Microwave assisted synthesis and photophysical properties of blue emissive 2-amino-3-carboxamide-1,1′-biaryls and 4-(arylamino)-[1,1′-biphenyl]-3-carboxamides via Suzuki and Chan-Evans-Lam coupling

Article abstract of DOI:10.1016/j.dyepig.2019.108015

An efficient microwave assisted synthesis of 2-amino-3-carboxamide-1,1′-biaryls derivatives 4a-p and terphenyl derivative 5a from 2-amino-5-iodobenzamide 2a, 2-amino-3,5-diiodobenzamide 2b and (het)aryl boronic acids via Suzuki coupling has been achieved. Synthetic utility of the product 4-amino-4′-cyano-[1,1′-biphenyl]-3-carboxamide 4j has been demonstrated for the synthesis of 4-(aryl amino)-[1,1′-biphenyl]-3-carboxamide derivatives 10a-c via Chan-Evans-Lam coupling reaction. Furthermore, 4-(4′-oxo-3′, 4′-dihydro-1′H-spiro[fluorene-9,2′-quinazolin]-6′-yl)benzonitrile 12a was obtained from biaryl derivative 4j and fluorenone 11a and 6(4- methoxyphenyl)2-(ferrocenyl) quinazolin-4(3H)-one 12b from biaryl derivative 4k and ferrocenealdehyde 11b using phosphotungstic acid as green catalyst and solvent free microwave irradiation condition. Remarkably, all the synthesized 2-amino-3-carboxamide-1,1′-biaryls and 4-(aryl amino)-[1,1′-biphenyl]-3-carboxamide derivatives 4a-p showed luminescence in the blue region with large Stokes shift. Significantly, 2-amino-3-carboxamide-1,1′-biaryls 4d and 4j showed high fluorescence quantum yields (Φ_f) 0.54 and 0.84, respectively.

Full text of DOI:10.1016/j.dyepig.2019.108015

Journal Pre-proof
Microwave assisted synthesis and photophysical properties of blue emissive 2-
amino-3-carboxamide-1,1′-biaryls and 4-(arylamino)-[1,1′-biphenyl]-3-carboxamides
via Suzuki and Chan-Evans-Lam coupling
Motakatla Novanna, Sathananthan Kannadasan, Ponnusamy Shanmugam
PII:
S0143-7208(19)30933-7
DOI:
https://doi.org/10.1016/j.dyepig.2019.108015
DYPI 108015
Reference:
To appear in: Dyes and Pigments
Received Date: 25 April 2019
Revised Date: 17 October 2019
Accepted Date: 1 November 2019
Please cite this article as: Novanna M, Kannadasan S, Shanmugam P, Microwave assisted synthesis
and photophysical properties of blue emissive 2-amino-3-carboxamide-1,1′-biaryls and 4-(arylamino)-
[1,1′-biphenyl]-3-carboxamides via Suzuki and Chan-Evans-Lam coupling, Dyes and Pigments (2019),
doi: https://doi.org/10.1016/j.dyepig.2019.108015.
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Graphical Abstract
Microwave assisted synthesis of 2-amino-3-carboxamide 1, 1'-biaryls derivatives via Suzuki coupling, chemo selective N-arylation of biaryl
derivatives via Chan-Evans-Lam coupling has been reported. Evaluation of photophysical properties showed luminescence in the blue region with
large Stokes shift and high quantum yields.
Microwave assisted synthesis and photophysical
properties of blue emissive 2-amino-3-carboxamide
1, 1'-biaryls and 4-(arylamino)-[1, 1'-biphenyl]-
Leave this area blank for abstract info.
