Scholarly article on topic 'In vitro microbial studies of new pyrazolyl quinazolin-4(3H) ones'

In vitro microbial studies of new pyrazolyl quinazolin-4(3H) ones Academic research paper on "Chemical sciences"

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{Quinazoline / Pyrazole / Chalcone / "Antimicrobial activity"}

Abstract of research paper on Chemical sciences, author of scientific article — N.B. Patel, G.G. Barat

Abstract A series of new 2-[2-(2,6-dichlorophenyl)amino]phenyl methyl-3-[(5-substituted phenyl)-1,5-dihydro-1H-pyrazol-3-yl-amino]-6-iodoquinazolin-4(3H) ones (6a–m) have been synthesized by the reaction of 2-[2-(2,6-dichlorophenyl)amino]phenyl methyl-3-substituted phenyl acryl amido-6-iodoquinazolin-4(3H) ones with hydrazine hydrate in the presence of glacial acetic acid. The chalcone (5a–m) have been prepared by the condensation of 2-[2-(2,6-dichlorophenyl)amino]phenyl methyl-3-acetamido-6-iodoquinazolin-4(3H) one with different substituted aromatic aldehyde. The compound 1 on treatment with 5-iodoanthranilic acid in pyridine undergoes cyclisation gave 2-[2-(2,6-dichlorophenyl)amino]phenyl methyl-6-iodo-3,1-benzoxazin-4(3H) one (2). Treatment on benzoxazine with hydrazine hydrate gave 3-amino-2-[2-(2,6-dichlorophenyl)amino]phenyl methyl-6,8-dibromo quinazolin-4(3H) one (3) followed by acetylation synthesized 2-[2-(2,6-dichlorophenyl)amino]phenyl methyl-3-acetamido-6,8-dibromoquinazolin-4(3H)-one (4). The structure of synthesized compounds has been elucidated by IR, 1H NMR, 13C NMR and elemental analysis. The products were screened for antibacterial and antifungal activity. Among the series containing some of the compounds showed promising results against standard drugs.

Academic research paper on topic "In vitro microbial studies of new pyrazolyl quinazolin-4(3H) ones"

King Saud University Journal of Saudi Chemical Society

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ORIGINAL ARTICLES

In vitro microbial studies of new pyrazolyl quinazolin-4(3H) ones

N.B. Patel a *, G.G. Barat b

a Department of Chemistry, Veer Narmad South Gujarat University, Surat 395 007, India b Department of Chemistry, Art's, Science and Commerce College, Pilvai, N.G. 382 850, India

Received 8 June 2009; accepted 10 November 2009 Available online 4 February 2010

KEYWORDS

Quinazoline;

Pyrazole;

Chalcone;

Antimicrobial activity

Abstract A series of new 2-[2-(2,6-dichlorophenyl)amino]phenyl methyl-3-[(5-substituted phenyl)-1,5-dihydro-1H-pyrazol-3-yl-amino]-6-iodoquinazolin-4(3H) ones (6a-m) have been synthesized by the reaction of 2-[2-(2,6-dichlorophenyl)amino]phenyl methyl-3-substituted phenyl acryl amido-6-iodoquinazolin-4(3H) ones with hydrazine hydrate in the presence of glacial acetic acid. The chalcone (5a-m) have been prepared by the condensation of 2-[2-(2,6-dichlorophenyl)amino]phenyl methyl-3-acetamido-6-iodoquinazolin-4(3H) one with different substituted aromatic aldehyde. The compound 1 on treatment with 5-iodoanthranilic acid in pyridine undergoes cyclisation gave 2-[2-(2,6-dichlorophenyl)amino]phenyl methyl-6-iodo-3,1-benzoxazin-4(3H) one (2). Treatment on benzoxazine with hydrazine hydrate gave 3-amino-2-[2-(2,6-dichlorophenyl)amino]phenyl methyl-6,8-dibromo quinazolin-4(3H) one (3) followed by acetylation synthesized 2-[2-(2,6-dichloro-phenyl)amino]phenyl methyl-3-acetamido-6,8-dibromoquinazolin-4(3H)-one (4). The structure of synthesized compounds has been elucidated by IR, 1H NMR, 13C NMR and elemental analysis. The products were screened for antibacterial and antifungal activity. Among the series containing some of the compounds showed promising results against standard drugs.

© 2010 King Saud University. All rights reserved.

1. Introduction

* Corresponding author.

E-mail addresses: drnavin@satyam.net.in (N.B. Patel), gamanbarat@ gmail.com (G.G. Barat).

