Anti-HIV and antiplasmodial activity of original flavonoid derivatives

DOI: 10.1016/j.bmc.2010.06.067

Source and publish data:

Bioorganic and Medicinal Chemistry p. 6012 - 6023 (2010)

Update date:2022-08-03

Topics:

Authors:

Casano, Gilles

Dumtre, Aurélien

Pannecouque, Christophe

Hutter, Sébastien

Azas, Nadine

Robin, Maxime

Read Full Text PDF DownLoad Join now for total 90,000,000 free articles

Article abstract of DOI:10.1016/j.bmc.2010.06.067

In our search for potent anti-HIV and antiplasmodial agents, novel series of flavonoid derivatives and their chalcone intermediates were synthesized and evaluated for inhibition of HIV multiplication and antiproliferative activity on Plasmodium falciparum

Full text of DOI:10.1016/j.bmc.2010.06.067

Bioorganic & Medicinal Chemistry 18 (2010) 6012–6023

Contents lists available at ScienceDirect

Bioorganic & Medicinal Chemistry

journal homepage: w ww.elsevier.com/locate/bmc

Anti-HIV and antiplasmodial activity of original ﬂavonoid derivatives

Gilles Casano ^a, Aurélien Dumètre ^b, Christophe Pannecouque ^c, Sébastien Hutter ^b, Nadine Azas ^b,

Maxime Robin ^a,

^aAix-Marseille Université, Institut des Sciences Moléculaires de Marseille, iSm2-UMR CNRS 6263, Centre Saint Jérôme, Service 552, 13397 Marseille Cedex 20, France

^bUMR MD3 Relations Hôte-Parasites, Pharmacologie et Thérapeutique, Faculté de Pharmacie de Marseille 27 Boulevard Jean Moulin, 13385 Marseille cedex 05, France

^cRega Institute for Medical Research, Katholieke Universiteit Leuven, BP-3000 Leuven, Belgium

a r t i c l e i n f o

a b s t r a c t

Article history:

In our search for potent anti-HIV and antiplasmodial agents, novel series of ﬂavonoid derivatives and

their chalcone intermediates were synthesized and evaluated for inhibition of HIV multiplication and

antiproliferative activity on Plasmodium falciparum parasites. Chalcones exhibited a more selective anti-

plasmodial activity than ﬂavonoids. Methoxyﬂavone 7e was the only one compound active in both P. fal-

ciparum and HIV-1 whereas aminomethoxyﬂavones showed activity against HIV-2. Para substitution on

the B ring seemed to increase HIV-2 potency.

Received 25 February 2010

Revised 10 June 2010

Accepted 21 June 2010

Available online 25 June 2010

Keywords:

Flavonoid

Chalcone

Plasmodium falciparum

HIV-1

HIV-2

Selectivity index

1. Introduction

The ﬂavonoid backbone derives from a chalcone intermediate

and consists of two aromatic rings interconnected by a three car-

The HIV pandemic is still one of the most threatening infectious

diseases despite many efforts to prevent transmission and improve

anti-HIV chemotherapy. Currently available drugs do not com-

pletely eradicate replicating virus and resistant strains are emerg-

ing. HIV is especially widespread in sub-Saharan countries where it

remains difﬁcult to control because of many socio-economical

reasons.

In the same countries, malaria, the most important parasitic

diseases worldwide, leads to 212 million clinical cases and

800,000 deaths each year, mainly in children.¹HIV/malaria co-

infection is a risk factor of clinical malaria during pregnancy and

severe malaria in children and adults.²Malaria management has

become problematic because of the emergence of multidrug-resis-

tant strains of Plasmodium falciparum and the lack of an effective

vaccine.³Thus, one of the major challenges to roll back malaria is

to ﬁnd new active compounds structurally different to current

antiplasmodial molecules for which resistance arises.⁴

bon atom heterocyclic ring (Scheme 1). The subsequent modiﬁca-

tions on this polyphenolic structure can lead to the great

diversity of ﬂavonoid derivatives including ﬂavanones, ﬂavones,

isoﬂavones, ﬂavonols, ﬂavanols, catechins, and anthocyanines.

Flavonoids are commonly found in human diet especially in fruits,

vegetables, tea, red wine, and juices. Consumers and food manufac-

turers are interested in ﬂavonoids because these compounds could

exert direct or indirect beneﬁcial effects on health.

Among their numerous biological activities including antioxi-

dant, antitumor, and anti-inﬂammatory properties, some ﬂavonoid

derivatives were shown to be active on chloroquine-sensitive and

resistant strains of P. falciparum.^6–9Major ﬂavonoids found in hu-

man diet, such as apigenin, luteolin and quercetin, can inhibit par-

asite growth by targeting metabolic pathways occurring in the

apicoplast,^10–13a plastid-like organelle encountered in apicom-

plexan parasites.¹⁴Besides a direct inhibition of the parasitic met-

abolic pathways, ﬂavonoids could disturb the infected-erythrocyte

cytoadherence properties and decrease their sequestration in small

vessels.¹⁵Several ﬂavonoids have an interesting anti-HIV activ-

ity,^7,16for instance thalassiolin A and xanthohumol can inhibit sev-

eral key enzymes involved in the HIV-1 replication.¹⁷

Flavonoids are secondary metabolites widely distributed in

plants. They fulﬁll many functions including ﬂower pigmentation

and protection against plant microorganisms and arthropods.⁵

In order to evaluate the potential anti-HIV and antiplasmodial

activity of ﬂavonoid compounds, we have started a medicinal

chemistry program to highlight a SAR study of chalcone and ﬂavo-

noid derivatives with various substituents on the A, B, and C ring of

* Corresponding authors. Tel./fax: +33 491 835 564 (N.A.); tel.: +33 491 289 059;

fax: +33 491 288 223 (M.R.).

E-mail addresses: nadine.azas@univmed.fr (N. Azas), maxime.robin@univ-

cezanne.fr (M. Robin).

doi:10.1016/j.bmc.2010.06.067

G. Casano et al. / Bioorg. Med. Chem. 18 (2010) 6012–6023

6013

1a-i

Chalcones

Flavones 2a-i

Flavonols 4a-i

6a-i

Methoxyflavones

H₂N

3a-i

Aminoflavones

Aminomethoxyflavones 7a-i

Aminoflavonols 5a-i

Scheme 1. Synthesis of chalcone and ﬂavonoid derivatives.

ﬂavonoids,¹⁸A ring bearing an acetamido or amino group in posi-

tion 6, C ring with H, OH, and OMe in position 3 and mono substit-

uents (H, OMe, F, CF₃) in various position of B ring (Scheme 1). To

perform this SAR study, we have developed microwave irradiation

(MWI) protocols.¹⁹A novel series of ﬂavones and their correspond-

ing chalcone intermediates were synthesized and evaluated

against HIV-1 and HIV-2, and chloroquine-resistant P. falciparum

parasites.

and 6a–i to their corresponding amino derivatives (aminoﬂavones

3a–i, aminoﬂavonols 5a–i, and methoxyaminoﬂavones 7a–i) was

done in ethanol/concentrated H₂SO₄(9:1) under MWI for 30 min

in quantitative yield.

2.2. Biological activity

The cytotoxicity, anti-HIV-1 IIIB, anti-HIV-2 ROD, and antiplas-

modial activity of chalcone and ﬂavonoid derivatives are reported

in Table 2. Overall, chalcone intermediates (1a–i) have a more

selective activity on P. falciparum than ﬂavonoid derivatives (2a–

2. Results and discussion

2.1. Chemistry

7i). IC₅₀W2 of chalcones ranged from 6.7 to 16.9

from 1.3 to 10.2. Only two were cytotoxic for THP1 cells

(IC₅₀THP1 6 15.5 M). This fact was conﬁrmed in the HIV assay

with an homogeneous activity around 40 M (IC₅₀on MT-4 cells

M), but no selective activity was noted

lM and SI W2

Usually, aldol condensation between 2⁰-hydroxyacetophenone

and aldehyde gives chalcone under strong basic condition in etha-

nol for at least 24 h in moderate yields.^20,21So, we have adapted

the Claisen–Schmidt condensation of substituted benzaldehydes²¹

and 2-hydroxy-5-acetamidoacetophenone²²to obtain our chalcone

intermediates (1a–i) in good yields (70–95%) and short time

(20 min) under microwave irradiation (MWI) (Table 1). Chalcones

were converted to ﬂavonols (4a–i) by treatment with alkaline

hydrogen peroxide for 24 h, in yields of 40–70%.^23,24These ﬂavo-

nols were methylated using dimethyl sulfate to obtain 4⁰methoxy

ﬂavones (6a–i). Flavone derivatives (2a–i) were obtained by MWI

of corresponding chalcone in DMSO with catalytic iodine in 90–

95% yields. Deprotection of acetamido intermediates 2a–i, 4a–i,

ranging from 21.1 to 49.8

on both HIV-1 and HIV-2.

Among the ﬂavonoid derivatives, compounds 2c, 2i, 3g, 3i, 4d,

4h, 5c, 5g, 5h, and 6c were highly toxic on THP1 cells

(IC₅₀THP1 = 10 lM) (Table 2). A second class of derivatives in-

cluded moderate cytotoxic but non speciﬁc compounds 2b, 2g,

3a, 3e, 3h, 4a, 4e–g, 5a, 5d–f, 7d, and 7h. The most speciﬁc com-

pounds (SIW2 3.1-8.3) were ﬂavone 2e, aminoﬂavone 3c, meth-

oxyﬂavones 6a, 6b, 6e, 6g, and 6i, and aminomethoxyﬂavones 7a,

7b, and 7e (Table 2). Methoxyﬂavone and aminomethoxyﬂavone

derivatives exhibited the highest speciﬁc activity on P. falciparum

Table 1

Structure and yields of chalcone and ﬂavonoid derivatives synthesized in this study

Chalcone

Flavone

Aminoﬂavone

Flavonol

Aminoﬂavonol

3-Methoxyﬂavone

Amino-3-methoxyﬂavone

97%

92%

98%

89%

87%

88%

90%

98%

81%

84%

87%

91%

98%

95%

94%

96%

95%

41%

94%

98%

97%

98%

96%

94%

95%

86%

88%

84%

91%

82%

71%

86%

85%

93%

80%

76%

91%

93%

82%

89%

91%

77%

86%

2⁰-OCH₃

3⁰-OCH₃

4⁰-OCH₃

2⁰-F

89%

85%

80%

98%

88%

84%

95%

91%

66%

54%

45%

52%

45%

40%

26%

30%

3⁰-F

4⁰-F

3⁰-CF₃

4⁰-CF₃

6014

G. Casano et al. / Bioorg. Med. Chem. 18 (2010) 6012–6023

Table 2

Cytotoxicity, antiplasmodial, anti-HIV-1 and anti-HIV-2 activity of chalcone and ﬂavonoid derivatives

Compound

IC₅₀

THP1

SI W2^b

CC₅₀

(

lM)

IC₅₀

(

SI^e

MT-4

HIV-1III_B

HIV-2 ROD

HIV-1III_B

HIV-2 ROD

85.5

>125

93.7

59.2

>125

78.6

68.8

8.4

15.5

>125

15.9

13.4

13.2

6.7

12.3

15.7

16.9

11.3

11.6

>50

>10

>50

>22

>10

>36

5.4

>9.3

7.1

8.8

>10.2

5.0

4.1

—

1.3

—

49.4

37.8

38.7

33.8

30.1

41.1

32.1

49.8

37.8

38.7

33.8

30.1

41.1

32.1

49.8

37.8

38.7

33.8

30.1

41.1

32.1

—

2.3

—

4.4

—

5.2

—

1.5

—

4.6

—

3.4

—

1.9

—

1.3

6.1

21.1

183.8

226

21.1

183.8

226

21.1

183.8

226

>404

225.8

205.3

239.7

203.1

329.9

209.1

198.1

247.2

240.5

283.3

268.7

264.2

137.6

273.2

64.7

>404

225.8

205.3

239.7

203.1

329.9

209.1

247.2

240.5

284.3

61.1

264.2

137.6

273.2

64.7

>404

225.8

205.3

239.7

203.1

329.9

209.1

198.1

247.2

240.5

283.3

58.4

264.2

137.6

273.2

64.7

384.6

33.3

3.1

>2.5

—

1.5

>4.0

3.5

—

2.5

—

2.2

—

>6.9

6.7

—

>2.4

>8.3

2.6

>5.4

2.7

>3.2

3.7

15.1

2.8

—

>125

124

>125

1.9

>125

>44

>50

>10

>34

>1.9

>36

384.6

33.3

98.7

171.3

26.5

34.1

384.6

33.3

98.7

171.3

26.5

34.1

98.7

171.3

26.5

34.1

5.7

>47

>36

>26

>50

>27

>2.0

>29

>38

>30

>50

7.7

5.7

7.3

5.7

7.3

>50

102

2.0

>125

108

>50

>125

116

7.3

216.5

221.5

40.8

238.9

44.5

35.3

92.6

8.1

3.9

199.6

153.6

368.7

180.3

209.6

316.9

200.7

331.5

126.1

229

250.6

200.2

233.8

112.5

140.6

73.1

216.5

221.5

40.8

238.9

44.5

35.3

92.6

8.1

3.9

199.6

153.6

368.7

180.3

209.6

316.9

200.7

331.5

126.1

229

250.6

200.2

44.7

112.5

140.6

50.4

216.5

221.5

40.8

238.9

44.5

35.3

92.6

8.1

3.9

199.6

153.6

368.7

180.3

209.6

316.9

200.7

331.5

126.1

229

250.6

58.2

233.8

60.7

140.6

57.6

47.7

>125

>21

>34

>33

>5.4

—

1.1

—

289.8

Doxorubicin

Chloroquine

Nevirapine

AZT

0.07

0.7

683

93.55

>529

0.03

0.005

5.37

22,767

>17,990

>98

DDI

2.71

>195

IC₅₀: compound concentration required to inhibit THP1 cell or W2 parasite proliferation by 50%.

SI W2: selectivity index; ratio IC₅₀THP1/IC₅₀W2. —, SI 6 1.

CC₅₀: cytotoxic concentration of compound that reduces the normal uninfected MT-4 cell viability by 50%.

IC₅₀: compound concentration required to inhibit HIV multiplication in MT-4 infected cells by 50%.

SI: selectivity index; ratio CC₅₀/IC₅₀. —, SI 6 1.

G. Casano et al. / Bioorg. Med. Chem. 18 (2010) 6012–6023

6015

strain W2 (best compound 7b, SI = 15.1), even if their SI was much

lower than chloroquine (SI = 57). Investigating the subsequent sub-

stitutions on the phenyl ring B, ﬂuor in position 2 promoted a spe-

ciﬁc antiplasmodial activity of methoxyﬂavone 6e and

aminomethoxyﬂavone 7e.

In the case of HIV activity, there was no speciﬁcity for ﬂavones

(2a–i), aminoﬂavones (3a–i), ﬂavonols (4a–i), aminoﬂavonols (5a–

i), methoxyﬂavones (6a–i) (Table 2). Only six compounds (3b, 3f,

7d, 7e, 7f, 7i) have slight activity against HIV-1 and/or 2 (Table

2). Aminoﬂavone 3f was active on both HIV-1 and 2 (SI >4). 7e

was active against HIV 1 (SI >5) and was the only one that was ac-

tive in both P. falciparum and HIV. Aminomethoxyﬂavones 7d, 7f,

and 7i exhibited inhibitory activities speciﬁcally against HIV-2

H, 5.38; N, 4.89. ¹H NMR (300 MHz, DMSO-d₆) d ppm: 2.03 (s,

3H, CH₃), 6.96 (d, 1H, J = 8.9 Hz, H₅), 7.47 (m, 3H, H₃, H₄, H₅),

7.71 (dd, 1H, J = 2.5 Hz, 8.9 Hz, H₆), 7.77 (s, 2H, C-H₉, H₈), 7.79

(m, 2H, C-H₂, H₆), 8.17 (d, 1H, J = 2.5 Hz, H₂), 10.00 (s, NH),

11.70 (s, OH). ¹³C NMR (75 MHz, DMSO-d₆) d ppm: 23.92 (CH₃),

117.90 (C-5), 121.17 (C-2), 121.46 (C-3), 122.94 (C-8), 128.22 (C-

6), 128.99 (C-3⁰), 129.29 (C-2⁰), 131.13 (C-4⁰), 131.35 (C-1),

134.66 (C-1⁰), 144.30 (C-9), 156.93 (C-4), 168.35 (CO), 193.06 (C-7).