3-carboxamides via Suzuki and Chan-Evans-Lam coupling
Motakatla Novannaa, Sathananthan Kannadasana* and Ponnusamy Shanmugamb*

Dyes and Pigments
journal homepage: www.elsevier.com
Microwave assisted synthesis and photophysical properties of blue emissive
2-amino-3-carboxamide-1,1'-biaryls and 4-(arylamino)-[1,1'-biphenyl]-3-
carboxamides via Suzuki and Chan-Evans-Lam coupling
Motakatla Novannaa, Sathananthan Kannadasana* and Ponnusamy Shanmugamb*
aDepartment of Chemistry, School of Advanced Science, Vellore Institute of Technology, Vellore-632014, Tamil Nadu, India; E mail: kannadasan.s@vit.ac.in
bOrganic and Bio-Organic Chemistry Division, Council of Scientific and Industrial Research (CSIR)-Central Leather Research Institute (CLRI), Adyar, Chennai-
600020, India; Fax: (+) 91-44-24911589; Phone: (+91)-44-24437130; E-mail: shanmu196@rediffmail.com
ARTICLE INFO
ABSTRACT
Article history:
Received
Received in revised form
Accepted
Abstract: An efficient microwave assisted synthesis of 2-amino-3-carboxamide-1,1'-
biaryls derivatives 4a-p and terphenyl derivative 5a from 2-amino-5-iodobenzamide 2a, 2-
amino-3,5-diiodobenzamide 2b and (het)aryl boronic acids via Suzuki coupling has been
achieved. Synthetic utility of the product 4-amino-4'-cyano-[1,1'-biphenyl]-3-carboxamide
4j has been demonstrated for the synthesis of 4-(aryl amino)-[1,1'-biphenyl]-3-
carboxamide derivatives 10a-c via Chan-Evans-Lam coupling reaction. Furthermore, 4-
(4'-oxo-3', 4'-dihydro-1'H-spiro[fluorene-9,2'-quinazolin]-6'-yl)benzonitrile 12a was
obtained from biaryl derivative 4j and fluorenone 11a and 6(4- methoxyphenyl)2-
(ferrocenyl) quinazolin-4(3H)-one 12b from biaryl derivative 4k and ferrocenealdehyde
11b using phosphotungstic acid as green catalyst and solvent free microwave irradiation
condition. Remarkably, all the synthesized 2-amino-3-carboxamide-1,1'-biaryls and 4-(aryl
amino)-[1,1'-biphenyl]-3-carboxamide derivatives 4a-p showed luminescence in the blue
region with large Stokes shift. Significantly, 2-amino-3-carboxamide-1,1'-biaryls 4d and 4j
showed high fluorescence quantum yields (Φf) 0.54 and 0.84, respectively.
Available online
Keywords:
Aminoamides
(Het)aryl boronic acids
Biaryls
Suzuki coupling
Chan-Evans-Lam coupling
Fluorescence quantum yield
@ 2019 Elsevier Ltd. All rights reserved
.
1. Introduction
starting material for the synthesis of various heterocyclic
compounds and natural products of biological interest [28-33].
Recently, we have reported the synthesis of 2ˈ-spiro and 2, 3-
dihydro quinazolinone and 2-methylamino benzamide
derivatives from aryl and heteroaryl 2-amino amides [34].
Biaryl core structures have been found as backbone of the
natural products and biomolecules [1-6] (Fig. 1). The
electronic structure of biaryls constitutes diverse applications
include in asymmetric synthesis as chiral ligands [7,8], as
blue emissive layers in organic light-emitting diodes [9-11]
(OLEDs), as optical brighteners [12], as synthons for liquid
crystals [13] and as spacers in polymerization [14,15].
Utilizing C-C bond formation reactions, methods for the
synthesis of biaryls have been developed include Ullmann
reaction using copper as catalyst [16,17], other catalysts such
as nickel, zinc, manganese, gold, palladium and through homo
coupling of aryl Grignard reagent [18], from arynes [19] and
metal free synthesis [20]. The Suzuki cross coupling of aryl
halides with aryl boronic acids catalyzed by palladium is most
utilized reactions in synthetic chemistry for numerous
heterocyclic compounds, including biaryl derivatives [21,22].
Chan-Evans-Lam coupling [23] is an effective cross-coupling
reaction of amines/alcohols and other nucleophiles with
arylboronic acids using copper salts as catalyst to form
secondary amines or aryl ethers. Chan-Lam coupling proceeds
under mild reaction conditions, thus having an advantage over
Buchwald-Hartwig amination [24,25] and Ullmann-Goldberg
reaction[26,27]. 2-Aminobenzamide has been utilised as a
Fig. 1 Natural products and drugs with biaryl backbone

Microwave (MW) irradiation method for the cross
coupling reaction is a complementary tool to conventional
cross coupling reactions [35-37]. A number of carbocyclic
and heterocyclic compounds have been synthesized via MW
irradiation pathways with faster reaction times, higher yields
and possible minimum by-products. An integrated catalysis
arylation pathway via regiodivergent enzymatic C-H
activation method is known for biaryl synthesis [38]. Despite
biaryls have largely used as synthons in organic chemistry,
however, functionalization of biaryls appended with amides
is limitedly explored.
assignments; Coupling constants (J) were reported in Hertz (Hz).
