Novel bisbenzopyronopyran derivatives: photochemical synthesis and their in-vitro antimicrobial studies

Article abstract of DOI:10.1002/jhet.4171

The present research work describes the productive synthesis of novel bisbenzopyronopyran derivatives 4(a-h) and 5(a-h) via the photocyclization reactions of bischromones 3(a-h) under the inert conditions. The latter compounds have been realized efficiently through the O-alkylation reactions of the 3-hydroxychromone 2 with suitable dihalogenated aliphatic/aromatic/heteroaromatic reagents in the presence of dry acetone/anhydrous K₂CO₃/Bu₄N⁺I^? (PTC). The cyclization reaction of chalcone 1 under the Algar-Flynn-Oyamada reaction conditions (KOH/H₂O₂) could results in the formation of compound 2 in the good yield. The structural scaffolds of the newly prepared bischromones and resultant bisbenzopyronopyrans have been certified from the meticulous analysis of their various spectroscopic parameters such as UV-Vis, IR, ¹H/¹³C-NMR, and ESI-MS. It was found that o/m/p-xylene and pyridine-linked final symmetrical bistetracycles exhibited higher antimicrobial potencies as compared to alkyl chain-linked cyclized products. The bischromones 3(a-h) could be able to endow modest level of antimicrobial behavior.

Full text of DOI:10.1002/jhet.4171

Received: 19 August 2020
DOI: 10.1002/jhet.4171
Revised: 30 September 2020
Accepted: 12 October 2020
N O T E S
Novel bisbenzopyronopyran derivatives: photochemical
synthesis and their in-vitro antimicrobial studies
Shehneela Nisa | Mohamad Yusuf
Department of Chemistry, Punjabi
Abstract
University, Patiala, Punjab, India
The present research work describes the productive synthesis of novel
Correspondence
Mohamad Yusuf, Department of
bisbenzopyronopyran derivatives 4(a-h) and 5(a-h) via the photocyclization
reactions of bischromones 3(a-h) under the inert conditions. The latter com-
Chemistry, Punjabi University, Patiala-
1
47002, Punjab, India.
pounds have been realized efficiently through the O-alkylation reactions of the
Email: yusuf_sah04@yahoo.co.in
3
-hydroxychromone 2 with suitable dihalogenated aliphatic/aromatic/hetero-
+
−
aromatic reagents in the presence of dry acetone/anhydrous K CO /Bu N I
2
3
4
(PTC). The cyclization reaction of chalcone 1 under the Algar-Flynn-Oyamada
reaction conditions (KOH/H O ) could results in the formation of compound
2
2
2
in the good yield. The structural scaffolds of the newly prepared
bischromones and resultant bisbenzopyronopyrans have been certified from
the meticulous analysis of their various spectroscopic parameters such as UV-
1
13
Vis, IR, H/ C-NMR, and ESI-MS. It was found that o/m/p-xylene and
pyridine-linked final symmetrical bistetracycles exhibited higher antimicrobial
potencies as compared to alkyl chain-linked cyclized products. The
bischromones 3(a-h) could be able to endow modest level of antimicrobial
behavior.
1
| INTRODUCTION
compounds have been well understood geometrically and
these are the powerful tool for the efficient preparations
The study of synthetic photochemistry has provided a
competent and environment-friendly opportunity to
obtain together chemically and biologically significant
scaffolds. The photochemical pathways also contribute a
great prosperity in the preparations of many novel prod-
ucts which are not feasible through the normal thermal
of large variety of potent carbocyclic and heterocyclic
products. Different types of oxygenated heterocyclic prod-
ucts having conjugated enone moiety in their cyclic
scaffold play a fundamental role in the both synthetic and
natural systems because of their enormous and beneficial
[
5–8]
photochemical transformations.
[1]
routes. The prospect of employing photoreactions in
the generations of diverse classes of organic compounds
has been the scientifically sound area of research for the
Over the previous few decades, the studies on six-
membered oxygen heterocycles, such as pyrans and their
benzo derivatives, have become the subject of consider-
able interest in the field of organic syntheses owing to
[2]
chemists. The photoradiative processes are found to
occur without using any composite catalysts, specific
reagents, noxious solvents while the nonoccurrence of
multistep strategies have prevented the formation of
byproducts. These characteristics have made them more
[9–11]
their broad spectrum of pharmacological profiles.
These molecules form the structural motif of several syn-
thetic as well as naturally occurring biologically active
products including antibiotics, pheromones, alkaloids,
[
3,4]
[12–14]
attractive protocols in the hands of synthetic chemists.
The photochemical reactions of α,β-unsaturated carbonyl
and iridoids.
The pyran ring systems are extensively
dispersed in the plants and animal kingdom. These are
J Heterocyclic Chem. 2020;1–18.
wileyonlinelibrary.com/journal/jhet
© 2020 Wiley Periodicals LLC.
1

2
NISA AND YUSUF
utilized as the fragrant preservatives in cosmetics and
Literature observations suggest that molecules
encompassing coalesced chromen-4-one and pyran moie-
ties together in their frameworks are found to exhibit
noticeable bioactivities due to their unique physicochem-
[15,16]
food stuffs.
This family of compounds has been syn-
thetically developed due to their prevailing commercial
[17,18]
applications.
In addition, their derivatives can be
[
33]
used as an essential controller for photochemical activi-
ties and potassium cation channel. Benzopyran deriva-
tives are usually exploited as the potential biologically
ical properties.
Fused chromeno-pyran derivatives like
brosimone, cycloartocarpin, and ophioglonin are the
well-known products due to their tyrosinase inhibitory
[19]
[34]
active products.
and anti-HBV activity, respectively
(Figure 2).
Chromones (benzo-γ-pyrones or 4H-chromen-4-one)
are the privileged class of heterocyclic compounds con-
taining two chromophoric entities in their structures that
is, C=C and C=O which make them photochemically
The chromone derivatives have been found to exhibit
many interesting photoreactions like photodimerization,
phototautomerization, photo-oxidation, photorearrang
ements, photoreduction, and photoisomerization reac-
[20–22]
[35]
highly reactive molecules.
The structural heteroge-
tions.
Among these photoreactions, intramolecular
neity pertaining to the position, number, and nature of
various substituents associated to the central nucleus are
specifically consistent to their physical, chemical, and
hydrogen-abstractions have been successfully utilized for
the generations of some unique polyheterocyclic com-
pounds. The exhilarated interest in the syntheses and
photochemistry of variously substituted chromone sys-
tems has frequently enthralled the organic photochemists
in the past decades. This vast field remains an attractive
and challenging thrust area for the development of
oxygen containing tri- and tetracyclic compounds which
could be realized through the Norrish type-II
[23]
biological properties.
They are omnipresent in nature
particularly in plants realm and usually found as the
mother fragment in numerous flavonoids, that is, fla-
[24,25]
vones, flavonols, and isoflavones.
They are also
studied as pivotal intermediates in the generations of bio-
active heterocyclic systems. These substrates have
engrossed much attention in the field of synthetic chem-
[
36–39]
reactions.
The tethering of two chromone moieties
[26–30]
istry due to their wide range of bioactivities.
They
together by using different types of spacers (aliphatic/aro-
matic/heteroaromatic) lead to the generations of
bichromophoric molecules called as bischromones
3(a-h).
are also found to be associated with the array of physio-
logical processes. Furthermore, the chromone moiety is
found to be present in the various therapeutic drugs such
as baicalin (anti-inflammatory), nedocromil sodium
With aforesaid literature knowledge in mind and
by following our earlier results dealing with the
photo-transformations of 3-alkoxychromones/bischrom
(
anti-allergic), puerarin (alcohol abuse), iguratimod (anti-
[
31,32]
rheumatic), and cromolyn (anti-inflammatory)
[
40–44]
(Figure 1).
ones,
now we wish to report herein the detailed
FIGURE 1 Examples of chromone based therapeutic drugs

NISA AND YUSUF
3
FIGURE 2 Examples of bioactive
chromeno-pyrans
photochemical cyclization reactions of alkyl/aromatic/
heteroaromatic chain linked bischromones 3(a-h). The
foremost objective of this study was to establish a
straightforward photochemical protocol for the syntheses
of novel bisbenzopyronopyrans (bis-isochromeno-chro-
menones) 4(a-h)/5(a-h). The major interest in these
researches was also to unravel the impact of the interven-
ing units (aliphatic/aromatic/heteroaromatic) upon the
formations and antimicrobial portrait of the final
bistetracyclic products.
photoirradiations, the TLC started to exhibit the spot of
some polymeric stuff at the bottom along with two spots
of products. At this stage photoirradiations were switched
off, and then solvent was distilled off under the reduced
pressure to obtain the gummy mixtures of photolysates.
The latter were separated on the silica gel (100-200 mesh)
columns to provide two new products in each case
[3(a-h)]. These compounds were further crystallized
from CHCl to furnish the pure bisbenzopyronopyran
3
derivatives 4(a-h) and 5(a-h).
The structures of these products could be unequivo-
cally established through the contrasting of their UV-Vis/
1
13
2
| RESULTS AND DISCUSSION
IR/ESI-MS/ H-NMR/ C-NMR spectra with those of
starting compounds 3(a-h). The elemental analysis
results proved very helpful to establish the purity of the
newly prepared compounds. The synthetic route
espoused to attain the target products 4(a-h) and 5(a-h)
has been portrayed in Scheme 1 and the prospective
mechanism for their photochemical formations have
been revealed in Scheme 2.
Our approach to the target bisbenzopyronopyrans (bis-
isochromeno-chromenones) 4(a-h) and 5(a-h) has been
initially started (Scheme 1) from the synthesis of
3
-hydroxy-2-biphenyl-4H-chromen-4-one 2 which was
realized from the reaction of chalcone 1 under the Algar-
Flynn-Oyamada reaction conditions (KOH/H O ). The
2
2
subsequent O-alkylation reactions of the 2 with suitable
IR spectrum of compound 2 demonstrated a broad
band at 3174 cm− that could be easily allotted to the
stretching frequency of O-H group. Its UV-Vis spectrum
1
di-brominated reagents (1,4-dibromobutane, 1,5-dibromo
0
pentane, 1,6-dibromohexane, 1,8-dibromooctane, α,α -di
0
0
*
bromo-o-xylene, α,α -dibromo-m-xylene, α,α -dibromo-
exhibited two maxima at 340 and 238 nm due to n ! π
0
*
1
p-xylene, and 2,2 -bisbromomethyl-pyridine) in the pres-
and π ! π transition, respectively. In its H-NMR
ence of dry acetone/freshly dried K CO /tetra butyl
(500 MHz, CDCl ) spectrum, the prevalence of C -OH
2
3
3
3
ammonium iodide (phase transfer catalyst) escorted the
group was certified by the materialization of one proton
formations of bis-chromen-4-ones 3(a-h) in good yields.
broad singlet (exchangeable with D O) at δ 7.07. In the
2
+
−
The application of Bu N I in these reactions certainly
aromatic region, the four benzenoid ring protons (H-5,
4
0 0
improved the yields of bichromophoric products 3(a-h).
The chalcone 1 was easily prepared according to the pre-
6, 7, 8) and nine biphenyl ring hydrogens (H-2 to H-6
0
0
00
and H-2 to H-6 ) furnished their respective signals in
the region at δ 8.35-7.42 (see Section 5).
[45]
viously reported procedure in the literature.
Bischromen-4-ones 3(a-h) were extensively photo-
lyzed in dry MeOH with pyrex-filtered light by means of
Hg arc lamp (125 W) under the dry nitrogen atmosphere.
The durations of these photoreactions were carefully
optimized by using the TLC analyses of the photolytic
mixtures at the regular intervals of 30 min. After the pho-
toirradiations of about 4-5 h, most of the starting mate-
rials could be able to convert themselves into two types
of new photoproducts (TLC). Upon prolonged
UV-Vis spectra of 3(a-h) exhibited two peaks at
312-302 and 245-236 nm which may be produced by
*
*
n ! π and π ! π transition, respectively. IR spectra of
bischromones 3(a-h) were very supportive to analyze
their proposed structures. They did not concede any
absorption frequency in O-H group region, which defi-
nitely represented the involvement of this functionality
during the course of O-alkylation reactions. Here, intense
bands emerged at 1638-1630 cm− due to the conjugated
1

4
NISA AND YUSUF
SCHEME 1 Synthesis of bisbenzopyronopyrans 4(a-h) and 5(a-h)

NISA AND YUSUF
5
SCHEME 2 Proposed mechanism
for the formations of 4(a-h) and 5(a-h)
C=O group of the pyrone moiety while C=C stretching
realized at δ 143.92-142.86 could be easily relegated to
C-3 due to its presence in the double bond along with
coalition with an oxygen atom. The signals ensued in the
aliphatic region at δ 74.68-71.27 may be equipped to C3-
−
1
frequency aroused at 1614-1601 cm .
1
On the other hand in the 500 MHz H-NMR spectra
(
DMSO-d ) of 3(a-h), the D O exchangeable O-H proton
6
2
signal of 2 was found to be absent which again substanti-
ated the formation of bischromone via the ether linkages.
The C -OCH group protons in compounds 3(a-d) pro-
duced well defined triplets at δ 4.07-4.04 (Jvic = 6.7-6.0 Hz);
whereas, same hydrogens in 3(e-h) resonated in the form
of sharp singlets at δ 5.39-5.04. The downfield resonances
in case of the latter could be occurring due to the ben-
OCH group carbon atoms while rest of the carbon atoms
2
related to interior groups [(CH ) ] in 3(a-d) were found
2
n
to be located in the upfield region at δ 29.42-22.82. The
carbon atoms of internal aromatic rings (o/m/p-xylene/
pyridine) in 3(e-h) along with benzenoid (C-4a, C-5, C-6
3
2
0
0
C-7, C-8, C-8a) and biphenyl ring carbons (C-1 to C-6
0
0
00
and C-1 to C-6 ) fomented their signals in the aromatic
region at δ 140.73-117.32 (see Section 5).
zylic nature of these hydrogens (OCH ). The remaining
2
methylene group [(CH ) ] hydrogens in 3(a-d) engen-
IR spectra of symmetrical bisheterocycles 4(a-h) and
5(a-h) possessed strong absorptions in the carbonyl group
region at 1646-1632 cm− which clearly pronounced that
both side chromophoric units of bischromones 3(a-h)
have been involved in the formations of tetracyclic prod-
ucts. This observation also suggests the subsistence of
symmetry in their structural frameworks. UV-Vis spectra
of these products displayed two maxima at 354-322 and
2
n
dered their suitable quintet or multiplet in the region at δ
.77-1.33. The protons of intervening o/m/p-xylene/pyri-
1
1
dine rings as well as benzenoid/C -biphenyl rings gener-
2
ated the signals of suitable multiplicity in the region at δ
8
.18-7.35 (see Section 5).
13
In the
C-NMR (125 MHz, CDCl ) spectra of
3
bischromones 3(a-h), the C=O groups of pyrone moiety
were responsible to divulge the most downfield reso-
nances at δ 175.62-174.38. Other recognizable signals
*
291-232 nm which were easily assignable to n ! π and
*
π ! π transition, respectively.

