Syntheses of 2-methoxyestradiol and eugenol template based diarylpropenes as non-steroidal anticancer agents

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Syntheses of 2-methoxyestradiol and eugenol

template based diarylpropenes as non-steroidal

anticancer agents

Cite this: RSC Adv., 2014, 4, 35171

Vinay Pathak,^aImran Ahmad,^aAmandeep Kaur Kahlon,^bMohammad Hasanain,^c

Sandeep Sharma,^dKishore K. Srivastava,^dJayanta Sarkar,^cKaruna Shankar,^e

b

a

*

Ashok Sharma and Atul Gupta

Syntheses of 2-methoxyestradiol (1) and eugenol (6) template based conformationally ﬂexible and rigid

diarylpropenes, 14(a–l) and 20(a–e), as nonsteroidal anticancer agents have been performed. The

synthesized compounds were evaluated for their anticancer activity in in vitro using a panel of human

cancer cell lines viz. MCF-7, A549, DU 145, KB and MDA-MB-231by SRB assay. Compounds 14i, 14k and

15a showed signiﬁcant anticancer activity at IC₅₀between 10.27 mM to 27.91 mM in diﬀerent cancer cell

lines. The most active molecule, 14k, inhibited proliferation of cells by inducing apoptosis and arresting

the cell cycle at the G2/M phase. In vitro toxicity of these compounds (14i, 14k and 15a) in healthy

hepatic monocyte (THP-1) cells showed high selectivity of compounds towards cancerous vs. healthy cells.

Received 26th April 2014

Accepted 30th July 2014

DOI: 10.1039/c4ra03823a

www.rsc.org/advances

2ME2 (2) are reported to have diverse biological activities

including anticancer activity.^16,17

Introduction

Furthermore, eugenol (6), another structurally similar

natural product, present in ocimum sanctum L (sweet basil) and

clove (syzygium aromaticum L) displays diverse biological activ-

ities such as antimicrobial, antioxidant, and anticancer activi-

ties etc. (Fig. 1).^18,19In two independent studies, the weak

anticancer activity of 6 was potentiated by use of gemcitabine (7)

and 2ME2 respectively in combination therapy.^20,21These

observations concluded that eugenol (6) has synergetic eﬀect on

cell proliferation inhibition. In literature, a substituted diary-

lpropene derivative isolated from Dalbergia paviora (legumi-

nosae) has been reported for signicant cell proliferation

inhibitory activity.²²Following this lead, Ito et al. synthesized

diﬀerent non-target specic diarylpropene analogues as cancer

2-Methoxyestradiol (2ME2, 2), a metabolite of 17b-estradiol (1),

possess potent antiproliferative, antiangiogenic and proa-

poptotic activities and is now an investigational drug for cancer

chemotherapy under the trade name Panzem® (Fig. 1).^1–8In

humans, 2ME2 is formed via transformation of estradiol (1) to

2-hydroxyestradiol (2OHE2) which is nally converted into

2ME2 with the help of hepatic cytochrome P450 and catechol-O-

transferase enzymes.^9,10The antiproliferative activity of 2ME2 is

independent of estrogen receptors (ERs) since it has very weak

interactions with ERs, rather it acts through its binding with the

colchicine binding site of b-tubulin protein.^11–15

Structurally, the presence of a phenyl ring bearing a hydroxy

and methoxy group in the tetracyclic steroidal framework is a

prime requirement for biological activity of 2ME2. Similarly,

some natural products such as combretastatin CA4 (3), iso-

eugenol (4) and dehydrozingerone (5) which also possess a

phenyl ring bearing a hydroxy and methoxy group similar to

^aMedicinal Chemistry Department, CSIR-Central Institute of Medicinal and Aromatic

Plants, P.O. CIMAP, Kukrail Road, Lucknow-226015, India. E-mail: atisky2001@

yahoo.co.in; Tel: +91 5222718556

^bBiotechnology Division, CSIR-Central Institute of Medicinal and Aromatic Plants, P.O.

CIMAP, Kukrail Road, Lucknow-226015, India

^cDivision of Biochemistry, CSIR-Central Drug Research Institute, Sec-10, Jankipuram

Extension, Lucknow, India

^dDivision of Microbiology, CSIR-Central Drug Research Institute, Sec-10, Jankipuram

Extension, Lucknow, India. Tel: +91 5222718556

^eAnalytical Chemistry Department, CSIR-Central Institute of Medicinal and Aromatic

Plants, P.O. CIMAP, Kukrail Road, Lucknow-226015, India

Fig. 1 Estradiol derivatives, cytotoxic phytomolecules and designed

Prototype I and II.

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conversion of 2ME2 into 2-methoxyestrone (2ME1), there is a

need to develop non-steroidal mimics of 2ME2 which can have

similar mode of action and devoid of many side eﬀects associ-

ated with 2ME2.^24,25

Realizing the biological potential of diarylpropene pharma-

cophore and its suitability with the objective of present study,

diﬀerent target oriented (i.e. estrogen receptor(ER) and/or

tubulin protein), 2-methoxyestradiol (2ME2) and eugenol (6)

template based conformationally exible and rigid diary-

lpropenes of type I and II have been synthesized as non-

steroidal cancer chemotherapeutic agents and evaluated for

their cytotoxic activity in diﬀerent cancer cell lines (specially in

ER + cell line) for cancer chemotherapy (Fig. 1).

The proposed prototypes will have a phenyl ring bearing a

hydroxy and methoxy group similar to 2ME2 (2), CA4 (3) and

eugenol (6), and a cytostatic portion which could possibly

encompass the region homologous to the rings C and D

complex of 2ME2.

Scheme 1 Reagent and conditions (a) KOH in ethanol, 35–40 ^ꢀC; (b)

10% Pd/C, ethylacetate–methanol (1 : 1), 35–40 ^ꢀC; (c) sodium

borohydride, dry ethanol, 35–40 ^ꢀC; (d) HCl, methanol, reﬂux. ^aIn case

of hydroxy derivatives of 10, R ¼ THP which was deprotected during

workup and gave hydroxy derivative of 11.

Results and discussion

Chemistry

The synthesis of prototype-I was started through base catalyzed

Aldol condensation of substituted acetophenone (9) and benz-

aldehyde (10) at room temperature which gave diaryl prope-

nones (11) in 82–92% yields (Scheme 1). NMR spectroscopic

analyses of diarylpropenone derivatives (11) revealed trans

stereochemistry across the C]C bond. Diarylpropenones (11)

were subjected to catalytic hydrogenation using 10% palladium

adsorbed on charcoal (Pd/C) in ethylacetate–methanol mixture

(8 : 2) at normal pressure and temperature for about 3 h which

yielded diarylpropanones (12) in 66–93% yields. Subsequently,

reduction of 12 using sodium borohydride at room temperature

yielded diarylpropanols (13) as racemic mixture in quantitative

yields. The racemic mixture of compound 13 on dehydration in

presence of HCl in ethanol at reux for 1 h gave desired diary-

lpropenes (14) in 48–85% yields.

Proton NMR spectroscopic analyses of diarylpropene deriv-

atives (14) showed coupling constant (J value) in the range of

15.6 to 15.9 Hertz for olenic proton which revealed trans

stereochemistry across the C]C bond. For SAR study,

compound 15 was proposed to be synthesized from compound

14k. Synthesis of 15 was done through catalytic hydrogenation

of 14k using 10% palladium adsorbed on charcoal (Pd/C) in

ethylacetate–methanol mixture (8 : 2) at normal pressure and

temperature for about 1 h, yielded 15 in 78–90% yield.

The synthesis of target compounds of prototype (II) was

made using same methodology used for synthesis of prototype-I

(Scheme 2). Cyclic ketones (16) such as 6-methoxytetralone, 5-

methoxyindanone, 4,5-dimethoxyindanone and substituted

benzaldehyde (10) were used as starting materials to generate

chalcones (17) which on reduction of C]C double bond using

catalytic hydrogenation gave compound 18 as racemic mixture.

Compound 18 on sodium borohydride reduction yielded 19 as

diasteromeric mixture. Compound 19 on dehydration under

acidic reaction conditions yielded compound 20. Generally,

Scheme 2 Reagent and conditions (a) (i) KOH in ethanol, 35–40 ^ꢀC (ii)

HCl; (b) 10% Pd/C, ethylacetate–methaol (1 : 1), 35–40 ^ꢀC; (c) sodium

borohydride, dry ethanol, 35–40 ^ꢀC; (d) HCl, methanol, reﬂux. ^aIn case

of hydroxy derivatives of 10, R ¼ THP which was deprotected during

workup and gave hydroxy derivative of 17.

chemo-preventive agents and evaluated them in a single cancer

cell line using curcumin as positive control.²³

In view of the fact that main clinical demerit of 2ME2 is

limited bioavailability due to its transformation into glucur-

onoids and 17b-hydroxydehydrogenase (17b-HSD) mediated

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Table 1 In vitro anticancer activity of compounds 14 (a–l), 15 (a–c) and 20 (a–e) using SRB assay (IC₅₀in mM)^b,cand in vitro cytotoxicity in THP-1

Cells using resazurin assay (CC₅₀in mM)

CC₅₀(mM)

IC₅₀(mM) (mean ꢂ SE)

S no

Compound

MCF-7

A549

DU145

KB

MDA-MB-231

THP-1

1

2

3

4

14a

14b

14c

14d

14e

66.32 ꢂ 8.55

78.72 ꢂ 6.54

54.59 ꢂ 2.03

54.57 ꢂ 1.03

>50

37.00 ꢂ 3.72

55.90 ꢂ 6.64

48.35 ꢂ 4.99

50.69 ꢂ 5.77

>50

44.60 ꢂ 3.59

72.22 ꢂ 2.70

60.01 ꢂ 2.98

58.34 ꢂ 3.59

>50

20.10 ꢂ 4.47

58.11 ꢂ 7.31

42.58 ꢂ 4.58

41.05 ꢂ 4.47

>50

60.84 ꢂ 4.58

—

>100

66.44 ꢂ 1.66

65.79 ꢂ 0.17

5

—

6

7

8

9

14f

>100

—

65.23 ꢂ 1.16

56.96 ꢂ 1.43

>100

—

150

—

300

—

300

100

—

14g

14h

14i

14j

14k

14l

20a

20b

20c

20d

20e

15a

15b

15c

Eugenol

TAM

2ME2

68.74^a

52.40^a

>100

53.83 ꢂ 11.30

38.01 ꢂ 27.49

19.12 ꢂ 10.47

38.752^a

45.28 ꢂ 26.78

16.03 ꢂ 1.54

34.44 ꢂ 2.13

14.27 ꢂ 1.11

56.45 ꢂ 1.77

48.08 ꢂ 0.85

>100

23.06^a

31.49^a

16.45 ꢂ 0.45

32.67 ꢂ 1.48

10.27 ꢂ 0.86

47.66 ꢂ 5.52

46.85 ꢂ 6.95

>100

26.53 ꢂ 7.19

10

11

12

13

14

15

16

17

18

19

20

21

22

23

>50

17.99 ꢂ 12.96

64.29 ꢂ 2.33

59.81 ꢂ 1.91

>100

—

39.14 ꢂ 4.48

31.94 ꢂ 2.83

46.23^a

71.80 ꢂ 4.95

66.39 ꢂ 6.77

81.97 ꢂ 4.23

51.53 ꢂ 6.05

53.84 ꢂ 19.11

56.66 ꢂ 18.69

14.97 ꢂ 9.61

>100^a

58.82^a

>100

79.70^a

67.16^a

>100

13.42 ꢂ 4.03

11.73 ꢂ 1.34

21.56 ꢂ 5.25

—

>100^a

—

57.80 ꢂ 9.96

40.69^a

14.45^a

33.69^a

<6.25^a

33.50 ꢂ 1.14

10.37 ꢂ 0.84

7.51^a

33.19 ꢂ 2.74

12.14 ꢂ 0.62

—

38.58^a

—

8.74 ꢂ 1.17

11.40 ꢂ 2.02

8.41 ꢂ 1.15

—

>30^a

<1.73^a

>30^a

a

Although the compounds had been tested thrice in this cell line, value of one assay was >50 (a) or >100 (b), therefore it could not be included in

calculation of mean and SE. ^bValues are represented as mean IC₅₀value ꢂ SE of three independent experiments, (ꢁ) ¼ not done. ^cCell lines used:

A549 (lung carcinoma), DU 145 (prostate carcinoma), KB (oral carcinoma contaminated with HeLa cells), MCF-7 (ER+ breast adenocarcinoma) and

MDA-MB-231 (ERꢁ breast adenocarcinoma).

yields at each step of the synthesis were good and comparable to breast adenocarcinoma) using SRB assay. Further, Docking

the corresponding open chain analogues (Scheme 1).

experiments were performed for the most active compound 14k

The synthesized compounds were characterized by the use of using b-tubulin protein and estrogen receptor a to predict the

diﬀerent spectroscopic techniques viz. NMR, IR, mass possible mode of action.

spectrometry.

In vitro anticancer activity

HPLC analysis

The anticancer activity of compounds, 14 (a–l), 15 (a–c) and 20 (a–

The purity of compounds 14 (a–l), 15 (a–c) and 20 (a–e) was e) is described by half maximal inhibitory concentration (IC₅₀)

determined using high-low chromatographic approach on value in Table 1. Most of the compounds have shown anticancer

reverse phase solid matrix C₁₈coupled with photo diode array activity at IC₅₀value between 10.27 mM to 81.97 mM in diﬀerent

(PDA) detector with gradient mobile phase composition of cancer cell lines under study. In these experiments, tamoxifen

acetonitrile–water (80 : 20, v/v) with and without acid additives at (TAM), 2-methoxyestradiol (2ME2) and eugenol (6) were used as

a ow rate of 1.0 mL min^ꢁ1. Peak area normalization method of positive control (Table 1). Out of twenty compounds, compounds

high-low chromatographic analysis was adopted to determine the 14i, 14k and 15a showed signicant anticancer activity at IC₅₀

chromatographic purity and the concentration of every identied between 10.27 mM to 27.91 mM in diﬀerent cancer cell lines

HPLC peak of compounds in the absence of primary standards. comparable to tamoxifen (TAM), 2-methoxyestradiol (2ME2) and

The purity of the compounds ranged 98–99%.

eugenol (6) (Table 1). Compound 14k was found to be most active

compound among two series.

