IR and NMR spectral studies of some 2-hydroxy-1-naphthyl chalcones: Assessment of substituent effects

Ganesan Vanangamudi; Muthuvel Subramanian; Palanivel Jayanthi; Renganathan Arulkumaran; Dakshnamoorthy Kamalakkannan; Ganesamoorthy Thirunarayanan

doi:10.1016/j.arabjc.2011.07.019

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Original article

9 (

1_suppl

); S717-S724

doi:

10.1016/j.arabjc.2011.07.019

IR and NMR spectral studies of some 2-hydroxy-1-naphthyl chalcones: Assessment of substituent effects

Ganesan Vanangamudi^{^a,⁎}, Muthuvel Subramanian^{^a}, Palanivel Jayanthi^{^a}, Renganathan Arulkumaran^{^a}, Dakshnamoorthy Kamalakkannan^{^a}, Ganesamoorthy Thirunarayanan^{^b}

a PG and Research Department of Chemistry, Government Arts College, C-Mutlur, Chidambaram 608102, India

b Department of Chemistry, Annamalai University, Annamalainagar 608002, India

⁎Corresponding author. Tel.: +91 4144230730. drgvsibi@gmail.com (Ganesan Vanangamudi)

Received: 2011-4-9, Accepted: 2011-7-22, Published: 2011-09-01

Disclaimer:
This article was originally published by Elsevier and was migrated to Scientific Scholar after the change of Publisher.

Peer review under responsibility of King Saud University.

Abstract

A series of substituted styryl 2-hydroxy-1-naphthyl ketones have been synthesized by crossed-Aldol condensation reaction. These ketones are characterized by their physical constants, IR and NMR data. The IR carbonyl stretching and deformation modes ν (cm⁻¹) of vinyl portion frequencies and ¹H and ¹³C NMR spectral chemical shifts δ (ppm) of ethylenic protons, carbons and carbonyl carbons are correlated with various Hammett sigma constants, field, and resonance and Swain–Lupton parameters by single and multi-regression analysis. From the statistical analysis the effect of substituents on the group frequencies is studied.

Keywords

Styryl 2-hydroxy-1-naphthyl ketones

IR and NMR spectra

Hammett substituent constants

Correlation analysis

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1 Introduction

Spectral data of organic compounds are useful for the prediction of their structure, stereo-chemical and physicochemical properties (Thirunarayanan et al., 2010; Wang et al., 2005; Mulliken, 1939 ). The quantitative structure activity relationship and quantitative property relationship of the organic substrates are studied from the spectral data associated with their molecular equilibration (Thirunarayanan, 2007a, 2008a,b ). The vibrational frequencies of carbonyl groups gave two isomeric molecular structures in unsaturated ketones such as s-cis and s-trans conformers. The s-cis carbonyl group absorption frequencies are higher than those of the s-trans carbonyl group. Based on this the structure of molecular equilibration can be predicted in geometrical isomers, keto-enol tautomerism in unsaturated carbonyl compounds (Thirunarayanan, 2007b, 2008b), alkenes, alkynes, styrenes and nitro-styrenes. Nuclear magnetic resonance spectroscopy provides the information about the number of protons present in the molecules and it types either E- or Z in the above said molecules. Based on their coupling constant J in Hz value these types of protons can be identified in the organic molecules. If the molecules possess substituent in the aromatic ring, corresponding absorption frequencies in IR and the chemical shift in NMR vary from ketone to ketone depending upon the type of substituents whether they are electron donating or electron withdrawing in nature. From these data the effect of substituents can be studied on the particular functional group of the molecules by means of regression analysis (Thirunarayanan, 2007b; Thirunarayanan and Ananthakrishna Nadar, 2006a,b; Arul Kumaran et al., 2010 ). Further these data are employed for the study of transition state reaction mechanism (Dass, 2001), structure activity of biological potentials (Deiva et al., 1998), normal coordinate analysis (Sharma et al., 2002; Krishnakumar and Ramasamy, 2002), theoretical study of long range interactions in the beta sheet structures of oligo peptides (Horvath et al., 2005), enone–dienol tautomerism (Wang et al., 2005), density functional theory (Senthilkumar et al., 2006), rotational barriers in selenomides (Kaur et al., 2006) and gas phase reactivity of alkyl sulfides (Izadyar and Gholami, 2006). The out of plane and in-plane deformation frequencies in fingerprint region are also used for QSAR and QPR study (Vanangamudi and Thirunarayanan, 2006). Generally chalcones possess various multipronged activities, (Thirunarayanan, 2008a; Thirunarayanan et al., 2010) such as anticancer, antimicrobial (Sivakumar et al., 2007; Lahtchev et al., 2008), antioxidant (Weber et al., 2005), anti-aids (Deng et al., 2007), insect antifeedant (Thirunarayanan, 2008a; Thirunarayanan et al., 2010), antimalarial (Dominguez et al., 2005), agrochemicals and drugs (Mirinda et al., 2000; Monostory et al., 2003; Nowakowska, 2007; Majinda et al., 2001; Sitaram Kumar et al., 2007 ). These potentials are also applied for the study of structure activity relationships (Sung and Ananthakrishna Nadar, 2000). From thorough literature survey there is no report on the effect of substituents-QSAR or QPR study with these compounds, in the past. Therefore, the authors take effort to synthesise some substituted styryl 2-hydroxy-1-naphthyl ketones and study the correlation analysis with their IR and NMR data.

2 Experimental

2.1

2.1 Synthesis of substituted styryl 2-hydroxy-1-naphthyl ketones

An appropriate equal molar quantity of 2-hydroxy-1-acetylnaphthalene (0.01 mol), various substituted benzaldehydes (0.01 mol), 0.5 g of sodium hydroxide and 20 ml of ethanol were warmed in a 50 ml corning conical flask and shaken occasionally (Thirunarayanan and Ananthakrishna Nadar, 2002) (Scheme 1). The obtained solid was filtered at the pump, washed with cold water and crystallized from ethanol to afford the respective chalcones as a glittering pale yellow solid. The yield of the product was more than 67%. The synthesized chalcones are characterized by their physical constants, IR, ¹H and ¹³C NMR and Mass spectral data. Analytical and Mass spectral data are presented in Table 1. Infrared spectral data are given in Table 2. The ethylenic protons, carbons and carbonyl carbon chemical shifts of the chalcones are presented in Table 4.

Synthesis of 2-hydroxy-1-naphthyl chalcones.

Table 1 Physical constants and analytical data of substituted styryl 2-hydroxy-1-naphthyl ketones.

