Synthesis of 5-aryl-6-cinnamoyl-7-methyl-flavanones as novel antioxidants and antihyperlipidemics

Abstract

An economical and efficient one-pot synthesis of a series of novel 5-aryl-6-cinnamoyl-7-methyl-flavanones has been developed by simple refluxing of cinnamoyl chalcones with NaOAc in aqueous ethanol in quantitative yields. These flavanones were screened for their in vitro antioxidant and in vivo antidyslipidemic activities. Among 24 compounds screened, four compounds 28, 29, 30, and 48 showed significant antidyslipidemic activities. However, out of all the compounds, only compound 28 exhibited significant antioxidant activity and other compounds showed moderate antioxidant activities.

Keywords::

• Cholesterol lowering agents
• antidyslipidemic
• cinnamoyl chalcones
• diacetyl benzene
• sodium acetate

Introduction

Oxidative stress is intricately involved in the pathogenesis and development of several diseases and more particularly atherosclerosis¹. It is one of the important factors for the development and progression of CHD (coronary heart disease²). On the other hand, dyslipidemia is also a threat to serious cardiovascular problems, including atherosclerosis, stroke, and cardiac arrest. The most common dyslipidemia treatment, however, is a carefully regulated regimen of diet and exercise. More serious conditions may require a combination of exercise, medication, and surgery to prevent life-threatening complications³. Therefore, antioxidants and lipid lowering agents play a major role in prevention of CHD. Flavanones, the cyclic isomer of chalcones, are naturally occurring antioxidants and have been investigated in great detail for their antioxidant, hypolipidemic and free radical scavenging activities⁴. They are also known to play an important role in defence mechanism of plants against several toxicants, microbes and parasites⁵. They are associated with antibacterial, antifungal⁶, estrogen receptor modulatory^7,8, TNF-α inhibitory and hormone-dependent anticancer activities^9–11. Several naturally occurring and synthetic chalcones also possess most of the pharmacological activities of the flavanones^12–20. Therefore, it was envisaged to synthesize hybrid molecules where both the chalcone and flavanone skeletons are in the same molecule and screen them for their antioxidant antidyslipidemic activities (Figure 1). There are several methods to prepare flavanones involving the oxidative cyclization of 2′-hydroxychalcones using different reagents^21–25.

Figure 1.  Hybridization of chalcone and flavanone to Cinamoyl flavanone.

Herein, we have reported one-pot, economical and eco-friendly syntheses of 6-cinnamoyl flavanones by reacting preformed cinnamoyl chalcones²⁶ with NaOAc in refluxing aqueous ethanol in quantitative yields. The method of synthesis is quite simple as it does not involve any sophisticated chemical or apparatus. The purification of the compounds is either by crystallization or by simple filtration of compounds on a short column of silica gel. The compounds synthesized were screened for their antioxidant and antihyperlipidemic activities.

Results and discussion

Chemistry

The starting chalcones (1–24) were prepared in a straightforward manner by reaction of diacetyl benzenes²⁷ and different aromatic aldehydes as reported earlier by us²⁶. The compounds were identical in all respects to those reported earlier. The reaction of the above chalcones (1–24) separately with sodium acetate in ethanol and water (1:1) at 70–80°C for different time intervals gave the hybrid molecules of 5-aryl-6-cinnamoyl-7-methyl-flavanones (25–48) in almost quantitative yields (Scheme 1 and Table 1).

Table 1.  Synthesis of 5-aryl-6-cinnamoyl-7-methyl-flavanone derivatives (25–48) by cyclization of different cinnamoyl chalcones.

Entry	Ring A	Ring B	Product	Time (h)	Isolated yield (%)	cLogP^a
1	Phenyl	4-chloro phenyl	25	40	94	8.15
2	Phenyl	Phenyl	26	40	92	6.92
3	Phenyl	4-fluoro phenyl	27	41	90	7.04
4	Phenyl	4-bromo phenyl	28	40	93	8.32
5	Phenyl	4-benzloxy phenyl	29	40	94	9.45
6	Phenyl	3-chloro phenyl	30	42	93	8.15
7	Phenyl	3,4-dimethoxy phenyl	31	41	92	6.51
8	Phenyl	1-naphthyl	32	40	90	9.29
9	Phenyl	2-naphthyl	33	41	94	9.29
10	4-bromo phenyl	Phenyl	34	42	89	7.62
11	4-bromo phenyl	4-bromo phenyl	35	43	90	9.02
12	4-bromo phenyl	4-fluoro phenyl	36	43	92	7.74
13	4-bromo phenyl	4-chloro phenyl	37	42	92	8.85
14	4-bromo phenyl	4-benzloxy phenyl	38	41	88	10.15
15	4-bromo phenyl	4-methoxy phenyl	39	40	91	7.41
16	4-Benzloxy phenyl	Phenyl	40	44	90	8.19
17	4-benzloxy phenyl	4-bromo phenyl	41	41	93	9.58
18	4-benzloxy phenyl	4-chloro phenyl	42	41	89	9.41
19	4-Benzloxy phenyl	4-benzloxy phenyl	43	42	92	10.72
20	4-Benzloxy phenyl	4-methoxy phenyl	44	41	91	7.98
21	4-benzloxy phenyl	3,4-dimethoxy phenyl	45	43	93	7.77
22	4-chloro phenyl	2-chloro phenyl	46	42	93	8.79
23	4-chloro phenyl	1-naphthyl	47	40	90	9.90
24	4-chloro phenyl	2-naphthyl	48	41	94	9.90

^acLogP was determined by OSIRIS Property Explorer Programme, available at htpp://www.organic-chemistry.org/prog/peo/.

Scheme 1.  Synthesis of 5-phenyl-6-cinnamoyl-7-methyl-flavanones (25–48).

Structures of these compounds were established on the basis of their spectroscopic data and microanalyses. The IR spectra of all the flavanones exhibited the absorption bands around 1670 and 3060 cm⁻¹ for their carbonyl group and alkene CH stretching vibrations. The ESMS (mass spectra) of the compounds showed [M+H]⁺ peaks corresponding to their molecular formulae. The NMR spectra (¹H and ¹³C) were consistent with the proposed structures.

As a prototype, the detailed NMR spectra of (E)-2-(4-chlorophenyl)-6-(3-(4-chlorophenyl) acryloyl)-7-methyl-5-phenylchroman-4-one (25, Figure 2) has been described herein.

Figure 2.  Structure of the compound no. 25.

In the ¹H NMR spectrum of compound 25, the aromatic protons and one of the olefinic protons of the cinnamoyl moiety, adjacent to aromatic ring were observed as m in the range of δ 7.42–6.95. The other olefinic proton of the cinnamoyl group appeared as a d at δ 6.36 (J = 16.1 Hz). The benzylic proton (H-2) was visible as dd at δ 5.56 with J₁ = 12.8 Hz and J₂ = 3.1 Hz, whereas the two methylene protons (H-3) were observed as dd at two different field strengths at δ 3.07 (J₁ = 16.5 Hz and J₂ = 12.8 Hz), and at δ 2.81 (J₁ = 16.5 Hz and J₂ = 3.1 Hz), respectively. The C-7 methyl was visible as singlet at δ 2.30.

In the ¹³C NMR spectrum, the two carbonyl carbons appeared at δ 197.1 and 190.0, whereas the quaternary aromatic carbon C-9 was visible at δ 162.5 ppm and C-7 at δ 143.9 ppm. The other aromatic quaternary carbons (ArC) were observed at their usual chemical shifts of δ 141.5, 138.6, 137.4, 136.9, 136.3, 135.1, 133.2, 129.7, and 116.9 ppm. The C-2 carbon appeared at δ 78.8 ppm, whereas the other tertiary aromatic carbons (ArCH) appeared at δ 143.2, 129.6, 129.5, 129.4, 129.3, 128.5, 128.2, 128.0, 127.8, and 119.6 ppm. The C-3 carbon was visible at δ 46.1 ppm, whereas the methyl carbon was visible at δ 20.8 ppm. Almost similar patterns were observed in ¹H NMR and ¹³C NMR spectra of other compounds 26–48 of the series.

