A microwave-assisted and heteropolyacids-catalysed cyclocondensation reaction for the synthesis of 4(3H)-quinazolinones

Article abstract of DOI:10.3390/molecules13040779

We have investigated a microwave-assisted synthesis of 4(3H)-quinazolinones by condensation of anthranilic acid, orthoesters (or formic acid) and substituted anilines, using Keggin-type heteropolyacids (H₃PW ₁₂O₄₀·13H

Full text of DOI:10.3390/molecules13040779

Molecules 2008, 13, 779-789
molecules
ISSN 1420-3049
© 2008 by MDPI
www.mdpi.org/molecules
Full Paper
A Microwave-Assisted and Heteropolyacids-Catalysed
Cyclocondensation Reaction for the Synthesis of
4(3H)-Quinazolinones
Karima Ighilahriz 1, Baya Boutemeur 1, Fariza Chami 2, Cherifa Rabia 2, Maâmar Hamdi 1 and
Safouane M. Hamdi 3,*
1
Laboratoire de Chimie Organique Appliquée (Equipe Hétérocycles Associée CRAPC). Faculté de
Chimie. Université des Sciences et de la Technologie Houari Boumediène. BP 32, El-Alia. 16111
Bab-Ezzouar. Alger, Algeria
2
Laboratoire de Chimie du Gaz Naturel. Faculté de Chimie. Université des Sciences et de la
Technologie Houari Boumediène. BP 32, El-Alia. 16111 Bab-Ezzouar. Alger, Algeria
3
Laboratoire de Biochimie-Purpan, Institut Fédératif de Biologie, CHU Toulouse 330, Avenue de
Grande-Bretagne – F- 31059 Toulouse cedex 9, France
* Author to whom correspondence should be addressed; E-mail: safouane.hamdi@toulouse.inserm.fr;
Tel:+33 5 67 69 03 76; Fax:+33 5 67 69 03 77
Received: 6 February 2008; in revised form: 28 March 2008 / Accepted: 28 March 2008 / Published:
3 April 2008
Abstract: We have investigated a microwave–assisted synthesis of 4(3H)–quinazolinones
by condensation of anthranilic acid, orthoesters (or formic acid) and substituted anilines,
using
Keggin-type
heteropolyacids
(H3PW12O40·13H2O,
H4SiW12O40·13H2O,
H4SiMo12O40·13H2O or H3PMo12O40·13H2O) as catalysts. We found that the the use of
H3PW12O40·13H2O acid coupled to microwave irradiation allows a solvent-free, rapid (~13
min) and high-yielding reaction.
Keywords: 4(3H)–Quinazolinones, heteropolyacids, microwave irradiation, solvent-free
synthesis

Molecules 2008, 13
780
Introduction
The quinazolinone core and its derivatives form an important class of compounds, as they are
present in a large family of products with broad biological activities. They generally display useful
therapeutic and pharmacological properties such as anti-inflammatory, anti-convulsant, anti-
hypertensive and antimalarial activity [1-4]. Moreover, the 4(3H)–quinazolinone moiety is found in
several bioactive natural products [5,6]. For these reasons their synthesis has received considerable
attention. Several groups have reported conventional preparation methods which require reflux for
several hours and the use of large volumes of solvent [7,8]. Recently, however, more interest has been
focused on “dry media” synthesis and particularly on solvent free procedures using microwave
irradiation [9-15, reviewed in 13]. Of interest, quinazolinones were recently prepared using various
catalysts such as Yb(OTf)3, Bi(TFA)3-FeCl4, silica gel/FeCl3, Nafion-H (a perfluorinated resin-
supported sulfonic acid) and La(NO3)3·6H2O [16-21].
The Keggin-type heteropolyacids (HPAs) are believed to have extensive prospects of application
in synthesis chemistry since their acidity strength is higher than that of both mineral and Lewis acids.
Moreover, they are easy to handle, non-volatile and non-explosive. Heteropolyacids compounds such
as H3PWI2O40 are known to be effective catalysts for various kinds of acid-catalyzed reactions [21-24]
and we recently reported the first microwave-assisted synthesis of calix[4]resorcinarenes using
aldehydes and resorcinol and catalyzed by H3PWI2O40 [25]. However, whether microwave irradiation
and the use of HPA as catalysts improves the synthesis of 4(3H)-quinazolinones has not been
investigated, to the best of our knowledge. We then tested several HPAs (abbreviated henceforth as
XM12, where X = P or Si and M = W or Mo) in the synthesis of 4(3H)–quinazolinones from
condensation with anthranilic acid, aniline and ortho esters (or formic acid) at reflux and under
microwave irradiation (Scheme 1).
Scheme 1. Synthesis of 4(3H)–quinazolinones by cyclocondensation of anthranilic acid
(1), aniline (2) and orthoester (or formic acid) in presence of HPA as catalyst.
O
O
Ph
HPA
OH
N
PhNH2
or
HC(OR)3
+
+
HCO2H
NH
2
N
1
2
3
4a
Results and Discussion
4(3H)–Quinazolinone synthesis in the presence of orthoesters (R= Me, Et) or formic acid was first
carried out at reflux or under microwave irradiation, respectively, with toluene or 2-ethoxyethanol as
solvent. As shown in Table 1, yields of 4(3H)–quinazolinones depended on the experimental
procedure, the nature of reactants as well as that of catalysts.