4.1.2.2. (E)-N-(4-Hydroxy-3-(3-(2-methoxyphenyl)acryloyl)phe-

nyl)acetamide (1b). Yellow solid, yield: 89%, mol. wt: 311, mp:

168 °C. Anal. Calcd for C₁₈H₁₇NO₄: C, 69.44; H, 5.50; N, 4.50. Found:

C, 69.32; H, 5.54; N, 4.47. ¹H NMR (300 MHz, DMSO-d₆) d ppm:

2.09 (s, 3H, CH₃), 3.92 (s, 3H, OCH₃), 6.95 (d, 1H, J = 8.9 Hz, H₅),

(ROD) with IC₅₀values in similar range (58.2

lM, 60.7 lM, and

47.7 M, respectively). It was interesting to note that only amino

7.05 (t, 1H, J = 8.2 Hz, H₅), 7.13 (d, 1H, J = 8.2 Hz, H₃), 7.48 (td,

derivatives show activity against HIV. Methoxyﬂavones were the

most representatives, and para substitution on the B ring seems

to increase HIV-2 potency. Such results on HIV-2 are promising be-

cause most of currently approved anti-HIV therapeutics has been

designed against HIV-1 and not HIV-2.²⁵

1H, J = 1.5, 8.2 Hz, H₄), 7.68 (dd, 1H, J = 2.5, 8.9 Hz, H₆), 7.78 (d,

1H, J = 8.2 Hz, H₆), 7.85 (d, 1H, J = 15.7 Hz, H₈), 8.04 (d, 1H,

J = 15.7 Hz, H₉), 8.26 (d, 1H, J = 2.5 Hz, H₂), 9.95 (s, 1H, NH), 11.91

(s, 1H, OH). ¹³C NMR (75 MHz, DMSO-d₆) d ppm: 23.85 (CH₃),

55.83 (OCH₃), 112.03 (C-3⁰), 117.83 (C-5), 120.56 (C-2), 120.90

(C-5⁰), 120.93 (C-3), 122.41 (C-8), 122.82 (C-1⁰), 127.97 (C-6⁰),

129.41 (C-6), 132.69 (C-4⁰), 131.27 (C-1), 139.51 (C-9), 157.17 (C-

4), 158.69 (C-2⁰), 168.22 (CO), 193.22 (C-7).

3. Conclusion

In this newly synthesized series of 54 ﬂavonoid derivatives and

their corresponding chalcones, we obtained a signiﬁcant antiplas-

modial activity of chalcones and methoxyﬂavone derivatives. Ami-

no derivative 7e was active both in P. falciparum and HIV-1

whereas compounds 7d, 7f and 7i were speciﬁc inhibitors of the

HIV-2 multiplication. Para substitution on the B ring is needed to

promote antiplasmodial activity and increase HIV-2 potency.

4.1.2.3. (E)-N-(4-Hydroxy-3-(3-(3-methoxyphenyl)acryloyl)phe-

nyl)acetamide (1c). Yellow solid, yield: 85%, mol. wt: 311, mp:

147 °C. Anal. Calcd for C₁₈H₁₇NO₄: C, 69.44; H, 5.50; N, 4.50. Found:

C, 69.36; H, 5.49; N, 4.46. ¹H NMR (300 MHz, DMSO-d₆) d ppm:

2.02 (s, CH₃), 3.81 (s, OCH₃), 6.96 (d, 1H, J = 8.9 Hz, H₅), 7.04 (m,

1H, H₄), 7.37 (m, 3H, H₂, H₅, H₆), 7.71 (dd, 1H, J = 8.9, 2.5 Hz,

H₆), 7.72 (d, 1H, J = 15.7 Hz, H₈), 7.79 (d, 1H, J = 15.7 Hz, H₉), 8.14

(d, 1H, J = 2.5 Hz, H₂), 9.92 (s, 1H, NH), 11.71 (s, OH). ¹³C NMR

(75 MHz, DMSO-d₆) d ppm: 23.88 (CH₃), 55.50 (OCH₃), 113.97 (C-

2⁰), 116.93 (C-4⁰), 117.86 (C-5), 121.39 (C-3), 121.44 (C-6⁰),

123.26 (C-8), 128.29 (C-6), 130.29 (C-5⁰), 131.27 (C-1), 136.06 (C-

1⁰), 144.28 (C-9), 156.93 (C-4), 159.87 (C-3⁰), 168.28 (CO), 193.13

(C-7).

4. Experimental

4.1. Chemistry

4.1.1. General

Melting points were determined using a Bibby SMP3 apparatus

and were uncorrected. ¹H and ¹³C NMR spectra were recorded on a

Bruker Avance DRX 300 spectrometer. All the experiments were

carried out in DMSO-d₆and the ¹H and ¹³C chemical shifts of the

solvent were used as a secondary reference and referred to the

TMS signal from the usual relationships; the values of the chemical

shifts (d) are given in ppm and coupling constants (J) in Hertz. The

numbering of the carbons is arbitrary. All chemicals used were of

reagent grade, progress of the reaction was monitored by TLC on

silica gel plates (Merck Silica Gel 60 F₂₅₄). Elemental analyses were

performed by Spectropole (Campus St Jerome, Marseille, France)

on a ThermoFinnigan FlashEA 1112 elemental analyzer, and the re-

sults were within 0.4% of the theoretical values. Yields referred to

puriﬁed products and were not optimized.

4.1.2.4. (E)-N-(4-Hydroxy-3-(3-(4-methoxyphenyl) acryloyl)

phenyl) acetamide (1d). Yellow solid, yield: 80%, mol. wt: 311,

mp: 137 °C.²⁰Anal. Calcd for C₁₈H₁₇NO₄: C, 69.44; H, 5.50; N,

4.50. Found: C, 69.41; H, 5.52; N, 4.46. ¹H NMR (300 MHz,

DMSO-d₆) d ppm: 2.04 (s, 3H, CH₃), 3.82 (s, 3H, OCH₃), 6.96 (d,

1H, J = 8.9 Hz, H₅), 7.04 (d, 2H, J = 8.7 Hz, H₃), 7.64 (d, 1H,

J = 15.7 Hz, H₈), 7.71 (dd, 1H, J = 2.5, 8.9 Hz, H₆), 7.78 (d, 2H,

J = 8.7 Hz, H₂), 7.79 (d, 1H, J = 15.7 Hz, H₉), 8.19 (d, 1H, J = 2.5 Hz,

H₂), 9.95 (s, NH), 11.98 (s, OH). ¹³C NMR (75 MHz, DMSO-d₆) d

ppm: 23.72 (CH₃), 55.45 (OCH₃), 114.61 (C-3⁰), 117.69 (C-5),

119.57 (C-3), 120.89 (C-2, C-8), 127.03 (C-1⁰), 128.08 (C-6),

130.84 (C-2⁰), 131.03 (C-1), 144.55 (C-9), 157.10 (C-4), 161.71 (C-

4⁰), 168.13 (CO), 192.89 (C-7).

4.1.2. General procedure for the preparation of compounds (1a–

4.1.2.5. (E)-N-(3-(3-(2-Fluorophenyl)acryloyl)-4-hydroxyphenyl)

acetamide (1e). Yellow solid, yield: 98%, mol. wt: 299, mp: 179 °C.

Anal. Calcd for C₁₇H₁₄FNO₃: C, 68.22; H, 4.71; N, 4.68. Found: C,

68.13; H, 4.70; N, 4.61. ¹H NMR (300 MHz, DMSO-d₆) d ppm:

solution of 2-hydroxy-5-acetamidoacetophenone (1.93 g,

10 mmol), benzaldehyde (10 mmol) and LiOHꢀH₂O (2.94 g,

70 mmol) in MeOH (20 mL) was submitted to microwave irradiation

(MWI) in a CEM Apparatus. MWI Open vessel, power: 300 watts, sol-

vent MeOH, T° = 80 °C, 2 min and 20 min. The colorless solution was

cooled to rt, MeOH was removed under vaccum and the mixture was

poured into 1 N HCl (50 mL). The precipitate obtained was then ﬁl-

tered off, washed with excess water and dried to give chalcone

(1a–i).

2.08 (s, 3H, CH₃), 6.96 (d, 1H, J = 8.9 Hz, H₅), 7.32 (m, 1H, H₅),

7.34 (m, 1H, H₃), 7.53 (m, 1H, H₄), 7.71 (dd, 1H, J = 2.6, 8.9 Hz,

H₆), 7.79 (d, 1H, J = 15.7 Hz, H₈), 7.85 (d, 1H, J = 15.7 Hz, H₉), 7.92

(td, 1H, J = 2.2, 7.6 Hz, H₆), 8.14 (d, 1H, J = 2.6 Hz, H₂), 9.95 (s, 1H,

NH), 11.57 (s, 1H, OH). ¹³C NMR (75 MHz, DMSO-d₆) d ppm:

23.74 (CH₃), 116.13–116.42 (d, J = 21.9 Hz, C-3⁰), 117.75 (C-5),

120.72 (C-2), 121.47 (C-3), 122.13–122.28 (d, J = 11.3 Hz, C-1⁰),

125.13–125.18 (d, J = 3.0 Hz, C-5⁰), 125.46 (C-8), 127.93 (C-6),

129.85–129.88 (d, J = 2.1 Hz, C-6⁰), 131.26 (C-1), 132.77–132.88

4.1.2.1.

(E)-N-(3-Cinnamoyl-4-hydroxyphenyl)

acetamide

(1a). Yellow solid, yield: 97%, mol. wt: 292, mp: 190 °C.²⁰Anal.

Calcd for C₁₇H₁₅NO₃: C, 72.58; H, 5.37; N, 4.98. Found: C, 72.52;

6016

G. Casano et al. / Bioorg. Med. Chem. 18 (2010) 6012–6023

(d, J = 8.3 Hz, C-4⁰), 135.68 (C-9), 156.52 (C-4), 159.38–162.72 (d,

J = 252 Hz, C-2⁰), 168.13 (CO), 192.45 (C-7).

(DMSO, 2 + 20 min, open vessel). The solution was cooled to rt

and poured onto cold 1 N HCl solution (100 mL). The solution

was stirred for 1 h and the orange precipitate was then dilute with

ice water (100 mL) and ﬁltered off. The precipitate collected was

washed with excess water to removed DMSO. The precipitate ob-

tained was ﬁltered off to give 2a–i and used without further

puriﬁcation.

4.1.2.6. (E)-N-(3-(3-(3-Fluorophenyl)acryloyl)-4-hydroxyphenyl)

acetamide (1f). Yellow solid, yield: 88%, mol. wt: 299, mp: 169 °C.

Anal. Calcd for C₁₇H₁₄FNO₃: C, 68.22; H, 4.71; N, 4.68. Found: C,

68.15; H, 4.73; N, 4.58. ¹H NMR (300 MHz, DMSO-d₆) d ppm:

2.02 (s, 3H, CH₃), 6.96 (d, 1H, J = 8.9 Hz, H₅), 7.29 (td, 1H, J = 2.6,

8.6 Hz, H₄), 7.50 (m, 1H, H₅), 7.63 (d, 1H, J = 7.8 Hz, H₂), 7.72 (m,

4.1.3.1. N-(4-Oxo-2-phenyl-4H-chromen-6-yl) acetamide (2a). Yel-

low solid, yield: 92%, mol. wt: 279, mp: 250.8 °C,²⁰Anal. Calcd for

2H, H_{6 ,6}), 7.74 (d, 1H, J = 15.7 Hz, H₈), 7.82 (d, 1H, J = 15.7 Hz,

H₉), 8.11 (d, 1H, J = 2.4 Hz, H₂), 9.87 (s, 1H, NH), 11.63 (s, 1H,

OH). ¹³C NMR (75 MHz, DMSO-d₆) d ppm: 23.84 (CH₃), 114.83–

115.12 (d, J = 21.9 Hz, C-2⁰), 117.52–117.80 (d, J = 21.1 Hz, C-4⁰),

117.87 (C-5), 121.46 (C-2), 121.46 (C-3), 121.46 (C-6⁰), 125.34 (C-

8), 128.52 (C-6), 131.23 (C-1), 131.13–131.23 (d, J = 7.5 Hz, C-5⁰),

137.19–137.29 (d, J = 7.5 Hz, C-1⁰), 142.66 (C-9), 156.95 (C-4),

161.06–164.29 (d, J = 243 Hz, C-3⁰), 168.29 (CO), 193.00 (C-7).

C₁₇H₁₃NO₃: C, 73.11; H, 4.69; N, 5.02. Found: C, 73.02; H, 4.71; N,

5.00. H NMR (300 MHz, DMSO-d₆) d ppm: 2.09 (s, 3H, CH₃), 7.00 (s,

1H, H₇), 7.58 (m, 1H, H₄), 7.60 (m, 2H, H₃), 7.75 (d, 1H, J = 9.0 Hz,

H₄), 7.96 (dd, 1H, J = 2.7 Hz, 9.0 Hz, H₃), 8.10 (m, 2H, H₂), 8.34 (d,

1H, J = 2.7 Hz, H₁), 10.27 (s, NH). ¹³C NMR (75 MHz, DMSO-d₆) d

ppm: 23.98 (CH₃), 106.42 (C-7), 113.01 (C-1), 119.01 (C-4), 123.50

(C-8a), 125.56 (C-3), 126.29 (C-2⁰), 129.11 (C-3⁰), 131.21 (C-1⁰),

131.74 (C-4⁰), 136.79 (C-2), 151.49 (C-4a), 162.34 (C-6), 168.55 (CO),

176.98 (C-8).

4.1.2.7. (E)-N-(3-(3-(4-Fluorophenyl)acryloyl)-4-hydroxyphenyl)

acetamide (1g). Yellow solid, yield: 84%, mol. wt: 299, mp: 153 °C.

Anal. Calcd for C₁₇H₁₄FNO₃: C, 68.22; H, 4.71; N, 4.68. Found: C,

68.20; H, 4.68; N, 4.60. ¹H NMR (300 MHz, DMSO-d₆) d ppm:

2.03 (s, 3H, CH₃), 6.97 (d, 1H, J = 8.9 Hz, H₅), 7.32 (t, 2H,

4.1.3.2. N-(2-(2-Methoxyphenyl)-4-oxo-4H-chromen-6-yl)acet-

amide (2b). Pale yellow solid, yield: 98%, mol. wt: 309. Anal. Calcd

for C₁₈H₁₅NO₄: C, 69.89; H, 4.89; N, 4.53. Found: C, 69.79; H, 4.92;

N, 4.46. ¹H NMR (300 MHz, DMSO-d₆) d ppm: 2.06 (s, 3H, CH₃), 3.79

J = 8.9 Hz, H₃), 7.71 (dd, 1H, J = 2.5, 8.9 Hz, H₆), 7.73 (d, 1H,

J = 15.7 Hz, H₈), 7.78 (d, 1H, J = 15.7 Hz, H₉), 7.90 (t, 2H, J = 8.9 Hz,

(s, 3H, OCH_3–2), 6.84 (s, 1H, H₇), 7.10 (t, 1H, J = 8.2 Hz, H₅), 7.20 (d,

H₂), 8.18 (d, 1H, J = 2.5 Hz, H₂), 10.01 (s, 1H, NH), 11.73 (s, 1H,

1H, J = 8.2 Hz, H₃), 7.52 (td, 1H, J = 8.2, 1.5 Hz, H₄), 7.64 (d, 1H,

OH). ¹³C NMR (75 MHz, DMSO-d₆) d ppm: 23.70 (CH₃), 116.00–

116.29 (d, J = 21.9 Hz, C-3⁰), 117.68 (C-5), 121.11 (C-2), 121.26

(C-3), 122.69 (C-8), 122.69 (C-1⁰), 128.10 (C-6), 131.12 (C-1),

131.12–131.25 (d, J = 9.8 Hz, C-2⁰), 142.87 (C-9), 156.74 (C-4),

161.92–165.22 (d, J = 249.0 Hz, C-4⁰), 168.13 (CO), 192.81 (C-7).

J = 9.1 Hz, H₄), 7.85 (dd, 1H, J = 8.2, 1.5 Hz, H₆), 7.89 (dd, 1H,

J = 9.1, 2.5 Hz, H₃), 8.30 (d, 1H, J = 2.5 Hz, H₁), 10.23 (s, 1H, NH).

¹³C NMR (75 MHz, DMSO-d₆) d ppm: 4.01 (CH₃), 55.98 (OCH_3–2),

111.09 (C-3⁰), 112.59 (C-7), 112.94 (C-1), 118.96 (C-4), 119.99 (C-

1⁰), 120.76 (C-5⁰), 123.25 (C-8a), 125.54 (C-3), 129.15 (C-6⁰),

132.86 (C-4⁰), 136.67 (C-2), 151.76 (C-4a), 157.58 (C-2⁰), 160.47

(C-6), 168.58 (CO), 177.02 (C-8).

