 135.1, 133.2, 130.6, 128.7, 127.5, 121.1,

118.6, 109.4, 102.9, 51.5, 47.2, 29.7, 28.6, 20.3 ppm; IR (ATR,

neat): ν=3286, 2955, 2868, 2224, 1675, 1617, 1602, 1557, 1512,

1450, 1431, 1381, 1344, 1317, 1216,1184, 1126, 1115, 1086,

1028, 960, 899, 837, 773, 723, 694, 665 cm^-1; MS (ESI): m/z: 426

[M+H⁺]; HRMS (EI): m/z calcd for C₂₄H₂₃N₇O: 425.1964 [M⁺];

found: 425.1962.

Resin 9b (R¹= piperonyl): The procedure for 9a was applied to

AMEBA resin (200 mg, theoretically 0.221 mmol) using

piperonylamine (100 mg, 0.663 mmol) to give the desired resin

9b (182 mg). IR (ATR, neat): ν=3022, 2918, 1586, 1489, 1449,

1378, 1283, 1245, 1194, 1156, 1128, 1035, 928, 815, 755, 696

cm^-1.

Resin 9c (R¹= (4-methoxycarbonyl)benzyl): The procedure for

9a was applied to AMEBA resin (200 mg, theoretically 0.221

mmol) using methyl 4-(aminomethyl)benzoate hydrochloride

(134 mg, 0.663 mmol), sodium triacetoxyborohydride (141 mg,

0.663 mmol) and triethylamine (67 mg, 0.66 mmol) to give the

desired resin 9c (172 mg). IR (ATR, neat): ν=3023, 2918, 1717,

1608, 1504, 1491, 1449, 1275, 1191, 1156, 1107, 1017, 814, 752,

696 cm^-1.

Resin 9d (R¹= pyridine-4-ylmethyl): The procedure for 9a was

applied to AMEBA resin (200 mg, theoretically 0.221 mmol)

using 4-(aminomethyl)pyridine (72 mg, 0.66 mmol) to give the

desired resin 9d (174 mg). IR (ATR, neat): ν=3022, 2916, 1599,

1558, 1504, 1491, 1449, 1412, 1373, 1363, 1283, 1194, 1156,

1128, 1114, 1028, 1017, 907, 918, 754, 695, 669 cm^-1.

Resin 9j (R¹= 2-morpholinoethyl): The procedure for 9a was

applied to AMEBA resin (200 mg, theoretically 0.221 mmol)

using 4-(2-aminoethyl)morpholine (86 mg, 0.66 mmol) to give

the desired resin 9j (174 mg). IR (ATR, neat): ν=3022, 2919,

1602, 1586, 1491, 1450, 1369, 1283, 1194, 1155, 1116, 1023,

912, 820, 755, 696 cm^-1.

Resin 9k (R¹= 2-(1-methylpyrrolidin-2-yl)ethyl): The procedure

for 9a was applied to AMEBA resin (200 mg, theoretically 0.221

mmol) using 2-(2-aminoethyl)-1-methylpyrrolidine (85 mg, 0.66

mmol) to give the desired resin 9k (181 mg). IR (ATR, neat):

ν=3023, 2918, 1602, 1586, 1505, 1491, 1450, 1419, 1368, 1283,

1194, 1155, 1130, 1028, 819, 755, 696 cm^-1.

Resin 10f ( ): The procedure for 10a

Ar = C₆H₅, R¹= piperonyl

was applied to resin 9b (145 mg, theoretically 0.14 mmol) using

1-phenyl-4,5-dihydro-1H-pyrazolo[3,4-d]pyrimidin-4-one-6-

carboxylic acid (4a, 38 mg, 0.28 mmol) to give the desired resin

10f (161 mg). IR (ATR, neat): ν=3022, 2920, 1710, 1644, 1589,

1541, 1500, 1490, 1448, 1420, 1286, 1242, 1195, 1158, 1111,

1032, 976, 957, 927, 817, 755, 696 cm^-1.

Resin 10g (Ar = C₆H₅, R¹= (4-methoxycarbonyl)benzyl): The

procedure for 10a was applied to resin 9c (140 mg, theoretically

0.133 mmol) using 1-phenyl-4,5-dihydro-1H-pyrazolo[3,4-

d]pyrimidin-4-one-6-carboxylic acid (4a, 60 mg, 0.266 mmol) to

give the desired resin 10g (159 mg). IR (ATR, neat): ν=3024,

2919, 1714, 1644, 1584, 1492, 1450, 1419, 1276, 1194, 1158,

1106, 1018, 976, 946, 824, 753, 696 cm^-1.

Resin 10h (Ar = 4-MeO-C₆H₄, R¹= pyridine-4-ylmethyl): The

procedure for 10a was applied to resin 9d (140 mg, theoretically

0.141 mmol) using 1-(4-methoxyphenyl)-4,5-dihydro-1H-

pyrazolo[3,4-d]pyrimidin-4-one-6-carboxylic acid (4b, 81 mg,

0.28 mmol) to give the desired resin 10h (149 mg). IR (ATR,

neat): ν=3023, 2913, 1704, 1639, 1585, 1507, 1491, 1448, 1412,

1288, 1248, 1195, 1159, 1113, 1028, 977, 829, 755, 696 cm^-1.

Resin 10i (Ar = 4-MeO-C₆H₄, R¹= 2-methoxyphenethyl): The

procedure for 10a was applied to resin 9e (140 mg, theoretically

0.135 mmol) using 1-(4-methoxyphenyl)-4,5-dihydro-1H-

pyrazolo[3,4-d]pyrimidin-4-one-6-carboxylic acid (4b, 77 mg,

0.27 mmol) to give the desired resin 12i (1.22 g). IR (ATR, neat):

ν=3023, 2918, 1709, 1636, 1584, 1508, 1491, 1449, 1287, 1244,

1194, 1157, 1113, 1028, 970, 829, 751, 696 cm^-1.

Resin 9e (R¹= 2-methoxyphenethyl): The procedure for 9a was

applied to AMEBA resin (200 mg, theoretically 0.221 mmol)

using 2-(2-methoxyphenyl)ethanamine (100 mg, 0.663 mmol) to

give the desired resin 9e (173 mg). IR (ATR, neat): ν=3023, 2921,

1602, 1587, 1507, 1491, 1450, 1418, 1374, 1259, 1235, 1194,

1154, 1028, 818, 756, 696 cm^-1.

Resin 9f (R¹= 3,4-dimethoxyphenethyl): The procedure for 9a

was applied to AMEBA resin (200 mg, theoretically 0.221

mmol) using 3,4-dimethoxyphenethylamine (120 mg, 0.663

mmol) to give the desired resin 9f (168 mg). IR (ATR, neat):

10

Tetrahedron

Resin 10j (Ar = 4-Me-C₆H₄, R¹= 3,4-dimethoxyphenethyl):

1509, 1491, 1450, 1414, 1341, 1247, 1194, 1161, 1114, 1080,

ACCEPTED MANUSCRIPT

The procedure for 10a was applied to resin 9f (136 mg,

theoretically 0.127 mmol) using 1-(p-tolyl)-4,5-dihydro-1H-

pyrazolo[3,4-d]pyrimidin-4-one-6-carboxylic acid (4c, 69 mg,

0.25 mmol) to give the desired resin 10j (138 mg). IR (ATR,

neat): ν=3022, 2919, 1706, 1639, 1584, 1508, 1491, 1449, 1419,

1261, 1236, 1195, 1156, 1027, 817, 750, 696 cm^-1.

Resin 10k (Ar = 4-Me-C₆H₄, R¹= 2-(thiophen-2-yl)ethyl): The

procedure for 10a was applied to resin 9g (142 mg, theoretically

0.140 mmol) using 1-(p-tolyl)-4,5-dihydro-1H-pyrazolo[3,4-

d]pyrimidin-4-one-6-carboxylic acid (4c, 76 mg, 0.28 mmol) to

give the desired resin 10k (151 mg). IR (ATR, neat): ν=3022,

2918, 1706, 1636, 1610, 1583, 1507, 1491, 1449, 1286, 1261,

1194, 1158, 1113, 1028, 959, 917, 756, 695 cm^-1.

1028, 977, 942, 830, 755, 696 cm^-1.