All 13C spectra are proton-decoupled. Multiplicity is indicated as
follows: s (singlet), d (doublet), t (triplet), q (quartet), m
(multiplet), dd (doublet of doublet), br s (broad singlet). FTIR
spectra were recorded on a Perkin-Elmer RX-IFT-IR and
absorbencies are reported in cm-1. ESI HRMS were recorded
using Waters(R) Micromass(R) Q-TOF MicroTM Mass
Spectrometer. Yields refer to quantities obtained after
chromatography Yields refer to quantities obtained after
purification by column chromatography. Absorption spectra were
recorded using Cary100 Bio UV-Vis spectrophotometer. Steady-
state fluorescence spectra were recorded on SHIMADZU RF-
6000 spectrofluorophotometer by excitation at the respective
absorption maxima. Quantum yields of compounds was
estimated by comparison with the known quantum yields of
Quinine sulphate in 0.5 M H2SO4 solution (Φ=0.54) at an
excitation wavelength of 366 nm using the following equation.
Hence, herein we report the synthesis and evaluation of
photophysical
properties
of
2-amino-3-carboxamide
substituted 1,1'-biaryls 4 and 5 through MW assisted Suzuki
coupling reaction. The biaryls 4 and 5 were synthesised from
and 2-amino-5-iodo benzamide 2a and 2-amino-3,5-diiodo
benzamide 2b. Further, to demonstrate the synthetic utility of
the biaryls 4, compounds 4-(aryl amino)-[1,1'-biphenyl]-3-
carboxamides 10 were obtained by Chan-Evans-Lam coupling
reaction of 4j whereas compound 12a was obtained via HPW
catalysed spiro annulation reaction of 4j (Scheme 1).
Φ = ΦR . I/IR . ODR/OD . n2/n2
R
where Φ is the quantum yield, I is the integrated intensity, OD
is the optical density, and n is the refractive index. The subscript
R refers to the Quinine sulphate.
2.2. Synthesis
Previous work:
Br
Halogenase,
FAD, NADH,
O2, NaBr, 12 h
2.2.1. Synthesis of 2-amino-5-iodobenzamide 2a and 2-amino-3,
5-diiodobenzamide 2b [39]:
[Pd], Ligand
Ar-B(OH)2, 24 h
NH2
NH2
Ref. 38
NH2
O
NH2
NH2
O
To a stirred solution of anthranilamide 1 (1.0 g, 1.0 equiv.)
and iodine (4.6g, 2.5 equiv.) in water (50 mL), sodium
bicarbonate (NaHCO3) (0.9g, 1.5 equiv.) was added. The mixture
was stirred at RT for 12 h. After completion of the reaction
(monitored by TLC), the reaction mixture was extracted with
EtOAc and washed with HCl (0.25 M, 50 mL) followed by
saturated brine and water. The combined organic solvent was
dried over anhydrous Na2SO4 and the solvent was removed under
vacuum. The crude mixture was purified by a column of silica
gel by gradient elution using EtOAc: hexane (20:80) yielded 2-
amino-5-iodobenzamide 2a in 85% yield and 2-amino-3,5-
diiodobenzamide 2b in 10% yield.
NH2
O
Membrane
This work
O
I
NH2
R
O
[Pd],
Ar-B(OH)2 (3a-r)
Fig. 2
NH2
(85%)
I2 , H2O
NaHCO3
NH2
2a
NH2
O
NH2
µW, 10 min.
NH2
RT, 12h
I
NH2
O
1
NH2
NH2
2b (10%)
NH2
4a-p from 2a and 3a-p
R = Aryl, Me, OMe, NH2, CN, Cl, F, H
O
5a
2b
3a
from
CN
and
I
4j
Synthetic transformations of
CN
NC
CuCl/TEA/MeOH
O
3e, m,n
Ar-B(OH)2
(
)
H3PW12O40
NH
Fig. 2
11a
Fluorenone (
)
Chan-Ivans-Lam
Coupling
NH2
N
H
NH2
2.2.2. General procedure for preparation of 2-amino-3-
µW, 3 min
R
NH
O
carboxamide 1,1'-biaryls 4a-p and 5a by Suzuki coupling:
NH2
O
12a
4j
10a-c (
R= Ph, Me, H)
A mixture of compound 2a or 2b (0.191 mmol), arylboronic
acids 3 (0.229 mmol), Pd(dppf)Cl2.DCM (8 mg, 0.0095 mmol)
and 0.5 N K2CO3 (1 mL, 0.5 mmol) in 4 mL of dioxane-MeOH
(3:1) was microwave irradiated (power mode) at 200 W for 10
min. After completion of the reaction (TLC), the solvent was
removed in vacuo, and the residue was extracted with EtOAc and
washed with HCl (0.25 M, 20 mL) followed by saturated brine.