1319-6103 © 2010 King Saud University. All rights reserved. Peerreview under responsibility of King Saud University. doi:10.1016/j.jscs.2010.02.016

The heterocyclic systems encompassing pyrazolines are explored to the maximum extent owing to their wide spectrum of pharmacological activities, such as, anti-inflammatory agent (Nesrin et al., 2007), antifungal (Bekhit and Fahmy, 2003), antibacterial (Bahekar and Rao, 2000), analgesics (Gursoy et al., 1990), COX-2 inhibitor (Norris et al., 2005), antiandro-genic (Zhang et al., 2007), anti parasitic (Kuettell et al., 2007). 6-Halo and 6,8-dihalo derivatives of quinazolinone possess potential antihyper lipidemic activity (Refaie and Esmat, 2005). Recently, the several scientists elucidated that quinazoli-none system possess variable sites at position 2 and 3 which

Pyridine 0-5 °C

nh2nh2 h2o

Absolute ethanol Refluxed, 6-8 h

N—NH2

Scheme 1

can be suitably modified by the introduction of different heterocyclic moieties viz. pyrazol, oxazole to yield the potential anticonvulsant agents, furthermore a large number of pyrazo-line derivatives were found to possess anticonvulsant activity (Soni et al., 1987; Tripathi et al., 1980). In order to see the effect of incorporation of pyrazoline moiety in quanazoline nucleus at position-3 on convulsions produced by maximal electro sock in albino rats. Keeping this observation in view we have synthesized a new series of pyrazolyl quinazolinone.

The starting compound 2-[2-(2,6-dichlorophenyl)amino]-phenyl acetyl chloride (1) has been prepared from starting material 2-[2-(2,6-dichlorophenyl)amino]phenyl acetic acid by reacting with thionyl chloride, which on treatment with 5-iodo anthranilic acid gave 2-[2-(2,6-dichlorophenyl)amino]phenyl methyl-6-iodo-3,1-benzoxazin-4(3H) one (2). The reaction of 2 with hydrazine hydrate refluxing in absolute ethanol led to 3-amino-2-[2-(2,6-dichlorophenyl)amino]phenyl methyl-6,8-di-bromo quinazolin-4(3H) one (3). The reaction of 3 with acetyl chloride undergoes acetylation yeilds 2-[2-(2,6-dichloro-phenyl)amino]phenyl methyl-3-acetamido-6,8-dibromoquinaz-olin-4(3H)-one (4), which on condensation with aromatic

aldehyde in presence of base-catalyst yielded 2-[2-(2,6-dichlo-rophenyl)amino]phenyl methyl-3-substituted phenyl acryl amido-6-iodoquinazolin-4(3H) ones (5a-m), subsequently cyclisation undergoes refluxing with hydrazine yields 2-[2-(2,6-dichlorophenyl)amino]phenyl methyl-3-[(5-substituted phenyl)-1,5-dihydro-1H-pyrazol-3-yl-amino]-6-iodoquinazo-lin-4(3H) ones (6a-m), respectively (Scheme 1).

2. Experimental

All the reactions were monitored by employing TLC technique using appropriate solvent system for development. Melting points of all synthesized compounds were determined in open capillaries and are uncorrected. IR spectra (KBr) were recorded on Perkin-Elmer 1300 FTIR spectrophotometer. *H NMR and 13C NMR spectra were recorded in CDCl3 using TMS as internal standard on a Bruker spectrometer at 400 and 75 MHz, respectively. Analytical data of C, H, N were within 0.04% of the theoretical values. The starting compound 2 were prepared according to the reported method10.

Dry benzene 0-5 °C

Absolute ethanol

2% NaOH Refluxed, 10-12 h

nh2nh2 h2o

2-3 drops of CH3COOH 8-10 h

R = a = H

b = 2-OH c = 3-OH d = 4-OH

e = 2-Cl i = 3-NO2

f = 3-Cl j = 4-NO2

g = 4-Cl k = 4-N(CH3)2

h = 2-NO2 l = 2-OCH3

m = 4-OCH3

Scheme 1 (continued)

2.1. 2-[2-(2,6-Dichlorophenyl)amino]phenyl methyl-6-iodo-3,1-benzoxazin-4(3H) one (2)

To the solution of 2-[(2,6-dichlorophenyl)amino]phenyl acetyl chloride (3.14 g, 0.01 mol) in pyridine (25 ml) kept on an ice

bath at 0-5 0C. Added each small portion of 5-iodo anthranilic acid (2.53 g, 0.01 mol) in pyridine were stirred for 1 h to maintain temperature 0-5 oc. After the addition, reaction mixture was stirred further 1 h at room temperature. A pasty mass thus obtained was washed thoroughly with sodium bicarbonate

CHCOCl

Table 1 Physical and analytical characterization data of compound 6a-m.