Biology

In vitro toxicity in healthy hepatomonocyte (THP-1) cells

The compounds 14 (a–l), 15(a–c) and 20 (a–e) were investigated

for their anticancer activity in in vitro model in a panel of human Compound 14i, 14k and 15 (a–c) were further evaluated for their

cancer cell lines viz. A549 (lung carcinoma), DU 145 (prostate inherent toxicity in healthy hepatic monocyte (THP-1) cells in

carcinoma), KB (oral carcinoma contaminated with HeLa cells), vitro to know their selectivity towards cancerous cell vs. healthy

MCF-7 (ER+ breast adenocarcinoma) and MDA-MB-231 (ERꢁ cells. The toxicity results showed that compounds 14k, 15a and

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Fig. 2 Eﬀect of 14k on cell division cycle (a, b) MCF-7 cells were treated with 14k at IC₅₀concentrations for 24 h. After staining with PI, cells were

subjected to ﬂow cytometry. (c) Histogram showing average population cells in various phases (G1, G2, S) of cell cycle (mean ꢂ S.E. of three

independent assays, each performed in duplicate). #P < 0.05, *P < 0.001 compared with vehicle treated controls.

Fig. 3 14k induced apoptosis in MCF-7 cells, MCF-7 cells were treated with the compound at IC₅₀concentrations for 24 h at 37 ^ꢀC. Cells were

stained with DAPI and images acquired on a ﬂuorescent microscope (Nikon, Japan) using 20ꢃ objective.

15b did not show any toxicity to the healthy cells at 300 mM

concentration whereas, compound 14i and 15c was devoid of

any toxicity to the healthy THP-1 cells at 150 mM and 100 mM

concentrations respectively. The toxicity assessment results and

anticancer activities of (IC₅₀value) of these compounds (14i,

14k and 15a) showed many fold selectivity towards cancerous

cell vs. healthy cells.

Cell division cycle study

Being a potent molecule of the both series, compound 14k was

further studied for detailed biological characterization. For this

purpose, estrogen receptor (ER) positive human breast cancer

cell line (MCF-7) was selected for subsequent biological assays.

The eﬀect of 14k on cell division cycle was studied. Aer 24 h

incubation with the compound at 15 mM concentration (near

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IC₅₀value), 14k showed signicant accumulation of G2/M colchicines (8) and ring B of the combretastin-A4 (CA4, 3) and

population compared to the vehicle treated controls (Fig. 2a– the remaining nonplanar part is homologous to the rings C and

c). This was associated with signicant decrease in cells at S and D complex.²⁶Similarly, it is possible that structural arrange-

G0/G1 phase.

ment of compound 14k allows it to interact with b-tubulin for its

We further investigated ability of 14k to trigger apoptosis in cytotoxic activity in general and has ER mediated selectivity for

MCF-7 cells. Cells were exposed to the compound at IC₅₀cytotoxic activity in ER positive cells (MCF-7 cells) in particular.

concentration for 24 h, stained with DAPI and were observed This was further supported by docking experiment (discussed

under uorescent microscope for fragmented nuclei, a hall- below). Removal of double bond from 14k (compound 15a) did

mark of apoptosis. Compound 14k caused marked fragmenta- not aﬀect anticancer activity of 14k, however, in case of 14i,

tion of MCF-7 cellular nuclei in comparison to the vehicle removal of C]C double bond (compound 15b) abolished the

control group (Fig. 3).

biological activity. The anticancer activity of 14k and 15a in ER

positive cancer cells (MCF-7 cells) can be assumed due to better

structural complementarities of these derivatives with ligand

binding pocket of ER.

Structure–activity relationship (SAR) study

Further, the structure–activity (SAR) relationship of synthesized

compounds revealed that position of double bond in these

molecules had great impact on their biological activity.

Docking study

Compound 14h and 14k are positional isomers with respect to To verify our assumptions, docking experiments were per-

the position of double bond (C]C). Both compounds bear a formed (Table 2) for compound 14k on b-tubulin and estrogen

methoxyphenyl group and a trimethoxyphenyl group linked receptor-a (Fig. 4b and 5b). Docking of 14k at colchicine

together by –HC]CH–CH₂linker. Compound 14k showed binding site showed good binding within colchicine binding

better activity (at IC₅₀10.27 mM to 17.99 mM) than 14h (at IC₅₀site of b-tubulin with binding energy of ꢁ5.34 kcal mol^ꢁ1and

23.06 mM to 45.28 mM) in all cancer cell lines. The observed inhibitory constant (K_ivalue) of 121.87 mM. It had a hydrogen

diﬀerence in their activity might be due to position of the bond (H-bond) interactions via oxygen atom of trimethox-

ꢀ

double bond. Based on their observation, Amato et al. have yphenyl group with bond distance of 3.06 A with Cys b241amino

shown that ring A of 2ME2 is homologous to the ring C of acid of b-tubulin similar to colchicine (5) and 2ME2 (2).^27,28

Table 2 Docking interactions of 2ME2, 14k on b-tubulin and 14k, 14k⁰and 17-b-estradiol, on estrogen receptor-a (ERa)

Binding

energy

(kcal

K_ivalue

(inhibitory

constant)

Number of rotatable

bonds

Name/Pubchem ID

Structure

mol^ꢁ1

)

Hydrogen bond

(A) b-tubulin receptor

2-methoxyestradiol (2ME-2)

(CID_66414)

Cys241: HG, Lys352: HZ3,

Asn349: O

ꢁ6.42

ꢁ5.34

19.67 mM

3

7

14k

121.87 mM

Cys241: HG

(B) Estrogen receptor

His524: HD1, Arg394: HH21,

Glu353: OE1

17-b-Estradiol

ꢁ9.83

62.57 nM

3

14k

ꢁ5.9

47.33 mM

138.5 mM

Leu327: HN

7

14k⁰

ꢁ5.26

Glu353: OE2, Ile326:HN

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Fig. 4 (a and b) Docking poses of 2-methoxyestradiol (2ME2, 2) & 14k within colchicine binding site of b-tubulin.

Fig. 5 (a) Docking pose of compound 17b-estradiol (1) of within LBD of Estrogen Receptor-a, (b) Docking pose of compound 14K within LBD

Estrogen Receptor-a, (c) Docking pose of compound 14K⁰within LBD of within LBD of Estrogen Receptor-a.

Further, docking of 14k on ER-a [PDB:1A52] showed one H- I and II, established signicant anticancer activity. Compounds

bond interaction between trimethoxyphenyl group of 14k with 14i, 14k and 15a showed potential cytotoxicites against various

Leu327 of ligand binding pocket (LBP) having bond distance of human cancer cell lines and were found to be non-toxic against

ꢀ

2.85 A in a region encompassed by rings C and D (Fig. 5a). The healthy hepatic monocyte (THP-1) cells. Anti-cancer activity of

binding energy and inhibitory constant for 14k were found to be the most potent molecule (14k) was found to be mediated

ꢁ5.9 kcal mol^ꢁ1and 47.33 mM respectively (Fig. 5b). Interest- through induction of apoptosis by arresting cells at G2/M phase

ingly, a virtual hydroxyl derivative of 14k (14k⁰) showed one H- of division cycle. In the both series, conformationally exible

bond interaction between trimethoxyphenyl group and Ile326 diarylpropenes were more active than structurally rigid

in a region encompassed by rings C and D of 17b-estradiol (1) analogues possibly due to molecular exibility. Further struc-

ꢀ

with bond distance of 3.27 A (Fig. 5c). Additionally, there is one tural modications of these diarylpropenes may lead to a good

more H-bond interaction between hydroxyl group of ring A of lead in future for development of ER selective anticancer drug

0

ꢀ

14k and Glu353 with bond distance of 2.87 A. The binding molecules.

energy and inhibition constant for 14k⁰were found to be ꢁ5.26

kcal mol^ꢁ1and 138.5 mM respectively.

Experimental section

General

Conclusion

The reagents and the solvents used in this study were of

In conclusions, 2-methoxyestradiol (1) and eugenol (6) template analytical grade and used without further purication. All the

based conformationally exible and rigid diarylpropenes of type reactions were monitored on Merck aluminium thin layer

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chromatography (TLC, UV_{254 nm}) plates. Column chromatog- 147.27, 148.77, 153.54 (3

ꢃ

C), 189.88 (C]O); ESIMS

raphy was carried out on silica gel (60–120 mesh). The melting (C₁₉H₂₀O₆): m/z ¼ 345 [M + H]⁺, 367 [M + Na]⁺.

points were determined on Buchi melting point M560 appa-

3-(4-Hydroxy-3-methoxyphenyl)-1-(3,4-dimethoxyphenyl)-

ratus in open capillaries and are uncorrected. Commercial prop-2-en-1-one (11b). Yield: (2.84 g), 82%; m.p. 128–129 ^ꢀC; R_f:

reagents were used without purication.¹H and ¹³C NMR 0.20 (30% ethyl acetate–hexane); IR (KBr, n_maxcm^ꢁ1): 3333,

spectra were recorded on a Bruker WM-300 (300 MHz) using 1644, 1588, 1559, 1510, 1024, 801, 722; ¹H NMR (CDCl₃, 300

CDCl₃and DMSO-d₆as the solvent. Chemical shi are reported MHz, d ppm): 3.92–3.95 (m, 9H, 3 ꢃ OCH₃), 6.04 (bs, 1H, OH),

in parts per million shi (d-value) based on the middle peak of 6.90–6.96 (m, 2H, ArH), 7.11 (s, 1H, ArH), 7.20–7.29 (m, 1H,

the solvent (CDCl₃–DMSO-d₆) (d 75.00 ppm for ¹³C NMR) as the ArH), 7.36–7.41 (d, J ¼ 15.3 Hz, 1H, CH), 7.57–7.65 (m, 2H, ArH),

internal standard. Signal patterns are indicated as s, singlet; bs, 7.69 (d, J ¼ 11.7 Hz, 1H, CH); ¹³C NMR (CDCl₃, 75 MHz, d ppm):

broad singlet; d, doublet; dd, double doublet; t, triplet; m, 56.42 (OCH₃), 56.47 (2 ꢃ OCH₃), 110.38, 110.67, 111.31, 115.32,

multiplet; brm, broad multiplet. Coupling constants (J) are 119.79, 123.27, 123.43, 128.06, 131.98, 144.78, 147.25, 148.59,

given in Hertz. Infrared (IR) spectra were recorded on a Perkin- 149.65, 153.55, 189.60 (C]O); ESIMS (C₁₈H₁₈O₅): m/z ¼ 315

Elmer AX-1 spectrophotometer in KBr disc and reported in wave [M + H]⁺, 337 [M + Na]⁺, 353 [M + K]⁺.

number (cm^ꢁ1). ESI mass spectra were recorded on Shimadzu

LC-MS and LC-MS-MS APC3000 (Applied Biosystems) aer dis- en-1-one (11c). Yield: (3.10 g), 82%; m.p. 157–158 C; R_f: 0.30

3-(4-Hydroxy-3-methoxyphenyl)-1-(4-methoxyphe_ꢀnyl)prop-2-

solving the compounds in acetonitrile and methanol.

(30% ethyl acetate–hexane); IR (KBr, n_maxcm^ꢁ1): 3317, 1651,

1

1591, 1426, 1278, 1220, 1172, 1025, 981, 820; H NMR (CDCl₃,

300 MHz, d ppm): 3.87 (s, 3H, OCH₃), 3.94 (s, 3H, OCH₃), 6.03 (s,

1H, OH), 6.91–6.98 (m, 3H, ArH), 7.12 (s, 1H, ArH), 7.19–7.25 (m,

1H, ArH), 7.38 (d, J ¼ 15.3 Hz, 1H, CH), 7.68 (d, J ¼ 14.4 Hz, 1H,

General procedure for the synthesis of compounds (11a–m)

(E)-3-(3,4,5-Trimethoxyphenyl)-1-(4-methoxyphenyl)prop-2- CH), 8.02 (d, J ¼ 8.7 Hz, 2H, ArH); ¹³C NMR (CDCl₃, 75 MHz, d

en-1-one (11k). In a round bottomed ask compound 9 (R₁¼ R₃ppm): 55.90 (OCH₃), 56.42(OCH₃), 110.46, 114.20 (2 ꢃ C),

¼ H, R₂¼ OCH₃, 2.00 g, 13.00 mmol) was dissolved into 115.28, 119.93, 123.57, 128.05, 131.14 (2 ꢃ C), 131.72, 144.79,

methanol (20 mL) and methanolic KOH (10%, 20 mL) was 147.21, 148.54, 163.69, 189.27(C]O); ESIMS (C₁₇H₁₆O₄): m/z ¼

added to this solution drop wise on ice bath. Aer 20 minutes, 285 [M + H]⁺, 307 [M + Na]⁺.

compound 10 (R⁰]R⁰⁰]OCH₃, R]CH₃, 2.62 g, 13.00 mmol)

1-(Benzo[d][1,3]dioxol-6-yl)-3-(4-hydroxy-3-methoxyphenyl)-

dissolved in methanol (15 mL) was added to reaction mixture. prop-2-en-1-one (11d). Yield: (3.34 g), 92%; m.p. 153–154 ^ꢀC; R_f:

The reaction mixture was allowed to stir at ice bath for 30 0.50 (10% ethyl acetate–hexane); IR (KBr, n_maxcm^ꢁ1): 3265,

minutes and aerwards at room temperature for 12 h. The 1641, 1596, 1563, 1501, 1450, 1258, 1034, 843, 801; ¹H NMR

progress of reaction was monitored using TLC. Aer completion (CDCl₃, 300 MHz, d ppm): 3.95 (s, 3H, OCH₃), 6.05 (s, 3H, OH

of reaction, solvent was evaporated followed by drop wise and OCH₂), 6.88 (d, J ¼ 8.1 Hz, 1H, ArH), 6.94 (d, J ¼ 8.1 Hz, 1H,

addition of dilute HCl was made and pH of the content was ArH), 7.11 (s, 1H, ArH), 7.19 (d, J ¼ 8.1 Hz, 1H, ArH), 7.32 (d, J ¼

adjusted to acidic. The content was extracted with ethyl acetate. 15.6 Hz, 1H, CH), 7.51 (s, 1H, ArH), 7.63 (d, J ¼ 8.1 Hz, 1H, ArH),

The organic layer was then separated and dried over anhydrous 7.73 (d, J ¼ 15.6 Hz, 1H, CH); ¹³C NMR (CDCl₃, 75 MHz, d ppm):

sodium sulphate (Na₂SO₄) and concentrated. The crude mate- 56.43 (OCH₃), 102.23 (CH₂), 108.28, 108.84, 110.44, 115.29,

rial was puried by crystallization by methanol which yielded 119.76, 123.66, 124.90, 127.97, 133.62, 145.04, 147.24, 148.63 (2

pure compound 11k as yellow solid. Yield: (3.58 g), 82%; m.p. ꢃ C), 151.63, 188.77 (C]O); ESIMS (C₁₇H₁₄O₅): m/z ¼ 299 [M +

134–135 C; R_f: 0.34 (30% ethyl acetate–hexane); IR (KBr, n_maxH]⁺, 321 [M + Na]⁺.