Entry	X	Mol. formula	Mol. wt.	m.p. (°C)	Found (Calcd) (%) C	H	N	MS Fragmentas (m/z)
1	H	C₁₉H₁₄O₂	274	101–102 (100–101)^a,b	–	–	–	274[M+]
2	3-Br	C₁₉H₁₃BrO₂	352	110–111 (111–112)^b	–	–	–	352[M⁺], 354[M⁺²]
3	4-Br	C₁₉H₁₃BrO₂	352	106–107	64.59 (64.61)	3.68 (3.71)	–	352[M⁺], 354[M⁺²], 335, 208, 197, 180, 171, 154, 143, 79, 55, 17
4	2-Cl	C₁₉H₁₃ClO₂	308	112–13 (113–114)^a,b,c	–	–	–	308[M⁺], 310[M⁺²]
5	3-Cl	C₁₉H₁₃ClO₂	308	102–103 (103–104)^c	–	–	–	308[M⁺], 310[M⁺²], 291, 273, 197, 171, 165, 143, 137, 111, 77, 35, 17
6	4-Cl	C₁₉H₁₃ClO₂	308	86-87 (87–88)^c	–	–	–	308[M⁺], 310[M⁺²], 273, 197, 171, 165, 143, 137, 111, 77, 55, 17
7	2-OH	C₁₉H₁₄O₃	290	73–74 (75–76)^a,b	–	–	–	290[M⁺]
8	4-OH	C₁₉H₁₄O₃	290	71–72 (72–73)^c	–	–	–	290[M⁺], 273, 197, 171, 147, 143, 93, 77, 17
9	2-OCH₃	C₂₀H₁₆O₃	304	81–82 (82–83)^d	–	–	–	304[M⁺], 287, 273, 197, 171, 161, 143, 107, 91, 77, 55, 17
10	4-CH₃	C₂₀H₁₆O₂	288	97–98 (98–99)^a,c,d	–	–	–	288[M⁺]
11	2-NO₂	C₁₉H₁₃NO₄	319	116–17	71.52 (71.47)	4.06 (4.10)	4.42 (4.39)	319[M⁺], 302, 273, 197, 176, 171, 143, 122, 45, 17
12	4-NO₂	C₁₉H₁₃NO₄	319	126–127 (125–126)^a	–	–	–	319[M⁺], 302, 273, 197, 176, 143, 122, 55, 77, 45, 17

a (Rajendra Prasad et al., 2008).

b (Rao et al., 1972).

c (Misra and Dinkar, 1972a,b).

d (Misra and Dinkar, 1972a,b).

Table 2 Infrared stretches ν (cm⁻¹) CO_s-cis, CO_s-trans, CH_ip, CH_op, CH⚌CH_op and C⚌C_op of substituted styryl 2-hydroxy-1-naphthyl ketones.

Entry	Substituent	CO_s-cis	CO_s-trans	CH_ip	CH_op	CH⚌CH_op	C⚌C_op
1	H	1653.60	1610.96	1148.65	740.58	1074.42	592.96
2	3-Br	1659.58	1594.11	1147.68	751.67	1072.92	501.71
3	4-Br	1656.50	1619.25	1150.23	753.55	1073.25	593.67
4	2-Cl	1661.74	1612.97	1163.25	752.17	1083.95	592.07
5	3-Cl	1658.05	1595.95	1149.48	753.73	1016.83	593.75
6	4-Cl	1657.34	1619.74	1149.40	753.06	1091.14	594.42
7	2-OH	1699.41	1637.37	1171.05	754.36	1079.91	566.64
8	4-OH	1627.40	1584.69	1124.84	753.73	1015.81	598.43
9	2-OCH₃	1657.75	1615.13	1124.01	760.77	1019.61	596.68
10	4-CH₃	1656.24	1610.73	1117.25	782.27	995.74	589.79
11	2-NO₂	1657.75	1615.13	1117.97	751.71	1073.96	574.95
12	3-NO₂	1668.22	1608.59	1145.21	767.35	1020.23	538.10

The melting points of chalcones were determined in sigma melting point apparatus and are uncorrected. The IR spectra of all chalcones are recorded using KBr pellets in a Perkin Elmer Japan model Fourier Transform Spectrophotometer. The ¹H NMR spectra of all chalcones were recorded in a Bruker 300MHz model Spectrometer at Sastra University, Tanjore.

3 Results and discussion

3.1

3.1 Infrared spectral study

During the vibrations these synthesized chalcones exist as s-cis and s-trans conformers. These conformers are confirmed by the carbonyl group doublets obtained in the range of 1600–1700 cm⁻¹. They are shown in Fig. 1 and the corresponding carbonyl frequencies (cm⁻¹) of the conformers are presented in Table 2. The s-cis conformers absorb at higher vibrational frequencies than s-trans conformers. Generally carbonyl doublets are obtained at lower absorption frequencies for the electron donating substituents in the chalcones whereas the electron withdrawing substituents absorb their doublets at higher frequencies in both the conformers. In this present study also, the same trend was observed. These frequencies are correlated with various Hammett sigma constants and Swain–Lupton’s parameters (Swain and Lupton, 1968) by single and multi linear regression analysis. While seeking Hammett correlation involving group frequencies, the form of the Hammett equation employed is

(1)

ν = ρ σ + ν_{0}

where ν₀ is the frequency for the parent member of the series.

The results of single parameter statistical analysis of carbonyl frequencies with substituent constants are presented in Table 3.

Table 3 Results of statistical analysis of infrared ν (cm⁻¹) CO_s-cis, CO_s-trans, CH_ip, CH_op, CH⚌CH_op and C⚌C_op substituted styryl-2-hydroxy-1-naphthyl ketones with Hammett σ, σ⁺, σ_I,, σ_R constants and F and R parameters.