4.1.2.8. (E)-N-(4-Hydroxy-3-(3-(3-(triﬂuoromethyl)phenyl)acry-

loyl)phenyl)acetamide (1h). Yellow solid, yield: 95%, mol. wt:

349, mp: 169 °C. Anal. Calcd for C₁₈H₁₄F₃NO₃: C, 61.89; H, 4.04;

N, 4.01. Found: C, 61.81; H, 4.09; N, 3.99. ¹H NMR (300 MHz,

DMSO-d₆) d ppm: 2.02 (s, 3H, CH₃), 6.97 (d, 1H, J = 8.9 Hz, H₅),

4.1.3.3. N-(2-(3-Methoxyphenyl)-4-oxo-4H-chromen-6-yl)acet-

amide (2c). Pale yellow solid, yield: 89%, mol. wt: 309, mp: 198 °C.

Anal. Calcd for C₁₈H₁₅NO₄: C, 69.89; H, 4.89; N, 4.53. Found: C,

69.81; H, 4.88; N, 4.49. ¹H NMR (300 MHz, DMSO-d₆) d ppm:

2.09 (s, 3H, CH₃), 3.87 (s, 3H, OCH₃), 7.02 (s, 1H, H₇), 7.15 (m, 1H,

7.69 (t, 1H, J = 7.9 Hz, H₅), 7.71 (dd, 1H, J = 2.6, 8.9 Hz, H₆), 7.82

(t, 1H, J = 7.9 Hz, H₄), 7.83 (d, 1H, J = 15.7 Hz, H₈), 7.93 (d, 1H,

J = 15.7 Hz, H₉), 8.10 (d, 1H, J = 2.6 Hz, H₂), 8.11 (br d, 1H, J =

H₄), 7.47 (t, 1H, J = 7.9 Hz, H₅), 7.57 (t, 1H, J = 2.4 Hz, H₂), 7.64

7.9 Hz, H₆), 8.21 (br s, 1H, H₂), 9.91 (s, 1H, NH), 11.60 (s, 1H,

OH). ¹³C NMR (75 MHz, DMSO-d₆) d ppm: 23.85 (CH₃), 117.87

(C-5), 121.48 (C-2), 121.68 (C-3), 125.28 (C-8), 124.20 (q,

J = 270.00 Hz, CF₃), 125.36 (q, J = 4.2 Hz, C-2⁰), 127.08 (q,

J = 4.2 Hz, C-4⁰), 128.54 (C-6), 130.08 (q, J = 31.7 Hz, C-3⁰), 130.29

(C-5⁰), 131.24 (C-1), 132.67 (C-6⁰), 135.89 (C-1⁰), 142.17 (C-9),

156.85 (C-4), 168.28 (CO), 192.93 (C-7).

(m, 1H, H₆), 7.73 (d, 1H, J = 9.2 Hz, H₄), 7.94 (dd, 1H, J = 2.4,

9.0 Hz, H₃), 8.33 (d, 1H, J = 2.2 Hz, H₁), 10.30 (s, 1H, NH). ¹³C

NMR (75 MHz, DMSO-d₆) d ppm: 24.02 (CH₃), 106.72 (C-7),

111.50 (C-2⁰), 113.01 (C-1), 117.59 (C-4⁰), 118.60 (C-6⁰), 119.10

(C-4), 123.51 (C-8a), 125.61 (C-3), 130.31 (C-5⁰), 132.64 (C-1⁰),

136.82 (C-2), 151.51 (C-4a), 159.79 (C-3⁰), 162.15 (C-6), 168.64

(CO), 177.08 (C-8).

4.1.2.9. (E)-N-(4-Hydroxy-3-(3-(4-(triﬂuoromethyl)phenyl)acry-

loyl)phenyl)acetamide (1i). Yellow solid, yield: 91%, mol. wt: 349,

mp: 171 °C. Anal. Calcd for C₁₈H₁₄F₃NO₃: C, 61.89; H, 4.04; N, 4.01.

Found: C, 61.78; H, 4.06; N, 4.02. ¹H NMR (300 MHz, DMSO-d₆) d

ppm: 2.02 (s, 3H, CH₃), 6.97 (d, 1H, J = 8.9 Hz, H₅), 7.70 (dd, 1H,

J = 2.5, 8.9 Hz, H₆), 7.79 (d, 1H, J = 15.7 Hz, H₈), 7.82 (d, 2H,

4.1.3.4. N-(2-(4-Methoxyphenyl)-4-oxo-4H-chromen-6-yl)acet-

amide (2d). Dark red solid, yield: 87%, mol. wt: 309, mp: 255 °C.²⁰

Anal. Calcd for C₁₈H₁₅NO₄: C, 69.89; H, 4.89; N, 4.53. Found: C,

69.84; H, 4.90; N, 4.52. ¹H NMR (300 MHz, DMSO-d₆) d ppm:

2.08 (s, 3H, CH₃), 3.85 (s, 3H, OCH₃), 6.90 (s, 1H, H₇), 7.12 (d, 2H,

J = 8.9 Hz, H₃), 7.72 (d, 1H, J = 9.1 Hz, H₄), 7.94 (d, 1H, J = 9.1,

J = 8.2 Hz, H₂), 7.89 (d, 1H, J = 15.7 Hz, H₉), 8.01 (d, 2H, J = 8.2 Hz,

2.5 Hz, H₃), 8.04 (d, 2H, J = 2.7 Hz, 9.0 Hz, H₂), 8.31 (d, 1H,

H₃), 8.11 (d, 1H, J = 2.5 Hz, H₂), 9.92 (s, 1H, NH), 11.50 (s, 1H,

J = 2.5 Hz, H₁), 10.27 (s, NH). ¹³C NMR (75 MHz, DMSO-d₆) d

ppm: 24.01 (CH₃), 55.56 (OCH₃), 105.00 (C-7), 113.13 (C-1),

114.61 (C-3⁰), 118.91 (C-4), 123.35 (C-1⁰, C-8a), 125.40 (C-3),

128.19 (C-2⁰), 136.69 (C-2), 151.46 (C-4a), 162.14 (C-6), 162.50

(C-4⁰), 168.61 (CO), 176.86 (C-8).

OH). ¹³C NMR (75 MHz, DMSO-d₆) d ppm: 23.85 (CH₃), 117.87

(C-5), 121.28 (C-2), 121.78 (C-3), 124.09 (q, J = 269.0 Hz, CF₃),

126.04 (C-8), 126.05 (q, J = 3.8 Hz, C-3⁰), 128.27 (C-6), 129.43 (C-

2⁰), 130.27 (q, J = 32.1 Hz, C-4⁰), 131.31 (C-1), 138.70 (C-1⁰),

141.79 (C-9), 156.60 (C-4), 168.24 (CO), 192.66 (C-7).

4.1.3.5. N-(2-(2-Fluorophenyl)-4-oxo-4H-chromen-6-yl)acetam-

ide (2e). Black solid, yield: 87%, mol. wt: 297. Anal. Calcd for

C₁₇H₁₂FNO₃: C, 68.68; H, 4.07; N, 4.71. Found: C, 68.61; H, 4.11;

N, 4.69. ¹H NMR (300 MHz, DMSO-d₆) d ppm: 2.07 (s, 3H, CH₃),

4.1.3. General procedure for the preparation of compounds (2a–

Chalcone 1a–i (10 mmol), I₂(0.28 g, 10% wt) were solubilized in

DMSO (10 mL). The solution was submitted to MWI at 140 °C

6.70 (s, 1H, H₇), 7.40 (t, 1H, J = 7.8 Hz, H₅), 7.42 (m, 1H, H₃), 7.62

G. Casano et al. / Bioorg. Med. Chem. 18 (2010) 6012–6023

6017

(m, 1H, H₄), 7.65 (d, 1H, J = 9.1 Hz, H₄), 7.93 (dd, 1H, J = 2.6, 9.0 Hz,

4.1.4. General procedure for deprotection of acetamido

derivatives (3a–i)

H₃), 7.95 (dd, 1H, J = 2.2, 7.6 Hz, H₆), 8.31 (d, 1H, J = 2.6 Hz, H₁),

10.26 (s, 1H, NH). ¹³C NMR (75 MHz, DMSO-d₆) d ppm: 24.18

(CH₃), 111.01–111.14 (d, J = 8.3 Hz, C-6⁰), 113.11 (C-1), 116.94–

117.23 (d, J = 22.6 Hz, C-3⁰), 119.24 (C-7), 119.81–119.89 (d,

J = 14.3 Hz, C-1⁰), 123.47 (C-8a), 125.37 (C-5⁰), 125.97 (C-3),

129.75 (C-4), 133.71–133.84 (d, J = 6.8 Hz, C-1⁰), 137.12 (C-2),

151.84 (C-4a), 159.50 (C-6), 158.18–161.54 (d, J = 248.0 Hz, C-2⁰),

168.80 (CO), 176.93 (C-8).

Flavones 2a–i (10 mmol) were added to a solution of EtOH

(20 mL) and H₂SO₄concd (5 mL). The solution was submitted to

MWI in open vessel 80 °C, 2 + 20 min, upon cooling the solvent

was removed under vacuo and the residue obtain is poured onto

ice water (100 mL). Then the solution was neutralized with NH₄OH

16% until pH 7. The red precipitate formed was collected by ﬁltra-

tion and washed with excess cold water. Amino compound was ob-

tained as a red powder without further puriﬁcation.

4.1.3.6. N-(2-(3-Fluorophenyl)-4-oxo-4H-chromen-6-yl)acetam-

ide (2f). Gray solid, yield: 88%, mol. wt: 297. Anal. Calcd for

4.1.4.1. 6-Amino-2-phenyl-4H-chromen-4-one (3a). Brown solid,

yield: 84%, mol. wt: 237, mp: 151 °C. Anal. Calcd for C₁₅H₁₁NO₂: C,

75.94; H, 4.67; N, 5.90. Found: C, 75.88; H, 4.72; N, 5.81. ¹H NMR

(300 MHz, DMSO-d₆) d ppm: 6.87 (s, 1H, H₇), 7.09 (dd, 1H, J = 8.8,

2.7 Hz, H₃), 7.13 (d, 1H, J = 2.7 Hz, H₁), 7.51 (d, 1H, J = 8.8 Hz, H₄),

₁₇H₁₂FNO₃: C, 68.68; H, 4.07; N, 4.71. Found: C, 68.64; H, 4.10;

N, 4.67. ¹H NMR (300 MHz, DMSO-d₆) d ppm: 2.09 (s, 3H, CH₃),

7.06 (s, 1H, H₇), 7.43 (td, 1H, J = 8.5, 2.3 Hz, H₄), 7.61 (td, 1H,

J = 8.0, 6.3 Hz, H₅), 7.73 (d, 1H, J = 9.0 Hz, H₄), 7.92 (br d, 1H,

J = 8.0 Hz, H₆), 7.93 (dd, 1H, J = 9.0, 2.7 Hz, H₃), 7.94 (dt, 1H, 11.1,

7.57 (m, 1H, H₄), 7.58 (m, 2H, H₃), 8.05 (m, 2H, H₂). ¹³C NMR

(75 MHz, DMSO-d₆) d ppm: 105.24 (C-1), 105.77 (C-7), 119.03 (C-

4), 121.91 (C-3), 124.23 (C-8a), 126.11 (C-2⁰), 129.08 (C-3⁰),

131.43 (C-1⁰), 131.60 (C-4⁰), 146.23 (C-2), 148.08 (C-4a), 161.70

(C-6), 177.14 (C-8).

1.8 Hz, H₂), 8.31 (d, 1H, J = 2.7 Hz, H₁), 10.27 (s, 1H, NH). ¹³C

NMR (75 MHz, DMSO-d₆) d ppm: 24.00 (CH₃), 107.11 (C-7),

112.95 (C-1), 113.03–113.34 (d, J = 23.4 Hz, C-2⁰), 118.36–118.64

(d, J = 21.1 Hz, C-4⁰), 119.08 (C-4), 121.41–121.44 (d, J = 2.1 Hz, C-

6⁰), 123.47 (C-8a), 125.64 (C-3), 131.16–131.27 (d, J = 8.3 Hz,

C-5⁰), 133.56–133.66 (d, J = 7.5 Hz, C-1⁰), 136.89 (C-2), 151.41

(C-4a), 160.81 (C-6), 160.80–164.07 (d, J = 246 Hz, C-3⁰), 168.59

(CO), 177.02 (C-8).

4.1.4.2. 6-Amino-2-(2-methoxyphenyl)-4H-chromen-4-one

(3b). Brown solid, yield: 87%, mol. wt: 267. Anal. Calcd for

₁₆H₁₃NO₃: C, 71.90; H, 4.90; N, 5.24. Found: C, 71.84; H,

4.95; N, 5.21. ¹H NMR (300 MHz, DMSO-d₆) d ppm: 3.90 (s,

4.1.3.7. N-(2-(4-Fluorophenyl)-4-oxo-4H-chromen-6-yl)acetam-

ide (2g). Brown solid, yield: 90%, mol. wt: 297, mp: 274 °C. Anal.

Calcd for C₁₇H₁₂FNO₃: C, 68.68; H, 4.07; N, 4.71. Found: C, 68.66;

H, 4.10; N, 4.65. ¹H NMR (300 MHz, DMSO-d₆) d ppm: 2.08 (s,

3H, OCH _3–2), 5.75 (br s, 2H, NH₂), 6.76 (s, 1H, H₇), 7.08 (dd,

1H, J = 8.9, 2.5 Hz, H₃), 7.12 (t, 1H, J = 8.2 Hz, H₅), 7.14 (d,

1H, J = 2.5 Hz, H₁), 7.22 (d, 1H, J = 8.2 Hz, H₃), 7.45 (d, 1H,

J = 8.9 Hz, H₄), 7.54 (td, 1H, J = 8.2, 1.5 Hz, H₄), 7.84 (dd, 1H,

J = 8.2, 1.5 Hz, H₆). ¹³C NMR (75 MHz, DMSO-d₆) d ppm:

3H, CH₃), 6.97 (s, 1H, H₇), 7.40 (t, 2H, J = 8.9 Hz, H₃), 7.71 (d, 1H,

J = 9.1 Hz, H₄), 7.94 (dd, 1H, J = 9.1, 2.5 Hz, H₃), 8.14 (dd, 2H,

55.92 (OCH _3–2), 105.30 (C-1), 110.52 (C-3 ), 112.48 (C-7),

J = 8.9, 5.3 Hz, H₂), 8.31 (d, 1H, J = 2.6 Hz, H₁), 10.26 (s, 1H, NH).

118.96 (C-4), 120.49 (C-1⁰), 120.76 (C-5⁰), 121.96 (C-3),

123.99 (C-8a), 129.06 (C-6⁰), 132.51 (C-4⁰), 145.95 (C-2),

148.45 (C-4a), 157.41 (C-2⁰), 159.91 (C-6), 177.13 (C-8).

¹³C NMR (75 MHz, DMSO-d₆) d ppm: 23.98 (CH₃), 106.32 (C-7),

113.00 (C-1), 116.15–116.43 (d, J = 22.6 Hz, C-3⁰), 118.99 (C-4),

123.40 (C-8a), 125.55 (C-3), 127.80 (C-1⁰), 128.98 (d, J = 9.8 Hz, C-

2⁰), 136.80 (C-2), 151.43 (C-4a), 161.40 (C-6), 162.34–165.25 (d,

J = 250.00 Hz, C-4⁰), 168.56 (CO), 176.92 (C-8).

4.1.4.3. 6-Amino-2-(3-methoxyphenyl)-4H-chromen-4-one

(3c). Brown solid, yield: 91%, mol. wt: 267. Anal. Calcd for

₁₆H₁₃NO₃: C, 71.90; H, 4.90; N, 5.24. Found: C, 71.81; H,

4.1.3.8. N-(4-Oxo-2-(3-(triﬂuoromethyl)phenyl)-4H-chromen-

6-yl)acetamide (2h). Brown solid, yield: 98%, mol. wt: 347. Anal.

Calcd for C₁₈H₁₂F₃NO₃: C, 62.25; H, 3.48; N, 4.03. Found: C,

62.21; H, 3.49; N, 3.98. ¹H NMR (300 MHz, DMSO-d₆) d ppm:

2.08 (s, 3H, CH₃), 7.18 (s, 1H, H₇), 7.80 (d, 1H, J = 8.9 Hz, H₄), 7.81

4.91; N, 5.25. ¹H NMR (300 MHz, DMSO-d₆) d ppm: 3.86 (s,

3H, OCH₃), 6.91 (s, 1H, H₇), 7.09 (dd, 1H, J = 2.8, 8.9 Hz, H₃),

7.12 (d, 1H, J = 8.9 Hz, H₁), 7.15 (m, 1H, H₄), 7.47 (t, 1H,

J = 7.9 Hz, H₅), 7.53 (d, 1H, J = 9.1 Hz, H₄), 7.55 (t, 1H,

J = 2.3 Hz, H₂), 7.62 (m, 1H, H₆). ¹³C NMR (75 MHz, DMSO-

d₆) d ppm: 55.75 (OCH₃), 105.31 (C-1), 106.08 (C-7), 111.31

(C-2⁰), 117.24 (C-4⁰), 118.40 (C-6⁰), 119.11 (C-4), 122.07 (C-

3), 124.23 (C-8a), 130.22 (C-5⁰), 133.01 (C-1⁰), 145.85 (C-2),

148.21 (C-4a), 159.69 (C-3⁰), 161.48 (C-6), 177.16 (C-8).