ꢀ

1

cm^ꢁ1): 3448, 1656, 1601, 1504, 1460, 1220, 1118, 1029, 998; H

1-(Benzo[d][1,3]dioxol-5-yl)-3-(4-methoxyphenyl)prop-2-en-1-

ꢀ

NMR (CDCl₃, 300 MHz, d ppm): 3.83–3.91 (m, 12H, 4 ꢃ OCH₃), one (11e). Yield: (2.68 g), 78%; m.p. 147–148 C; R_f: 0.44 (20%

6.85 (s, 2H, ArH), 6.97 (d, J ¼ 9.0 Hz, 2H, ArH), 7.40 (d, J ¼ 15.6 ethyl acetate–hexane); IR (KBr, n_maxcm^ꢁ1): 2905, 2840, 1648,

Hz, 1H, CH), 7.70 (d, J ¼ 15.3 Hz, 1H, CH), 8.02 (d, J ¼ 8.7 Hz, 1580, 1502, 1441, 1249, 1031, 929, 805; ¹H NMR (CDCl₃, 300

2H, ArH); ¹³C NMR (CDCl₃, 75 MHz, d ppm): 55.89 (OCH₃), 56.63 MHz, d ppm): 3.83 (s, 3H, OCH₃), 6.03 (s, 2H, CH₂), 6.85–6.92

(2 ꢃ OCH₃), 61.39 (OCH₃), 106.02 (2 ꢃ C), 114.24 (2 ꢃ C), (m, 3H, ArH), 7.75 (d, J ¼ 15.6 Hz, 1H, CH), 7.50–7.63 (m, 4H,

121.66, 130.99, 131.20 (2 ꢃ C), 131.54, 140.71, 144.53, 153.88, ArH), 7.35 (d, J ¼ 15.6 Hz, 1H, CH); ¹³C NMR (CDCl₃, 75 MHz, d

163.81 (2 ꢃ C), 189.09 (C]O); ESIMS (C₁₉H₂₀O₅): m/z ¼ 329 ppm): 55.79 (OCH₃), 102.20 (CH₂), 108.27, 108.83, 114.81 (2 ꢃ

[M + H]⁺.

C), 119.85, 124.85, 128.16, 130.51 (2 ꢃ C), 133.68, 144.47,

3-(4-Hydroxy-3-methoxyphenyl)-1-(3,4,5-trimethoxyphenyl)- 148.64, 151.91, 162.00, 188.69 (C]O); ESIMS (C₁₇H₁₄O₄): m/z ¼

prop-2-en-1-one (11a). Yield: (2.52 g), 77%; m.p. Oil ^ꢀC; R_f: 0.22 305 [M + Na]⁺.

(30% ethyl acetate–hexane); IR (KBr, n_maxcm^ꢁ1): 3369, 2933,

1,3-Bis(4-methoxyphenyl)prop-2-en-1-one (11f). Yield: (2.89

1651, 1576, 1509, 1340, 1156, 1124, 1028, 793; ¹H NMR (CDCl₃, g), 81%; m.p. 98–99 C; R_f: 0.40 (30% ethyl acetate–hexane); IR

300 MHz, d ppm): 3.93–3.95 (m, 12H, 4 ꢃ OCH₃), 6.95 (d, J ¼ 8.1 (KBr, n_maxcm^ꢁ1): 2954, 2841, 1655, 1594, 1506, 1330, 1253, 1216,

Hz, 1H, ArH), 7.11 (d, J ¼ 1.5 Hz, 1H, ArH), 7.22–7.42 (m, 4H, 1168, 1018, 817; ¹H NMR (CDCl₃, 300 MHz, d ppm): 3.84 (s, 3H,

ArH), 7.75 (d, J ¼ 15.6 Hz, 1H, CH); ¹³C NMR (CDCl₃, 75 MHz, d OCH₃), 3.88 (s, 3H, OCH₃), 6.91–6.98 (m, 4H, ArH), 7.41 (d, J ¼

ppm): 56.45 (OCH₃), 56.87 (2 ꢃ OCH₃), 61.35 (OCH₃), 106.66 (2 15.3 Hz, 1H, CH), 7.59 (d, J ¼ 8.7 Hz, 2H, ArH), 7.77 (d, J ¼ 15.6

ꢃ C), 110.93, 115.37, 119.99, 123.39, 127.89, 134.23, 145.57, Hz, 1H, CH), 8.02 (d, J ¼ 9.0 Hz, 2H, ArH); ¹³C NMR (CDCl₃, 75

ꢀ

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MHz, d ppm): 55.79 (OCH₃), 55.86 (OCH₃), 114.19 (2 ꢃ C),

114.80 (2 ꢃ C), 120.04, 128.26, 130.48 (2 ꢃ C), 131.09 (2 ꢃ C),

131.80, 144.20, 161.93, 163.68, 189.19 (C]O); ESIMS

(C₁₇H₁₆O₃): m/z ¼ 269 [M + H]⁺.

3-(3,4,5-Trimethoxyphenyl)-1-(4-hydroxy-3-methoxyphenyl)-

prop-2-en-1-one (11m). Yield: (2.65 g), 64%; m.p. 183–186 ^ꢀC; R_f:

1

0.20 (30% ethyl acetate–hexane); H NMR (CDCl₃, 300 MHz, d

ppm): 3.89–3.96 (m, 12H, 4 ꢃ OCH₃), 6.24 (s, 1H, OH), 6.85 (s,

2H, ArH), 6.98 (d, J ¼ 7.5 Hz, 1H, ArH), 7.41 (d, J ¼ 15.6 Hz, 1H,

CH), 7.62–7.65 (m, 2H, ArH), 7.71 (d, J ¼ 15.6 Hz, 1H, CH);

(CDCl₃, 75 MHz, d ppm): 56.34 (OCH₃), 56.66 (2 ꢃ OCH₃), 61.37

OCH₃, 106.13 (2 ꢃ C), 110.96, 114.17, 121.43, 124.04, 130.98,

131.47, 140.82, 144.52, 147.38, 150.83, 153.90 (2 ꢃ C), 188.90

(C]O); ESIMS (C₁₉H₂₀O₆): m/z ¼ 345 [M + H]⁺, 367 [M + Na]⁺.

1-(3,4-Dimethoxyphenyl)-3-(4-methoxyphenyl)prop-2-en-1-

one (11g). Yield: (2.98 g), 90%; m.p. 86–87 ^ꢀC; R_f: 0.15 (20% ethyl

acetate–hexane); IR (KBr, n_maxcm^ꢁ1): 3057, 3005, 1650, 1571,

1507, 1248, 1158, 1026, 823, 796, 766; ¹H NMR (CDCl₃, 300 MHz,

d ppm): 3.85–3.96 (m, 9H, 3 ꢃ OCH₃), 6.91–6.95 (m, 3H, ArH),

7.43 (d, J ¼ 15.6 Hz, 1H, CH), 7.58–7.69 (m, 4H, ArH), 7.75–7.81

(d, J ¼ 15.6 Hz, 1H, CH); ¹³C MR (CDCl₃, 75 MHz, d ppm): 55.80

(OCH₃), 56.45 (2 ꢃ OCH₃), 110.40, 111.26, 114.80 (2 ꢃ C),

119.80, 123.22, 128.23, 130.51 (2 ꢃ C), 132.02, 144.22, 149.63,

153.51, 161.94, 189.05 (C]O); ESIMS (C₁₈H₁₈O₄): m/z ¼ 299

[M + H]⁺, 321 [M ꢁ H]⁺.

General procedure for the synthesis of compounds (12a–m)

3-(3,4,5-Trimethoxyphenyl)-1-(4-methoxyphenyl)propan-1-one

(12k). Compound 11k (1.00 g, 3.04 mmol) was taken in a round

1-(3,4,5-Trimethoxyphenyl)-3-(4-methoxyphenyl)prop-2-en-1- bottomed ask and dissolved in ethyl acetate–methanol

ꢀ

one (11h). Yield: (2.81 g), 90%; m.p. 99–100 C; R_f: 0.24 (20% mixture (8 : 2). The mixture was ushed with nitrogen gas and

ethyl acetate–hexane); IR (KBr, n_maxcm^ꢁ1): 2939, 2838, 1655, palladium charcoal (Pd/C, 5% wt) (0.10 g) was added and

1573, 1457, 1028, 993, 821, 707; ¹H NMR (acetone-D₆, 300 MHz, hydrogen gas was passed to it for 3 h. The progress of reaction

d ppm): 3.77 (s, 3H, OCH₃), 3.78 (s, 3H, OCH₃), 3.81 (s, 6H, 2 ꢃ was monitored by TLC. Aer completion of the reaction, the

OCH₃), 6.99 (d, J ¼ 9.0 Hz, 2H, ArH), 7.43 (s, 2H, ArH), 7.74– solvent was evaporated and crude material was worked up using

7.77(m, 4H, ArH and CH); ¹³C NMR (CDCl₃, 75 MHz, d ppm): ethyl acetate and water. The organic layer was the separated,

55.31 (OCH₃), 56.18 (2 ꢃ OCH₃), 60.22 (OCH₃), 106.58 (2 ꢃ C), dried anhydrous sodium sulphate (Na₂SO₄) and concentrated.

114.74 (2 ꢃ C), 119.84, 128.21, 130.82 (2 ꢃ C), 134.19, 142.98, The crude was puried by column chromatography on silica gel

144.04, 153.83 (2

ꢃ

C), 162.19, 188.19 (C]O); ESIMS (100–200 mesh size) using ethyl acetate–hexane (12 : 88) as

(C₁₉H₂₀O₅): m/z ¼ 329 [M + H]⁺.

eluents which yielded pure compound 12k as white solid. Yield:

3-(3,4,5-Trimethoxyphenyl)-1-(3,4-dimethoxyphenyl)prop-2- (0.88 g), 88%; m.p. 94–95 ^ꢀC; R_f: 0.52 (30% ethyl acetate–

en-1-one (11i). Yield: (3.58 g), 90%; m.p. 126–127 ^ꢀC; R_f: 0.20 hexane); IR (KBr, n_maxcm^ꢁ1): 2938, 2837, 1683, 1251, 1178, 1124,

(30% ethyl acetate–hexane); IR (KBr, n_maxcm^ꢁ1): 2998, 2947, 1012, 845; ¹H NMR (CDCl₃, 300 MHz, d ppm): 2.99 (t, J ¼ 7.5 Hz,

2833, 1657, 1583, 1511, 1465, 1416, 1268, 1124, 1023, 818, 766; 2H, CH₂), 3.23 (t, J ¼ 7.5 Hz, 2H, CH₂), 3.81–3.85 (m, 12H, 4 ꢃ

¹H NMR (CDCl₃, 300 MHz, d ppm): 3.81–3.85 (m, 15H, 5 ꢃ OCH₃), 6.45 (s, 2H, ArH), 6.92 (d, J ¼ 8.7 Hz, 2H, ArH), 7.93 (d, J

OCH₃), 6.87–6.94 (m, 3H, ArH), 7.43 (d, J ¼ 15.6 Hz, 1H, CH), ¼ 8.7 Hz, 2H, ArH); ¹³C NMR (CDCl₃, 75 MHz, d ppm): 31.21

7.62–7.74 (m, 3H, CH and ArH); ¹³C NMR (CDCl₃, 75 MHz, d (CH₂), 40.59 (CH₂), 55.85 (OCH₃), 56.50 (2 ꢃ OCH₃), 61.22

ppm): 56.48 (2 ꢃ OCH₃), 56.64 (2 ꢃ OCH₃), 61.39 (OCH₃), (OCH₃), 105.87, 114.14 (2 ꢃ C), 130.42, 130.69 (2 ꢃ C), 137.66 (2

106.04 (2 ꢃ C), 110.34, 111.25, 121.46, 123.41, 130.97, 131.77, ꢃ C), 153.61 (3 ꢃ C), 163.90, 198.21 (C]O); ESIMS (C₁₉H₂₂O₅):

140.72, 144.54, 149.70, 153.67, 153.87 (2 ꢃ C), 188.97 (C]O); m/z ¼ 353 [M + H]⁺, 369 [M + K]⁺.

ESIMS (C₂₀H₂₂O₆): m/z ¼ 381[M + Na]⁺, 397[M + K]⁺.

3-(4-Hydroxy-3-methoxyphenyl)-1-(3,4,5-trimethoxyphenyl)-

3-(4-Hydroxyphenyl)-1-(3,4,5-trimethoxyphenyl)prop-2-en-1- propan-1-one (12a). Yield: (0.93 g), 92%; m.p. 122–123 ^ꢀC; R_f:

one (11j). Yield: (2.69 g), 90%; m.p. 155–156 C; R_f: 0.20 (30% 0.54 (20% ethyl acetate–hexane); IR (KBr, n_maxcm^ꢁ1): 3411,

ꢀ

ethyl acetate–hexane); IR (KBr, n_maxcm^ꢁ1): 3404, 2937, 1586, 2934, 2840, 1667, 1265, 1236, 1127, 1029, 998, 851; ¹H NMR

1509, 1236, 1125, 1002, 830; ¹H NMR (CDCl₃, 300 MHz, d ppm): (CDCl₃, 300 MHz, d ppm): 2.98 (t, J ¼ 7.3 Hz, 2H, CH₂), 3.22 (t, J

3.85–3.95 (m, 9H, 3 ꢃ OCH₃), 6.89 (d, J ¼ 8.7 Hz, 2H, ArH), 7.27 ¼ 7.3 Hz, 2H, CH₂), 3.86–3.90 (m, 12H, 4 ꢃ OCH₃), 5.55 (s, 1H,

(s, 2H, ArH), 7.36 (d, J ¼ 15.3 Hz, 1H, CH), 7.51–7.56 (m, 2H, OH), 6.73, (bs, 2H, ArH), 6.70 (d, J ¼ 7.8 Hz, 1H, ArH), 7.22 (s,

ArH), 7.75 (d, J ¼ 15.6 Hz, 1H, CH); ¹³C MR (CDCl₃, 75 MHz, d 2H, ArH); ¹³C NMR (CDCl₃, 75 MHz, d ppm): 30.56 (CH₂), 41.11

ppm): 55.75 (2 ꢃ OCH₃), 60.22 (OCH₃), 105.36, 115.60 (2 ꢃ C), (CH₂), 56.30 (OCH₃), 56.71 (2 ꢃ OCH₃), 61.33 (OCH₃), 106.00 (2

117.76, 125.50, 129.89 (2 ꢃ C), 133.34, 144.54, 152.45 (2 ꢃ C), ꢃ C), 111.65, 114.82, 121.28, 132.61, 133.61, 143.02, 144.42,

159.70, 188.54 (C]O); ESIMS (C₁₈H₁₈O₅): m/z ¼ 313 [M ꢁ H]⁺, 146.88, 153.47 (2 ꢃ C), 198.65 (C]O); ESIMS (C₁₉H₂₂O₆): m/z ¼

315 [M + H]⁺.