6
NISA AND YUSUF
The structures of novel bisbenzopyronopyrans 4(a-h)
and 5(a-h) have been derived from their 500 MHz
located at δ 182.09-180.16 (C-7), 157.33-155.28 (C-11a),
156.35-155.04 (C-12a), and 143.92-143.13 (C-6a) while
rest of the aromatic ring carbon atoms were resonating in
the downfield region at δ 140.73-117.62 (see Section 5).
The pyran ring carbon atoms C-5 appeared easily at δ
80.73-74.16 while the upfield resonances situated at δ
32.88-20.54 in compounds 5(a-d) may be assigned to the
carbon atoms of the interior methylene groups [(CH2)n].
The ESI-MS spectral fragmentation data of newly syn-
thesized bischromones 3(a-h) and resulting bistetracyclic
photoproducts 4(a-h) and 5(a-h) displayed good obedi-
ence with their prospective structures (see Section 5).
1
H-NMR (CDCl /DMSO-d ) spectra. The contrast
3
6
1
of H-NMR spectra of 3(a-h) with those of 4(a-h) and
5
3
(a-h) showed that triplets present at δ 4.07-4.04 in
(a-d) and singlets in 3(e-h) at δ 5.39-5.04 were found to
be absent in case of the latter which clearly illustrated
that the internal chain C -OCH group has participated
3
2
in the photoproducts formations. The salient attribute in
1
the H-NMR spectra of 4(a-h) were the signals of
dihydrophenyl ring protons. Two significant resonances
present at δ 5.08-4.22 and δ 3.85-3.64 were easily dis-
pensed to H-5 and bridgehead proton H-4a, respectively.
The coupling value of J5,4a = 12.8-12.0 Hz manifested the
cis dispositions of H-4a and H-5, respectively. The H-1
and H-4 hydrogens appeared themselves as a broad sin-
glet or doublet at δ 6.38-6.14 and another doublet at δ
2.1 | Mechanistic considerations
The above described photochemical cyclizations of
bischromen-4-ones 3(a-h) may be occurring through the
Norrish Type-II-H-abstraction from the C -OCH group
6
.03-5.72, respectively. The appearance of four protons
multiplet at δ 2.95-2.74 could be straightforwardly elected
to H-2a. At the extreme right of the spectra, the protons
belonging to middle groups [(CH ) ] in products 4(a-d)
3
2
by the photoexcited C=O chromophore of the pyrone
moiety which could lead to the generations of
2
n
0
could be able to impart relevant signals in the region at δ
.79-1.42. The lowest field of the spectra included suitable
signals of benzenoid, internal o/m/p-xylene/pyridine and
1,4-diradicals 3 (a-h). The resulting diradicals may
ꢀ
1
undergo cyclizations through the clipping of -O-CH- radi-
0
cal with 6 -position of C -biphenyl ring to afford the
2
0
0
C -aryl ring protons at δ 8.28-7.30 (see Section 5). In their
tetracyclic intermediates 3 (a-h) in situ (Scheme 2). The
latter further follow (1,7)-H-sigmatropic reactions to pro-
vide the dihydrocyclized products 4(a-h) while the dehy-
drogenations of 3 (a-h) could results in the formations of
aromatized products 5(a-h).
3
13
1
25 MHz C-NMR (CDCl /DMSO-d ) spectra, the four
3 6
perceptible resonances positioned at δ 179.53-177.16,
56.76-154.22, 150.59-146.24, and 143.82-142.29 were eas-
ily appointed to C-7, C-11a, C-12a, and C-6a, respectively.
The dihydrophenyl ring carbon atoms were clearly situ-
ated at δ 139.38-133.31 (C-12b), 130.73-129.14 (C-3),
0
0
1
It is mentioned hereby that photolysis of these
bischromones 3(a-h) in dry THF also yielded the similar
cyclohydrogenated 4(a-h) and cyclodehydrogenated
5(a-h) products. Thus, hydrogen donating capability of
the solvent (protic and aprotic) did not have any signifi-
cant affect upon the outcome of these photochemical
reactions which describes the involvement of the intra-
molecular H-abstractions in these syntheses. When prod-
ucts 4(a-h) were separately photolyzed, they did not
yield any product similar to 5(a-h) rather some poly-
meric materials were always obtained. This observation
proves that 5(a-h) are not the dehydrogenated products
of 4(a-h), rather both types of photoproducts have been
1
(
24.63-124.06 (C-1), 123.56-121.15 (C-4), 78.03-73.16
C-5), 40.92-39.26 (C-4a), and 35.72-32.06 (C-2a). The
intervening group [(CH ) ] carbon atoms in compounds
2
n
4
(a-d) exhibited recognizable signals in aliphatic region
at δ 30.64-18.52. The carbon atoms of the remaining rings
rigged the predictable pattern of resonances in the aro-
matic region at δ 140.91-116.58 (see Section 5).
1
H-NMR spectra (500 MHz, CDCl /DMSO-d ) of
3
6
bistetracyclic products 5(a-h) were quite elementary that
contributed the majority of signals in aromatic region at
δ 8.27-7.36. The ring junction protons H-4a located in
photoproducts 4(a-h) were found to be absent altogether
0
0
realized independently from the same intermediates 3
(a-h). It is evident from these molecules that C -OCH
1
in these H-NMR spectra which fully supported the for-
3
2
mation of dehydrogenated products 5(a-h). The emer-
group hydrogens are benzylic in case of 3(e-h) which
gence of well-defined triplets at
δ
4.94-4.90
could lead to the formation of more stabilized benzyloxy
C -OCH- radical as compared to alkoxyl radicals which
3
ꢀ
(
Jvic = 12.8-12.0 Hz) in 5(a-d) while sharp singlets at δ
6
.00-5.91 in 5(e-h) could be easily imputed to H-5 proton
are involved in 3(a-d). This aspect was corroborated from
our experimental observation that alkyl chains linked
bischromones 3(a-d) produced the yields of both photo-
products in the range of 40-52% while chemical efficiency
of 60-74% was furnished by the aromatic (o/m/p-xylene)
and heteroaromatic units based compounds 3(e-h). Thus
of pyran ring. In compounds 5(a-d), the hydrogens of
interior groups [(CH ) ] afforded their respective signals
of the suitable multiplicities in the upfield region at δ
2
n
13
2
.04-1.51. C-NMR spectra (125 MHz, CDCl ) of these
3
compounds displayed four downfield signals which were

NISA AND YUSUF
7

8
NISA AND YUSUF

NISA AND YUSUF
9
chemical efficiency of final bisbenzopyronopyrans in
these reactions has been found to be dependent upon the
nature of intervening spacer units (alkyl and benzyl).
It is conspicuous from Table 1 that bischromones 3a
−1
and 3b showed prudent response (MIC-16 μg mL )
against the P. fluorescens, A. janus, and E. coli,
K. pneumoniae, S. pyogenes, respectively. Compound 3c
−1
was found to be exceedingly potent (MIC-8 μg mL )
against P. fluorescens; whereas, it exhibited the MIC value
of 16 μg mL− against B. subtilis and F. oxysporum. Com-
pound 3d furnished modest level of activity (MIC-
3
| ANTIMICROBIAL STUDIES
1
The in vitro antibacterial and antifungal evaluations of
newly prepared bischromones 3(a-h) and bisbenzopyro
nopyrans 4(a-h)/5(a-h) have been executed by adopting
−1
16 μg mL ) against bacterial species K. pneumoniae,
S. aureus and fungal pathogen P. glabrum. Compound 3e
was found to suppress the growth of P. aeruginosa and
E. coli, S. aureus, S. pyogenes, A. niger at the MIC value of
[46]
the serial tube dilution procedures.
Four Gram-
negative bacterium species (Pseudomonas aeruginosa,
Klebsiella pneumoniae, Escherichia coli, and Pseudomonas
fluorescens) and three Gram-positive pathogens (Bacillus
subtilis, Streptococcus pyogenes, and Staphylococcus
aureus) were used for the antibacterial activity. Five fun-
gal strains (Aspergillus janus, Aspergillus sclerotiorum,
Aspergillus niger, Penicillium glabrum, and Fusarium
oxysporum) were taken for carrying out the antifungal
analysis. The recorded minimal inhibitory concentrations
−1
8 and 16 μg mL , respectively. Bischromone 3f revealed
sensible level of actions against K. pneumoniae,
P. fluorescens, B. subtilis, F. oxysporum, and
A. sclerotiorum. The compound 3g demonstrated potent
−1
behavior (MIC-8 μg mL ) against A. sclerotiorum and it
−1
also furnished the modest potency (MIC-16 μg mL )
against E. coli, P. fluorescens, and A. janus. Bischromone
−1
3h was found to reveal the MIC value of 8 and 16 μg mL
−
1
(
MICs-μg mL ) values are defined as the least concen-
against S. aureus, P. glabrum, and K. pneumoniae,
trations of inspected antimicrobial agents, that is, bacteri-
cidal or fungicidal agents which completely arrested the
visible growth of tested pathogenic microbes. The stock-
pile solutions have been obtained by dissolving 10 mg of
tested samples and reference drugs (Amoxicillin and Flu-
F. oxysporum, respectively.
Table 2 construed that most of the bisbenzo
pyronopyrans 4(a-h) and 5 (a-h) evinced the modest to
−1
potent activities (MIC-16 and 8 μg mL ) against the
tested bacterial and fungal strains. Compound 4a showed
noteworthy response against B. subtilis at the MIC value
−1
conazole) in 10.0 mL of DMSO (1.0 mg mL ) subse-
quently these solutions were diluted in successions by
means of sterilized micropipette to provide the different
−1
of 8 μg mL ; whereas product 5a could be able to achieve
−1
substantial activity (MIC-8 μg mL ) against the
K. pneumoniae and F. oxysporum. The product 4b enacted
−1
concentrations of 128, 64, 32, 16, 8, and 4 μg mL . Fur-
ther, the bacterial and fungal suspensions prepared in
saline medium were injected to the serially diluted test
tubes. The chosen bacterial and fungal pathogens were
nourished in sterilized nutrient broth and malt extract
medium, respectively. The bacterial pathogens vaccinated
−1
significant result (MIC-8 μg mL ) against E. coli. Com-
pound 5b impeded the growth of bacterial pathogens
namely P. fluorescens and S. aureus at the MIC value of
−1
8 μg mL . Product 4c was found to be equipped with sen-
−1
sible performance (MIC-16 μg mL ) against E. coli,
P. aeruginosa, B. subtilis, S. pyogenes, P. glabrum, and
A. sclerotiorum. Bisbenzopyronopyrans 5c and 4d were
test tubes were carefully sustained in the incubator at
ꢀ
3
7 C for 24 h; whereas, fungal strains immunized tubes
ꢀ
−1
have been incubated at 28 C for 72 h and the reference
drugs were also reserved under the similar conditions for
correlating the results. After the appropriate incubation
periods, the immunized test tubes were examined visu-
ally for turbidity appearance. The tubes showing no
noticeable growth of tested organisms (bacteria and
fungi) and having the smallest amount of reference drug
were measured as the minimal inhibitory concentrations
found to be fabulously powerful (MIC-8 μg mL ) against
K. pneumoniae, F. oxysporum, A. sclerotiorum, and
S. pyogenes, respectively. Compound 5d manifested effi-
cient response against E. coli and A. niger at the MIC
−1
value of 8 μg mL , while product 4e conquered astonish-
ing actions against P. aeruginosa, B. subtilis, and
A. sclerotiorum at the similar MIC value. Bisheterocycle
−1
5e could access perceptible activity (MIC-8 μg mL )
against K. pneumoniae, P. fluorescens, S. aureus, and
P. glabrum. The compounds 4f and 5f exhibited noticeable
(MICs). The results achieved from these screenings have
been compiled in Tables 1 and 2. The attained MIC
values of bischromones 3(a-h) and symmetrical
bistetracycles 4(a-h) and 5(a-h) have been compared
among each other as well as with reference drugs (lower
MIC values depicts the higher activity of the tested
products).
−1
response (MIC-8 μg mL ) against S. pyogenes,
F. oxysporum and P. aeruginosa, P. fluorescens, A. niger,
respectively. Compound 4g displayed appreciable potency
−1
(MIC-8 μg mL ) against K. pneumoniae, B. subtilis, and
A. sclerotiorum. The product 5g revealed the momentous