Biology

Antioxidant activities of 5-aryl-6-cinnamoyl-7-methyl-flavanones

The antioxidant activities of compounds 25–48 were evaluated by generating free radicals (superoxide ions (O₂⁻), hydroxyl radicals (OH·), microsomal lipid peroxidation) in vitro in the presence of 200 µg/mL compounds dissolved in DMSO and compared with the control where no compound was added. Superoxide anions were generated enzymatically²⁸ from xanthine (160 mM) using xanthine oxidase (0.04 U) and nitroblue tetrazolium (320 μM). Hydroxyl radicals (OH·) were generated in a nonenzymatic system comprising deoxyribose (2.8 mM), FeSO₄.7H₂O (2.0 mM), sodium ascorbate (2.0 mM) and H₂O₂ (2.8 mM) in 50 mM KH₂ PO₄ buffer (pH 7.4) to a final volume of 2.5 mL. The test compounds were also studied for their inhibitory action against microsomal lipid peroxidation in vitro by nonenzymatic inducer. The scavenging potential of the compounds for O₂⁻, OH·, and microsomal lipid peroxidation is depicted in Figure 3. Alloprinol, mannitol and α-tocopherol were used as standard scavengers for the superoxide ions (O₂⁻), hydroxyl free radicals (OH·) and microsomal lipid peroxidation, respectively.

Figure 3.  Showing the effect of compounds 25–48 at 200 µg/mL on superoxide ion (n mole formazone formed/min), hydroxyl radicals (n mole MDA formed/h) and lipid peroxidation in microsomes (n mole MDA formed/mg protein).

Alloprinol showed 77% superoxide ions scavenging activity at 200 µg/mL, whereas mannitol showed 44% hydroxyl radical scavenging activity at the same concentration. α-tocopherol showed 52% inhibition of lipid peroxidation at 200 µg/mL concentrations. The compounds of the series showed moderate to significant antioxidant activities. Compounds 25–48 inhibit superoxide ions by 7, 4, 8, 13, 3, 11, 5, 14, 5, 5, 6, 5, 6, 6, 13, 7, 7, 8, 11, 8, 4, 10, 7, and 7%, respectively. They inhibit hydroxyl radicals by 13, 8, 10, 18, 9, 7, 11, 8, 8, 11, 6, 7, 9, 9, 10, 11, 5, 12, 8, 7, 11, 10, 10, and 8%, respectively, whereas inhibition of microsomal lipid peroxidation is 6, 1, 8, 17, 6, 7, 5, 9, 13, 13, 4, 9, 12, 6, 9, 8, 16, 5, 11, 7, 7, 13, 6, and 6%, respectively. The compound 28 having Br group in ring B was found to be the most active compound of the series. It showed significant inhibition of superoxide anions (24%), hydroxyl radicals (19%) and microsomal lipid peroxidation (21%), respectively. The properties of these cinnamoyl flavanones as antioxidant and free radical scavenger appear to be due to extended conjugation in the molecule which facilitates the electron transfer and the resonance stabilization through keto-enol tautomerism of propenone moiety. The latter has the ability to delocalize unpaired electrons of free radicals^29–36. No definite structure activity relationship could be established in the series for antioxidant activity.

Effect of 5-aryl-6-cinnamoyl-7-methyl-flavanones on hyperlipidemia

The total cholesterol (TC) of control groups was estimated to be 85.40 ± 4.00 mg/dl (Figure 4). Administration of triton WR-1339 in rats induced marked hyperlipidemia as evidenced by 3.87-fold increase in the plasma levels of TC (329.04 ± 15.00). The standard drug gemfibrozil decreased the TC level by 35% as compared to triton only group. The compounds 25–48 exhibited their TC lowering activity in 2–25% range. Five compounds of the series, compounds 28, 29, 30, 32, and 48, were found to have significant TC inhibitory activities as they decreased the TC level by 22, 25, 21, 21 and 25%, respectively.

Figure 4.  Total cholesterol lowering activity of compounds 25–48 and the standard drug gemfibrozil.

Treatment of rats with triton WR-1339 increased their plasma phospholipids (PL) by 3.75-folds (Figure 5). The animal group treated with triton only were compared with the animal group treated with triton and compounds both. The compounds 25–28 showed their PL-lowering activities in a range of 4–26%. Five compounds of the series 28, 29, 30, 32, and 48 decreased the PL level by 21, 26, 24, 20 and 24%, respectively. Thus compound 29 with 26% PL-lowering activity was the most active compound of the series as compared to the standard drug gemfibrozil, which displayed 33% PL-lowering activity.

Figure 5.  Phospholipid lowering activity of compounds 25–48 and the standard drug gemfibrozil.

Treatment of rats with triton WR-1339 increased their triglyceride (Tg) level by 3.92-folds (Figure 6). The Tg levels in the two animal groups, one group treated with triton only and the other group with triton and compounds both were compared. The compounds showed their Tg lowering activities in a range of 4–24%. Five compounds 28, 29, 30, 32, and 48 of the series were found to decrease the Tg level by 19, 25, 23, 18 and 24%, respectively. Thus compound 29 with 25% Tg lowering was the most active compound of the series as compared to the drug gemfibrozil with 32% Tg lowering activity.

Figure 6.  Triglyceride lowering activity of compounds 25–48 and the standard drug gemfibrozil.

Administration of triton in rats elevated their protein levels by 2.08-fold (Figure 7). Triton WR-1339 acts as surfactant, suppresses the action of lipase and blocks the uptake of lipoproteins from the circulation of extra hepatic tissues resulting in an increased level of circulatory lipids^37,38. Treatment of hyperlipidemic rats with compounds 25–48 reversed the plasma level of protein with varying extents. Compounds 28, 29, 30, 46 and 48 exhibited 16, 23, 22, 22 and 20% protein lowering activity, respectively, whereas other compounds exhibited mild lowering of protein levels as compared to triton. These data were compared with gemfibrozil, which showed a decrease of 36% in protein levels.

Figure 7.  Protein lowering activity of compounds 25–48 and the standard drug gemfibrozil.

With this sizable number of compounds, although no definite SAR could be established on protein lowering activity, yet a closure look into the structure activity relationship revealed that in general, compounds (32) B ring as naphthyl substituent are more active than those with phenyl ring substituent. The effect of halo substituents in the aryl ring B, in general, results in the increased activity with Br > F > Cl trend with the exception of compound 35. Further, positional substitution of halo substituents follows the pattern m > p > o. It is also observed that substitution of phenyl ring of the cinnamoyl group with 4-OCH₂Ph results in better activity as compared to 4-OCH₃ or halogen. In general, the compounds having phenyl or chlorophenyl as ring A are more active than compounds with benzyloxy or bromophenyl substituents.

Conclusion

In conclusions, a series of novel 5-aryl-6-cinnamoyl-7-methyl-flavanones has been synthesized from (2E,2′E)-1,1′-(3-hydroxy-5-methylbiphenyl-2,6-diyl)bis(3-phenylprop-2-en-1-one) derivatives in very good yields. The compounds were evaluated for their antidyslipidemic and antioxidant activities. A number of compounds showed significant to moderate activities. Further work with these molecules is underway to prepare more potent compounds having drug like properties.

Experimental

Chemistry

Commercially available reagent grade chemicals were used as received. All reactions were followed by TLC on E. Merck Kieselgel 60 F₂₅₄, with detection by UV light, spraying a 20% KMnO₄ aq solution. Column chromatography was performed on silica gel (100–200 mesh E. Merck). IR spectra were recorded as thin films or in KBr solution with a Perkin-Elmer Spectrum RX-1 (4000–450 cm⁻¹) spectrophotometer. ¹H and ¹³C NMR spectra were recorded on a Brucker DRX-200 in CDCl₃ and CDCl₃+CCl₄. Chemical shift values are reported in ppm relative to TMS (tetramethylsilane) as internal reference, unless otherwise stated; s (singlet), d (doublet), dd (doublet of doublet), m (multiplet); J in hertz. ESI mass spectra were performed using Quattro II (Micromass). Elemental analyses were performed on a Perkin-Elmer 2400 II elemental analyzer.