The organic layer was dried over anhydrous Na2SO4 and purified
through a silica gel column chromatography by gradient elution
using EtOAc:hexane to afford compounds 4a-4p and 5a in very
good yields.
Scheme 1 Iodination of 1, Suzuki coupling of 2a,b and
synthetic transformations of 4j
2. Experimental
2.1. Materials and methods
All the reactions were carried out in oven-dried glassware. CEM
Discover-300 microwave synthesiser was used for all the
microwave irradiation reactions. 2-Aminobenzamide, (het)aryl
boronic acids, and Pd(0) & Pd(II)-catalysts were purchased from
Sigma Aldrich and used as received. Progress of reactions was
monitored by Thin Layer Chromatography (TLC) using pre-
coated Merck TLC plates (Merck 60 F254). The compounds
were visualized with a UV light at 254 nm and by staining with
iodine, while purification of crude compounds was done by
column chromatography using Silica gel (Mesh size 100-200).
The structure of new compounds was established by
2.2.3. Synthesis of 4'-cyano-4-(arylamino)-[1,1'-biphenyl]-3-
carboxamides 10a-c by Chan-Evans-Lam coupling:
To
a
mixture of 4-amino-4'-cyano-[1,1'-biphenyl]-3-
carboxamide 4j (0.210 mmol), arylboronic acids 3 (0.252 mmol)
in methanol was added cuprous chloride (CuCl) (0.0315 mmol),
and Et3N (0.105 mmol) and stirred at RT for 4h under ambient
conditions. After completion of the reaction, the reaction mixture
was filtered through celite pad and the filtrate was concentrated
and purified by silica gel column chromatography using EtOAc:
hexane as eluent to afford 4'-cyano-4-(arylamino)-[1,1'-
biphenyl]-3-carboxamides 10a-c in good yields.
spectroscopic data such as FTIR, H NMR, 13C NMR, DEPT-
135 and HRMS. The NMR spectra were recorded on Bruker-400
1
1
MHz NMR spectrometer (400 MHz for H NMR and 100 MHz
for 13C NMR) with CDCl3 or (CD3)2SO as the solvent and TMS
as internal reference. Integrals are in accordance with

2.2.4. Experimental procedure for synthesis of spiro and cyclic
quinazolinones 12a and 12b:
7.33 (m, 4H), 7.30 (dd, J = 8.3, 2.0 Hz, 2H), 6.71 (d, J = 8.4 Hz,
1H), 5.82 (br s, 4H); 13C NMR (100 MHz, CDCl3): δ 171.1,
148.8, 139.4, 134.8, 133.9, 131.8, 129.4, 128.8, 128.4, 127.5,
126.8, 126.1, 125.8, 125.5, 117.4, 113.7; HRMS-ESI: Calcd. for
C17H12NO [M-NH2]+ m/z: 246.0913; Found 246.0915.
A slurry made of biaryls 4j or 4k (1.0 equiv.) and carbonyl
compounds 11a or 11b (1.2 equiv.) and 50% w/w
phosphotungstic acid (HPW) was microwave irradiated (standard
mode) (50% w/w) at 200 W for 3 min. After the completion of
the reaction (monitored by TLC), HPW was filtered off using
celite bed. The crude product was purified on a silica gel column
chromatography to afford the spiro and cyclic quinazolinones
12a and 12b in good yields, respectively.
2.3.6. 2-Amino-5-(naphthalen-2-yl)benzamide (4f): Brown
powder: 38 mg, 77% yield; Rf (40% EtOAc-Hexane): 0.49,
MP:156-161 οC; FTIR (KBr) νmax: 3407, 2922, 1643, 1405, 1265,
1
1167, 808,746 cm-1; H NMR (400 MHz, DMSO-d6) δ 8.16 (s,
1H), 8.03 (d, J = 2.2 Hz, 2H), 7.97 – 7.86 (m, 4H), 7.68 (dd, J =
8.6, 2.2 Hz, 1H), 7.48 (dddd, J = 16.2, 8.0, 6.9, 1.4 Hz, 2H), 7.19
(s, 1H), 6.84 (d, J = 8.6 Hz, 1H), 6.76 (s, 2H); 13C NMR (100
MHz, DMSO-d6): δ 171.8, 150.3, 137.8, 133.9, 132.0,130.9,
128.6, 128.2, 127.9, 127.6, 126.7, 126.5, 125.8, 125.2, 123.7,
117.6, 114.5; HRMS-ESI: Calcd. for C17H12NO [M-NH2]+ m/z:
246.0913; Found 246.0901.