10
NISA AND YUSUF
−
1
behavior (MIC-8 μg mL ) against E. coli, P. fluorescens,
S. aureus, and A. janus, while bisheterocycle 4h engen-
further purification. The melting point ranges of prepared
compounds were recorded in paraffin wax using open
glass capillaries and hence are uncorrected. XEVO G2-XS
QTOF spectrometer (I.I.T. Ropar, Punjab, India) was
used for scrutinizing the Positive-ion mode ESI Mass
Spectra; whereas, Infrared Spectra were run on a Perkin
Elmer FT-IR Spectrophotometer as neat samples
(Department of Chemistry, Punjabi University, Patiala,
India) with frequencies recorded in reciprocal centime-
−1
dered incredible outcome (MIC-8 μg mL ) against
P. aeruginosa, S. pyogenes, and F. oxysporum.
Bistetracyclic product 5h furnished potent behavior
against E. coli, K. pneumoniae, B. subtilis, A. niger, and
−1
A. sclerotiorum at the MIC value of 8 μg mL .
It is discernible from the above described antimicro-
bial results that o/m/p-xylene and pyridine linked
bisbenzopyronopyrans 4(e-h) and 5(e-h) seems to be
behaving as the promising antifungal and antibacterial
agents as compared to other bisheterocycles 4(a-d) and 5
−1
1
13
ters (cm ). Proton ( H) and carbon ( C) Nuclear Mag-
netic Resonance Spectra have been obtained in DMSO-d6
or CDCl3 solvent on a Bruker Advance 500 MHz
13
(
a-d) which are assembled around the four, five, six and
(125 MHz for C NMR) Neo Spectrometer (RSIC, Panjab
eight methylene groups.
University, Chandigarh, India) using SiMe as the refer-
4
ence material. The chemical shifts have been accounted
on the δ scale while the coupling constants (J) are rev-
1
4
| CONCLUSION
ealed in Hertz. The spin multiplicities in the H-NMR
spectra have been designated by using their standard
abbreviations such as m (multiplet), td (triplet of dou-
blet), dt (doublet of triplet), dd (doublet of doublet), q
(quartet), t (triplet), d (doublet), brs (broad singlet), and s
(singlet). The photochemical reactions have been oper-
ated in the pyrex reactor under the dry nitrogen atmo-
sphere. Thin-layer chromatography (TLC) plates
encrusted with silica gel G suspended in MeOH-CHCl3
(2:1) have been exploited at appropriate interval of times
for optimizing the durations of the photoreactions. For
TLC analyses, the mixture of hexane-EtOAc (9:1) has
been thoroughly employed as a mobile phase and spots
were carefully visualized by their exposure to the I2
fumes in the glass chamber. The separations as well as
purification of the photolytic mixtures have been carried
out by using the silica-gel (100-200 mesh) column chro-
matography where hexane/ethylacetate (1:3) has been
used as the eluents. Chalcone 1 was prepared and ana-
It may be concluded that the present investigations have
been able to develop the efficient photochemical method
for the syntheses of novel aliphatic/aromatic/hetero-
aromatic chains linked bisbenzopyronopyrans. These
products have been obtained by using the environmen-
tally benevolent protocol in which light has been used as
the reagent. Here, intramolecular H-abstraction reactions
have been exploited to yield novel symmetrical
bisbenzopyronopyrans. Furthermore, the nature of the
intervening spacer displayed profound influence on the
photochemical efficiency as well as antimicrobial perfor-
mances of the newly prepared bisbenzopyronopyrans.
The antimicrobial examinations revealed that resulting
photoproducts demonstrated significant efficacy against
the tested microorganisms than their intermediate ana-
logs. This aspect has vindicated our target toward the
photocyclization reactions of bischromones. It was found
that final bisheterocycles linked through aromatic and
heteroaromatic chains showed enhanced antimicrobial
activities as compared to other products which are built
around the varying length aliphatic chains. In general,
the bistetracyclic scaffolds seems to be the interesting
template for the recognition of potential antimicrobial
agents.
[45]
lyzed in the similar manner as reported in literature.
0
5.2 | Synthesis of 2-([1,1 -Biphenyl]-4-yl)-
3-hydroxy-4H-chromen-4-one 2
A mixture of chalcone 1 (2.0 g, 0.006 mol), powdered
KOH (1.0 g, 0.018 mol) and MeOH (20.0 mL) was vigor-
ꢀ
ously stirred for 30 min at 0 C, thereafter H O (1.5 g,
2
2
5
5
| EXPERIMENTAL
0.044 mol) was added drop-wise to this well stirred solu-
tion. As the addition of H O completed, the stirring of
2
2
.1 | Materials and method
the reaction mixture was further continued until initially
formed reddish-orange solution was transformed into an
intense yellow mass which depicted the accomplishment
of reaction. The ensued reaction mixture was poured
onto crushed iced and subsequently neutralized with
diluted hydrochloric acid to achieve a solid substance
which was filtered off and dried under suction. The crude
All the solvents and fine chemicals utilized to perform
the present research work have been purchased from the
various commercial suppliers such as Loba Chemie, S. D.
Fine, TCI, and Sigma-Aldrich chemical companies, and
these chemicals have been used as such without any

NISA AND YUSUF
11
0
0
product was purified by its crystallization in MeOH:
(4H, d, J = 8.4 Hz, H-2 , 6 ), 8.12 (2H, dd, J
= 2.4,
m,o
o
0
0
CHCl (1:1) to furnish the pure compound 2.
7.9 Hz, H-5), 7.91 (4H, d, J = 8.5 Hz, H-3 , 5 ), 7.85 (2H,
td, J = 2.0, 8.3 Hz, H-7), 7.80 (4H, d, J = 7.0 Hz, H-2 ,
00
6 ), 7.53 (2H, t, J = 7.4 Hz, H-8), 7.50 (4H, d, J = 7.3 Hz,
o o
H-3 , 5 ), 7.44 (4H, m, H-6, 4 ), 4.07 (4H, t, J = 6.1 Hz,
OCH ), 1.77 (4H, quintet, J = 6.3 Hz, OCH CH ); C-
NMR (125 MHz, CDCl ): δ 175.13 (C=O), 155.54 (C-8a),
3
0 0
155.27 (C-2), 143.48 (C-3), 140.73 (C-1 ), 133.52 (C-4 ),
3
o
ꢀ
00
Light yellow solid; yield 70%; m.p. 220-222 C; IR
m,o
o
−
1
(
1
(
KBr) υmax (cm ): 3174 (O-H), 3079 (aromatic C-H),
−
1
00
00
00
628 (C=O) and 1594 cm (C=C); UV-Vis (MeOH): λmax
vic
1
13
nm) 340, 238; H-NMR (500 MHz, CDCl ): δ 8.35 (2H,
3
2
vic
2
2
0
0
dt, Jm,o = 2.0, 7.0 Hz, H-2 , 6 ), 8.28 (1H, dd, J
= 2.1,
m,o
0
0
8
7
.0 Hz, H-5), 7.78 (2H, dt, Jm.o = 2.0, 8.0 Hz, H-3 , 5 ),
.73 (1H, td, Jm,o = 2.2, 7.0 Hz, H-8), 7.68 (2H, dt,
0
0
0
0
0
133.39 (C-1 ), 129.87 (C-7), 129.79 (C-2 , 6 ), 129.08 (C-3 ,
00
00
0
00
00
00
00
00
Jm,o = 2.5, 8.5, H-2 , 6 ), 7.63 (1H, d, J = 8.5 Hz, H-7),
5 ), 128.92 (C-2 , 6 ), 127.97 (C-3 , 5 ), 127.11 (C-4 ),
125.83 (C-5), 124.64 (C-4a), 124.24 (C-6), 118.04 (C-8),
72.31 (OCH ), 26.71 (OCH CH ); ESI-MS: m/z Calculated
for C H O : 682.24 [M] ; Found: 683.34 [M + 1]
46 34 6
(27%), 684.34 [M + 2] (12%), 706.32 [M + Na + 1]
o
00 00
= 2.0, 7.5, H-3 , 5 ), 7.42 (2H, m, H-6,
m,o
7
4
.49 (2H, td, J
0
0
13
), 7.07 (1H, brs, OH); C-NMR (100 MHz, DMSO-d6):
2
2
2
+
+
δ 172.84 (C=O), 154.52 (C-8a), 144.74 (C-2), 141.19 (C-3),
0
0
0
00
+
+
1
1
1
4
39.20 (C-1 ), 133.50 (C-4 ), 130.25 (C-1 ), 129.84 (C-7),
0
0
0
00
00
28.87 (C-2 , 6 ), 128.07 (C-3 , 5 ), 127.84 (C-2 , 6 ),
(8%); Anal. calc. for C H O : C, 80.92%; H, 5.02%;
46 34 6
Found: C, 81.24%; H, 5.04%.
0
0
00
00
26.82 (C-3 , 5 ), 126.66 (C-4 ), 126.54 (C-5), 124.73 (C-
a), 121.28 (C-6), 118.22 (C-8); ESI-MS: m/z Calculated
+
+
for C H O : 314.09 [M] ; Found: 315.14 [M + 1]
21
14 3
+
0
(
100%), 316.15 [M + 2]
(22%); Anal. calc. for
5.3.2 | 3,3 -(Pentane-1,5-diylbis[oxy])bis
(2-[[1,1 -biphenyl]-4-yl]-4H-chromen-
0
C H O : C, 80.24%; H, 4.49%; Found: C,
21
14 3
8
0.56%; H, 4.51%.
4-one) 3b
ꢀ
Off white solid; yield 63%; m.p. 138-140 C; IR (KBr)
−
1
5
.3 | General procedure for the synthesis
cm :3065 (aromatic C-H), 2936, 2872 (aliphatic C-H),
of bischromones 3(a-h)
1632 (C=O) and 1608 (C=C); UV-Vis (MeOH):
λmax(nm) 306, 237; H-NMR (500 MHz, DMSO-d ): δ 8.16
(4H, d, J = 7.6 Hz, H-2 , 6 ), 8.10 (2H, dd, J
0 0
7.3 Hz, H-5), 7.93 (4H, d, J = 8.2 Hz, H-3 , 5 ), 7.88 (4H,
o
1
6
0
0
To the well stirred suspension of chromone 2 (0.006 mol),
freshly ignited K CO (0.012 mol), Bu N I (0.002 mol),
and dry acetone (25.0 mL) was added the suitable di-
brominated reagents (1,4-dibromobutane, 1,5-dibromo
pentane, 1,6-dibromohexane, 1,8-dibromooctane, α,α -dib
= 2.2,
m,o
o
+
−
2
3
4
0
0
00
d, J = 7.8 Hz, H-2 , 6 ), 7.84 (2H, td, J
= 2.6, 8.0 Hz,
m,o
o
H-7), 7.55 (2H, t, J = 7.5 Hz, H-8), 7.50 (4H, d, J = 7.0 Hz,
o
o
0
00
00
00
H-3 , 5 ), 7.45 (4H, m, H-6, 4 ), 4.06 (4H, t, J = 6.7 Hz,
vic
0
0
romo-o-xylene, α,α -dibromo-m-xylene, α,α -dibromo-p-
xylene, and 2,2 -bisbromomethyl-pyridine, 0.003 mol)
OCH ), 1.73 (4H, quintet, J = 6.8 Hz, OCH CH ), 1.56
(2H, m, OCH CH CH ); C-NMR (125 MHz, CDCl ): δ
2 2 2 3
2
vic
2
2
0
13
slowly and slowly. The resulting mixtures were allowed
to stir under refluxing for 3-4 h. The consumption of
starting substrate was monitored by means of TLC (hex-
ane/ethyl acetate—9:1). After the completion, the reac-
tions mixtures were turned from orange-red to colorless
masses which were further decomposed into ice-HCl
with intense shaking to endow the solid substances.
The accessed crude products were crystallized by using
methanol/chloroform (1:1) which yielded the pure
bischromones 3(a-h).
174.46 (C=O), 155.96 (C-8a), 155.34 (C-2), 142.86 (C-3),
0
0
00
139.08 (C-1 ), 134.66 (C-4 ), 133.43 (C-1 ), 130.56 (C-7),
0
0
0
00
0
0
00
00
129.84 (C-2 , 6 ), 129.14 (C-3 , 5 ), 128.33 (C-2 , 6 ),
0
00
127.68 (C-3 , 5 ), 127.24 (C-4 ), 125.57 (C-5), 124.43 (C-
4a), 123.95 (C-6), 117.32 (C-8), 72.20 (OCH ), 29.42
2
(OCH CH ), 24.14 (OCH CH CH ); ESI-MS: m/z Calcu-
2
2
2
2
2
+
+
lated for C H O : 696.25 [M] ; Found: 697.36 [M + 1]
(32%), 698.36 [M + 2] (24%), 719.34 [M + Na] (10%);
Anal. calc. for C H O : C, 81.02%; H, 5.21%; Found: C,
4
7
36 6
+
+
47
36 6
81.34%; H, 5.18%.
0
0
5
(
.3.1 | 3,3 -(Butane-1,4-diylbis[oxy])bis
5.3.3 | 3,3 -(Hexane-1,6-diylbis[oxy])bis
0
0
2-[[1,1 -biphenyl]-4-yl]-4H-chromen-
(2-[[1,1 -biphenyl]-4-yl]-4H-chromen-
4-one) 3a
4-one) 3c
ꢀ
ꢀ
Off white solid; yield 59%; m.p. 210-212 C; IR (KBr)
Off white solid; yield 66%; m.p. 130-132 C; IR (KBr)
−
1
−1
cm :3062 (aromatic C-H), 2929, 2876 (aliphatic C-H),
630 (C=O) and 1611 (C=C); UV-Vis (MeOH):
λmax(nm) 308, 242; H-NMR (500 MHz, DMSO-d ): δ 8.18
cm :3068 (aromatic C-H), 2922, 2868 (aliphatic C-H),
1634 (C=O) and 1614 (C=C); UV-Vis (MeOH):
λmax(nm) 310, 240; H-NMR (500 MHz, DMSO-d ): δ 8.18
1
1
1
6
6