Compound no. R Molecular formula M.P (°C) Yield (%) Elemental analysis%

C H N

Calcd. Found Calcd. Found Calcd. Found

6a H C3oH23ON6ICl2 119-123 68 52.87 52.86 3.37 3.36 12.33 12.35

6b 2-OH C30H23O2N6lCl2 161-163 62 51.65 51.66 3.29 3.28 12.o5 12.o6

6c 3-OH C30H23O2N6lCl2 173-175 67 51.65 51.67 3.29 3.3o 12.o5 12.o6

6d 4-OH C30H23O2N6lCl2 187-189 63 51.65 51.66 3.29 3.3o 12.o5 12.o7

6e 2-Cl C3oH22ON6lCl3 129-131 69 5o.32 5o.33 3.o7 3.o8 11.74 11.75

6f 3-Cl C3oH22ON6lCl3 143-145 67 5o.32 5o.32 3.o7 3.1o 11.74 11.76

6g 4-Cl C30H22ON6ICl3 159-161 73 5o.32 5o.33 3.o7 3.o7 11.74 11.77

6h 2-NO2 C3oH22O3N7ICl2 178-179 69 49.59 49.58 3.o3 3.o4 13.49 13.51

6i 3-NO2 C3oH22O3N7ICl2 191-193 71 49.59 49.6o 3.o3 3.o5 13.49 13.51

6j 4-NO2 C3oH22O3N7ICl2 2o3-2o5 63 49.59 49.59 3.o3 3.o4 13.49 13.5o

6k 4-N(CH3)2 C32H28ON7lCl2 153-155 7o 53.o4 53.o6 3.86 3.87 13.53 13.55

61 2-OCH3 C31H25O2N6ICl2 141-143 63 52.32 52.33 3.51 3.52 11.81 11.82

6m 4-OCH3 C31H25O2N6ICl2 161-163 69 52.32 52.34 3.51 3.53 11.81 11.83

Table 2 Spectral data of compounds 6a-m.

Compound no.

IR cm"1 (KBr)

1H NMR (d, CDCl3)

3C NMR (d, CDCl3)

3379(N-H str), 3055, 2855(C-H str), 1724(C=O), 1609(C=N), 1320(C-Nstr), 784(C-Cl), 506(C-I)

3541(O-H str), 3401(N-H str), 3071, 2856(C-H str), 172(C=O), 1614(C=N), 1319(C-N str), 771(C-Cl), 511(C-I)

3538(O-H str), 3396(N-H str), 3068, 2869(C-H str), 1731 (C=O), 1614(C=N), 1319(C-N str), 779 (C-Cl), 506(C-I)

3543(O-H str), 3389(N-H str), 3057, 2862(C-H str), 1727(C=O), 1613(C=N), 1319(C-N str), 781(C-Cl), 516(C-I)

3369(N-Hstr), 3063, 2857 (C-H str), 1715(C=O), 1614(C=N), 1321(C-Nstr), 781(C-Cl), 502(CI)

3379(N-H str), 3057, 2867 (C-H str), 1717(C=O), 1611(C=N), 1322(C-Nstr), 783(C-Cl), 511 (C-I)

3398(N-H str), 3062, 2861(C-H str), 1714(C=O), 1615(C=N), 1317(C-N str), 781(C-Cl), 510 (C-I)

3370(N-H str), 3068, 2869 (C-H str), 1728(C=O), 1613(C=N), 1565, 1361 (-NO2), 1315(C-N str), 781(C-Cl), 509(C-I)

3377(N-H str), 3069, 2857 (C-H str), 1731(C=O), 1614.59(C=N), 1564, 1359 (-NO2), 1316(C-N str), 778(C-Cl), 503(C-I)

3371(N-H str), 3061, 2860 (C-H str), 1731(C=O), 1615(C=N), 1563, 1361 (-NO2), 1317(C-N str), 775(C-Cl), 507(C-I)

3366(N-H str), 3062, 2867 (C-H str), 1720(C=O), 1617(C=N), 1320(C-N str), 773(C-Cl), 511 (C-I)

3389(N-H str), 3057, 2862 (C-H str), 1724(C=O), 1613(C=N), 1319(C-N str), 1240, 1106C-Ö-C), 781(C-Cl), 511(C-I)

3386(N-H str), 3053, 2846(C-H str), 1722(C=O), 1617(C=N), 1322(C-N str), 1238, 1103(C-O-C), 779(C-Cl), 510(C-I)

9.77(s, 1H, NH), 2.15(d, 1H, =N-NH), 8.17(s, 1H, -N-NH), 3.65(s, 2H, CH2), 3.05(d, 1Ha), 3.56(d, 1Hb), 6.47(t, 1Hx), 6.47-7.96(m, 15H, Ar-H)

9.78(s, 1H, -NH), 2.13(d, 1H, =N-NH), 8.19(s, 1H, -N-NH), 3.63(s, 2H, -CH2), 3.07(d, 1Ha), 3.56(d, 1Hb), 6.48(t, 1Hx), 6.47-7.91(m, 14H, Ar-H), 10.27(s, 1H, -OH)

9.78(s, 1H, -NH), 2.19(d, 1H, =N-NH), 8.21(s, 1H, -N-NH), 3.65(s, 2H, -CH2), 3.06(d, 1Ha), 3.46(d, 1Hb), 6.49(t, 1Hx), 6.45-7.91(m, 14H, Ar-H), 10.28(s, 1H, -OH)

9.78(s, 1H, -NH), 2.18(d, 1H, =N-NH), 8.18(s, 1H, -N-NH), 3.61(s, 2H, -CH2), 3.05(d, 1Ha), 3.45(d, 1Hb), 6.47(t, 1Hx), 6.43-7.96(m, 14H, Ar-H), 10.25(s, 1H, -OH)

9.78(s, 1H, -NH), 2.17(d, 1H, =N-NH), 8.19(s, 1H, -N-NH), 3.63(s, 2H, -CH2), 3.06(d, 1Ha), 3.49(d, 1Hb), 6.57(t, 1Hx), 6.43-7.96 (m, 14H, Ar-H).