Frequency	Constants	r	I	ρ	s	n	Correlated derivatives
CO_s-cis	σ	0.967	1650.94	26.699	11.46	10	H, 3-Br, 4-Br, 2-Cl, 3-Cl, 4-Cl, 2-OCH₃, 4-CH₃, 2-NO₂, 4-NO₂
	σ⁺	0.975	1653.23	22.812	10.26	10	H, 3-Br, 4-Br, 2-Cl, 3-Cl, 4-Cl, 2-OCH₃, 4-CH₃, 2-NO₂, 4-NO₂
	σ_I	0.947	1652.51	32.306	13.68	10	H, 3-Br, 4-Br, 2-Cl, 3-Cl, 4-Cl, 2-OCH₃, 4-CH₃, 2-NO₂, 4-NO₂
	σ_R	0.863	1663.79	38.460	12.06	12	H, 3-Br, 4-Br, 2-Cl, 3-Cl, 4-Cl, 2-OH, 4-OH, 3-OCH₃, 4-OCH₃, 3-NO₂, 4-NO₂
	F	0.838	1644.48	25.912	14.36	12	H, 3-Br, 4-Br, 2-Cl, 3-Cl, 4-Cl, 3-OH, 4-OH, 3-OCH₃, 4-OCH₃, 3-NO₂, 4-NO₂
	R	0.872	1644.83	36.447	10.78	12	H, 3-Br, 4-Br, 2-Cl, 3-Cl, 4-Cl, 3-OH, 4-OH, 3-OCH₃, 4-OCH₃, 3-NO₂, 4-NO₂
CO_s-trans	σ	0.811	1609.45	−4.236	13.99	12	H, 3-Br, 4-Br, 2-Cl, 3-Cl, 4-Cl, 3-OH, 4-OH, 3-OCH₃, 4-OCH₃, 3-NO₂, 4-NO₂
	σ⁺	0.901	1608.84	0.053	14.03	12	H, 3-Br, 4-Br, 2-Cl, 3-Cl, 4-Cl, 3-OH, 4-OH, 3-OCH₃, 4-OCH₃, 3-NO₂, 4-NO₂
	σ_I	0.819	1613.47	−12.202	13.75	12	H, 3-Br, 4-Br, 2-Cl, 3-Cl, 4-Cl, 3-OH, 4-OH, 3-OCH₃, 4-OCH₃, 3-NO₂, 4-NO₂
	σ_R	0.813	1607.13	-7.297	13.90	12	H, 3-Br, 4-Br, 2-Cl, 3-Cl, 4-Cl, 3-OH, 4-OH, 3-OCH₃, 4-OCH₃, 3-NO₂, 4-NO₂
	F	0.822	1614.26	−13.633	13.67	12	H, 3-Br, 4-Br, 2-Cl, 3-Cl, 4-Cl, 3-OH, 4-OH, 3-OCH₃, 4-OCH₃, 3-NO₂, 4-NO₂
	R	0.803	1609.30	1.665	14.02	12	H, 3-Br, 4-Br, 2-Cl, 3-Cl, 4-Cl, 3-OH, 4-OH, 3-OCH₃, 4-OCH₃, 3-NO₂, 4-NO₂
CH_ip	σ	0.906	1143.24	2.281	18.06	10	H, 3-Br, 4-Br, 2-Cl, 3-Cl, 4-Cl, 2-OCH₃, 4-CH₃, 2-NO₂, 4-NO₂
	σ⁺	0.918	1143.21	6.149	17.79	10	H, 3-Br, 4-Br, 2-Cl, 3-Cl, 4-Cl, 2-OCH₃, 4-CH₃, 2-NO₂, 4-NO₂
	σ_I	0.817	1138.46	13.674	17.82	12	H, 3-Br, 4-Br, 2-Cl, 3-Cl, 4-Cl, 3-OH, 4-OH, 3-OCH₃, 4-OCH₃, 3-NO₂, 4-NO₂
	σ_R	0.925	1139.36	−18.273	17.48	10	H, 3-Br, 4-Br, 2-Cl, 3-Cl, 4-Cl, 2-OCH₃, 4-CH₃, 2-NO₂, 4-NO₂
	F	0.821	1136.81	17.211	17.65	12	H, 3-Br, 4-Br, 2-Cl, 3-Cl, 4-Cl, 3-OH, 4-OH, 3-OCH₃, 4-OCH₃, 3-NO₂, 4-NO₂
	R	0.916	1140.94	−9.798	17.84	10	H, 3-Br, 4-Br, 2-Cl, 3-Cl, 4-Cl, 2-OCH₃, 4-CH₃, 2-NO₂, 4-NO₂
CH_op	σ	0.901	756.06	−2.725	10.42	10	H, 3-Br, 4-Br, 2-Cl, 3-Cl, 4-Cl, 2-OCH₃, 4-CH₃, 2-NO₂, 4-NO₂
	σ⁺	0.903	755.83	−9.826	10.23	10	H, 3-Br, 4-Br, 2-Cl, 3-Cl, 4-Cl, 2-OCH₃, 4-CH₃, 2-NO₂, 4-NO₂NO₂
	σ_I	0.821	759.40	−9.826	10.41	12	H, 3-Br, 4-Br, 2-Cl, 3-Cl, 4-Cl, 3-OH, 4-OH, 3-OCH₃, 4-OCH₃, 3-NO₂, 4-NO₂
	σ_R	0.911	756.73	4.747	10.41	10	H, 3-Br, 4-Br, 2-Cl, 3-Cl, 4-Cl, 2-OCH₃, 4-CH₃, 2-NO₂, 4-NO₂
	F	0.920	759.45	−9.506	10.25	10	H, 3-Br, 4-Br, 2-Cl, 3-Cl, 4-Cl, 2-OCH₃, 4-CH₃, 2-NO₂, 4-NO₂
	R	0.808	756.44	2.772	10.44	12	H, 3-Br, 4-Br, 2-Cl, 3-Cl, 4-Cl, 3-OH, 4-OH, 3-OCH₃, 4-OCH₃, 3-NO₂, 4-NO₂
CH⚌CH_op	σ	0.822	1051.95	20.989	35.82	12	H, 3-Br, 4-Br, 2-Cl, 3-Cl, 4-Cl, 3-OH, 4-OH, 3-OCH₃, 4-OCH₃, 3-NO₂, 4-NO₂
	σ⁺	0.827	1053.61	19.982	35.30	12	H, 3-Br, 4-Br, 2-Cl, 3-Cl, 4-Cl, 3-OH, 4-OH, 3-OCH₃, 4-OCH₃, 3-NO₂, 4-NO₂
	σ_I	0.831	1035.73	50.714	34.88	12	H, 3-Br, 4-Br, 2-Cl, 3-Cl, 4-Cl, 3-OH, 4-OH, 3-OCH₃, 4-OCH₃, 3-NO₂, 4-NO₂
	σ_R	0.808	1051.92	-12.964	36.61	12	H, 3-Br, 4-Br, 2-Cl, 3-Cl, 4-Cl, 3-OH, 4-OH, 3-OCH₃, 4-OCH₃, 3-NO₂, 4-NO₂
	F	0.835	1032.52	56.526	34.38	12	H, 3-Br, 4-Br, 2-Cl, 3-Cl, 4-Cl, 3-OH, 4-OH, 3-OCH₃, 4-OCH₃, 3-NO₂, 4-NO₂
	R	0.801	1054.32	13.132	36.75	12	H, 3-Br, 4-Br, 2-Cl, 3-Cl, 4-Cl, 3-OH, 4-OH, 3-OCH₃, 4-OCH₃, 3-NO₂, 4-NO₂
C⚌C_op	σ	0.836	577.72	−32.960	31.93	12	H, 3-Br, 4-Br, 2-Cl, 3-Cl, 4-Cl, 3-OH, 4-OH, 3-OCH₃, 4-OCH₃, 3-NO₂, 4-NO₂
	σ⁺	0.832	574.62	−21.928	32.43	12	H, 3-Br, 4-Br, 2-Cl, 3-Cl, 4-Cl, 3-OH, 4-OH, 3-OCH₃, 4-OCH₃, 3-NO₂, 4-NO₂
	σ_I	0.938	595.27	−54.296	31.63	10	H, 3-Br, 4-Br, 2-Cl, 3-Cl, 4-Cl, 2-OCH₃, 4-CH₃, 2-NO₂, 4-NO₂
	σ_R	0.804	571.66	−65.296	34.28	12	H, 3-Br, 4-Br, 2-Cl, 3-Cl, 4-Cl, 3-OH, 4-OH, 3-OCH₃, 4-OCH₃, 3-NO₂, 4-NO₂
	F	0.950	605.12	−80.557	28.90	10	H, 3-Br, 4-Br, 2-Cl, 3-Cl, 4-Cl, 2-OCH₃, 4-CH₃, 2-NO₂, 4-NO₂
	R	0.826	572.32	−21.992	34.30	12	H, 3-Br, 4-Br, 2-Cl, 3-Cl, 4-Cl, 3-OH, 4-OH, 3-OCH₃, 4-OCH₃, 3-NO₂, 4-NO₂

r = Correlation coefficient; ρ = Slope; I = Intercept; s = Standard deviation; n = Number of substituents.