12
NISA AND YUSUF
1
(
2H, d, J = 8.5 Hz, H-5), 8.12 (4H, td, J
= 2.0, 8.5 Hz,
λmax(nm) 304, 236; H-NMR (500 MHz, DMSO-d ): δ 8.06
6
o
m,o
0
0
0
0
H-2 , 6 ), 7.90 (4H, d, J = 7.0 Hz, H-3 , 5 ), 7.82 (6H, m,
H-7, 2 , 6 ), 7.70 (2H, t, J = 8.4 Hz, H-8), 7.52 (2H, t,
J = 7.3 Hz, H-6), 7.48 (4H, m, H-3 , 5 ), 7.36 (2H, d,
J = 7.3 Hz, H-4 ), 4.05 (4H, t, J = 6.4 Hz, OCH ), 1.71
(2H, dd, J
= 2.5, 7.9 Hz, H-5), 7.93 (4H, dd, J = 2.2,
8.5 Hz, H-2 , 6 ), 7.82 (2H, td, J
7.71 (2H, d, J = 8.1 Hz, H-8), 7.63 (4H, dd, J
8.5 Hz, H-3 , 5 ), 7.54 (4H, dd, J
o
m,o
0
m,o
0
0
00
0
= 2.7, 7.1 Hz, H-7),
m,o
o
00
00
= 2.8,
= 2.6, 8.2 Hz, H-2 ,
o
o
m,o
0
00
0
0
00
o
vic
2
m,o
0
00
0
(4H, quintet, Jvic = 6.4 Hz, OCH CH ), 1.45 (4H, m,
6 ), 7.48 (2H, td, J
= 2.4, 7.9 Hz, H-6) 7.43 (8H, m, H-
2
2
m,o
13
00
00
000
000
000
OCH CH CH ); C-NMR (125 MHz, CDCl ): δ 174.94
(
3 , 4 , 5 , 3 , 6 ), 7.35 (2H, dd, J = 2.2, 8.2 Hz, H-4 ),
5.04 (4H, s, OCH2); C-NMR (125 MHz, CDCl ): δ
2
2
2
3
m,o
13
C=O), 155.52 (C-8a), 155.12 (C-2), 143.35 (C-3), 140.13
3
0
0
00
(C-1 ), 135.86 (C-4 ), 134.27 (C-1 ), 129.98 (C-7), 129.68
174.90 (C=O), 156.14 (C-8a), 155.23 (C-2), 143.04 (C-3),
0
0
0
0
00
00
00
000 000 0 0
(C-2 , 6 ), 129.02 (C-3 , 5 ), 128.47 (C-2 , 6 ), 128.30 (C-3 ,
139.99 (C-1 , 2 ), 139.85 (C-1 ), 135.72 (C-4 ), 133.37 (C-
00
00
00 0 0 0 0
1 ), 130.69 (C-7), 129.71 (C-2 , 6 ), 129.22 (C-3 , 5 ), 128.90
5
6
), 127.99 (C-4 ), 125.38 (C-5), 124.74 (C-4a), 124.36 (C-
), 118.53 (C-8), 72.08 (OCH ), 29.18 (OCH CH ), 26.32
0
0
00
00
00
000
000
(C-2 , 6 ), 128.66 (C-3 , 5 ), 127.95 (C-3 , 6 ), 127.04 (C-
2
2
2
0
0
000
000
(OCH CH CH ); ESI-MS: m/z Calculated for C H O :
4 ), 126.75 (C-4 , 5 ), 125.83 (C-5), 124.64 (C-4a), 124.22
2
2
2
48 38 6
+
+
7
+
5
10.27 [M] ; Found: 710.40 [M] (100%), 712.42 [M
2] (36%); Anal. calc. for C H O : C, 81.11%; H,
(C-6), 117.99 (C-8), 71.27 (OCH ); ESI-MS: m/z Calcu-
lated for C H O : 730.24 [M] ; Found: 731.34 [M + 1]
50 34 6
(100%), 732.35 [M + 2] (52%), 753.33 [M + Na] (42%),
54.33 [M + Na + 1] (21%); Anal. calc. for C H O : C,
50 34 6
2
+
+
+
48
38
6
+
+
.39%; Found: C, 80.78%; H, 5.41%.
+
7
8
2.18%; H, 4.69%; Found: C, 82.51%; H, 4.71%.
0
5
.3.4 | 3,3 -(Octane-1,8-diylbis[oxy])bis
0
(
4
2-[[1,1 -biphenyl]-4-yl]-4H-chromen-
0
-one) 3d
5.3.6 | 3,3 -((1,3-Phenylenebis
0
[
methylene])bis(oxy))bis(2-[[1,1 -biphenyl]-
ꢀ
Off white solid; yield 68%; m.p. 148-150 C; IR (KBr)
cm :3064 (aromatic C-H), 2930, 2879 (aliphatic C-H),
638 (C=O) and 1610 (C=C); UV-Vis (MeOH):
4-yl]-4H-chromen-4-one) 3f
−
1
ꢀ
1
Off white solid; yield 76%; m.p. 126-128 C; IR (KBr)
cm :3054, 3026 (aromatic C-H), 2950, 2845 (aliphatic C-
1
−1
λmax(nm) 302, 245; H-NMR (500 MHz, DMSO-d ): δ 8.17
6
(
2H, d, J = 8.5 Hz, H-5), 8.11 (4H, td, J
= 2.3, 8.7 Hz,
H), 1635 (C=O) and 1613 (C=C); UV-Vis (MeOH):
o
m,o
0
0
0
0
1
H-2 , 6 ), 7.91 (4H, d, J = 8.6 Hz, H-3 , 5 ), 7.83 (4H, td,
Jm,o = 2.6, 8.6 Hz, H-2 , 6 ), 7.78 (2H, td, J
7
H-3 , 4 , 5 ), 7.44 (2H, dd, J
(
Jvic = 6.8 Hz, OCH CH ), 1.42 (4H, m, OCH CH CH ),
1
λmax(nm) 307, 244; H-NMR (500 MHz, DMSO-d ): δ 8.12
o
6
00
00
= 2.0,
(2H, dd, J = 2.3, 7.9 Hz, H-5), 7.99 (4H, d, J = 8.3 Hz,
m,o
m,o
o
0 0
H-2 , 6 ), 7.84 (2H, td, J = 2.4, 7.2 Hz, H-7), 7.72 (2H, d,
m,o
.0 Hz, H-7), 7.73 (2H, d, J = 7.2 Hz, H-8), 7.50 (6H, m,
o
00
00
00
0 0 00 00
J = 7.9 Hz, H-8), 7.65 (8H, m, H-3 , 5 , 2 , 6 ), 7.58 (6H,
o
= 1.6, 7.0 Hz, H-6), 4.04
m,o
00 00 00 000
m, H-6, 3 , 5 ), 7.48 (3H, m, H-4 , 5 ), 7.42 (2H, d,
4H, t, Jvic = 6.0 Hz, OCH ), 1.68 (4H, quintet,
2
0
00
000
000
J = 7.3 Hz, H-4 , 6 ), 7.36 (1H, s, H-2 ), 5.28 (4H, s,
2
2
2
2
2
o
13
13
.33 (4H, m, OCH CH CH CH ); C-NMR (125 MHz,
OCH2); C-NMR (125 MHz, CDCl ): δ 174.38 (C=O),
2
2
2
2
3
000
CDCl ): δ 175.62 (C=O), 155.87 (C-8a), 155.53 (C-2),
156.30 (C-8a), 155.82 (C-2), 143.92 (C-3), 140.26 (C-1 ,
3
0
0
00
000 0 0 00
3 ), 139.67 (C-1 ), 134.45 (C-4 ), 133.17 (C-1 ), 130.65 (C-
1
1
2
1
2
43.16 (C-3), 140.38 (C-1 ), 133.91 (C-4 ), 133.06 (C-1 ),
0
0
0
0
0 0 0 0 000
7), 129.50 (C-2 , 6 ), 129.36 (C-3 , 5 ), 129.03 (C-5 ), 128.28
29.77 (C-7), 129.48 (C-2 , 6 ), 129.26 (C-3 , 5 ), 128.69 (C-
00
00
00
00
00
00 00 00 00 00 000
(C-2 , 6 ), 127.97 (C-3 , 5 ), 127.39 (C-4 ), 126.81 (C-4 ,
, 6 ), 127.82 (C-3 , 5 ), 127.40 (C-4 ), 125.59 (C-5),
0
00
000
24.88 (C-4a), 124.23 (C-6), 118.41 (C-8), 71.94 (OCH2),
9.02 (OCH CH ), 26.14 (OCH CH CH ), 22.82
6 ), 125.76 (C-5), 125.16 (C-2 ), 124.48 (C-4a), 124.06 (C-
6), 118.57 (C-8), 72.56 (OCH ); ESI-MS: m/z Calculated
2
2
2
2
2
2
+
+
(
OCH CH CH CH ); ESI-MS: m/z Calculated for
for C H O : 730.24 [M] ; Found: 730.36 [M] (100%),
50 34 6
731.36 [M + 1] (74%); Anal. calc. for C H O : C,
50 34 6
2
2
2
2
+
+
+
C H O : 738.30 [M] ; Found: 738.41 [M] (96%), 762.38
[
50
42
6
+
M + Na + 1] (25%); Anal. calc. for C H O : C,
82.18%; H, 4.69%; Found: C, 81.85%; H, 4.71%.
50
42 6
8
1.28%; H, 5.73%; Found: C, 81.60%; H, 5.75%.
0
5
.3.7 | 3,3 -((1,4-Phenylenebis
0
0
5
[
4
.3.5 | 3,3 -((1,2-Phenylenebis
[methylene])bis(oxy))bis(2-([1,1 -biphenyl]-
4-yl)-4H-chromen-4-one 3g
0
methylene])bis(oxy))bis(2-[[1,1 -biphenyl]-
-yl]-4H-chromen-4-one) 3e
ꢀ
Off white solid; yield 74%; m.p. 132-134 C; IR (KBr)
cm :3052, 3024 (aromatic C-H), 2948, 2883 (aliphatic C-
H), 1632 (C=O) and 1609 (C=C); UV-Vis (MeOH):
λmax(nm) 312, 238; H-NMR (500 MHz, DMSO-d ): δ 8.17
ꢀ
−1
Off white solid; yield 75%; m.p. 118-120 C; IR (KBr)
cm :3058, 3028 (aromatic C-H), 2950, 2880 (aliphatic C-
H), 1637 (C=O) and 1605 (C=C); UV-Vis (MeOH):
−
1
1
6

