Saccharomyces cerevisiae catalyzed one pot synthesis of isoindolo[2,1-a]quinazoline performed under ultrasonication

Article abstract of DOI:10.1016/j.molcatb.2013.01.024

An efficient and simple one pot method has been developed for the synthesis of isoindolo[2,1-a]quinazolines using Saccharomyces cerevisiae (baker's yeast) as a whole cell biocatalyst at room temperature. The synergetic effect of baker's yeast and ultrasound irradiation has been discussed.

Full text of DOI:10.1016/j.molcatb.2013.01.024

Journal of Molecular Catalysis B: Enzymatic 90 (2013) 70–75
Contents lists available at SciVerse ScienceDirect
Journal of Molecular Catalysis B: Enzymatic
journal homepage: www.elsevier.com/locate/molcatb
Saccharomyces cerevisiae catalyzed one pot synthesis of
isoindolo[2,1-a]quinazoline performed under ultrasonication
Jemin R. Avalani, Devji S. Patel, Dipak K. Raval∗
Department of Chemistry, Sardar Patel University, Vallabh Vidyanagar 388120, Gujarat, India
a r t i c l e i n f o
a b s t r a c t
Article history:
An efficient and simple one pot method has been developed for the synthesis of isoindolo[2,1-
a]quinazolines using Saccharomyces cerevisiae (baker’s yeast) as a whole cell biocatalyst at room
temperature. The synergetic effect of baker’s yeast and ultrasound irradiation has been discussed.
© 2013 Elsevier B.V. All rights reserved.
Received 24 November 2012
Received in revised form 10 January 2013
Accepted 27 January 2013
Available online 4 February 2013
Keywords:
Baker’s yeast
Ultrasound
Multicomponent synthesis
Biocatalysis
Enzymes
1. Introduction
array of structurally diverse isoindoles, it is an important sub-
structure of various biologically active natural products such as
Biocatalyzed reactions in organic media have become a popular
approach with several reports appearing in the literature [1–4]. The
use of aqueous media for such transformations is not desirable as
most of the organic substrates are insoluble in water [5]. Biocatal-
ysis in organic solvents have several advantages; high solubility
of organic substrates to perform the reaction which is compli-
cated in aqueous media, easy isolation of products and insolubility
of enzymes in organic solvents which permits their easy recov-
ery and reuse [6]. Baker’s yeast is known to play vital role in
functional group conversion and also been reported to catalyze
organic transformations effectively such as reduction [7–9], hydrol-
ysis [10], oxidation [11] and condensation [12]. Baker’s yeast has
been extensively used to carry out various organic reactions and can
be used in the synthesis of various heterocyclic compounds such as
polyhydroquinolines [13], 4H-pyrans [5], isoxazolines [14] and 1,4-
dihydropyridines [15]. Baker’s yeast is also reported to show high
activity and enantioselectivity in aqueous/organic biphasic systems
[16–18]. Recently Silva et al. have reported asymmetric reduction of
(4R)-(−)-carvone catalyzed by Baker’s yeast in mono- and biphasic
systems [19].
bhimamycin C, and bhimamycin D which display bioactivities
against human ovarian cancer cell lines and are also EP4 recep-
tor agonists in the treatment of pain [20]. It exhibits variety of
biological properties such as anti-neoplastic, antiviral [21], anti-
malarial [22], antitumor [23], and antimicrobial activities [24]. The
unique scaffold and pharmacological properties associated with
quinazoline nucleus attracted the attention of chemists toward
the syntheses of various types of useful compounds in medicinal
chemistry. It possesses wide variety of activities like antibacte-
rials [25], antivirals [26,27], antitumorals [28], and many other
therapeutic activities [29]. Additionally fused indole derivatives
such as indolocarbazoles [30,31], indoloisoquinolines [32–34],
indoloquinolines [35–38], and indoloquinazolines [39–41] exhibit
a number of remarkable pharmacological properties. Among them,
isoindolo[2,1-a]quinazoline showed high cytotoxic activity against
a wide range of human cancer cells and at the molecular level are
inhibitors of tubulin polymerase and topoisomerase I. This confirms
the prospects of using them as anticancer drugs [42,43] and TNF-
␣ inhibition against various inflammatory disorders [44]. Recently
the syntheses of these derivatives are reported using camphor sul-
phonic acid; p-toluenesulphonic acid and Montmorillonite K10 as
the heterogeneous catalyst by conventional method with longer
reaction time [44].
Isoindoles are ubiquitous structural motifs of the most com-
mon heterocyclic compounds found in both natural products
and biologically active compounds. Due to the existence of an
Ultrasound irradiation is a powerful technique, which is being
used frequently to accelerate organic transformations [45–48]. It
is one of the most widely used laboratory methods for the disrup-
tion of cells of baker’s yeast for the fast release of enzymes [49].
∗
Corresponding author. Tel.: +91 2692226856x211.
E-mail addresses: dipanalka@yahoo.com, dk raval@spuvvn.edu (D.K. Raval).
1381-1177/$ – see front matter © 2013 Elsevier B.V. All rights reserved.
http://dx.doi.org/10.1016/j.molcatb.2013.01.024

