Design, synthesis, and in vitro antimicrobial activities of novel azetidinyl-3-quinazolin-4-one hybrids

Article abstract of DOI:10.1007/s00044-011-9808-9

A series of 2-[(4'-oxo-3'-chloro-2'-phenylazetidin- 1'-ylamino)-methyl]-3- [N-isonicotinamide-yl]-quinazolin- 4-one hybrids were synthesized starting from anthranilic acid in basic media using chloroacetyl chloride and benzene as solvent. The structure of

Full text of DOI:10.1007/s00044-011-9808-9

MEDICINAL
CHEMISTRY
RESEARCH
Med Chem Res (2012) 21:2762–2771
DOI 10.1007/s00044-011-9808-9
ORIGINAL RESEARCH
Design, synthesis, and in vitro antimicrobial activities of novel
azetidinyl-3-quinazolin-4-one hybrids
•
Kruti Navin Myangar Jignesh Priyakant Raval
Received: 5 August 2011 / Accepted: 6 October 2011 / Published online: 20 October 2011
Ó Springer Science+Business Media, LLC 2011
Abstract A series of 2-[(40-oxo-30-chloro-20-phenylazeti-
din-10-ylamino)-methyl]-3-[N-isonicotinamide-yl]-quinaz-
olin-4-one hybrids were synthesized starting from
anthranilic acid in basic media using chloroacetyl chloride
and benzene as solvent. The structure of the synthesized
compounds has been evaluated on the basis of their ele-
mental (C, H, and N) and spectral analysis (IR, 1H NMR, and
13C NMR spectrometry). In vitro antimicrobial evaluation of
the synthesized compounds revealed that they posses
promising antimicrobial activity against some gram-positive
and gram-negative bacteria. Furthermore, compounds 7d
and 7f exhibited potent antitubercular activity.
broad variety of biological activity profile such as anti-
fungal (Patel et al., 2010), anti-inflammatory (Kumar and
Rajput, 2009), CNS depressant (Kashaw et al., 2009), anti-
microbial (Raval et al., 2011; Barat and Patel, 2010),
antitubercular (Pattan et al., 2006), antiviral (Selvam et al.,
2004), antiulcer (Patil et al., 2010), and insecticidal (Singh
et al., 2006) activities. The ring has ultimately proved to be
the main component of the pharmacophore. The extent of
the pharmacological effect of quinazolinone derivative
depends on the active group with which it is attached.
Recently, several scientists have elucidated that in qui-
nazolinone system sites like positions 2 and 3, can be
suitably modified by the introduction of various heterocy-
clic moieties to show excellent pharmacological results
(Hemalatha and Girija, 2011; Selvam et al., 2010).
Keywords Quinazoline-4-one ꢀ Isonicotinic acid
hydrazide ꢀ Azetidinone ꢀ Schiff base ꢀ Antibacterial ꢀ
Antifungal and antitubercular activity
Further natural and synthetic azetidinone derivatives,
commonly known as b-lactams, occupy a central place
among medicinally important compounds due to their
diverse and interesting antibiotic activities (Singh, 2003).
The activity of famous antibiotics such as penicillins,
cephalosporins, thienamycin, nocardicins, aztreonam, and
carbapenems are attributed to the presence of a 2-azetidi-
none ring in them. It has been accepted that the activities of
the compounds with b-lactam ring could be related to the
facility of being attacked by nucleophiles which presum-
ably exist in bacterial proteins. Some other significant
biological activities of 2-azetidinone are antibacterial
(Raval et al., 2009; Desai and Desai, 2006), anti-tubercular
(Joshi et al., 2003), anti-inflammatory (Bhati and Kumar,
2008), anticonvulsant (Jayachandran et al., 2009), antihy-
perlipidemic (Xu et al., 2007), anti-fungal (Raval et al.,
2009; Dandia et al., 2007), anitcytotoxic (Maia et al.,
2009) effects. This gave us an impetus to combine the two
biologically active nuclei in one molecular union for the
better therapeutic results.
Introduction
Fused nitrogen-containing heterocycles are important for
various vital processes are found as the structural frag-
ments of many natural compounds. The quinazolinone
structural motifs have attracted a great deal of interest due
to their ready accessibility, diverse chemical reactivity, and
K. N. Myangar ꢀ J. P. Raval (&)
Department of Pharmaceutical Chemistry, Ashok & Rita Patel
Institute of Integrated Study and Research in Biotechnology and
Allied Sciences (ARIBAS), New Vallabh Vidyanagar 388121,
Gujarat, India
e-mail: drjpraval@yahoo.co.in
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Med Chem Res (2012) 21:2762–2771
Materials and methods
Experimental
2763
solvent was distilled out. On cooling, a crystalline solid
obtained, which was recrystalized from methanol. Yield,
69%; m.p., 207°C. IR (mmax in cm-1): 3319 (NH), 3062 (C–
H aromatic), 2945 (C–H aliphatic), 1685 (C=O of amide,
C=O str), 1663 (C=O of quinazolinone), 1340 (C=N), 1267
All the melting points were determined on a PMP-DM sci-
entific melting point apparatus and are uncorrected. The
purity of compounds was checked by TLC (0.5 mm thick-
ness) using silica gel-G coated Al-plates (Merck) and spots
were visualized by exposing the dry plates to iodine vapors.
IR spectra (mmax in cm-1) were recorded on a Perkin Elmer
spectrum BX series FT-IR spectrometer using KBr tech-
1
(N–N). H NMR (400 MHz, DMSO-d6) d ppm: 1.94 (s,
1H, NH exchangeable), 2.14 (bs, 2H, NH2 exchangeable),
2.86 (s, 2H, CH2), 7.53–9.16 (m, 8H, Ar–H), 8.24 (s, 1H,
NH–CO). 13C NMR (400 MHz, DMSO-d6) d ppm: 52.75
(C15), 122.85–133.30 (C2–C6, C10–C11), 142.17 (C14),
147.86 (C1), 149.94 (C12–C13), 164.16 (C8), 167.09 (C7),
167.48 (C9). Analysis for C15H14N6O2 (310.12). Calcd: C,
58.06; H, 4.55; N, 27.08%. Found: C, 58.24; H, 4.47; N,
27.19%. MS: m/z [310.12]?.
1
nique. H NMR and 13C NMR spectra were recorded on a
Bruker WM 400 FT MHz NMR instrument, using DMSO-d6
as solvent and TMS as internal reference (chemical shifts in d
ppm). The elemental analysis (C, H, and N) of compounds
was performed on Carlo Erba—1108 elemental analyzer.
General procedure for the synthesis of 2-
benzylidenehydrazinomethyl-3-[N-isonicotinamide-yl]-
quinazoline-4-one 6a–k
N-Chloroacetyl anthranilic acid 2
N-Chloroacetyl anthranilic acid was synthesized using
anthranilic acid 1 (0.01 mol) and chloroacetyl chloride
(0.02 mol) according to reported procedure (Kumar et al.,
2007). The solid thus obtained was recrystallized from
ethanol to give the title compound. Yield, 72%; m.p.,
169°C.