Resin 11i (Ar = 4-MeO-C₆H₄, R¹= 2-methoxyphenethyl, NR²R³

= cyclopropylamino): The procedure for 11a was applied to resin

10i (117 mg, theoretically 0.0896 mmol) using cyclopropylamine

(15 mg, 0.27 mmol) to give the desired resin 11i (108 mg). IR

(ATR, neat): ν=3023, 2917, 1641, 1584, 1560, 158, 1491, 145,

1339, 1288, 1243, 1157, 1114, 1080, 1028, 953, 829, 750, 696

cm^-1.

Resin 11j (Ar = 4-Me-C₆H₄, R¹= 3,4-dimethoxyphenethyl,

NR²R³= cyclopropylamino): The procedure for 11a was applied

to resin 10j (110 mg, theoretically 0.0833 mmol) using

cyclopropylamine (14 mg, 0.25 mmol) to give the desired resin

11j (111 mg). IR (ATR, neat): ν=3023, 2918, 1646, 1585, 1560,

158, 1491, 1449, 1419, 1340, 1260, 1235, 1194, 1154, 1121,

1027, 954, 817,755, 696 cm^-1.

Resin 10l (Ar = 4-F-C₆H₄, R¹= 2-(pyrrolidin-1-yl)ethyl): The

procedure for 10a was applied to resin 9h (140 mg, theoretically

0.140

mmol)

using

1-(4-fluorophenyl)-4,5-dihydro-1H-

Resin 11k (Ar = 4-Me-C₆H₄, R¹= 2-(thiophen-2-yl)ethyl, NR²R³

= cyclopropylamino): The procedure for 11a was applied to resin

10k (130 mg, theoretically 0.103 mmol) using cyclopropylamine

(18 mg, 0.31 mmol) to give the desired resin 11k (119 mg). IR

(ATR, neat): ν=3023, 2919, 1644, 1583, 1559, 1507, 1491, 1449,

1419, 1340, 1286, 1194, 1157, 1113, 1028, 817, 755, 695 cm^-1.

Resin 11l (Ar = 4-F-C₆H₄, R¹= 2-(pyrrolidin-1-yl)ethyl, NR²R³=

cyclopropylamino): The procedure for 11a was applied to resin

10l (130 mg, theoretically 0.103 mmol) using cyclopropylamine

(18 mg, 0.31 mmol) to give the desired resin 11l (125 mg). IR

(ATR, neat): ν=3022, 2917, 1641, 1583, 1507, 1491, 1449, 1340,

1287, 1194, 1154, 1114, 1018, 937, 834, 753, 696 cm^-1.

Resin 11m (Ar= 4-F-C₆H₄, R¹= 2-(piperidin-1-yl)ethyl, NR²R³=

cyclopropylamino): The procedure for 11a was applied to resin

10m (135 mg, theoretically 0.106 mmol) using cyclopropylamine

(18 mg, 0.31 mmol) to give the desired resin 11m (128 mg). IR

(ATR, neat): ν=3025, 2923, 1639, 1584, 1508, 1491, 1449, 1340,

1287, 1195, 1154, 1115, 1028, 834, 754, 696 cm^-1.

Resin 11n (Ar = 4-NC-C₆H₄, R¹= 2-morpholinoethyl, NR²R³=

cyclopropylamino): The procedure for 11a was applied to resin

10n (130 mg, theoretically 0.102 mmol) using cyclopropylamine

(17 mg, 0.31 mmol) to give the desired resin 11n (129 mg). IR

(ATR, neat): ν=3022, 2915, 2222, 1641, 1584, 1560, 1507, 1491,

1449, 1340, 1284, 1194, 1156, 1114, 1069, 1028, 839, 755, 696

cm^-1.

pyrazolo[3,4,-d]pyrimidin-4-one-6-carboxylic acid (4d, 77 mg,

0.27 mmol) to give the desired resin 10l (158 mg). IR (ATR,

neat): ν=3022, 2919, 2162, 1701, 1649, 1584, 1541, 1508, 1491,

1449, 1288, 1221, 1195, 1155, 118, 1028, 834, 756, 696 cm^-1.

Resin 10m (Ar= 4-F-C₆H₄, R¹= 2-(piperidin-1-yl)ethyl): The

procedure for 10a was applied to resin 9i (150 mg, theoretically

0.148

mmol)

using

1-(4-fluorophenyl)-4,5-dihydro-1H-

pyrazolo[3,4,-d]pyrimidin-4-one-6-carboxylic acid (4d, 81 mg,

0.30 mmol) to give the desired resin 10m (161 mg). IR (ATR,

neat): ν=3023, 2921, 1697, 1644, 1584, 1508, 1491, 1450, 1289,

1222, 1196, 1155, 1109, 1028, 834, 755, 696 cm^-1.

Resin 10n (Ar = 4-NC-C₆H₄, R¹= 2-morpholinoethyl): The

procedure for 10a was applied to resin 9j (140 mg, theoretically

0.138

mmol)

using

1-(4-cyanophenyl)-4,5-dihydro-1H-

pyrazolo[3,4-d]pyrimidin-4-one-6-carboxylic acid (4e, 72 mg,

0.28 mmol) to give the desired resin 10n (157 mg). IR (ATR,

neat): ν=3022, 2920, 2225, 1702, 1649, 1606, 1583, 1507, 1492,

1450, 1430, 1395, 1286, 1196, 1158, 1114, 1028, 970, 907, 834,

757, 696 cm^-1.

Resin 10o (Ar = 4-NC-C₆H₄, R¹= 2-(1-methylpyrrolidin-2-

yl)ethyl): The procedure for 10a was applied to resin 9k (145 mg,

theoretically 0.143 mmol) using 1-(4-cyanophenyl)-4,5-dihydro-

1H-pyrazolo[3,4-d]pyrimidin-4-one-6-carboxylic acid (4e, 80

mg, 0.29 mmol) to give the desired resin 10o (136 mg). IR (ATR,

neat): ν=3022, 2917, 2225, 1701, 1639, 1605, 1584, 1507, 1491,

1449, 1431, 1286, 1196, 1158, 1114, 1028, 961, 837, 756, 696

cm^-1.

Resin 11o (Ar = 4-NC-C₆H₄, R¹= 2-(1-methylpyrrolidin-2-

yl)ethyl, NR²R³= cyclopropylamino): The procedure for 11a was

applied to resin 10o (130 mg, theoretically 0.102 mmol) using

cyclopropylamine (17 mg, 0.31 mmol) to give the desired resin

11o (128 mg). IR (ATR, neat): ν=3022, 2922, 2225, 1600, 1586,

1507, 1491, 1449, 1343, 1280, 1195, 1157, 1114, 1023, 937, 838,

755, 696 cm^-1.

Resin 11f (Ar

=

C₆H₅, R¹

=

piperonyl, NR²R³

=

cyclopropylamino): The procedure for 11a was applied to resin

10f (130 mg, theoretically 0.102 mmol) using cyclopropylamine

(18 mg, 0.31 mmol) to give the desired resin 11f (112 mg). IR

(ATR, neat): ν=3022, 2919, 1583, 1560, 1500, 1489, 1448, 1420,

134, 1242, 1194, 1157, 1114, 1031, 927, 805, 754, 696 cm^-1.

Resin 11g (Ar = C₆H₅, R¹= (4-methoxycarbonyl)benzyl, NR²R³

= cyclopropylamino): The procedure for 11a was applied to resin

10g (130 mg, theoretically 0.101 mmol) using cyclopropylamine

(17 mg, 0.30 mmol) to give the desired resin 11g (117 mg). IR

(ATR, neat): ν=3022, 2923, 1718, 1591, 1560, 1502, 1491, 1450,

1419, 1347, 1276, 1194, 1159, 1107, 1018, 945, 754, 696 cm^-1.