(t, 1H, J = 8.2 Hz, H₅), 7.96 (dd, 1H, J = 8.9, 2.6 Hz, H₃), 7.96 (br d,

1H, J = 8.2 Hz, H₄), 8.32 (d, 1H, J = 2.6 Hz, H₁), 8.39 (br d, 1H,

J = 8.2 Hz, H₆), 8.40 (br s, 1H, H₂), 10.28 (s, 1H, NH). ¹³C NMR

(75 MHz, DMSO-d₆) d ppm: 24.01 (CH₃), 107.50 (C-7), 112.96 (C-

1), 119.21 (C-4), 122.90 (q, J = 3.8 Hz, C-2⁰), 123.42 (q,

J = 270.00 Hz, CF₃), 123.51 (C-8a), 125.70 (C-3), 128.08 (q,

J = 3.8 Hz, C-4⁰), 129.99 (q, J = 31.7 Hz, C-3⁰), 130.33 (C-5⁰, C-6⁰),

132.48 (C-1⁰), 136.94 (C-2), 151.49 (C-4a), 160.60 (C-6), 168.61

(CO), 177.04 (C-8).

4.1.4.4. 6-Amino-2-(4-methoxyphenyl)-4H-chromen-4-one

(3d). Dark brown solid, yield: 80%, mol. wt: 267, mp:

147 °C.²⁰Anal. Calcd for C₁₆H₁₃NO₃: C, 71.90; H, 4.90; N,

5.24. Found: C, 71.83; H, 4.97; N, 5.19. ¹H NMR (300 MHz,

DMSO-d₆) d ppm: 3.85 (s, OCH₃), 5.49 (s, NH₂), 6.78 (s, 1H,

H₇), 7.06 (dd, 1H, J = 8.8, 2.7 Hz, H₃), 7.08 (d, 1H, J = 2.7 Hz,

4.1.3.9. N-(4-Oxo-2-(4-(triﬂuoromethyl)phenyl)-4H-chromen-

6-yl)acetamide (2i). Brown solid, yield: 81%, mol. wt: 347, mp:

293 °C. Anal. Calcd for C₁₇H₁₂FNO₃: C, 62.25; H, 3.48; N, 4.03.

Found: C, 62.18; H, 3.52; N, 3.95. ¹H NMR (300 MHz, DMSO-d₆) d

ppm: 2.09 (s, 3H, CH₃), 7.15 (s, 1H, H₇), 7.78 (d, 1H, J = 9.1 Hz,

H₁), 7.10 (d, 2H, J = 8.9 Hz, H₃), 7.47 (d, 1H, J = 8.8 Hz, H₄),

8.00 (d, 2H, J = 8.9 Hz, H₂). ¹³C NMR (75 MHz, DMSO-d₆) d

ppm: 55.49 (OCH₃), 104.38 (C-1), 105.01 (C-7), 114.51 (C-

3⁰), 118.83 (C-4), 121.45 (C-3), 123.78 (C-1⁰), 124.18 (C-8a),

127.89 (C-2⁰), 146.55 (C-2), 147.81 (C-4a), 161.82 (C-6, C-

4⁰), 177.03 (C-8).

H₄), 7.94 (d, 2H, J = 8.8 Hz, H₃)_,7.97 (dd, 1H, J = 9.1, 2.5 Hz, H₃),

8.31 (d, 2H, J = 8.8 Hz, H₂), 8.35 (d, 1H, J = 2.5 Hz, H₁), 10.30 (br s,

NH). ¹³C NMR (75 MHz, DMSO-d₆) d ppm: 22.99 (CH₃), 107.84

(C-7), 112.94 (C-1), 119.12 (C-4), 123.50 (C-8a), 124.81 (q,

J = 272 Hz, CF₃), 125.78 (C-3), 125.95 (q, J = 3.8 Hz, C-3⁰), 127.17

(C-2⁰), 131.27 (q, J = 32.4 Hz, C-4⁰), 135.19 (C-1⁰), 136.96 (C-2),

151.47 (C-4a), 160.62 (C-6), 168.61 (CO), 176.99 (C-8).

4.1.4.5. 6-Amino-2-(2-ﬂuorophenyl)-4H-chromen-4-one (3e). Dark

brown solid, yield: 98%, mol. wt: 255. Anal. Calcd for C₁₅H₁₀FNO₂: C,

70.58; H, 3.95; N, 5.49. Found: C, 70.43; H, 3.98; N, 5.51. ¹H NMR

(300 MHz, DMSO-d₆) d ppm: 6.93 (s, 1H, H₇), 5.55 (s, 2H, NH₂), 7.09

6018

G. Casano et al. / Bioorg. Med. Chem. 18 (2010) 6012–6023

(dd, 1H, J = 2.7, 8.8 Hz, H₃), 7.11 (d, 1H, J = 2.7 Hz, H₁), 7.41 (m, 1H, H ),

4.1.5.1. N-(3-Hydroxy-4-oxo-2-phenyl-4H-chromen-6-yl)acet-

amide (4a)²⁶. Yellow solid, yield: 41%, mol. wt: 295. Anal. Calcd

for C₁₇H₁₃NO₄: C, 69.15; H, 4.44; N, 4.74. Found: C, 69.12; H,

4.48; N, 4.68. ¹H NMR (300 MHz, DMSO-d₆) d ppm: 2.08 (s, 3H,

7.44 (m, 1H, H ), 7.46 (d, 1H, J = 8.8 Hz, H₄), 7.65 (m, 1H, H ), 7.95 (td,

1H, J = 7.6, 2.1 Hz, H ). ¹³C NMR (75 MHz, DMSO-d₆) d ppm: 104.72 (C-

1), 110.18–110.30 (d, J = 9.0 Hz, C-7), 116.73–116.02 (d, J = 21.9 Hz, C-

3⁰), 119.01 (C-4), 120.03–120.16 (d, J = 9.8 Hz, C-1⁰), 121.94 (C-3),

CH₃), 7.51 (m, 1H, H₄), 7.55 (m, 2H, H₃), 7.71 (d, 1H, J = 9.2 Hz,

124.05 (C-8a), 125.19 (C-5 ), 129.47 (C-6⁰), 132.23–132.35 (d, J = 9.1 Hz,

H₄), 7.90 (dd, 1H, J = 2.5 Hz, 9.2 Hz, H₃), 8.19 (m, 2H, H₂), 8.42 (d,

C-4⁰), 146.85 (C-2), 148.09 (C-4a), 157.72 (C-6), 157.90–161.26 (d,

1H, J = 2.5 Hz, H₁), 9.53 (s, OH), 10.30 (s, NH). ¹³C NMR (75 MHz,

DMSO-d₆) d ppm: 24.09 (CH₃), 112.77 (C-1), 119.08 (C-4), 121.48

(C-8a), 125.74 (C-3), 127.75 (C-2⁰), 128.68 (C-3⁰), 130.02 (C-1⁰),

131.43 (C-4⁰), 136.05 (C-2), 138.87 (C-7), 145.25 (C-6), 150.76 (C-

4a), 168.84 (CO), 172.96 (C-8).

J = 253.00 Hz, C-2⁰), 176.84 (C-8).

4.1.4.6. 6-Amino-2-(3-ﬂuorophenyl)-4H-chromen-4-one (3f). Brown

solid, yield: 95%, mol. wt: 255, mp: 122 °C. Anal. Calcd for C₁₅H₁₀FNO₂:

C, 70.58; H, 3.95; N, 5.49. Found: C, 70.43; H, 3.98; N, 5.51. ¹H NMR

(300 MHz, DMSO-d₆) d ppm: 6.95 (s, 1H, H₇), 7.07 (dd, 1H, J = 9.0,

2.7 Hz, H₃), 7.10 (br s, 2H, NH₂), 7.11 (d, 1H, J = 2.7 Hz, H₁), 7.42 (td,

4.1.5.2.

N-(3-Hydroxy-2-(2-methoxyphenyl)-4-oxo-4H-chro-

men-6-yl)acetamide (4b). White solid, yield: 66%, mol. wt: 325.

Anal. Calcd for C₁₈H₁₅NO₅: C, 66.46; H, 4.65; N, 4.31. Found: C,

66.42; H, 4.71; N, 4.28. ¹H NMR (300 MHz, DMSO-d₆) d ppm:

1H, J = 8.5, 2.3 Hz, H₄), 7.52 (d, 1H, J = 9.0 Hz, H₄), 7.61 (td, 1H, J = 8.0,

6.3 Hz, H₅), 7.91 (br d, 1H, J = 8.0 Hz, H₆), 7.91 (dt, 1H, J = 11.1, 1.8 Hz,

H₂). ¹³C NMR (75 MHz, DMSO-d₆) d ppm: 104.83 (C-1), 106.43 (C-7),

2.10 (s, 2H, CH₃), 3.79 (s, 3H, OCH_3–2), 7.08 (t, 1H, J = 8.2 Hz, H₅),

112.83–113.14 (d, J = 23.3 Hz, C-2⁰), 118.03–118.16 (d, J = 20.4 Hz, C-

4⁰), 119.08 (C-4), 121.88 (C-3), 122.26 (C-6⁰), 124.23 (C-8a), 131.14–

131.25 (d, J = 8.3 Hz, C-5⁰), 133.99–134.11 (d, J = 8.9 Hz, C-1⁰), 146.72

(C-2), 147.47 (C-4a), 160.13 (C-6), 164.08–167.16 (d, J = 246 Hz, C-3⁰),

177.18 (C-8).

7.19 (d, 1H, J = 8.2 Hz, H₃), 7.48 (t, 1H, J = 8.2 Hz, H₄), 7.49 (d,

1H, J = 8.2 Hz, H₆), 7.58 (d, 1H, J = 9.1 Hz, H₄), 7.86 (dd, 1H,

J = 9.1, 2.6 Hz, H₃), 8.46 (d, 1H, J = 2.6 Hz, H₁), 8.87 (s, 1H, OH),

10.27 (s, 1H, NH). ¹³C NMR (75 MHz, DMSO-d₆) d ppm: 24.02

(CH₃), 55.76 (OCH₃), 111.96 (C-3⁰), 112.71 (C-1), 118.89 (C-4),

119.94 (C-1⁰), 120.15 (C-5⁰), 122.06 (C-8a), 125.26 (C-3), 131.06

(C-6⁰), 131.75 (C-4⁰), 135.89 (C-2), 138.81 (C-7), 147.00 (C-6),

151.05 (C-4a), 157.13 (C-2⁰), 168.56 (CO), 172.56 (C-8).

4.1.4.7. 6-Amino-2-(4-ﬂuorophenyl)-4H-chromen-4-one (3g). Brown

solid, yield: 94%, mol. wt: 255. Anal. Calcd for C₁₅H₁₀FNO₂: C, 70.58; H,

3.95; N, 5.49. Found: C, 70.38; H, 4.03; N, 5.42. ¹H NMR (300 MHz,

DMSO-d₆) d ppm: 7.08 (s, 1H, H₇), 7.45 (t, 2H, J = 8.8 Hz, H₃), 7.63

4.1.5.3. N-(3-Hydroxy-2-(3-methoxyphenyl)-4-oxo-4H-chromen-6-

yl)acetamide (4c). Orange solid, yield: 54%, mol. wt: 325. Anal. Calcd

for C₁₈H₁₅NO₅: C, 66.46; H, 4.65; N, 4.31. Found: C, 66.42; H, 4.61; N,

4.30. ¹H NMR (300 MHz, DMSO-d₆) d ppm: 2.09 (s, 3H, CH₃), 3.82 (s,

(dd, 1H, J = 9.0, 2.6 Hz, H₃), 7.82 (d, 1H, J = 2.6 Hz, H₁), 7.87 (d, 1H,

J = 9.0 Hz, H₄), 8.20 (dd, 2H, J = 8.8, 5.4 Hz, H₂). ¹³C NMR (75 MHz,

DMSO-d₆) d ppm: 106.56 (C-7), 115.81 (C-1), 116.16–116.46 (d,

J = 22.6 Hz, C-3⁰), 120.32 (C-4), 123.85 (C-4a), 127.47 (C-3), 127.60 (C-

1⁰), 129.10–129.22 (d, J = 9.0 Hz, C-2⁰), 133.34 (C-2), 153.09 (C-4a),

161.86 (C-6), 162.59–165.91 (d, J = 250.00 Hz, C-4⁰), 176.55 (C-8).

3H, OCH₃), 7.09 (br d, 1H, J = 8.6 Hz, H₄), 7.47 (t, 1H, J = 8.6 Hz, H₅),

7.73 (d, 1H, J = 9.0 Hz, H₄), 7.75 (t, 1H, J = 1.8 Hz, H₂), 7.77 (br d, 1H,

J = 8.6 Hz, H₆), 7.92 (dd, 1H, J = 9.0, 2.5 Hz, H₃), 8.45 (d, 1H, J = 2.5 Hz,

H₁). ¹³C NMR (75 MHz, DMSO-d₆) d ppm: 24.05 (CH₃), 55.36 (OCH₃),

112.71 (C-1), 113.46 (C-2⁰), 115.31 (C-4⁰), 119.05 (C-4), 120.10 (C-6⁰),

121.37 (C-8a), 125.76 (C-3), 129.77 (C-5⁰), 132.65 (C-1⁰), 136.09 (C-2),

138.97 (C-7), 144.86 (C-6), 150.68 (C-4a), 159.25 (C-3⁰), 168.82 (CO),

172.94 (C-8).

4.1.4.8. 6-Amino-2-(3-(triﬂuoromethyl)phenyl)-4H-chromen-4-

one (3h). Brown solid, yield: 96%, mol. wt: 305. Anal. Calcd for

₁₆H₁₀F₃NO₂: C, 62.96; H, 3.30; N, 4.59. Found: C, 62.89; H, 3.35;

N, 4.42. ¹H NMR (300 MHz, DMSO-d₆) d ppm: 7.06 (s, 1H, H₇),

7.11 (dd, 1H, J = 8.9, 2.6 Hz, H₃), 7.13 (d, 1H, J = 2.6 Hz, H₁), 7.57

(d, 1H, J = 8.9 Hz, H₄), 7.80 (t, 1H, J = 7.9 Hz, H₅), 7.94 (t, 1H,

4.1.5.4. N-(3-Hydroxy-2-(4-methoxyphenyl)-4-oxo-4H-chromen-6-

yl)acetamide (4d). Orange solid, yield: 45%, mol. wt: 325. Anal. Calcd

for C₁₈H₁₅NO₅: C, 66.46; H, 4.65; N, 4.31. Found: C, 66.41; H, 4.64; N,

4.22. ¹H NMR (300 MHz, DMSO-d₆) d ppm: 2.09 (s, 3H, CH₃), 3.85 (s,

J = 7.9 Hz, H₄), 8.35 (br s, 1H, H₂), 8.36 (br d, 1H, J = 7.9 Hz, H₆).

¹³C NMR (75 MHz, DMSO-d₆) d ppm: 105.31 (C-1), 106.98 (C-7),

119.38 (C-4), 122.82 (q, J = 3.8 Hz, C-2⁰), 122.26 (C-3), 124.43 (C-

8a), 124.05 (q, J = 270.00 Hz, CF₃), 127.92 (q, J = 3.8 Hz, C-4⁰),

130.11 (q, J = 32.4 Hz, C-3⁰), 130.31 (C-5⁰), 130.48 (C-6⁰), 133.02

(C-1⁰), 146.57 (C-2), 160.07 (C-6), 148.25 (C-4a), 177.34 (C-8).

3H, OCH₃), 7.12 (m, 2H, H₃), 7.71 (d, 1H, J = 9.1 Hz, H₄), 7.88 (dd, 1H,

J = 2.5, 9.1 Hz, H₃), 8.19 (d, 2H, J = 9.1 Hz, H₂), 8.41 (d, 1H, H₁), 9.40

(s, OH), 10.26 (s, NH). ¹³C NMR (75 MHz, DMSO-d₆) d ppm: 24.17

(CH₃), 55.53 (OCH₃), 112.81 (C-1), 113.22 (C-3⁰), 118.98 (C-4),

123.26 (C-8a), 124.43 (C-1⁰), 125.43 (C-3), 129.53 (C-2⁰), 136.06 (C-

2), 138.05 (C-7), 145.65 (C-6), 150.62 (C-4a), 160.58 (C-4⁰), 168.70

(CO), 172.62 (C-8).