9.79(s, 1H, -NH), 2.18(d, 1H, =N-NH), 8.17(s, 1H, -N-NH), 3.65(s, 2H, -CH2), 3.05(d, 1Ha), 3.48(d, 1Hb), 6.49(t, 1Hx), 6.43-7.93(m, 14H, Ar-H).

9.77(s, 1H, -NH), 2.15(d, 1H, =N-NH), 8.17(s, 1H, -N-NH), 3.65(s, 2H, -CH2), 3.07(d, 1Ha), 3.47(d, 1Hb), 6.49(t, 1Hx), 6.43-7.96(m, 14H, Ar-H).

9.78(s,1H, -NH), 2.17(d, 1H, =N-NH), 8.20(s, 1H, -N-NH), 3.62(s, 2H, -CH2), 3.06(d, 1Ha), 3.48(d, 1Hb), 6.49(t, 1Hx),

6.43-7.94(m, 14H, Ar-H)

9.79(s, 1H, -NH), 2.16(d, 1H, =N-NH), 8.17(s, 1H, -N-NH), 3.63(s, 2H, -CH2), 3.05(d, 1Ha), 3.48(d, 1Hb), 6.49(t, 1Hx),

6.44-7.95(m, 14H, Ar-H)

9.77(s, 1H, -NH), 2.18(d, 1H, =N-NH), 8.21(s, 1H, -N-NH), 3.65(s, 2H, -CH2), 3.07(d, 1Ha), 3.46(d, 1Hb), 6.51(t, 1Hx),

6.43-7.96(m, 14H, Ar-H)

9.78(s, 1H, -NH), 2.15(d, 1H, =N-NH), 8.18(s, 1H, -N-NH), 3.62(s, 2H, -CH2), 3.06(d, 1Ha), 3.48(d, 1Hb), 6.57(t, 1Hx),

6.44-7.95 (m, 14H, Ar-H), 2.83(s, 6H, -CH3)

9.79(s, 1H, -NH), 2.16(d, 1H, =N-NH), 8.21(s, 1H, -N-NH), 3.62(s, 2H, -CH2), 3.08(d, 1Ha), 3.48(d, 1Hb), 6.59(t, 1Hx),

6.45-7.96 (m, 14H, Ar-H), 3.80(s, 3H, -OCH3)

9.77(s, 1H, -NH), 2.17(d, 1H, =N-NH), 8.22(s, 1H, -N-NH), 3.63(s, 2H, -CH2), 3.06(d, 1Ha), 3.46(d, 1Hb), 6.57(t, 1Hx), 6.43-7.95(m, 14H, Ar-H), 3.81(s, 3H, -OCH3)

30.51(-CH2), 35.73, 40.23, 161.13(pyrazol-C), 162.30C=O), 173.6(immine aromatic-C), 124.0-129.4 (aromatic-24C)

31.3(-CH2), 39.4, 44.6, 161.1(pyrazol-C), 162.2(^C=O), 173.2(immine aromatic-C), 124.1-130.2(aromatic-24C)

31.5(-CH2), 39.5, 44.9, 161.3(pyrazol-C), 162.3(^C=O), 173.1(immine aromatic-C), 123.1-130.1(aromatic-24C)

30.62(-CH2), 39.5, 42.4, 161.2(pyrazol-C), 162.1(^C=O), 172.7(immine aromatic-C), 124.1-129.1(aromatic-24C)

30.6(-CH2), 35.7, 41.5, 161.2 (pyrazol-C), 162.3(^C=O), 171.7(immine aromatic-C), 124.1-129.7(aromatic-24C)

31.3(-CH2), 37.5, 42.1, 161.3 (pyrazol-C), 162.1(^C=O), 173.1(immine aromatic-C), 124.0-130.3(aromatic-24C)

29.6(-CH2), 35.6, 41.7, 161.2 (pyrazol-C), 162.1(^C=O), 172.3 (immine aromatic-C), 124.0-130.0(aromatic-24C)

30.5(-CH2), 36.5, 41.2, 161.0 (pyrazol-C), 162.3£C=O), 172.4 (immine aromatic-C), 124.3-129.7(aromatic-24C)

31.4(-CH2), 37.2, 41.6, 161.2 (pyrazol-C), 162.1(^C=O), 173.1 (immine aromatic-C), 124.2-129.8(aromatic-24C)

30.6(-CH2), 36.1, 42.7, 161.2 (pyrazol-C), 162.1(^C=O), 172.8 (immine aromatic-C), 124.0-129.9(aromatic-24C)

30.5(-CH2), 38.2, 46.6, 155 (pyrazol-C), 160.3£C=O), 164 (immine aromatic-C), 47.1(N-CH3), 124.1-130.1 (aromatic-24C)

31.2(-CH2), 36.8, 40.7, 161.8 (pyrazol-C), 162.3(^C=O), 173.1(immine aromatic-C), 58.4(O-CH3), 124.2-130.1 (aromatic-24C)

30.2(-CH2), 365, 41.6, 161.3 (pyrazol-C), 162.2(^C=O), 172.8 (immine aromatic-C), 59.2(-OCH3), 124.1-129.6 (aromatic-24C)

(5%) to remove unreacted acid. A solid separated was filtered, dried and recrystallised from methanol. M.P.: 167-169 oC; Yield: 67%. IR(KBr): 3414(NH), 3071, 2883(C-H), 1721(C=O), 1613(C=N), 1325(C-N), 1236(C-O-c), 749(NH wag), 780(C-Cl), 511(C-I).