Resin 11h (Ar = 4-MeO-C₆H₄, R¹= pyridine-4-ylmethyl, NR²R³

= cyclopropylamino): The procedure for 11a was applied to resin

10h (120 mg, theoretically 0.0949 mmol) using

cyclopropylamine (16 mg, 0.29 mmol) to give the desired resin

11h (115 mg). IR (ATR, neat): ν=3023, 2919, 1639, 1584, 1560,

4-Cyclopropylamino-1-phenyl-N-piperonyl-1H-pyrazolo[3,4-

d]pyrimidine-6-carboxamide (8f): The procedure for 8a was

applied to resin 11f (90 mg, theoretically 0.068 mmol). Silica gel

column chromatography (a mixture of methylene chloride and

methyl alcohol (30:1)) gave the desired product 8f (21 mg, 72%).

m.p. 358.6 ^oC; ¹H NMR (300 MHz, CDCl₃): δ=8.43 (s, 1H), 8.19

(br s, 1H), 8.12 (d, J=8.0 Hz, 2H), 7.52 (t, J=7.7 Hz, 2H), 7.35 (t,

J=7.3 Hz, 1H), 6.81 (m, 3H), 6.36 (s, 1H), 5.94 (s, 2H), 4.59 (d,

J=6.1 Hz, 2H), 3.03 (m, 1H), 1.07 (d, J=6.0 Hz, 2H), 0.80 (m,

2H) ppm; ¹³C NMR (125 MHz, CDCl₃): δ=163.0, 155.2, 154.1,

147.9, 147.0, 138.7, 134.8, 132.1, 129.2, 128.8, 126.8, 121.9,

121.0, 108.4, 108.3, 101.7, 101.1, 43.6, 25.2, 9.2 ppm; IR (ATR,

neat): ν=3383, 3263, 3071, 2952, 2911, 2979,1725, 1670, 1559,

1517, 1450, 1487, 1441, 1412, 1363, 1335, 1313, 1245, 1213,

1190, 1130, 1103, 1093, 1034, 972, 957, 926, 860, 824, 780, 755,

3.86 (s, 3H), 3.81 (s, 3H), 3.73 (q, J=6.6 Hz, 2H), 2.87 (t, J= 6.7

Hz, 2H), 2.44 (s, 3H), 1.28 (m, 1H), 1.06 (m, 2H), 0.81 (m, 2H)

ppm; ¹³C NMR (125 MHz, CDCl₃): δ=163.1, 155.1, 153.7, 149.0,

147.7, 136.8, 136.2, 136.2, 135.2, 131.5, 129.7, 121.8, 120.7,

112.0, 111.3, 101.3, 55.9, 41.0, 35.3, 29.7, 25.2, 21.1, 9.2 ppm;

IR (ATR, neat): ν=2921, 2852, 1734, 1670, 1587, 1560, 1510,

1457, 1418, 1375, 1342, 1259, 1235, 1191, 1155, 1139, 1084,

1026, 954, 908, 879, 854, 816, 777, 763, 686, 662 cm^-1; MS

(ESI): m/z: 473 [M+H⁺]; HRMS (EI): m/z calcd for C₂₆H₂₈N₆O₃:

472.2223 [M⁺]; found: 472.2209.

ACCEPTED MANUSCRIPT

812, 685 cm^-1; MS (ESI): m/z: 429 [M+H⁺]; HRMS (EI): m/z

calcd for C₂₃H₂₀N₆O₃: 428.1597 [M⁺]; found: 428.1596.

4-Cyclopropylamino-N-((4-methoxycarbonyl)benzyl)-1-

phenyl-1H-pyrazolo[3,4-d]pyrimidine-6-carboxamide

(8g):

The procedure for 8a was applied to resin 11g (90 mg,

theoretically 0.068 mmol). Silica gel column chromatography (a

mixture of methylene chloride and methyl alcohol (30:1)) gave

o

1

the desired product 8g (23 mg, 77%). m.p. 228.3 C; H NMR

(300 MHz, CDCl₃): δ=8.44 (s, 1H), 8.31 (s, 1H), 8.12 (d, J=8.1

2H), 8.00 (d, J=8.1 Hz, 2H),7.51 (t, J=7.8 Hz, 2H), 7.43 (d, J=8.1

Hz, 2H), 7.35 (t, J=7.4 Hz, 1H), 6.38 (s, 1H), 4.75 (d, J=6.2 Hz,

2H), 3.91 (s, 3H), 1.27 (m, 1H), 1.08 (m, 2H), 0.82 (m, 2H) ppm;

¹³C NMR (125 MHz, CDCl₃): δ=166.8, 166.6, 163.2, 155.0,

154.0, 150.7, 150.2, 143.4, 138.7, 130.0, 129.2, 127.5, 127.0,

122.0, 101.9, 52.1, 43.4, 25.2, 9.3 ppm; IR (ATR, neat): ν=3305,

3118, 2999, 2949, 2098, 1704, 1664, 1586, 1572, 1540, 1501,

1460, 1418, 1405, 1363, 1343, 1295, 1280, 1225, 1195, 1177,

1114, 1093, 1062, 1031, 975, 941, 907, 749, 712, 695 cm^-1; MS

(ESI): m/z: 443 [M+H⁺]; HRMS (EI): m/z calcd for C₂₄H₂₂N₆O₃:

442.1753 [M⁺]; found: 442.1754.

4-Cyclopropylamino-N-(2-(thiophen-2-yl)ethyl)-1-(p-tolyl)-

1H-pyrazolo[3,4-d]pyrimidine-6-carboxamide

(8k):

The

procedure for 8a was applied to resin 11k (99 mg, theoretically

0.13 mmol). Silica gel column chromatography (a mixture of

methylene chloride and methyl alcohol (30:1)) gave the desired

o

1

product 8k (12 mg, 31%). m.p. 145.1 C; H NMR (300 MHz,

CDCl₃): δ=8.40 (s, 1H), 8.12 (br s, 1H), 7.93 (d, J=8.3 Hz, 2H),

7.31 (d, J=8.3 Hz, 2H), 7.18 (d, J=5.0 Hz, 1H), 6.95 (t, J=3.6 Hz,

1H), 6.90 (d, J=3.2 Hz, 1H), 6.53 (br s, 1H), 3.76 (q, J= 6.4 Hz,

2H), 3.16 (t, J=6.5 Hz, 2H), 2.44 (s, 3H), 1.28 (m, 1H), 1.06 (m,

2H), 0.82 (m, 2H) ppm; ¹³C NMR (125 MHz, CDCl₃): δ=163.1,

160.0, 155.0, 153.7, 141.4, 136.7, 136.3, 134.6, 129.7, 127.1,

125.5, 123.9, 121.9, 101.6, 41.0, 30.2, 21.1, 14.1, 9.2 ppm; IR

(ATR, neat): ν=3276, 2951, 2919, 2851, 1734, 1673, 1588, 1560,

1513, 1456, 1433, 1362, 1345, 1292, 1242, 1181, 1122, 1081,

1022, 972, 954, 870, 849, 816, 778, 691, 663 cm^-1; MS (ESI):

m/z: 419 [M+H⁺]; HRMS (EI): m/z calcd for C₂₂H₂₂N₆OS:

418.1576 [M⁺]; found: 418.0734.

4-Cyclopropylamino-1-(4-methoxyphenyl)-N-(pyridine-4-

ylmethyl)-1H-pyrazolo[3,4-d]pyrimidine-6-carboxamide (8h):

The procedure for 8a was applied to resin 11h (86 mg,

theoretically 0.066 mmol). Silica gel column chromatography (a

mixture of methylene chloride and methyl alcohol (20:1)) gave

o

1

the desired product 8h (21 mg, 76%). m.p. 118.8 C; H NMR

(300 MHz, CDCl₃): δ=8.56 (d, J=4.7 Hz, 2H), 8.41 (s, 1H), 8.34

(m, 2H), 7.95 (d, J=8.6 Hz, 2H), 7.04 (d, J=8.6 Hz, 2H), 6.39 (s,

1H), 4.70 (d, J=6.3 Hz, 2H), 3.87 (s, 3H), 3.04 (s, 1H), 1.26 (m,

1H), 1.08 (m, 2H), 0.85 (m, 2H) ppm; ¹³C NMR (125 MHz,

CDCl₃): δ=163.6, 159.8, 158.5, 154.7, 153.6, 150.0, 147.3, 134.5,

131.8, 123.7, 122.3, 114.4, 101.5, 55.6, 42.6, 25.2, 9.2 ppm; IR

(ATR, neat): ν=3269, 2923, 1734, 1672, 1586, 1560, 1509, 1455,

1440, 1413, 1342, 1299, 1244, 1171, 1112, 1084, 1024, 973, 952,

940, 828, 777, 731, 684 cm^-1; MS (ESI): m/z: 416 [M+H⁺];

HRMS (EI): m/z calcd for C₂₂H₂₁N₇O₂: 415.1757 [M⁺]; found:

415.1755.