An equimolar amount of 2-Hydrazinomethyl-3-[N-isonic-
otinamide-yl]-quinazoline-4-one 4 (0.01 mol) and appro-
priate aromatic aldehyde 5a–k (0.01 mol) was dissolved in
absolute ethanol (50 ml) in the presence of catalytic
amount of glacial acetic acid. The reaction mixture was
refluxed for 7–8 h and the reaction was monitored by TLC.
After completion of reaction, the reaction mass was cooled
and was poured onto crushed ice to get the desire com-
pounds, 6a–k which were recrystallized using ethanol.
2-Chloromethyl-3-(N-isonicotinamide-yl)-4H-
quinazolinone 3
N-Chloroacetyl anthranilic acid 2 (0.01 mol) was refluxed for
3 h with isoniazid in 100 ml of benzene under anhydrous
condition and the progress of the reaction was monitored by
TLC. After completion of the reaction, reaction mixture was
distilled out and the residue was washed with hot water. The
solid thus obtained was recrystallized from acetone. Yield,
76%; m.p., 213°C. IR (mmax in cm-1): 3327 (NH), 3051 (C–H
aromatic), 2948 (C–H aliphatic), 1693 (C=O of amide, C=O
str), 1655 (C=O of quinazolinone), 1332 (C=N), 729 (C–Cl).
1H NMR (400 MHz, DMSO-d6) d ppm: 3.46 (s, 2H, CH2),
7.53–8.94 (m, 8H, Ar–H), 8.17 (s, 1H, NH–CO). 13C NMR
(400 MHz, DMSO-d6) d ppm: 44.31 (C15), 122.43–133.18
(C2–C6, C10–C11), 142.27 (C14), 147.82 (C1), 150.26 (C12–
C13), 164.23 (C8), 166.96 (C7), 167.24 (C9). Analysis for
C15H11ClN4O2 (314.06). Calcd:C, 57.24;H, 3.52; N, 17.80%.
Found: C, 57.32; H, 3.63; N, 17.94%. MS: m/z [314.06]?.
2-Benzylidenehydrazinomethyl-3-N-isonicotinamide-yl]-
quinazoline-4-one 6a Yield, 69%; m.p., 204°C. IR (mmax
in cm-1): 3320 (NH), 3034 (C–H aromatic), 2952 (C–H
aliphatic),1698 (C=O of amide, C=O str), 1650 (C=O of
quinazolinone), 1623 (N=CH), 1324 (C=N), 1267 (N–N).
1H NMR (400 MHz, DMSO-d6) d ppm : 2.32 (s, 1H, NH
exchangeable), 2.89 (s, 2H, CH2), 7.21–8.09 (m, 13H, Ar–
H), 8.21 (s, 1H, NH–CO), 8.31 (s, 1H, N=CH–Ar). 13C
NMR (400 MHz, DMSO-d6)
d ppm: 49.67 (C15),
122.63–133.18 (C2–C6, C10–C11, C17–C21), 142.16 (C14),
147.80 (C1), 150.48 (C12–C13), 154.64 (C16), 154.78 (C22),
163.86 (C8), 167.16 (C7), 167.28 (C9). Analysis for
C22H18N6O2 (398.42). Calcd: C, 66.32; H, 4.55; N%,
21.09. Found: C, 66.19; H, 4.63; N, 21.26%. MS:
m/z [398.15]?.
2-[(o-Nitrobenzylidene)-hydrazinomethyl]-3-[N-isonico-
tinamide-yl]-quinazoline-4-one 6b Yield, 65%; m.p.,
240°C. IR (mmax in cm-1): 3316 (NH), 3041 (C–H aro-
matic), 2951 (C–H aliphatic), 1687 (C=O of amide, C=O
str), 1652 (C=O of quinazolinone), 1618 (N=CH), 1317
2-Hydrazinomethyl-3-[N-isonicotinamide-yl]-quinazoline-
4-one 4
Compound 3 (0.01 mol) was dissolved in ethanol with
stirring and hydrazine hydrate (99%, 0.02 mol) was added.
The reaction mixture was refluxed till completion of the
reaction (7–8 h), which was checked by TLC. The excess
1
(C=N), 1258 (N–N). H NMR (400 MHz, DMSO-d6) d
ppm : 2.19 (s, 1H, NH exchangeable), 2.64 (s, 2H,
CH2), 6.93–7.89 (m, 12H, Ar–H), 8.15 (s, 1H, NH–CO),
123

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Med Chem Res (2012) 21:2762–2771
8.23 (s, 1H, N=CH–Ar). 13C NMR (400 MHz, DMSO-d6)
d ppm: 49.39 (C15), 122.86–133.24 (C2–C6, C10–C11,
C17,C19–C22), 142.09 (C14), 147.86 (C1), 148.93 (C18),
149.78 (C12–C13), 154.64 (C16), 154.81 (C16), 164.17 (C8),
167.32 (C7), 167.43 (C9). Analysis for C22H17N7O4
(443.41). Calcd: C, 59.59; H, 3.86; N, 22.11%. Found: C,
59.42; H, 3.97; N, 21.96%. MS: m/z [443.13]?.
3.96; N, 16.41%. Found: C, 61.13; H, 3.74; N, 16.32%.
MS: m/z [432.11]?.
2-[(p-Chlorobenzylidene)-hydrazinomethyl]-3-[N-isonic-
otinamide-yl]-quinazoline-4-one 6f Yield, 73%; m.p.,
228°C. IR (mmax in cm-1): 3323 (NH), 3064 (C–H aro-
matic), 2953 (C–H aliphatic),1697 (C=O of amide, C=O
str), 1657 (C=O of quinazolinone), 1628 (N=CH), 1311
1
2-[(m-Nitrobenzylidene)-hydrazinomethyl]-3-[N-isonicoti-
namide-yl]-quinazoline-4-one 6c Yield, 66%; m.p.,
207°C. IR (mmax in cm-1): 3320 (NH), 3041 (C–H aro-
matic), 2946 (C–H aliphatic), 1681 (C=O of amide, C=O
str), 1643 (C=O of quinazolinone), 1623 (N=CH) 1326
(C=N), 1271 (N–N). H NMR (400 MHz, DMSO-d6) d
ppm : 2.28 (s, 1H, NH exchangeable), 2.75 (s, 2H, CH2),
6.42-7.22 (m, 12H, Ar–H), 7.96 (s, 1H, N=CH–Ar), 8.29 (s,
1H, NH–CO). 13C NMR (400 MHz, DMSO-d6) d ppm:
49.46 (C15), 122.45–133.28 (C2–C6, C10–C11, C17–C20),
136.17 (C21), 142.15 (C14), 147.79 (C1), 150.98 (C12–C13),
154.57 (C16), 164.36 (C8), 167.10 (C9), 167.15 (C7).
Analysis for C22H17N6O2Cl (432.86). Calcd: C, 61.04; H,
3.96; N, 19.41%. Found: C, 61.27; H, 3.82; N, 19.51%.
MS: m/z [432.11]?.
1
(C=N), 1268 (N–N). H NMR (400 MHz, DMSO-d6) d
ppm : 2.13 (s, 1H, NH exchangeable), 2.65 (s, 2H, CH2),
6.79–7.98 (m, 12H, Ar–H), 8.17 (s, 1H, N=CH–Ar), 8.23
(s, 1H, NH–CO). 13C NMR (400 MHz, DMSO-d6) d ppm:
49.64 (C15), 122.83–133.30 (C2–C6, C10–C11, C17–
C19,C21–C22), 142.16 (C14), 147.83 (C1), 148.64 (C20),
150.12 (C12–C13), 154.58 (C16), 164.09 (C8), 167.21 (C9),
167.28 (C7). Analysis for C22H18N7O4 (443.41). Calcd: C,
59.59; H, 3.86; N, 22.11%. Found: C, 59.52; H, 3.95; N,
22.34%. MS: m/z [443.13]?.