345 [M ꢁ H]⁺, 369 [M + Na]⁺.

3-(4-Hydroxyphenyl)-1-(4-methoxyphenyl)prop-2-en-1-one

3-(4-Hydroxy-3-methoxyphenyl)-1-(3,4-dimethoxyphenyl)-

(11l). Yield: (2.68 g), 79%; m.p. 179–180 ^ꢀC; R_f: 0.30 (30% ethyl propan-1-one (12b). Yield: (0.83 g), 82%; m.p. 141–142 C; R_f:

ꢀ

acetate–hexane); ¹H NMR (DMSO-d₆, 300 MHz, d ppm): 3.38 (s, 0.25 (30% ethyl acetate–hexane); IR (KBr, n_maxcm^ꢁ1): 3355,

1

3H, OCH₃), 6.82 (d, J ¼ 8.4 Hz, 2H, ArH), 7.05 (d, J ¼ 8.4 Hz, 2H, 1648, 1019, 792; H NMR (CDCl₃, 300 MHz, d ppm): 2.88–2.93

ArH), 7.60–7.74 (m, 4H, CH and ArH), 8.11 (d, J ¼ 8.7 Hz, 2H, (m, 2H, CH₂), 3.12–3.17 (m, 2H, CH₂), 3.79 (s, 3H, OCH₃), 3.84

ArH); ¹³C NMR (DMSO-d₆, 75 MHz, d ppm): 55.56 (OCH₃), (bs, 6H, 2 ꢃ OCH₃), 5.46 (s, 1H, OH), 6.65–6.67 (m, 2H, ArH),

113.98 (2 ꢃ C), 115.84 (2 ꢃ C), 118.45, 125.96, 130.75 (2 ꢃ C), 6.75–6.81 (m, 2H, ArH), 7.45–7.51 (m, 2H, ArH); ¹³C NMR

130.82, 130.92 (2 ꢃ C), 143.68, 160.00, 163.03, 187.30 (C]O); (CDCl₃, 75 MHz, d ppm): 32.18 (CH₂), 36.76 (CH₂), 49.71 (OCH₃),

ESIMS (C₁₆H₁₄O₃): m/z ¼ 255 [M + H]⁺, 277 [M + Na]⁺.

55.63 (OCH₃), 56.49 (OCH₃), 104.83, 107.83, 114.28 (2 ꢃ C),

35178 | RSC Adv., 2014, 4, 35171–35185

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129.72, 130.26 (2 ꢃ C), 132.11, 149.41, 149.88, 155.99, 158.51,

207.04 (C]O); ESIMS (C₁₈H₂₀O₅): m/z ¼ 339 [M + Na]⁺, 354

[M + K]⁺.

1-(3,4-Dimethoxyphenyl)-3-(4-methoxyphenyl)propan-1-one

ꢀ

(12g). Yield: (0.81 g), 80%; m.p. 64–65 C; R_f: 0.31 (30% ethyl

acetate–hexane); IR (KBr, n_maxcm^ꢁ1): 3447, 3004, 2931, 1668,

1

3-(4-Hydroxy-3-methoxyphenyl)-1-(4-methoxyphenyl)propan-

1-one (12c). Yield: (0.86 g), 85%; m.p. 112–113 ^ꢀC; R_f: 0.50 (30%

ethyl acetate–hexane); IR (KBr, n_maxcm^ꢁ1): 3504, 1671, 978, 822,

780; ¹H NMR (CDCl₃, 300 MHz, d ppm): 2.91 (bs, 2H, CH₂), 3.24

(t, J ¼ 7.6 Hz, 2H, CH₂), 3.81 (s, 3H, OCH₃), 3.87 (s, 3H, OCH₃),

6.72 (bs, 2H, ArH), 6.89 (s, 1H, ArH), 7.00 (d, J ¼ 9.0 Hz, 2H,

ArH), 7.33 (s, 1H, OH), 7.98 (d, J ¼ 9.0 Hz, 2H, ArH); ¹³C NMR

(CDCl₃, 75 MHz, d ppm): 30.20 (CH₂), 40.36 (CH₂), 55.40 (OCH₃),

55.74 (OCH₃), 112.52, 114.06 (2 ꢃ C), 115.17, 121.11, 130.54 (2

ꢃ C), 130.63, 133.38, 145.20, 147.72, 163.86, 197.63(C]O);

ESIMS (C₁₇H₁₈O₄): m/z ¼ 287 [M + H]⁺, 309 [M + Na]⁺.

1263, 1156, 1026, 889, 822, 767; H NMR (CDCl₃, 300 MHz, d

ppm): 2.99 (t, J ¼ 7.6 Hz, 2H, CH₂), 3.21 (t, J ¼ 7.6 Hz, 2H, CH₂),

3.77 (s, 3H, OCH₃), 3.91–3.93 (m, 6H, 2 ꢃ OCH₃), 6.82–6.87 (m,

3H, ArH), 7.16 (d, J ¼ 8.1 Hz, 2H, ArH), 7.52–7.58 (m, 2H, ArH);

¹³C NMR (CDCl₃, 75 MHz, d ppm): 30.02 (CH₂), 40.65 (CH₂),

55.66 (OCH₃), 56.38 (OCH₃), 56.43(OCH₃), 110.44, 110.63,

114.34 (2 ꢃ C), 123.04, 129.75 (2 ꢃ C), 130.60, 133.80, 149.45,

153.65, 158.39, 198.45 (C]O); ESIMS (C₁₈H₂₀O₄): m/z ¼ 323 [M

+ Na]⁺, 339 [M + K]⁺.

3-(3,4,5-Trimethoxyphenyl)-1-(3,4-dimethoxyphenyl)propan-1-

one (12i). Yield: (0.93 g), 93%; m.p. 95–96 ^ꢀC; R_f: 0.28 (30% ethyl

acetate–hexane); IR (KBr, n_maxcm^ꢁ1): 2941, 2839, 1678, 1009, 872,

1-(Benzo[d][1,3]dioxol-6-yl)-3-(4-hydroxy-3-methoxyphenyl)-

propan-1-one (12d). Yield: (0.66 g), 66%; m.p. 80–81 ^ꢀC; R_f: 0.31

(30% ethyl acetate–hexane); IR (KBr, n_maxcm^ꢁ1): 3495, 2930,

1677, 1251, 1033, 982, 928, 866, 823; ¹H NMR (CDCl₃, 1d DMSO-

d₆, 300 MHz, d ppm): 2.94–2.99 (m, 2H, CH₂), 3.15–3.20 (m, 2H,

CH₂), 3.86 (s, 3H, OCH₃), 5.54 (s, 1H, OH), 6.02 (s, 2H, OCH₂O),

6.65–6.77 (m, 2H, ArH), 6.81–6.86 (m, 2H, ArH), 7.42 (s, 1H,

ArH), 7.54 (d, J ¼ 8.4 Hz, 1H, ArH); ¹³C NMR (CDCl₃, 1d DMSO-

d₆, 75 MHz, d ppm): 30.54 (CH₂), 40.94 (CH₂), 56.30 (OCH₃),

102.22 (CH₂), 108.26, 111.59, 114.78, 121.26, 124.65, 132.24,

133.64, 144.36, 146.85, 148.59 (2 ꢃ C), 152.11, 197.91 (C]O);

ESIMS (C₁₇H₁₆O₅): m/z ¼ 299 [M ꢁ H]⁺, 323 [M + Na]⁺.

1-(Benzo[d][1,3]dioxol-5-yl)-3-(4-methoxyphenyl)propan-1-

one (12e). Yield: (0.92 g), 92%; m.p. 51–52 ^ꢀC; R_f: 0.64 (30% ethyl

acetate–hexane); IR (KBr, n_maxcm^ꢁ1): 2911, 1666, 1242, 1034,

814, 785; ¹H NMR (acetone-D₆, 300 MHz, d ppm): 2.91 (t, J ¼ 7.5

Hz, 2H, CH₂), 3.22 (t, J ¼ 7.5 Hz, 2H, CH₂), 3.73 (s, 3H, OCH₃),

6.08 (s, 2H, CH₂), 6.82 (d, J ¼ 8.4 Hz, 2H, ArH), 6.91 (d, J ¼ 8.1

Hz, 1H, ArH), 7.18 (d, J ¼ 8.4 Hz, 2H, ArH), 7.42 (d, J ¼ 1.5 Hz,

1H, ArH), 7.63 (d, J ¼ 8.1 Hz, 1H, ArH); ¹³C NMR (acetone-D₆, 75

MHz, d ppm): 29.59 (CH₂), 40.26 (CH₂), 54.94 (OCH₃), 102.45

(CH₂), 107.72, 108.11, 114.09 (2 ꢃ C), 124.57, 129.72 (2 ꢃ C),

130.40, 133.88, 148.64, 152.05, 158.52, 197.10; ESIMS

(C₁₇H₁₆O₄): m/z ¼ 307 [M + Na]⁺.

1

776; H NMR (acetone-D₆, 300 MHz, d ppm): 2.90–2.95 (m, 2H,

OCH₂), 3.26–3.31 (m, 2H, CH₂), 3.67 (s, 3H, OCH₃), 3.78 (s, 6H, 2

ꢃ OCH₃), 3.85–3.87 (m, 6H, 2 ꢃ OCH₃), 6.59 (s, 2H, ArH), 7.01 (d,

J ¼ 8.4 Hz, 1H, ArH), 7.52 (d, J ¼ 2.1 Hz, 1H, ArH), 7.66 (dd, J ¼ 2.1

and 2.1 Hz, 1H, ArH); ¹³C NMR (CDCl₃, 75 MHz, d ppm): 31.00

(CH₂), 39.99 (CH₂), 55.00 (OCH₃), 55.87(2 ꢃ OCH₃), 55.69 (OCH₃),

59.96 (OCH₃), 106.30 (2 ꢃ C), 110.89, 111.00, 122.90, 130.61,

137.02, 137.77, 149.65, 153.78 (2 ꢃ C), 154.00, 197.64 (C]O);

ESIMS (C₂₀H₂₄O₆): m/z ¼ 283 [M + Na]⁺, 399 [M + K]⁺.

3-(4-Hydroxyphenyl)-1-(3,4,5-trimethoxyphenyl)propan-1-

ꢀ

one (12j). Yield: (0.68 g), 68%; m.p. 141–142 C; R_f: 0.29 (30%

ethyl acetate–hexane); IR (KBr, n_maxcm^ꢁ1): 3439, 2990, 1664,

1230, 1124, 999, 826, 775; ¹H NMR (acetone-D₆, 300 MHz, d

ppm): 2.89 (t, J ¼ 7.2 Hz, 2H, CH₂), 3.24–3.29 (m, 2H, CH₂), 3.78

(s, 3H, OCH₃), 3.87 (s, 6H, 2 ꢃ OCH₃), 6.73 (d, J ¼ 9.0 Hz, 2H,

ArH), 7.09 (d, J ¼ 7.8 Hz, 2H, ArH), 7.29 (s, 2H, ArH), 8.15 (bs,

1H, OH); ¹³C NMR (acetone-D₆, 75 MHz, d ppm): 29.97 (CH₂),

40.70 (CH₂), 56.30 (2 ꢃ OCH₃), 60.38 (OCH₃), 106.29 (2 ꢃ C),

115.74 (2 ꢃ C), 129.98 (2 ꢃ C), 132.86, 133.14, 153.95(3 ꢃ C),

156.26, 198.30 (C]O); ESIMS (C₁₈H₂₀O₅): m/z ¼ 315 [M + H]⁺,

339 [M + 2H + Na]⁺.

3-(4-Hydroxyphenyl)-1-(4-methoxyphenyl)propan-1-one (12l).

Yield: (0.85 g), 85%; m.p. 82–83 ^ꢀC; R_f: 0.40 (30% ethyl acetate–

hexane); ¹H NMR (CDCl₃, 300 MHz, d ppm): 2.97 (t, J ¼ 7. 5 Hz,

2H, CH₂), 3.21 (t, J ¼ 7.6 Hz, 2H, CH₂), 3.85 (s, 3H, OCH₃), 6.06

(bs, 1H, OH), 6.78 (d, J ¼ 8.4 Hz, 2H, ArH), 6.92 (d, J ¼ 9.0 Hz,

2H, ArH), 7.08 (d, J ¼ 8.1 Hz, 2H, ArH), 7.94 (d, J ¼ 8.7 Hz, 2H,

ArH); ¹³C NMR (CDCl₃, 75 MHz, d ppm): 29.56 (CH₂), 40.37

(CH₂), 55.44 (OCH₃), 113.73 (2 ꢃ C), 115.36 (2 ꢃ C), 129.44 (2 ꢃ

C), 129.76, 130.42 (2 ꢃ C), 133.04, 154.14, 163.51, 198.86 (C]O);

ESIMS (C₁₆H₁₆O₃): m/z ¼ 257 [M + H]⁺, 279 [M + Na]⁺.

1,3-Bis(4-methoxyphenyl)propan-1-one (12f). Yield: (0.86 g),

86%; R_f: 0.42 (20% ethyl acetate–hexane); IR (KBr, n_maxcm^ꢁ1):

2934, 1680, 1032, 823, 742, 691; ¹H NMR (acetone-D₆, 300 MHz,

d ppm): 2.98 (t, J ¼ 7.5 Hz, 2H, CH₂), 3.34 (t, J ¼ 7.5 Hz, 2H, CH₂),

3.77 (s, 6H, 2 ꢃ OCH₃), 6.86 (d, J ¼ 8.7 Hz, 2H, ArH), 7.23 (d, J ¼

8.4 Hz, 2H, ArH), 7.53 (d, J ¼ 8.1 Hz, 2H, ArH), 8.03 (d, J ¼ 7.5

Hz, 2H, ArH); ESIMS (C₁₇H₁₈O₃): m/z ¼ 261 [M + H]⁺, 283

[M + Na]⁺.