4-Cyclopropylamino-1-(4-fluorophenyl)-N-(2-(pyrrolidin-1-

yl)ethyl)-1H-pyrazolo[3,4-d]pyrimidine-6-carboxamide (8l):

The procedure for 8a was applied to resin 11l (134 mg,

theoretically 0.103 mmol). Silica gel column chromatography (a

mixture of methylene chloride and methyl alcohol (10:1)) gave

1

the desired product 8l (19 mg, 45%). m.p. 74.6 ^oC; H NMR

(300 MHz, CDCl₃): δ=9.13-8.93 (br s, 1H), 8.40 (s, 1H), 8.20 (m,

2H), 7.20 (m, 2H), 3.84 (m, 2H), 3.50 (m, 2H), 3.25 (m, 4H),

2.99 (br s, 1H), 2.04 (m, 4H), 1.25 (m, 1H), 1.06 (m, 2H), 0.84

(m, 2H) ppm; ¹³C NMR (125 MHz, CDCl₃): δ=164.4, 163.0,

161.2 (d, J= 243.9 Hz), 157.5, 154.4, 135.0, 134.5, 123.6 (d, J=

8.4 Hz), 115.9 (d, J= 21.7 Hz), 101.7, 54.8, 31.6, 25.2, 23.3, 14.1,

9.0 ppm; IR (ATR, neat): ν=3259, 2921, 2850, 1734, 1671, 1586,

1509, 1457, 1438, 1416, 1362, 1348, 1295, 1196, 1173, 1123,

1021, 993, 975, 954, 835, 798, 777, 681, 669 cm^-1; MS (ESI):

m/z: 413 [M+H⁺]; HRMS (EI): m/z calcd for C₂₁H₂₄FN₇O:

409.2026 [M⁺]; found: 409.2026

4-Cyclopropylamino-N-(2-methoxyphenethyl)-1-(4-

methoxyphenyl)-1H-pyrazolo[3,4-d]pyrimidine-6-

carboxamide (8i): The procedure for 8a was applied to resin 11i

(73 mg, theoretically 0.056 mmol). Silica gel column

chromatography (a mixture of methylene chloride and methyl

alcohol (20:1)) gave the desired product 8i (12 mg, 51%). m.p.

o

1

147.2 C; H NMR (300 MHz, CDCl₃): δ=8.13 (s, 1H), 7.98 (d,

J=8.9 Hz, 3H), 7.52 (br s, 1H), 7.20 (t, J=7.6 Hz, 2H), 7.01 (d,

J=9.0 Hz, 2H), 6.87 (t, J=8.0 Hz, 2H), 3.88 (s, 3H), 3.77 (s, 3H),

3.72 (t, J=6.7 Hz, 2H), 2.95 (t, J=6.6 Hz, 2H), 1.66 (m, 1H), 1.25

(m, 2H), 0.85 (m, 2H) ppm; ¹³C NMR (125 MHz, CDCl₃):

δ=163.1, 159.8, 158.3, 157.6, 155.4, 153.6, 134.4, 132.0, 130.6,

127.8, 127.4, 123.5, 120.5, 114.3, 110.3, 101.4, 55.6, 39.7, 34.5,

30.3, 22.7, 14.9 ppm; IR (ATR, neat): ν=3267, 2922, 1734, 1670,

1610, 1586, 1560, 1509, 1458, 1438, 1379, 1342, 1299, 1241,

1171, 1118, 1085, 1027, 954, 875, 854, 829, 777, 751, 684, 660

cm^-1; MS (ESI): m/z: 459 [M+H⁺]; HRMS (EI): m/z calcd for

C₂₅H₂₆N₆O₃: 458.2066 [M⁺]; found: 458.2068.

4-Cyclopropylamino-1-(4-fluorophenyl)-N-(2-(piperidin-1-

yl)ethyl)-1H-pyrazolo[3,4-d]pyrimidine-6-carboxamide (8m):

The procedure for 8a was applied to resin 11m (135 mg,

theoretically 0.103 mmol). Silica gel column chromatography (a

mixture of methylene chloride and methyl alcohol (15:1)) gave

1

the desired product 8m (22 mg, 50%). m.p. 148.4 ^oC; H NMR

(500 MHz, CDCl₃): δ=9.07 (br s, 1H), 8.42 (s, 1H), 8.21 (m, 2H),

7.24 (t, J=8.5 Hz, 2H), 3.90 (q, J=6.0 Hz, 2H), 3.52 (s, 2H), 3.28

(m, 2H), 3.16 (q, J=7.4 Hz, 2H), 2.99 (br s, 1H), 1.89 (m, 4H),

1.35 (t, J=7.4 Hz, 2H), 1.28 (m, 1H), 1.06 (q, J=6.3 Hz, 2H), 0.91

(t, J=6.6 Hz, 2H) ppm; ¹³C NMR (125 MHz, , CDCl₃): δ=163.5,

161.1(d, J= 244.9 Hz), 157.5, 155.3, 153.9, 135.0, 134.5, 123.6

(d, J= 7.8 Hz), 115.9 (d, J= 22.6 Hz), 101.6, 56.9, 54.3, 36.4,

29.7, 25.7, 24.0, 8.9 ppm; IR (ATR, neat): ν=3248, 3092, 2947,

2863, 1670, 1587, 1509, 1455, 1437, 1418, 1365, 1347, 1296,

1278, 1196, 1177, 1126, 1034, 1011, 976, 949, 907, 886, 835,

799, 779, 718, 690, 668 cm^-1; MS (ESI): m/z: 424 [M+H⁺];

HRMS (EI): m/z calcd for C₂₂H₂₆FN₇O: 423.2183 [M⁺]; found:

423.2182

4-Cyclopropylamino-N-(3,4-dimethoxyphenethyl)-1-(p-tolyl)-

1H-pyrazolo[3,4-d]pyrimidine-6-carboxamide

(8j):

The

procedure for 8a was applied to resin 11j (75 mg, theoretically

0.055 mmol). Silica gel column chromatography (a mixture of

methylene chloride and methyl alcohol (30:1)) gave the desired

o

1

product 8j (14 mg, 55%). m.p. 81.3 C; H NMR (300 MHz,

CDCl₃): δ=8.40 (s, 1H), 7.98 (m, 1H), 7.90 (d, J=8.3 Hz, 2H),

7.29 (d, J=8.3 Hz, 2H), 6.79 (t, J=8.2 Hz, 3H), 6.79 (br s, 1H),

12

Tetrahedron

1-(4-Cyanophenyl)-4-cyclopropylamino-N-(2-

Resin 10s (Ar = 4-F-C₆H₄, R¹= cyclopropyl): The procedure for

ACCEPTED MANUSCRIPT

morpholinoethyl)-1H-pyrazolo[3,4-d]pyrimidine-6-

10a was applied to resin 9l (150 mg, theoretically 0.159 mmol)

using 1-(4-fluorophenyl)-4,5-dihydro-1H-pyrazolo[3,4-

carboxamide (8n): The procedure for 8a was applied to resin

11n (90 mg, theoretically 0.068 mmol). Silica gel column

chromatography (a mixture of methylene chloride and methyl

alcohol (20:1)) gave the desired product 8n (14 mg, 48%). m.p.

326.4 ^oC; ¹H NMR (300 MHz, CDCl₃): δ=8.54 (d, J= 8.1 Hz, 2H),

8.48 (s, 1H), 8.25 (br s, 1H), 7.82 (d, J=8.1 Hz, 2H), 6.68 (br s,

1H), 3.75 (t, J=4.5 Hz, 4H), 3.64 (q, J=5.9 Hz, 2H), 2.66 (t, J=5.5

Hz, 2H), 2.56 (t, J=4.5 Hz, 4H), 1.27 (m, 1H), 1.09 (m, 2H), 0.83

(m, 2H) ppm; ¹³C NMR (125 MHz, CDCl₃): δ=162.9, 159.7,

155.7, 142.4, 136.1, 133.2, 130.7, 121.2, 118.5, 109.6, 102.1,

67.1, 57.0, 53.8, 36.3, 25.3, 9.3 ppm; IR (ATR, neat): ν=3389,

3277, 2918, 2850, 2226, 1668, 157, 1561, 1533, 1507, 152, 1431,

1409, 1397, 1358, 1341, 1295, 1269, 1229, 1144, 1116, 1078,

1026, 976, 839, 917, 88, 865, 843, 779, 735, 698 cm^-1; MS (ESI):

m/z: 433 [M+H⁺]; HRMS (EI): m/z calcd for C₂₂H₂₄N₈O₂:

432.2022 [M⁺]; found: 432.2025.

d]pyrimidin-4-one-6-carboxylic acid (4d, 87 mg, 0.32 mmol) to

give the desired resin 10s (164 mg). IR (ATR, neat): ν=3023,

2919, 1709, 1656, 1584, 1541, 1507, 1491, 1449, 1287, 1225,

1195, 1155, 1109, 975, 833, 752, 695 cm^-1.