NISA AND YUSUF
13
(
8
6
2H, dd, J
= 2.6, 7.9 Hz, H-5), 8.06 (4H, td, J
= 2.4,
and consumption of their starting materials. The photoly-
sis of 3(a-h) after the appropriate intervals exhibited the
developments of two new photoproducts below the Rf
values (TLC) of their starting materials. After the comple-
tion of these reactions, the solvent was distilled off under
the reduced pressure and the photolysates thus acquired
were loaded on silica gel columns (100-200 mesh) stuffed
in pure hexane. The elution of columns with hexane-ethyl
acetate (1:3) solvent systems afforded two new products
which were further crystallizations from CH Cl to yield
m,o
0
m,o
0
0
0
00
.4 Hz, H-2 , 6 ), 7.84 (8H, td, J = 2.3, 7.1 Hz, H-3 , 5 , 2 ,
m,o
00
), 7.79 (2H, q, J = 7.0 Hz, H-7), 7.74 (2H, m, H-8), 7.53
o
00 00 00
(2H, td, Jm,o = 2.4, 7.1 Hz, H-5), 7.45 (6H, m, H-3 , 4 , 5 ),
000 000 000 000
.40 (4H, s, H-2 , 3 , 4 , 5 ), 5.39 (4H, s, OCH ); C-
2
13
7
NMR (125 MHz, CDCl ): δ 175.22 (C=O), 156.49 (C-8a),
3
000 000 0
1
1
1
55.69 (C-2), 142.88 (C-3), 140.55 (C-1 , 4 ), 139.32 (C-1 ),
35.20 (C-4 ), 134.31 (C-1 ), 129.94 (C-7), 129.88 (C-2 , 6 ),
0
0
00
0
0
0
00
00
00
00
29.19 (C-3 , 5 ), 128.86 (C-2 , 6 ), 128.51 (C-3 , 5 ), 127.56
00
000
000
000
000
(C-4 ), 127.42 (C-2 , 3 , 5 , 6 ), 125.63 (C-5), 124.13 (C-
2
2
4
a), 123.81 (C-6), 117.92 (C-8), 72.84 (OCH ); ESI-MS: m/z
the pure bistetracyclic compounds 4(a-h) and 5(a-h).
2
+
Calculated for C H O : 730.24 [M] ; Found: 731.33 [M
+
50 34 6
+
+
1] (56%), 753.30 [M + Na] (27%); Anal. calc. for
C H O : C, 82.18%; H, 4.69%; Found: C, 81.70%; H, 4.67%.
5.4.1 | (4aS,5S)-5-(2-((4aR,5R)-7-Oxo-
5
0 34 6
3
-phenyl-2,4a,5,7-tetrahydroisochromeno
[4,3-b]chromen-5-yl)ethyl)-3-phenyl-
0
5
[
.3.8 | 3,3 -((Pyridine-2,6-diylbis
4a,5-dihydroisochromeno[4,3-b]chromen-7
(2H)-one 4a
0
methylene])bis(oxy))bis(2-([1,1 -biphenyl]-
4
-yl)-4H-chromen-4-one) 3h
ꢀ
Light yellow solid; yield 15%; m.p. 182-184 C; IR (KBr)
ꢀ
−1
Light yellow solid; yield 77%; m.p. 179-180 C; IR (KBr)
cm :3062, 3037 (aromatic C-H), 2918, 2854 (aliphatic C-
H), 1636 (C=O) and 1601 (C=C); UV-Vis (MeOH):
λmax(nm) 303, 243; H-NMR (500 MHz, DMSO-d ): δ 8.13
cm :3058 (aromatic C-H), 2990, 2918, 2896, 2846 (ali-
phatic C-H), 1644 (C=O) and 1610 (C=C); UV-Vis
(MeOH): λmax(nm) 322, 241; H-NMR (500 MHz, DMSO-
d ): δ 8.25 (2H, d, J = 8.2 Hz, H-8), 7.87 (2H, d, J = 7.8 Hz,
−
1
1
1
6
6
o
o
0
00
0
(
3H, m, H-5, 4 ), 7.84 (4H, td, J
= 2.7, 8.5 Hz, H-2 ,
H-10), 7.57 (4H, m, H-9, 11), 7.45 (4H, d, J = 8.2 Hz, H-
o
m,o
0
0
0
0
0
0
0
0
6
8
8
7
), 7.76 (6H, m, H-7, 3 , 5 ), 7.69 (2H, d, J = 2.4 Hz, H-
2 , 6 ), 7.40 (6H, td, J = 0.9, 7.9 Hz, H-3 , 4 , 5 ), 6.14
m
p,o
000
000
), 7.67 (2H, brs, H-3 , 5 ), 7.52 (4H, td, J = 0.8,
.0 Hz, H-2 , 6 ), 7.42 (6H, t, J = 7.7 Hz, H-3 , 4 , 5 ),
.38 (2H, d, J = 7.2 Hz, H-6), 5.16 (4H, s, OCH ); C-
(2H, brs, H-1), 6.03 (2H, d, Jvic = 3.1 Hz, H-4), 4.30 (2H, d,
J5,4a = 12.7 Hz, H-5), 3.66 (2H, m, H-4a), 2.92 (4H, m, H-
2a), 1.79 (4H, m, CH2); C-NMR (125 MHz, DMSO-d ): δ
p,o
00
0
0
00
00
00
3
o
1
13
o
2
6
NMR (125 MHz, CDCl ): δ 174.90 (C=O), 156.19 (C-8a),
177.28 (C=O), 154.35 (C-11a), 147.23 (C-12a), 142.57 (C-
3
000
000
0
1
1
7
1
4
55.92 (C-2), 155.28 (C-2 , 6 ), 143.29 (C-3), 140.18 (C-
), 139.95 (C-4 ), 137.16 (C-1 ), 133.51 (C-4 ), 129.59 (C-
6a), 139.73 (C-7a), 139.30 (C-12b), 133.19 (C-1 ), 130.65 (C-
0
0
00
000
0
0
0
0
3), 129.44 (C-10), 128.08 (C-2 , 6 ), 127.89 (C-3 , 5 ), 126.73
0
00
0
0
0
00
00
0
), 129.22 (C-2 , 6 ), 128.90 (C-3 , 5 ), 127.95 (C-2 , 6 ),
(C-4 ), 126.39 (C-8), 124.23 (C-9), 124.06 (C-1), 121.89 (C-
0
0
00
27.14 (C-3 , 5 ), 126.99 (C-4 ), 125.84 (C-5), 124.76 (C-
4), 117.47 (C-11), 73.90 (C-5), 40.73 (C-4a), 32.06 (C-2a),
0
00
000
a), 124.21 (C-3 , 5 ), 121.64 (C-6), 118.06 (C-8), 74.68
28.79 (CH ); ESI-MS: m/z Calculated for C H O : 682.24
2
46 34 6
+
+
+
(
[
(
(
1
OCH ); ESI-MS: m/z Calculated for C H NO : 731.23
[M] ; Found: 682.14 [M] (100%), 683.14 [M + 1] (28%),
705.23 [M + Na] (53%); Anal. calc. for C H O : C,
2
49 33
6
+
+
+
+
M] ; Found: 732.34 [M + 1] (29%), 733.35 [M + 2]
15%), 754.33 [M + Na] (8%), 755.33 [M + Na + 1]
46
34 6
+
+
80.92%; H, 5.02%; Found: C, 81.24%; H, 5.04%.
5%); Anal. calc. for C H NO : C, 80.42%; H, 4.55%, N,
49
33
6
.91%; Found: C, 80.74%; H, 4.53%, N, 1.92%.
5
5
.4.2 | (S)-5-(2-((R)-7-Oxo-3-phenyl-
,7-dihydroisochromeno[4,3-b]chromen-
5
.4 | General protocol for the photolysis
5-yl)ethyl)-3-phenylisochromeno[4,3-b]
chromen-7(5H)-one 5a
of bischromones 3(a-h)
ꢀ
The bischromones 3(a-h) (0.001 mol) were dissolved in
dry MeOH (50.0 mL) by taking in pyrex vessel and the
dry nitrogen was bubbled through these solutions for
Brown solid; yield 25%; m.p. 244-246 C; IR (KBr)
−1
cm :3028 (aromatic C-H), 2918, 2846 (aliphatic C-H), 1639
(C=O) and 1599 (C=C); UV-Vis (MeOH): λmax(nm) 348,
285; H-NMR (500 MHz, DMSO-d ): δ 8.13 (2H, d,
Jo = 8.0 Hz, H-8), 7.92 (4H, td, Jm,o = 2.2, 8.4 Hz, H-1, 2),
1
3
4
0 min. These solutions were further photoirradiated for
-6 h by using light from 125-W mercury arc lamp by
6
maintaining the dry N atmosphere during these reac-
tions. The TLC plates (hexane/ethyl acetate: 9:1) were uti-
lized to scrutinize the progress of these photoreactions
7.81 (2H, t, J = 7.0 Hz, H-10), 7.74 (4H, m, H-4, 11), 7.63
2
o
0
0
(4H, d, J = 7.8 Hz, H-2 , 6 ), 7.56 (2H, td, J
= 1.6,
o
m,o
0
0
0
7.1 Hz, H-9), 7.46 (6H, q, J = 7.0 Hz, H-3 , 4 , 5 ), 4.93
o

14
NISA AND YUSUF
1
3
0
0
(
(
(
(
(
(
(
2H, t, Jvic = 6.2 Hz, H-5), 2.04 (4H, m, CH2); C-NMR
J
= 2.0, 7.2 Hz, H-9), 7.45 (6H, t, J = 7.5 Hz, H-3 , 4 ,
m,o
0
o
125 MHz, CDCl ): δ 180.78 (C=O), 157.23 (C-11a), 156.14
C-12a), 143.66 (C-6a), 139.92 (C-4a), 139.59 (C-7a), 133.91
5 ), 4.90 (2H, t, J = 6.6 Hz, H-5), 2.00 (4H, m, CH ), 1.58
3
vic
2
13
(2H, quintet, Jvic = 6.3 Hz, CH CH );
C-NMR
2
2
0
C-12b), 130.38 (C-1 ), 129.78 (C-3), 129.46 (C-10), 128.39
(125 MHz, CDCl ): δ 180.34 (C=O), 156.82 (C-11a), 155.12
(C-12a), 143.45 (C-6a), 140.58 (C-4a), 139.26 (C-7a),
3
0
0
C-4), 128.27 (C-1), 127.91 (C-2), 127.77 (C-2 , 6 ), 126.89
0
0
0
0
C-3 , 5 ), 125.50 (C-8), 124.99 (C-4 ), 124.59 (C-9), 117.62
132.74 (C-12b), 130.44 (C-1 ), 129.89 (C-3), 129.21 (C-10),
0 0
C-11), 74.45 (C-5), 30.15 (CH ); ESI-MS: m/z Calculated
128.56 (C-4), 128.11 (C-1), 127.53 (C-2), 126.94 (C-2 , 6 ),
2
+
+
0
0
0
for C H O : 678.20 [M] ; Found: 678.23 [M] (100%),
126.14 (C-3 , 5 ), 125.61 (C-8), 124.68 (C-4 ), 123.18 (C-9),
118.25 (C-11), 74.23 (C-5), 32.88 (CH ), 20.54 (CH CH );
ESI-MS: m/z Calculated for C H O : 692.22 [M] ;
Found: 692.16 [M] (100%), 715.32 [M + Na] (44%),
46 30 6
+
+
6
79.23 [M + 1] (63%), 680.23 [M + 2] (22%); Anal.
calc. for C H O : C, 81.40%; H, 4.46%; Found: C,
2
2
2
+
46
30
6
47 32 6
+
+
8
1.07%; H, 4.44%.
+
7
8
16.32 [M + Na + 1] (20%); Anal. calc. for C H O : C,
47 32 6
1.49%; H, 4.66%; Found: C, 81.81%; H, 4.68%.
5
3
.4.3 | (4aS,5S)-5-(3-((4aR,5R)-7-Oxo-
-phenyl-2,4a,5,7-tetrahydroisochromeno
[
4,3-b]chromen-5-yl)propyl)-3-phenyl-
a,5-dihydroisochromeno[4,3-b]chromen-7
2H)-one 4b
5.4.5 | (4aS,5S)-5-(4-((4aR,5R)-7-Oxo-
3-phenyl-2,4a,5,7-tetrahydroisochromeno
[4,3-b]chromen-5-yl)butyl)-3-phenyl-
4
(
4
a,5-dihydroisochromeno[4,3-b]chromen-7
ꢀ
Light yellow solid; yield 16%; m.p. 160-162 C; IR (KBr)
(2H)-one 4c
−
1
cm :3056 (aromatic C-H), 2995, 2916, 2882, 2829 (ali-
phatic C-H), 1640 (C=O) and 1608 (C=C); UV-Vis
MeOH): λmax(nm) 326, 236; H-NMR (500 MHz, DMSO-
ꢀ
Light yellow solid; yield 18%; m.p. 173-175 C; IR (KBr)
cm :3052 (aromatic C-H), 2983, 2912, 2895, 2841 (ali-
1
−1
(
d6): δ 8.24 (2H, d, Jo = 7.5 Hz, H-8), 7.88 (2H, d,
phatic C-H), 1642 (C=O) and 1616 (C=C); UV-Vis
1
J = 8.1 Hz, H-10), 7.58 (4H, m, H-9, 11), 7.44 (4H, d,
(MeOH): λmax(nm) 331, 244; H-NMR (500 MHz, CDCl ):
o
3
0
0
0
J = 7.8 Hz, H-2 , 6 ), 7.38 (6H, td, J = 0.5, 7.7 Hz, H-3 ,
4
δ 8.26 (2H, dd, Jm,o = 2.1, 7.4 Hz, H-8), 7.86 (2H, t,
o
0
p,o
0
, 5 ), 6.18 (2H, d, Jvic = 2.8 Hz, H-1), 6.00 (2H, d,
J = 7.3 Hz, H-10), 7.60 (4H, m, H-9, 11), 7.46 (4H, d,
o
0
0
0
0
0
Jvic = 2.8 Hz, H-4), 4.28 (2H, d, J5,4a = 12.4 Hz, H-5), 3.82
J = 8.0 Hz, H-2 , 6 ), 7.41 (6H, m, H-3 , 4 , 5 ), 6.16 (2H,
o
(
1
2H, m, H-4a), 2.95 (4H, m, H-2a), 1.76 (4H, m, CH ),
.48 (2H, quintet, Jvic = 6.4 Hz, CH CH ); C-NMR
2 2
brs, H-1), 5.98 (2H, d, Jvic = 2.6 Hz, H-4), 4.26 (2H, d,
J5,4a = 12.2 Hz, H-5), 3.69 (2H, m, H-4a), 2.89 (4H, m, H-
2a), 1.78 (4H, m, CH ), 1.46 (4H, quintet, J = 6.2 Hz,
2
13
(125 MHz, DMSO-d ): δ 177.16 (C=O), 155.14 (C-11a),
6
2
vic
13
1
1
2
(
5
46.48 (C-12a), 142.39 (C-6a), 139.82 (C-7a), 139.14 (C-
CH CH ); C-NMR (125 MHz, DMSO-d ): δ 178.36
2 2 6
0
2b), 132.26 (C-1 ), 130.73 (C-3), 129.86 (C-10), 127.64 (C-
(C=O), 154.22 (C-11a), 146.71 (C-12a), 143.60 (C-6a),
0
0
0
0
0
0
, 6 ), 127.36 (C-3 , 5 ), 126.43 (C-4 ), 126.19 (C-8), 125.75
139.65 (C-7a), 139.07 (C-12b), 133.92 (C-1 ), 130.40 (C-3),
0
0
0
0
C-9), 124.63 (C-1), 123.40 (C-4), 118.16 (C-11), 73.16 (C-
129.26 (C-10), 128.11 (C-2 , 6 ), 127.25 (C-3 , 5 ), 126.35
0
), 39.28 (C-4a), 32.54 (C-2a), 30.64 (CH ), 18.52
(C-4 ), 126.24 (C-8), 125.82 (C-9), 124.54 (C-1), 122.38 (C-
2
(
[
6
8
CH CH ); ESI-MS: m/z Calculated for C H O : 696.25
4), 118.67 (C-11), 73.68 (C-5), 39.36 (C-4a), 33.82 (C-2a),
2
+
2
47 36 6
+
+
M] ; Found: 696.38 [M] (100%), 697.38 [M + 1] (38%),
30.48 (CH ), 26.20 (CH CH ); ESI-MS: m/z Calculated for
2
2
2
+
+
+
98.38 [M + 2] (14%); Anal. calc. for C H O : C,
C H O : 710.27 [M] ; Found: 710.38 [M] (100%),
48 38 6
733.32 [M + Na] (56%); Anal. calc. for C H O : C,
48 38 6
47
36
6
+
1.02%; H, 5.21%; Found: C, 81.34%; H, 5.18%.
81.11%; H, 5.39%; Found: C, 81.43%; H, 5.41%.
5
5
5
.4.4 | (S)-5-(3-((R)-7-Oxo-3-phenyl-
,7-dihydroisochromeno[4,3-b]chromen-
-yl)propyl)-3-phenylisochromeno[4,3-b]
5.4.6 | (S)-5-(4-((R)-7-Oxo-3-phenyl-
5,7-dihydroisochromeno[4,3-b]chromen-
5-yl)butyl)-3-phenylisochromeno[4,3-b]
chromen-7(5H)-one 4c
chromen-7(5H)-one 5b
ꢀ
Brown solid; yield 28%; m.p. 216-218 C; IR (KBr)
−1
ꢀ
cm :3041 (aromatic C-H), 2920, 2845 (aliphatic C-H),
633 (C=O) and 1603 (C=C); UV-Vis (MeOH):
Brown solid; yield 29%; m.p. 238-240 C; IR (KBr)
−1
1
cm :3026 (aromatic C-H), 2912, 2839 (aliphatic C-H),
1
λmax(nm) 352, 280; H-NMR (500 MHz, CDCl ): δ 8.12
1641 (C=O) and 1607 (C=C); UV-Vis (MeOH):
3
1
(2H, dd, Jm,o = 2.6, 8.2 Hz, H-8), 7.94 (4H, d, J = 7.7 Hz,
λmax(nm) 349, 288; H-NMR (500 MHz, DMSO-d ): δ 8.15
o
6
H-1, 2), 7.83 (2H, d, J = 7.8 Hz, H-10), 7.75 (4H, m, H-4,
(2H, t, J = 7.4 Hz, H-8), 7.91 (4H, dd, J = 0.7, 8.1 Hz,
H-1, 2), 7.81 (2H, td, Jm,o = 2.2, 7.3 Hz, H-10), 7.76
o
o
p,o
0
0
1
1), 7.62 (4H, d, J = 7.5 Hz, H-2 , 6 ), 7.55 (2H, dd,
o