2.2. 3-Amino 2-[2-(2,6-dichlorophenyl)amino]phenyl methyl-6-iodoquinazolin-4(3H) one (3)

To a mixture of 2-[2-(2,6-dichlorophenyl)amino]phenyl methyl-6-iodo-3,1-benzoxazine-4(H) one (5.23 g, 0.01 mol) and hydrazine (99%) (0.50 g, 0.01 mol) in 25.0 ml pyridine was refluxed at 180-200 oC in an oil bath for 5-6 h. After completion of the reaction, the oily mass was slowly poured onto crushed acidic (HCl, 25 ml) ice cold water with occasionally stirring. The solid thus obtained was filtered and washed several times with water. The crushed product was dried and recrystallized from ethanol. M.P.: 132-134 oC; Yield: 71%.

Elemental analysis: % C = 47.21(47.19), %H = 2.83(2.80), %N = 10.54(10.48).

IR(KBr): 3468, 3403(NH2), 3367(NH), 3068, 2861(C-H), 1719(C=O), 1613(C=N), 1315(C-N), 778(C-Cl), 505(C-I).

1H NMR(CDCl3): 9.78(s, 1H, -NH-), 2.1(s, 2H, -N-NH2), 6.34-7.92(m, 10H, Ar-H), 3.65(s, 2H, -CH2).

2.3. 2-[2-(2,6-Dichlorophenyl)amino]phenyl methyl-3-acetamido-6-iodo quinazolin-4(3H) one (4)

To a solution of 3-amino 2-[2-(2,6-dichlorophenyl)amino]-phenyl methyl-6-iodoquinazolin-4(3H) one (5.37 g, 0.01 mol) in drybenzene (50 ml), acetyl chloride (0.785 g, 0.01 mol) was added drop by drop at 0-5 oC over the period of 1 h with continuous stirring. After completion of the addition, the reaction mixture kept over night. The excess of solvent was distilled off under reduced pressure and then poured into ice cold water and shake well, the solid thus obtained was filtered and recrys-tallized from methanol. M.P.: 181-183 oC; Yield: 71%.

Elemental analysis: %C = 47.70(47.66), %H = 2.96(2.93), %N = 9.71(9.67).

IR(KBr): 3404(NH), 3063, 2852(C-H), 1723(C=O), 1614(C=O of -COCH3), 1314(C-N), 781(C-Cl), 507(C-I).

1H NMR(CDCl3): 9.77(s, 1H, -NH-), 8.36(s, 1H, -N-NH-), 6.34-7.91(m, 10H, Ar-H), 2.69(s, 3H, -CH3), 3.64(s, 2H, -CH2).

2.4. 2-[2-(2,6-Dichlorophenyl)amino]phenyl methyl-3-(phenyl acryl amido)-6-iodo quinazolin-4(3H) one (5a)

To a solution of2-[2-(2,6-dichlorophenyl)amino]phenyl methyl-3-acetamido-6-iodo quinazolin-4(3H) one (5.79 g, 0.01 mol) in absolute ethanol (50 ml) and add substituted aromatic aldehyde (0.01 mol) in 2% NaOH was refluxed for 10-12 h cooled and poured into ice cold water. The solid thus obtained was filtered, washed with water and recrystallized from methanol.

Elemental analysis: %C = 53.99(53.97), %H = 3.21(3.14), %N = 8.45 (8.39).

IR(KBr): 3413(NH), 3061, 2859(C-H), 1723(C=O), 1649(C=O of -COCH3), 1580 (CH=CH), 1318(C-N), 779(C-Cl), 509(C-I).

1H NMR(CDCl3): 9.79(s, 1H, -NH-), 8.18(s, 1H, -N-NH), 6.47-7.96(m, 15H, Ar-H), 3.62 (s, 2H, -CH2), 6.81(d, 1H, COCH=), 8.61(d, 1H, =CH-Ar).

The remaining 5b-m compounds were prepared by the above mention similar method.

2.5. 2-[2-(2,6-Dichlorophenyl)amino]phenyl methyl-3-(5-phenyl-1,5-dihydro-1H-pyrazol-3-yl amino)-6-iodo quinazolin-4(3H) one (6a)

To a solution of 2-[2-(2,6-dichlorophenyl)amino]phenyl methyl-3-(phenyl acryl amido)-6-iodo quinazolin-4(3H)-one (6.67 gm, 0.01 mol) in methanol (25 ml), added hydrazine hydrate (99%) (1.0 g, 0.02 mol) and few drops of glacial acetic acid. The reaction mixture was refluxed for 8-10 h on a water bath and cooled. The separated solid was filtered, washed with water and recrystallized from methanol.

IR(KBr): 3379(N-H), 3055, 2855(C-H), 1724(C=O), 1609(C=N), 1320(C-N), 784(C-Cl), 506(C-I).