Resin 10t (Ar = 4-NC-C₆H₄, R¹= cyclopropyl): The procedure

for 10a was applied to resin 9l (150 mg, theoretically 0.159

mmol) using 1-(4-cyanophenyl)-4,5-dihydro-1H-pyrazolo[3,4-

d]pyrimidin-4-one-6-carboxylic acid (4e, 89 mg, 0.32 mmol) to

give the desired resin 12s (159 mg). IR (ATR, neat): ν=3022,

2918, 2846, 2222, 1706, 1653, 1605, 1583, 1541, 1506, 1491,

1449, 1429, 1407, 1394, 1277, 1194, 1157, 1113, 1027, 973, 838,

753, 695 cm^-1.

Resin 11p (Ar

= = =

C₆H₅, R¹cyclopropyl, NR²R³

piperonylamino): The procedure for 11a was applied to resin 10p

(150 mg, theoretically 0.127 mmol) using piperonylamine (57 mg,

0.38 mmol) to give the desired resin 11p (161 mg). IR (ATR,

neat): ν=3022, 2920, 1583, 1501, 1490, 1449, 1419, 1364, 1279,

1247, 1157, 1113, 977, 958, 917, 833, 812, 754, 696 cm^-1.

Resin 11q (Ar = C₆H₅, R¹= cyclopropyl, NR²R³= (pyridin-4-

ylmethyl)amino): The procedure for 11a was applied to resin 10p

1-(4-Cyanophenyl)-4-cyclopropylamino-N-(2-(1-

methylpyrrolidin-2-yl)ethyl)-1H-pyrazolo[3,4-d]pyrimidine-

6-carboxamide (8o): The procedure for 8a was applied to resin

11o (90 mg, theoretically 0.068 mmol). Silica gel column

chromatography (a mixture of methylene chloride and methyl

alcohol (15:1)) gave the desired product 8o (16 mg, 53%). m.p.

113.5 ^oC; ¹H NMR (300 MHz, CDCl₃): δ=8.54 (d, J=8.7 Hz, 2H),

8.47 (s, 1H), 7.81 (d, J=8.7 Hz, 2H), 7.04 (br s, 1H), 3.71 (m,

2H), 3.50 (t, J=4.8 Hz, 2H), 3.20 (m, 1H), 2.56 (br s, 1H), 2.44 (s,

3H), 2.03 (m, 2H), 1.81 (m, 4H), 1.26 (m, 1H), 1.09 (m, 2H),

0.87 (m, 2H) ppm; ¹³C NMR (125 MHz, CDCl₃): δ=162.9, 155.7,

142.3, 136.1, 133.3, 124.7, 121.3, 118.6, 109.6, 107.3, 102.6,

64.8, 57.0, 40.4, 37.2, 31.9, 29.7, 22.7, 14.1, 9.2 ppm; IR (ATR,

neat): ν=2951, 2926, 2780, 2223, 1724, 1670, 1618, 1585, 1509,

1448, 1431, 1408, 1345, 1272, 1178, 1115, 1077, 1022, 951, 917,

840, 814, 777, 729, 680, 662 cm^-1; MS (ESI): m/z: 431 [M+H⁺];

HRMS (EI): m/z calcd for C₂₃H₂₆N₈O: 430.2230 [M⁺]; found:

430.2227.

Resin 9l (R¹= cyclopropyl): The procedure for 9a was applied to

AMEBA (1.80 g, theoretically 1.99 mmol) using

cyclopropylamine (414 mg, 5.98 mmol) to give the desired resin

9l (1.81 g). IR (ATR, neat): ν=3022, 2918, 2846, 1609, 1586,

1502, 1491, 1450, 1419, 1369, 1283, 1263, 1194, 1155, 1128,

1028, 1017, 931, 906, 819, 756, 735, 969 cm^-1.

Resin 10p (Ar = C₆H₅, R¹= cyclopropyl): The procedure for 10a

was applied to resin 9l (160 mg, theoretically 0.169 mmol) using

1-phenyl-4,5-dihydro-1H-pyrazolo[3,4-d]pyrimidin-4-one-6-

carboxylic acid (4a, 87 mg, 0.34 mmol) to give the desired resin

10p (176 mg). IR (ATR, neat): ν=3023, 2918, 1709, 1653, 1584,

1492, 1450, 1420, 1287, 1195, 1157, 1111, 1028, 974, 754, 696

cm^-1.

(120

mg,

theoretically

0.101

mmol)

using

4-

(aminomethyl)pyridine (55 mg, 0.30 mmol) to give the desired

resin 11q (122 mg). IR (ATR, neat): ν=3022, 2921, 1654, 1582,

1560, 1502, 1491, 1450, 1418, 1363, 1344, 1260, 1194, 1157,

1113, 1027, 978, 953, 908, 830, 754, 696 cm^-1.

Resin 11r (Ar = 4-MeO-C₆H₄, R¹= cyclopropyl, NR²R³= (1-

benzylpiperidin-4-yl)amino): The procedure for 11a was applied

to resin 10q (155 mg, theoretically 0.128 mmol) using 4-amino-

1-benzylpiperidine (73 mg, 0.38 mmol) to give the desired resin

11r (166 mg). IR (ATR, neat): ν=3023, 2922, 1651, 1605, 1582,

1560, 1509, 1491, 1450, 1364, 1297, 1246, 1156, 1114, 1027,

828, 755, 696 cm^-1.

Resin 11s (Ar = 4-MeO-C₆H₄, R¹= cyclopropyl, NR²R³= (2-

(piperidin-1-yl)ethyl)amino): The procedure for 11a was applied

to resin 10q (150mg, theoretically 0.124 mmol) using 1-(2-

aminoethyl)piperidine (48 mg, 0.37 mmol) to give the desired

resin 11s (154 mg). IR (ATR, neat): ν=3024, 2921, 1654, 1582,

1560, 1510, 1492, 1450, 1364, 1342, 1298, 1246, 1178, 1157,

1115, 1080, 1027, 977, 951, 829, 755, 696 cm^-1.

Resin 11t (Ar = 4-Me-C₆H₄, R¹= cyclopropyl, NR²R³= (2-

morpholinoethyl)amino): The procedure for 11a was applied to

resin 10r (130 mg, theoretically 0.109 mmol) using 4-(2-

aminoethyl)morpholine (42 mg, 0.33 mmol) to give the desired

resin 11t (131 mg). IR (ATR, neat): ν=3024, 2919, 1656, 1601,

1582, 1560, 1491, 1449, 1194, 1157, 1115, 817, 755, 696 cm^-1.

Resin 10q (Ar = 4-MeO-C₆H₄, R¹= cyclopropyl): The procedure

for 10a was applied to resin 9l (150 mg, theoretically 0.159

mmol) using 1-(4-methoxyphenyl)-4,5-dihydro-1H-pyrazolo[3,4-

d]pyrimidin-4-one-6-carboxylic acid (4b, 91 mg, 0.32 mmol) to

give the desired resin 10q (164 mg). IR (ATR, neat): ν=3022,

2919, 1706, 1656, 1584, 1507, 1491, 1448, 1288, 1248, 1114,

1028, 975, 828, 755, 696 cm^-1.

Resin 11u (Ar = 4-Me-C₆H₄, R¹= cyclopropyl, NR²R³= (2-

(diethylamino)ethyl)(methyl)amino): The procedure for 11a was

applied to resin 10r (130 mg, theoretically 0.109 mmol) using

N,N-diethyl-N'-ethylethylenediamine (43 mg, 0.33 mmol) to give

the desired resin 11u (133 mg). IR (ATR, neat): ν=3025, 2920,

1655, 1576, 1547, 1491, 1449, 1366, 1346, 1285, 1195, 1157,

1113, 1028, 979, 950, 817, 755, 696 cm^-1.

Resin 10r (Ar = 4-Me-C₆H₄, R¹= cyclopropyl): The procedure

for 10a was applied to resin 9l (150 mg, theoretically 0.159

Resin 11v (Ar = 4-F-C₆H₄, R¹= cyclopropyl, NR²R³

=

morpholino): The procedure for 11a was applied to resin 10s

(130 mg, theoretically 0.108 mmol) using morpholine (28 mg,

0.32 mmol) to give the desired resin 11v (128 mg). IR (ATR,

neat): ν=3024, 2924, 1654, 1569, 1508, 1491, 1448, 1366, 1347,

1589, 1260, 1219, 1195, 1155, 1113, 1023, 974, 832, 755, 696

cm^-1.

mmol)

using

1-(p-tolyl)-4,5-dihydro-1H-pyrazolo[3,4-

d]pyrimidin-4-one-6-carboxylic acid (4c, 86 mg, 0.32 mmol) to

give the desired resin 10r (152 mg). IR (ATR, neat): ν=3024,

2917, 1701, 1651, 1584, 1507, 1491, 1449, 1194, 1157, 1113,

974, 817, 754, 696 cm^-1.