NISA AND YUSUF
15
0
0
0
0
(
(
4
4H, m, H-4, 11), 7.64 (4H, t, J = 7.6 Hz, H-2 , 6 ), 7.58
d, J = 7.1 Hz, H-2 , 6 ), 7.54 (2H, dd, J = 2.3, 7.0 Hz,
m,o
o
o
0
0
0
0
0
0
2H, dd, Jm,o = 1.8, 7.2 Hz, H-9), 7.47 (6H, m, H-3 , 4 , 5 ),
.92 (2H, t, Jvic = 6.3 Hz, H-5), 2.03 (4H, m, CH ), 1.56
4H, quintet, Jvic = 6.9 Hz, CH CH ); C-NMR (125 MHz,
H-9), 7.44 (6H, t, J = 7.4 Hz, H-3 , 4 , 5 ), 4.94 (2H, t,
o
Jvic = 6.8 Hz, H-5), 2.01 (4H, m, CH ), 1.57 (4H, quintet,
Jvic = 6.4 Hz, CH CH ), 1.51 (4H, m, CH CH CH ); C-
2
2
13
13
(
2
2
2
2
2
2
2
CDCl ): δ 181.26 (C=O), 156.94 (C-11a), 155.48 (C-12a),
NMR (125 MHz, CDCl ): δ 180.49 (C=O), 157.31 (C-11a),
3
3
1
1
1
43.13 (C-6a), 139.73 (C-4a), 139.12 (C-7a), 133.19 (C-12b),
156.04 (C-12a), 143.24 (C-6a), 139.84 (C-4a), 138.96 (C-7a),
0
0
29.76 (C-1 ), 129.64 (C-3), 129.34 (C-10), 129.02 (C-4),
133.67 (C-12b), 129.91 (C-1 ), 129.43 (C-3), 129.05 (C-10),
0
0
0
0
0 0
28.46 (C-1, 2), 127.85 (C-2 , 6 ), 126.51 (C-3 , 5 ), 125.83
128.96 (C-4), 128.49 (C-1), 127.64 (C-2), 127.43 (C-2 , 6 ),
0
0
0
0
(C-8), 124.48 (C-4 ), 123.86 (C-9), 117.91 (C-11), 74.16 (C-
126.68 (C-3 , 5 ), 125.22 (C-8), 124.74 (C-4 ), 124.19 (C-9),
5
), 32.62 (CH ), 28.34 (CH CH ); ESI-MS: m/z Calculated
118.34 (C-11), 74.64 (C-5), 32.50 (CH ), 28.18 (CH CH ),
2
2
+
2
2
2
2
+
for C H O : 706.24 [M] ; Found: 706.40 [M] (100%),
24.74 (CH CH CH ); ESI-MS: m/z Calculated for
2 2 2
48
34
6
+
+
+
7
8
08.40 [M + 2] (79%); Anal. calc. for C H O : C,
1.57%; H, 4.85%; Found: C, 81.24%; H, 4.87%.
C H O : 734.27 [M] ; Found: 735.34 [M + 1] (100%),
50 38 6
48
34
6
+
757.36 [M + Na] (33%); Anal. calc. for C H O : C,
50 38 6
81.72%; H, 5.21%; Found: C, 82.04%; H, 5.23%.
5
3
.4.7 | (4aS,5S)-5-(6-((4aR,5R)-7-Oxo-
-phenyl-2,4a,5,7-tetrahydroisochromeno
5.4.9 | (4aS,5R)-5-(2-((4aR,5S)-7-Oxo-
[
4
(
4,3-b]chromen-5-yl)hexyl)-3-phenyl-
a,5-dihydroisochromeno[4,3-b]chromen-7
2H)-one 4d
3-phenyl-2,4a,5,7-tetrahydroisochromeno
[4,3-b]chromen-5-yl)phenyl)-3-phenyl-
4a,5-dihydroisochromeno[4,3-b]chromen-7
(
2H)-one 4e
ꢀ
Light yellow solid; yield 20%; m.p. 169-171 C; IR (KBr)
−1
ꢀ
Light yellow solid; yield 25%; m.p. 194-196 C; IR (KBr)
cm :3063, 3033 (aromatic C-H), 2956, 2918, 2849 (ali-
phatic C-H), 1635 (C=O) and 1614 (C=C); UV-Vis
(MeOH): λmax(nm) 328, 246; H-NMR (500 MHz, DMSO-
d6): δ 8.26 (2H, d, Jo = 8.1 Hz, H-8), 7.89 (2H, dd,
cm :3060 (aromatic C-H), 2986, 2920, 2898, 2830 (aliphatic
C-H), 1638 (C=O) and 1611 (C=C); UV-Vis (MeOH):
λmax(nm) 329, 232; H-NMR (500 MHz, DMSO-d ): δ 8.22
−1
1
6
1
(
1
7
2H, td, Jm,o = 2.5, 7.6 Hz, H-8), 7.85 (2H, d, J = 7.4 Hz, H-
o
0
0
0), 7.59 (4H, m, H-9, 11), 7.47 (4H, t, J = 8.3 Hz, H-2 , 6 ),
o
0
0
0
.37 (6H, dd, Jm,o = 2.0, 8.1 Hz, H-3 , 4 , 5 ), 6.20 (2H, brs, H-
), 6.02 (2H, d, Jvic = 3.2 Hz, H-4), 4.22 (2H, d,
J5,4a = 12.0 Hz, H-5), 3.75 (2H, m, H-4a), 2.93 (4H, m, H-2a),
.75 (4H, m, CH ), 1.49 (4H, quintet, J = 6.0 Hz, CH CH ),
Jm,o = 2.0, 7.8 Hz, H-10), 7.72 (2H, d, J = 8.4 Hz, H-11),
7.56 (2H, td, J
o
1
= 2.3, 8.3 Hz, H-9), 7.47 (4H, d,
m,o
0
0
J = 8.1 Hz, H-2 , 6 ), 7.40 (6H, td, J
= 2.0, 7.9 Hz, H-
o
m,o
000
0
0
0
000
1
1
3 , 4 , 5 ), 7.35 (2H, d, J = 7.3 Hz, H-3 , 6 ), 7.33 (2H, t,
000 000
J = 7.2 Hz, H-4 , 5 ), 6.38 (2H, d, J = 2.6 Hz, H-1),
o vic
2
vic
2
2
o
13
.42 (4H, m, CH CH CH ); C-NMR (125 MHz, DMSO-d6):
2
2
2
δ 178.45 (C=O), 155.86 (C-11a), 147.84 (C-12a), 142.29 (C-6a),
5.88 (2H, d, Jvic = 2.1 Hz, H-4), 4.99 (2H, d,
0
1
39.76 (C-7a), 139.28 (C-12b), 132.54 (C-1 ), 129.88 (C-3),
J5,4a = 12.6 Hz, H-5), 3.64 (2H, m, H-4a), 2.90 (4H, m, H-
0
0
0
0
0
13
1
1
(
2
29.75 (C-10), 128.46 (C-2 , 6 ), 127.78 (C-3 , 5 ), 126.86 (C-4 ),
26.36 (C-8), 124.79 (C-9), 124.22 (C-1), 121.15 (C-4), 117.86
C-11), 73.32 (C-5), 40.58 (C-4a), 32.95 (C-2a), 30.26 (CH2),
6.04 (CH CH ), 22.72 (CH CH CH ); ESI-MS: m/z Calcu-
2a); C-NMR (125 MHz, DMSO-d ): δ 178.07 (C=O),
6
155.92 (C-11a), 146.67 (C-12a), 143.33 (C-6a), 139.68 (C-
0
0
0
0
0
0
0
1 , 2 ), 139.59 (C-7a), 133.31 (C-12b), 130.19 (C-1 ),
000 000
129.14 (C-3), 128.39 (C-10), 128.23 (C-3 , 6 ), 127.02 (C-
2
2
2
2
+
2
+
000
000
0
0
0
0
0
lated for C H O : 738.30 [M] ; Found: 739.18 [M + 1]
4 , 5 ), 126.43 (C-2 , 6 ), 126.13 (C-3 , 4 , 5 ), 126.08 (C-
8), 124.53 (C-9), 124.28 (C-1), 123.16 (C-4), 119.47 (C-11),
74.54 (C-5), 40.92 (C-4a), 34.28 (C-2a); ESI-MS: m/z Cal-
5
0 42 6
+
(100%), 762.12 [M + Na + 1] (25%); Anal. calc. for
C H O : C, 81.28%; H, 5.73%; Found: C, 81.60%; H, 5.75%.
50 42 6
+
+
culated for C H O : 730.24 [M] ; Found: 730.06 [M]
100%), 731.06 [M + 1] (58%), 732.06 [M + 2] (22%),
754.38 [M + Na + 1] (20%); Anal. calc. for C H O : C,
50 34 6
50
34 6
+
+
(
+
5.4.8 | (S)-5-(6-((R)-7-Oxo-3-phenyl-
5,7-dihydroisochromeno[4,3-b]chromen-
5-yl)hexyl)-3-phenylisochromeno[4,3-b]
82.18%; H, 4.69%; Found: C, 82.50%; H, 4.71%.
chromen-7(5H)-one 5d
5
.4.10 | (S)-5-(2-(((R)-7-Oxo-3-phenyl-
ꢀ
Brown solid; yield 32%; m.p. 220-222 C; IR (KBr)
5,7-dihydroisochromeno[4,3-b]chromen-
5-yl)methyl)benzyl)-3-phenylisochromeno
[4,3-b]chromen-7(5H)-one 5e
−1
cm :3023 (aromatic C-H), 2926, 2850 (aliphatic C-H),
634 (C=O) and 1600 (C=C); UV-Vis (MeOH):
1
1
λmax(nm) 352, 286; H-NMR (500 MHz, DMSO-d ): δ 8.16
6
ꢀ
(2H, td, Jm,o = 2,3, 7.9 Hz, H-8), 7.93 (4H, m, H-1, 2), 7.88
Light brown solid; yield 35%; m.p. 232-234 C; IR (KBr)
cm :3058, 3028 (aromatic C-H), 2946, 2880 (aliphatic
−1
(
2H, t, J = 7.3 Hz, H-10), 7.75 (4H, m, H-4, 11), 7.66 (4H,
o