2-[(o-Hydroxybenzylidene)-hydrazinomethyl]-3-[N-isonic-
otinamide-yl]-quinazoline-4-one 6g Yield, 68%; m.p.,
214°C. IR (mmax in cm-1): 3319 (NH), 3059 (C–H aro-
matic), 2947 (C–H aliphatic), 1685 (C=O of amide, C=O
str), 1655 (C=O of quinazolinone), 1621 (N=CH), 1318
1
(C=N), 1271 (N–N). H NMR (400 MHz, DMSO-d6) d
2-[(p-Nitrobenzylidene)-hydrazinomethyl]-3-[N-isonico-
tinamide-yl]-quinazoline-4-one 6d Yield, 70%; m.p.,
215°C. IR (mmax in cm-1): 3326 (NH), 3037 (C–H aro-
matic), 2948 (C–H aliphatic), 1694 (C=O of amide, C=O
str), 1654 (C=O of quinazolinone), 1617 (N=CH), 1312
ppm : 2.29 (s, 1H, NH exchangeable), 2.53 (s, 2H, CH2),
6.70-7.93 (m, 12H, Ar–H), 8.16 (s, 1H, NH–CO), 8.35 (ss,
1H, N=CH–Ar). 13C NMR (400 MHz, DMSO-d6) d ppm:
49.66 (C15), 122.87–133.20 (C2–C6, C10–C11, C17,C19–
C22), 142.19 (C14), 147.72 (C1), 150.14 (C12–C13), 154.61
(C16), 157.92 (C18), 164.29 (C8), 167.19 (C7), 167.20 (C9).
Analysis for C22H18N6O3 (414.42). Calcd: C, 63.76; H,
4.38; N, 20.28%. Found: C, 63.61; H, 4.29; N, 20.36%.
MS: m/z [414.14]?.
1
(C=N), 1265 (N–N). H NMR (400 MHz, DMSO-d6) d
ppm : 2.31 (s, 1H, NH exchangeable), 2.58 (s, 2H, CH2),
6.96–7.53 (m, 12H, Ar–H), 7.92 (s, 1H, NH–CO), 8.25 (s,
1H, N=CH–Ar). 13C NMR (400 MHz, DMSO-d6) d ppm:
49.71 (C15), 122.98–133.22 (C2–C6, C10–C11, C17–C20),
137.37 (C22), 142.13 (C14), 147.85 (C1), 150.23 (C12–C13),
150.81 (C21), 154.67 (C16), 163.98 (C8), 167.14 (C7),
167.20 (C9). Analysis for C22H17N7O4 (443.41). Calcd: C,
59.59; H, 3.86; N, 22.11%. Found: C, 59.68; H, 3.74; N,
21.36%. MS: m/z [443.13]?.
2-[(p-Hydroxybenzylidene)-hydrazinomethyl]-3-[N-isonic-
otinamide-yl]-quinazoline-4-one 6h Yield, 62%; m.p.,
225°C. IR (mmax in cm-1): 3328 (NH), 3039 (C–H aro-
matic), 2949 (C–H aliphatic),1693 (C=O of amide, C=O
str), 1648 (C=O of quinazolinone), 1612 (N=CH), 1298
1
(C=N), 1257 (N–N). H NMR (400 MHz, DMSO-d6) d
2-[(o-Chlorobenzylidene)-hydrazinomethyl]-3-[N-isonico-
tinamide-yl]-quinazoline-4-one 6e Yield, 67%; m.p.,
224°C. IR (mmax in cm-1): 3328 (NH), 3070 (C–H aro-
matic), 2955 (C–H aliphatic), 1693 (C=O of amide, C=O
str), 1649 (C=O of quinazolinone), 1620 (N=CH), 1311
ppm : 2.21 (s, 1H, NH exchangeable), 2.80 (s, 2H, CH2),
6.56–8.04 (m, 12H, Ar–H), 8.23 (s, 1H, N=CH–Ar), 8.34
(s, 1H, NH–CO). 13C NMR (400 MHz, DMSO-d6) d ppm:
49.38 (C15), 122.86–133.24 (C2–C6, C10–C11,C17–C20,C22),
142.23 (C14), 147.68 (C1), 150.05 (C12–C13), 154.90 (C16),
159.53 (C21), 164.15 (C8), 167.34 (C7), 167.56 (C9).
Analysis for C22H18N6O3 (414.42). Calcd: C, 63.76; H,
4.38; N, 20.28%. Found: C, 63.89; H, 4.46; N, 20,17%.
MS: m/z [414.14]?.
1
(C=N), 1263 (N–N). H NMR (400 MHz, DMSO-d6) d
ppm : 2.16 (s, 1H, NH exchangeable), 2.48 (s, 2H, CH2),
6.53-7.80 (m, 12H, Ar–H), 8.02 (s, 1H, N=CH–Ar), 8.34 (s,
1H, NH–CO). 13C NMR (400 MHz, DMSO-d6) d ppm:
49.71 (C15), 122.89–133.24 (C2–C6, C10–C11, C17,C19–
C22), 134.37 (C18), 142.17 (C14), 147.74 (C1), 149.98 (C12–
C13), 154.93 (C16), 164.30 (C8), 167.21 (C7), 167.57 (C9).
Analysis for C22H17N6O2Cl (432.86). Calcd: C, 61.04; H,
2-[(p-Methoxybenzylidene)-hydrazinomethyl]-3-[N-iso-
nicotinamide-yl]-quinazoline-4-one 6i Yield, 71%;
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Med Chem Res (2012) 21:2762–2771
2765
m.p., 212°C. IR (mmax in cm-1): 3321 (NH), 3060 (C–H
aromatic), 2950 (C–H aliphatic),1689 (C=O of amide, C=O
str), 1645 (C=O of quinazolinone), 1626 (N=CH), 1340
To a mixture of appropriate compound 6a–k (0.01 mol),
triethylamine (1.0 ml) in dry benzene (50 ml), chloroacetyl
chloride (0.015 mol) was added at 50°C temperature. Then
resultant reaction mass was allowed to come to room
temperature, and was stirred for 40 min. After being stir-
red, the reaction mass was refluxed (7–8 h), Reaction
progress was monitored using TLC. After completion of
reaction, resultant mass was filtered to remove triethyl-
amine hydrogen chloride and the solution was poured onto
crushed ice with constant stirring. The solid thus obtained
was recrystallized from methanol to yield desired com-
pounds 7a–k.