1-(3,4,5-Trimethoxyphenyl)-3-(4-methoxyphenyl)propan-1-

one (12h). Yield: (0.80 g), 80%; m.p. 91–92 ^ꢀC; R_f: 0.53 (30%

ethyl acetate–hexane); IR (KBr, n_maxcm^ꢁ1): 3003, 2935, 1675,

3-(3,4,5-Trimethoxyphenyl)-1-(4-hydroxy-3-methoxyphenyl)-

propan-1-one (12m). Yield: (0.80 g) 80%; R_f: 0.0.37 (30% ethyl

acetate–hexane); ¹H NMR (CDCl₃, 300 MHz, d ppm): 2.99 (t, J ¼

7.5 Hz, 2H, CH₂), 3.21 (t, J ¼ 7.5 Hz, 2H, CH₂), 3.79–3.83 (m,

12H, 4 ꢃ OCH₃), 6.46 (s, 2H, ArH), 6.97 (d, J ¼ 8.1 Hz, 1H, ArH),

7.60–7.63 (m, 2H, ArH); ¹³C NMR (CDCl₃, 75 MHz, d ppm): 31.20

(CH₂), 40.63 (CH₂), 55.85 (OCH₃), 56.23 (2 ꢃ OCH₃), 61.22

(OCH₃), 105.87, 114.14 (2 ꢃ C), 130.42, 130.69, 137.66 (2 ꢃ C),

153.61 (3 ꢃ C), 156.8, 163.90, 198.21 (C]O); ESIMS (C₁₉H₂₂O₆):

m/z ¼ 346 [M + H]⁺.

1

1246, 1122, 1008, 816, 763; H NMR (CDCl₃, 300 MHz, d ppm):

2.99 (t, J ¼ 7.3 Hz, 2H, CH₂), 3.22 (t, J ¼ 7.5 Hz, 2H, CH₂), 3.77 (s,

3H, OCH₃), 3.89 (bs, 9H, 3 ꢃ OCH₃), 6.84 (d, J ¼ 8.4 Hz, 2H,

ArH), 7.15–7.19 (m, 4H, ArH); ¹³C NMR (CDCl₃, 75 MHz, d ppm):

29.93 (CH₂), 40.97 (CH₂), 55.66 (OCH₃), 56.71 (2 ꢃ OCH₃), 61.31

(OCH₃), 106.02 (2 ꢃ C), 114.39 (2 ꢃ C), 129.78 (2 ꢃ C), 132.62,

133.73, 143.03, 153.48 (2 ꢃ C), 158.47, 198.53 (C]O); ESIMS

(C₁₉H₂₂O₅): m/z ¼ 353 [M + Na]⁺, 369 [M + K]⁺.

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814, 766; ¹H NMR (CDCl₃, 300 MHz, d ppm): 3.46 (d, J ¼ 6.3 Hz,

2H, CH₂), 3.87 (bs, 9H, 3 ꢃ OCH₃), 5.52 (bs, 1H, OH), 6.17–6.24

(m, 1H, CH), 6.37 (d, J ¼ 15.9 Hz, 1H, CH), 6.73–6.91 (m, 6H,

ArH); ¹³C NMR (CDCl₃, 75 MHz, d ppm): 39.43 (CH₂), 56.22

(OCH₃), 56.34 (2 ꢃ OCH₃), 109.03, 111.57, 111.64, 114.71,

119.53, 121.71, 128.16, 130.78, 131.07, 132.61, 144.42, 146.91,

148.86, 149.44; ESIMS (C₁₈H₂₀O₄): m/z ¼ 323 [M + Na]⁺.

General procedure for the synthesis of compounds (13a–m)

1-(4-Methoxyphenyl)-3-(3,4,5-trimethoxyphenyl)propan-1-ol

(13k). In a round bottomed ask, compound 12k (0.86 g, 2.60

mmol) was dissolved in methanol and kept at 0 ^ꢀC for 15–20

minutes. To this mixture sodium borohydride (NaBH_4,0.29 g,

7.80 mmol), was added and reaction was transferred to room

temperature aer half an hour. The progress of reaction was

monitored by TLC (30% ethyl acetate–hexane). Aer completion

of reaction, solvent was taken oﬀ and the reaction mixture was

treated with NH₄Cl and worked up using ethyl acetate and

water. The organic layer was the separated, dried anhydrous

sodium sulphate (Na₂SO₄) and concentrated. The crude solid

material was puried by washing it with hexane which yielded

pure compound 13k as white solid in 98% (3.58 g), yield which

was further processed for hydrolysis as such. The experimental

procedure used for synthesis of compound 13a–m is same as

described for compound 13k. The molar ratio of reactants was

same for synthesis of all derivatives.

4-(4-Methoxycinnamyl)-2-methoxyphenol (14c). Yield: (0.42

ꢀ

g), 50%; m.p. 92–93 C; R_f: 0.57 (30% ethyl acetate–hexane); IR

(KBr, n_maxcm^ꢁ1): 3435, 1606, 1512, 1459, 1435, 1265, 1237, 1028,

834, 786; ¹H NMR (CDCl₃, 300 MHz, d ppm): 3.41 (d, J ¼ 6.6 Hz,

2H, CH₂), 3.76 (s, 3H, OCH₃), 3.80 (s, 3H, OCH₃), 6.18–6.28 (m,

1H, CH), 6.40 (d, J ¼ 15.6 Hz, 1H, CH), 6.66–6.86 (m, 5H, ArH),

7.32 (d, J ¼ 8.7 Hz, 2H, ArH), 7.38 (s, 1H, OH); ¹³C NMR (CDCl₃,

75 MHz, d ppm): 39.01 (CH₂), 55.02 (OCH₃), 55.75 (OCH₃),

112.52, 114.26 (3 ꢃ C), 115.27, 121.29, 127.54 (2 ꢃ C), 127.94,

130.21, 130.80, 145.33, 147.82, 159.44; ESIMS (C₁₇H₁₈O₃): m/z ¼

293 [M + Na]⁺, 309 [M + K]⁺.

4-(3-(Benzo[d][1,3]dioxol-6-yl)allyl)-2-methoxyphenol (14d).

ꢀ

Yield: (0.66 g), 85%; m.p. 78–79 C; R_f: 0.6 (10% ethyl acetate–

General procedure for the synthesis of compounds (14a–m)

hexane); IR (KBr, n_maxcm^ꢁ1): 3455, 1607, 1500, 1444, 1253, 1035,

5-(4-Methoxycinnamyl)-1,2,3-trimethoxybenzene (14k). In a 880, 794; ¹H NMR (CDCl₃, 300 MHz, d ppm): 3.45 (d, J ¼ 6.3 Hz,

round bottomed ask, compound 13k (0.83 g, 2.50 mmol) was 2H, CH₂), 3.87 (s, 3H, OCH₃), 5.53 (s, 1H, OH), 5.93 (bs, 2H, CH₂),

dissolved in ethanol and conc. HCl (1 mL) was added to it. The 6.11–6.21 (m, 1H, ArH), 6.32–6.37 (d, J ¼ 15.6 Hz, 1H, ArH), 6.72–

reaction mixture was transferred for reux. The progress of 6.80 (m, 4H, CH and ArH), 6.85–6.91(m, 2H, ArH); ¹³C NMR

reaction was monitored by TLC (30% ethyl acetate–hexane). (CDCl₃, 75 MHz, d ppm): 39.32 (CH₂), 56.31 (OCH₃), 101.37 (CH₂),

Aer completion of reaction, solvent was taken oﬀ and the 105.95, 108.64, 111.57, 114.71, 120.95, 121.65, 128.30, 130.73,

reaction mixture was worked up using ethyl acetate and water. 132.45, 132.54, 144.40, 146.90, 147.20, 148.37; ESIMS (C₁₇H₁₆O₄):

The organic layer was the separated, dried over anhydrous m/z ¼ 285 [M + H]⁺, 307 [M + Na]⁺, 323 [M + K]⁺.

sodium sulphate (Na₂SO₄) and concentrated. The crude solid

5-(3-(4-Methoxyphenyl)prop-1-enyl)benzo[d][1,3]dioxole (14e).

material was puried by column chromatography on silica gel Yield: (0.42 g), 54%; m.p. oil; R_f: 0.80 (30% ethyl acetate–

(100–200 mesh size) using hexane as eluents which yielded pure hexane); IR (KBr, n_maxcm^ꢁ1): 2924, 1609, 1508, 1443, 1246, 1038,

compound 14k as white solid. Yield: (0.44 g), 54%; m.p. 61–62 934, 816; ¹H NMR (CDCl₃, 300 MHz, d ppm): 3.46 (d, J ¼ 6.6 Hz,

^ꢀC; R_f: 0.45 (30% ethyl acetate–hexane); IR (KBr, n_maxcm^ꢁ1): 2H, CH₂), 3.79 (s, 3H, OCH₃), 6.49 (s, 2H, CH₂), 6.11–6.21 (m,

1

2936, 2835, 1593, 1507, 1459, 1330, 1239, 1120, 1017, 832; H 1H, CH), 6.34 (d, J ¼ 15.6 Hz, 1H, CH), 6.69–6.90 (m, 5H, ArH),

NMR (CDCl₃, 300 MHz, d ppm): 3.46 (d, J ¼ 6.6 Hz, 2H, CH₂), 7.14 (d, J ¼ 8.4 Hz, 2H, ArH); ¹³C NMR (CDCl₃, 75 MHz, d ppm):

3.80–3.84 (m, 12H, 4 ꢃ OCH₃), 6.16–6.24 (m, 1H, CH), 6.39–6.45 38.72 (CH₂), 55.69 (OCH₃), 101.34 (CH₂), 105.97, 108.61, 114.34

(m, 3H, CH and ArH), 6.84 (d, J ¼ 8.7 Hz, 2H, ArH), 7.30 (d, J ¼ (2 ꢃ C), 120.90, 128.39, 129.95 (2 ꢃ C), 130.71, 132.52, 132.72,

8.7 Hz, 2H, ArH); ¹³C NMR (CDCl₃, 75 MHz, d ppm): 40.09 (CH₂), 147.17, 148.36, 158.49; ESIMS (C₁₇H₁₆O₃): m/z ¼ 307 [M + K]⁺.

55.69 (OCH₃), 56.51 (2 ꢃ OCH₃), 61.25 (OCH₃), 106.00 (2 ꢃ C),

1,3-Bis(4-methoxyphenyl)prop-1-ene (14f). Yield: (0.37 g),

114.38 (2 ꢃ C), 127.19, 127.67 (2 ꢃ C), 130.65, 130.95, 136.00, 48%; m.p. 63–64 ^ꢀC; R_f: 0.85 (30% ethyl acetate–hexane); IR

153.65 (3 ꢃ C), 159.35; ESIMS (C₁₉H₂₂O₄): m/z ¼ 337 [M + Na]⁺, (KBr, n_maxcm^ꢁ1): 2953, 2902, 1609, 1510, 1243, 1032, 823; H

1

353 [M + K]⁺.

NMR (acetone-D₆, 300 MHz, d ppm): 3.44 (d, J ¼ 6.6 Hz, 2H,

4-(3,4,5-Trimethoxycinnamyl)-2-methoxyphenol (14a). Yield: CH₂), 3.76(bs, 6H, 2 ꢃ OCH₃), 6.18–6.28 (m, 1H, CH), 6.40 (d, J

(0.38 g), 48%; m.p. Oil; R_f: 0.37 (30% ethyl acetate–hexane); IR ¼ 15.9 Hz, 1H, CH), 6.85 (d, J ¼ 8.4 Hz, 4H, ArH), 7.15 (d, J ¼ 8.1

(KBr, n_maxcm^ꢁ1): 3424, 2937, 2837, 1582, 1509, 1458, 1236, 1124, Hz, 2H, ArH), 7.32 (d, J ¼ 8.7 Hz, 2H, ArH); ¹³C NMR (acetone-

787; ¹H NMR (CDCl₃, 300 MHz, d ppm): 3.46 (d, J ¼ 6.0 Hz, 2H, D₆, 75 MHz, d ppm): 38.48 (CH₂), 54.97 (OCH₃), 55.02 (OCH₃),

CH₂), 3.80–3.89 (m, 12H, 4 ꢃ OCH₃), 5.52 (s, 1H, OH), 6.21–6.28 114.17 (2 ꢃ C), 114.20 (2 ꢃ C), 127.54 (2 ꢃ C), 127.81, 129.82 (2

(m, 1H, CH), 6.35 (d, J ¼ 15.9 Hz, 1H, CH), 6.58 (s, 2H, ArH), ꢃ C), 130.36, 130.76, 132.82, 158.66, 159.48; ESIMS (C₁₇H₁₈O₂):

6.72–6.75 (m, 2H, ArH), 6.86 (d, J ¼ 8.4 Hz, 1H, ArH); ¹³C NMR m/z ¼ 253 [M ꢁ H]⁺, 255[M + H]⁺, 277 [M + Na]⁺.

(CDCl₃, 75 MHz, d ppm): 39.35 (CH₂), 56.33 (OCH₃), 56.49 (2 ꢃ

1,2-Dimethoxy-4-(3-(4-methoxyphenyl)prop-1-enyl)benzene

OCH₃), 61.30 (OCH₃), 103.70 (2 ꢃ C), 111.70, 114.76, 121.76, (14g). Yield: (0.47 g), 60%; m.p. 48–49 ^ꢀC; R_f: 0.61 (30% ethyl

129.60, 131.03, 132.31, 133.66, 137.99, 144.51, 146.95, 153.72 (2 acetate–hexane); IR (KBr, n_maxcm^ꢁ1): 2930, 2839, 1605, 1509,

ꢃ C); ESIMS (C₁₉H₂₄O₆): m/z ¼ 331 [M + H]⁺, 329 [M ꢁ H]⁺.