General procedure for the synthesis of cinnamoyl flavanones

To a stirring solution of (2E,2′E)-1,1′-(3-hydroxy-5-methylbiphenyl-2,6-diyl)-bis(3-pheylprop-2-ene-1-ones derivatives (1 equiv.) in minimum amount of a mixture of EtOH: H₂O (1:1) and NaOAc (4 equiv.) was added. The reaction mixture was heated to reflux till the disappearance of the starting materials. After completion of reaction (TLC), the reaction mixture was allowed to cool to room temperature. The mixture was then diluted with H₂O and extracted with Et₂O. The combined organic phases were washed with brine, dried over anhydrous sodium sulphate, and concentrated under reduced pressure. The crude product was purified either by crystallization or by filtration through a short column of SiO₂ (60–120 mesh) using appropriate eluent to give the desired flavanone.

(E)-2-(4-chlorophenyl)-6-[3-(4-chlorophenyl)acryloyl]-7-methyl-5-phenylchroman-4-one (25)

It was obtained as light yellow solid, mp 190–192°C, in 94% yield; R_f = 0.6 (8:2 hexane:ethylacetate); IR (KBr): υ_max in cm⁻¹ 3360, 3060, 1691, 1670, 1597, 1489, 1425, 1319, 1159, 1088, 818, 700; ¹H NMR (200 MHz, CDCl₃+CCl₄): δ = 7.42 (s, 4H, 3 × ArH & = CH), 7.31–7.14 (m, 8H, ArH), 7.06–6.95 (m, 3H, ArH), 6.36 (d, J = 16.1 Hz, 1H, = CH), 5.56 (dd, J₁ = 12.8 Hz, J₂ = 3.1 Hz, 1H, CH), 3.07 (dd, J₁ = 16.5 Hz, J₂ = 12.8 Hz, 1H, H_a, CH₂), 2.81 (dd, J₁ = 16.5 Hz, J₂ = 3.1 Hz, 1H, H_b, CH₂), 2.30 (s, 3H, CH₃); ¹³C NMR (50 MHz, CDCl₃+CCl₄): δ = 197.1, 190.0 (2 × CO), 162.5, 143.9, 141.5, 138.6, 137.4, 136.9, 135.1, 133.2, 129.7, 129.6, 129.5, 129.4, 129.3, 128.5, 128.2, 128.0, 127.8, 119.6, 116.9, 78.8, 46.1, 20.8; MS (ESI⁺): m/z: 513[M+H]⁺. Elemental analysis for C₃₁H₂₂O₃Cl₂: Calcd. C, 72.52; H, 4.32. Found: C, 72.50; H, 4.28.

6-cinnamoyl-7-methyl-2,5-diphenylchroman-4-one (26)

It was obtained as light yellow solid, mp 148–150°C, in 93% yield; R_f = 0.6 (8:2 hexane:ethylacetate); IR (KBr): υ_max in cm⁻¹ 3410, 3021, 2359, 1636, 1596, 1217, 769; ¹H NMR (200 MHz, CDCl₃+CCl₄): δ = 7.47–7.41 (m, 5H, 4 × ArH & = CH), 7.32–7.24 (m, 9H, ArH), 7.11–7.02 (m, 3H, ArH), 6.44 (d, J = 16.1 Hz, 1H, = CH), 5.59 (d, J = 12.6 Hz, 1H, CH), 3.13 (dd, J₁ = 16.3 Hz, J₂ = 13.3 Hz, 1H, H_a, CH₂), 2.82 (d, J = 16.3 Hz, 1H, H_b, CH₂), 2.31 (s, 3H, CH₃); ¹³C NMR (50 MHz, CDCl₃+CCl₄): δ = 197.6, 190.5 (2 × CO), 162.7, 145.1, 143.6, 141.5, 139.0, 138.7, 136.2, 134.8, 130.8, 129.8, 128.6, 128.4, 128.1, 127.8, 126.4, 119.6, 117.0, 79.6, 46.3, 20.8; MS (ESI⁺): m/z: 445[M+H]⁺. Elemental analysis for C₃₁H₂₄O₃: Calcd. C, 83.76; H, 5.44, Found: C, 83.69; H, 5.40.

(E)-2-(4-fluorophenyl)-6-[3-(4-fluorophenyl)acryloyl]-7-methyl-5-phenylchroman-4-one (27)

It was obtained as yellow solid, mp 152–154°C, in 93% yield; R_f = 0.6 (8:2 hexane:ethylacetate); IR (KBr): υ_max in cm⁻¹ 3862, 3429, 3021, 2359, 1639, 1515, 1216, 1043, 766, 671; ¹H NMR (200 MHz, CDCl₃+CCl₄): δ = 7.49–7.00 (m, 15H, 14 ArH & = CH), 6.34 (d, J = 16.1 Hz, 1H, = CH), 5.55 (d, J = 12.6 Hz, 1H, CH), 3.09 (dd, J₁ = 16.2 Hz, J₂ = 13.3 Hz, 1H, H_a, CH₂), 2.80 (d, J = 16.3 Hz, 1H, H_b, CH₂), 2.30 (s, 3H, CH₃); ¹³C NMR (50 MHz, CDCl₃+CCl₄): δ = 197.3, 190.2 (2 × CO), 162.6, 143.8, 143.6, 141.5, 138.6, 136.3, 134.8, 134.7, 131.0 130.9, 130.5, 130.3, 129.7, 129.3, 128.4, 128.2, 128.1, 128.0, 127.9, 119.6, 116.9, 116.6, 116.4, 116.2, 116.0, 78.9, 46.2, 20.8; MS (ESI⁺): m/z: 481[M+H]⁺. Elemental analysis for C₃₁H₂₂O₃F₂: Calcd. C, 77.49; H, 4.61. Found: C, 77.38; H, 4.57.

(E)-2-(4-bromophenyl)-6-[3-(4-bromophenyl)acryloyl]-7-methyl-5-phenylchroman-4-one (28)

It was obtained as light yellow solid, mp 188–190°C, in 93% yield; R_f = 0.6 (8:2 hexane:ethylacetate); IR (KBr): υ_max in cm⁻¹ 3779, 3459, 2366, 1670, 1596, 1318, 1159, 1008, 815; ¹H NMR (200 MHz, CDCl₃+CCl₄): δ = 7.59–6.93 (m, 15H, 14 ArH & = CH), 6.37 (d, J = 16.0 Hz, 1H, = CH), 5.55 (dd, J₁ = 12.7 Hz, J₂ = 2.8 Hz, 1H, CH), 3.06 (dd, J₁ = 16.5 Hz, J₂ = 13.1 Hz, 1H, H_a, CH₂), 2.81 (dd, J₁ = 16.5 Hz, J₂ = 2.9 Hz, 1H, H_b, CH₂), 2.30 (s, 3H, CH₃); ¹³C NMR (50 MHz, CDCl₃+CCl₄): δ = 197.2, 189.9 (2 × CO), 162.5, 143.9, 143.3, 138.5, 137.9, 133.6, 132.5, 132.4, 129.8, 129.7, 129.3, 128.6, 128.2, 128.1, 125.3, 123.2, 119.6, 116.9, 78.8, 46.1, 20.8; MS (ESI⁺): m/z: 601[M+H]⁺. Elemental analysis for C₃₁H₂₂O₃Br₂: Calcd. C, 61.82; H, 3.68. Found: C, 61.81; H, 3.65.