1
(C=N), 1256 (N–N). H NMR (400 MHz, DMSO-d6) d
ppm : 2.13 (s, 1H, NH exchangeable), 2.58 (s, 2H, CH2),
6.37–7.90 (m, 12H, Ar–H), 8.21 (s, 1H, NH–CO), 8.36 (s,
1H, N=CH–Ar). 13C NMR (400 MHz, DMSO-d6) d ppm:
49.37 (C15), 56.14 (C23), 122.87–133.14 (C2–C6, C10–
C11,C17–C20,C22), 142.23 (C14), 147.68 (C1), 150.14 (C12–
C13), 154.51 (C16), 163.94 (C8), 164.46 (C21), 167.18 (C9),
167.21 (C7). Analysis for C23H20N6O3 (428.44). Calcd: C,
64.48; H, 4.71; N, 19.62%. Found: C, 64.59; H, 4.90; N,
19.48%. MS: m/z [428.16]?.
2-[(40-Oxo-30-chloro-20-phenylazetidin-10-ylamino)-methyl]-
3-[N-isonicotinamide-yl]-quinazolin-4-one 7a Yield, 62%;
m.p., 231°C. IR (mmax in cm-1): 3342 (NH), 3053 (C–H
aromatic), 1790 (C=O of b-lactam), 2943 (C–H aliphatic),
1650 (C=O of quinazolinone), C=O str 1305 (C=N), 1617
(C=O of amide, C=O str),1250 (N–N), 753 (C–Cl). 1H NMR
(400 MHz, DMSO-d6) d ppm: 2.51 (s, 2H, CH2), 4.75 (d,
J = 9.0, 1H, CH–Cl), 5.31 (d, J = 9.1, 1H, N–CH–Ar), 5.64
(s, 1H, NH), 6.47–7.72 (m, 13H, Ar–H), 8.47 (s, 1H, NH–
CO). 13C NMR (400 MHz, DMSO-d6) d ppm: 47.24 (C15),
62.17 (C17), 64.39 (C18), 122.79–133.21 (C2–C6, C10–C11,
C19–C23), 142.15 (C14), 142.37 (C24), 147.82 (C1), 150.13
(C12–C13), 163.19 (C16), 164.18 (C8), 167.24 (C7), 167.58
(C9). Analysis for C24H19ClN6O3 (474.90). Calcd: C, 60.70;
H, 4.03; N, 17.70%. Found: C, 60.89; H, 4.07; N, 17.49%.
MS: m/z [474.12]?.
2-[(p-Ethylbenzylidene)-hydrazinomethyl]-3-[N-isonicotina-
mide-yl]-quinazoline-4-one 6j Yield, 65%; m.p., 231°C. IR
(mmax in cm-1): 3328 (NH), 3047 (C–H aromatic), 2946 (C–
H aliphatic), 1690 (C=O of amide, C=O str), 1654 (C=O of
quinazolinone), 1615 (N=CH), 1309 (C=N), 1258 (N–N). 1H
NMR (400 MHz, DMSO-d6) d ppm : 1.36 (t, 3H, CH3), 2.16
(s, 1H, NH exchangeable), 2.46 (q, 2H, CH2), 2.60 (s, 2H,
CH2-NH), 6.48–8.03 (m, 12H, Ar–H), 8.19 (s, 1H, N=CH–
Ar), 8.21 (s, 1H, NH–CO). 13C NMR (400 MHz, DMSO-d6)
d ppm: 16.23(CH2CH3), 28.71 (CH2CH3), 49.61 (C15),
122.79–133.26 (C2–C6, C10–C11,C17–C20,C22), 142.26
(C14,C21), 147.76 (C1), 150.16 (C12–C13), 154.87 (C16),
164.20 (C8), 167.12 (C7), 167.51 (C9). Analysis for
C24H22N6O2 (426.47). Calcd: C, 67.69; H, 5.20; N, 19.71%.
Found: C, 67.89; H, 4.97; N, 19.49%. MS: m/z [426.18]?.
2-[(p-Bromobenzylidene)-hydrazinomethyl]-3-[N-isonic-
otinamide-yl]-quinazoline-4-one 6k Yield, 70%; m.p.,
210°C. IR (mmax in cm-1): 3323 (NH), 3065 (C–H aromatic),
2945 (C–H aliphatic), 1696 (C=O of amide, C=O str), 1646
(C=O of quinazolinone), 1629 (N=CH), 1314 (C=N), 1264
(N–N). 1H NMR (400 MHz, DMSO-d6) d ppm : 1.94 (s, 1H,
NH exchangeable), 2.91 (s, 2H, CH2), 6.69–7.70 (m, 12H,
2-[(40-Oxo-30-chloro-20-{o-nitrophenyl}-azetidin-10-ylami-
no)-methyl]-3-[N-isonicotinamide-yl]-quinazoline-4-one
7b Yield, 54%; m.p., 263°C. IR (mmax in cm-1): 3338 (NH),
2953 (C–H aromatic), 1731 (C=O of b-lactam), 2948 (C–H
aliphatic), 1645 (C=O of quinazolinone),1506 (NO2), 1637
(C=O of amide, C=O str), 1346 (C=N), 1270 (N–N), 747 (C–
1
Cl). H NMR (400 MHz, DMSO-d6) d ppm : 2.73 (s, 2H,
Ar–H), 7.88 (s, 1H, N=CH–Ar), 8.25 (s, 1H, NH–CO). 13
C
CH2), 4.79 (d, J = 9.0, 1H, CH–Cl), 5.21 (d, J = 9.1, 1H,
N–CH–Ar), 5.68 (s, 1H, NH), 6.63–7.89 (m, 12H, Ar–H),
8.19 (s, 1H, NH–CO exchangeable). 13C NMR (400 MHz,
DMSO-d6) d ppm: 48.88 (C15), 54.32 (C17), 64.73 (C18),
121.55–133.19 (C2–C6, C10–C11, C19, C21–C23), 137.46
(C24), 142.18 (C14), 147.13 (C20), 147.85 (C1), 150.34 (C12–
C13), 161.86 (C8), 166.78 (C16), 167.16 (C7), 167.24 (C9).
Analysis for C24H18ClN7O5 (519.90). Calcd: C, 55.45; H,
3.49; N, 18.86%. Found: C, 55.13; H, 3.78; N, 18.63%. MS:
m/z [519.11]?.
NMR (400 MHz, DMSO-d6) d ppm: 49.77(C15),
122.85–133.16 (C2–C6, C10–C11,C17–C22), 142.19
(C14,C21), 147.82 (C1), 150.34 (C12-C13), 154.53 (C16),
164.31 (C8), 166.89 (C7), 167.18 (C9). Analysis for
C22H17N6O2Br (477.31). Calcd: C, 55.36; H, 3.59;
N, 17.61%. Found: C, 55.12; H, 3.84; N, 17.39%. MS:
m/z [476.06]?.
General procedure for the synthesis of 2-[(40-oxo-30-
chloro-20-phenylazetidin-10-ylamino)-methyl]-3-[N-
isonicotinamide-yl]-quinazolin-4-one 7a–k
2-[(40-Oxo-30-chloro-20-{m-nitrophenyl}-azetidin-10-ylami-
no)-methyl]-3-[N-sonicotinamide-yl]-quinazoline-4-one
7c Yield, 64%; m.p., 261°C. IR (mmax in cm-1): 3340
(NH), 2934 (C–H aromatic), 1720 (C=O of b-lactam), 2954
(C–H aliphatic), 1652 (C=O of quinazolinone), 1631 (C=O
Title compounds 7a–k were synthesized according to
reported procedure (Kumar et al., 2007) by doing minor
modification as below.