Resin 11w (Ar = 4-F-C₆H₄, R¹= cyclopropyl, NR²R³= 4-(2-

1H), 7.81 (d, J=8.7 Hz, 2H), 7.39 (m, 4H), 7.05 (d, J=8.7 Hz,

2H), 4.03 (br s, 1H), 3.88 (s, 3H), 3.41 (m, 2H), 3.13 (q, J= 6.9

Hz, 2H), 2.81 (m, 1H), 2.02 (m, 4H), 1.33 (t, J=7.3 Hz, 4H), 0.84

(m, 2H), 0.61 (m, 2H) ppm; ¹³C NMR (125 MHz, DMSO-d₆):

δ=165.4, 158.1, 157.4, 156.2, 153.1, 139.1, 133.7, 132.4, 129.2,

128.6, 127.4, 123.2, 114.8, 101.8, 62.6, 55.9, 52.4, 47.9, 32.0,

23.3, 6.5 ppm; IR (ATR, neat): ν=3387, 3267, 2923, 1675, 1616,

1565, 1508, 1454, 1438, 1366, 1339, 1301, 1246, 1172, 1146,

1114, 1080, 1058, 1034, 1022, 961, 940, 868, 830, 776, 740, 697,

668 cm^-1; MS (ESI): m/z: 498 [M+H⁺]; HRMS (EI): m/z calcd for

C₂₈H₃₁N₇O₂: 497.2539 [M⁺]; found: 497.2539.

ACCEPTED MANUSCRIPT

furoyl)piperazin-1-yl): The procedure for 11a was applied to

resin 10s (140 mg, theoretically 0.117 mmol) using 1-(2-

furoyl)piperazine (63 mg, 0.35 mmol) to give the desired resin

11w (152 mg). IR (ATR, neat): ν=3024, 2917, 1653, 1567, 1508,

1491, 1449, 1419, 1375, 1349, 1282, 1263, 1218, 1155, 1111,

1013, 974, 834, 750, 696 cm^-1.

Resin 11x (Ar = 4-NC-C₆H₄, R¹= cyclopropyl, NR²R³= 4-

(pyrrolidin-1-yl)piperidin-1-yl): The procedure for 11a was

applied to resin 10t (130 mg, theoretically 0.108 mmol) using 4-

(1-pyrrolidinyl)piperidine (50 mg, 0.32 mmol) to give the desired

resin 11x (121 mg). IR (ATR, neat): ν=3021, 2918, 2223, 1653,

1580, 1567, 1549, 1506, 1491, 1449, 1427, 1369, 1348, 1281,

1262, 1194, 1157, 1115, 1028, 970, 947, 838, 754, 735, 696 cm^-1.

Resin 11y (Ar = 4-NC-C₆H₄, R¹= cyclopropyl, NR²R³= 4-(3-

methoxyphenyl)piperazin-1-yl): The procedure for 11a was

applied to resin 10t (150 mg, theoretically 0.124 mmol) using 1-

(3-methoxyphenyl)piperazine (72 mg, 0.37 mmol) to give the

desired resin 11y (155 mg). IR (ATR, neat): ν=3024, 2919, 2227,

1654, 1579, 1561, 1507, 1491, 1448, 1415, 1345, 1282, 1258,

1196, 1157, 1114, 1029, 1015, 974, 945, 837, 755, 695 cm^-1.

N-Cyclopropyl-1-(4-methoxyphenyl)-4-((2-(piperidin-1-

yl)ethyl)amino)-1H-pyrazolo[3,4-d]pyrimidine-6-

carboxamide (8s): The procedure for 8a was applied to resin 11s

(130 mg, theoretically 0.0982 mmol). Silica gel column

chromatography (a mixture of methylene chloride and methyl

alcohol (10:1)) gave the desired product 8s (26 mg, 61%). m.p.

104.8 ^oC; ¹H NMR (300 MHz, CDCl₃): δ=9.63 (br s, 1H), 8.40 (s,

1H), 7.93 (d, J=2.9 Hz, 1H), 7.86 (d, J=9.0 Hz, 2H), 7.02 (d,

J=9.0 Hz, 2H), 4.05 (m, 2H), 3.87 (s, 3H), 3.39 (m, 2H), 2.89 (m,

1H), 1.92 (m, 4H), 1.71 (m, 2H), 1.26 (d, J=2.6 Hz, 2H), 0.88 (t,

J=3.8 Hz, 4H), 0.67 (m, 2H) ppm; ¹³C NMR (125 MHz, CDCl₃):

δ=164.7, 162.6, 158.4, 157.0, 154.4, 151.9, 133.8, 131.9, 123.6,

114.2, 102.4, 55.6, 53.2, 36.5, 31.6, 22.9, 14.1, 6.7 ppm; IR

(ATR, neat): ν=3266, 2953, 2923, 2852, 1733, 1670, 1618, 1561,

1512, 1457, 1441, 1363, 1348, 1300, 1246, 1197, 1171, 1123,

1084, 1026, 991, 968, 942, 828, 789, 776, 718, 664 cm^-1; MS

(ESI): m/z: 436 [M+H⁺]; HRMS (EI): m/z calcd for C₂₃H₂₉N₇O₂:

435.2383 [M⁺]; found: 435.2381.

N-Cyclopropyl-1-phenyl-4-piperonylamino-1H-pyrazolo[3,4-

d]pyrimidine-6-carboxamide (8p): The procedure for 8a was

applied to resin 11p (108 mg, theoretically 0.0713 mmol). Silica

gel column chromatography (a mixture of methylene chloride

and methyl alcohol (20:1)) gave the desired product 8p (21 mg,

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1

69%). m.p. 228.9 C; H NMR (300 MHz, CDCl₃): δ=8.12 (m,

3H), 7.95 (br s, 1H), 7.49 (t, J=7.5 Hz, 2H), 7.33 (t, J=7.2 Hz,

1H), 6.83 (d, J=7.2 Hz, 2H), 6.75 (d, J=7.8 Hz, 1H), 6.50 (br s,

1H), 5.94 (s, 2H), 4.76 (d, J=5.5 Hz, 2H), 2.91 (m, 1H), 0.89 (q,

J= 6.3 Hz, 2H), 0.65 (m, 2H) ppm; ¹³C NMR (125 MHz, DMSO-

d₆): δ=164.9, 156.9, 156.6, 153.8, 147.8, 146.8, 139.2, 134.3,

133.3, 129.7, 126.9, 122.2, 121.5, 109.0, 108.6, 102.2, 101.4,

43.9, 23.4, 6.5 ppm; IR (ATR, neat): ν=3369, 3258, 3078, 3023,

2902, 2868, 1674, 1612, 1592, 1561, 1515, 1502, 1489, 1458,

1443, 1420, 1377, 1350, 1293, 1246, 1212, 1196, 1185, 1138,

1102, 1061, 1035, 1013, 959, 927, 868, 852, 795, 777, 755, 683

cm^-1; MS (ESI): m/z: 429 [M+H⁺]; HRMS (EI): m/z calcd for

C₂₃H₂₀N₆O₃: 428.1597 [M⁺]; found: 428.1596.