2.3. Spectroscopic data of synthesized compounds
2.3.1.
2-Amino-5-(dibenzo[b,d]furan-4-yl)benzamide
(4a):
Brown powder: 48 mg, 85% yield; Rf (40% EtOAc-Hexane):
ο
0.49, MP:182-187 C; FTIR (KBr) νmax: 3372, 3193, 1639, 1566,
1444, 1400, 1315, 1263, 1186, 795, 747, 662 cm-1; 1H NMR (400
MHz, DMSO-d6) δ 8.16 (d, J = 7.1 Hz, 1H), 8.07-8.02 (m, 2H),
7.97 (s, 1H), 7.82 (dd, J = 8.6, 2.1 Hz, 1H), 7.76-7.70 (m, 2H),
7.55-7.50 (m, 1H), 7.43 (dt, J = 14.3, 7.5 Hz, 2H), 7.19 (s, 1H),
6.90 (d, J = 8.6 Hz, 1H), 6.78 (s, 2H); 13C NMR (100 MHz,
DMSO-d6): δ 171.8, 155.8, 152.9, 150.3, 132.7, 129.2, 128.0,
126.6, 125.7, 124.6, 124.1, 124.0, 123.5, 122.3, 121.6, 119.3,
117.1, 114.6, 112.3; HRMS-ESI: Calcd. for C19H14N2O2 [M+H]+
m/z: 303.1134; Found 303.1132 and Calcd. for C19H12NO2 [M-
NH2]+ m/z: 286.0868; Found 286.0870.
2.3.7. 4-Amino-[1,1':4',1''-terphenyl]-3-carboxamide (4g): White
powder: 45 mg, 82% yield; Rf (40% EtOAc-Hexane): 0.49,
MP:214-217 οC; FTIR (KBr) νmax: 3360, 2923, 1632, 1482, 1388,
1275, 1162, 817, 763, 688, 543 cm-1; 1H NMR (400 MHz,
DMSO-d6) δ 8.01 (br s, 1H), 7.94 (d, J = 2.1 Hz, 1H), 7.77 – 7.54
(m, 2H), 7.70 (dd, J = 8.2, 1.5 Hz, 4H), 7.56 (dd, J = 8.6, 2.1 Hz,
1H), 7.47 (dd, J = 10.5, 4.8 Hz, 2H), 7.37 – 7.33(m, 1H), 7.15 (br
s, 1H), 6.81 (d, J = 8.6 Hz, 1H), 6.73 (br s, 2H); 13C NMR (100
MHz, DMSO-d6): δ 171.8, 150.3, 140.3, 139.6, 138.1, 130.5,
129.4, 127.7, 127.4, 127.2, 126.9, 126.5, 126.2, 117.5, 116.9,
114.4; HRMS-ESI: Calcd. for C19H16N2O [M+H]+ m/z: 289.1341;
Found 289.1340 and Calcd. for C19H14NO [M-NH2]+ m/z:
272.1075; Found 272.1092.
2.3.2. 2-Amino-5-(dibenzo[b,d]thiophen-2-yl)benzamide (4b):
Brown powder: 40 mg, 66% yield; Rf (40% EtOAc-Hexane):
0.47, MP:174-179 οC; FTIR (KBr) νmax
: 3446, 3330, 3182,
3052, 2920, 1654, 1495, 1463, 1428, 1393, 1313, 1257, 1166,
1116, 1020, 800, 719, 630, 537 cm-1; 1H NMR (400 MHz,
DMSO) δ 8.64 (br s, 1H), 8.48 – 8.46 (m, 1H), 8.02 (dt, J = 7.2,
5.5 Hz, 4H), 7.84 (dd, J = 8.4, 1.7 Hz, 1H), 7.70 (dd, J = 8.6, 2.1
Hz, 1H), 7.52 (dt, J = 9.9, 3.5 Hz, 2H), 7.24 (br s, 1H), 6.86 (d, J
= 8.6 Hz, 1H), 6.76 (br s, 2H); 13C NMR (100 MHz, DMSO-d6):
δ 171.8, 150.2, 139.5, 137.4, 136.6, 136.2, 135.7, 130.9, 127.6,
127.4, 126.5, 125.6, 125.1, 123.6, 122.7, 119.1, 117.6, 114.4;
HRMS-ESI: Calcd. for C19H12NOS [M-NH2]+ m/z: 302.0634;
Found 302.0556.