123

2766
Med Chem Res (2012) 21:2762–2771
of amide, C=O str), 1518 (NO2), 1346 (C=N), 1251 (N–N),
1
(C–H aliphatic), 1681 (C=O of amide, C=O str), 1646
(C=O of quinazolinone), 1313 (C=N), 1281 (N–N), 758
743 (C–Cl). H NMR (400 MHz, DMSO-d6) d ppm : 2.63
1
(s, 2H, CH2), 4.93 (d, J = 9.0, 1H, CH–Cl), 5.46 (d,
J = 9.1, 1H, N–CH–Ar), 5.73 (s, 1H, NH), 7.19–8.07 (m,
12H, Ar–H), 8.38 (s, 1H, NH–CO exchangeable). 13C
NMR (400 MHz, DMSO-d6) d ppm: 47.54 (C15), 61.74
(C17), 64.59 (C18), 122.18–133.20 (C2–C6, C10–C11, C19,
C20, C21,C23), 142.13 (C14),143.26 (C24), 147.78 (C1),
148.16 (C22), 150.43 (C12-C13), 163.45 (C16), 164.97 (C8),
167.18 (C7), 167.41 (C9). Analysis for C24H18ClN7O5
(519.90). Calcd: C, 55.45; H, 3.49; N, 18.86%. Found: C,
55.63; H, 3.37; N, 18.80%. MS: m/z [519.11]?.
(C–Cl). H NMR (400 MHz, DMSO-d6) d ppm : 2.84 (s,
2H, CH2), 4.66 (d, J = 9.0, 1H, CH–Cl), 5.69 (d, J = 9.1,
1H, NH), 5.87 (s, 1H, N–CH–Ar), 6.74-7.92 (m, 12H, Ar–
H), 8.31 (s, 1H, NH–CO exchangeable). 13C NMR
(400 MHz, DMSO-d6) d ppm: 47.49 (C15), 62.83 (C17),
64.89 (C18), 122.67–133.30 (C2–C6, C10–C11, C19–C23),
140.43 (C24), 142.18 (C14), 147.76 (C1), 150.32 (C12–C13),
163.43 (C16), 164.37 (C8), 167.18 (C7), 167.21 (C9).
Analysis for C24H18Cl2N6O3 (509.34). Calcd: C, 56.59; H,
3.56; N, 16.50%. Found: C, 56.32; H, 3.77; N, 16.82%.
MS: m/z [509.08]?.
2-[(40-Oxo-30-chloro-20-{p-nitrophenyl}-azetidin-10-ylami-
no)-methyl]-3-[N-sonicotinamide-yl]-quinazoline-4-one
7d Yield, 53%; m.p., 259°C. IR (mmax in cm-1): 3342
(NH), 3087 (C–H aromatic), 2954 (C–H aliphatic), 1768
(C=O of b-lactam), 1648 (C=O of quinazolinone), 1632
(C=O of amide, C=O str), 1526 (NO2), 1325 (C=N), 1260
(N–N), 751 (C–Cl). 1H NMR (400 MHz, DMSO-d6) d ppm :
2.63 (s, 2H, CH2), 4.53 (d, J = 9.0, 1H, CH–Cl), 5.47
(d, J = 9.1, 1H, NH), 5.79 (s, 1H, N–CH–Ar), 6.82-7.94
(m, 12H, Ar–H), 8.17 (s, 1H, NH–CO exchangeable). 13C
NMR (400 MHz, DMSO-d6) d ppm: 47.95 (C15), 62.52
(C17), 64.89 (C18), 122.48–133.40 (C2–C6, C10–C11, C19–
C22), 142.08 (C14),146.36 (C23), 147.83 (C1), 148.58 (C24),
150.22 (C12–C13), 163.76 (C16), 164.32 (C8), 166.98 (C7),
167.13 (C9). Analysis for C24H18ClN7O5 (519.90). Calcd:
C, 55.45; H, 3.49; N, 18.86%. Found: C, 55.39; H, 3.65; N,
18.57%. MS: m/z [519.11]?.
2-[(40-Oxo-30-chloro-20-{o-hydroxyphenyl} azetidin-10-yla-
mino)-methyl]-3-[N-isonicotinamide-yl]-quinazoline-4-one
7g Yield, 57%; m.p., 293°C. IR (mmax in cm-1): 3342
(NH), 3224 (OH), 3100 (C–H aromatic), 2953 (C–H ali-
phatic),1728 (C=O of b-lactam), 1658 (C=O of quinazoli-
none), 1625 (C=O of amide, C=O str), 1315 (C=N), 1273
(N–N), 739 (C–Cl). 1H NMR (400 MHz, DMSO-d6) d ppm
: 2.26 (s, 2H, CH2), 4.79 (d, J = 9.0, 1H, CH–Cl), 4.81 (d,
J = 9.1, 1H, OH), 5.32 (s, 1H, N–CH–Ar), 5.63 (s, 1H,
NH), 6.91–7.97 (m, 12H, Ar–H), 8.13 (s, 1H, NH–CO
exchangeable). 13C NMR (400 MHz, DMSO-d6) d ppm:
47.69 (C15), 52.34 (C17), 64.56 (C18), 121.78–133.19 (C2–
C6, C10–C11, C19, C21–C24), 142.14 (C14), 147.86 (C1),
150.14 (C12–C13), 155.83 (C20), 163.67 (C16), 164.17 (C8),
166.93 (C7), 167.48 (C9). Analysis for C24H19ClN6O4
(490.90). Calcd: C, 58.72; H, 3.90; N, 17.12%. Found: C,
58.86; H, 3.79; N, 17.33%. MS: m/z [490.12]?.
2-[(40-Oxo-30-chloro-20-{o-chlorophenyl}-azetidin-10-yla-
mino)-methyl]-3-[N-sonicotinamide-yl]-quinazoline-4-one
7e Yield, 58%; m.p., 318°C. IR (mmax in cm-1): 3349
(NH), 3057 (C–H aromatic), 1713 (C=O of b-lactam), 2960
(C–H aliphatic), 1644 (C=O of quinazolinone), 1591 (C=O
of amide, C=O str), 1316 (C=N), 1220 (N–N), 753 (C–Cl).
1H NMR (400 MHz, DMSO-d6) d ppm : 2.32 (s, 2H, CH2),
4.70 (d, J = 9.0, 1H, CH–Cl), 5.02 (d, J = 9.1, 1H, N–
CH–Ar), 5.05 (s, 1H, NH), 7.30–8.17 (m, 12H, Ar–H), 8.98
(s, 1H, NH–CO exchangeable). 13C NMR (400 MHz,
DMSO-d6) d ppm: 42.33 (C15), 60.38 (C17), 60.38 (C18),
122.34–133.32 (C2–C6, C10–C11, C19–C23), 142.15 (C14),
142.76 (C24), 147.89 (C1), 150.25 (C12–C13), 158.69 (C8),
163.65 (C16), 167.13 (C9), 171.94 (C7). Analysis for
C24H18Cl2N6O3 (509.34). Calcd: C, 56.59; H, 3.56;
N, 16.50%. Found: C, 56.67; H, 3.49; N, 16.67%. MS:
m/z [509.08]?.