J.R. Avalani et al. / Journal of Molecular Catalysis B: Enzymatic 90 (2013) 70–75
71
The remarkable features of ultrasound irradiation are decrement in
reaction time, high efficiency, formation of pure product and waste
minimization compared to conventional methods [50].
(m/z, %): 295.0 (100), 276.9 (41), 252.0 (5), 236.0 (11). Anal. Calcd.
for C17H14N2O3 (294.23): C, 69.38; H, 4.79; N, 9.52. Found C, 69.22;
H, 4.96; N, 9.70.
As a part of our ongoing endeavor for the construction of vari-
ous heterocyclic compounds [51–59], herein we document the role
of baker’s yeast under ultrasound at room temperature to afford
isoindolo[2,1-a]quinazolines (Scheme 1).
3. Result and discussion
A series of experiments were performed with the model reac-
tion of isatoic anhydride 1, 2-carboxy benzaldehyde 2, and benzyl
amine 3 in the presence of baker’s yeast in organic medium under
sonication at 30 ◦C.
2. Experimental
2.1. Materials and instruments
3.1. Effects of solvents under ultrasound irradiation
The following chemicals were used as received. Isatoic anhy-
dride (96%), 2-carboxy benzaldehyde (97%) and amines (≥96%)
were purchased from Sigma Aldrich. All organic solvents were
obtained from commercial sources and were of analytical grade.
Melting points were determined using ␮ThermoCal10 (Analab Sci-
entific Pvt. Ltd.) melting point apparatus and are uncorrected.
Progress of the reaction was monitored by thin layer chromatogra-
phy on Merck’s silica plates. 1H and 13C NMR spectra were recorded
on Bruker Avance 400 MHz instruments using TMS as internal
standard. Mass spectra were recorded on Shimadzu LCMS 2010
mass spectrometer. IR spectra were recorded on a FTIR Perkin Elmer
To understand the effect of reaction medium on the rate
and yield of the reaction, the model reaction was performed in
various solvents like methanol, ethanol, tetrahydrofuran (THF),
dichloromethane (DCM), acetonitrile, dimethyl formamide (DMF),
Dimethyl acetamide, water and phosphate buffer (pH 6.0). The
results are summarized in Table 1.
It is clear from Table 1 that the reaction performed without
ultrasound afforded comparatively lower yields even after longer
reaction time under ambient condition. When water and phosphate
buffer were employed as the reaction medium, the starting mate-
rials were recovered (Table 1, entries 10 and 11). It might be due
to insolubility of substrates in aqueous medium. In all cases, the
reaction times are strikingly shorter and the yields of the products
are higher under sonication. It was noted that the shortest reac-
tion time and best yield were obtained in THF (84%, Table 1, entry
3) under sonic conditions. It is apparent that the ultrasound can
accelerate the reaction significantly. Thus, THF was chosen as the
solvent for this reaction under ultrasound irradiation.
Spectrum 100 spectrometer as KBr pellets with absorption in cm−1
.
Elemental analysis was performed on a Perkin Elmer PE 2400 ele-
mental analyzer. Baker’s yeast was obtained from local market.
Ultrasound irradiation was performed in a D-compact ultrasonic
cleaner with a frequency of 30 kHz and an output power of 250 W.
The reaction flask was kept at the maximum energy area in the
cleaner, and the surface of the reactants was placed slightly lower
than the level of water. The reaction temperature was controlled at
30 ◦C by addition or removal of water from ultrasonic bath.
3.2. Effect of different frequencies for ultrasound irradiation
2.2. Ultrasound-promoted general synthesis of
isoindolo[2,1-a]quinazoline
In order to verify the effect of irradiation frequency, two exper-
iments respectively at 30 and 40 kHz were performed. When the
frequency was 30 kHz, the yield of 4a was found to be 84% (Table 1,
entry 3). The yield of 4a (82%) (Table 1, entry 5) was found to be
almost the same at 40 kHz. With increase of irradiation frequency
from 30 to 40 kHz, the reaction yield was not affected to a consid-
erable amount. Synthesis of 4a at the frequency of 30 kHz at room
temperature was found very effective and other amines were tried
to synthesize a series of targeted compounds (4b–4l).
To the solution of isatoic anhydride 1 (1.22 mmol), 2-carboxy
benzaldehyde 2 (1.31 mmol) and amine 3 (1.40 mmol) in THF
(5 mL), active dry baker’s yeast (400 mg) was added. Then the reac-
tion mixture was sonicated at 30 kHz for stipulated time mentioned
in Table 2 at 30 ◦C. The progress of the reaction was monitored
by thin layer chromatography by using ethyl acetate:hexane (5:5)
as the eluent. After completion of the reaction the mass was fil-
tered through the bed of celite. From the filtrate, the solvent was
removed under reduced pressure and the crude products isolated
were crystallized from hot ethanol.
3.3. Synthesis of isoindolo[2,1-a]quinazoline derivatives 4 under
ultrasound irradiation
2.2.1. Spectral data of 6-(2-hydroxyethyl)-6,6a-
dihydroisoindolo[2,1-a]quinazoline-5,11-dione
(4c)
After optimization of the conditions, to delineate this
approach the methodology was evaluated by using different
aromatic/aliphatic amines. A series of substituted isoindolo[2,1-
a]quinazoline derivatives were synthesized using baker’s yeast in
THF at room temperature under sonic condition. Yeast was found
to efficiently catalyze the reaction between isatoic anhydride, 2-
carboxy benzaldehyde and a variety of amines affording moderate
to good yields of the desired products within 2–5 h (Table 2).
1H NMR (CDCl3, 400 MHz): 7.28–8.13 (m, 8H), 6.43 (s, 1H),
4.04–4.20 (m, 2H), 3.75–3.95 (m, 2H), 2.06 (br s, 1H, OH). 13C
NMR (CDCl3, 100 MHz): 164.99, 164.91, 138.21, 136.89, 133.70,
132.97, 132.59, 130.56, 128.97, 126.81, 125.23, 125.03, 120.31,
120.23, 71.76, 61.83, 45.40. IR (KBr): 3414 ( OH), 3095 ( CH), 1731
(
C O), 1635 ( C C), 1489 ( CH2), 1063 ( C
O) cm−1. ESI-MS:
Scheme 1. Synthetic pathway for the synthesis of isoindolo[2,1-a]quinazolines.