4.1.4.9. 6-Amino-2-(4-(triﬂuoromethyl)phenyl)-4H-chromen-4-

one (3i). Brown solid, yield: 95%, mol. wt: 305. Anal. Calcd for

₁₆H₁₀F₃NO₂: C, 62.96; H, 3.30; N, 4.59. Found: C, 62.88; H, 3.31;

N, 4.52. ¹H NMR (300 MHz, DMSO-d₆) d ppm: 7.08 (s, 1H, H₇),

7.29 (dd, 1H, J = 2.5, 9.1 Hz, H₃), 7.36 (d, 1H, J = 2.5 Hz, H₁), 7.65

4.1.5.5. N-(2-(2-Fluorophenyl)-3-hydroxy-4-oxo-4H-chromen-

6-yl)acetamide (4e). White solid, yield: 52%, mol. wt: 313, mp:

210 °C. Anal. Calcd for C₁₇H₁₂FNO₄: C, 65.18; H, 3.86; N, 4.47.

Found: C, 65.11; H, 3.89; N, 4.43. ¹H NMR (300 MHz, DMSO-d₆) d

(d, 2H, J = 9.1 Hz, H₄), 7.93 (d, 2H, J = 8.8 Hz, H₃), 8.29 (d, 2H,

J = 8.8 Hz, H₂). ¹³C NMR (75 MHz, DMSO-d₆) d ppm: 107.46 (C-7),

108.75 (C-1), 119.59 (C-4), 124.06 (C-3), 124.17 (C-8a), 124.81 (q,

J = 272 Hz, CF₃), 125.98 (q, J = 3.8 Hz, C-3⁰), 130.95 (C-2⁰), 129.25

(q, J = 32.4 Hz, C-4⁰), 135.40 (C-1⁰), 142.06 (C-2), 149.80 (C-4a),

160.07 (C-6), 176.98 (C-8).

ppm: 2.10 (s, 3H, CH₃), 7.37 (m, 1H, H₅), 7.42 (m, 1H, H₃), 7.59

(m, 1H, H₄), 7.62 (d, 1H, J = 8.8 Hz, H₄), 7.75 (td, 1H, J = 7.6,

2.2 Hz, H₆), 7.88 (dd, 1H, J = 2.7, 8.8 Hz, H₃), 8.48 (d, 1H,

J = 8.8 Hz, H₁), 9.36 (s, 1H, OH), 10.28 (s, 1H, NH). ¹³C NMR

(75 MHz, DMSO-d₆) d ppm: 24.03 (CH₃), 112.72 (C-1), 116.03–

116.31 (d, J = 21.1 Hz, C-3⁰), 118.95 (C-4), 118.95–119.16

(J = 14.3 Hz, C-1⁰), 121.96 (C-8a), 124.40 (C-5⁰), 125.57 (C-3),

131.22 (C-6⁰), 132.42–132.54 (d, J = 9.0 Hz, C-4⁰), 136.08 (C-2),

139.22 (C-7), 143.36 (C-6), 151.05 (C-4a), 157.52–160.85 (d,

J = 251.00 Hz, C-2⁰), 168.61 (CO), 172.61 (C-8).

4.1.5. General procedure for synthesis of ﬂavonols (4a–i)

Chalcones 1a–i (10 mmol) was solubilized in EtOH (50 mL),

then was added NaOH 5% (40 mL) and H₂O₂25% (10 mL). The solu-

tion was stirred overnight at rt and put onto water (100 mL) and

acidiﬁed with 2 M HCl. The yellow precipitate obtained was ﬁl-

tered, washed with water and dried to give 4a–i.

G. Casano et al. / Bioorg. Med. Chem. 18 (2010) 6012–6023

6019

4.1.5.6. N-(2-(3-Fluorophenyl)-3-hydroxy-4-oxo-4H-chromen-

6-yl)acetamide (4f). Yellow solid, yield: 45%, mol. wt: 313. Anal.

Calcd for C₁₇H₁₂FNO₄: C, 65.18; H, 3.86; N, 4.47. Found: C, 65.17;

H, 3.79; N, 4.42. ¹H NMR (300 MHz, DMSO-d₆) d ppm: 2.10 (s,

4.1.6.1. 6-Amino-3-hydroxy-2-phenyl-4H-chromen-4-one (5a). White

solid, yield: 94%, mol. wt: 253. Anal. Calcd for C₁₅H₁₁NO₃: C, 71.14; H,

4.38; N, 5.53. Found: C, 71.11; H, 4.42; N, 5.49. ¹H NMR (300 MHz,

DMSO-d₆) d ppm: 7.10 (dd, 1H, J = 8.9, 2.6 Hz, H₃), 7.18 (d, 1H,

3H, CH₃), 7.10 (br s, 1H, NH), 7.33 (td, 1H, J = 8.5, 2.3 Hz, H₄),

J = 2.6 Hz, H₁), 7.48 (d, 1H, J = 8.9 Hz, H₄), 7.50 (m, 1H, H ), 7.55 (m, 2H,

7.60 (td, 1H, J = 8.0, 6.3 Hz, H₅), 7.73 (d, 1H, J = 9.1 Hz, H₄), 7.92

H ), 8.17 (m, 2H, H ), 9.27 (s, 1H, OH). ¹³C NMR (75 MHz, DMSO-d₆) d

(dd, 1H, J = 9.1, 2.5 Hz, H₃), 8.02 (dt, 1H, J = 11.1, 1.8 Hz, H₂), 8.07

ppm: 55.71 (OCH₃), 104.22 (C-1), 111.92 (C-3⁰), 118.82 (C-4), 120.35

(C-1⁰), 120.10 (C-5⁰), 121.95 (C-3), 122.81 (C-8a), 131.02 (C-6⁰), 131.51

(C-4⁰), 138.21 (C-7), 145.73 (C-2), 146.36 (C-6), 147.79 (C-4a), 157.10

(C-2⁰), 172.41 (C-8).

(br d, 1H, J = 8.0 Hz, H₆), 8.45 (d, 1H, J = 2.5 Hz, H₁). ¹³C NMR

(75 MHz, DMSO-d₆) d ppm: 23.99 (CH₃), 112.59 (C-1), 114.24–

114.30 (d, J = 24.1 Hz, C-2⁰), 116.65–116.71 (d, J = 20.4 Hz, C-4⁰),

118.99 (C-4), 121.31 (C-6⁰), 123.59 (C-8a), 125.81 (C-3), 130.59–

130.70 (d, J = 8.3 Hz, C-5⁰), 133.55–133.67 (d, J = 8.9 Hz, C-1⁰),

136.10 (C-2), 139.32 (C-7), 143.39 (C-6), 150.58 (C-4a), 160.43–

163.64 (d, J = 242 Hz, C-3⁰), 168.67 (CO), 177.97 (C-8).

4.1.6.2.

6-Amino-3-hydroxy-2-(2-methoxyphenyl)-4H-chromen-4-

one (5b). White solid, yield: 98%, mol. wt: 283. Anal. Calcd for

C₁₆H₁₃NO₄: C, 67.84; H, 4.63; N, 4.94. Found: C, 67.78; H, 4.65; N, 4.91.

¹H NMR (300 MHz, DMSO-d₆) d ppm: 3.78 (s, 3H, OCH_3–2), 5.45 (br s,

4.1.5.7. N-(2-(4-Fluorophenyl)-3-hydroxy-4-oxo-4H-chromen-

6-yl)acetamide (4g). Yellow solid, yield: 40%, mol. wt: 313. Anal.

Calcd for C₁₇H₁₂FNO₄: C, 65.18; H, 3.86; N, 4.47. Found: C, 65.12;

H, 3.89; N, 4.41. ¹H NMR (300 MHz, DMSO-d₆) d ppm: 2.08 (s,

2H, NH₂), 7.05 (dd, 1H, J = 8.9, 2.5 Hz, H₃), 7.06 (t, 1H, J = 8.2 Hz, H ),

7.16 (d, 1H, J = 8.2 Hz, H ), 7.18 (d, 1H, J = 2.5 Hz, H₁), 7.33 (d, 1H,

J = 8.9 Hz, H₄), 7.49 (t, 1H, J = 8.2 Hz, H ), 7.44 (d, 1H, J = 8.2 Hz, H ),

8.54 (br s, 1H, OH). ¹³C NMR (75 MHz, DMSO-d₆) d ppm: 112.63 (C-1),

113.29 (C-2⁰), 115.06 (C-4⁰), 119.34 (C-6⁰), 119.95 (C-4), 121.96 (C-8a),

125.71 (C-3), 129.64 (C-5⁰), 131.58 (C-2), 132.78 (C-1⁰), 138.60 (C-7),

144.46 (C-6), 148.72 (C-4a), 159.16 (C-3⁰), 172.58 (C-8).

3H, CH₃), 7.40 (t, 2H, J = 9.0 Hz, H₃), 7.71 (d, 1H, J = 9.0 Hz, H₄),

7.91 (dd, 1H, J = 9.0, 2.5 Hz, H₃), 8.27 (dd, 2H, J = 9.0, 5.4 Hz, H₂),

8.44 (d, 1H, J = 2.5 Hz, H₁), 10.35 (s, 1H, NH). ¹³C NMR (75 MHz,

DMSO-d₆) d ppm: 24.00 (CH₃), 112.63 (C-1), 115.48–115.76 (d,

J = 21.0 Hz, C-3⁰), 118.90 (C-4), 121.37 (C-8a), 125.55 (C-3),

128.00 (C-1⁰), 130.01–130.12 (d, J = 8.0 Hz, C-2⁰), 136.01 (C-2),

138.86 (C-7), 144.28 (C-6), 150.55 (C-4a), 160.95–164.24 (d,

J = 247.00 Hz, C-4⁰), 168.62 (CO), 173.00 (C-8).

4.1.6.3. 6-Amino-3-hydroxy-2-(3-methoxyphenyl)-4-oxo-4H-chromen-

4-one (5c). White solid, yield: 98%, mol. wt: 283, mp: 152.7 °C. Anal. Calcd

for C₁₆H₁₃NO₄: C, 67.84; H, 4.63; N, 4.94. Found: C, 67.81; H, 4.71; N, 4.87.

¹H NMR (300 MHz, DMSO-d₆) d ppm: 2.09 (s, 3H, CH₃), 3.86 (s, 3H, OCH₃),

7.09 (br d, 1H, J = 8.6 Hz, H ), 7.47 (t, 1H, J = 8.6 Hz, H ), 7.50 (d, 1H,

4.1.5.8. N-(3-Hydroxy-4-oxo-2-(3-(triﬂuoromethyl)phenyl)-4H-

chromen-6-yl)acetamide (4h). Yellow solid, yield: 26%, mol. wt:

363. Anal. Calcd for C₁₈H₁₂F₃NO₄: C, 59.51; H, 3.33; N, 3.86. Found:

C, 59.45; H, 3.35; N, 3.83. ¹H NMR (300 MHz, DMSO-d₆) d ppm:

2.08 (s, 3H, CH₃), 7.76 (d, 1H, J = 8.9 Hz, H₄), 7.80 (t, 1H,

J = 9.0 Hz, H₄), 7.75 (t, 1H, J = 1.8 Hz, H ), 7.77 (br d, 1H, J = 8.6 Hz, H ),

2 6

7.15 (dd, 1H, J = 9.0, 2.5 Hz, H₃), 7.05 (d, 1H, J = 2.5 Hz, H₁). ¹³C NMR

(75 MHz, DMSO-d₆) d ppm: 55.36 (OCH₃), 104.21 (C-1), 114.01 (C-3 ),

118.79, (C-4), 122.06 (C-3, C-8a), 124.05 (C-1 ), 129.22 (C-2 ), 137.41 (C-

7), 144.89 (C-2), 145.82, (C-6), 147.19 (C-4a), 160.24 (C-4 ), 172.38 (C-8).

J = 8.2 Hz, H₅), 7.85 (br d, 1H, J = 8.2 Hz, H₄), 7.91 (dd, 1H, J = 8.9,

2.6 Hz, H₃), 8.42 (d, 1H, J = 2.6 Hz, H₁), 8.46 (br d, 1H, J = 8.2 Hz,

4.1.6.4. 6-Amino-3-hydroxy-2-(4-methoxyphenyl)-4H-chromen-4-one

(5d). White solid, yield: 97%, mol. wt: 283. Anal. Calcd for C₁₆H₁₃NO₄: C,

67.84; H, 4.63; N, 4.94. Found: C, 67.83; H, 4.68; N, 4.89. ¹H NMR

(300 MHz, DMSO-d₆) d ppm: 3.83 (s, 3H, OCH₃), 5.44 (s, NH₂), 7.06 (dd,

H₆), 8.54 (br s, 1H, H₂), 9.93 (br s, 1H, OH), 10.25 (s, 1H, NH).

¹³C NMR (75 MHz, DMSO-d₆) d ppm: 23.98 (CH₃), 112.57 (C-1),

119.04 (C-4), 121.36 (C-8a), 123.42 (q, J = 270.00 Hz, CF₃), 123.96

(q, J = 3.8 Hz, C-2⁰), 125.73 (C-3), 126.03 (q, J = 3.8 Hz, C-4⁰),

129.33 (q, J = 31.7 Hz, C-3⁰), 129.78 (C-5⁰), 131.10 (C-6⁰), 132.45

(C-1⁰), 136.07 (C-2), 139.44 (C-7), 143.11 (C-6), 150.59 (C-4a),

168.55 (CO), 172.95 (C-8).

1H, J = 8.9, 2.6 Hz, H₃), 7.10 (d, 2H, J = 8.9 Hz, H ) 7.12 (d, 1H, J = 2.6 Hz,

H₁), 7.45 (d, 1H, J = 8.9 Hz, H₄), 8.15 (d, 2H, J = 8.9 Hz, H ). ¹³C NMR

(75 MHz, DMSO-d₆) d ppm: 55.36 (OCH₃), 104.21 (C-1), 114.01 (C-3 ),

118.79 (C-4), 122.06 (C-3, C-8a), 124.05 (C-1⁰), 129.22 (C-2 ), 137.41 (C-

7), 144.89 (C-2), 145.82 (C-6), 147.19 (C-4a), 160.24 (C-4 ), 172.38 (C-8).

4.1.5.9. N-(3-Hydroxy-4-oxo-2-(3-(triﬂuoromethyl)phenyl)-4H-

chromen-6-yl)acetamide (4i). Yellow solid, yield: 30%, mol. wt:

363. Anal. Calcd for C₁₈H₁₂F₃NO₄: C, 59.51; H, 3.33; N, 3.86. Found:

C, 59.43; H, 3.38; N, 3.82. ¹H NMR (300 MHz, DMSO-d₆) d ppm:

2.09 (s, 3H, CH₃), 7.73 (d, 1H, J = 8.9 Hz, H₄), 7.90 (dd, 1H, J = 2.5,

4.1.6.5. 6-Amino-2-(2-ﬂuorophenyl)-3-hydroxy-4H-chromen-4-

one (5e). White solid, yield: 98%, mol. wt: 271, mp: 198.9 °C. Anal.

Calcd for C₁₅H₁₀FNO₃: C, 66.42; H, 3.72; N, 5.16. Found: C, 66.38; H,

3.74; N, 5.12. ¹H NMR (300 MHz, DMSO-d₆) d ppm: 5.48 (s, 2H,

NH₂), 7.07 (dd, 1H, J = 2.7, 8.8 Hz, H₃), 7.16 (d, 1H, J = 2.7 Hz, H₁),

8.9 Hz, H₃), 7.92 (d, 2H, J = 8.9 Hz, H₃), 8.40 (d, 2H, J = 8.9 Hz,

H₂), 8.44 (d, 1H, J = 2.5 Hz, H₁), 9.98 (s, 1H, OH), 10.26 (s, 1H,

7.35 (m, 2H, H_{5 ,3}), 7.39 (d, 1H, J = 8.8 Hz, H₄), 7.58 (m, 1H, H₄),

NH). ¹³C NMR (75 MHz, DMSO-d₆) d ppm: 24.19 (CH₃), 112.76

(C-1), 119.21 (C-4), 121.53 (C-8a), 124.68 (q, J = 272.0 Hz, CF₃),

125.59 (q, J = 3.8 Hz, C-3⁰), 126.02 (C-3), 128.31 (C-2⁰), 130.50 (q,

J = 32.4 Hz, C-4⁰), 135.58 (C-1⁰)136.32 (C-2), 150.82 (C-4a), 143.41

(C-6), 168.76 (CO), 172.65 (C-8).

7.73 (td, 1H, J = 2.2, 7.6 Hz, H₆), 8.72 (s, 1H, OH). ¹³C NMR

(75 MHz, DMSO-d₆)

d ppm: 104.14 (C-1), 116.96–116.25 (d,

J = 21.8 Hz, C-3⁰), 118.85 (C-4), 119.30–119.41 (d, J = 14.3 Hz, C-

1⁰), 122.27 (C-3), 122.70 (C-8a), 124.36–124.38 (d, J = 3.5 Hz, C-

5⁰), 131.19 (C-6⁰), 132.17–132.28 (d, J = 8.6 Hz, C-4⁰), 138.57 (C-7),

142.76 (C-6), 145.95 (C-2), 147.75 (C-4a), 157.49–160.82 (d,

J = 251.00 Hz, C-2⁰), 172.41 (C-8).