2-[(40-Oxo-30-chloro-20-{p-hydroxyphenyl} azetidin-10-yla-
mino)-methyl]-3-[N-isonicotinamide-yl]-quinazoline-4-one
7h Yield, 55%; m.p., 275°C. IR (mmax in cm-1): 3336
(NH), 3059 (–OH), 2946 (C–H aromatic), 2934 (C–H ali-
phatic),1725 (C=O of b-lactam), 1651 (C=O of quinazoli-
none), 1641 (C=O of amide, C=O str), 1339 (C=N), 1267
(N–N), 754 (C–Cl). 1H NMR (400 MHz, DMSO-d6) d ppm
: 2.48 (s, 2H, CH2), 4.87 (d, J = 9.0, 1H, CH–Cl), 4.97 (s,
1H, OH), 5.16 (d, J = 9.1, 1H, N–CH–Ar), 5.89 (s, 1H,
NH), 6.73–7.89 (m, 12H, Ar–H), 8.26 (s, 1H, NH–CO
exchangeable). 13C NMR (400 MHz, DMSO-d6) d ppm:
47.67 (C15), 62.53 (C17), 64.37 (C18), 122.31–133.34 (C2–
C6, C10–C11, C19–C22,C24), 142.17 (C14), 147.85 (C1),
150.52 (C12–C13), 155.27 (C23), 163.43 (C16), 163.87(C8),
167.25 (C7), 167.29 (C9). Analysis for C24H19ClN6O4
(490.90). Calcd: C, 58.72; H, 3.90; N, 17.12%. Found: C,
58.86; H, 3.79; N, 17.33%. MS: m/z [490.12]?.
2-[(40-Oxo-30-chloro-20-{p-chlorophenyl} azetidin-10-yla-
mino)-methyl]-3-[N-isonicotinamide-yl]-quinazoline-4-one
7f Yield, 59%; m.p., 283°C. IR (mmax in cm-1): 3346
(NH), 3049 (C–H aromatic), 1773 (C=O of b-lactam), 2957
2-[(40-Oxo-30-chloro-20-{p-methoxyphenyl} azetidin-10-yla-
mino)-methyl]-3-[N-isonicotinamide-yl]-quinazoline-4-one
7i Yield, 61%; m.p., 252°C. IR (mmax in cm-1): 3344
123

Med Chem Res (2012) 21:2762–2771
2767
Determination of antimicrobial activities
(NH), 3086 (C–H aromatic), 2948 (C–H aliphatic), 2869
(–OCH3), 1710 (C=O of b-lactam), 1647 (C=O of qui-
nazolinone), 1609 (C=O of amide, C=O str), 1399 (C=N),
In vitro evaluation of antibacterial and antifungal activities
1
1237 (N–N), 767 (C–Cl). H NMR (400 MHz, DMSO-d6)
The minimal inhibition concentration (MIC) of synthesized
compounds was carried out by broth dilution method
(Rattan, 2000). DMSO was used as the diluents to get
desired concentration of drugs to test upon standard bac-
terial strains such as some gram-positive bacteria S. aureus
(MTCC 96), S. pyogenus (MTCC 442), B. subtilis (MTCC
441) and gram-negative bacteria E. coli (MTCC 443),
P. aeruginosa (MTCC 1688), Kl. pneumoniae (MTCC109),
S. typhi (MTCC 98), and fungal strain such as C. albicans
(MTCC 227), A. niger (MTCC 282), A. clavatus (MTCC
1323). Serial dilutions were prepared for the purpose of the
primary and secondary screening. The control tube con-
taining no antibiotic was immediately sub cultured (before
inoculation) by spreading a loopful (106 cfu/ml) of bacteria
evenly over a quarter of Petri plate with Muller Hinton agar
medium suitable for the growth of the test organism and
placed for incubation at 37°C overnight. The lowest con-
centration of the drugs inhibiting growth of the test bac-
terium was recorded as the MIC. All the tubes not showing
visible growth (in the same manner as control tube
described above) was sub-cultured and incubated overnight
at 37°C. The amount of growth from the control tube
before incubation (which represents the original inoculum)
was compared. Subcultures might show: similar number of
colonies indicating bacteriostatic; a reduced number of
colonies indicating a partial or slow bactericidal activity
and no growth if the whole inoculum has been killed. Each
synthesized drug was diluted obtaining 2000 lg/ml con-
centration, as a stock solution. In the primary screening
500, 250, and 125 lg/ml of the synthesized drugs were
taken. The active synthesized drugs found in this primary
screening were further tested in a second set of dilution
against all microorganisms. The drugs found active in
primary screening were similarly diluted to obtain 100, 50,
25, 12.5, 6.250, 3.125, and 1.5625 lg/ml concentrations.
The highest dilution showing at least 99% inhibition is
taken as MIC.
d ppm : 2.27 (s, 2H, CH2), 3.47 (s, 3H, OCH3), 4.79 (d,
J = 9.0, 1H, CH–Cl), 5.34 (d, J = 9.1, 1H, N–CH–Ar),
5.73 (s, 1H, NH), 6.89–7.75 (m, 12H, Ar–H), 7.98 (s, 1H,
NH–CO exchangeable). 13C NMR (400 MHz, DMSO-d6) d
ppm: 47.68 (C15), 56.21 (C25), 62.78 (C17), 64.46 (C18),
122.29–133.26 (C2–C6, C10–C11, C19–C22), 134.67 (C24),
142.20 (C14), 147.89 (C1), 150.17 (C12–C13), 160.14 (C23),
163.30 (C16), 164.23 (C8), 167.18 (C7), 167.43 (C9).
Analysis for C25H21ClN6O4 (504.93). Calcd: C, 59.47; H,
4.19; N, 16.64%. Found: C, 59.56; H, 4.35; N, 16.43%.
MS: m/z [504.13]?.
2-[(40-Oxo-30-chloro-20-{p-ethylphenyl} azetidin-10-ylami-
no)-methyl]-3-[N-isonicotinamide-yl]-quinazoline-4-one
7j Yield, 69%; m.p., 297°C. IR (mmax in cm-1): 3349
(NH), 3085 (C–H aromatic), 2953 (C–H aliphatic), 1770
(C=O of b-lactam), 1710 (C=O of amide, C=O str), 1660
(C=O of quinazolinone), 1398 (C=N), 1237 (N–N), 767
1
(C–Cl). H NMR (400 MHz, DMSO-d6) d ppm : 1.24 (t,
3H, CH3), 2.52 (q, 2H, CH2), 2.52 (s, 2H, CH2), 4.45 (d,
J = 9.0, 1H, CH–Cl), 5.29 (d, J = 9.1, 1H, N–CH–Ar),
5.67 (s, 1H, NH), 7.26–7.45 (m, 12H, Ar–H), 8.40 (s, 1H,
NH–CO exchangeable). 13C NMR (400 MHz, DMSO-d6) d
ppm: 9.61 (CH2CH3), 28.42 (CH2CH3), 40.77 (C15), 60.34
(C17), 64.34 (C18), 126.56-150.25 (C1–C6, C10–C14, C19–
C24), 122.28–133.15 (C2–C6, C10–C11, C19–C22), 138.17
(C23), 139.72 (C24), 142.14 (C14), 147.76 (C1), 150.25
(C12–C13), 163.64 (C16), 164.25 (C8), 167.13 (C9), 171.96
(C7). Analysis for C26H23ClN6O3 (502.95). Calcd: C,
62.09; H, 4.61; N, 15.18%. Found: C, 61.51; H, 4.72; N,
11.69%. MS: m/z [502.15]?.