The s-cis carbonyl frequencies are correlated satisfactorily with Hammett σ and σ⁺ constants. All correlations produce positive ρ values. This shows that the normal substituent effects operate in all the conformers. The inductive and resonance effects of the substituents fail in correlations. This is due to the inability to transmit the substituent effect on carbonyl group. Also the inductive effect of the substituents dies off considerably. This is illustrated in the resonance-conjugative structure shown in Fig. 1. The substituent effects get reduced, since the substituents are away from three or more carbon bond lengths and this leads to poor correlation. The s-trans carbonyl frequencies are found to fail in correlation with any of the substituent constants. This is due to the same reasons as stated earlier for s-cis conformers. The ability of transmission of substituent effect on carbonyl group is higher in s-cis conformers than in s-trans conformers.

The assigned in-plane and out of plane deformation modes CH_ip, CH_op, CH⚌CH_op and C⚌C_op (cm⁻¹) of 2-hydroxy-1-naphthyl ketones are presented in Table 2. The larger value of deformation mode frequency for the system is due to the low mobility of electron between the >C⚌C< and the –CH = CH– frame work.

All the deformation modes substituted styryl 2-hydroxy-1-naphthyl ketones are correlated with different substituent constants according to John shorter (Thirunarayanan et al., 2011; Shorter, 1973). The results of statistical analysis are shown in Table 3.

The correlation of –CH in-plane deformation stretches with σ_R parameter seems to be good. The correlation with σ_I and F values is quite bad. This is due to the fact that these values are not capable of predicting the substituent effects on CH in-plane vibrations. The correlations with σ⁺ values are better. All correlations produce positive ρ values, except σ_I and F parameters. This shows that normal substituent operates in all systems, excluding some of the substituents like 4-OH, 4-CH₃ and 2-OCH₃. The failure in correlations due to complete dies off resonance effect of substituent.

The observed –CH_op modes of substituted styryl 2-hydroxy-1-naphthyl ketones are given in Table 2. All the deformation modes of substituted styryl 2-hydroxy-1-naphthyl ketones are correlated with different substituent constants according to (Thirunarayanan et al., 2011; Shorter, 1973). The results of statistical analysis are shown in Table 3. The correlation of –CH out of plane deformation modes with σ, σ⁺, σ_R and F parameters seems to be satisfactory. The correlations with σ_I and R values are quite bad. This is due to the fact that these values are not capable of predicting the substituent effects on –CH– out of plane vibrations and the resonance effect of substituents completely dies off. This is shown in the conjugative structure in Fig. 1 which the pi-bond character is converted into the sigma character.

The observed CH⚌CH out of plane frequencies in the present study are given in Table 2. All the deformation CH⚌CH_op modes of stretching frequencies of substituted styryl 2-hydroxy-1-naphthyl ketones are correlated with different substituent constants according to (Thirunarayanan et al., 2011; Shorter, 1973). The results of statistical analysis are shown in Table 3. All correlations fail in this mode of frequencies with Hammett substituent constants and F and R parameters using single regression analysis.

The observed >C⚌C< op frequencies in the present study are given in Table 2. All the frequencies of deformation modes of substituted styryl 2-hydroxy-1-naphthyl ketones are correlated with different substituent constants according to (Thirunarayanan et al., 2011; Shorter, 1973). The results of statistical analysis are shown in Table 3. The correlation of >C⚌C< out of plane deformation modes with σ_I and F parameters seem to be satisfactory excluding selective substituents. If they are included in the regression, they reduce the correlation considerably. The correlation with σ, σ⁺, σ_R and R values is quite bad. This is due to the fact that these values are not capable of predicting the substituent effects on >C⚌C< out of plane vibrations and the resonance effect of substituents completely dies off. This is shown in the conjugative structure in Fig. 1 in which the pi-bond character is converted into the sigma character.

Some of the single parameter correlations fail with the infrared CO_s-cis, CH_ip, CH_op, CH⚌CH_op and C⚌C_op with Hammett sigma constants and F and R parameters. While seeking the multi regression analysis of these stretches, satisfactory correlations are obtained with Swain–Lupton and F and R parameters. The correlated multi regression equations are given in 2–13

(2)

ν {CO}_{s - cis}^{({cm}^{- 1})} = 1653.48 (\pm 7.809) + 24.430 (\pm 1.521) σ_{I} + 33.91 (\pm 1.363) σ_{R} (R = 0.972, n = 12, P > 95 %)

(3)

ν {CO}_{s - cis}^{({cm}^{- 1})} = 1605.44 (\pm 6.566) + 22.883 (\pm 1.299) F + 35.351 (\pm 9.721) R (R = 0.979, n = 12, P > 95 %)

(4)

ν {CO}_{s - trans}^{({cm}^{- 1})} = 1611.78 (\pm 9.941) - 10.984 (\pm 1.937) σ_{I} - 5.251 (\pm 1.735) σ_{R} (R = 0.921, n = 12, P > 90 %)

(5)

ν {CO}_{s - trans}^{({cm}^{- 1})} = 1614.98 (\pm 9.561) - 13.833 (\pm 1.883) F + 2.328 (\pm 1.409) R (R = 0.922, n = 12, P > 90 %)

(6)

ν {CH}_{op} ({cm}^{- 1}) = 1131.443 (\pm 12.329 + 18.724 (\pm 24.020) σ_{1} - 21.769 (\pm 21.520) σ_{R} (R = 0.900, P > 90 %, n = 13)

(7)

ν {CH}_{op} ({cm}^{- 1}) = 1133.50 (\pm 12.091) + 18.125 (\pm 2.934) F - 10.667 (\pm 1.702) R (R = 0.90, P > 90 %, n = 13)

(8)

ν {CH}_{ip} ({cm}^{- 1}) = 1028.17 (\pm 24.974) + 56.149 (\pm 4.672) σ_{1} - 23.422 (\pm 4.324) σ_{R} (R = 0.900, P > 90 %, n = 13)

(9)

ν {CH}_{ip} ({cm}^{- 1}) = 1032.09 (\pm 23.958) + 56.64 (\pm 27.212) F - 1.400 (\pm 3.547) R (R = 0.90, P > 90 %, n = 13)

(10)

ν - CH = {CH}_{op} ({cm}^{- 1}) = 761.62 (\pm 7.329) - 11.422 (\pm 14.283) σ_{1} + 6.874 (\pm 12.795) σ_{R} (R = 0.926, P > 90 %, n = 13)