16
NISA AND YUSUF
C-H), 1637 (C=O) and 1602 (C=C); UV-Vis (MeOH):
5.4.12 | (S)-5-(3-(((R)-7-Oxo-3-phenyl-
1
λmax(nm) 350, 289; H-NMR (500 MHz, DMSO-d ): δ
5,7-dihydroisochromeno[4,3-b]chromen-
5-yl)methyl)benzyl)-3-phenylisochromeno
[4,3-b]chromen-7(5H)-one 5f
6
8
8
.18 (2H, d, J = 8.5 Hz, H-8), 7.93 (4H, td, J
= 2.2,
m,o
o
.4 Hz, H-1, 2), 7.81 (2H, t, J = 7.0 Hz, H-10), 7.77
o
0
(
6
4H, m, H-4, 11), 7.64 (4H, td, J
= 2.3, 8.0 Hz, H-2 ,
m,o
0
ꢀ
), 7.56 (2H, td, J
= 1.3, 7.0 Hz, H-9), 7.45 (6H, m,
Light brown solid; yield 37%; m.p. 250-252 C; IR (KBr)
m,o
0
0
0
000
000
−1
H-3 , 4 , 5 ), 7.37 (2H, dd, J
= 2.4, 8.0 Hz, H-3 , 6 ),
cm :3056, 3022 (aromatic C-H), 2953, 2876 (aliphatic C-
m,o
0
00
000
7
.33 (2H, t, J = 7.2 Hz, H-4 , 5 ), 5.92 (2H, s, H-5);
H), 1645 (C=O) and 1606 (C=C); UV-Vis (MeOH):
o
1
3
1
C-NMR (125 MHz, CDCl ): δ 181.58 (C=O), 155.35
λmax(nm) 354, 284; H-NMR (500 MHz, CDCl ): δ 8.16
3
3
(
1
C-11a), 155.07 (C-12a), 143.91 (C-6a), 140.73 (C-4a),
(2H, dd, Jm,o = 2.2, 8.0 Hz, H-8), 7.95 (4H, m, H-1, 2),
000
000
39.41 (C-7a), 137.74 (C-1 , 2 ), 133.68 (C-12b), 133.55
7.84 (2H, d, J = 7.2 Hz, H-10), 7.76 (4H, m, H-4, 11),
o
0
000
000
0 0
7.69 (4H, d, J = 8.2 Hz, H-2 , 6 ), 7.54 (2H, dd, J = 2.4,
o m,o
(C-3, 1 ), 129.52 (C-10), 129.30 (C-4), 128.25 (C-3 , 6 ),
0
0
00
000
0
0
0 0 0 000
7.3 Hz, H-9), 7.47 (7H, m, H-3 , 4 , 5 , 5 ), 7.38 (2H, d,
1
1
9
27.90 (C-4 , 5 ), 127.17 (C-1, 2), 126.01 (C-2 , 6 ),
0
0
000 000 000
J = 7.6 Hz, H-4 , 6 ), 7.32 (1H, s, H-2 ), 5.91 (2H, s, H-
o
25.52 (C-3 , 5 ), 124.96 (C-8), 124.45 (C-4 ), 121.65 (C-
13
), 118.10 (C-11), 76.48 (C-5); ESI-MS: m/z Calculated
5); C-NMR (125 MHz, CDCl ): δ 180.16 (C=O), 156.20
3
+
+
for C H O : 726.20 [M] ; Found: 727.42 [M + 1]
(
7
C H O : C, 82.63%; H, 4.16%; Found: C,
8
(C-11a), 155.33 (C-12a), 143.72 (C-6a), 139.98 (C-4a),
5
0
30 6
+
+
000
000
100%), 728.42 [M + 2] (52%), 749.18 [M + Na] (30%),
139.01 (C-7a), 138.67 (C-1 , 3 ), 132.86 (C-12b), 130.18
+
0
50.18 [M + Na + 1]
(19%); Anal. calc. for
(C-1 ), 129.66 (C-3), 129.34 (C-10), 129.23 (C-4), 129.16
0
00
0
0
(C-5 ), 128.46 (C-1), 127.13 (C-2), 126.84 (C-2 , 6 ), 126.29
50
30 6
0
0
000
000
000
2.96%; H, 4.18%.
(C-3 , 5 ), 126.03 (C-4 , 6 ), 125.33 (C-8), 125.21 (C-2 ),
0
1
24.89 (C-4 ), 123.38 (C-9), 119.41 (C-11), 76.52 (C-5);
ESI-MS: m/z Calculated for C H O : 726.20 [M] ;
Found: 726.04 [M] (100%), 727.04 [M + 1] (86%); Anal.
calc. for C H O : C, 82.63%; H, 4.16%; Found: C,
+
50
30 6
+
+
5
3
.4.11 | (4aS,5R)-5-(3-((4aR,5S)-7-Oxo-
-phenyl-2,4a,5,7-tetrahydroisochromeno
50
30 6
82.96%; H, 4.14%.
[
4
(
4,3-b]chromen-5-yl)phenyl)-3-phenyl-
a,5-dihydroisochromeno[4,3-b]chromen-7
2H)-one 4f
5
.4.13 | (4aS,5R)-5-(4-((4aR,5S)-7-Oxo-
ꢀ
Light yellow solid; yield 26%; m.p. 188-190 C; IR (KBr)
3-phenyl-2,4a,5,7-tetrahydroisochromeno
[4,3-b]chromen-5-yl)phenyl)-3-phenyl-
4a,5-dihydroisochromeno[4,3-b]chromen-7
(2H)-one 4g
−
1
cm :3075, 3028 (aromatic C-H), 2940, 2848 (aliphatic
C-H), 1646 (C=O) and 1615 (C=C); UV-Vis (MeOH):
λmax(nm) 325, 240; H-NMR (500 MHz, DMSO-d ): δ
.21 (2H, d, J = 7.9 Hz, H-8), 7.90 (2H, td, J
.6 Hz, H-10), 7.73 (2H, t, Jo = 8.2 Hz, H-11), 7.55
= 2.4, 7.0 Hz, H-9), 7.49 (5H, m, H-2 , 6 ,
), 7.42 (6H, dd, Jm,o = 2.4, 8.1 Hz, H-3 , 4 , 5 ), 7.34
2H, d, J = 7.0 Hz, H-4 , 6 ), 7.30 (1H, s, H-2 ), 6.32
2H, brs, H-1), 5.79 (2H, d, Jvic = 3.3 Hz, H-4), 4.98
2H, d, J5,4a = 12.8 Hz, H-5), 3.78 (2H, m, H-4a), 2.79
C-NMR (125 MHz, DMSO-d ): δ
78.56 (C=O), 156.76 (C-11a), 146.24 (C-12a), 142.43
C-6a), 139.68 (C-7a), 138.78 (C-1 , 3 ), 133.56 (C-
2b), 133.03 (C-1 ), 130.64 (C-3), 129.51 (C-5 ), 128.98
C-10), 127.95 (C-2 , 6 ), 127.66 (C-3 , 5 ), 126.72 (C-4 ),
26.39 (C-8), 126.11 (C-4 , 6 ), 125.19 (C-9), 125.02
1
6
8
7
= 2.2,
m,o
o
ꢀ
Light yellow solid; yield 28%; m.p. 164-166 C; IR (KBr)
cm :3068, 3021 (aromatic C-H), 2954, 2844 (aliphatic C-
H), 1643 (C=O) and 1616 (C=C); UV-Vis (MeOH):
λmax(nm) 334, 238; H-NMR (500 MHz, CDCl ): δ 8.28
(2H, d, J = 8.4 Hz, H-8), 7.86 (2H, dd, J = 2.5, 7.9 Hz,
H-10), 7.74 (2H, d, J = 8.0 Hz, H-11), 7.59 (2H, td,
0 0
Jm,o = 1.8, 7.6 Hz, H-9), 7.50 (4H, t, J = 7.4 Hz, H-2 , 6 ),
o
7.44 (6H, m, H-3 , 4 , 5 ), 7.38 (4H, s, H-2 , 3 , 4 , 5 ),
6.30 (2H, brs, H-1), 5.81 (2H, d, Jvic = 2.5 Hz, H-4), 5.00
(2H, d, J5,4a = 12.3 Hz, H-5), 3.80 (2H, m, H-4a), 2.82
(4H, m, H-2a); C-NMR (125 MHz, DMSO-d ): δ 178.72
(C=O), 155.44 (C-11a), 147.65 (C-12a), 143.82 (C-6a),
139.30 (C-7a), 138.66 (C-1 , 4 ), 133.42 (C-12b), 131.23
0 0 0
(C-1 ), 129.75 (C-3), 129.05 (C-10), 127.82 (C-2 , 6 ),
0
0
−1
(
2H, dd, J
m,o
000
0
0
0
5
0
00
000
000
1
(
(
(
(
o
3
o
m,o
o
1
3
4H, m, H-2a);
6
0
0
0
000
000
000
000
1
(
1
(
1
(
(
0
00
000
0
000
0
0
0
0
0
13
6
0
00
000
0
00
000 000
C-2 ), 124.31 (C-1), 122.72 (C-4), 118.24 (C-11), 74.96
C-5), 39.26 (C-4a), 35.64 (C-2a); ESI-MS: m/z Calcu-
lated for C H O : 730.24 [M] ; Found: 730.44 [M]
(74%); Anal. calc. for
C H O : C, 82.18%; H, 4.69%; Found: C,
+
+
000
000
000
000
0
0
0
127.34 (C-2 , 3 , 5 , 6 ), 126.93 (C-3 , 5 ), 126.89 (C-4 ),
126.16 (C-8), 124.83 (C-9), 124.09 (C-1), 123.56 (C-4),
119.23 (C-11), 74.64 (C-5), 40.15 (C-4a), 34.39 (C-2a); ESI-
5
0
34 6
+
(
100%), 731.44 [M + 1]
5
0
34 6
+
8
1.85%; H, 4.71%.
MS: m/z Calculated for C H O : 730.24 [M] ; Found:
50
34 6