(E)-2-[4-(benzyloxy)phenyl]-6-[3-{4-(benzyloxy)phenyl}acryloyl]-7-methyl-5-phenylchroman-4-one (29)

It was obtained as light yellow solid, mp 163–165°C, in 94% yield; R_f = 0.4 (8:2 hexane:ethylacetate); IR (KBr): υ_max in cm⁻¹ 3449, 3055, 2368, 1692, 1597, 1510, 1240, 1170, 1002, 743, 697; ¹H NMR (200 MHz, CDCl₃+CCl₄): δ = 7.41–7.23 (m, 18H, 17 ArH & = CH), 7.04–6.88 (m, 7H, ArH), 6.33 (d, J = 16.4 Hz, 1H, = CH), 5.51 (d, J = 12.5 Hz, 1H, CH), 5.10 (s, 2H, OCH₂), 5.07 (s, 2H, OCH₂), 3.13 (dd, J₁ = 15.5 Hz, J₂ = 13.8 Hz, 1H, H_a, CH₂), 2.78 (d, J = 16.1 Hz, 1H, H_b, CH₂), 2.29 (s, 3H, CH₃); ¹³C NMR (50 MHz, CDCl₃+CCl₄): δ = 197.3, 190.2 (2 × CO), 162.6, 143.8, 143.6, 141.4, 138.6, 136.3, 134.8, 134.7, 131.0, 130.9, 130.5, 130.3, 129.7, 129.3, 128.4, 128.2, 128.1, 127.9, 119.6, 116.9, 116.6, 116.4, 116.2, 116.0, 78.9, 70.4, 46.2, 20.8; MS (ESI⁺): m/z: 657[M+H]⁺. Elemental analysis for C₄₅H₃₆O₅: Calcd. C, 82.29; H, 5.52. Found: C, 82.10; H, 5.50.

(E)-2-(3-chlorophenyl)-6-[3-(3-chlorophenyl)acryloyl]-7-methyl-5-phenylchroman-4-one (30)

It was obtained as light yellow solid, mp 190–192°C, in 94% yield; R_f = 0.6 (8:2 hexane:eyhylacetate); IR (KBr): υ_max in cm⁻¹ 3434, 3020, 2365, 1690, 1595, 1218, 768; ¹H NMR (200 MHz, CDCl₃+CCl₄): δ = 7.51 (s, 1H, ArH), 7.39–7.15 (m, 11H, 10 ArH & = CH), 7.07–7.02 (m, 2H, ArH), 6.94 (s, 1H, ArH), 6.39 (d, J = 16.0 Hz, 1H, = CH), 5.56 (dd, J₁ = 12.9 Hz, J₂ = 3.1 Hz, 1H, CH), 3.08 (dd, J₁ = 16.5 Hz, J₂ = 12.9 Hz, 1H, H_a, CH₂), 2.83 (dd, J₁ = 16.5 Hz, J₂ = 3.2 Hz, 1H, H_b, CH₂), 2.31 (s, 3H, CH₃); ¹³C NMR (50 MHz, CDCl₃+CCl₄): δ = 197.1, 189.8 (2 × CO), 162.5, 143.9, 143.0, 141.6, 141.0, 138.5, 136.6, 136.2, 135.3, 130.6, 130.5, 130.4, 129.8, 129.4, 129.3, 128.4, 128.2, 128.0, 126.7, 126.5, 124.4, 119.6, 116.9, 78.8, 46.2, 20.8; MS (ESI⁺): m/z: 513[M+H]⁺. Elemental analysis for C₃₁H₂₂O₃Cl₂: Calcd. C, 72.52; H, 4.32. Found: C, 72.50; H, 4.28.

(E)-2-(3,4-dimethoxyphenyl)-6-[3-(3,4-dimethoxyphenyl)acryloyl]-7-methyl-5-phenylchroman-4-one (31)

It was obtained as light yellow solid, mp 90–92°C, in 92% yield; R_f = 0.4 (7:3 hexane:ethylacetate); IR (KBr): υ_max in cm⁻¹ 3445, 2960, 2370, 1691, 1637, 1596, 1514, 1428, 1261, 1024, 859, 555; ¹H NMR (200 MHz, CDCl₃+CCl₄): δ = 7.26–7.13 (m, 4H, 3 ArH & = CH), 7.04–6.75 (m, 9H, ArH), 6.31 (d, J = 16.0 Hz, 1H, = CH), 5.50 (dd, J₁ = 2.6 Hz and J₂ = 12.9 Hz, 1H, CH), 3.92–3.84 (m, 12H, 4 × OCH₃), 3.12 (dd, J₁ = 13.1 Hz and J₂ = 16.4 Hz, 1H, H_a, CH₂), 2.78 (dd, J₁ = 16.5 Hz, J₂ = 2.8 Hz, 1H, H_b, CH₂), 2.29 (s, 3H, CH₃); ¹³C NMR (50 MHz, CDCl₃+CCl₄): δ = 197.6, 190.7 (2 × CO), 162.6, 151.9, 149.9, 149.8, 149.6, 145.6, 143.6, 141.3, 138.8, 136.3, 131.4, 129.7, 129.3, 128.0, 127.8, 127.7, 126.6, 123.4, 119.6, 119.2, 117.1, 111.6, 111.4, 110.1, 109.9, 79.5, 56.3, 56.2, 56.1, 46.2, 20.8; MS (ESI⁺): m/z: 565[M+H]⁺. Elemental analysis for C₃₅H₃₂O₇: Calcd. C, 74.45; H, 5.71. Found: C, 74.39; H, 5.67.

(E)-7-Methyl-2-(naphthalen-1-yl)-6-[3-(naphthalen-1-yl)acryloyl]-5-phenylchroman-4-one (32)

It was obtained as light yellow solid, mp 180–181°C, in 92% yield; R_f = 0.4 (7:3 hexane:ethylacetate); IR (KBr): υ_max in cm⁻¹ 3428, 3056, 2367, 1695, 1635, 1596, 1342, 1178, 980, 775, 698; ¹H NMR (200 MHz, CDCl₃+CCl₄): δ = 8.10 (d, J = 7.5 Hz, 1H, ArH), 7.99–7.77 (m, 7H, 6 ArH & = CH), 7.55–7.09 (m, 12H, ArH), 6.54 (d, J = 15.8 Hz, 1H, = CH), 6.35 (d, J = 12.7 Hz, 1H, CH), 3.31 (dd, J₁ = 16.4 Hz, J₂ = 13.3 Hz, 1H, H_a, CH₂), 3.05 (d, J = 16.2 Hz, 1H, H_b, CH₂), 2.40 (s, 3H, CH₃); ¹³C NMR (50 MHz, CDCl₃+CCl₄): δ = 197.5, 190.8 (2 × CO), 163.0, 143.8, 141.8, 141.6, 138.8, 136.6, 134.4, 134.3, 134.0, 132.3, 131.8, 131.0, 130.6, 130.1, 129.8, 129.6, 129.5, 129.1, 128.3, 128.0, 127.2, 127.1, 126.6, 126.3, 125.7, 124.1, 123.7, 123.2, 119.8, 117.1, 78.0, 45.6, 20.9; MS (ESI⁺): m/z: 545[M+H]⁺. Elemental analysis for C₃₉H₂₈O₃: Calcd. C, 86.01; H, 5.18. Found: C, 85.91; H, 5.15.