2.3.8. 3',4-Diamino-[1,1'-biphenyl]-3-carboxamide (4h): Brown
powder:37 mg, 87% yield; Rf (40% EtOAc-Hexane): 0.46,
MP:144-148 οC; FTIR (KBr) νmax: 3381, 3289, 3174, 2923, 2856,
1635, 1574, 1484, 1406, 1304, 1246, 1163, 828, 782, 694,
1
651cm-1; H NMR (400 MHz, DMSO-d6) δ 7.91 (br s, 1H), 7.75
(d, J = 2.1 Hz, 1H), 7.37 (dd, J = 8.5, 2.1 Hz, 1H), 7.08 (br s,
1H), 7.03 (t, J = 7.9 Hz, 1H), 6.79– 6.75(m, 2H), 6.74 (d, J = 8.5
Hz, 1H), 6.58 (br s, 1H), 6.48 – 6.45 (m, 1H), 5.01 (br s, 2H); 13C
NMR (100 MHz, DMSO-d6): δ 171.9, 149.8, 149.3, 141.3, 130.5,
129.6, 127.9, 127.1, 117.2, 114.5, 114.3, 112.5, 111.9; HRMS-
ESI: Calcd. for C13H13N3O [M+H]+ m/z: 228.1137; Found
228.1138 and Calcd. for C13H11N2O [M-NH2]+ m/z: 211.0871;
Found 211.0868.
2.3.3. 2-Amino-5-(1H-indol-6-yl)benzamide (4c): Brown semi
solid: 40 mg, 85% yield; Rf (40% EtOAc-Hexane): 0.48; FTIR
1
(KBr) νmax: 3434, 2352, 2266, 1643, 1018, 821, 766 cm-1; H
NMR (400 MHz, DMSO-d6) δ 11.04 (s, 1H), 7.98 (s, 1H), 7.85
(d, J = 2.2 Hz, 1H), 7.59 – 7.54 (m, 2H), 7.49 (dd, J = 8.5, 2.2
Hz, 1H), 7.32 – 7.29 (m, 2H), 7.11 (s, 1H), 6.78 (d, J = 8.5 Hz,
1H), 6.58 (s, 2H), 6.41 (ddd, J = 2.9, 1.9, 0.8 Hz, 1H); 13C NMR
(100 MHz, DMSO-d6): δ 171.9, 149.3, 137.1, 134.0, 130.8,
128.7, 127.2, 126.7, 125.9, 120.6, 118.4, 117.5, 114.7, 108.7,
101.3. HRMS-ESI: Calcd. for C15H11N2O [M-NH2]+ m/z:
235.0866; Found 235.0864.
2.3.9. 2',4-Diamino-[1,1'-biphenyl]-3-carboxamide (4i): Brown
powder: 33 mg, 75% yield; Rf (40% EtOAc-Hexane): 0.47,
MP:152-157 οC; FTIR (KBr) νmax: 3433, 3395, 3312, 3138, 2923,
1628, 1539, 1492, 1453, 1404, 1285, 1250, 1156, 904, 815, 747,
1
647, 569, 495, 447 cm-1; H NMR (400 MHz, DMSO-d6) δ 7.79
(br s, 1H), 7.54 (d, J = 2.0 Hz, 1H), 7.19 (dd, J = 8.4, 2.0 Hz,
1H), 7.03 (br s, 1H), 7.00 – 6.96 (m, 2H), 6.75 (d, J = 8.4 Hz,
1H), 6.71 (dd, J = 8.5, 1.2 Hz, 1H), 6.60 (td, J = 7.4, 1.2 Hz, 1H),
6.53 (br s, 2H), 4.68 (br s, 2H); 13C NMR (100 MHz, DMSO-d6):
δ 171.8, 149.3, 145.5, 132.7, 130.5, 129.2, 127.8, 126.4, 126.3,
117.1, 115.4, 114.8; HRMS-ESI: Calcd. for C13H13N3NaO
[M+Na]+ m/z: 250.0956; Found 250.0954 and Calcd. for
C13H11N2O [M-NH2]+ m/z: 211.0871; Found 211.0870.