NISA AND YUSUF
17
+
+
000
000
7
31.36 [M + 1] (100%), 732.36 [M + 2] (66%); Anal.
(C-3 , 5 ), 124.62 (C-1), 121.22 (C-4), 116.58 (C-11),
calc. for C H O : C, 82.18%; H, 4.69%; Found: C,
78.03 (C-5), 39.73 (C-4a), 35.72 (C-2a); ESI-MS: m/z Cal-
50
34 6
+
8
2.50%; H, 4.67%.
culated for C H NO : 731.23 [M] ; Found: 732.58 [M
4
9
33
6
+
+
+
+
1] (100%), 754.46 [M + Na] (49%), 755.46 [M + Na
1] (38%); Anal. calc. for C H NO : C, 80.42%; H,
+
49
33
6
5
5
5
.4.14 | (S)-5-(4-(((R)-7-Oxo-3-phenyl-
,7-dihydroisochromeno[4,3-b]chromen-
-yl)methyl)benzyl)-3-phenylisochromeno
4.55%, N, 1.91%; Found: C, 80.74%; H, 4.57%, N, 1.90%.
[
4,3-b]chromen-7(5H)-one 5g
5.4.16 | (S)-5-((6-(((R)-7-Oxo-3-phenyl-
5
,7-dihydroisochromeno[4,3-b]chromen-
ꢀ
Light brown solid; yield 40%; m.p. 215-217 C; IR (KBr)
5-yl)methyl)pyridine-2-yl)methyl)-
3-phenylisochromeno[4,3-b]chromen-7
(5H)-one 5h
−
1
cm :3052, 3026 (aromatic C-H), 2958, 2882 (aliphatic C-
H), 1632 (C=O) and 1598 (C=C); UV-Vis (MeOH):
λmax(nm) 350, 291; H-NMR (500 MHz, CDCl ): δ 8.22
2H, d, J = 8.2 Hz, H-8), 7.99 (4H, dd, J = 0.8, 7.3 Hz,
H-1, 2), 7.80 (2H, td, Jm,o = 2.8, 7.5 Hz, H-10), 7.75 (4H,
m, H-4, 11), 7.67 (4H, dd, Jm,o = 2.1, 8.0 Hz, H-2 , 6 ),
.56 (2H, t, J = 7.6 Hz, H-9), 7.46 (6H, m, H-3 , 4 , 5 ),
.36 (4H, s, H-2 , 3 , 4 , 5 ), 5.94 (2H, s, H-5); C-NMR
1
3
ꢀ
(
Light brown solid; yield 44%; m.p. 228-230 C; IR (KBr)
cm :3058, 3037 (aromatic C-H), 2944, 2879 (aliphatic C-
H), 1646 (C=O) and 1605 (C=C); UV-Vis (MeOH):
λmax(nm) 348, 282; H-NMR (500 MHz, DMSO-d ): δ
o
p,o
−
1
0
0
0
13
0
0
1
7
7
o
6
0
00
000
000
000
8.27 (2H, dd, Jm,o = 2.8, 8.2 Hz, H-8), 7.94 (4H, d,
(
125 MHz, CDCl ): δ 180.99 (C=O), 155.28 (C-11a),
55.04 (C-12a), 143.64 (C-6a), 140.22 (C-4a), 139.85 (C-
Jo = 8.0 Hz, H-1, 2), 7.83 (2H, td, Jm,o = 2.0, 8.6 Hz, H-
3
0
1
7
1
1
5
1
7
+
10), 7.78 (4H, m, H-4, 11), 7.69 (4H, d, J = 8.2 Hz, H-2 ,
o
0
00
000
0
0
000
a), 137.55 (C-1 , 4 ), 133.52 (C-12b), 130.55 (C-1 ),
29.27 (C-3), 129.08 (C-10), 128.31 (C-4), 127.73 (C-1, 2),
6 ), 7.64 (3H, m, H-9, 4 ), 7.57 (6H, dd, J
= 2.9,
m,o
0
0
0
000
000
8.6 Hz, H-3 , 4 , 5 ), 7.47 (2H, d, J = 8.0 Hz, H-3 , 5 ),
6.00 (2H, s, H-5); C-NMR (125 MHz, CDCl ): δ 182.09
(C=O), 157.33 (C-11a), 156.35 (C-12a), 155.90 (C-2 , 6 ),
o
0
0
000
000
000
000
0
13
27.59 (C-2 , 6 ), 127.26 (C-2 , 3 , 5 , 6 ), 125.73 (C-3 ,
), 124.97 (C-8), 124.28 (C-4 ), 122.97 (C-9), 118.76 (C-
3
0
0
000
000
1), 76.92 (C-5); ESI-MS: m/z Calculated for C H O :
143.73 (C-6a), 140.56 (C-4a), 140.48 (C-7a), 133.39 (C-
5
0
30 6
+
+
000
0
26.20 [M] ; Found: 726.38 [M] (100%), 727.38 [M
1] (71%), 728.38 [M + 2] (34%); Anal. calc. for
12b), 133.23 (C-4 ), 129.83 (C-1 ), 129.67 (C-3), 129.21
(C-10), 129.00 (C-4), 128.63 (C-1), 128.27 (C-2), 127.72
+
+
0 0 0 0 0
C H O : C, 82.63%; H, 4.16%; Found: C,
8
(C-2 , 6 ), 127.40 (C-3 , 5 ), 127.07 (C-4 ), 125.88 (C-8),
50
30 6
000 000
124.63 (C-9), 124.30 (C-3 , 5 ), 118.24 (C-11), 80.73 (C-
2.96%; H, 4.18%.
+
5
); ESI-MS: m/z Calculated for C H NO : 727.20 [M] ;
Found: 728.32 [M + 1] (100%), 729.32 [M + 2] (28%),
751.14 [M + Na + 1]
49 29 6
+
+
+
5
3
.4.15 | (4aS,5R)-5-(6-((4aR,5S)-7-Oxo-
-phenyl-2,4a,5,7-tetrahydroisochromeno
(22%); Anal. calc. for
C H NO : C, 80.87%; H, 4.02%, N, 1.92%; Found: C,
49
29
6
[
4,3-b]chromen-5-yl)pyridine-2-yl)-
-phenyl-4a,5-dihydroisochromeno[4,3-b]
chromen-7(2H)-one 4h
80.54%; H, 4.04%, N, 1.93%.
3
ACKNOWLEDGMENTS
One of the authors Ms. Shehneela Nisa wishes to express
her appreciation to UGC, New Delhi (India) for the
award of Junior Research Fellowship under the Maulana
Azad National Fellowship Scheme (MANF-2018-19-PUN-
91279). Moreover, we would like to acknowledge the
SAIF, Panjab University, Chandigarh, India for providing
the H-NMR and C-NMR spectra. We are also thankful
to IIT, Ropar, Punjab, India for recording the ESI-MS
spectra of the newly prepared products.
ꢀ
Light yellow solid; yield 30%; m.p. 200-202 C; IR (KBr)
−
1
cm :3062, 3015 (aromatic C-H), 2938, 2850 (aliphatic C-
H), 1635 (C=O) and 1613 (C=C); UV-Vis (MeOH):
λmax(nm) 324, 243; H-NMR (500 MHz, DMSO-d ): δ 8.26
3H, m, H-8, 4 ), 7.82 (2H, d, J = 7.0 Hz, H-10), 7.75
2H, td, J = 2.3, 8.0 Hz, H-11), 7.66 (2H, d, J = 7.6 Hz,
H-3 , 5 ), 7.56 (2H, m, H-9), 7.46 (4H, d, J = 7.7 Hz, H-
0 0 0 0
, 6 ), 7.40 (6H, t, J = 7.7 Hz, H-3 , 4 , 5 ), 6.26 (2H, brs,
o
1
6
0
00
(
(
o
1
13
m,o
o
000
000
o
0
2
H-1), 5.72 (2H, d, Jvic = 3.0 Hz, H-4), 5.08 (2H, d,
J5,4a = 12.6 Hz, H-5), 3.85 (2H, m, H-4a), 2.74 (4H, m, H-
ORCID
1
3
2
a); C-NMR (125 MHz, CDCl ): δ 179.53 (C=O), 156.66
Mohamad Yusuf https://orcid.org/0000-0003-4138-8710
3
000 000
(C-11a), 155.92 (C-2 , 6 ), 150.59 (C-12a), 142.85 (C-6a),
000
1
1
40.91 (C-7a), 139.38 (C-12b), 137.78 (C-4 ), 133.46 (C-
REFERENCES
0
0
0
), 129.99 (C-3), 129.70 (C-10), 128.91 (C-2 , 6 ), 127.97
[1] J. A. Dantas, J. T. M. Correia, M. W. Paixao, A. G. Correa,
0
0
0
(C-3 , 5 ), 127.58 (C-4 ), 126.50 (C-8), 125.59 (C-9), 124.99
ChemPhotoChem 2019, 3, 506.

18
NISA AND YUSUF
[
2] V. G. Melekhina, A. N. Komogortsev, B. V. Lichitsky, V. S.
Mityanov, A. N. Fakhrutdinov, A. A. Dudinov, M. M.
Krayushkin, Tetrahedron Lett. 2019, 60, 151080.
3] N. Kaur, Curr. Org. Synth. 2018, 15, 298.
4] F. Politano, G. Oksdath-Mansilla, Org. Process. Res. Dev. 2018,
[27] C. F. Silva, D. C. Pinto, A. M. Silva, ChemMedChem 2016, 11,
2252.
[28] V. S. Dofe, A. P. Sarkate, D. K. Lokwani, D. B. Shinde, S. H.
Kathwate, C. H. Gill, J. Heterocyclic Chem. 2017, 54, 2678.
[29] R. Jiao, F. Xu, X. Huang, H. Li, W. Liu, H. Cao, D. Li,
J. Enzyme Inhib. Med. Chem. 2020, 35, 759.
[
[
2
2, 1045.
[
[
[
5] R. Khanna, A. Dalal, R. Kumar, R. C. Kamboj, Photochem.
[30] C. Demetgul, N. Beyazit, Carbohydr. Polym. 2018, 181, 812.
[31] C. F. Silva, V. F. Batista, D. C. Pinto, A. M. Silva, Expert Opin.
Drug Discovery 2018, 13, 795.
[32] R. S. Keri, S. Budagumpi, R. K. Pai, R. G. Balakrishna, Eur.
J. Med. Chem. 2014, 78, 340.
[33] M. Saigal, P. Irfan, M. Khan, M. M. K. Abid, ACS Omega 2019,
4, 16794.
[34] T. U. Kumar, D. Roy, A. Bhattacharya, Tetrahedron Lett. 2019,
60, 1895.
Photobiol. Sci. 2015, 14, 2195.
6] R. C. Kamboj, P. Jindal, R. Arora, A. Chaudhary, S. Khullar,
S. K. Mandal, Chem. Sci. Rev. Lett. 2014, 3, 231.
7] R. C. Kamboj, D. Kumar, R. Arora, S. Berar, G. Sharma,
J. Heterocyclic Chem. 2013, 50, E200.
8] J. Cossy, A. Guerinot, Adv. Heterocycl. Chem. 2016, 119, 107.
9] J. Saranya, F. Benhiba, N. Anusuya, R. Subbiah, A. Zarrouk, S.
Chitra, Colloid Surface A 2020, 603, 125231.
[
[
[
[
10] A. Romdhane, H. B. Jannet, Arab. J. Chem. 2017, 10, S3128.
11] M. Zabihzadeh, A. Omidi, F. Shirini, H. Tajik, M. S. N.
Langarudi, J. Mol. Struct. 2020, 1206, 127730.
12] D. Tejedor, S. Delgado-Hernandez, R. Diana-Rivero, A. Diaz-
Diaz, F. Garcia-Tellado, Molecules 2019, 24, 2904.
13] P. Singh, P. Yadav, A. Mishra, S. K. Awasthi, ACS Omega
[35] M. Yusuf, I. Solanki, P. Jain, R. Kumar, Arab. J. Chem. 2019,
12, 1197.
[36] A. Dalal, R. Khanna, P. Kumar, R. C. Kamboj, Photochem.
Photobiol. Sci. 2017, 16, 672.
[37] M. Sisa, S. L. Bonnet, D. Ferreira, J. H. Van der Westhuizen,
Molecules 2010, 15, 5196.
[38] S. C. Gupta, M. Yusuf, S. Sharma, A. Saini, S. Arora, R. C.
Kamboj, Tetrahedron 2004, 60, 8445.
[39] S. C. Gupta, M. Yusuf, S. Arora, R. C. Kamboj, Tetrahedron
2003, 59, 3609.
[40] M. Yusuf, I. Solanki, P. Jain, Arab. J. Chem. 2017, 10, S971.
[41] M. Yusuf, I. Solanki, P. Jain, Sci. World J. 2012, 2012, 1.
[42] M. Yusuf, R. Kumar, S. C. Gupta, J. Heterocyclic Chem. 2008,
45, 963.
[43] R. Kumar, M. Yusuf, Arkivoc 2007, 16, 227.
[44] R. Kumar, M. Yusuf, Ind. J. Chem. Sec. B 2010, 49B, 216.
[45] S. Nisa, M. Yusuf, Ind. J. Chem. Sec. B 2020, 59B, 420.
[46] K. S. Pandey, N. Khan, Arch. Pharm. Chem. Life Sci. 2008,
341, 418.
[
[
[
[
2
020, 5, 4223.
14] D. Kumar, P. Sharma, H. Singh, K. Nepali, G. K. Gupta, S. K.
Jain, F. Ntie-Kang, RSC Adv. 2017, 7, 36977.
15] A. A. F. Mostafa, C. Sathish Kumar, A. A. Al-Askar, S. R.
Sayed, R. Surendra Kumar, A. Idhayadhulla, RSC Adv. 2019, 9,
2
5533.
16] M. Honarmand, A. Tzani, A. Detsi, J. Mol. Liq. 2019, 290,
11358.
[
[
[
[
[
[
[
1
17] K. Tanaka, Y. Shigematsu, M. Sukekawa, Y. Hoshino, K.
Honda, Tetrahedron Lett. 2016, 57, 5914.
18] X. Lu, Q. Dong, X. Dong, W. Zhao, Tetrahedron 2015, 71,
4
061.
19] A.
Hadadzahmatkesh, Arab. J. Chem. 2017, 10, S2213.
20] H. M. Albuquerque, C. M. Santos, J. A. Cavaleiro, A. M. Silva,
New J. Chem. 2018, 42, 4251.
A.
Mohammadi,
M.
R.
Asghariganjeh,
A.
SUPPORTING INFORMATION
Additional supporting information may be found online
in the Supporting Information section at the end of this
article.
21] M. Z. Li, Q. Tong, W. Y. Han, S. Y. Yang, B. D. Cui, N. W.
Wan, Y. Z. Chen, Org. Biomol. Chem. 2020, 18, 1112.
22] S. R. Salpage, L. S. Donevant, M. D. Smith, A. Bick, L. S.
Shimizu, J. Photochem. Photobiol. A 2016, 315, 14.
23] C. M. Santos, V. L. Silva, A. Silva, Molecules 2017, 22, 1665.
24] H. Ishikawa, N. Uemura, R. Taira, K. Sano, Y. Yoshida, T.
Mino, M. Sakamoto, Tetrahedron 2019, 75, 3911.
25] T. Shokol, O. Lozinski, N. Gorbulenko, V. Khilya, Fr.-Ukr.
J. Chem. 2017, 5, 68.
[
[
How to cite this article: Nisa S, Yusuf M. Novel
bisbenzopyronopyran derivatives: photochemical
synthesis and their in-vitro antimicrobial studies.
J Heterocyclic Chem. 2020;1–18. https://doi.org/10.
[
[
1002/jhet.4171
26] Y. Y. Jiang, F. X. Guo, L. X. Chen, L. L. Xu, W. Zhang, B. Liu,
Fitoterapia 2019, 135, 114.