Molecules 2008, 13
781
Table 1. One–pot synthesis of 3-phenyl-4(3H)-quinazolinone from anthranilic acid,
aniline and ortho esters (or formic acid) catalysed by various HPA.
Microwave Irradiationc
With solventd
Solvent-free
Yield (%)e T(°C)g Yield (%)e T (°C)g
Conventional
Heatingb
Yield (%)e
Catalysta
Reactant
HC(OCH3)3
HC(OC2H5)3
HCO2H
70
75
55
63
68
48
54
56
40
43
49
36
57
70
130
126
-
70
75
67
65
68
60
65
65
56
60
60
52
163
166
165
160
164
165
156
164
163
155
165
164
PW12
SiW12
PMo12
f
-
HC(OCH3)3
HC(OC2H5)3
HCO2H
48
55
130
125
-
f
-
HC(OCH3)3
HC(OC2H5)3
HCO2H
43
55
132
127
-
f
-
HC(OCH3)3
HC(OC2H5)3
HCO2H
47
50
135
128
-
SiMo12
f
-
a
catalyst amount: 1.2 mol%
b
c
with 25 mL of toluene at reflux [120 min, T(°C)= 110]
microwave irradiation was carried out in two stages: first, activation for 3 min at 300 watts and
then, 10 min at 450 watts
5 mL of 2-ethoxyethanol
isolated yield
d
e
f
invalid result
g
temperature measurement by IR-thermometer
Compared to the conventional method, microwave activation in the presence of solvent led to
lower yields, whereas activation without solvent afforded equivalent or slightly increased yields. It
should be noted, however, that, in the latter case, the reaction time was ten-fold shorter (13 min for
microwave irradiation versus 120 min for conventional heating). Interestingly, when formic acid was
used as reactant, the microwave-assisted reactions always gave higher yields than the conventional
method. Besides experimental procedure and reactants, the 4(3H)–quinazolinone yields also depended
on the nature of the heteroatom (P, Si) and the metal atom (W, Mo) of the HPAs (Table 1). Hence, W
compounds were more efficient than Mo compounds, whereas P-based HPAs led to better yields than
those containing Si. Overall, the yields decreased in the following order: PW12>SiW12>PMo12> SiMo12
which is, strikingly, the same order of their acidic strengths [22]. These results suggest that the higher
the acidity of the HPA catalysts, the higher the yield of microwave- assisted synthesis of 4(3H)–
quinazolinones. In subsequent experiments, we choose the PW12 catalyst for its better catalytic
performance and examined the impact of various orthoesters/anthranilic acid ratios on reaction yields
(Scheme 1). Results obtained under solvent–free conditions and microwave irradiation are reported in
Table 2. For both HC(OC2H5)3 and HC(OCH3)3, yields increased and reached a peak for ortho
esters/anthranilic acid ratios of 1.4:1 before declining. However, with the aforementioned experimental
conditions, HC(OC2H5)3 gave higher yields than HC(OCH3)3 (77% versus 63% at the peak).