2.3.4. 2-Amino-5-(pyren-1-yl)benzamide (4d): Dark brown
powder: 51 mg, 80% yield; Rf (40% EtOAc-Hexane): 0.51,
ο
1
MP:197-201 C; H NMR (400 MHz, DMSO-d6) δ 8.38 – 8.28
(m, 3H), 8.26 – 8.17 (m, 4H), 8.13 – 8.07 (m, 2H), 7.93 (br s,
1H), 7.90 (s, 1H), 7.49 (dd, J = 8.4, 1.9 Hz, 1H), 7.17 (br s, 1H),
6.98 (d, J = 8.4 Hz, 1H), 6.86 (br s, 2H); 13C NMR (100 MHz,
DMSO-d6): δ 171.7, 150.1, 137.9, 134.4 131.5, 131.0, 130.0,
128.3, 128.2, 128.0, 127.8, 127.4, 126.8, 125.5, 125.4, 125.2,
125.1, 124.8, 124.7, 117.0, 114.5; HRMS-ESI: Calcd. for
C23H14NO [M-NH2]+ m/z: 320.1070; Found 320.1083.
2.3.10. 4-Amino-4'-cyano-[1,1'-biphenyl]-3-carboxamide (4j):
Brown powder: 43 mg, 95% yield; Rf (30% EtOAc-Hexane):
ο
0.52, MP:147-151 C; FTIR (KBr) νmax: 3478, 3440, 3404, 3179,
2772, 2224, 1917, 1682, 1656, 1575, 1560, 1485, 1402,
1
13331276, 1172, 1096, 1014, 950, 901, 883, 819,763 cm–1; H
2.3.5. 2-Amino-5-(naphthalen-1-yl)benzamide (4e): Brown
powder: 41 mg, 82% yield; Rf (40% EtOAc-Hexane): 0.49,
MP:148-152 οC; FTIR (KBr) νmax: 3343, 3047, 2923, 1653, 1388,
NMR (400 MHz, DMSO-d6) δ 8.02 (br s, 1H), 7.99 (d, J = 1.9
Hz, 1H), 7.86 (td, J = 8.6, 6.6 Hz, 4H), 7.62 (dd, J = 8.7, 2.2 Hz,
1H), 7.20 (br s, 1H), 6.94 (br s, 2H), 6.81 (d, J = 8.6 Hz, 1H); 13
C
1
1259, 1160, 781, 580 cm-1; H NMR (400 MHz, CDCl3) δ 7.81
NMR (100 MHz, DMSO-d6): δ 171.5, 151.3, 145.0, 133.1, 130.8,
(dd, J = 8.3, 1.2 Hz, 2H), 7.75 (dd, J = 8.3, 0.8 Hz, 1H), 7.43 –

128.0, 126.4, 124.3, 119.7, 117.6, 114.2, 108.5; HRMS-ESI:
Calcd. for C14H11N3O [M+H]+ m/z: 238.0980; Found 238.0975
and Calcd. for C14H9N2O [M-NH2]+ m/z: 221.0715; Found
221.0711.
2H), 5.67 (BR s, 2H); 13C NMR (100 MHz, CDCl3): δ 171.5,
148.9, 138.9, 132.6, 131.6, 128.9, 128.3, 127.5, 126.4, 118.0,
114.7, 114.3; HRMS-ESI: Calcd. for C13H11ClN2O [M+2]+ m/z:
248.0360; Found 248.0391 and Calcd. for C13H9ClNO [M-NH2]+
m/z: 230.0373; Found 230.0278.
2.3.11. 4-Amino-4'-methoxy-[1,1'-biphenyl]-3-carboxamide (4k):
Brownish semisolid: 41 mg, 90% yield; Rf (40% EtOAc-
Hexane): 0.50; FTIR (KBr) νmax: 3479, 3433, 3376, 3190, 2923,
2854, 1641, 1568, 1490, 1401, 1301, 1260, 1162, 1093, 900, 878,
808, 761, 715 cm–1; 1H NMR (400 MHz, DMSO-d6) δ 7.95 (br s,
1H), 7.83 (d, J = 2.2 Hz, 1H), 7.54 (d, J = 8.2 Hz, 2H), 7.47 (dd,
J = 8.6, 2.2 Hz, 1H), 7.20 (d, J = 7.9 Hz, 2H), 7.11 (br s, 1H),
6.76 (d, J = 8.5 Hz, 1H), 6.66 (s, 2H), 2.32 (s, 3H); 13C NMR
(100 MHz, DMSO-d6): δ 171.6, 149.8, 137.7, 135.5, 130.4,
129.7, 126.9, 125.9, 117.4, 114.5, 21.1.