1268, 1240, 1126, 1019, 966, 818; H NMR (CDCl₃, 300 MHz, d

1

4-(3,4-Dimethoxycinnamyl)-2-methoxyphenol (14b). Yield: ppm): 3.48 (d, J ¼ 6.3 Hz, 2H, CH₂), 3.80–3.88 (m, 9H, 3 ꢃ OCH₃),

(0.59 g), 63%; m.p. 103–134 ^ꢀC; R_f: 0.4 (20% ethyl acetate– 6.15–6.25 (m, 1H, CH), 6.37 (d, J ¼ 15.9 Hz, 1H, CH), 6.78–6.91

hexane); IR (KBr, n_maxcm^ꢁ1): 3488, 1513, 1462, 1264, 1139, 1025, (m, 5H, ArH), 7.17 (d, J ¼ 8.4 Hz, 2H, ArH); ¹³C NMR (CDCl₃, 75

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MHz, d ppm): 38.82 (CH₂), 55.69 (OCH₃), 56.20 (OCH₃), 56.34 bottomed ask and dissolved in ethyl acetate–methanol

(OCH₃), 109.05, 111.60, 114.32 (2 ꢃ C), 119.52, 128.23, 130.02 (2 mixture (8 : 2). The mixture was ushed with nitrogen gas and

ꢃ C), 130.75, 131.13, 132.79, 148.84, 149.43, 158.49; ESIMS palladium charcoal (Pd/C, 5% wt) (0.08 g) was added and

(C₁₈H₂₀O₃): m/z ¼ 283 [M ꢁ H]⁺, 285 [M + H]⁺, 307 [M + Na]⁺.

hydrogen gas was passed to it for 1 h. The progress of reaction

1,2,3-Trimethoxy-5-(3-(4-methoxyphenyl)prop-1-enyl)benzene was monitored by TLC. Aer completion of the reaction, the

(14h). Yield: (0.38 g), 48%; m.p. 69–71 ^ꢀC; R_f: 0.78 (30% ethyl solvent was evaporated and crude material was worked up using

acetate–hexane); IR (KBr, n_maxcm^ꢁ1): 2936, 2835, 1583, 1508, ethyl acetate and water. The organic layer was the separated,

1459, 1419, 1243, 1123, 1027, 819; ¹H NMR (CDCl₃, 300 MHz, d dried anhydrous sodium sulphate (Na₂SO₄) and concentrated.

ppm): 3.51 (d, J ¼ 6.0 Hz, 2H, CH₂), 3.82–3.96 (m, 12H, 4 ꢃ The crude was puried by column chromatography on silica gel

OCH₃), 6.23–6.32 (m, 1H, CH), 6.52 (d, J ¼ 15.6 Hz, 1H, CH),6.61 (100–200 mesh size) using ethyl acetate–hexane (12 : 88) as

(s, 2H, ArH), 6.84–6.91 (m, 2H, ArH), 7.12–7.20 (m, 2H, ArH); ¹³

C

eluents which yielded pure compound 15 as white solid. Yield:

NMR (CDCl₃, 75 MHz, d ppm): 38.77 (CH₂), 55.69 (OCH₃), 56.50 (0.68 g), 85%; m.p. 56–57 ^ꢀC; R_f: 0.80 (30% ethyl acetate–

(2 ꢃ OCH₃), 61.32 (OCH₃), 103.59 (2 ꢃ C), 114.35 (2 ꢃ C), 129.69, hexane); IR (KBr, n_maxcm^ꢁ1): 2933, 2837, 1588, 1509, 1457, 1242,

1

130.06 (2 ꢃ C), 131.00, 132.49, 133.70, 153.64 (3 ꢃ C), 158.54; 1125, 1006, 829; H NMR (CDCl₃, 300 MHz, d ppm): 1.90–2.00

ESIMS (C₁₉H₂₂O₄): m/z ¼ 337 [M + Na]⁺.

(m, 2H, CH₂), 2.59–2.66 (m, 4H, 2 ꢃ CH₂), 3.82–3.87 (m, 12H, 4

1,2-Dimethoxy-4-(3-(3,4,5-trimethoxyphenyl)prop-1-enyl)- ꢃ OCH₃), 6.42 (s, 2H, ArH), 6.87 (d, J ¼ 8.7 Hz, 2H, ArH), 7.14 (d,

benzene (14i). Yield: (0.40 g), 51%; m.p. 67–68 ^ꢀC; R_f: 0.71 (30% J ¼ 8.4 Hz, 2H, ArH); ¹³C NMR (CDCl₃, 75 MHz, d ppm): 33.58

ethyl acetate–hexane); IR (KBr, n_maxcm^ꢁ1): 2934, 2835, 1588, (CH₂), 34.96 (CH₂), 36.19 (CH₂), 55.66 (OCH₃), 56.47 (2 ꢃ

1

1510, 1458, 1236, 1127, 1024, 823; H NMR (CDCl₃, 300 MHz, d OCH₃), 61.52 (OCH₃), 105.75 (2 ꢃ C), 114.16 (2 ꢃ C), 129.72 (2 ꢃ

ppm): 3.47 (d, J ¼ 6.6 Hz, 2H, CH₂), 3.82–3.88 (m, 15H, 5 ꢃ C), 134.65, 136.50, 138.54, 153.48 (2 ꢃ C), 158.19; ESIMS

OCH₃), 6.16–6.24 (m, 1H, CH), 6.37–6.45 (m, 3H, CH and (C₁₉H₂₄O₄): m/z ¼ 316 [M]⁺, 339 [M + Na]⁺.

ArH), 6.72 (d, J ¼ 8.4 Hz, 1H, ArH), 6.80 (d, J ¼ 9.3 Hz, 1H,

1,2-Dimethoxy-4-(3-(3,4,5-trimethoxyphenyl)propyl)benzene

ArH), 6.90 (d, J ¼ 8.4 Hz, 1H, ArH); ¹³C NMR (CDCl₃, 75 MHz, (15b). Yield: (0.72 g), 90%; m.p. 52–53 C; R_f: 0.30 (30% ethyl

d ppm): 40.09 (CH₂), 56.25 (OCH₃), 56.35 (OCH₃), 56.53 (2 ꢃ acetate–hexane); IR (KBr, n_maxcm^ꢁ1): 2939, 2837, 1589, 1514,

OCH₃), 61.25 (OCH₃), 106.10 (2 ꢃ C), 109.21, 111.67, 119.58, 1463, 1239, 1130, 1029, 1003, 823, 766; ¹H NMR (CDCl₃, 300

127.50, 130.98, 131.18, 136.48, 148.99, 149.49, 153.68 (3 ꢃ MHz, d ppm): 1.90–2.01 (m, 2H, CH₂), 2.59–2.66 (m, 4H, 2 ꢃ

C); ESIMS (C₂₀H₂₄O₅): m/z ¼ 367 [M + Na]⁺, 369 [M + 2 + Na]⁺. CH₂), 3.85–3.89 (m, 12H, 4 ꢃ OCH₃), 6.42 (s, 2H, ArH), 6.74–6.77

4-(3,4,5-Trimethoxycinnamyl)phenol (14j). Yield: (0.41 g), (m, 2H, ArH), 6.81–6.84 (d, J ¼ 7.8 Hz, 1H, ArH); ¹³C NMR

ꢀ

52%; m.p. 124–125 C; R_f: 0.46 (30% ethyl acetate–hexane); IR (CDCl₃, 75 MHz, d ppm): 33.48, 33.46, 36.21, 56.26 (OCH₃),

(KBr, n_maxcm^ꢁ1): 3355, 3001, 2935, 2836, 1584, 1511, 1454, 1418, 56.36 (2 ꢃ OCH₃), 61.22 (OCH₃), 105.86 (2 ꢃ C), 111.77, 112.35,

1

1237, 1125, 1003, 830, 781; H NMR (CDCl₃, 300 MHz, d ppm): 120.67 (2 ꢃ C), 135.26, 136.61, 138.45, 147.66, 149.30, 153.50;

3.44 (dd, J ¼ 0.9 and 0.5 Hz, 2H, CH₂), 3.80–3.85 (m, 9H, 3 ꢃ ESIMS (C₂₀H₂₆O₅): m/z ¼ 347[M + H]⁺, 369 [M + Na]⁺.

OCH₃), 6.18–6.37 (m, 2H, CH), 6.57 (s, 2H, ArH), 6.78 (d, J ¼ 8.4

Hz, 2H, ArH), 7.10 (d, J ¼ 8.4 Hz, 2H, ArH); ESIMS (C₁₈H₂₀O₄):

2-Methoxy-4-(3-(3,4,5-trimethoxyphenyl)propyl)phenol (15c)

m/z ¼ 301 [M + H]⁺, 323 [M + Na]⁺.

Yield: (0.63 g), 78%; m.p. 83–84 ^ꢀC; R_f: 0.45 (30% ethyl acetate–

4-(4-Methoxycinnamyl)phenol (14l). Yield: (0.39 g), 50%;

1

hexane); H NMR (CDCl₃, 300 MHz, d ppm): 1.79–1.89 (m, 2H,

m.p. 73–74 ^ꢀC; R_f: 0.43 (30% ethyl acetate–hexane); IR (KBr, n_max

CH₂), 2.48–2.53 (t, J ¼ 2.7 Hz, 4H, 2 ꢃ CH₂), 3.73–3.82 (m, 12H, 4

1

cm^ꢁ1): 3370, 1605, 1511, 1242, 1026, 831; H NMR (CDCl₃, 300

ꢃ OCH₃), 5.51 (s, 1H, CH), 6.32 (s, 2H, ArH), 6.57–6.60 (dd, J ¼

MHz, d ppm): 3.39 (d, J ¼ 6.6 Hz, 2H, CH₂), 3.73 (s, 3H, OCH₃),

4.95 (bs, 1H, OH), 6.08–6.17 (m, 1H, CH), 6.31 (d, J ¼ 15.9 Hz,

1H, CH), 6.70–6.79 (m, 4H, ArH), 6.95 (d, J ¼ 8.4 Hz, 2H, ArH),

7.19–7.24 (m, 2H, ArH); ¹³C NMR (CDCl₃, 75 MHz, d ppm): 38.84

(CH₂), 55.74 (OCH₃), 114.38 (2 ꢃ C), 115.71 (2 ꢃ C), 127.64 (2 ꢃ

C), 127.94, 130.20 (2 ꢃ C), 130.54, 130.84, 133.00, 154.31,

159.19; ESIMS (C₁₆H₁₆O₂): m/z ¼ 293 [M + Na]⁺, 309 [M + K]⁺.

3-(3,4,5-Trimethoxyphenyl)-1-(4-hydroxy-3-methoxyphenyl)-

prop-1-ene (14m). Yield: (0.45 g), 57%; oil; R_f: 0.30 (30% ethyl

1.8 and 1.8 Hz, 1H, ArH), 6.71–6.75(m, 2H, ArH); ¹³C NMR

(CDCl₃, 75 MHz, d ppm): 33.35, 35.20, 36.13, 56.42, 56.48 (2 ꢃ

OCH₃), 61.23, 105.83 (2 ꢃ C), 111.04, 115.09, 120.13, 135.97,

136.56, 138.51, 145.16, 145.91, 153.48 (2

ꢃ

C); ESIMS

(C₁₉H₂₄O₅): m/z ¼ 333 [M + H]⁺.

General procedure for the synthesis of compounds (17a–e)

2-(4-Hydroxy-3-methoxybenzylidene)-3,4-dihydro-6-methoxy-

acetate–hexane); ¹H NMR (CDCl₃, 300 MHz, d ppm): 3.39 (d, J ¼ naphthalen-1(2H)-one (17a). In

a round bottomed ask

6.3 Hz, 2H, CH₂), 3.75–3.86 (m, 12H, 4 ꢃ OCH₃), 5.54 (s, 1H, compound 16 (R₁¼ R₂¼ H, n ¼ 2) (2.00 g, 11.36 mmol) was

OH), 6.04–6.14 (m, 1H, CH), 6.29–6.34 (m, 1H, CH), 6.38 (s, 2H, dissolved into methanol (20 mL) and methanolic KOH (10%, 20

ArH), 6.76–6.82 (m, 3H, ArH); ESIMS (C₁₉H₂₂O₅): m/z ¼ 331 mL) was added to this solution drop wise on ice bath. Aer 20

[M + H]⁺, 353 [M + Na]⁺.

minutes, compound 10 (R⁰¼ OCH₃, R ¼ H, 2.63 g, 11.36 mmol)

dissolved in methanol (15 mL) was added to reaction mixture.

The reaction mixture was allowed to stir at ice bath for 30

minutes and aerwards at room temperature for 12 h. The

General procedure for the synthesis of (15a–c)

1,2,3-Trimethoxy-5-(3-(4-methoxyphenyl)propyl)benzene progress of reaction was monitored using TLC. Aer completion

(15a). Compound 14k (0.80 g, 2.54 mmol) was taken in a round of reaction, solvent was evaporated followed by drop wise

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addition of dilute HCl and pH of the content was adjusted to 132.67, 133.56, 145.02, 150.00, 155.62, 161.02, 193.57 (C]O);

acidic. The content was extracted with ethyl acetate. The organic ESIMS (C₁₉H₁₈O₄): m/z ¼ 333 [M + Na]⁺.

layer was then separated and dried over anhydrous sodium

sulphate (Na₂SO₄) and concentrated. The crude material was

puried by crystallization by methanol which yielded pure

General procedure for the synthesis of compounds (18a–e)

compound 17a as yellow solid. Yield: (2.53 g), 72%; m.p. 129–

130 ^ꢀC; R_f: 0.18 (20% ethyl acetate–hexane); IR (KBr, n_maxcm^ꢁ1):

2-(4-Hydroxy-3-methoxybenzyl)-3,4-dihydro-6-methoxynaph-

3182, 1637, 1597, 1556, 1522, 1255, 1127, 1093, 1034, 867, 826, thalen-1(2H)-one (18a). Compound 17a (1.00 g, 3.23 mmol) was

765; ¹H NMR (CDCl₃, 300 MHz, d ppm): 2.88–2.93(m, 2H, CH₂), taken in a round bottomed ask and dissolved in ethyl acetate–

3.12 (bs, 2H, CH₂), 3.86(s, 3H, OCH₃), 3.90(s, 3H, OCH₃), 5.93(s, methanol mixture (8 : 2). The mixture was ushed with nitrogen

1H, OH), 6.70(s, 1H, ArH), 6.86 (dd, J ¼ 2.4 &2.1 Hz, 1H, ArH), gas and palladium charcoal (Pd/C, 5% wt) (0.10 g) was added

6.96–7.03 (m, 3H, ArH), 7.78 (s, 1H, ArH), 8.09 (d, J ¼ 8.7 Hz, 1H, and hydrogen gas was passed to it for 3 h. The progress of

ArH); ¹³C NMR (CDCl₃, 75 MHz, d ppm): 27.71 (CH₂), 29.61 reaction was monitored by TLC. Aer completion of the reac-