(11)

ν - CH = {CH}_{op} ({cm}^{- 1}) = 760.457 (\pm 14.071) - 9.784 (\pm 2.710) F + 3.241 (\pm 1.525) R (R = 0.922, P > 90 %, n = 13)

(12)

ν > C = C < op ({cm}^{- 1}) = 596.77 (\pm 22.955) - 59.388 (\pm 4.732) σ_{1} + 4.708 (\pm 4.072) σ_{R} (R = 0.938, P > 90 %, n = 13)

(13)

ν > C = C < op ({cm}^{- 1}) = 605.39 (\pm 20.137) - 80.627 (\pm 39.861) F + 0.827 (\pm 29.815) R (R = 0.953, P > 95 %, n = 13)

3.2

3.2 ¹H spectral study

The ¹H NMR spectra of nine chalcones under investigation are recorded in deuterated dimethyl sulfoxide employing tetramethylsilane (TMS) as the internal standard. The signals of the ethylenic protons were assigned. They are calculated as AB or AA′ BB′ systems, respectively, (Thirunarayanan et al., 2011; Laturber, 1961; Solcaniova and Toma, 1980; Thirunarayanan, 2008a,b ). The chemical shifts of H_α are at higher field than those of H_β in this series of ketones. The ethylenic protons give an AB pattern and the β-proton doublet in most cases is well separated from the signals of the aromatic protons. The assigned chemical shifts of the ethylenic protons are presented in Table 4.

Table 4 The chemical shifts (ppm) of vinyl protons, carbons and carbonyl carbons of substituted styryl-2-hydroxy-1-naphthyl ketones.

Entry	Substituent	δH_α	δH_β	δC_α	δC_β	δCO
1	H	7.631	7.939	124.87	137.52	192.92
2	3-Br	7.229	7.736	124.59	137.70	192.31
3	4-Br	7.225	7.725	124.99	137.66	192.42
4	2-Cl	6.734	7.586	124.93	138.96	182.93
5	3-Cl	7.212	7.991	124.09	137.62	192.20
6	4-Cl	7.196	7.984	124.99	137.65	192.46
7	2-OH	6.833	7.683	124.56	137.99	192.41
8	4-OH	7.263	7.852	124.98	137.64	192.67
9	2-OCH₃	7.263	7.852	124.86	137.50	193.14
10	4-CH₃	7.233	8.482	121.13	137.90	191.66
11	2-NO₂	6.977	7.650	124.81	137.39	193.05
12	3-NO₂	7.301	8.300	124.89	139.35	194.13

In nuclear magnetic resonance spectra, the proton chemical shifts δ (ppm) depend on the electronic environment of the nuclei concerned. These shifts can be correlated with reactivity parameters. Thus the Hammett equation may be used in the form as

(14)

Log δ = Log δ_{0} + ρ σ

where δ₀ is the chemical shift in the corresponding parent compound.

The assigned ¹H NMR chemical shifts (ppm) of δH_α and δH_β of substituted styryl 2-hydroxy-1-naphthyl ketones are presented in Table 4. These chemical shifts are correlated with Hammett substituent constants and F and R parameters. The results of statistical analysis of these chemical shifts (ppm) are shown in Table 5. Hammett substituent constants, F and R parameters fail correlations with δH_α and δH_β chemical shifts. Hammet σ⁺, σ_R and F and R parameter correlations gave positive ρ values. This shows that the normal substituent effects operated in all ketones. The remaining Hammett constants produce negative ρ values. These constants reverse the substituent effects in overall correlations on both the chemical shifts. This is due to the incapability of predicting the substituent effects on the vinyl protons by the substituents along with the Hydrogen bonding on carbonyl carbon in the conjugative structure in Fig. 1. The degree of transmission of substituent effects on δH_α is higher than δH_β chemical shifts.

Table 5 Results of statistical analysis of ¹H NMR chemical shifts of δH_α and δH_β (ppm) protons and ¹³C NMR chemical shifts of δC_α, δC_βand δCO (ppm) carbons of substituted styryl-2-hydroxy-1-naphthyl ketones with Hammett substituent constants σ, σ⁺, σ_I, σ_R, F and R parameters.

Frequency	Constants	r	ρ	I	s	n	Correlated derivatives
$δ_{H α}^{(ppm)}$	σ	0.807	−0.037	7.174	0.24	12	H, 3-Br, 4-Br, 2-Cl, 3-Cl, 4-Cl, 2-OH, 4-OH, 2-OCH₃, 4-CH₃, 2-NO₂, 3-NO₂
	σ⁺	0.813	0.051	7.173	0.24	12	H, 3-Br, 4-Br, 2-Cl, 3-Cl, 4-Cl, 2-OH, 4-OH, 2-OCH₃, 4-CH₃, 2-NO₂, 3-NO₂
	σ_I	0.798	−0.383	7.309	0.22	12	H, 3-Br, 4-Br, 2-Cl, 3-Cl, 4-Cl, 2-OH, 4-OH, 2-OCH₃, 4-CH₃, 2-NO₂, 3-NO₂
	σ_R	0.827	0.315	7.230	0.22	12	H, 3-Br, 4-Br, 2-Cl, 3-Cl, 4-Cl, 2-OH, 4-OH, 2-OCH₃, 4-CH₃, 2-NO₂, 3-NO₂
	F	0.813	−0.467	7.347	0.22	12	H, 3-Br, 4-Br, 2-Cl, 3-Cl, 4-Cl, 2-OH, 4-OH, 2-OCH₃, 4-CH₃, 2-NO₂, 3-NO₂
	R	0.817	0.221	7.224	0.23	12	H, 3-Br, 4-Br, 2-Cl, 3-Cl, 4-Cl, 2-OH, 4-OH, 2-OCH₃, 4-CH₃, 2-NO₂, 3-NO₂

$δ_{H β}^{(ppm)}$	σ	0.760	−0.052	7.915	0.27	12	H, 3-Br, 4-Br, 2-Cl, 3-Cl, 4-Cl, 2-OH, 4-OH, 2-OCH₃, 4-CH₃, 2-NO₂, 3-NO₂
	σ⁺	0.813	−0.070	7.914	0.27	12	H, 3-Br, 4-Br, 2-Cl, 3-Cl, 4-Cl, 2-OH, 4-OH, 2-OCH₃, 4-CH₃, 2-NO₂, 3-NO₂
	σ_I	0.831	−0.422	8.063	0.26	12	H, 3-Br, 4-Br, 2-Cl, 3-Cl, 4-Cl, 2-OH, 4-OH, 2-OCH₃, 4-CH₃, 2-NO₂, 3-NO₂
	σ_R	0.823	0.285	7.964	0.27	12	H, 3-Br, 4-Br, 2-Cl, 3-Cl, 4-Cl, 2-OH, 4-OH, 2-OCH₃, 4-CH₃, 2-NO₂, 3-NO₂
	F	0.834	−0.455	8.071	0.26	12	H, 3-Br, 4-Br, 2-Cl, 3-Cl, 4-Cl, 2-OH, 4-OH,2-OCH₃, 4-CH₃, 2-NO₂, 3-NO₂
	R	0.827	0.235	7.965	0.27	12	H, 3-Br, 4-Br, 2-Cl, 3-Cl, 4-Cl, 2-OH, 4-OH, 2-OCH₃, 4-CH₃, 2-NO₂, 3-NO₂