4.1.6. General procedure for deprotection of acetamido

derivatives (5a–i)

Flavonol 4a–i (10 mmol) was added to a solution of EtOH

(20 mL) and H₂SO₄concd (5 mL). The solution was submitted to

MWI in open vessel 80 °C, 2 + 20 min, upon cooling the solvent

was removed under vacuo and the residue obtain is poured onto

ice water (100 mL). Then the solution was neutralized with NH₄OH

16% until pH 7. The red precipitate formed was collected by ﬁltra-

tion and washed with excess cold water. Amino compound was ob-

tained as a red powder without further puriﬁcation.

4.1.6.6. 6-Amino-2-(3-ﬂuorophenyl)-3-hydroxy-4H-chromen-4-

one (5f). White solid, yield: 96%, mol. wt: 271. Anal. Calcd for

C₁₅H₁₀FNO₃: C, 66.42; H, 3.72; N, 5.16. Found: C, 66.39; H, 3.73;

N, 5.11. ¹H NMR (300 MHz, DMSO-d₆) d ppm: 7.10 (dd, 1H,

J = 9.0, 2.7 Hz, H₃), 7.15 (d, 1H, J = 2.7 Hz, H₁), 7.32 (td, 1H, J = 8.5,

2.3 Hz, H₄), 7.50 (d, 1H, J = 9.0 Hz, H₄), 7.59 (td, 1H, J = 8.0,

6.3 Hz, H₅), 7.98 (dt, 1H, J = 11.1, 1.8 Hz, H₂), 8.04 (br d, 1H,

J = 8.0 Hz, H₆). ¹³C NMR (75 MHz, DMSO-d₆) d ppm: 103.93 (C-1),

6020

G. Casano et al. / Bioorg. Med. Chem. 18 (2010) 6012–6023

113.83–114.15 (d, J = 24.1 Hz, C-2⁰), 116.14–116.41 (d, J = 20.4 Hz,

C-4⁰), 118.96 (C-4), 122.06 (C-8a), 122.54 (C-3), 123.40 (C-6⁰),

130.50–130.61 (d, J = 8.3 Hz, C-5⁰), 133.88–133.99 (d, J = 8.3 Hz,

C-1⁰), 138.71 (C-7), 142.80 (C-6), 145.96 (C-2), 147.26 (C-4a),

160.41–163.63 (d, J = 243 Hz, C-3⁰), 172.71 (C-8).

4.1.7.2.

N-(3-Methoxy-2-(2-methoxyphenyl)-4-oxo-4H-chro-

men-6-yl)acetamide (6b). White solid, yield: 88%, mol. wt: 339.

Anal. Calcd for C₁₉H₁₇NO₅: C, 67.25; H, 5.05; N, 4.13. Found: C,

67.22; H, 5.12; N, 4.09. ¹H NMR (300 MHz, DMSO-d₆) d ppm:

2.08 (s, 2H, CH₃), 3.71 (s, 3H, OCH_3–7), 3.81 (s, 3H, OCH_3–2), 7.09

(t, 1H, J = 8.2 Hz, H₅), 7.19 (d, 1H, J = 8.2 Hz, H₃), 7.54 (t, 1H,

4.1.6.7. 6-Amino-2-(4-ﬂuorophenyl)-3-hydroxy-4-oxo-4H-chro-

men-4-one (5g). Brown solid, yield: 96%, mol. wt: 271. Anal. Calcd

for C₁₅H₁₀FNO₃: C, 66.42; H, 3.72; N, 5.16. Found: C, 66.41; H, 3.63;

N, 5.12. ¹H NMR (300 MHz, DMSO-d₆) d ppm: 7.42 (t, 2H, J = 8.9 Hz,

J = 8.2 Hz, H₄), 7.49 (d, 1H, J = 8.2 Hz, H₆), 7.59 (d, 1H, J = 9.1 Hz,

H₄), 7.92 (dd, 1H, J = 9.1, 2.6 Hz, H₃), 8.42 (d, 1H, J = 2.6 Hz, H₁),

10.29 (s, 1H, NH). ¹³C NMR (75 MHz, DMSO-d₆) d ppm: 24.01

(CH₃), 55.68 (OCH_3–2), 59.66 (OCH_3–8), 111.74 (C-3⁰), 112.92 (C-

H₃), 7.60 (dd, 1H, J = 9.0, 2.4 Hz, H₃), 7.88 (d, 1H, J = 2.4 Hz, H₁),

1), 118.92 (C-4), 119.70 (C-1⁰), 120.25 (C-5⁰), 124.08 (C-8a),

125.47 (C-3), 130.44 (C-6⁰), 132.08 (C-4⁰), 136.37 (C-2), 140.85

(C-6), 151.04 (C-4a), 155.67 (C-7), 156.89 (C-2⁰), 168.60 (CO),

173.39 (C-8).

7.84 (d, 1H, J = 9.0 Hz, H₄), 8.28 (dd, 2H, J = 8.9, 5.4 Hz, H₂). ¹³C

NMR (75 MHz, DMSO-d₆) d ppm: 115.70 (C-1), 115.56–115;85 (d,

J = 22.0 Hz, C-3⁰), 120.23 (C-4), 121.86 (C-8a), 127.24 (C-3),

127.70–127.74 (d, J = 2.5 Hz, C-1⁰), 130.21–130.30 (d, J = 8.0 Hz,

C-2⁰), 132.48 (C-2), 138.80 (C-7), 144.85 (C-6), 152.09 (C-4a),

161.08–164.38 (d, J = 249.00 Hz, C-4⁰), 172.43 (C-8).

4.1.7.3.

N-(3-Methoxy-2-(3-methoxyphenyl)-4-oxo-4H-chro-

men-6-yl)acetamide (6c). Pale yellow solid, yield: 84%, mol. wt:

339. Anal. Calcd for C₁₉H₁₇NO₅: C, 67.25; H, 5.05; N, 4.13. Found:

C, 67.24; H, 5.11; N, 4.11. ¹H NMR (300 MHz, DMSO-d₆) d ppm:

4.1.6.8. 6-Amino-3-hydroxy-2-(3-(triﬂuoromethyl)phenyl)-4H-

chromen-4-one (5h). Pale brown solid, yield: 94%, mol. wt: 321.

Anal. Calcd for C₁₆H₁₀F₃NO₃: C, 59.82; H, 3.14; N, 4.36. Found: C,

59.76; H, 3.16; N, 4.34. ¹H NMR (300 MHz, DMSO-d₆) d ppm:

7.27 (dd, 1H, J = 2.8, 9.1 Hz, H₃), 7.39 (d, 1H, J = 2.8 Hz, H₁), 7.63

2.10 (s, 3H, CH₃), 3.82 (s, 3H, OCH_3–3), 3.85 (s, 3H, OCH_3–7), 7.16

(dd, 1H, J = 8.0, 2.0 Hz, H₄), 7.50 (t, 1H, J = 8.0 Hz, H₅), 7.57 (t,

1H, J = 2.0 Hz, H₂), 7.62 (br d, 1H, J = 8.0 Hz, H₆), 7.72 (d, 1H,

J = 9.1 Hz, H₄), 7.94 (dd, 1H, J = 9.1, 2.5 Hz, H₃), 8.38 (d, 1H,

J = 2.5 Hz, H₁), 10.27 (br s, 1H, NH). ¹³C NMR (75 MHz, DMSO-d₆)

(d, 1H, J = 9.1 Hz, H₄), 7.80 (t, 1H, J = 8.2 Hz, H_{5 ), 7.85 (d, 1H, J = 8.2 Hz,}

H₄), 8.45 (d, 1H, J = 8.2 Hz, H₆), 8.52 (br s, 1H, H₂), 9.75 (s, 1H,

OH). ¹³C NMR (75 MHz, DMSO-d₆) d ppm: 108.11 (C-1), 119.67

(C-4), 122.21 (C-8a), 123.42 (q, J = 270.00 Hz, CF₃), 124.07 (q,

J = 3.8 Hz, C-2⁰), 124.42 (C-3), 126.13 (q, J = 3.8 Hz, C-4⁰), 129.51

(q, J = 31.7 Hz, C-3⁰), 130.00 (C-5⁰), 131.27 (C-6⁰), 132.81 (C-1⁰),

139.35 (C-7), 141.61 (C-2), 143.09 (C-6), 149.14 (C-4a), 172.88

(C-8).

d ppm: 23.98 (CH₃), 55.29 (OCH_3–3), 55.29 (OCH_3–7), 112.83 (C-

1), 113.78 (C-2⁰), 116.33 (C-4⁰), 119.00 (C-4), 120.52 (C-6⁰),

123.67 (C-8a), 125.60 (C-3), 129.83 (C-5⁰), 131.72 (C-1⁰), 136.40

(C-2), 154.57 (C-7), 140.53 (C-6), 150.61 (C-4a), 159.17 (C-3⁰),

168.57 (CO), 173.71 (C-8).

4.1.7.4.

N-(3-Methoxy-2-(4-methoxyphenyl)-4-oxo-4H-chro-

men-6-yl)acetamide (6d). White solid, yield: 91%, mol. wt: 339.

Anal. Calcd for C₁₉H₁₇NO₅: C, 67.25; H, 5.05; N, 4.13. Found: C,

67.21; H, 5.08; N, 4.08. ¹H NMR (300 MHz, DMSO-d₆) d ppm:

4.1.6.9. 6-Amino-3-hydroxy-4-oxo-2-(4-(triﬂuoromethyl)phe-

nyl)-4H-chromen-4-one (5i). Pale brown solid, yield: 95%, mol.

wt: 321. Anal. Calcd for C₁₆H₁₀F₃NO₃: C, 59.82; H, 3.14; N, 4.36.

Found: C, 59.83; H, 3.18; N, 4.28. ¹H NMR (300 MHz, DMSO-d₆) d

ppm: 7.49 (dd, 1H, J = 2.6 Hz, 9.1 Hz, H₃), 7.71 (d, 1H, J = 2.6 Hz,

2.09 (s, CH₃), 3.79 (s, OCH_3–7), 3.86 (s, OCH_3–4), 7.14 (d, 2H,

J = 8.8 Hz, H₃), 7.70 (d, 1H, J = 9.0 Hz, H₄), 7.93 (dd, 1H, J = 9.0,

2.3 Hz, H₃), 8.05 (d, 2H, J = 8.8 Hz, H₂), 8.36 (d, 1H, J = 2.3 Hz, H₁),

H₁), 7.76 (d, 1H, J = 9.1 Hz, H₄), 7.93 (d, 2H, J = 8.5 Hz, H₃), 8.41

10.29 (s, NH). ¹³C NMR (75 MHz, DMSO-d₆) d ppm: 23.98 (CH₃),

(d, 2H, J = 8.5 Hz, H₂). ¹³C NMR (75 MHz, DMSO-d₆) d ppm:

55.41 (OCH_3–4), 59.45 (OCH_3–7), 112.89 (C-1), 114.17 (C-3⁰),

113.08 (C-1), 120.17 (C-4), 122.08 (C-8a), 124.81 (q, J = 272 Hz,

CF₃), 125.70 (q, J = 3.8 Hz, C-3⁰), 126.58 (C-3), 128.39 (C-2⁰),

129.50 (q, J = 32.4 Hz, C-4⁰), 135.48 (C-1⁰; C-2), 140.04 (C-7),

143.58 (C-6), 151.22 (C-4a), 172.91 (C-8).

118.81 (C-4), 122.64 (C-1⁰), 123.66 (C-8a), 125.40 (C-3), 130.00

(C-2⁰), 136.30 (C-2), 139.75 (C-6), 150.49 (C-4a), 154.79 (C-7),

161.17 (C-4⁰), 168.85 (CO), 173.47 (C-8).

4.1.7.5. N-(2-(2-Fluorophenyl)-3-methoxy-4-oxo-4H-chromen-

6-yl)acetamide (6e). Yellow solid, yield: 82%, mol. wt: 327. Anal.

Calcd for C₁₈H₁₄FNO₄: C, 66.05; H, 4.31; N, 4.28. Found: C, 65.98;

H, 4.33; N, 4.23. ¹H NMR (300 MHz, DMSO-d₆) d ppm: 2.10 (s,

4.1.7. General procedure for methylation of compounds (6a–i)

Flavonol 2a–i (10 mmol) was solubilized in acetone (20 mL)

with K₂CO₃(1 equiv), then dimethyl sulfate (1 equiv) was intro-

duced and the solution was heated at 50 °C for 6 h. The reaction

was monitored by TLC and when no more beginning product ap-

peared, the solvent was removed under reduce pressure. The mix-

ture obtained was poured onto water (100 mL) and the pH was

adjusted to 7. The precipitate obtained was ﬁltered off and washed

with water and dried to afford methoxyﬂavones 6a–i.

3H, CH₃), 3.77 (s, 3H, OCH₃), 7.40 (m, 2H, H_{3 ,5}), 7.63 (m, 1H, H₄),

7.64 (d, 1H, J = 8.8 Hz, H₄), 7.73 (td, 1H, J = 2.2, 7.6 Hz, H₆), 7.94

(dd, 1H, J = 2.7, 8.8 Hz, H₃), 8.42 (d, 1H, J = 2.7 Hz, H₁), 10.29 (s,

1H, NH). ¹³C NMR (75 MHz, DMSO-d₆) d ppm: 24.16 (CH₃), 60.06

(OCH_3–7), 113.08 (C-1), 116.14–116.42 (d, J = 21.1 Hz, C-3⁰),

118.68–118.87 (d, J = 14.3 Hz, C-1⁰), 119.12 (C-4), 124.16 (C-8a),

124.84 (C-5⁰), 125.88 (C-3), 131.27 (C-6⁰), 133.12–133.23 (d,

J = 6.8 Hz, C-4⁰), 136.71 (C-2), 141.19 (C-6), 151.14 (C-4a), 152.09

(C-7), 157.69–161.00 (d, J = 249.00 Hz, C-2⁰), 168.79 (CO), 173.51

(C-8).

4.1.7.1. N-(3-Methoxy-4-oxo-2-phenyl-4H-chromen-6-yl)acet-

amide (6a). Yellow solid, yield: 86%, mol. wt: 309. Anal. Calcd for

₁₈H₁₅NO₄: C, 69.89; H, 4.89; N, 4.53. Found: C, 69.83; H, 4.92;

N, 4.49. ¹H NMR (300 MHz, DMSO-d₆) d ppm: 2.08 (s, 3H, CH₃),

4.1.7.6. N-(2-(3-Fluorophenyl)-3-methoxy-4-oxo-4H-chromen-

6-yl)acetamide (6f). Yellow solid, yield: 71%, mol. wt: 327. Anal.

Calcd for C₁₈H₁₄FNO₄: C, 66.05; H, 4.31; N, 4.28. Found: C, 66.01;

H, 4.37; N, 4.24. ¹H NMR (300 MHz, DMSO-d₆) d ppm: 2.08 (s,

3.81 (s, 3H, OCH₃), 7.56 (m, 2H, H₃), 7.58 (m, 1H, H₄), 7.67 (d,

1H, J = 9.1 Hz, H₄), 7.94 (dd, 1H, J = 9.1, 2.5 Hz, H₃), 8.02 (m, 2H,

H₂), 8.37 (d, 1H, J = 2.5 Hz, H₁), 10.28 (s, 1H, NH). ¹³C NMR

(75 MHz, DMSO-d₆) d ppm: 24.01 (CH₃), 59.66 (OCH₃), 112.85 (C-

1), 118.89 (C-4), 123.69 (C-8a), 125.56 (C-3), 128.20 (C-2⁰),

128.63 (C-3⁰), 130.52 (C-1⁰), 130.78 (C-4⁰), 136.39 (C-2), 140.42

(C-6), 150.62 (C-4a), 154.79 (C-7), 168.55 (CO), 173.70 (C-8).

3H, CH₃), 3.83 (s, 3H, OCH₃), 7.41 (td, 1H, J = 8.5, 2.3 Hz, H₄), 7.62

(td, 1H, J = 8.0, 6.3 Hz, H₅), 7.70 (d, 1H, J = 9.0 Hz, H₄), 7.83 (dt,

1H, J = 11.1, 1.8 Hz, H₂), 7.89 (br d, 1H, J = 8.0 Hz, H₆), 7.93 (dd,

1H, J = 9.0, 2.5 Hz, H_{3) 8.36 (d, 1H, J = 2.5 Hz,}H₁). 10.26 (br s, 1H, NH).