Molecules 2008, 13
782
Table 2. Effect of ortho ester/anthranilic acid ratios on 3-phenyl-4(3H)-quinazolinone
(4a) yield in the presence of PW12.
HC(OCH3)3
HC(OC2H5)3
Yield of 4a (%)b
Substrate ratio a
Yield of 4a (%)b
T(°C)c
163
T (°C)c
166
1.0 / 1
1.2 / 1
1.4 / 1
1.6 / 1
1.8 / 1
2.0 / 1
42
62
66
77
61
72
56
48
160
162
63
160
168
46
157
166
45
163
170
44
165
176
a ortho ester/anthranilic acid ratio
b solvent-free conditions and microwave irradiation as described in Table 1
c temperature measurement by IR-thermometer
In a third step, a wide range of structurally varied substituted anilines 2, anthranilic acid (1) and
triethyl orthoformate (3) were used in the presence of a catalytic amount (1,2 mol%) of PW12 under
microwave irradiation and solvent-free conditions (scheme 2). Results are summarized in Table 3.
Scheme 2. One-pot synthesis of 4(3H)–quinazolinones under solvent free conditions,
microwave-irradiation and PW12 mediated-catalysis with anthranilic acid (1), various
substituted anilines (2a-j) and triethyl orthoformate (3).
O
O
Ar
OH
PW12
N
ArNH2
+
HC(OC2H5)3
+
NH
2
N
1
2a-j
3
4a-j
Table 3. Impact of aniline structure on reaction yield.
ArNH2 (2a-g)
C6H5
Products Yield (%)
mp (°C)
139
lit. mp (°C)a
T (°C)b
168
4a
4b
4c
4d
4e
4f
77
80
80
65
55
60
50
45
30
35
139
194
147
195
182
186
-
4-MeOC6H4
4-MeC6H4
3-MeOC6H4
4-ClC6H4
194
132
147
133
159
130
181
142
4-BrC6H4
186
140
2,4-Cl2C6H3
3,4-Cl2C6H3
2,6-Cl2C6H3
2,5-Cl2C6H3
4g
4h
4i
230-236
160-166
252
145
-
141
-
148
4j
145
-
146
a literature melting points [12, 13, 16]
b temperature measurement by IR-thermometer

Molecules 2008, 13
783
In all cases, the three components of the reaction proceeded rapidly to afford the corresponding
4(3H)-quinazolinones 4a-j but we noticed a significant difference in reaction yields. Indeed, anilines
structure had an obvious impact on the obtained yields since all anilines having electron-donating
substituents reacted very well, and gave good yield in a few minutes. It can be inferred from these
observations that electron-donating groups (such as methoxy and methyl) are beneficial for the
reaction owing to the increased electron density that they induce in the aromatic system. By contrast,
electron-withdrawing groups (such as chloro and bromo) are unfavourable for the transformation.
Another interesting result is that the reaction with para-electron-donating substituted anilines (4-
MeO), was more efficient than that with meta-electron-donating substituted anilines (3-MeO).
Moreover, the condensation yield with dichloroanilines was lower than that with monochloroaniline
(Table 3). Thus, the efficiency of the microwave-assisted and solvent-free condensation of anthralinic
acid 1 with triethyl ortho formate 3 and aniline derivatives 2a-j is heavily affected by the electronic
nature and the number and the position of substituents on aniline. Analysis of the reaction data (Tables
1 and 2) obtained from model compounds 2 and 3 leads to the following observations:
(a) Comparison between conventional heating and microwave irradiation revealed a specific
and strong microwaves effect since, under conventional heating the reaction occurred in a
very limited extension. After 60 min, thermal reaction did not allow to produce any
quinazolinones 4, the optimal yields were reached after 120 min of heating. By contrast,
quinazolinones 4 were obtained after only 13 min of microwave irradiation.
(b) In microwave irradiation, thermal energy is generated in situ due to the interaction of polar
molecules or ionic species with the electric field. So, the power range was set to 450 W, in
order to avoid an overheating that may induce products degradation.
(c) A crucial role for acid during the cyclocondensation step cannot be excluded since we
obtained very low yields in all reactions carried without acid.
(d) The reactions performed under solvent-free conditions allowed the observation of
microwave effects, i.e. higher yields and higher measured temperatures.
Besides the efficient energy input that microwaves can provide to the reaction mixtures, a chemical
activation effect cannot be discounted. During the irradiation, there is a total or partial alignment of
dipolar molecules and/or ionic species with the direction of the electrical field. Such an alignment may
then favor interactions between reactants and may lead to shorter and more efficient reactions. Our
observation that electron-donating or -withdrawing substituents on anilines have an impact on reaction
yields (cf. Table 3) supports the above hypothesis, since these substituents can modify the aniline's
dipolar moments and consequently, may affect their behavior in the electrical field.
Finally, regarding the reaction mechanism, we propose that the three–component synthesis of
4(3H)-quinazolinones can proceed via three pathways, namely A, B and C (Scheme 3). Pathway A
may involve the intermediate imidic ester 5 stabilized by HPA. Then, the imidic ester may be very
prone to react with an amine, thus leading to the amidine intermediate 7 (path A). Alternatively, it may
form the benzoxazinone 9 through loss of ethanol and cyclocondensation (path C). The benzoxazinone
9 can lead the intermediate 10, which rapidly cyclizes to yield quinazolones 4, as previously reported
[10]. Path B may first involve the imidic ester 6, which condenses with anthranilic acid to give the
amidine 7. The latter may then cyclize to form the quinazolinone 4. The accelerating role of