(CH₂), 55.83 (OCH₃), 56.83(OCH₃), 112.66, 113.19, 113.65, tion, the solvent was evaporated and crude material was worked

114.85, 124.08, 127.58, 128.75, 131.09, 134.14, 136.77, 145.95, up using ethyl acetate and water. The organic layer was the

146.70, 146.82, 163.90, 187.15(C]O); ESIMS (C₁₉H1₈O₄): m/z ¼ separated, dried anhydrous sodium sulphate (Na₂SO₄) and

309[M ꢁ 1]⁺, 333 [M + Na]⁺.

concentrated. The crude was puried by column chromatog-

2-(4-Hydroxy-3-methoxybenzylidene)-2,3-dihydro-5-methoxy- raphy on silica gel (100–200 mesh size) using ethyl acetate–

inden-1-one (17b). Yield: (3.02 g), 83%; m.p. 199–201 ^ꢀC; R_f: 0.09 hexane (12 : 88) as eluents which yielded pure compound 18a as

(20% ethyl acetate–hexane); IR (KBr, n_maxcm^ꢁ1): 3490, 1681, white solid. Yield: (0.72 g), 72%; m.p. 114–115 ^ꢀC; R_f: 0.40 (30%

1624, 1589, 1521, 1267, 1092, 1028, 837, 811; H NMR (DMSO- ethyl acetate–hexane); IR (KBr, n_maxcm^ꢁ1): 3353, 2932, 1663,

1

d₆, 300 MHz, d ppm): 3.75–3.79 (m, 6H, 2 ꢃ OCH₃), 3.94 (bs, 2H, 850; ¹H NMR (CDCl₃, 300 MHz, d ppm): 1.67 (s, 2H, CH₂), 2.56–

CH₂), 6.79–6.82 (d, J ¼ 8.1 Hz, ArH), 6.90–6.93 (d, J ¼ 8.4 HZ, 1H, 2.68 (m, 2H, CH₂), 2.85–2.89 (m, 2H, CH₂), 3.35–3.39 (m, 1H,

ArH), 7.09–7.14 (m, 2H, ArH), 7.21–7.47 (m, 4H, CH and ArH), CH), 3.84–3.86 (m, 6H, 2 ꢃ OCH₃), 5.53 (s, 1H, OH), 6.66–6.74

7.59–7.62 (d, J ¼ 8.4 Hz, 1H, ArH); ¹³C NMR (DMSO-d₆, 75 MHz, (m, 3H, ArH), 6.80–6.84 (m, 2H, ArH), 8.03 (d, J ¼ 9.0 Hz, 1H,

d ppm): 32.80, 56.52, 56.60, 110.92, 115.23, 149.53, 148.67, ArH); ¹³C NMR (CDCl₃, 75 MHz, d ppm): 28.00 (CH₂), 29.29

133.24, 133.12, 133.24, 148.67, 149.53, 153.60, 165.53, 192.53 (CH₂), 35.87(CH₂), 49.73 (CH), 55.81 (OCH₃), 56.32 (OCH₃),

(C]O); ESIMS (C₁₈H₁₆O₄): m/z ¼ 297 [M + H]⁺, 323 [M + Na]⁺.

112.11, 112.85, 113.59, 114.54, 122.35, 126.55, 130.38, 132.41,

2-(4-Hydroxy-3-methoxybenzylidene)-2,3-dihydro-5,6-dime- 144.36, 146.87, 146.95, 163.90, 198.75 (C]O); ESIMS

thoxyinden-1-one (17c). Yield: (2.92 g), 86%; m.p. 140–141 C; (C₁₉H₂₀O₄): m/z ¼ 335 [M + Na]⁺.

ꢀ

R_f: 0.11 (30% ethyl acetate–hexane); IR (KBr, n_maxcm^ꢁ1): 3424,

2-(4-Hydroxy-3-methoxybenzyl)-2,3-dihydro-5-methoxyinden-

1

1672, 1578, 1505, 1311, 817, 714; H NMR (CDCl₃, 300 MHz, d 1-one (18b). Yield: (0.59 g), 59%; m.p. 120–121 ^ꢀC; R_f: 0.37 (40%

ppm): 3.79–3.85 (m, 11H, 3 ꢃ OCH₃and CH₂), 6.77–6.87 (m, 2H, ethyl acetate–hexane); IR (KBr, n_maxcm^ꢁ1): 3376, 1681, 1593,

1

ArH), 7.01–7.07 (m, 2H, ArH), 7.16 (s, 1H, CH), 7.36 (s, 1H, ArH); 1517, 1251, 849, 814; H NMR (CDCl₃, 300 MHz, d ppm): 2.63

¹³C NMR (CDCl₃, 75 MHz, d ppm): 32.41 (CH₂), 55.28 (OCH₃), (dd, J ¼ 9.6 and 9.9 Hz, 1H, CH of CH₂), 2.80 (dd, J ¼ 3.0 and 3.0

56.42 (OCH₃), 58.58 (OCH₃), 105.26, 107.65, 113.96, 116.03, Hz, 1H, CH of CH₂), 2.89–2.98 (m, 1H, CH), 3.10 (dd, J ¼ 7.5 and

125.12, 127.86, 131.50, 132.91, 133.21, 144.94, 147.86, 148.57, 7.5 Hz, 1H, CH of CH₂), 3.22–3.28 (dd, J ¼ 3.9 and 4.2 Hz, 1H,

149.85, 155.48, 193.45 (C]O); ESIMS (C₁₉H₁₈O₅): m/z ¼ 327 [M CH of CH₂), 3.84 (s, 6H, OCH₃), 5.55 (s, 1H, OH), 6.68–6.73 (m,

+ H]⁺, 349 [M + Na]⁺.

2H, ArH), 6.81–6.83 (m, 2H, ArH), 6.88 (d, J ¼ 8.4 Hz, 1H, ArH),

2-(4-Methoxybenzylidene)-2,3-dihydro-5-methoxyinden-1- 7.69 (d, J ¼ 8.4 Hz, 1H, ArH); ¹³C NMR (CDCl₃, 75 MHz, d ppm):

ꢀ

one (17d). Yield: (2.55 g), 74%; m.p. 145–146 C; R_f: 0.15 (20% 31.29 (CH₂), 32.44 (CH₂), 49.67, 56.01 (OCH₃), 56.29 (OCH₃),

ethyl acetate–hexane); IR (KBr, n_maxcm^ꢁ1): 1684, 1597, 1504, 110.09, 111.84, 114.60, 115.82, 122.03, 126.01, 130.30, 131.91,

1256, 1125, 1022, 808; ¹H NMR (CDCl₃, 300 MHz, d ppm): 3.84– 144.52, 146.92, 157.16, 165.84, 206.63 (C]O); ESIMS

3.92 (m, 8H, CH and 2 ꢃ OCH₃), 6.91–6.97 (m, 4H, ArH), 7.55– (C₁₈H₁₈O₄): m/z ¼ 299 [M + H]⁺, 321 [M + Na]⁺.

7.60 (m, CH and ArH), 7.82 (d, J ¼ 8.4 Hz, 1H, ArH); ¹³C NMR

2-(4-Hydroxy-3-methoxybenzyl)-2,3-dihydro-5,6-dimethoxyinden-

(CDCl₃, 75 MHz, d ppm): 32.92 (CH₂), 55.77 (OCH₃), 56.05 1-one (18c). Yield: (0.70 g), 70%; m.p. 137–138 ^ꢀC; R_f: 0.27 (30%

(OCH₃), 110.13, 114.81 (2 ꢃ C), 115.49, 126.42, 128.71, 132.03, ethyl acetate–hexane); IR (KBr, n_maxcm^ꢁ1): 3387, 2988, 2939,

132.72 (2 ꢃ C), 132.91, 133.34, 152.76, 161.03, 165.44, 193.27 1676, 1216, 1035, 972, 846, 803, 665: ¹H NMR (CDCl₃, 300 MHz,

(C]O); ESIMS (C₁₈H₁₆O₃): m/z ¼ 303 [M + Na]⁺, 319 [M + K]⁺.

d ppm): 2.57–2.65 (m, 1H, CH of CH₂), 2.76 (d, J ¼ 16.8 Hz, 1H,

2-(4-Methoxybenzylidene)-2,3-dihydro-5,6-dimethoxyinden- CH), 2.93 (bs, 1H, CH), 3.04–3.09 (m, 1H, CH), 3.25 (d, J ¼ 13.8,

1-one (17e). Yield: (2.90 g), 90%; m.p. 191–192 ^ꢀC; R_f: 0.46 (30% Hz, 1H, CH), 3.83–3.92 (m, 9H, 3 ꢃ OCH₃), 5.06 (s, 1H, OH),

ethyl acetate–hexane); IR (KBr, n_maxcm^ꢁ1): 1684, 1597, 1504, 6.68–6.73 (m, 2H, ArH), 6.84 (bs, 2H, ArH), 7.25 (s, 1H, ArH); ¹³

C

1256, 1125, 1022, 808; ¹H NMR (CDCl₃, 300 MHz, d ppm): 3.83– NMR (CDCl₃, 75 MHz, d ppm): 32.17 (CH₂), 37.39 (CH₂), 49.79,

4.20 (m, 11H, CH₂and 3 ꢃ OCH₃), 6.92–6.94 (m, 3H, ArH), 7.29 55.29 (OCH₃), 56.49 (OCH₃), 56.59 (OCH₃), 104.79, 107.86,

(s, 1H, CH), 7.52–7.58 (m, 3H, ArH); ¹³C NMR (CDCl₃, 75 MHz, d 111.86, 114.62, 122.00, 129.71, 131.95, 144.53, 146.92, 149.51,

ppm): 32.55 (CH₂), 55.76 (OCH₃), 56.53 (OCH₃), 56.64 (OCH₃), 149.91, 156.04, 207.12 (C]O); ESIMS (C₁₉H₂₀O₅): m/z ¼ 329

105.49, 107.61, 114.81 (2 ꢃ C), 128.75, 131.68, 132.60 (2 ꢃ C), [M + H]⁺.

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gel (100–200 mesh size) using hexane as eluents which yielded

pure compound 20a as white solid. Yield: (0.75 g), 82%; m.p.

72–73 ^ꢀC; R_f: 0.50 (20% ethyl acetate–hexane); IR (KBr, n_max

cm^ꢁ1): 3386, 2935, 1607, 1511, 1432, 1266, 1240, 1152, 1033,

802, 738; ¹H NMR (CDCl₃, 300 MHz, d ppm): 2.17 (t, J ¼ 7.9 Hz,

2H, CH₂), 2.76 (t, J ¼ 7.9 Hz, 2H, CH₂), 3.42 (s, 2H, CH₂), 3.79 (s,

3H, OCH₃), 3.86 (s, 3H, OCH₃), 5.53 (s, 1H, OH), 6.21 (s, 1H, CH),

6.67–6.73 (m, 4H, ArH), 6.861 (d, J ¼ 8.4 Hz, 1H, ArH), 6.94 (d, J

¼ 8.1 Hz, 1H, ArH); ¹³C NMR (CDCl₃, 75 MHz, d ppm): 27.07

(CH₂), 29.15 (CH₂), 43.83 (CH₂), 55.69 (OCH₃), 56.32 (OCH₃),

111.51, 111.80, 113.98, 114.54, 122.17, 123.44, 126.89, 128.36,

131.94, 136.55, 138.93, 144.41, 146.87, 158.70; ESIMS

(C₁₉H₂₀O₃): m/z ¼ 319 [M + Na]⁺, 335 [M + K]⁺.

2-(4-Methoxybenzyl)-2,3-dihydro-5-methoxyinden-1-one (18d).

Yield: (0.87 g), 87%; m.p. 85–86 C; R_f: 0.57 (30% ethyl acetate–

ꢀ

hexane); IR (KBr, n_maxcm^ꢁ1): 2916, 2841, 1689, 1251, 1023, 840,

689; ¹H NMR (CDCl₃, 300 MHz, d ppm): 2.58–2.66 (m, 1H, CH of

CH₂)2.78 (dd, J ¼ 3.6 and 3.6 Hz, 1H, CH of CH₂), 2.89–2.98 (m,

1H, CH), 3.09 (dd, J ¼ 7.5 and 7.8 Hz, 1H, CH of CH₂), 3.28 (dd, J

¼ 4.2 and 4.2 Hz, 1H, CH of CH₂), 3.78 (s, 3H, OCH₃), 3.85 (s, 3H,

OCH₃), 6.80–6.90 (m, 4H, ArH), 7.14 (d, J ¼ 8.4 Hz, 2H, ArH), 7.69

(d, J ¼ 8.4 Hz, 1H, ArH); ¹³C NMR (CDCl₃, 75 MHz, d ppm):

32.50(CH₂), 36.68 (CH₂), 49.61 (CH), 55.63 (OCH₃), 55.99 (OCH₃),

110.11, 114.31 (2 ꢃ C), 115.75, 126.04, 130.27 (3 ꢃ C), 132.10,

157.04, 158.54, 165.81, 206.46 (C]O); ESIMS (C₁₈H₁₈O₃): m/z ¼

283 [M + H]⁺, 305 [M + Na]⁺.

2-Methoxy-4-((6-methoxy-1H-inden-2-yl)methyl)phenol (20b).

Yield: (0.60 g), 66%; m.p. 108–109 ^ꢀC; R_f: 0.58 (30% ethyl

acetate–hexane); IR (KBr, n_maxcm^ꢁ1): 3434, 2932, 1604, 1515,

1473, 1275, 1237, 1034, 869, 821; ¹H NMR (acetone-d₆, 300 MHz,

d ppm): 3.22 (bs, 2H, CH₂), 3.68 (s, 2H, CH₂), 3.74 (s, 3H, OCH₃),

3.80 (s, 3H, OCH₃), 6.41 (s, 1H, CH), 6.69–6.78 (m, 4H, ArH), 6.85

(bs, 1H, ArH), 6.96 (bs, 1H, ArH), 7.12 (d, J ¼ 8.1 Hz, 1H, ArH),

7.36 (bs, 1H, OH); ¹³C NMR (acetone-d₆, 75 MHz, d ppm): 37.43

(CH₂), 40.85 (CH₂), 55.16 (OCH₃), 55.74 (OCH₃), 110.60, 111.92,

112.73, 115.22, 120.55, 121.60, 126.79, 132.07, 138.85, 145.36,

145.66, 147.80, 148.24, 157.87; ESIMS (C₁₈H₁₈O₃): m/z ¼ 283

[M + H]⁺, 305 [M + Na]⁺.