G. Casano et al. / Bioorg. Med. Chem. 18 (2010) 6012–6023

6021

¹³C NMR (75 MHz, DMSO-d₆) d ppm: 24.16 (CH₃), 59.89 (OCH₃),

112.98 (C-1), 114.95–115.26. (d, J = 23.4 Hz, C-2⁰), 117.72–118.00

(d, J = 21.1 Hz, C-4⁰), 119.20 (C-4), 123.83 (C-8a), 124.60–124.64

(d, J = 3.0 Hz, C-6⁰), 125.89 (C-3), 130.95–131.05 (d, J = 7.5 Hz, C-

5⁰), 132.77–132.88 (d, J = 8.3 Hz, C-1⁰), 136.65 (C-2), 140.94 (C-6),

150.75 (C-4a), 153.25 (C-7), 160.51–163.74 (d, J = 243 Hz, C-3⁰),

168.78 (CO), 173.92 (C-8).

DMSO-d₆) d ppm: 59.61 (OCH₃), 105.55 (C-1), 119.00 (C-4), 122.56

(C-3), 124.46 (C-8a), 128.11 (C-2⁰), 128.62 (C-3⁰), 130.56 (C-1⁰), 130.85

(C-4⁰), 140.04 (C-6), 144.91 (C-2), 147.69 (C-4a), 154.33 (C-7) 173.62

(C-8).

4.1.8.2. 6-Amino-3-methoxy-2-(2-methoxyphenyl)-4H-chromen

-4-one (7b). Brown solid, yield: 76%, mol. wt: 297. Anal. Calcd for

₁₇H₁₅NO₄: C, 68.68; H, 5.09; N, 4.71. Found: C, 68.66; H, 5.13;

4.1.7.7. N-(2-(4-Fluorophenyl)-3-methoxy-4-oxo-4H-chromen-

6-yl)acetamide (6g). White solid, yield: 86%, mol. wt: 327. Anal.

Calcd for C₁₈H₁₄FNO₄: C, 66.05; H, 4.31; N, 4.28. Found: C, 66.07;

H, 4.32; N, 4.21. ¹H NMR (300 MHz, DMSO-d₆) d ppm: 2.07 (s,

N, 4.68. ¹H NMR (300 MHz, DMSO-d₆) d ppm: 3.74 (s, 3H, OCH_3–

₇), 3.81 (s, 3H, OCH_3–2), 5.51 (s, 2H, NH₂), 7.01 (dd, 1H, J = 2.8,

8.9 Hz, H₃), 7.03 (t, 1H, J = 7.6 Hz, H₅), 7.06 (d, 1H, J = 2.8 Hz, H₁),

7.28 (d, 1H, J = 8.9 Hz, H₃), 7.42 (dd, 1H, J = 1.7, 7.6 Hz, H₆), 7.44

3H, CH₃), 3.74 (s, 3H, OCH₃), 7.09 (t, 2H, J = 9.0 Hz, H₃), 7.37 (d,

(d, 1H, J = 2.8 Hz, H₄), 7.46 (t, 1H, J = 7.6 Hz, H₄). ¹³C NMR

1H, J = 9.2 Hz, H₄), 8.00 (d, 1H, J = 2.7 Hz, H₁), 8.01 (dd, 2H, J = 9.0,

(75 MHz, DMSO-d₆) d ppm: 59.78 (OCH_3–2), 60.13 (OCH_3–7),

5.4 Hz, H₂), 8.24 (dd, 1H, J = 9.2, 2.7 Hz, H₃), 9.54 (s, 1H, NH). ¹³C

107.06 (C-1), 111.22 (C-3⁰), 118.80 (C-4), 120.17 (C-5⁰), 120.25

(C-1⁰), 122.30 (C-3), 125.06 (C-8a), 130.39 (C-6⁰), 131.60 (C-4⁰),

141.06 (C-6), 143.93 (C-2), 149.25 (C-4a), 155.64 (C-7), 157.04

(C-2⁰), 174.48 (C-8).

NMR (75 MHz, DMSO-d₆) d ppm: 23.85 (CH₃), 59.61 (OCH₃),

113.96 (C-1), 115.17–115.46 (d, J = 21.9 Hz, C-3⁰), 118.02 (C-4),

123.74 (C-8a), 126.05 (C-3), 126.70 (C-1⁰), 130.32–130.44 (d,

J = 9.0 Hz, C-2⁰), 136.10 (C-2), 140.43 (C-6), 150.91 (C-4a), 154.18

(C-7), 161.83–165.17 (d, J = 252 Hz, C-4⁰), 168.95 (CO), 174.32 (C-8).

4.1.8.3. 6-Amino-3-methoxy-2-(3-methoxyphenyl)-4H-chromen

-4-one (7c). Yellow solid, yield: 91%, mol. wt: 297. Anal. Calcd for

4.1.7.8. N-(3-Methoxy-4-oxo-2-(3-(triﬂuoromethyl)phenyl)-4H-

chromen-6-yl)acetamide (6h). White solid, yield: 85%, mol. wt:

377. Anal. Calcd for C₁₉H₁₄F₃NO₄: C, 60.48; H, 3.74; N, 3.71. Found:

C, 60.45; H, 3.77; N, 3.68. ¹H NMR (300 MHz, DMSO-d₆) d ppm:

2.09 (s, 3H, CH₃), 3.84 (s, 3H, OCH₃), 7.72 (d, 1H, J = 9.2 Hz, H₄),

C₁₇H₁₅NO₄: C, 68.68; H, 5.09; N, 4.71. Found: C, 68.61; H, 5.14;

N, 4.69. ¹H NMR (300 MHz, DMSO-d₆) d ppm: 3.77 (s, 3H, OCH_3–

₇), 3.82 (OCH_3–3), 5.51 (s, 2H, NH₂), 7.07 (dd, 1H, J = 2.8, 8.9 Hz,

H₃), 7.12 (dd, 1H, J = 2.0, 8.0 Hz, H₄), 7.13 (d, 1H, J = 2.8 Hz, H₁),

7.46 (d, 1H, J = 8.9 Hz, H₄), 7.47 (t, 1H, J = 8.0 Hz, H₅), 7.53 (t, 1H,

7.82 (t, 1H, J = 8.4 Hz, H₅), 7.94 (br d, 1H, J = 8.4 Hz, H₄), 7.94

J = 2.0 Hz, H₂), 7.57 (d, 1H, J = 8.0 Hz, H₆). ¹³C NMR (75 MHz,

(dd, 1H, J = 9.2, 2.5 Hz, H₃), 8.31 (br d, 1H, J = 8.4 Hz, H₆), 8.32 (br

DMSO-d₆) d ppm: 55.44 (OCH_3–3), 59.78 (OCH_3–7), 104.55 (C-1),

s, 1H, H₂), 8.37 (d, 1H, J = 2.5 Hz, H₁), 10.28 (s, 1H, NH). ¹³C NMR

113.84 (C-2⁰), 116.22 (C-4⁰), 119.13 (C-4), 120.58 (C-6⁰), 122.24

(C-3), 124.66 (C-8a), 129.95 (C-5⁰), 132.31 (C-1⁰), 140.27 (C-6),

146.50 (C-2), 147.32 (C-4a), 154.14 (C-7), 159.31 (C-3⁰), 173.85 (C-8).

(75 MHz, DMSO-d₆) d ppm: 24.10 (CH₃), 59.76 (OCH₃) 112.80 (C-

1), 119.09 (C-4), 123.74 (C-8a), 123.42 (q, J = 270.00 Hz, CF₃),

124.69 (q, J = 3.8 Hz, C-2⁰), 125.73 (C-3), 127.22 (q, J = 3.8 Hz, C-

4⁰), 129.47 (q, J = 32.4 Hz, C-3⁰), 129.97 (C-5⁰), 131.60 (C-6⁰),

132.22 (C-1⁰), 136.55 (C-2), 152.99 (C-7), 140.85 (C-6), 150.64 (C-

4a), 168.63 (CO), 173.76 (C-8).

4.1.8.4. 6-Amino-3-methoxy-2-(4-methoxyphenyl)-4H-chromen

-4-one (7d). Yellow solid, yield: 93%, mol. wt: 297. Anal. Calcd for

₁₇H₁₅NO₄: C, 68.68; H, 5.09; N, 4.71. Found: C, 68.65; H, 5.09; N,

4.73. ¹H NMR (300 MHz, DMSO-d₆) d ppm: 3.78 (s, OCH_3–7), 3.85 (s,

4.1.7.9. N-(3-Methoxy-4-oxo-2-(4-(triﬂuoromethyl)phenyl)-4H-

chromen-6-yl)acetamide (6i). White solid, yield: 93%, mol. wt:

377. Anal. Calcd for C₁₉H₁₄F₃NO₄: C, 60.48; H, 3.74; N, 3.71. Found:

C, 60.43; H, 3.75; N, 3.63. ¹H NMR (300 MHz, DMSO-d₆) d ppm:

2.08 (s, 3H, CH₃), 3.83 (s, 3H, OCH₃), 7.70 (d, 1H, J = 9.1 Hz, H₄),

OCH_3–4), 7.13 (d, 2H, J = 8.8 Hz, H₃), 7.27 (dd, 1H, J = 8.9, 2.6 Hz,

H₃), 7.40 (d, 1H, J = 2.6 Hz, H₁), 7.59 (d, 1H, J = 8.9 Hz, H₄), 8.03

(d, 2H, J = 8.8 Hz, H₂). ¹³C NMR (75 MHz, DMSO-d₆) d ppm: 55.43

(OCH_3–4), 59.44 (OCH_3–7), 108.96 (C-1), 114.17 (C-3⁰), 119.31 (C-

4), 122.83 (C-8a), 123.95 (C-3), 124.32 (C-1⁰), 129.94 (C-2⁰),

139.59 (C-6), 140.91 (C-2), 149.03 (C-4a), 154.58 (C-7), 161.10

(C-4⁰), 173.33 (C-8).

7.94 (d, 2H, J = 8.9 Hz, H₃), 7.95 (dd, 1H, J = 2.5, 9.1 Hz, H₃), 8.22

(d, 2H, J = 8.9 Hz, H₂), 8.37 (d, 1H, J = 2.5 Hz, H₁), 10.28 (s, 1H,

NH). ¹³C NMR (75 MHz, DMSO-d₆) d ppm: 24.19 (CH₃), 60.06

(OCH_3–7), 112.98 (C-1), 119.22 (C-4), 123.91 (C-8a), 124.81 (q,

J = 272 Hz, CF₃), 125.72 (q, J = 3.8 Hz, C-3⁰), 126.01 (C-3), 129.29

(C-2⁰), 130.49 (q, J = 32.4 Hz, C-4⁰), 134.68 (C-1⁰), 136.73 (C-2),

141.27 (C-6), 150.83 (C-4a), 153.23 (C-7), 173.98 (C-8).

4.1.8.5. 6-Amino-2-(2-ﬂuorophenyl)-3-methoxy-4H-chromen-

4-one (7e). Yellow solid, yield: 82%, mol. wt: 285. Anal. Calcd for

C₁₆H₁₂FNO₃: C, 67.36; H, 4.24; N, 4.91. Found: C, 67.29; H, 4.27;

N, 4.89. ¹H NMR (300 MHz, DMSO-d₆) d ppm: 3.78 (s, 3H, OCH₃),

7.19 (dd, 1H, J = 2.7, 8.8 Hz, H₃), 7.33 (d, 1H, J = 2.7 Hz, H₁), 7.42

4.1.8. General procedure for deprotection of acetamido

derivatives (7a–i)

(m, 1H, H₃), 7.46 (d, 1H, J = 8.8 Hz, H₄), 7.64 (m, 1H, H₄), 7.73

(td, 1H, J = 2.2, 7.6 Hz, H₆). ¹³C NMR (75 MHz, DMSO-d₆) d ppm:

Methoxyﬂavonol 5a–i (10 mmol) was added to a solution of

EtOH (20 mL) and H₂SO₄concd (5 mL). The solution was submitted

to MWI in open vessel 80 °C, 2 + 20 min, upon cooling the solvent

was removed under vacuo and the residue obtain is poured onto

ice water (100 mL). Then the solution was neutralized with NH₄OH

16% until pH 7. The red precipitate formed was collected by ﬁltra-

tion and washed with excess cold water. Amino compound was ob-

tained as a red powder without further puriﬁcation.

53.89 (OCH_3–7), 107.19 (C-1), 116.11–116.39 (d, J = 21.1 Hz, C-3⁰),

118.93–119.36 (d, J = 14.3 Hz, C-1⁰), 119.19 (C-4), 123.43 (C-3),

124.58 (C-5⁰), 124.69 (C-8a), 131.03 (C-6⁰), 132.96–133.08 (d,

J = 7.5 Hz, C-4⁰), 140.68 (C-6), 143.47 (C-2), 148.74 (C-4a), 151.58

(C-7), 160.99–162.48 (d, J = 250.00 Hz, C-2⁰), 173.20 (C-8).

4.1.8.6. 6-Amino-2-(3-ﬂuorophenyl)-3-methoxy-4H-chromen-

4-one (7f). Yellow solid, yield: 89%, mol. wt: 285. Anal. Calcd for

₁₆H₁₂FNO₃: C, 67.36; H, 4.24; N, 4.91. Found: C, 67.32; H, 4.31;

4.1.8.1. 6-Amino-3-methoxy-2-phenyl-4H-chromen-4-one (7a). Yel-

low solid, yield: 80%, mol. wt: 267. Anal. Calcd for C₁₆H₁₃NO₃: C,

71.90; H, 4.90; N, 5.24. Found: C, 71.88; H, 4.92; N, 5.21. ¹H NMR

(300 MHz, DMSO-d₆) d ppm: 3.78 (s, 3H, OCH₃), 7.13 (dd, 1H, J = 8.9,

N, 4.87. ¹H NMR (300 MHz, DMSO-d₆) d ppm: 3.80 (OCH₃), 7.08

(dd, 1H, J = 8.9, 2.7 Hz, H₃), 7.12 (d, 1H, J = 2.7 Hz, H₁), 7.40 (td,

1H, J = 8.5, 2.3 Hz, H₄), 7.48 (d, 1H, J = 8.9 Hz, H₄), 7.61 (td, 1H,

J = 8.0, 6.3 Hz, H₅), 7.81 (dt, 1H, J = 11.1, 1.8 Hz, H₂), 7.87 (br d,

1H, J = 8.0 Hz, H₆). ¹³C NMR (75 MHz, DMSO-d₆) d ppm: 59.81

2.6 Hz, H

H₁), 7.48 (d, 1H, J = 8.9 Hz, H₄), 7.57 (m,

3), 7.21 (d, 1H, J = 2.6 Hz,

1H, H₄), 7.58 (m, 2H, H₃), 8.00 (m, 2H, H₂). ¹³C NMR (75 MHz,

(OCH₃), 104.55 (C-1), 114.82–115.14 (d, J = 24.1 Hz, C-2⁰),

6022

G. Casano et al. / Bioorg. Med. Chem. 18 (2010) 6012–6023

117.42–117.69 (d, J = 20.3 Hz, C-4⁰), 119.16 (C-4), 122.41 (C-3),

124.47–124.49 (d, J = 3.0 Hz, C-6⁰), 124.64 (C-8a), 130.88–130.98

(d, J = 7.5 Hz, C-5⁰), 133.17–133.28 (d, J = 8.3 Hz, C-1⁰), 140.48 (C-

6), 146.45 (C-2), 147.32 (C-4a), 152.69 (C-7) 160.51–163.73 (d,

J = 243 Hz, C-3⁰), 172.83 (C-8).

10% FCS and 1% L-glutamine/penicillin–streptomycin mix with a

range of compound concentrations incorporated in duplicate (ﬁnal

DMSO concentration less than 0.5%). Appropriate controls treated

with or without solvent (DMSO), and various concentrations of

doxorubicin and chloroquine were added to each set of experi-

ments. After 72 h incubation at 37 °C and 6% CO₂, cells were

4.1.8.7. 6-Amino-2-(4-ﬂuorophenyl)-3-methoxy-4H-chromen-

4-one (7g). Yellow solid, yield: 91%, mol. wt: 285. Anal. Calcd for

stained with 5 lL of propidium iodide (1 mg/mL), and their growth

and viability were measured by ﬂow cytometry using a FACSort

ﬂow cytometer (Beckton Dickinson, Paris, France), equipped with

an argon laser (power, 15 mW; wavelength, 488 nm). Settings were:

Forward Scatter (FSC-H), size: Voltage E-1, gain 1, mode Log; Side

Scatter (SSC-H), granulosity: Voltage 250, gain 1, mode Log;

Fluorescence 2 (FL2), red ﬂuorescence: Voltage 551, gain 1, mode Log.

IC₅₀THP1 was deﬁned as the concentration of compound re-

quired to induce a 50% decrease of cell growth as compared to

the control culture. It was calculated by non-linear regression anal-

ysis processed on dose–response curves by the Table Curve soft-

ware 2D v.5.0. IC₅₀values represent the mean value calculated

from three independent experiments.