$δ_{C α}^{(ppm)}$	σ	0.921	0.600	124.38	1.10	12	H, 3-Br, 4-Br, 3-Cl, 4-Cl, 2-OH, 4-OH, 2-OCH₃, 4-CH₃, 2-NO₂, 3-NO₂
	σ⁺	0.920	0.424	124.43	1.11	12	H, 3-Br, 4-Br, 3-Cl, 4-Cl, 2-OH, 4-OH, 2-OCH₃, 4-CH₃, 2-NO₂, 3-NO₂
	σ_I	0.851	2.715	123.48	1.13	12	H, 3-Br, 4-Br, 3-Cl, 4-Cl, 2-OH, 4-OH,2-OCH₃, 4-CH₃, 2-NO₂, 3-NO₂
	σ_R	0.805	−0.369	124.10	1.13	12	H, 3-Br, 4-Br, 3-Cl, 4-Cl, 2-OH, 4-OH, 2-OCH₃, 4-CH₃, 2-NO₂, 3-NO₂
	F	0.853	2.849	123.42	0.96	12	H, 3-Br, 4-Br, 3-Cl, 4-Cl, 2-OH, 4-OH, 2-OCH₃, 4-CH₃, 2-NO₂, 3-NO₂
	R	0.905	−0.228	124.42	1.13	12	H, 3-Br, 4-Br, 3-Cl, 4-Cl, 2-OH, 4-OH, 2-OCH₃, 4-CH₃, 2-NO₂, 3-NO₂

$δ_{C β}^{(ppm)}$	σ	0.902	−0.466	137.84	0.61	10	H, 3-Br, 4-Br, 3-Cl, 4-Cl, 2-OH, 4-OH, 2-OCH₃, 4-CH₃, 2-NO₂, 3-NO₂
	σ⁺	0.903	−0.407	137.87	0.60	10	H, 3-Br, 4-Br, 3-Cl, 4-Cl, 2-OH, 4-OH, 2-OCH₃, 4-CH₃, 2-NO₂
	σ_I	0.903	−0.850	137.59	0.609	10	H, 3-Br, 4-Br, 3-Cl, 4-Cl, 2-OH, 4-OH, 2-OCH₃, 4-CH₃, 2-NO₂
	σ_R	0.902	−0.509	138.01	0.62	10	H, 3-Br, 4-Br, 3-Cl, 4-Cl, 2-OH, 4-OH, 2-OCH₃, 4-CH₃, 2-NO₂
	F	0.900	−0.952	137.56	0.60	10	H, 3-Br, 4-Br, 3-Cl, 4-Cl, 2-OH, 4-OH, 2-OCH₃, 4-CH₃, 2-NO₂
	R	0.921	0.509	138.03	0.62	10	H, 3-Br, 4-Br, 3-Cl, 4-Cl, 2-OH, 4-OH, 2-OCH₃, 4-CH₃, 2-NO₂

$δ_{CO}^{(ppm)}$	σ	0.913	0.302	191.81	3.01	11	H, 3-Br, 4-Br, 3-Cl, 4-Cl, 2-OH, 4-OH, 2-OCH₃, 4-CH₃, 2-NO₂, 3-NO₂
	σ⁺	0.941	0.784	191.94	2.96	11	H, 3-Br, 4-Br, -Cl, 4-Cl, 2-OH, 4-OH, 2-OCH₃, 4-CH₃, 2-NO₂, 3-NO₂
	σ_I	0.940	−0.533	192.06	3.01	11	H, 3-Br, 4-Br, -Cl, 4-Cl, 2-OH, 4-OH, 2-OCH₃, 4-CH₃, 2-NO₂, 3-NO₂
	σ_R	0.912	1.450	192.15	2.99	11	H, 3-Br, 4-Br, -Cl, 4-Cl, 2-OH, 4-OH, 2-OCH₃, 4-CH₃, 2-NO₂, 3-NO₂
	F	0.902	0.387	191.72	3.01	11	H, 3-Br, 4-Br, -Cl, 4-Cl, 2-OH, 4-OH, 2-OCH₃, 4-CH₃, 2-NO₂, 3-NO₂
	R	0.905	0.536	191.99	3.01	11	H, 3-Br, 4-Br, -Cl, 4-Cl, 2-OH, 4-OH, 2-OCH₃, 4-CH₃, 2-NO₂, 3-NO₂

r = Correlation coefficient; ρ = Slope; I = Intercept; s = Standard deviation; n = Number of substituents.

Some of the single parameter correlations fail with the ¹H NMR of δH_α and δH_β chemical shifts with Hammett sigma constants and F and R parameters. While seeking the multi regression analysis of these frequencies, satisfactory correlations are obtained with Swain–Lupton and F and R parameters. The correlated multi regression equations are (15–18)

(15)

δ H_{α} (ppm) = 7.468 (\pm 0.145) - 0.559 (\pm 0.234) σ_{I} + 0.478 (\pm 0.251) σ_{R} (R = 0.906, n = 12, P > 90 %)

(16)

δ H_{α} (ppm) = 7.4714 (\pm 0.157) - 0.594 (\pm 0.324) F + 0.334 (\pm 0.020) R (R = 0.905, n = 12, P > 90 %)

(17)

δ H_{β} (ppm) = 8.215 (\pm 0.175) - 0.592 (\pm 0.359) σ_{I} + 0.457 (\pm 0.318) σ_{R} (R = 0.953, n = 12, P > 95 %)

(18)

δ H_{β} (ppm) = 8.209 (\pm 0.192) - 0.586 (\pm 0.395) F + 0.349 (\pm 0.021) R (R = 0.949, n = 12, P > 90 %)

3.3

3.3 ¹³C NMR spectral study

The assigned carbonyl carbon chemical shifts (ppm) of δCO, δC_α and δC_β of 2-hydroxy-1-naphthyl ketones are presented in Table 4 and these chemical shifts are correlated with Hammett sigma constants and F and R parameters. The results of statistical analysis are shown in Table 5. From the table Hammett σ constants, F and R parameters correlated satisfactorily alongwith positive ρ values excluding 2-Cl substituent. This shows the normal substituent effects in all ketones. Inductive effects of the substituent produced negative ρ value and it leads to reversal substituent effect.

The assigned vinyl carbon C_α and C_β chemical shifts (ppm) of 2-hydroxy-1-naphthyl ketones ketones are correlated with Hammett sigma constants and F and R parameters. The results of statistical analysis are shown in Table 5. The C_α chemical shifts correlated with Hammett σ, σ+ constants and R parameters the ρ values are found to be positive. This shows that the normal substituent effects operate in all ketones.The Inductive, resonance and Field effects of the substituents fail in correlation. The resonanace parameters produce negative ρ values. This is due to the reason stated earlier along with the conjugated structure in Fig. 1.