72
J.R. Avalani et al. / Journal of Molecular Catalysis B: Enzymatic 90 (2013) 70–75
Table 1
Solvent selection for the synthesis of 4a under ultrasound irradiation at room temperature.a
Entry
Solvent
Without ultrasoundb
Time (h)
With ultrasoundc
Time (h)
Yield (%)
Yield (%)
1
2
3
Methanol
Ethanol
24
24
24
40d
–
24
24
24
24
24
24
33
33
38
17d
–
41
40
36
31
n.d.
n.d.
4
4
2
40
35
84
THF
4d
5e
6
THFd
2d
2e
3.5
2
30d
82e
75
THFe
Acetonitrile
DCM
Dimethyl acetamide
DMF
Water
7
8
9
10
11
Trace
50
30
n.d.
n.d.
2.5
2.5
4
Phosphate buffer (pH 6.0)
4
n.d., not detected.
a
Reaction conditions: isatoic anhydride 1 (1.22 mmol), 2-carboxy benzaldehyde 2 (1.31 mmol), benzyl amine 3a (1.40 mmol) and solvent (5 mL), Baker’s yeast (400 mg).
Reaction temperature 30 ◦C.
b
Reaction without ultrasound. Reaction temperature 30 ◦C.
c
Reaction under ultrasonic irradiation at room temperature and the ultrasonic power 250 W and irradiation frequency 30 kHz.
d
Without baker’s yeast at 30 ◦C.
e
Reaction under ultrasonic irradiation at room temperature and the ultrasonic power 250 W and irradiation frequency 40 kHz.
Both aliphatic and aromatic amines 3 underwent smooth reac-
tion with isatoic anhydride 1 and 2-carboxy benzaldehyde 2 to
give high yields of products. The varied nature of the substituents
on the aromatic ring showed no obvious effect on this conver-
sion. Both benzylamine and p-methoxy benzylamine were suitable
substrates in this reaction, which resulted in the corresponding
products 84% and 83% respectively. Cyclic amines (entries 4 and 12)
also exhibited good yield. Aliphatic amines such as ethanolamine,
methylamine, and ethylamine also afforded moderate yields of
product (entries 3, 9 and 10). The structures of all the products
4 were established by IR, 1H NMR, 13C NMR, and MS spectroscopy.
In 1H NMR spectrum, singlet was observed around 6.3–7.05 ı
and in 13C NMR signal at 72.0–73.0 ı due to methine group
adjacent to nitrogen atom. The appearance of two signals in 13C
NMR at 163–165 ı ppm clearly indicate the presence of two non
equivalent C O carbons. The IR spectrum showed strong band
around 1650–1750 cm−1 due to C O stretching.
3.4. Reaction mechanism
The cell of baker’s yeast produces a variety of enzymes. It
is known to provide specific enzymes to specific reactions [60].
Among these enzymes, lipase available in baker’s yeast [61,62]
might be thought responsible for accelerating the reaction. It is well
known that lipase contains variety of different amino acid residues.
The amino acid residues like aspartic acid, histidine and serine
might be interacting with the substrate. NH proton of histidine
may be considered responsible [63] for enhancing electrophilic
character of carbonyl carbon of isatoic anhydride and 2-carboxy
benzaldehyde. Then decarboxylation occurs resulting in generation
Fig. 1. Plausible mechanism for the formation of isoindolo[2,1-a]quinazoline.