Molecules 2008, 13
784
microwaves on these reaction pathways may also be explained by a thermal effect as well as the
chemical activation discussed above. As an example, the polarization of 7 and the supposed formation
of 8 (Scheme 3) might be favored by microwave irradiation.
Scheme 3. Proposed mechanism for the cyclocondensation reaction.
O
OH
+
+
HC(O Et)3
Ar NH2
NH
2
2
3
1
HPA
HPA
O
path A
path B
O
N
Ar
N
H
OH
OH
+
OEt
H
NH
2
6
OEt
Ar NH2
path A
Ar NH2
5
path C
O
O
OH
O
Ar
N
N
H
N
9
7
Ar NH2
O
O
H
O
Ar
Ar
N
N
-
o
H
O
Ar
N
+
N
H
H
N
C
N
H
H
10
8
4
Conclusions
We developed a single-step and efficient synthesis of 4(3H)-quinazolinones using anthranilic acid,
ortho esters and substituted anilines under PW12-mediated catalysis, microwave irradiation and
solvent-free conditions. Mildness of the catalysts, avoidance of solvents, short reaction times (13 min)
and good yields (80%) are the outstanding advantages of the present protocol.
Experimental
General
Pure heteropolyacids HnXM12O40 (PM12) were prepared by the standard method involving the
synthesis of the corresponding sodium salt and the extraction of acid by diethyl ether and its

Molecules 2008, 13
785
purification by crystallization in water at 4°C [26]. Anthranilic acid was purchased from Sigma.
Amines, toluene and 2-ethoxyethanol were purchased from Aldrich. All melting points were measured
on a Stuart Scientific SMP3 apparatus fitted with a microscope and uncorrected. The IR absorption
spectra (KBr disks, cm-1) were measured on a Nicolet Magna 550 series II IR Spectrophotometer. 1H-
NMR (300.13 MHz) and 13C-NMR (75.47 MHz) spectra were recorded in deuterated chloroform
(CDCl3) on a Bruker DRX 300 spectrometer using tetramethylsilane (TMS) as an internal reference
and results are expressed as δ values (ppm). Mass spectra were recorded on a Nermag R 10-10C
quadruple mass spectrometer at 70 eV. All the compounds gave satisfactory elemental analyses.
The multimode microwave reactor (a modified microwave oven Candy MGA 20M) has a single
magnetron (2450 MHz) unt with a maximum delivered power of 800W. Experiments were carried out
in a Pyrex reactor fitted with a condenser. During experiments, temperature was monitored with an
external infra-red thermometer (Flashpoint FZ400). Our modifications to a domestic microwave oven,
adopted since 1992, are similar to those described, currently, for microwave chemistry experiments
[27]. In a typical design, a hole was drilled for a condenser tube in the oven top. External steel tube of
the same diameter (~12 cm long) was welded to the hole in order to eliminate possible microwave
leakage. The microwave equipment operates within the safety limits prescribed: accepted limit on the
safe stray leakage of the microwave power density is 10mW/cm2 at 2450 MHz measured at a 50 mm
distance from the equipment (Microwave Leakage Detector). The apparatus has been adapted for
laboratory applications with an external reflux condenser, multi-limb vacuum receivers and Dean-
Stark trap. (Figure 1)
Figure 1. Fractional separations in a modified microwave oven (with a freezing bath and
under vacuum).
General Procedure for the preparation of 4(3H)-quinazolinones 4a-j
Method I (conventional heating): The synthesis of 4(3H)-quinazolinones from anthranilic acid (10
mmoles), amine (10 mmol) and formic acid or ortho esters (14 mmol) in presence of a catalytic