(E)-7-methyl-2-(naphthalen-2-yl)-6-[3-(naphthalen-2-yl)acryloyl]-5-phenylchroman-4-one (33)

It was obtained as light yellow solid, mp 184–185°C, in 94% yield; R_f = 0.4 (8:2 hexane:ethylacetate); IR (KBr): υ_max in cm⁻¹ 3465, 3050, 2369, 1690, 1597, 1429, 1263, 1187, 984, 747, 473; ¹H NMR (200 MHz, CDCl₃+CCl₄): δ = 7.95–7.73 (m, 8H, 7 ArH & = CH), 7.62–7.40 (m, 7H, ArH), 7.27–7.19 (m, 4H, ArH), 7.12–7.07 (m, 2H, ArH), 6.55 (d, J = 16.0 Hz, 1H, = CH), 5.77 (dd, J₁ = 13.6 Hz, J₂ = 2.9 Hz, 1H, CH), 3.24 (dd, J₁ = 16.5 Hz, J₂ = 13.0 Hz, 1H, H_a, CH₂), 2.93 (dd, J₁ = 16.5 Hz, J₂ = 3.0 Hz, 1H, H_b, CH₂), 2.35 (s, 3H, CH₃); ¹³C NMR (50 MHz, CDCl₃+CCl₄): δ = 197.7, 190.5 (2 × CO), 162.7, 145.3, 143.8, 141.5, 138.8, 136.3, 134.7, 133.8, 133.6, 132.3, 130.7, 129.8, 129.4, 129.2, 129.0, 128.9, 128.5, 128.2, 127.9, 127.8, 127.7, 127.1, 126.9, 125.7, 123.9, 123.8, 119.7, 117.1, 79.7, 46.3, 20.8; MS (ESI⁺): m/z: 545[M+H]⁺. Elemental analysis for C₃₉H₂₈O₃: Calcd. C, 86.01; H, 5.18. Found: C, 85.89; H, 5.15.

5-(4-bromophenyl)-6-cinnamoyl-7-methyl-2-phenylchroman-4-one (34)

It was obtained as light yellow solid, mp 168–170°C in 92% yield; R_f = 0.6 (8:2 hexane:ethylacetate); IR (KBr): υ_max in cm⁻¹ 3434, 3022, 2364, 1639, 1216, 767, 671; ¹H NMR (200 MHz, CDCl₃+CCl₄): δ = 7.46–7.26 (m, 12H, 11 ArH & = CH), 7.03–6.91 (m, 4H, ArH), 6.49 (d, J = 16.1 Hz, 1H, = CH), 5.58 (d, J = 12.1 Hz, 1H, CH), 3.13 (dd, J₁ = 16.3 Hz, J₂ = 13.7 Hz, 1H, H_a, CH₂), 2.82 (d, J = 16.1 Hz, 1H, H_b, CH₂), 2.30 (s, 3H, CH₃); ¹³C NMR (50 MHz, CDCl₃+CCl₄): δ = 197.7, 190.6 (2 × CO), 162.7, 146.1, 143.7, 140.0, 138.8, 137.6, 136.0, 134.6, 131.4, 131.3, 131.1, 130.9, 129.3, 129.2, 128.7, 128.6, 126.4, 122.1, 119.9, 116.9, 79.6, 46.2, 20.7; MS (ESI⁺): m/z: 523[M+H]⁺. Elemental analysis for C₃₁H₂₃BrO₃: Calcd. C, 71.13; H, 4.43. Found: C, 71.06; H, 4.40.

(E)-2,5-bis(4-bromophenyl)-6-[3-(4-bromophenyl)acryloyl]-7-methylchroman-4-one (35)

It was obtained as yellow solid, mp 221–223°C in 94% yield; R_f = 0.5 (8:2 hexane:ethylacetate); IR (KBr): υ_max in cm⁻¹ 3426, 3021, 2363, 1633, 1584, 1216, 761, 671; ¹H NMR (200 MHz, CDCl₃+DMSO): δ = 7.59–7.30 (m, 10H, 9 ArH & = CH), 7.05–6.89 (m, 4H, ArH), 6.54 (d, J = 16.0 Hz, 1H, = CH), 5.67 (d, J = 11.9 Hz, 1H, CH), 3.08 (dd, J₁ = 16.4 Hz, J₂ = 13.0 Hz, 1H, H_a, CH₂), 2.79 (d, J = 16.3 Hz, 1H, H_b, CH₂), 2.23 (s, 3H, CH₃); ¹³C NMR (50 MHz, CDCl₃+CCl₄): δ = 197.4, 190.2 (2 × CO), 162.5, 144.9, 143.3, 139.6, 138.6, 138.4, 135.9, 133.8, 132.6, 132.3, 132.1, 131.5, 130.9, 130.7, 129.1, 128.9, 125.3, 122.8, 121.5, 120.1, 117.2, 78.7, 45.9, 20.7; MS (ESI⁺): m/z: 679[M+H]⁺. Elemental analysis for C₃₁H₂₁Br₃O₃: Calcd. C, 54.66; H, 3.11. Found: C, 54.50; H, 3.09.

(E)-5-(4-bromophenyl)-2-(4-fluorophenyl)-6-[3-(4-fluorophenyl)acryloyl]-7-methylchroman-4-one (36)

It was obtained as light yellow solid, mp 168–170°C in 92% yield; R_f = 0.5 (8:2 hexane:ethylacetate); IR (KBr): υ_max in cm⁻¹ 3426, 2927, 2365, 1636, 1595, 1509, 1230, 1160, 836, 755, 514; ¹H NMR (200 MHz, CDCl₃+CCl₄): δ = 7.49–7.26 (m, 6H, 5 ArH & = CH), 7.18–6.80 (m, 8H, ArH), 6.38 (d, J = 16.1 Hz, 1H, = CH), 5.55 (dd, J₁ = 13.0 Hz, J₂ = 2.9 Hz, 1H, CH), 3.09 (dd, J₁ = 16.5 Hz, J₂ = 13.0 Hz, 1H, H_a, CH₂), 2.80 (dd, J₁ = 16.5 Hz, J₂ = 3.0 Hz, 1H, H_b, CH₂), 2.29 (s, 3H, CH₃); ¹³C NMR (50 MHz, CDCl₃+CCl₄): δ = 197.1, 190.1 (2 × CO), 162.5, 144.3, 143.8, 140.0, 137.5, 136.1, 134.6, 131.4, 131.3, 131.1, 130.9, 130.7, 130.6, 130.4, 128.4, 128.2, 119.9, 116.8, 116.4, 116.3, 116.0, 78.9, 46.1, 20.7; MS (ESI⁺): m/z: 559[M+H]⁺. Elemental analysis for C₃₁H₂₁BrF₂O₃: Calcd. C, 66.56; H, 3.78. Found: C, 66.50; H, 3.71.

(E)-5-(4-bromophenyl)-2-(4-chlorophenyl)-6-[3-(4-chlorophenyl)acryloyl]-7-methylchroman-4-one (37)

It was obtained as light yellow solid, mp 174–176°C in 94% yield; R_f = 0.5 (8:2 hexane:ethylacetate); IR (KBr): υ_max in cm⁻¹ 3458, 3020, 2365, 1691, 1594, 1216, 1089, 765, 501; ¹H NMR (200 MHz, CDCl₃+CCl₄): δ = 7.41–7.23 (m, 10H, 9 ArH & = CH), 7.01–6.88 (m, 4H, ArH), 6.41 (d, J = 16.1 Hz, 1H, = CH), 5.55 (d, J = 11.0 Hz, 1H, CH), 3.07 (dd, J₁ = 16.3 Hz, J₂ = 12.9 Hz, 1H, H_a, CH₂), 2.80 (d, J = 15.7 Hz, 1H, H_b, CH₂), 2.29 (s, 3H, CH₃); ¹³C NMR (50 MHz, CDCl₃+CCl₄): δ = 197.1, 190.0 (2 × CO), 162.5, 144.1, 143.8, 140.1, 137.4, 137.2, 136.1, 135.2, 133.0, 131.3, 131.1, 131.0, 129.7, 129.6, 129.5, 128.7, 127.7, 122.3, 119.9, 116.8, 78.8, 46.0, 20.7; MS (ESI⁺): m/z: 591[M+H]⁺. Elemental analysis for C₃₁H₂₁BrCl₂O₃: Calcd. C, 62.86; H, 3.57. Found: C, 62.80; H, 3.43.