2-[(40-Oxo-30-chloro-20-{p-bromophenyl} azetidin-10-yla-
mino)-methyl]-3-[N-isonicotinamide-yl]-quinazoline-4-one
7k Yield, 63%; m.p., 315°C. IR (mmax in cm-1): 3347
(NH), 3099 (C–H aromatic), 2950 (C–H aliphatic), 1722
(C=O of b-lactam), 1654 (C=O of quinazolinone), 1635
(C=O of amide, C=O str), 1316 (C=N), 1211 (N–N), 743
(C–Cl), 695 (C–Br). 1H NMR (400 MHz, DMSO-d6) d
ppm : 2.34 (s, 2H, CH2), 4.58 (d, J = 9.0, 1H, CH–Cl),
5.69 (d, J = 9.1, 1H, N–CH–Ar), 5.72 (s, 1H, NH), 6.48-
7.57 (m, 12H, Ar–H), 8.76 (s, 1H, NH–CO exchangeable).
13C NMR (400 MHz, DMSO-d6) d ppm: 47.37 (C15), 62.54
(C17), 64.28 (C18), 123.08–133.15 (C2–C6, C10–C11, C19–
C23), 141.57 (C24), 142.16 (C14), 147.85 (C1), 150.89 (C12–
C13), 163.46 (C16), 164.19 (C8), 167.24 (C7), 167.46 (C9).
Analysis for C24H18ClBrN6O3 (553.80). Calcd: C, 52.05;
H, 3.28; N, 15.18%. Found: C, 51.86; H, 3.43; N, 15.34%.
MS: m/z [554.03]?.
In vitro evaluation of antitubercular activity
Drug susceptibility and determination of MIC of the test
compounds against Mycobacterium tuberculosis H37Rv
were performed by L. J. (Lowenstein and Jensen) MIC
method (Rattan, 2000) for the measurement of MIC. Stock
solutions of primary 1000, 500, 250 lg/ml and secondary
200, 100, 62.5, 50, 25, 12.5, 6.25, and 3.25 lg/ml dilutions
of each test compound in dimethylsulphoxide (DMSO)
were added liquid L. J. medium and then media were
sterilized by inspissations method.
A
culture of
123

2768
Med Chem Res (2012) 21:2762–2771
Mycobacterium tuberculosis H37Rv growing on L. J.
medium was harvested in 0.85% saline in bijou bottles.
These tubes were then incubated at 37°C for 24 h followed
by streaking of Mycobacterium tuberculosis H37Rv
(5 9 104 bacilli per tube). These tubes were then incubated
at 37°C. Growth of bacilli was seen after 12 days, 22 days
and finally 28 days of incubation. Tubes having the com-
pounds were compared with control tubes where medium
alone was incubated with Mycobacterium tuberculosis
H37Rv. The concentration at which no development of
colonies occurred or \20 colonies was taken as MIC
concentration of test compound. The standard strain
Mycobacterium tuberculosis H37Rv was tested with known
drug rifampicin and isoniazid. The data are shown in
Table 1.
synthesized by using commercially available isonicotinic
acid hydrazide. N-Chloroacetyl anthranilic acid 2 was
synthesized by the reaction of anthranilic acid 1 with
chloroacetylchloride in the presence of dry benzene. Fur-
ther the cyclization reaction with isonicotinic acid hydra-
zide in the presence of dry K2CO3, compound 2 yielded
2-Chloromethyl-3-[N-isonicotinamide-yl]-quinazolin-4-
one 3. Treatment of compound 3 with 99% hydrazine
hydrates afforded 2-hydrazinomethyl-3-[N-isonicotina-
mide-yl]-quinazoline-4-one 4. The structure of compound
4 was confirmed by elemental analysis and IR spectra
showing absorption band at 1255 cm-1 (N–N). Further the
absence of peak between 750 and 600 cm-1 (C–Cl) con-
firms the structure. Compound 4 on condensation reaction
with substituted benzaldehyde 5a–k in ethanol gave
2-benzylidenehydrazinomethyl-3-[N-isonicotinamide-yl]-
quinazolin-4-one, i.e. schiff bases 6a–k. IR spectra of these
compounds showed absorption band at 1612–1629 cm-1
for imine, i.e. (N=CH).1H NMR of these compounds
revealed the presence of single peak at d 7.88–8.36 for
(N=CH) and D2O exchangeable singlet at d 1.94–2.32 for
CH2-NH, while singlet at d 2.13–2.91 for CH2-NH were
observed. 13C-spectra further reveal the confirmation of the
Result and discussion
Chemistry
The synthetic protocol used to synthesize the title com-
pounds is outlined in Scheme 1. Compounds 7a–k was
Table 1 Minimal inhibition concentration (lg/ml) of 7a–k
Compound
R
Gram -ve organism
Gram ?ve organism
Fungal strain
Anti-tubercular activity
E.c. P.a. Kl.p S.t. S.a.
S.p.
B.s.
C.A. A.N.
A.C.
M. tuberculosis % Inhibition
(lg/ml)
7a
–H
200 125 200 200 250
100 200 250 250 200
250 250 500 250 500
150 150 200 200 100
250 250 100 500 500
250
250
500
125
500
500
250
250
200
250
200
0.5
100
50
100
250
200
100
500
250
250
250
250
100
200
–
1000 500
1000 500
500
500
500
98
99
97
99
98
99
97
97
98
97
97
98
99
–
7b
2-NO2
3-NO2
4-NO2
2-Cl
100
7c
1000 [1000 [1000 270
7d
500
200
250
250
500
200
[1000 [1000 50
7e
200
250
500
62.5
250
7f
4-Cl
50
100 100 100 500
1000
1000
1000
1000
7g
2-OH
4-OH
100 125 250 125 250
7h
250 250 250 250 200
[1000 [1000 250
250 200 259
7i
4-OCH3 500 500 62.5 500 125
7j
4-C2H5
200 500 250 125 200
62.5 200 500 100 200
1000 [1000 [1000 500
7k
4-Br
–
500
–
1000
–
500
–
100
40
0.20
–
Gentamycin
Ampicillin
Chloramphenicol
Ciprofloxacin
Norfloxacin
Nystatin
Greseofulvin
Rifampicin
Isoniazid
0.05
1
0.05
1
0.25
–
100 100 100 100 250
–
–
–
–
–
50
25
10
–
50
25
10
–
50
25
10
–
50
25
10
–
50
50
10
–
–
–
–
–
–
50
–
–
–
–
–
–
–
10
–
–
–
–
–
–
–
–
100
500
–
100
100
–
100
100
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
40
0.20
98
99
–
–
–
–
–
–
–
–
–
–
–
E.c., E. coli (MTCC 443); P.a., P. aeruginosa (MTCC 1688); Kl.p., Kl. pneumoniae (MTCC109); S.t., S. typhi (MTCC98); S.a., S. aureus
(MTCC 96); S.p., S. pyogenus (MTCC 442); B.s., B. subtilis (MTCC 441); C.A., C. albicans (MTCC 227); A.N., A. niger (MTCC 282); A.C., A.