N-Cyclopropyl-4-((2-morpholinoethyl)amino)-1-(p-tolyl)-1H-

pyrazolo[3,4-d]pyrimidine-6-carboxamide (8t): The procedure

for 8a was applied to resin 11t (105 mg, theoretically 0.0801

mmol). Silica gel column chromatography (a mixture of

methylene chloride and methyl alcohol (20:1)) gave the desired

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1

product 8t (16 mg, 49%). m.p. 98.3 C; H NMR (300 MHz,

CDCl₃): δ=8.14 (br s, 1H), 7.97 (m, 3H), 7.33 (d, J=8.2 Hz, 2H),

3.76 (t, J=4.4 Hz, 6H), 2.93 (m, 1H), 2.73 (t, J=6.0 Hz, 2H), 2.54

(t, J=4.4 Hz, 4H), 2.43 (s, 3H), 0.88 (m, 3H), 0.66 (m, 2H) ppm;

¹³C NMR (125 MHz, DMSO-d₆): δ=165.2, 158.9, 156.6, 136.7,

134.1, 130.1, 121.6, 118.9, 114.8, 102.4, 57.4, 46.1, 31.4, 23.5,

21.0, 14.5, 9.0 ppm; IR (ATR, neat): ν=3269, 2954, 2921, 2851,

1671, 1618, 1561, 1515, 1456, 1431, 1364, 1349, 1313, 1245,

1198, 1173, 1123, 1085, 1032, 1020, 968, 942, 855, 820, 798,

776, 719, 668 cm^-1; MS (ESI): m/z: 422 [M+H⁺]; HRMS (EI):

m/z calcd for C₂₂H₂₇N₇O₂: 421.2226 [M⁺]; found: 421.2229

N-Cyclopropyl-1-phenyl-4-((pyridine-4-ylmethyl)amino)-1H-

pyrazolo[3,4-d]pyrimidine-6-carboxamide (8q): The procedure

for 8a was applied to resin 11q (105 mg, theoretically 0.0824

mmol). Silica gel column chromatography (a mixture of

methylene chloride and methyl alcohol (20:1)) gave the desired

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1

product 8q (19 mg, 60%). m.p. 338.3 C; H NMR (300 MHz,

CDCl₃): δ=8.59 (d, J=5.6 Hz, 2H), 8.10 (m, 3H), 7.82 (br s, 1H),

7.51 (t, J=7.6 Hz, 2H), 7.34 (m, 3H), 6.58 (br s, 1H), 4.92 (d,

J=6.0 Hz, 2H), 2.87 (m, 1H), 0.88 (m, 2H), 0.62 (m, 2H) ppm;

¹³C NMR (125 MHz, CDCl₃): δ=164.8, 156.8, 154.1, 150.1,

148.9, 148.7, 139.5, 134.3, 129.7, 127.0, 123.0, 121.5, 102.3,

43.0, 23.3, 6.5 ppm; IR (ATR, neat): ν=3364, 3260, 3028, 2921,

1693, 1622, 1593, 1560, 1497, 1458, 1448, 1420, 1379, 1345,

1317, 1244, 1196, 1140, 1095, 1064, 1011, 994, 965, 940, 908,

875, 852, 811, 775, 696 cm^-1; MS (ESI): m/z: 386 [M+H⁺];

HRMS (EI): m/z calcd for C₂₁H₁₉N₇O: 385.1651 [M⁺]; found:

385.1650.

N-Cyclopropyl-4-((2-(diethylamino)ethyl)(methyl)amino)-1-

(p-tolyl)-1H-pyrazolo[3,4-d]pyrimidine-6-carboxamide (8u):

The procedure for 8a was applied to resin 11u (110 mg,

theoretically 0.0839 mmol). Silica gel column chromatography (a

mixture of methylene chloride and methyl alcohol (30:1)) gave

the desired product 8u (12 mg, 34%). m.p. 119.9 C; H NMR

(300 MHz, CDCl₃): δ=8.20 (s, 1H), 7.91 (br s, 1H), 7.86 (d,

J=8.4 Hz, 2H), 7.35 (d, J=8.4 Hz, 2H), 4.27 (t, J=5.6 Hz, 2H),

3.61 (s, 3H), 3.54 (t, J=5.9 Hz, 2H), 3.34 (m, 4H), 2.88 (m, 1H),

2.45 (s, 3H), 1.36 (m, 6H), 0.89 (m, 2H), 0.66 (m, 2H) ppm; ¹³C

NMR (125 MHz, CDCl₃): δ=164.5, 157.8, 153.9, 153.2, 137.4,

135.9, 134.4, 129.8, 122.4, 102.2, 50.2, 47.7, 42.2, 22.8, 21.1,

11.1, 8.5, 6.8 ppm; IR (ATR, neat): ν=3390, 2990, 2921, 2850,

1733, 1671, 1590, 1513, 1453, 1434, 1420, 1389, 1360, 1291,

1236, 1196, 1172, 1123, 1078, 1009, 970, 943, 853, 822, 797,

775, 718, 676 cm^-1; MS (ESI): m/z: 422 [M+H⁺]; HRMS (EI):

m/z calcd for C₂₃H₃₁N₇O: 421.2590 [M⁺]; found: 421.2588

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1

4-((1-Benzylpiperidin-4-yl)amino)-N-cyclopropyl-1-(4-

methoxyphenyl)-1H-pyrazolo[3,4-d]pyrimidine-6-

carboxamide (8r): The procedure for 8a was applied to resin

11r (145 mg, theoretically 0.105 mmol). Silica gel column

chromatography (a mixture of methylene chloride and methyl

alcohol (15:1)) gave the desired product 8r (37 mg, 71%). m.p.

245.3 ^oC; ¹H NMR (300 MHz, CDCl₃): δ=8.09 (s, 1H), 7.99 (br s,

N-Cyclopropyl-1-(4-fluorophenyl)-4-morpholino-1H-

pyrazolo[3,4-d]pyrimidine-6-carboxamide (8v): The procedure

14

Tetrahedron

ACCEPTED MANUSCRIPT

for 8a was applied to resin 11v (110 mg, theoretically 0.0865

108.9, 108.3, 104.6, 102.0, 101.8, 55.1, 48.9, 23.3, 6.2 (one

mmol). Silica gel column chromatography (a mixture of

methylene chloride and methyl alcohol (30:1)) gave the desired

carbon peak missing) ppm; IR (ATR, neat): ν=3270, 2991, 2835,

2646, 2484, 2221, 1672, 1654, 1605, 1565, 1509, 1495, 1456,

1434, 1392, 1355, 1318, 1295, 1277, 1243, 1200, 1168, 1127,

1092, 1055, 1023, 1002, 965, 940, 849, 830, 798, 776, 715, 681

cm^-1; MS (ESI): m/z: 495 [M+H⁺]; HRMS (EI): m/z calcd for

C₂₇H₂₆N₈O₂: 494.2179 [M⁺]; found: 494.2178.

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1

product 8v (19 mg, 56%). m.p. 196.3 C; H NMR (300 MHz,

CDCl₃): δ=8.15 (s, 1H), 8.11 (m, 2H), 7.83 (br s, 1H), 7.23 (m,

2H), 4.07 (t, J=5.1 Hz, 4H), 3.91 (t, J=5.1 Hz, 4H), 2.92 (m, 1H),

0.89 (m, 2H), 0.66 (m, 2H) ppm; ¹³C NMR (125 MHz, CDCl₃):

δ=164.4, 161.3 (d, J= 244.8 Hz), 157.3, 154.7, 154.4, 134.8,

133.7, 123.9 (d, J= 8.2 Hz), 116.0 (d, J= 22.8 Hz), 101.6, 66.4,

45.7, 22.9, 6.9 ppm; IR (ATR, neat): ν=3189, 2856, 1652, 1567,

1506, 1437, 1393, 1352, 1296, 1284, 1261, 1245, 1212, 1181,

1155, 1114, 1086, 1068, 1032, 1001, 966, 939, 878, 834, 809,

772, 737, 671 cm^-1; MS (ESI): m/z: 383 [M+H⁺]; HRMS (EI):

m/z calcd for C₁₉H₁₉FN₆O₂: 382.1554 [M⁺]; found: 382.1557.

Acknowledgments

Financial support from Korea Research Institute of Chemical

Technology is gratefully acknowledged.

References and notes

N-Cyclopropyl-1-(4-fluorophenyl)-4-(4-(2-furoyl)piperazin-1-

yl)-1H-pyrazolo[3,4-d]pyrimidine-6-carboxamide (8w): The

procedure for 8a was applied to resin 11w (140 mg, theoretically

0.103 mmol). Silica gel column chromatography (a mixture of

methylene chloride and methyl alcohol (30:1)) gave the desired

1. For some general reviews including discussions on the small

organic molecule screening libraries, see: (a) Rankovic, Z.;

Jamieson, C. Morphy, R. In Lead Generation Approaches in Drug

Discovery; Rankovic, Z.; Morphy, R., Eds.; John Wiley & Sons,

Inc.: New Jersey, 2010; pp 21-71; (b) Rydzewski, R. M. Real

World Drug Discovery; Elsevier: Oxford, 2008; pp 218-279; (c)

Ganesan, A. In Exploiting Chemical Diversity for Drug

Discovery; Bartlett, P. A.; Entzeroth, M., Eds.; The Royal Society

of Chemistry: Cambridge, 2006; pp 91-111; (d) Tommasi, R.;

Cornella, I. In Exploiting Chemical Diversity for Drug Discovery;

Bartlett, P. A.; Entzeroth, M., Eds.; The Royal Society of

Chemistry: Cambridge, 2006; pp 163-183.