(E)-2-(4-(benzyloxy)phenyl)-6-[3-{4-(benzyloxy)phenyl}acryloyl]-5-(4-bromophenyl)-7-methylchroman-4-one (38)

It was obtained as light yellow solid, mp 192–195°C in 92% yield; R_f = 0.5 (7:3 hexane:ethylacetate); IR (KBr): υ_max in cm⁻¹ 3752, 3454, 3021, 2364, 1563, 1216, 1017, 761; ¹H NMR (200 MHz, CDCl₃+CCl₄): δ = 7.43–7.26 (m, 16H, 15 ArH & = CH), 7.06–6.92 (m, 8H, ArH), 6.42 (d, J = 16.1 Hz, 1H, = CH), 5.53 (dd, J₁ = 13.1 Hz, J₂ = 2.6 Hz, 1H, CH), 5.11–5.09 (m, 4H, 2 × OCH₂), 3.15 (dd, J₁ = 16.6 Hz, J₂ = 13.2 Hz, 1H, H_a, CH₂), 2.79 (dd, J₁ = 16.6 Hz, J₂ = 2.8 Hz, 1H, H_b, CH₂), 2.27 (s, 3H, CH₃); ¹³C NMR (50 MHz, CDCl₃+CCl₄): δ = 198.2, 190.4 (2 × CO), 162.7, 161.5, 159.6, 146.6, 143.7, 139.8, 137.8, 137.1, 136.7, 136.0, 131.3, 131.2, 131.1, 130.8, 130.6, 129.1, 128.6, 128.5, 128.1, 127.8, 127.4, 126.6, 122.0, 119.9, 116.9, 115.7, 115.6, 79.4, 70.5, 45.9, 20.7; MS (ESI⁺): m/z: 735[M+H]⁺. Elemental analysis for C₄₅H₃₅O₅Br: Calcd. C, 73.47; H, 4.80. Found: C, 73.41; H, 4.75.

(E)-5-(4-bromophenyl)-2-(4-methoxyphenyl)-6-[3-(4-methoxyphenyl)acryloyl]-7-methylchroman-4-one (39)

It was obtained as light yellow solid, mp 178–180°C in 91% yield; R_f = 0.4 (7:3 hexane:ethylacetate); IR (KBr): υ_max in cm⁻¹ 3756, 3019, 2364, 1598, 1216, 1168, 1030, 763; ¹H NMR (200 MHz, CDCl₃+CCl₄): δ = 7.41–7.26 (m, 6H, 5 ArH & = CH), 7.04–6.83 (m, 8H, ArH), 6.38 (d, J = 16.1 Hz, 1H, = CH), 5.52 (dd, J₁ = 13.1 Hz, J₂ = 2.7 Hz, 1H, CH), 3.84–3.80 (m, 6H, 2 × OCH₃), 3.13 (dd, J₁ = 16.5 Hz, J₂ = 13.2 Hz, 1H, H_a, CH₂), 2.78 (dd, J₁ = 16.5 Hz, J₂ = 2.8 Hz, 1H, H_b, CH₂), 2.28 (s, 3H, CH₃); ¹³C NMR (50 MHz, CDCl₃+CCl₄): δ = 197.7, 190.9 (2 × CO), 162.7, 162.3, 160.4, 146.2, 143.6, 139.9, 137.8, 136.1, 131.4, 131.2, 131.0, 130.8, 130.5, 128.0, 127.2, 126.5, 122.0, 119.8, 116.8, 114.8, 114.6, 79.3, 55.7, 55.6, 46.0, 20.7; MS (ESI⁺): m/z: 583[M+H]⁺. Elemental analysis for C₃₃H₂₇O₅Br: Calcd. C, 67.93; H, 4.66. Found: C, 67.80; H, 4.55.

5-(4-(benzyloxy)phenyl)-6-cinnamoyl-7-methyl-2-phenylchroman-4-one (40)

It was obtained as light yellow solid, mp 168–169°C in 90% yield; R_f = 0.4 (7:3 hexane:ethylacetate); IR (KBr): υ_max in cm⁻¹ 3779, 3380, 3021, 2359, 1596, 1216, 762, 671; ¹H NMR (200 MHz, CDCl₃+CCl₄): δ = 7.47–7.26 (m, 15H, 14 ArH & = CH), 7.14–7.11 (m, 2H, ArH), 7.03–6.89 (m, 2H, ArH), 6.88–6.84 (m, 2H, ArH), 6.44 (d, J = 16.1 Hz, 1H, = CH), 5.59 (dd, J₁ = 13.1 Hz, J₂ = 3.0 Hz, 1H, CH), 4.95 (s, 2H, OCH₂), 3.13 (dd, J₁ = 16.5 Hz, J₂ = 13.1 Hz, 1H, H_a, CH₂), 2.84 (dd, J₁ = 16.5 Hz, J₂ = 3.0 Hz, 1H, H_b, CH₂), 2.31 (s, 3H, CH₃); ¹³C NMR (50 MHz, CDCl₃+CCl₄): δ = 197.8, 190.6 (2 × CO), 162.8, 158.7, 144.7, 143.7, 141.3, 139.0, 137.3, 136.5, 134.9, 131.1, 130.8, 130.7, 129.2, 128.8, 128.6, 128.4, 128.2, 127.8, 126.4, 119.5, 114.3, 79.5, 70.2, 46.4, 20.8; MS (ESI⁺): m/z: 551[M+H]⁺. Elemental analysis for C₃₈H₃₀O₄: Calcd. C, 82.89; H, 5.49. Found: C, 82.70; H, 5.45.

(E)-5-(4-(benzyloxy)phenyl)-2-(4-bromophenyl)-6-[3-(4-bromophenyl)acryloyl]-7-methylchroman-4-one (41)

It was obtained as light yellow solid, mp 170–171°C in 93% yield; R_f = 0.4 (7:3 hexane:ethylacetate); IR (KBr): υ_max in cm⁻¹ 3762, 3427, 3022, 2368, 1635, 1217, 767, 671; ¹H NMR (200 MHz, CDCl₃+CCl₄): δ = 7.59–7.26 (m, 11H, 10 ArH & = CH), 7.17–7.07 (m, 3H, ArH), 7.01–6.83 (m, 5H, ArH), 6.37 (d, J = 16.0 Hz, 1H, = CH), 5.54 (d, J = 12.6 Hz, 1H, CH), 4.95 (m, 2H, OCH₂), 3.06 (dd, J₁ = 16.1 Hz, J₂ = 12.9 Hz, 1H, H_a, CH₂), 2.81 (d, J = 16.4 Hz, 1H, H_b, CH₂), 2.30 (s, 3H, CH₃); ¹³C NMR (50 MHz, CDCl₃+CCl₄): δ = 197.8, 191.0 (2 × CO), 162.7, 158.6, 151.9, 149.9, 149.6, 145.3, 143.7, 137.3, 131.4, 130.6, 128.8, 128.2, 127.8, 126.6, 123.4, 119.2, 109.9, 70.5, 20.9; MS (ESI⁺): m/z: 707[M+H]⁺. Elemental analysis for C₃₈H₂₈O₄Br₂: Calcd. C, 64.42; H, 3.98. Found: C, 64.39; H, 3.88.

(E)-5-(4-(benzyloxy)phenyl)-2-(4-chlorophenyl)-6-[3-(4-chlorophenyl)acryloyl]-7-methylchroman-4-one (42)

It was obtained as light yellow solid, mp 164–165°C in 93% yield; R_f = 0.4 (7:3 hexane:ethylacetate); IR (KBr): υ_max in cm⁻¹ 3420, 2368, 1687, 1598, 1511, 1244, 1173, 1029, 838, 760, 522; ¹H NMR (200 MHz, CDCl₃+CCl₄): δ = 7.42–7.24 (m, 13H, 12 ArH & = CH), 7.20–6.95 (m, 4H, ArH), 6.86–6.83 (m, 2H, ArH), 6.36 (d, J = 16.0 Hz, 1H, = CH), 5.56 (dd, J₁ = 12.7 Hz, J₂ = 3.2 Hz, 1H, CH), 4.95 (s, 2H, OCH₂), 3.07 (dd, J₁ = 16.5 Hz, J₂ = 12.7 Hz, 1H, H_a, CH₂), 2.82 (dd, J₁ = 16.5 Hz, J₂ = 3.2 Hz, 1H, H_b, CH₂), 2.30 (s, 3H, CH₃); ¹³C NMR (50 MHz, CDCl₃+CCl₄): δ = 197.1, 190.0 (2 × CO), 162.6, 158.8, 143.9, 142.6, 141.4, 137.4, 137.2, 136.8, 136.6, 135.1, 133.4, 130.9, 129.6, 129.5, 129.4, 128.8, 128.6, 128.2, 127.7, 119.5, 117.0, 78.7, 70.2, 46.2, 20.8; MS (ESI⁺): m/z: 619[M+H]⁺. Elemental analysis for C₃₈H₂₈O₄Cl₂: Calcd. C, 73.67; H, 4.56. Found: C, 73.60; H, 4.52.