Molecules 2008, 13
786
amount of heteropolyacids (1. 2 mol%) was carried out under reflux in toluene (25 mL) for 2 h. The
obtained solid was crystallized in ethanol after washing with water to eliminate any catalyst residue.
Method II (microwave irradiation): The synthesis of 4(3H)-quinazolinones from anthranilic acid (10
mmol), amine (10 mmol) and formic acid or orthoesters (14 mmol) in the presence of a catalytic
amount of heteropolyacids (1. 2 mol%) and 2-ethoxyethanol (5 mL) was carried out under microwave
irradiation. The power was initially set to 300 W for 3 min, then it was increased to 450 W for 10 min.
The obtained solid was crystallized in ethanol after washing with water to eliminate any catalyst
residue.
Method III (microwave irradiation without solvent): is the solvent-free version of method II.
3-Phenyl-4(3H)-quinazolinones (4a). IR νmax: 1699, 1598 and 1463; 1H-NMR: δ = 8.34 (d, J =7.6 Hz,
13
1H), 8.16 (s, 1H), 7.72-7.78 (m, 2H), 7.51 (t, J =7.31 Hz, 1H) and 7.28-7.36 (m, 5H); C-NMR: δ =
160.7, 147.1, 147.2, 136.3, 135.2, 134.6, 129.9, 128.6, 128.1, 127.4, 127.0 and 122.6; GC/MS: m/z
(%) = 222.2 (M+, 100), 223.2 (M+1, 15); Anal. Calcd. for C14H10N2O: C, 75.66; H, 4.54; N, 12.60; O,
7.2. Found: C, 75.60; H, 4.44; N, 12.52.
3-(4-Methoxyphenyl)-4(3H)-quinazolinone (4b). IR νmax: 1699, 1598, 1463;1H-NMR: δ = 8.28 (d, J =
7.6 Hz, 1H), 8.12 (s, 1H), 7.68-7.72 (m, 2H), 7.42 (t, J =7.3 Hz, 1H), 7.29 (d, J = 7.6 Hz, 2H), 7.15 (d,
J = 7.7 Hz, 2H) and 3.71 (s, 3H); 13C-NMR : δ = 161.2, 148.3, 146.2, 134.3, 133.2, 131.5, 128.1,
127.1, 126.2, 125.1, 124.8, 124.2, 122.1 and 55.9; GC/MS : m/z (%) = 252.2 (M+, 100); 253.2 (M++1,
14); Anal. Calcd. for C15H12N2O2: C, 71.42; H, 4.79; N, 11.10; O, 12.68. Found: C, 75.63; H, 4.71; N,
11.03.
1
3-(4-Methylphenyl)-4(3H)-quinazolinone (4c). IR νmax: 1690, 1603, 1457; H-NMR: δ = 8.29 (d, J =
7.6 Hz, 1H), 8.11 (s, 1H), 7.69-7.71 (m, 2H), 7.40 (t, J = 7.2 Hz, 2H), 7.16 (d, J = 7.6 Hz, 2H), 7.28 (d,
J = 7.6 Hz, 2H) and 2.26 (s, 3H); 13C-NMR: δ = 159.9, 147.3, 146.2, 134.3, 133.2, 131.5, 128.1,
127.1, 126.2, 125.1, 124.8, 124.1, 122.1 and 20.5; GC/MS: m/z (%) = 236.2 (M+ , 100); 237.2 (M++1,
14); Anal. Calcd. for C15H12N2O: C, 76.25; H, 5.12; N, 11.86; O, 6.95. Found: C, 76.28; H, 5.18; N,
11.70.
3-(3-Methoxyphenyl)-4(3H)-quinazolinone (4d). IR νmax: 1692, 1605, 1456; 1H-NMR: δ = 8.29 (d, J =
7.6Hz, 1H), 8.13 (s, 1H), 7.66-7.73 ( m, 2H), 7.42 (t, J =7.3Hz, 1H), 7.23-7.35 (m, 4H) and 3.71 (s,
3H); 13C-NMR: δ = 162.2, 148.3, 146.2, 134.3, 133.2, 131.4, 128.1, 127.1, 126.2, 125.1, 124.8, 124.2,
122.1 and 56.8; GC/MS: m/z (%) = 252.2 (M+, 100); 253.2 (M++1, 14); Anal. Calcd. for C15H12N2O2:
C, 71.42; H, 4.79; N, 11.10; O,12.69. Found: C, 71.46; H, 4.75; N, 11.13.
1
3-(4- Chlorophenyl)-4(3H)-quinazolinone (4e). IR νmax: 1696, 1601, 1462; H-NMR: δ = 8.33 (d, J =
7.5 Hz, 1H), 8.13 (s, 1H), 7.68-7.71 (m, 2H), 7.48 (t, J = 7.3 Hz, 1H), 7.38 (d, J = 7.6 Hz, 2H) and 7.25
(d, J = 8.6 Hz, 2H); 13C-NMR: δ= 160.2, 148.8, 146.6, 136.1, 135.2, 134.6, 132.7, 130.5, 128.3, 127.2,
127.8 and 125.1; GC/MS : m/z (%) = 256.0 (M+ , 100); 257.0 (M++2); Anal. Calcd. for C14H9 ClN2O:
C, 65.51; H, 3.53; Cl, 13.81; N, 10.91; O, 6.23. Found: C, 65.50; H, 3.41; N, 11.13.