J.R. Avalani et al. / Journal of Molecular Catalysis B: Enzymatic 90 (2013) 70–75
73
Table 2
Synthesis of isoindolo[2,1-a]quinazolines using baker’s yeast under sonic condition.a
Entry
R
Product (4)
Time (HH:MM)
02:00
Yield (%)b
1
C6H5CH2-
4a
4b
84
80
2
C6H5-
04:00
3
C2H5O-
4c
4d
4e
4f
03:00
03:45
05:00
05:00
04:30
04:15
02:45
02:00
02:45
78
81
75
78
65
83
76
77
75
4
C5H9-
5
4-F-C6H4CH2-
4-Cl-C6H4CH2-
4-CH3-C6H4CH2-
4-OCH3-C6H4CH2-
CH3-
6
7
4g
4h
4i
8
9
10
11
CH3CH2-
4j
(NH)4CO3
4k

74
J.R. Avalani et al. / Journal of Molecular Catalysis B: Enzymatic 90 (2013) 70–75
Table 2 (Continued )
Entry
R
Product (4)
Time (HH:MM)
Yield (%)b
12
C3H5-
4l
03:15
81
a
Reaction conditions: isatoic anhydride 1 (1.22 mmol), 2-carboxy benzaldehyde 2 (1.31 mmol), amine 3 (1.40 mmol), THF (5 mL) and baker’s yeast 400 mg.
Isolated yield.
b
of 2-amino-N-substituted-benzamide (Fig. 1, a). The intermediate
Appendix A. Supplementary data
(a) reacts with 2-carboxy benzaldehyde generating imine interme-
diate, which is converted into the final product with loss of water
molecule. The mechanism is schematically presented in Fig. 1.
To ascertain the path way, the model reaction was stopped after
1 h. The collected sample was purified by column chromatography.
2-Amino-N-benzylbenzamide (a) was successfully isolated which
provided the support to the above proposed mechanism. This inter-
mediate was characterized by 1H NMR. 1H NMR (400 MHz, CDCl3):
ı 7.21–7.38 (m, 7H, Ar H), 6.63–6.72 (m, 2H, Ar H), 6.35 (s, 1H,
NH), 5.50 (s, 2H, NH2), 4.63 (d, J = 5.6 Hz, 2H, CH2).
Supplementary data associated with this article can be
found, in the online version, at http://dx.doi.org/10.1016/
j.molcatb.2013.01.024.
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