1H NMR(CDCl3): 9.77(s, 1H, -NH), 2.15(d, 1H, =N-NH), 8.17(s, 1H, -N-NH), 3.65(s, 2H, -CH2), 3.05(d, 1Ha), 3.56(d, 1Hb), 6.47(t, 1Hx), 6.47-7.96(m, 15H, Ar-H).

13C NMR: 30.51(-CH2), 35.73, 40.23, 161.13(immine pyra-zol-C), 162.3(^C=O), 173.6(immine aromatic-C), 124.0,

142.3, 103.9, 136.2, 122.4, 145.9, 113.5, 129.6, 117.2, 126.6, 113.5, 143.8, 127.9, 129.9, 118.2, 126.7, 119.0, 138.0, 135.3,

129.4, 127.8, 121.8, 127.8, 129.4 aromatic-C.

The remaining 6b-m compounds were prepared by the above mention similar method. The characterization data and spectral data of 6a-m are recorded in Tables 1 and 2.

3. Result and discussion

In the present work, an attempt has been made to undertake the synthesis of pyrazolyl quinazolin-4(3H) ones 6a-m via corresponding chalcones 5a-m through a multi step process. For this purpose, the required benzoxazine 2 was prepared by cyclisation reaction between 2-[2-(2,6-dichlorophenyl)-amino]phenyl acetyl chloride 1 and 5-iodo anthranilic acid using pyridine as a solvent. Formation of product was confirmed by a sharp band at 1721 cm-1 for C=O group along with a peak at 1236 cm-1 for C-O-C stretching in IR spectra. Also a broad band at 3434 cm-1 and C-N stretching at 1325 cm-1 indicates the presence of secondary amine. Singlet at 9.79 d ppm equivalent to one proton indicated the presence of secondary amine. Asymmetrical and symmetrical C-H stretching vibration at 3071 cm-1 and 2883 cm-1 confirmed the presence of methylene group, which was further confirmed by the appearance of singlet equivalent to two protons at 9.78 d ppm. Benzoxazine 2 was converted to quinazolin-4(3H) one 3 by the reaction with hydrazine hydrate. Insertion of the nitrogen in the ring was characterized by disappearance of band at cm-1 of C-O-C and shift of car-bonyl band from 1721 cm-1 to 1719 cm ; which was characterized by the appearance of asymmetrical and symmetrical stretching vibration of-NH2 group at 3467 cm-1 and 3403 cm -1, respectively and was further confirmed by the appearance of singlet equivalent to two protons at 2.1 d ppm. When 3 was treated with acetyl chloride yielded acetamido quinazolin-4(3H) one 4 and was characterized by the disappearance of asymmetrical and symmetrical stretching vibration of -NH2 group at 3467 cm-1 and 3403 cm-1, respectively. The stretching vibration band appeared at 1614 cm-1 due to C=O of-COCH3. The reaction 4 with aromatic aldehyde yields chalcone 5a-m. Which was confirmed by the disappearance of stretching vibra-

tion band at 1614 cm-1 due to C=O of-COCH3, and stretching vibration band at 1580 cm-1 due to the (CH=CH) of chalcone and was further confirmed by the appearance of singlet equivalent to one proton at 6.8 d ppm and 8.6 d ppm, respectively. The reaction of 5a-m with hydrazine hydrate desired product 6a-m were obtained. The products were confirmed by spectral data (Archna et al., 2002; Propsavin et al., 2000).

IR spectrum of 6a-m, -NH absorption appeared as a broad band in the region of 3450-3350 cm-1, aromatic C-H stretching vibrations were observed in the region of 3030-2820 cm-1, C=O group of quinazolinone appeared in the range of 17501700 cm-1, 1630-1600 cm-1 due to ^C=N, C-N stretching vibrations were observed in the region of 1570-1550(sym)

and 1365-1350(asym) cm-1, C-O-C at 1250-1100 cm-1; at 750-650 cm-1 and ~500 cm-1 due to C-Cl and C-I stretching, respectively.

The 1H NMR spectra of 6a-m exhibit a characteristic ABX pattern for the presence of two distreotopic pro-tons(non-equivalent) at C-4 and one proton at the C-5 position (Pathak et al., 2008). These protons appeared as three doublets of doublets. They showed double doublet from d 3.02-3.15 (due to a -CH at C-4); d 3.35-3.45 (due to fi-Cff at C-4) and d 6.50-6.75 (due to -H at C-5), each intercepting for one proton. The aromatic resonance signal appeared as a multiplet from d 6.34-8.1, singlet due to >NH protons at d 9.4-9.9, singlet due to -CH2 protons appeared at d 3.60-3.65;

Table 3 Gram positive antibacterial activity of compounds 6a-m.

Compound R S. aureus

Std: Penicillin

Uh UL SH SL

6a H 16 13 30 25

6b 2-OH 11 09 30 25

6c 3-OH 08 06 30 25

6d 4-OH 09 07 30 25

6e 2-Cl 09 07 30 25

6f 3-Cl 07 0 30 25

6g 4-Cl 07 0 30 25

6h 2-NO2 14 12 30 25

6i 3-NO2 13 11 30 25

6j 4-NO2 14 12 30 25

6k 4-N(CH3>2 09 07 30 25

61 2-OCH3 10 08 30 25

6m 4-OCH3 10 08 30 25

SH, zone of inhibition of Standard at concentration 100 lg/ml. SL, zone of inhibition of Standard at concentration 50 lg/ml. UH, zone of inhibition of unknown at concentration 100 lg/ml. UL, zone of inhibition of unknown at concentration 50 lg/ml.