2-(4-Methoxybenzyl)-2,3-dihydro-5,6-dimethoxyinden-1-one

(18e). Yield: (0.73 g), 73%; m.p. 122–123 ^ꢀC; R_f: 0.13 (30% ethyl

acetate–hexane); IR (KBr, n_maxcm^ꢁ1): 2947, 2926, 1691, 1602,

1

1506, 1464, 1259, 810, 778; H NMR (CDCl₃, 300 MHz, d ppm):

2.58–2.65 (m, 1H, CH of CH₂), 2.71–2.78 (dd, J ¼ 3.0 and 3.0 Hz,

1H, CH of CH₂), 2.89–2.97 (m, 1H, CH), 3.01–3.09 (m, 1H, CH of

CH₂), 3.24–3.30 (dd, J ¼ 4.2 and 4.2 Hz, 1H, CH of CH₂), 3.77 (s,

3H, OCH₃), 3.82–3.925 (m, 6H, 2 ꢃ OCH₃), 6.81 (d, J ¼ 8.7 Hz,

3H, ArH), 7.12–7.18 (m, 3H, ArH); ¹³C NMR (CDCl₃, 75 MHz, d

ppm): 32.18 (CH₂), 36.76 (CH₂), 49.71 (CH), 55.63 (OCH₃), 56.49

(OCH₃), 56.57 (OCH₃), 104.83, 107.83, 114.28 (2 ꢃ C), 129.72,

130.26 (2 ꢃ C), 132.11, 149.41, 149.88, 155.99, 158.51, 207.04

(C]O); ESIMS (C₁₉H₂₀O₄): m/z ¼ 313 [M + H]⁺, 335 [M + Na]⁺.

2-methoxy-4-((5,6-dimethoxy-1H-inden-2-yl)methyl)phenol

(20c). Yield: (0.65 g), 71%; m.p. 116–117 ^ꢀC; R_f: 0.38 (30% ethyl

acetate–hexane); IR (KBr, n_maxcm^ꢁ1): 3412. 2963, 2924, 1607,

1513, 1487, 1461, 1298, 1269, 855; ¹H NMR (acetone-d₆, 300

MHz, d ppm): 3.18 (s, 2H, CH₂), 3.68 (s, 2H, CH₂), 3.75–3.89 (m,

9H, 3 ꢃ OCH₃), 6.39 (s, 1H, CH), 6.67–6.77 (m, 2H, ArH), 6.84–

6.89 (m, 2H, ArH), 7.15 (s, 1H, ArH); ¹³C NMR (acetone-d₆, 75

MHz, d ppm): 37.43 (CH₂), 40.73 (CH₂), 55.77 (OCH₃), 55.95

(OCH₃), 56.22 (OCH₃), 105.56, 109.72, 112.75, 115.21, 121.58,

127.17, 132.19, 136.27, 138.86, 145.37, 147.58, 147.81, 149.15,

149.30; ESIMS (C₁₉H₂₀O₄): m/z ¼ 313 [M + H]⁺, 335 [M + Na]⁺.

2-(4-methoxybenzyl)-6-methoxy-1H-indene (20d). Yield: (0.45

General procedure for the synthesis of compounds (19a–e)

In a round bottomed ask, compound 18a (0.60 g, 1.92 mmol)

was dissolved in methanol and kept at 0 ^ꢀC for 15–20 minutes.

To this mixture sodium borohydride (NaBH_4,0.22 g, 5.76

mmol), was added and reaction was transferred to room

temperature aer half an hour. The progress of reaction was

monitored by TLC (30% ethyl acetate–hexane). Aer completion

of reaction, solvent was taken oﬀ and the reaction mixture was

treated with NH₄Cl and worked up using ethyl acetate and

water. The organic layer was the separated, dried anhydrous

sodium sulphate (Na₂SO₄) and concentrated. The crude solid

material was puried by washing it with hexane which yielded

pure compound 19a as white solid in 98% (0.54 g) yield which

was further processed for hydrolysis as such. The experimental

procedure used for synthesis of compound 19b–m is same as

described above. The molar ratio of reactants was same for

synthesis of all derivatives.

ꢀ

g), 50%; m.p. 83–84 C; R_f: 0.6 (30% ethyl acetate–hexane); IR

(KBr, n_maxcm^ꢁ1): 3006, 2927, 2837, 1606, 1511, 1464, 1232, 1243,

1179, 1106, 1030, 859, 809, 745; ¹H NMR (acetone-D₆, 300 MHz,

d ppm): 3.21 (s, 2H, CH₂), 3.70–3.83 (m, 8H, CH₂and 2 ꢃ OCH₃),

6.39 (s, 1H, ArH), 6.75 (d, J ¼ 8.1 Hz, 1H, ArH), 6.84–6.96 (m, 3H,

ArH), 7.11–7.18 (m, 3H, CH and ArH); ¹³C NMR (acetone-D₆, 75

MHz, d ppm): 36.89 (CH₂), 40.83 (CH₂), 54.96 (OCH₃), 55.16

(OCH₃), 110.60, 111.95, 114.16 (2 ꢃ C), 120.56, 120.89, 126.89,

130.08 (2 ꢃ C), 132.70, 145.63, 148.12, 157.92, 158.68; ESIMS

(C₁₈H₁₈O₂): m/z ¼ 267 [M + H]⁺, 265 [M ꢁ H]⁺.

General procedure for the synthesis of compounds (20a–e)

4-((1,2-Dihydro-7-methoxynaphthalen-3-yl)methyl)-2-methoxy-

2-(4-methoxybenzyl)-5,6-dimethoxy-1H-indene (20e). Yield:

phenol (20a). In a round bottomed ask, compound 19a (0.97 g, (0.57 g), 62%; m.p. 94.0–95 ^ꢀC; R_f: 0.6 (30% ethyl acetate–

2.93 mmol) was dissolved in ethanol and conc. HCl (1 mL) was hexane); IR (KBr, n_maxcm^ꢁ1): 2941, 2834, 1609, 1507, 1460, 1320,

1

added to it. The reaction mixture was transferred for reux. The 1242, 1101, 1033, 853, 823; H NMR (CDCl₃, 300 MHz, d ppm):

progress of reaction was monitored by TLC (30% ethyl acetate– 3.20 (s, 2H, CH₂), 3.79–3.87 (m, 11H, CH₂and 3 ꢃ OCH₃), 6.39

hexane). Aer completion of reaction, solvent was taken oﬀ and (s, 1H, CH), 6.83–6.85 (m, 3H, ArH), 6.95 (bs, 1H, ArH), 7.13 (d, J

the reaction mixture was worked up using ethyl acetate and ¼ 8.4 Hz, 2H, ArH); ¹³C NMR (acetone-D₆, 75 MHz, d ppm):

water. The organic layer was the separated, dried over anhy- 36.89 (CH₂), 40.70 (CH₂), 54.96 (OCH₃), 55.91 (OCH₃), 56.17

drous sodium sulphate (Na₂SO₄) and concentrated. The crude (OCH₃), 105.46, 109.60, 114.13 (2 ꢃ C), 127.27, 130.07 (2 ꢃ C),

solid material was puried by column chromatography on silica

RSC Adv., 2014, 4, 35171–35185 | 35183

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132.81, 136.20, 138.76, 147.55, 149.03, 149.27, 158.64; ESIMS ml per well) for 15 min in dark. Images were acquired with 20ꢃ

(C₁₉H₂₀O₃): m/z ¼ 297 [M + H]⁺, 319 [M + Na]⁺.

objective using a uorescent microscope (Nikon, Japan).

In vitro cytotoxicity in THP-1 cells. The compounds were

tested for its cytotoxicity against THP-1 cell line in vitro using

resazurin assay (Roy et al., 2011). Briey, 10⁴–10⁶cells per well

were seeded in 96-well plate in 200 ml RPMI supplemented with

heat inactivated fetal bovine serum (10% v/v) and incubated at

37 ^ꢀC with 5% CO₂for overnight. Cells were exposed to diﬀerent

dilutions of test compounds and standard (Rifampin) in trip-

licate ranging from 400 to 6.25 mM concentration with two fold

dilutions. Aer 48 h 20 ml of resazurin (0.02% w/v) was added in

each well and further incubated for 4–5 h. The colour change

from purple to pink was assessed visually and uorescence was

measured at 530 ꢂ 25 nm and 590 ꢂ 25 nm for excitation and

emission respectively in Synergy Biotek plate reader. CC₅₀

values (50% cytotoxic concentrations) were calculated by plot-

ting uorescence values using Microso excel template.

HPLC analysis

Liquid chromatography based generic methods are widely

applicable for the pharmaceutical industry to identify, quantify

and determine the purity of small organic compounds. The

purity of compounds was determined using high-low chro-

matographic approach. LC-PDA-MS (Shimadzu, Japan) consist-

ing of an analytical column (Phenomenex, C₁₈250 ꢃ 4.6 mm, 5

mm), pumps (LC-20AD), injector and PDA (SPD-M20A), was

used for analysis. Gradient elution covering a wide range of

solvent polarity viz. methanol–water, acetonitrile–water with

and without acid additives, was tried on diverse stationary

phases. Finally, a better separation was achieved with a mobile

phase composition of acetonitrile–water (80 : 20, v/v). A ow

rate of 1.0 mL min^ꢁ1and column temperature of 27 ^ꢀC was

maintained throughout the run.

Ligand and protein preparation for docking experiments

In vitro anticancer activity

Estrogen receptor (PDB: 1A52; 17-b-estradiol bound) and b-

Assessment of cell growth inhibition. In vitro anticancer tubulin (PDB: 1SA0; colchicine bound) were retrieved from

activity of test compounds was studied by Sulphorhodamine B RCSB Protein Data Bank. Ligand Explorer viewer and PDBsum

(SRB) dye based plate assay. In brief, 10⁴cells per well were (http://www.ebi.ac.uk/pdbsum/) were used to inspect the

ꢀ

added in 96-well culture plates and incubated at 37 C in 5% binding site residues and their interactions with bound ligands.

CO₂concentration. Aer overnight incubation of cells, serial This showed that 17b-estradiol has interactions via hydrogen

dilutions of test compound were added to the wells. Untreated bond with His524, Arg394 and Glu353 in bound state with chain

cells served as control. Aer 48 h, cells were xed with ice-cold A. Surrounding residues at this active site included Leu346,

Tri-chloroacetic acid (50% w/v, 100 ml per well), stained with Leu387, Leu391, Phe404, Met388, Ala350, Ile424 and Leu525.

SRB (0.4% w/v in 1% acetic acid, 50 ml per well), washed and Whereas, colchicine bound active site of b-tubulin protein

air-dried. Bound dye was solubilised with 10 mM Tris base (150 showed colchicine interaction via hydrogen bond with Cys241

ml per well) and absorbance was read at 540 nm on a plate in bound state with chain B. Surrounding residues at this active

reader. The cytotoxic eﬀect of compound was calculated as % site also included Leu255, Asn258, Ala316, Ile378, Leu242,

inhibition in cell growth as per formula: [1-(Absorbance of drug Val238, Ala250 and Lys254.

treated cells/Absorbance of untreated cells) ꢃ 100]. Determi-

nation of 50% inhibitory concentration (IC₅₀) was based on www.acdlabs.com) and the SMILES format of these structures

dose-response curves. were converted into 3D coordinate le in .pdb format using

The test compounds were drawn using chemsketch (http://

Cell cycle analysis by owcytometry. Cell cycle distribution online SMILE translation tool (http://cactus.nci.nih.gov/

was measured in concentration and time dependent manner by translate/). Energy minimization of these compounds was per-

ow cytometric analysis of PI-stained cellular DNA, as described formed using ligand preparation tool of Discovery studio 2.5

earlier.¹³Briey, MCF-7 cells (4 ꢃ 10⁵per well) were seeded in 6- and PRODRG server (http://davapc1.bioch.dundee.ac.wy.prodrg).

well culture plate and grown overnight (37 ^ꢀC, 5% CO₂). Estrogen receptor chain A and b-tubulin chain B were used for

Compound treated cells were harvested by trypsinization and docking studies aer removing heteroatoms and water mole-

xed (30 min, 4 ^ꢀC) with ice-cold 70% ethanol at indicated time cules. Proteins were energy minimized using Swiss-pdb viewer

points. The pellets were washed with PBS and re-suspended in a 4.01 (http://www.expasy.org/spdbv) by applying GROMOS96

solution containing PI (20 mg ml^ꢁ1), Triton X100 (0.1%) and force eld to compute energy and to execute energy minimiza-

RNase (1 mg ml^ꢁ1) in PBS. Aer incubation (45 min, in the dark, tion. AutoDock 4.2 soware (http://www.scripps.edu) was used

37 ^ꢀC), cells were analysed on a FACS Calibur ow cytometer (BD to execute docking experiments following Lamarckian Genetic

Biosciences). Distribution of cells in diﬀerent phases of cell algorithm (hybrid of genetic and local search algorithm) and

cycle was calculated using “Cell Quest” soware.

using default docking parameters. Best docked conformation of

Detection of fragmented nuclei by DAPI staining. To observe each ligand based on docking parameters and binding site

the nuclear morphology, cells (10⁴per well) were grown over- residues interactions were selected among top 10 docked

night in 96-well plates and treated with 14k at IC₅₀concentra- conformations of each ligand generated during docking. Lig-

tion. Aer 24 h incubation with test compound, cells were xed Plot Plus version v.1.4.4 (Roman Laskowski, 2009) was used to

with 4% formaldehyde (50 ml per well), washed with PBS and generate schematic diagram of protein-ligand interactions for a

permeabilized with 0.1% Triton X100 (50 ml per well). Aer given ligand in a PDB le. Colchicine and 2-methoxyestradiol

washing with PBS, cells were stained with DAPI (2 mg mL^ꢁ1, 50 (known tubulin inhibitors) were also docked on b-tubulin and

35184 | RSC Adv., 2014, 4, 35171–35185

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Acknowledgements

The authors thank the Director, CSIR-CIMAP and Council of

Scientic Industrial Research (CSIR) for nancial support. The

work was carried out under project ChemBio (BSC-203) to AG

and GAP 0115 (sponsored by DST, India) to JS.

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RSC Adv., 2014, 4, 35171–35185 | 35185

Article Doi

Syntheses of 2-methoxyestradiol and eugenol template based diarylpropenes as non-steroidal anticancer agents

DOI: 10.1039/c4ra03823a

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Authors:

Article abstract of DOI:10.1039/c4ra03823a

Full text of DOI:10.1039/c4ra03823a

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