(E)-2,5-bis(4-(benzyloxy)phenyl)-6-[3-{4-(benzyloxy)phenyl}acryloyl]-7-methylchroman-4-one (43)

It was obtained as light yellow solid, mp 64–65°C in 92% yield; R_f = 0.4 (7:3 hexane:ethylacetate); IR (KBr): υ_max in cm⁻ 3781, 3324, 3036, 2362, 1602, 1505, 1247, 1016, 829, 731, 607; ¹H NMR (200 MHz, CDCl₃+CCl₄): 7.43–7.26 (m, 19H, 18 ArH & = CH), 7.19–6.30 (m, 10H, ArH), 6.38 (d, J = 16.0 Hz, 1H, = CH), 5.53 (dd, J₁ = 13.0 Hz, J₂ = 2.4 Hz, 1H, CH), 5.11–4.96 (m, 6H, 3 × OCH₂), 3.15 (dd, J₁ = 16.5 Hz, J₂ = 13.4 Hz, 1H, H_a, CH₂), 2.80 (dd, J₁ = 16.5 Hz, J₂ = 2.7 Hz, 1H, H_b, CH₂), 2.28 (s, 3H, CH₃); ¹³C NMR (50 MHz, CDCl₃+CCl₄): δ = 198.5, 191.4 (2 × CO), 162.8, 161.2, 159.6, 158.6, 145.4, 143.7, 137.4, 137.1, 136.7, 131.4, 131.2, 131.0, 130.5, 129.1, 128.9, 128.6, 128.5, 128.3, 128.1, 128.0, 127.8, 127.7, 126.5, 119.5, 115.6, 115.5, 114.6, 114.2, 79.3, 70.2, 46.1, 20.8; MS (ESI⁺): m/z: 763[M+H]⁺. Elemental analysis for C₅₂H₄₂O₆: Calcd. C, 81.87; H, 5.55. Found: C, 81.80; H, 5.53.

(E)-5-(4-(benzyloxy)phenyl)-2-(4-methoxyphenyl)-6-[3-(4-methoxyphenyl)acryloyl]-7-methylchroman-4-one (44)

It was obtained as yellow solid, mp 69–70°C in 91% yield; R_f = 0.4 (7:3 hexane:ethylacetate); IR (KBr): υ_max in cm⁻¹ 3783, 2838, 2362, 1628, 1604, 1509, 1248, 1169, 1027, 830, 728, 561; ¹H NMR (200 MHz, CDCl₃+CCl₄): 7.42–7.20 (m, 9H, 8 ArH & = CH), 7.12–6.80 (m, 10H, ArH), 6.34 (d, J = 16.0 Hz, 1H, = CH), 5.52 (dd, J₁ = 13.1 Hz, J₂ = 2.7 Hz, 1H, CH), 4.95 (m, 2H, OCH₂), 3.84–3.81 (m, 6H, 2 × OCH₃), 3.13 (dd, J₁ = 16.5 Hz, J₂ = 13.2 Hz, 1H, H_a, CH₂), 2.79 (dd, J₁ = 16.5 Hz, J₂ = 2.8 Hz, 1H, H_b, CH₂), 2.29 (s, 3H, CH₃); ¹³C NMR (50 MHz, CDCl₃+CCl₄): δ = 197.7, 190.9 (2 × CO), 162.8, 162.0, 160.4, 158.6, 144.8, 143.5, 141.2, 137.4, 136.6, 131.3, 131.1, 130.6, 130.3, 128.8, 128.1, 128.0, 127.8, 127.5, 126.4, 119.4, 117.1, 114.7, 114.2, 79.2, 70.1, 55.6, 46.2, 20.8; MS (ESI⁺): m/z: 611[M+H]⁺. Elemental analysis for C₄₀H₃₄O₆: Calcd. C, 78.67; H, 5.61. Found: C, 78.65; H, 5.58.

(E)-5-(4-(benzyloxy)phenyl)-2-(3,4-dimethoxyphenyl)-6-[3-(3,4-dimethoxyphenyl)acryloyl]-7-methylchroman-4-one (45)

It was obtained as light yellow solid, mp 138–140°C in 93% yield; R_f = 0.4 (7:3 hexane:ethylacetate); IR (KBr): υ_max in cm⁻¹ 3767, 3427, 2932, 2363, 1594, 1510, 1261, 1150, 1021, 770; ¹H NMR (200 MHz, CDCl₃+CCl₄): δ = 7.32–7.26 (m, 5H, 4 ArH & = CH), 7.11–6.75 (m, 12H, ArH), 6.32 (d, J = 16.0 Hz, 1H, = CH), 5.51 (dd, J₁ = 12.8 Hz, J₂ = 2.6 Hz, 1H, CH), 4.95 (m, 2H, OCH₂), 3.93–3.85 (m, 12H, 4 × OCH₃), 3.13 (dd, J₁ = 16.5 Hz, J₂ = 13.2 Hz, 1H, H_a, CH₂), 2.80 (dd, J₁ = 16.5 Hz, J₂ = 2.8 Hz, 1H, H_b, CH₂), 2.29 (s, 3H, CH₃); ¹³C NMR (50 MHz, CDCl₃+CCl₄): δ = 197.8, 191.0 (2 × CO), 162.7, 158.6, 151.9, 149.9, 149.6, 145.3, 143.7, 137.3, 131.4, 130.6, 128.8, 128.2, 127.8, 126.6, 123.4, 119.2, 114.5, 111.6, 111.4, 110.1, 109.9, 79.5, 70.2, 56.3, 46.3, 20.8. MS (ESI⁺): m/z: 671[M+H]⁺. Elemental analysis for C₄₂H₃₈O₈: Calcd. C, 75.21; H, 5.71. Found: C, 75.12; H, 5.69.

(E)-2-(2-chlorophenyl)-5-(4-chlorophenyl)-6-[3-(2-chlorophenyl)acryloyl]-7-methylchroman-4-one (46)

It was obtained as light yellow solid, mp 190–192°C in 91% yield; R_f = 0.4 (7:3 hexane:ethylacetate); IR (KBr): υ_max in cm⁻¹ 3757, 3065, 2364, 1696, 1591, 1436, 1316, 1161, 1041, 861, 746; ¹H NMR (200 MHz, CDCl₃+CCl₄): δ = 7.76–7.72 (m, 1H, ArH), 7.50–7.23 (m, 11H, 10 ArH & = CH), 7.19–6.98 (m, 2H, ArH), 6.42 (d, J = 16.2 Hz, 1H, = CH), 5.98 (dd, J₁ = 11.7Hz, J₂ = 4.4 Hz, 1H, CH), 2.91–2.84 (m, 2H, CH₂), 2.32 (s, 3H, CH₃); ¹³C NMR (50 MHz, CDCl₃+CCl₄): δ = 197.7, 190.0 (2 × CO), 162.8, 143.8, 141.9, 140.3, 136.9, 135.9, 135.3, 134.0, 133.0, 132.1, 131.7, 131.5, 130.8, 130.5, 130.1, 130.0, 128.3, 128.1, 127.8, 127.5, 119.9, 116.9, 76.5, 44.9, 20.8; MS (ESI⁺): m/z: 547[M+H]⁺. Elemental analysis for C₃₁H₂₁O₃Cl₃: Calcd. C, 67.94; H, 3.86. Found: C, 67.88; H, 3.85.