2. For some examples of design and synthesis of the screening

libraries for hit finding and hit-to-lead process, see: Dolle, R. E.;

Worm, K. In Lead Generation Approaches in Drug Discovery;

Rankovic, Z.; Morphy, R., Eds.; John Wiley & Sons, Inc.: New

Jersey, 2010; pp 259-290.

3. Balkenhohl, F.; von dem Bussche-Huennefeld, C.; Lansky, A.;

Zechel, C. Angew. Chem. Int. Ed. Engl. 1996, 35, 2288-2337.

4. Evans, B. E.; Rittle, K. E.; Bock, M. G.; DiPardo, R. M.;

Freidinger, R. M.; Whitter, W. L.; Lundell, G. F.; Veber, D. F.;

Anderson, P. S.; Chang, R. S. L.; Lotti, V. J.; Cerino, D. J.; Chen,

T. B.; Kling, P. J.; Kunkel, K. A.; Springer, J. P.; Hirshfield, J. J.

Med. Chem. 1988, 31, 2235-2246.

o

1

product 8w (34 mg, 69%). m.p. 228.5 C; H NMR (500 MHz,

CDCl₃): δ=8.19 (s, 1H), 8.13 (dd, J=4.9, 9.1 Hz, 2H), 7.87 (br s,

1H), 7.57(s, 1H), 7.26 (m, 2H), 7.17 (d, J=3.3 Hz, 1H), 6.57 (q,

J=1.7 Hz, 1H), 4.25 (m, 4H), 4.13 (m, 4H), 2.95 (m, 1H), 0.93 (m,

2H), 0.69 (m, 2H) ppm; ¹³C NMR (75 MHz, DMSO-d₆): δ=164.4,

160.2 (d, J= 251.5 Hz), 156.4, 156.3, 155.7, 154.1, 146.9, 145.0,

135.2, 134.9, 123.4 (d, J= 8.4 Hz), 116.0, 115.9 (d, J= 22.7 Hz),

111.4, 101.0, 22.9, 6.0 (two carbon peaks missing) ppm; IR

(ATR, neat): ν=3402, 3119, 3096, 3003, 2847, 1684, 1631, 1559,

1510, 1479, 1435, 1391, 1371, 1340, 1327, 1281, 1258, 1230,

1208, 1183, 1142, 1112, 1090, 1049, 1027, 1183, 1142, 1112,

1090, 1049, 1027, 1005, 967, 944, 885, 851, 835, 807, 776, 750,

690, 671 cm^-1; MS (ESI): m/z: 476[M+H⁺]; HRMS (EI): m/z

calcd for C₂₄H₂₂FN₇O₃: 475.1768 [M⁺]; found: 475.1768.

1-(4-Cyanophenyl)-N-cyclopropyl-4-(4-(pyrrolidin-1-

yl)piperidin-1-yl)pyrazolo[3,4-d]pyrimidine-6-carboxamide

(8x): The procedure for 8a was applied to resin 11x (100 mg,

theoretically 0.0743 mmol). Silica gel column chromatography (a

mixture of methylene chloride and methyl alcohol (20:1)) gave

5. For some review/original articles on the privileged substructure

concept, see: (a) Müller, G. Drug Discov. Today 2003, 8, 681-691;

(b) Schnur, D. M.; Hermsmeier, M. A.; Tebben, A. J. J. Med.

Chem. 2006, 49, 2000-2009; (c) Klekota, J.; Roth, F. P.

Bioinformatics 2008, 24, 2518–2525; (d) Kombarov, R.; Altieri,

A.; Genis, D.; Kirpichenok, M.; Kochubey, V.; Rakitina, N.;

Titarenko, Z. Mol. Divers. 2010, 14, 193–200; (e) Barelier, S.;

Krimm, I. Curr. Opin. Chem. Biol. 2011, 15, 469–474; (f)

Mendgen, T.; Steuer, C.; Klein, C. D. J. Med. Chem. 2012, 55,

743−753; (g) Hu, Y.; Bajorath, J. J. Chem. Inf. Model. 2013, 53,

312−326.

6. For some recent review/original articles on the examples of

privileged substructures, see: (a) Johansson, H.; Boesgaard, M.

W.; Noerskov-Lauritsen, L.; Larsen, I.; Kuhne, S.; Gloriam, D. E.;

Brauner-Osborne, H.; Sejer Pedersen, D. J. Med.

Chem. 2015, 58, 8938-8951; (b) Emami, S.; Ghanbarimasir, Z.

Eur. J. Med. Chem. 2015, 93, 539-563; (c) Song, Y.; Xu, H.;

Chen, W.; Zhan, P.; Liu, X. Med. Chem. Commun. 2015, 6, 61-74;

(d) Stempel, E.; Gaich, T. Acc. Chem. Res. 2016, 49, 2390–2402;

(e) Devi, N.; Singh, D.; Rawal, R. K.; Bariwal, J.; Singh, V. Curr.

Top. Med. Chem. 2016, 16, 2963-2994.

o

1

the desired product 8x (17 mg, 50%). m.p. 258.8 C; H NMR

(500 MHz, DMSO-d₆): δ=8.75 (s, 1H), 8.59 (m, 1H), 8.57 (d,

J=8.7 Hz, 2H), 8.07 (d, J=8.7 Hz, 2H), 2.84 (m, 1H), 2.58 (m,

4H), 2.03 (m, 2H), 1.72 (m, 4H), 1.54 (m, 2H), 1.24 (s, 2H), 1.18

(m, 2H), 0.86 (m, 1H), 0.75 (m, 2H), 0.67 (m, 2H) ppm; ¹³C

NMR (125 MHz, DMSO-d₆): δ=165.0, 156.6, 156.5, 155.8, 142.5,

137.2, 134.1, 121.4, 119.1, 108.8, 101.8, 60.5, 51.3, 30.9, 23.5,

6.4 (two carbon peaks missing) ppm; IR (ATR, neat): ν=3268,

2953, 2919, 2851, 2773, 2220, 1655, 1605, 1565, 159, 1457,

1434, 1392, 1351, 1276, 1238, 1204, 1188, 1167, 1131, 1083,

1048, 1016, 967, 964, 940, 875, 848, 800, 776, 721, 663 cm^-1;

MS (ESI): m/z: 457 [M+H⁺]; HRMS (EI): m/z calcd for

C₂₅H₂₂N₈O₃: 456.2386 [M⁺]; found: 456.2385.

1-(4-Cyanophenyl)-N-cyclopropyl-4-(4-(3-

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methoxyphenyl)piperazin-1-yl)-4,5-dihydro-1H-pyrazolo[3,4-

d]pyrimidine-6-carboxamide (8y): The procedure for 8a was

applied to resin 11y (130 mg, theoretically 0.0939 mmol). Silica

gel column chromatography (a mixture of methylene chloride

and methyl alcohol (20:1)) gave the desired product 8y (25 mg,

49%). m.p. 253.3 ^oC; ¹H NMR (300 MHz, DMSO-d₆): δ=8.77 (s,

1H), 8.63 (d, J=4.2 Hz, 1H), 8.58 (d, J=8.8 Hz, 2H), 8.07 (d,

J=8.8 Hz, 2H), 7.17 (t, J=8.2 Hz, 1H), 6.58 (q, J=2.0 Hz, 1H),

6.50 (t, J=2.1 Hz, 1H), 6.41 (q, J=2.0 Hz, 1H), 4.20 (m, 4H), 3.74

(s, 3H), 3.40 (m, 4H), 2.86 (m, 1H), 0.75 (m, 2H), 0.65 (m, 2H)

ppm; ¹³C NMR (125 MHz, DMSO-d₆): δ=165.0, 160.8, 156.8,

156.3, 155.7, 152.2, 142.4, 136.9, 133.8, 130.1, 121.2, 118.9,

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Supplementary Material

Article Doi

A novel solid-phase synthetic method for production of N-alkyl-4-alkylamino-1-aryl-1H-pyrazolo[3,4-d]pyrimidine-6-carboxamide library

DOI: 10.1016/j.tet.2017.08.044

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Full text of DOI:10.1016/j.tet.2017.08.044

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