Molecules 2008, 13
787
1
3-(4-Bromophenyl)-4(3H)-quinazolinone (4f). IR νmax: 1692, 1605, 1456; H-NMR: δ = 8.43 (d, J =
13
8.6 Hz, 1H), 8.12 (s, 1H) and 7.95-7.21 (m, 7H); C-NMR: δ = 160.0, 145.3, 134.6, 133.4, 132.7,
131.4, 130.7, 128.5, 128.1, 127.7, 127.6, 127.6 and 127.1; GC/MS : m/z (%) = 302, 300 (M+ ); Anal.
Calcd. for C14H9 BrN2O: C, 55.84; H, 3.01; Br, 26.53; N, 9.30.
1
3-(2,4-Dichlorophenyl)-4(3H)-quinazolinone (4g). IR νmax: 1679, 1610, 1452; H-NMR: δ= 8.13 (d, J
= 7.6 Hz, 1H), 7.95 (s, 1H), 7.85-7.66 (m, 2H), 7.53 (t, J = 7.3 Hz, 1H), 7.38 (d, J = 7.6 Hz, 2H) and
13
7.25 (d, J = 8.6 Hz, 1H); C-NMR: δ= 164.2, 162.8, 147.6, 136.3, 134.2, 132.6, 130.7, 129.5, 128.3,
127.2, 127.8, 124.1 and 123.1; GC/MS : m/z (%) = 291.13 (M+ ); Anal. Calcd. for C14H8 Cl2N2O: C,
57.76; H, 2.77; , Cl, 24.36; N, 9.62.
3-(2,5-Dichlorophenyl)-4(3H)-quinazolinone (4h). IR νmax: 1673, 1604, 1450; 1H-NMR: δ = 8.43 (d, J
= 7.6 Hz, 1H), 8.13 (s, 1H), 7.69-7.72 (m, 2H), 7.50 (t, J = 7.3 Hz, 1H), 7.38 (d, J = 7.6 Hz, 2H), 7.25
13
(d, J = 8.6 Hz, 2H); C-NMR (CDCl3): δ = 165.2, 163.1, 148.8, 141.6, 134.0, 133.1, 130.2, 129.7,
128.3, 128.2, 126.2, 125.7, 123.1 and 123.1; Anal. Calcd. for C14H8 Cl2N2O: C, 57.76; H, 2.77; , Cl,
24.36 ; N, 9.62.
1
3-(2,6-Dichlorophenyl)-4(3H)-quinazolinone (4i). IR νmax: 1660, 1618, 1456; H-NMR: δ = 8.23 (d, J
= 7.6 Hz, 1H), 8.13 (s, 1H), 7.69-7.72 (m, 2H), 7.50 (t, J = 7.3 Hz, 1H), 7.38 (d, J = 7.6 Hz, 2H) ; 7.25
(d, J = 8.6 Hz, 2H); 13C-NMR: δ= 165.2, 163.3, 148.4, 136.6, 133.2, 128.6, 127.6, 127.5, 127.2, 127.0,
126.9 and 123.1; Anal. Calcd. for C14H8 Cl2N2O: C, 57.76; H, 2.77, Cl, 24.36; N, 9.62.
1
3-(3,4-Dichlorophenyl)-4(3H)-quinazolinone (4j). IR νmax: 1687, 1625, 1461; H-NMR: δ = 8.23 (d, J
= 7.6 Hz, 1H), 8.18 (s, 1H), 7.69-7.72 (m, 2H), 7.50 (t, J = 7.3 Hz, 1H), 7.38 (d, J = 7.6 Hz, 2H) and
13
7.25 (d, J = 8.6 Hz, 2H); C-NMR: δ = 165.2, 163.3, 147.8, 137.7, 134.4, 133.2, 130.7, 130.0, 128.6,
127.1, 127.0, 122.2, 122.1 and 119.9; Anal. Calcd. for C14H8 Cl2N2O: C, 57.76; H, 2.77; Cl, 24.36; N,
9.62.
References and Notes
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