clavatus (MTCC 1323); M. tuberculosis: Mycobacterium tuberculosis H37Rv (MTCC 200)
123

Med Chem Res (2012) 21:2762–2771
2769
O
N
COOH
COOH
O
C
a
b
H
N
N
N
NH2
NHCOCH2Cl
C
Cl
2
1
3
H2
c
O
N
O
C
H
N
N
N
H
C
N
NH2
H2
4
R
d
OHC
5a-k
O
O
C
R = -H, 2-NO2,
4-Cl, 4-NO2,
3-NO2,4-OH,
4-OCH3, 2-Cl,
4-C2H5, 4-Br,
2-OH
H
N
N
N
R
H
N
N
O
C
N
C
H
H2
6a-k
e
O
C
H
N
N
N
R
H
N
H
C
N
C
N
H2
7a-k
O
Cl
Scheme 1 Reagent and condition: (a) ClCH2COCl (2), pyridine, dry benzene, reflux, 5 h; (b) isonicotinic acid hydrazide (4), dry K2CO3,
benzene, reflux, 3 h; (c) N2H4, EtOH, reflux, 8 h; (d) gla. CH3COOH, EtOH, reflux, 8 h; (e) ClCH2COCl, TEA, dry benzene, reflux, 7 h
structures. The carbon of Schiff base (N=CH) appear at d
154.51–154.93 and carbonyl carbon of amide appear at d
167.10–167.57 confirm the structure. Treatment of com-
pounds 6a–k with chloroacetyl chloride in basic media
gives 2-[(40-oxo-30-chloro-20-phenylazetidin-10-ylamino)-
confirming its assigned structure. 13C spectra of these
compounds shows the peak at 52.34–62.83 for
d
(N=CH).Carbonyl carbon of b-lactam appear at d 167.58–
167.13. Figures 1 and 2 give the idea regarding numbering
system for 13C NMR spectra of compounds 3, 4, 6a–k, and
7a–k.
methyl]-3-[Nisonicotinamide-yl]-quinazolin-4-one
7a–
k. The structures assigned to 7a–k were supported by IR
spectra showing absorption bands at 1710–1790 cm-1
(C=O of monocyclic b-lactam), 1591–1710 cm-1 (NH–
CO), and 1305–1399 cm-1 (C=N of quinazolinone ring).
1H NMR of these compounds revealed the presence of
singlet at d 2.26–2.84 for (CH2–NH), doublet at d
4.45–5.87 (N–CH–Ar).Further the appearance of NH–CO
singlet at d 7.45–8.98 and CH–Cl doublet at d 4.45–4.93
Biological activity
From in vitro antibacterial activity data, it is confirmed that
compounds containing strong electron withdrawing, i.e. 7d
(4-nitro) exhibited excellent anti-bacterial activity against
the tested gram-positive microorganisms while compound
7f (4-chloro) exhibited excellent anti-bacterial activity
123

2770
Med Chem Res (2012) 21:2762–2771
O
7
O
7
10
12
10
11
12
13
O
O
3
6
3
6
14
14
H
N
9
H
N
4
5
4
5
N
C
9
N
N
C
9
N
2
1
2
1
8
8
11
13
H
N
N
C
NH2
N
C
Cl
H2
15
H2
15
3
4
Fig. 1 The numbering system of the compounds 3 and 4 for 13C NMR spectra
O
7
O
10
12
10
12
O
O
3
6
3
14
7
14
H
H
N
4
5
4
5
N
N
C
9
N
N
C
9
N
2
1
2
1
17
18
19
20
19
20
21
22
8
8
11
13
17
11
N
13
22
24
H
N
H
H
N
N
C
N
23
C
21
C
N
C
6
H2
15
H2
15
H
16
16
18
O
Cl
6a-k
7a-k
Fig. 2 The numbering system of the compounds 6a–k and 7a–k for 13C NMR spectra
against tested gram-negative strains. The compounds 7f (2-
nitro) and 7k (4-bromo) exhibited excellent activ-
ity(50–62.5 lg/ml), and compounds 7b (2-nitro) and 7g
(2-hydroxyl) displayed good activity (100 lg/ml) against
E. coli, while compounds 7a, 7f, and 7g displayed activity
in range of (100–125 lg/ml) against P. aeruginosa, while
compounds 7e, 7f displayed (100 lg/ml) and 7i displayed
better (62.5 lg/ml) against Kl. pneumoniae, while other
compounds showed moderate to good activity (100–
250 lg/ml) others against gram-positive and gram-negative
strains as compared to standards. The evaluation of the in
vitro antifungal activity demonstrated that compounds 7e
(2-chloro) and 7i (4-OCH3) displayed highest activity
against the fungal strains tested, while compounds 7f
(4-chloro)and7g (2-hydroxyl)showedsomewhatlessactivity
against C. albicans compared to compounds 7e and 7i.
But overall, all the compounds have shown significant
antibacterial and antifungal activities. In general, the order
of antibacterial activity of the substituent at the aryl ring is
Cl [ NO2 [ Br [ OCH3 [ H=OH = C2H5 and also para-
isomer [ meta-isomer [ ortho-isomer is the order for
better activity. The results of antibacterial and antifungal
activity are summarized in Table 1.
(50–62.5 lg/ml) which is attributed due to 4-chloro,
whereas other compounds displayed moderate to good
activity with 97–99% Inhibition at the concentration of
(100–500 lg/ml). Thus, further developmental studies to
acquire more information about structure–activity rela-
tionships are in progress in our laboratories. The results of
antitubercular screening are summarized in Table 1.
Conclusion
A series of new analogs of azetidinyl-3-quinazolin-4-one
hybrid derivatives were synthesized by introduction of
isonicotinic acid hydrazide to quinazolin-4-one nucleus
and assessed for their antimicrobial activities. Modification
of the substituents on phenyl ring with various electron
releasing and electron withdrawing substituents influenced
the activity. It is important to point out that activity is not
affected by electronic properties of the substituents. The
antibacterial activity data indicates that the analogs with
halogen and nitro substituents emerged as promising anti-
microbials showing better to moderate activity while ana-
logs bearing chloro and methoxyl substituent showed better
antifungal activities. It was also observed that the prom-
ising antimicrobials have proved to be better antitubercu-
lars. Specially, compounds 7d and 7f due to their better
activity against H37Rv strain, are the best choice for the
preparation of new derivatives in order to improve antitu-
bercular activity in future.
The encouraging results from the antibacterial and
antifungal studies impelled us to go for preliminary
screening of synthesized compounds against Mycobacte-
rium tuberculosis H37Rv which is summarized in Table 1.
Compound 7d containing 4-nitro substituent showed better
activity (50 lg/ml) and compound 7f showed good activity
123

Med Chem Res (2012) 21:2762–2771
2771
Acknowledgment The author (J.P. Raval) wishes to express his
thanks to Chairman-(CVM), Charutar Vidya Mandal, Director-SI-
CART & Director-ARIBAS for providing necessary research facili-
ties. Dr. Dhanji Rajani, Microcare laboratories, Surat for extending
help for assessment of biological activity. We are also thankful to
Mr. Priyakant R. Raval & Dr. Kishor R. Desai, Director, Shri
C. J. Bhakta Insititute of Biotechnology, Uka—Tarsadia University,
Bardoli for moral and research advice.
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