Potency % B. subtilis Potency %

Std: Penicillin

Uh Ul Sh Sl

55.29 16 13 27 21 58.89

40.18 12 10 27 21 44.26

34.37 10 08 27 21 39.04

36.20 10 08 27 21 39.04

36.20 08 06 27 21 34.45

0 07 0 27 21 0

0 07 0 27 21 0

46.97 13 11 27 21 47.13

44.59 12 10 27 21 44.26

46.97 12 10 27 21 44.26

36.20 09 07 27 21 36.67

38.14 11 09 27 21 41.58

38.14 10 08 27 21 39.04

Table 4 Gram negative antibacterial activity of compounds 6a-m.

Compound R E. coli

Std: Penicillin

Uh Ul SH Sl

6a H 06 0 31 25

6b 2-OH 11 09 31 25

6c 3-OH 13 11 31 25

6d 4-OH 11 09 31 25

6e 2-Cl 10 08 31 25

6f 3-Cl 07 0 31 25

6g 4-Cl 07 0 31 25

6h 2-NO2 15 13 31 25

6i 3-NO2 20 17 31 25

6j 4-NO2 14 12 31 25

6k 4-N(CH3>2 06 0 31 25

61 2-OCH3 15 13 31 25

6m 4-OCH3 16 13 31 25

SH, zone of inhibition of Standard at concentration 100 lg/ml. SL, zone of inhibition of Standard at concentration 50 lg/ml. UH, zone of inhibition of unknown at concentration 100 lg/ml. UL, zone of inhibition of unknown at concentration 50 lg/ml.

Potency % Certium Potency %

Std: Penicillin

Uh Ul Sh Sl

0 06 0 28 23 0

38.01 10 08 28 23 39.66

42.31 12 10 28 23 44.36

38.01 12 10 28 23 44.36

35.99 11 09 28 23 41.94

0 06 0 28 23 0

0 06 0 28 23 0

47.11 14 12 28 23 49.63

63.51 18 15 28 23 64.31

44.64 13 11 28 23 46.91

0 06 0 28 23 0

47.11 14 12 28 23 49.63

52.46 15 13 28 23 52.48

Table 5 Fungicidal activity of compounds 6a-m.

Compound R A. niger Potency % C. albicans Potency %

Std: Fluconazole Std: Fluconazole

Uh UL SH SL Uh Ul Sh Sl

6a H 13 10 28 22 45.75 13 11 26 21 49.60

6b 2-OH 11 09 28 22 40.53 12 10 26 21 46.68

6c 3-OH 08 06 28 22 33.87 09 07 26 21 38.86

6d 4-OH 10 08 28 22 38.19 11 09 26 21 43.89

6e 2-Cl 15 12 28 22 54.08 16 13 26 21 61.86

6f 3-Cl 11 09 28 22 40.53 12 10 26 21 46.68

6g 4-Cl 14 12 28 22 48.59 15 12 26 21 54.34

6h 2-NO2 13 10 28 22 45.75 14 12 26 21 52.71

6i 3-NO2 09 07 28 22 35.96 10 08 26 21 41.30

6j 4-NO2 11 09 28 22 40.53 12 10 26 21 46.68

6k 4-N(CH3)2 13 10 28 22 45.75 14 12 26 21 52.71

61 2-OCH3 06 0 28 22 0 07 0 26 21 0

6m 4-OCH3 06 0 28 22 0 07 0 26 21 0

SH, zone of Inhibition of Standard at concentration 20 lg/ml. SL, zone of inhibition of Standard at concentration 10 lg/ml. UH, zone of inhibition of unknown at concentration 20 lg/ml. UL, zone of inhibition of unknown at concentration 10 lg/ml.

=N-NH singlet at d 6.85-6.95 and singlet due to -N-NH signal appeared at d 2.11-2.20.

The 13C NMR spectra of synthesized compounds showed signals at d ~162 for ^C=O of quinazoline. Signals appeared at d 30.2-50.2 and d 35.70-55.30 for pyrazole Ca and Cb, respectively, signals appeared at d 160.0-165.2 for immine pyrazole C. Signals appeared at d 55.2-60.6 for -OCH3, for aromatic carbon at d 109.16-143.37, at d 165-175 for immine aromatic-C and at d 40.3-45.8 for N-CH3. The 13C NMR spectral data of 6a-m are summarized in experimental section (Lopez et al., 2000; Ahluwalia and Chandra, 2000).

3.1. Antibacterial activity

The synthesized compounds were tested their antibacterial activity in vitro by measuring zone of inhibition in mm by cup-plate method (Microbial Assay of Antibiotic, 2004; Hong et al., 1997). The antibacterial screening of compounds against different strains like two Gram positive bacteria viz. Staphyl-coccus aureus, Bacillus subtilis and two Gram negative bacteria viz. Escherichia coli, Certium at two different concentration 100 ig/mL and 50 ig/mL. DMSO was used as a blank and penicillin was used as an antibacterial standard. Nutrient agar was used as culture medium.