₁₆H₁₂FNO₃: C, 67.36; H, 4.24; N, 4.91. Found: C, 67.35; H, 4.29;

N, 4.90. ¹H NMR (300 MHz, DMSO-d₆) d ppm: 3.77 (s, 3H, OCH₃),

5.51 (s, 2H, NH₂), 7.06 (dd, 1H, J = 2.8, 8.8 Hz, H₃), 7.12 (d, 1H,

J = 2.8 Hz, H₁), 7.40 (d, 2H, J = 8.9, 5.3 Hz, H₃), 7.44 (d, 1H,

J = 8.8 Hz, H₄), 8.28 (d, 2H, J = 8.9 Hz, H₂). ¹³C NMR (75 MHz,

DMSO-d₆) d ppm: 59.76 (OCH_3–7), 104.59 (C-1), 115.77–116.06

(d, J = 21.9 Hz, C-3⁰), 119.07 (C-4), 122.24 (C-3), 124.68 (C-8a),

127.58–127.60 (d, J = 3.0 Hz, C-1⁰), 130.84–130.96 (d, J = 9.0 Hz,

C-2⁰), 140.00 (C-6), 146.54 (C-2), 147.30 (C-4a), 153.48 (C-7),

161.65–164.96 (d, J = 250.00 Hz, C-4⁰), 173.81 (C-8).

4.1.8.8. 6-Amino-3-methoxy-2-(3-(triﬂuoromethyl)phenyl)-4H-

chromen-4-one (7h). Brown solid, yield: 77%, mol. wt: 335. Anal.

Calcd for C₁₇H₁₂F₃NO₃: C, 60.90; H, 3.61; N, 4.18. Found: C,

60.88; H, 3.65; N, 4.12. ¹H NMR (300 MHz, DMSO-d₆) d ppm:

3.82 (s, 3H, OCH₃), 5.56 (br s, 2H, NH₂), 7.09 (dd, 1H, J = 8.9,

2.6 Hz, H₃), 7.14 (d, 1H, J = 2.6 Hz, H₁).7.51 (d, 1H, J = 8.9 Hz, H₄),

4.2.3. Antiplasmodial activity

In this study, the W2 culture-adapted Plasmodium falciparum

reference strain was used. It is resistant to chloroquine, pyrimeth-

amine and proguanil. Maintenance in continuous culture was done

as described previously by Trager and Jensen.²⁸Parasites were cul-

tivated in 75 cm²-ﬂasks containing RPMI 1640 (20 mL) supple-

mented with 25 mM HEPES, 25 mM NaHCO₃, 10% of A+ human

serum and 1 mL of washed erythrocytes (ﬁnal hematocrit 2.5%).

Parasitaemia was maintained daily between 1% and 6%. Dilutions

used non-infected A+ erythrocytes. Cultures were incubated at

37 °C, 10% O₂, 6% CO₂, 84% N₂, with 90% humidity. Cultures were

monitored daily by microscopic examination of blood smears ﬁxed

with methanol and stained with 10% Giemsa stain. Parasite growth

was assessed by ﬂow cytometry according to a methodology previ-

ously described using hydroethidine (HE, Interchim, Montluçon,

France) that is converted by metabolically active parasites into

ethidium.²⁷After incubation with hydroethidine, parasitized and

uninfected erythrocytes were all identiﬁed on the basis of ﬂuores-

cence intensity and size. Triplicate assays were performed in 96-

well plates (Nunc Brand products, Fisher, Paris, France) containing

7.82 (t, 1H, J = 8.4 Hz, H₅), 7.93 (br d, 1H, J = 8.4 Hz, H₄), 8.30 (br

d, 1H, J = 8.4 Hz, H₆), 8.30 (br s, 1H, H₂). ¹³C NMR (75 MHz,

DMSO-d₆) ppm: 59.72 (OCH₃) 104.28 (C-1), 119.08 (C-4),

124.56 (C-8a), 123.42 (q, J = 270.00 Hz, CF₃), 124.55 (q, J = 3.8 Hz,

C-2⁰), 122.25 (C-3), 126.97 (q, J = 3.8 Hz, C-4⁰), 129.41 (q,

J = 32.4 Hz, C-3⁰), 129.65 (C-5⁰), 132.11 (C-6⁰), 131.97 (C-1⁰),

146.48 (C-2), 152.41 (C-7), 140.37 (C-6), 147.19 (C-4a), 173.68

(C-8).

4.1.8.9. 6-Amino-3-methoxy-2-(4-(triﬂuoromethyl)phenyl)-4H-

chromen-4-one (7i). Yellow solid, yield: 86%, mol. wt: 335. Anal.

Calcd for C₁₇H₁₂F₃NO₃: C, 60.90; H, 3.61; N, 4.18. Found: C,

60.86; H, 3.66; N, 4.14. ¹H NMR (300 MHz, DMSO-d₆) d ppm:

3.80 (s, 3H, OCH₃), 5.54 (s, 2H, NH₂), 7.09 (dd, 1H, J = 2.5, 9.1 Hz,

H₃), 7.12 (d, 1H, J = 2.5 Hz, H₁), 7.47 (d, 1H, J = 9.1 Hz, H₄), 7.92

(d, 2H, J = 8.9 Hz, H₃), 8.21 (d, 2H, J = 8.9 Hz, H₂). ¹³C NMR

(75 MHz, DMSO-d₆) d ppm: 60.01 (OCH_3–7), 104.49 (C-1), 119.17

(C-4), 122.53 (C-3), 124.75 (C-8a), 124.81 (q, J = 272 Hz, CF₃),

125.69 (q, J = 3.8 Hz, C-3⁰), 129.16 (C-2⁰), 130.19 (q, J = 32.4 Hz, C-

4⁰), 135.07 (C-1⁰), 140.81 (C-6), 146.67 (C-2), 147.69 (C-4a),

152.66 (C-7), 173.91 (C-8).

200

L of asynchronous parasite cultures at 2% of parasitaemia and

2% hematocrit, and 5

lL of the appropriate extract dissolved in

DMSO or ultrapure H₂O. Negative control, treated by solvents

(DMSO or H₂O) and positive controls (chloroquine) were added

to each set of experiments. After 48 h incubation without medium

change, plates were centrifuged and the upper liquids were re-

placed with 200 lL hydroethidine solution (0.05 mg/mL in phos-

4.2. Material and methods

phate buffered saline (PBS)). Plates were incubated 20 min in the

dark at 37 °C and washed three times with PBS. Finally, cells were

suspended in 1 mL of PBS to allow determination of the number of

cell events (around 300 per second) and parasitaemia by ﬂow

cytometry using a FACSort ﬂow cytometer. Settings were: Forward

Scatter (FSC-H), size: Voltage E-1, gain 1, mode Log; Side Scatter

(SSC-H), granulosity: Voltage 250, gain 1, mode Log; Fluorescence

2 (FL2), red ﬂuorescence: Voltage 459, gain 1, mode Log. The con-

centrations of compounds required to induce a 50% decrease of in-

fected erythrocytes (IC₅₀W2) was calculated from three

independent experiments.

4.2.1. General

Cell culture medium (RPMI 1640), fetal calf serum (FCS), L-glu-

tamine, non essential amino acids and others medium additives

were from Eurobio (Paris, France). All other chemicals were of

highest chemical purity and were purchased from Sigma except

contrary mention. Stock solutions of quinazoline derivatives were

prepared in DMSO. Stock solutions of reference drugs were pre-

pared in ultrapure H₂O or DMSO. Flow cytometry was performed

at the Faculté de Pharmacie de Marseille, using a FACSort ﬂow

cytometer apparatus (Beckton Dickinson, Paris, France), equipped

with an argon laser (power of 15 mW, and wavelength of 488 nm).

4.2.4. Anti-HIV assays and cytotoxicity on MT-4 cells

The activity of the compounds against HIV-1 (III_Bstrain) and

HIV-2 (ROD) was based on the inhibition of virus-induced cyto-

pathic effect in MT-4 cells using the 3-(4,5-dimethylthiazol-2-yl)-

2,5-diphenyltetrazolium bromide (MTT) method.²⁹Brieﬂy, virus

stocks were titrated in MT-4 cells and expressed as 50% cell culture

infective dose (CC₅₀). MT-4 cells were suspended in culture

4.2.2. Cytotoxic assays on human monocyte THP1

Cytotoxicity of chalcone and ﬂavone derivatives was assessed

on human monocyte THP1 (ATCC, Manassas VA, USA) by ﬂow

cytometry.²⁷Brieﬂy, late log-phase THP1 cells (10⁵cells/mL) were

incubated in RPMI 1640 (without phenol red) supplemented with

G. Casano et al. / Bioorg. Med. Chem. 18 (2010) 6012–6023

6023

medium at 10⁵cells/mL and infected with HIV at a multiplicity of

infection of 0.02. Immediately after virus infection, 100 mL of the

cell suspension was brought into each well of a ﬂat-bottomed

microtiter tray containing various concentrations of the test com-

pounds. The test compounds were dissolved in DMSO at 50 mM

or higher. After a 4-day incubation at 37 °C, the number of viable

cells was determined using the MTT method. Compounds were

tested in parallel for cytotoxic effect in uninfected MT-4 cells.

3. Hayton, K.; Su, X. Z. Curr. Genet. 2008, 54, 223.

4. Daily, J. P. J. Clin. Pharmacol. 2006, 46, 1487.

5. Harborne, J. B.; Williams, C. A. Phytochemistry 2000, 55, 481.

6. Auffret, G.; Labaied, M.; Frappier, F.; Rasoanaivo, P.; Grellier, P.; Lewin, G.

Bioorg. Med. Chem. Lett. 2007, 17, 959.

7. Cordell, G. A.; Angerhofer, C. K.; Pezzuto, J. M. Pure Appl. Chem. 1994, 10,11,

2283.

8. de Monbrison, F.; Maitrejean, M.; Latour, C.; Bugnazet, F.; Peyron, F.; Barron, D.;

Picot, S. Acta Trop. 2006, 97, 102.

9. Portet, B.; Fabre, N.; Roumy, V.; Gornitzka, H.; Bourdy, G.; Chevalley, S.;

Sauvain, M.; Valentin, A.; Moulis, C. Phytochemistry 2007, 68, 1312.

10. Lehane, A. M.; Saliba, K. J. BMC Res. Notes 2008, 1, 26.

11. Sharma, S.; Sharma, S. K.; Modak, R.; Karmodiya, K.; Surolia, N.; Surolia, A.

Antimicrob. Agents Chemother. 2007, 51, 2552.

12. Sharma, S. K.; Parasuraman, P.; Kumar, G.; Surolia, N.; Surolia, A. J. Med. Chem.

2007, 50, 765.

13. Tasdemir, D.; Lack, G.; Brun, R.; Rüedi, P.; Scapozza, L.; Perozzo, R. J. Med. Chem.

2006, 49, 3345.

14. Waller, R. F.; McFadden, G. I. Curr. Issues Mol. Biol. 2005, 7, 57.

15. Dormeyer, M.; Adams, Y.; Kramer, B.; Chakravorty, S.; Tse, M. T.; Pegoraro, S.;

Whittaker, L.; Lanzer, M.; Craig, A. Antimicrob. Agents Chemother. 2006, 50, 724.

16. Reutrakul, V.; Krachangchaeng, C.; Tuchinda, P.; Pohmakotr, M.; Jaipetch, T.;

Yoosook, C.; Kasisit, J.; Sophasan, S.; Sujaritd, K.; Santisuke, T. Tetrahedron

2004, 60, 1517.

4.2.5. Selectivity index (SI)

The selectivity indexes that are presented correspond to the ra-

tios between, respectively, the toxicity on THP1 or MT-4 cell lines

and the W2 antiplasmodial activity or anti-HIV activity. They are

calculated as follows: SI W2 = IC₅₀(THP1)/IC₅₀(W2), SI HIV-

1III_B= CC₅₀(MT-4)/IC₅₀(HIV-1III_B), and SI HIV-2ROD = CC₅₀(MT-

4)/IC₅₀(HIV-2ROD).

Acknowledgment

17. Cos, P.; Maes, L.; Vlietinck, A.; Pieters, L. Planta Med. 2008, 74, 1323.

18. Go, M. L.; Wu, X.; Liu, X. L. Curr. Med. Chem. 2005, 12, 483.

19. Microwaves in Organic Synthesis; Loupy, A., Ed.; New York: Wiley-VCH, 2003.

20. Agrawal, N. N.; Soni, P. A. Indian J. Chem., Sect. B 2005, 44, 2601.

21. Raval, A. A.; Shah, N. M. J. Org. Chem. 1957, 22, 304.

22. Bennett, C. J.; Caldwell, S. T.; McPhail, D. B.; Morrice, P. C.; Duthie, G. G.;

Hartley, R. C. Bioorg. Med. Chem. 2004, 12, 2079.

23. Mentzer, C.; Pillon, D. Compt. Rend. 1952, 234, 444.

24. Li, Z.; Ngojeh, G.; DeWitt, P.; Zheng, Z.; Chen, M.; Lainhart, B.; Li, V.; Felpo, P.

Tetrahedron Lett. 2008, 49, 7243.

G.C. was supported by Région PACA/Syncrosome Ph.D. fellowship.

Supplementary data

Supplementary data associated with this article can be found, in

the online version, at doi:10.1016/j.bmc.2010.06.067. These data

include MOL ﬁles and InChiKeys of the most important compounds

described in this article.

25. Menéndez-Arias, L.; Tözsér, J. Trends Pharmacol. Sci. 2008, 29, 42.

26. Yap, S.; Loft, K. J.; Woodman, O. L.; Williams, S. J. ChemMedChem 2008, 3, 1572.

27. Azas, N.; Laurencin, N.; Delmas, F.; Di Giorgio, C.; Gasquet, M.; Laget, M.;

Timon-David, P. Parasitol. Res. 2002, 88, 165.

References and notes

28. Trager, W.; Jensen, J.-B. Science 1976, 193, 673.

29. Rawal, R. K.; Tripathi, R.; Katti, S. B.; Pannecouque, C.; de Clercq, E. Eur. J. Med.

Chem. 2008, 43, 2800.

1. World Health Organization. World Malaria Report, 2008, 1–215.

2. Karp, C. L.; Auwaerter, P. G. Clin. Infect. Dis. 2007, 45, 1208.

Products guided by the article

Product name:6-amino-3-hydroxy-2-(3-methoxyphenyl)-4H-chromen-4-one

Cas No:1245282-77-2

R&D Labs maybe for 1245282-77-2

Nanjing Capatue Chemical Co., Ltd

Contact:+86-25-86371192 +86-025-85720158

Address:No.20 Jiangjun Avenue, Jiangning Economic & Technical Development Zone
Wuxi Olite Chemical Co., Ltd.

Contact:86-510-82853889

Address:Rm.3732, No.18-2,Yonghe Rd.,Wuxi,Jiangsu,214023,China
Xi'an HO-SHINE Bio-Technology Co., Ltd

Contact:+86 (29) 8248-5435/18292020086

Address:No.6 Shiyuan Road Xian City Shaanxi Province, 710048 China
Hangzhou Think Chemical Co. Ltd

website:http://www.thinkchem.com/

Contact:86-571-89986307/81956191/81956084/81956192

Address:Room 501-502, Tower E, Yuanjian Building, Yuanyang International Center, Hangzhou-310011, China
ShangHai BMG Chemical Co., Ltd

Contact:+86-13524845543

Address:Room 602, no 291 sikai road shanghai

Relevant to this article

Synthesis, reactions, and electronic properties of 16 π-electron octaisobutyltetraphenylporphyrin

Doi:10.1021/ja102817a
(2010)
Rhodium-catalyzed asymmetric 1,4-addition reactions of aryl boronic acids with nitroalkenes: Reaction mechanism and development of homogeneous and heterogeneous catalysts

Doi:10.1039/c7sc03025h
(2017)
Synthesis of 3-amino-2,2-dimethyl-8-thia-1-azaspiro[4.5]decane

Doi:10.1080/00397910903289255
(2010)
Nonadditive effects of structural factors in reactions of aryloxiranes with arenesulfonic acids. Observation of isoparametricity phenomenon

Doi:10.1134/S107042801105006X
(2011)
HAp-encapsulated γ-Fe₂O₃-supported dual acidic heterogeneous catalyst for highly efficient one-pot synthesis of benzoxanthenones and 3-pyranylindoles

Doi:10.1002/aoc.4072
(2018)
Highly enantioselective synthesis of α-(perfluoroalkyl)amines via hydrogenation of enamide precursors in the presence of chiraphos-rhodium catalyst

Doi:10.1016/j.tetasy.2010.05.021
(2010)

Article Doi

Anti-HIV and antiplasmodial activity of original flavonoid derivatives

DOI: 10.1016/j.bmc.2010.06.067

Source and publish data:

Authors:

Article abstract of DOI:10.1016/j.bmc.2010.06.067

Full text of DOI:10.1016/j.bmc.2010.06.067

Products guided by the article

R&D Labs maybe for 1245282-77-2

Relevant to this article

Hot Product