The C_β chemical shifts (ppm) of 2-hydroxy-1-naphthyl ketones are correlated with Hammett sigma constants and F and R parameters along with negative ρ values excluding 2-Cl and 3-NO₂ substituents. This shows that the reversal substituent effects operate in all ketones. The degree of transmission of substituent effects on C_β is more than C_α carbons.

Single parameter correlations fail with the ¹³C NMR of δC_α and δC_β chemical shifts (ppm) with Hammett sigma constants and F and R parameters. While seeking the multi regression analysis of these frequencies, satisfactory correlations are obtained with Swain–Lupton and F and R parameters. The correlated multi regression equations are given in 19–24.

(19)

δ {CO}^{(ppm)} = 192.65 (\pm 2.251) - 1.199 (\pm 0.4523) σ_{I} + 1.798 (\pm 0.413) σ_{R} (R = 0.915, n = 12, P > 90 %)

(20)

δ {CO}^{(ppm)} = 191.91 (\pm 2.382) + 0.203 (\pm 0.428) F + 0.497 (\pm 0.035) R (R = 0.905, n = 12, P > 90 %)

(21)

δ_{C_{α}}^{(ppm)} = 123.04 (\pm 0.671) + 3.195 (\pm 1.2350) σ_{I} - 1.297 (\pm 0.513) σ_{R} (R = 0.962, n = 12, P > 95 %)

(22)

δ_{C_{α}}^{(ppm)} = 123.10 (\pm 0.736) + 3.161 (\pm 1.152) F - 0.084 (\pm 0.094) R (R = 0.955, n = 12, P > 95 %)

(23)

δ_{C_{β}}^{(ppm)} = 137.69 (\pm 0.457) + 0.741 (\pm 0.091) σ_{I} + 0.294 (\pm 0.081) σ_{R} (R = 0.928, n = 12, P > 90 %)

(24)

δ_{C_{β}}^{(ppm)} = 137.69 (\pm 1.474) + 0.823 (\pm 0.097) F + 0.350 (\pm 0.051) R (R = 0.935, n = 12, P > 90 %)

Acknowledgement

The authors are thankful to The Head, CARISM, Sastra University, Tanjore for recording NMR spectra of all compounds.

References

Arul Kumaran R., Sundararajan R., Vanagamudi G., Subramanian M., Ravi K., Sathiyendiran V., Srinivasan S., Thirunarayanan G., . IUP J. Chem.. 2010;3(1):82.
Dass G.K., . Indian J. Chem.. 2001;40(A1):23.
Deiva C.M., Pappano N.B., Debattista N.B., . Microbiol.. 1998;29(4):307.
Deng J., Sanchez T., Lalith Q.A-M., Raveendran D., Yunes R.A., Garofalo A., Bolger B.M., Neamati N., . Bioorg. Med. Chem.. 2007;15(14):4985.
Dominguez J.N., Leon C., Rodrigues J., Dominguez N.G., Gut J., Rosenthal P.J., . IL. Farmaco.. 2005;60(4):307.
Horv́ath V., Varga Z., Kov́acs A., . J. Mol. Struct. (Theochem). 2005;755(1-3):247.
Izadyar M., Gholami M.R., . J. Mol. Struct. (Theochem). 2006;759(1-2):11.
Shorter J., . Correlation Analysis in Organic Chemistry; An Introduction to Linear Free Energy Relationships. London: Clarendan Press; 1973.
Kaur D., Sharma P., Bharatam P.V., Dogra N., . J. Mol. Struct. (Theochem). 2006;759(1-3):41.
Krishnakumar V., Ramasamy R., . Indian J. Pure. Appl. Phys.. 2002;40(4):252.
Lahtchev K.L., Batovska D.I., Parushev St.P., Ubiyvock V.M., Sibirny A.A., . Eur. J. Med. Chem.. 2008;43(10):2220.
Laturber P.C., . J. Am. Chem. Soc.. 1961;83(8):1846.
Majinda R.R.T., Abegaz B.M., Bezabih M., Ngadjui B.T., Wanjala C.C.W., Mdee L.L., Bojase G., Sialyo A., Masesane I., Yeboah S.O., . Pure. Appl. Chem.. 2001;73(7):1208.
Mirinda C.L., Aponso G.L., Stevens J.F., Denizer M.L., Buhler D.R., . Cancer Lett.. 2000;149(1-2):21.
Misra S.S., Dinkar, . J. Indian Chem. Soc.. 1972;49(6):639.
Misra S.S., Dinkar, . J. Indian Chem. Soc.. 1972;49(7):725.
Monostory K., Tamasi V., Vereckey L., Perjesi P., . Toxicol.. 2003;184(2–3):203.
Mulliken R.S., . J. Chem. Phys.. 1939;7(2):121.
Nowakowska Z., . Eur. J. Med. Chem. 2007;42(2):125.
Rajendra Prasad Y., Rakikumar P., Jesse Smiles D., Ajay Babu P., . Arkivoc.. 2008;XI:266.
Rao M.A., Nayak A., Rout M.K., . J. Inst. Chem.. 1972;44(pt.5):151.
Senthilkumar K., Sethu Raman M., Kolandaivel P., . J. Mol. Struct. (Theochem). 2006;758(2-3):107.
Sitaram Kumar M., Das J., Iqbal J., Trehan S., . Eur. J. Med. Chem.. 2007;42(4):538.
Sivakumar M., Prabhu Seenivaasan S., Kumar V., Doble M., . Bioorg. Med. Chem. Lett.. 2007;17(10):3169.
Sharma A., Gupta V.P., Virdi A., . Pure. Appl. Phys.. 2002;40(4):246-251.
Solcaniova E., Toma S., . Org. Magn. Reson.. 1980;14(2):138.
Sung D.D., Ananthakrishna Nadar P., . Indian J. Chem.. 2000;39(A11):1066.
Swain C.G., Lupton E.C. Jr., . J. Am. Chem. Soc.. 1968;90(16):4337.
Thirunarayanan G., Ananthakrishna Nadar P., . A. J. Chem.. 2002;14(3-4):1518.
Thirunarayanan G., Ananthakrishna Nadar P., . J. Korean Chem. Soc.. 2006;50(3):183.
Thirunarayanan G., Ananthakrishna Nadar P., . J. Indian Chem. Soc.. 2006;83(11):1107.
Thirunarayanan G., . Indian J. Chem.. 2007;46B(9):1551.
Thirunarayanan G., . J. Korean Chem. Soc.. 2007;51(2):115.
Thirunarayanan G., . J. Indian Chem. Soc.. 2008;84(4):447.
Thirunarayanan G., . J. Korean Chem. Soc.. 2008;52(4):369.
Thirunarayanan G., Surya S., Srinivasan S., Vanangamudi G., Sathiyendiran V., . Spectrochim. Acta.. 2010;75A(1):152.
Thirunarayanan G., Vanangamudi G., Sathiyendiran V., Ravi K., . Indian J. Chem.. 2011;50(4):593.
Vanangamudi G., Thirunarayanan G., . Int. J. Chem. Sci.. 2006;4(4):787.
Wang Y.H., Zou J.W., Zhang B., Lu Y.X., Jin H.X., Yu Q.S., . J. Mol. Struct. (Theochem). 2005;755(1-2):31.
Weber M.W., Hunsaker L.A., Abcouwer S.F., Deck L.M., Vander Jagat D.L., . Bioorg. Med. Chem.. 2005;13(11):3811.