Compound 6a (R=H) was active against S. aureus and B. subtilis having 55.29% and 58.89% potency compared to penicillin. Compound 6f (R=3-Cl) and 6g (R=4-Cl) were inactive against both Gram positive bacteria. The remaining compounds possessed moderate to poor activity against both Gram positive stains.

Compound 6i (R=3-NO2) was active against E. coli and Certium having 63.51% and 64.31% potency compared to penicillin. 6a (R= H), 6f (R=3-Cl), 6g (R=4-Cl) and 6k [R=4-N(CH3)2] were inactive against both Gram negative bacteria. The remaining compounds possessed moderate to poor activity against both Gram negative stains.

The antibacterial activities of test compounds are summarized in Tables 3 and 4.

3.2. Antifungal activity

The antifungal activity of synthesized compounds in vitro by cup-plate method (Pai and Platt, 1995; Keliswar et al., 2005) by measuring zone of inhibition in mm against different stains of fungi viz. Aspergillus niger, Candida albicans. All the compounds with standard fluconazole were screened at two different concentrations 20 ig/mL and 10 ig/mL. Sabouraud dextrose agar was used as culture medium and 0.05% DMF used as solvent control. The compound 6e and 6f found moderated fungicidal activity, against A. niger and C. albicans compared to standard.

Compound 6e (R=2-Cl) showed moderate activity against A. niger and C. albicans and have 54.08% and 61.86% potency compared to fluconazole. 61 (R=2-OCH3) and 6m (R=4-OCH3) inactive against A. niger and C. albicans and remaining compounds of this series showed poor activity against A. niger and C. albicans compared to fluconazole.

The screening results of antifungal activity test compounds are summarized in Table 5.

Acknowledgements

The authors are thankful to the Principal, Arts, Science and Commerce College, Pilvai for providing laboratory facilities and Anandita Mehta, Department of Microbiology, ATIRA, Ahmedabad, for biological activities. The authors are also thankful to the Director, SICART-CVM, S P Uni V V Nagar for providing IR, 1H NMR, 13C NMR spectral data.

References

Ahluwalia, V.K., Chandra, R., 2000. J. Chem. Res. 4, 570. Archna, Srivastava, V.K., Chandra, Ramesh, Kumar, A., 2002. Ind. J.

Chem. 41B, 2373. Bahekar, R.H., Rao, A.R.R., 2000. Indian J. Pharm. Sci. 62, 41. Bekhit, A.A., Fahmy, H.T., 2003. Arch. Pharm. 336, 111. Gursoy, A., Buyuktimkin, S., Demirayak, S., Ekinci, A.C., 1990. Arch. Pharm. 323, 623.

Hong, C.Y., Kim, Y.K., Chang, JH., Kim, S.H., Choi, H., Nam,

D.H., Kim, Y.Z., Kwak, JH., 1997. J. Med. Chem. 40, 3584. Keliswar, S.B., Srivastava, K., Puri, S.K., Chauhan, P.M., 2005. Bio.

Org. Med. Chem. Lett. 15, 4957. Kuettell, S., Zambon, A., Kaisar, M., Brun, R., Scapozza, L., Parozzo,

R., 2007. J. Med. Chem. 50, 5833. Lopez, S.E., Rosales, M.E., Canelon, C.E., Valuerode, E.A., Narvaez, R.C., Charris, J.E., Enriz, R.D., 2000. Heterocycle Commun. 7, 473. Microbial Assay of Antibiotic, 2004. Eur. Pharmacopeias 4, 160. Nesrin, Kelekcl, G., Yabanoglu, S., Kupeli, E., Salgin, U., 2007.

Bioorg. Med. Chem. 15, 5775. Norris, T., Colon-Cruz, R., Ripin, D.H.P., 2005. Org. Biomol. Chem. 3, 1844.

Pai, S.T., Platt, M.W., 1995. Lett. Appl. Microbiol. 20, 14.

Pathak, V., Gupta, R., Gupta, N., 2008. Ind. J. Chem. 14B, 1303.

Propsavin, M., Torovic, L., Spaic, S., Stankov, S., Kapor, A., Tomic, Z., Popsavin, V., 2000. Tetrahedron 58, 569.

Refaie, F.M., Esmat, A.Y., Abdel Gawad, S.M., Ibrahim, A.M., Mohmed, M.A., 2005. Lipids Health Dis. 4, 22.

Soni, N., Pande, K., Kalsi, R., Gupta, T.K., Parmar, S.S., Barthwal, J.P., 1987. Res. Commun. Chem. Pathol. Pharmacol. 56, 1.

Tripathi, S., Pandey, B.R., Batrhwal, J.P., Kishor, K., Bhargava, K.P., 1980. Indian J. Physiol. Pharmacol. 24, 155.

Zhang, X., Li, X., Allan, G.F., Sbriscia, T., 2007. J. Med. Chem. 50, 3857.