(E)-5-(4-chlorophenyl)-7-methyl-2-(naphthalen-1-yl)-6-[3-(naphthalen-1-yl)acryloyl]chroman-4-one (47)

It was obtained as light yellow solid, mp 184–185°C in 923% yield; R_f = 0.4 (7:3 hexane:ethylacetate); IR (KBr): υ_max in cm⁻¹ 3778, 3362, 3060, 2920, 2365, 1691, 1639, 1594, 1340, 1180, 1085, 775, 528; ¹H NMR (200 MHz, CDCl₃+CCl₄): δ = 8.10–7.76 (m, 8H, 7 ArH & = CH), 7.59–7.11 (m, 12H, ArH), 6.57 (d, J = 15.8 Hz, 1H, = CH), 6.35 (dd, J₁ = 12.8 Hz, J₂ = 2.7 Hz, 1H, CH), 3. 31 (dd, J₁ = 16.7 Hz, J₂ = 12.9 Hz, 1H, H_a, CH₂), 3.06 (dd, J₁ = 16.7 Hz, J₂ = 2.9 Hz, 1H, H_b, CH₂), 2.39 (s, 3H, CH₃); ¹³C NMR (50 MHz, CDCl₃+CCl₄): δ = 197.4, 190.8 (2 × CO), 163.0, 143.8, 142.7, 140.2, 137.2, 136.5, 134.3, 134.2, 134.1, 132.1, 131.7, 131.4, 131.3, 131.1, 130.9, 130.6, 129.8, 129.5, 129.2, 128.5, 128.3, 127.4, 126.6, 126.4, 125.9, 125.8, 125.7, 124.1, 123.5, 123.1, 120.1, 117.0, 76.90, 45.51, 20.8; MS (ESI⁺): m/z: 579 [M+H]⁺. Elemental analysis for C₃₉H₂₇O₃Cl: Calcd. C, 80.89; H, 4.70. Found: C, 80.81; H, 4.67.

(E)-5-(4-chlorophenyl)-7-methyl-2-(naphthalen-2-yl)-6-[3-(naphthalen-1-yl)acryloyl]chroman-4-one (48)

It was obtained as light yellow solid, mp 184–185°C in 923% yield; R_f = 0.4 (7:3 hexane:ethylacetate); IR (KBr): υ_max in cm⁻¹ 3765, 3412, 2922, 2364, 1636, 1596, 1429, 1183, 1088, 814, 473; ¹H NMR (200 MHz, CDCl₃+CCl₄): δ = 7.94–7.78 (m, 8H, 7 ArH & = CH), 7.62–7.45 (m, 6H, ArH), 7.26–7.01 (m, 6H, ArH), 6.60 (d, J = 16.0 Hz, 1H, = CH), 5.77 (dd, J₁ = 12.9 Hz, J₂ = 2.6 Hz, 1H, CH), 3. 24 (dd, J₁ = 16.5 Hz, J₂ = 13.0 Hz, 1H, H_a, CH₂), 2.93 (dd, J₁ = 16.5 Hz, J₂ = 2.8 Hz, 1H, H_b, CH₂), 2.34 (s, 3H, CH₃); ¹³C NMR (50 MHz, CDCl₃+CCl₄): δ = 197.7, 190.5 (2 × CO), 162.7, 146.2, 143.7, 140.1, 137.1, 136.1, 134.9, 133.9, 133.8, 133.6, 132.1, 131.1, 130.9, 130.7, 129.2, 128.9, 128.7, 128.5, 128.3, 128.2, 127.9, 127.2, 127.0, 125.7, 123.9, 123.7, 120.0, 117.0, 79.75, 46.20, 30.1, 20.8; MS (ESI⁺): m/z: 579 [M+H]⁺. Elemental analysis for C₃₉H₂₇O₃Cl: Calcd. C, 80.89; H, 4.70. Found: C, 80.81; H, 4.67.

Biology

Animal used

Rats (Charles Foster strain, male, adult, body weight 200–225 g) were kept in a room with controlled temperature (25–26°C), humidity (60–80%) and 12/12-h light/dark cycle (light on from 8.00 a.m. to 8.00 p.m.) under hygienic conditions. Animals, which were acclimatized for 1 week before starting the experiment, had free access to the normal diet and water.

Antidyslipidemic activity

The antidyslipidemic activities of all compounds were evaluated in a triton model³⁹. Rats were divided in control, triton induced, triton plus compounds and gemfibrozil (standard drug, 100 mg/kg) treated groups containing six rats in each group. Hyperlipidemia was developed by administration of triton WR-1339 (sigma chemical company, St Louis, MO) at a dose of 400 mg/kg body wt. intraperitoneally to animals of all groups except the control. All the compounds were macerated with gum acacia suspension (vehicle). After 18 h of treatment 3.0 mL, blood was withdrawn from retro-orbital sinus using glass capillary in EDTA coated eppendorf tube (3.0 mg/mL) and plasma was separated. Plasma was diluted with normal saline (ratio 1:3) and used for the analysis of TC, PL, Tg, and protein by standard enzymatic procedures using spectrometer and standard kits purchased from Beckmann Coulter International (USA).

Antioxidant activity determination

Superoxides anions were generated enzymatically²⁸ from xanthine (160 mM) using xanthine oxidase (0.04 U) and nitro blue tetrazolium (320 μM) in the absence or presence of compounds 25–48 (200 μg/mL) in 100 mM phosphate buffer (pH-8.2). Fractions were sonicated well in phosphate buffer before use. The reaction mixtures were incubated at 37°C, and after 30 min, the reaction was stopped by adding 0.5 mL glacial acetic acid. The amount of formazone formed was calculated spectrophotometrically. In another set of experiment, an effect of compounds on generation of hydroxyl radicals (OH·) was also studied by nonenzymatic reactants. Briefly, hydroxyl radicals (OH·) were generated in a nonenzymatic system comprising deoxyribose (2.8 mM), FeSO₄·7H₂O (2.0 mM), sodium ascorbate (2.0 mM) and H₂O₂ (2.8 mM) in 50 mM KH₂ PO₄ buffer, pH 7.4 to a final volume of 2.5 mL. The above reaction mixtures in the absence or presence of test compounds (200 μg/mL) were incubated at 37°C for 90 min. The test compounds were also studied for their inhibitory action against microsomal lipid peroxidation in vitro by non enzymatic inducer. Reference samples and reagent blanks were also run simultaneously. Malondialdehyde content in both experimental and reference samples were estimated spectrophotometriclly by thiobarbituric acid method as mentioned earlier⁴⁰. Alloprinol, mannitol, and α-tocopherol were used as standard drugs for superoxide, hydroxylations and microsomal lipid peroxidations.

Biochemical analysis of plasma/serum

Serum lipids TC⁴¹, Pl⁴², Tg⁴³ and protein⁴⁴ were estimated by the standard procedures reported in literature.

Statistical evaluation

Data were analysed using Student’s t-test. The hyperlipedemic groups were compared with control drug treated groups. Similarly, the generation of oxygen free radicals with different 6-cinnamoyl-7-methyl-5-phenyl-flavanones derivatives were compared with that of their formation without compounds. P < 0.05 was considered to be significant.

Supplementary data

Supplementary data associated with this article can be found, in the online version, at doi:10.3109/14756366.2011.585134.

Declaration of interest

This is CDRI Communication No 8052. The authors thank CSIR and DRDO New Delhi for the SRF and PA to Anindra, Namrata and Rahul, respectively. We are also thankful to the SAIF Division of C.D.R.I. for providing all the spectral data. We sincerely acknowledge the financial assistance from DRDO New Delhi.