Introduction

Experimental

Synthesis of substituted styryl 2-hydroxy-1-naphthyl ketones

Results and discussion

Infrared spectral study
1H spectral study
13C NMR spectral study

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[1] Arul Kumaran R., Sundararajan R., Vanagamudi G., Subramanian M., Ravi K., Sathiyendiran V., Srinivasan S., Thirunarayanan G., . IUP J. Chem.. 2010;3(1):82.

[2] Dass G.K., . Indian J. Chem.. 2001;40(A1):23.

[3] Deiva C.M., Pappano N.B., Debattista N.B., . Microbiol.. 1998;29(4):307.

[4] Deng J., Sanchez T., Lalith Q.A-M., Raveendran D., Yunes R.A., Garofalo A., Bolger B.M., Neamati N., . Bioorg. Med. Chem.. 2007;15(14):4985.

[5] Dominguez J.N., Leon C., Rodrigues J., Dominguez N.G., Gut J., Rosenthal P.J., . IL. Farmaco.. 2005;60(4):307.

[6] Horv́ath V., Varga Z., Kov́acs A., . J. Mol. Struct. (Theochem). 2005;755(1-3):247.

[7] Izadyar M., Gholami M.R., . J. Mol. Struct. (Theochem). 2006;759(1-2):11.

[8] Shorter J., . Correlation Analysis in Organic Chemistry; An Introduction to Linear Free Energy Relationships. London: Clarendan Press; 1973.

[9] Kaur D., Sharma P., Bharatam P.V., Dogra N., . J. Mol. Struct. (Theochem). 2006;759(1-3):41.

[10] Krishnakumar V., Ramasamy R., . Indian J. Pure. Appl. Phys.. 2002;40(4):252.

[11] Lahtchev K.L., Batovska D.I., Parushev St.P., Ubiyvock V.M., Sibirny A.A., . Eur. J. Med. Chem.. 2008;43(10):2220.

[12] Laturber P.C., . J. Am. Chem. Soc.. 1961;83(8):1846.

[13] Majinda R.R.T., Abegaz B.M., Bezabih M., Ngadjui B.T., Wanjala C.C.W., Mdee L.L., Bojase G., Sialyo A., Masesane I., Yeboah S.O., . Pure. Appl. Chem.. 2001;73(7):1208.

[14] Mirinda C.L., Aponso G.L., Stevens J.F., Denizer M.L., Buhler D.R., . Cancer Lett.. 2000;149(1-2):21.

[15] Misra S.S., Dinkar, . J. Indian Chem. Soc.. 1972;49(6):639.

[16] Misra S.S., Dinkar, . J. Indian Chem. Soc.. 1972;49(7):725.

[17] Monostory K., Tamasi V., Vereckey L., Perjesi P., . Toxicol.. 2003;184(2–3):203.

[18] Mulliken R.S., . J. Chem. Phys.. 1939;7(2):121.

[19] Nowakowska Z., . Eur. J. Med. Chem. 2007;42(2):125.

[20] Rajendra Prasad Y., Rakikumar P., Jesse Smiles D., Ajay Babu P., . Arkivoc.. 2008;XI:266.

[21] Rao M.A., Nayak A., Rout M.K., . J. Inst. Chem.. 1972;44(pt.5):151.

[22] Senthilkumar K., Sethu Raman M., Kolandaivel P., . J. Mol. Struct. (Theochem). 2006;758(2-3):107.

[23] Sitaram Kumar M., Das J., Iqbal J., Trehan S., . Eur. J. Med. Chem.. 2007;42(4):538.

[24] Sivakumar M., Prabhu Seenivaasan S., Kumar V., Doble M., . Bioorg. Med. Chem. Lett.. 2007;17(10):3169.

[25] Sharma A., Gupta V.P., Virdi A., . Pure. Appl. Phys.. 2002;40(4):246-251.

[26] Solcaniova E., Toma S., . Org. Magn. Reson.. 1980;14(2):138.

[27] Sung D.D., Ananthakrishna Nadar P., . Indian J. Chem.. 2000;39(A11):1066.

[28] Swain C.G., Lupton E.C. Jr., . J. Am. Chem. Soc.. 1968;90(16):4337.

[29] Thirunarayanan G., Ananthakrishna Nadar P., . A. J. Chem.. 2002;14(3-4):1518.

[30] Thirunarayanan G., Ananthakrishna Nadar P., . J. Korean Chem. Soc.. 2006;50(3):183.

[31] Thirunarayanan G., Ananthakrishna Nadar P., . J. Indian Chem. Soc.. 2006;83(11):1107.

[32] Thirunarayanan G., . Indian J. Chem.. 2007;46B(9):1551.

[33] Thirunarayanan G., . J. Korean Chem. Soc.. 2007;51(2):115.

[34] Thirunarayanan G., . J. Indian Chem. Soc.. 2008;84(4):447.

[35] Thirunarayanan G., . J. Korean Chem. Soc.. 2008;52(4):369.

[36] Thirunarayanan G., Surya S., Srinivasan S., Vanangamudi G., Sathiyendiran V., . Spectrochim. Acta.. 2010;75A(1):152.

[37] Thirunarayanan G., Vanangamudi G., Sathiyendiran V., Ravi K., . Indian J. Chem.. 2011;50(4):593.

[38] Vanangamudi G., Thirunarayanan G., . Int. J. Chem. Sci.. 2006;4(4):787.

[39] Wang Y.H., Zou J.W., Zhang B., Lu Y.X., Jin H.X., Yu Q.S., . J. Mol. Struct. (Theochem). 2005;755(1-2):31.

[40] Weber M.W., Hunsaker L.A., Abcouwer S.F., Deck L.M., Vander Jagat D.L., . Bioorg. Med. Chem.. 2005;13(11):3811.

IR and NMR spectral studies of some 2-hydroxy-1-naphthyl chalcones: Assessment of substituent effects

Abstract

Keywords

Styryl 2-hydroxy-1-naphthyl ketones

IR and NMR spectra

Hammett substituent constants

Correlation analysis

1 Introduction

2 Experimental

2.1 Synthesis of substituted styryl 2-hydroxy-1-naphthyl ketones

3 Results and discussion

3.1 Infrared spectral study

3.2 1H spectral study

3.3 13C NMR spectral study

Acknowledgement

References

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3.2 ¹H spectral study

3.3 ¹³C NMR spectral study