2.3.17. 4'-Amino-[1,1':3',1''-terphenyl]-5'-carboxamide (5a):
Brown powder: 31 mg, 83% yield; Rf (40% EtOAc-Hexane):
ο
0.48, MP:201-205 C; FTIR (KBr) νmax: 3421, 3350, 3182, 2922,
2856, 1636, 1582, 1458, 1405, 1312, 1252, 1131, 889, 809, 753,
1
694, 642, 584, 497 cm-1; H NMR (400 MHz, DMSO-d6) δ 8.11
(br s, 1H), 7.91 (d, J = 2.2 Hz, 1H), 7.70– 7.68 (m, 2H), 7.52 –
7.46 (m, 4H), 7.42 – 7.38 (m, 4H), 7.31 (s, 1H), 7.26 (t, J = 7.3
Hz, 1H), 6.31(br s, 2H); 13C NMR (100 MHz, DMSO-d6): δ
172.0, 146.4, 140.3, 139.2, 131.6, 129.5, 129.4, 129.2, 129.0,
127.9, 127.3, 127.0, 126.7, 126.3, 115.8; HRMS-ESI: Calcd. for
C19H16N2O [M+H]+ m/z: 289.1341; Found 289.1348 and Calcd.
for C19H14NO [M-NH2]+ m/z: 272.1075; Found 272.1066.
2.3.12. 4-Amino-2'-methyl-[1,1'-biphenyl]-3-carboxamide (4l):
Brown powder: 36 mg, 84% yield; Rf (40% EtOAc-Hexane):
ο
0.51, MP:142-146 C; FTIR (KBr) νmax: 3426, 3334, 3195, 2922,
2857, 1667, 1622, 1482, 1396, 1312, 1261, 1161, 915, 837, 754,
658, 603 cm–1; 1H NMR (400 MHz, CDCl3) δ 7.23 (d, J = 2.0 Hz,
1H), 7.18 – 7.16 (m, 2H), 7.16 – 7.010(m, 3H), 6.65 (d, J = 8.4
Hz, 1H), 5.78 (br s, 2H), 5.65 (br s, 2H), 2.20 (s, 3H); 13C NMR
(100 MHz, CDCl3): δ 171.7, 148.3, 141.0, 135.5, 133.9, 130.4,
130.2, 129.8, 128.6, 127.1, 125.9, 117.2, 113.7, 20.5; HRMS-
ESI: Calcd. for C14H14N2O [M+H]+ m/z: 227.1184; Found
227.1205 and Calcd. for C14H12NO [M-NH2]+ m/z: 210.0919;
Found 210.0933.
2.3.18.4'-Cyano-4-(phenylamino)-[1,1'-biphenyl]-3-carboxamide
(10a): Colourless crystal : 46 mg, 70% yield; Rf (30% EtOAc-
Hexane): 0.51; FTIR (KBr) νmax: 3430, 3206, 2923, 2228, 1667,
1629, 1594, 1495, 1392, 1286, 1238, 998, 824, 743, 700, 546 cm-
1
;
1H NMR (400 MHz, DMSO-d6) δ 10.28 (s, 1H), 8.33 (br s,
1H), 8.13 (d, J = 2.2 Hz, 1H), 7.94 – 7.87 (m, 4H), 7.75 (dd, J =
8.8, 2.2 Hz, 1H), 7.59 (br s, 1H), 7.35 (ddd, J = 10.5, 6.3, 2.5 Hz,
3H), 7.23 – 7.21 (m, 2H), 7.05 (dd, J = 10.5, 4.2 Hz, 1H); 13C
NMR (100 MHz, DMSO-d6): δ 171.6, 146.3, 144.3, 141.1, 133.2,
131.1, 130.0, 128.5, 127.3, 127.0, 123.2, 121.2, 119.6, 117.5,
115.1, 109.3; HRMS-ESI: Calcd. for C20H15N3O [M+H]+ m/z:
314.1215; Found 314.1280.
2.3.13. 4-Amino-4'-methyl-[1,1'-biphenyl]-3-carboxamide (4m):
Brown powder: 37 mg, 87% yield; Rf (40% EtOAc-Hexane):
ο
0.51, MP:167-171 C; FTIR (KBr) νmax: 3479, 3388, 3287, 3177,
2923, 2854, 1649, 1617, 1487, 1460, 1395, 1302, 1256, 1165,
1110, 904, 814, 725 cm-1; 1H NMR (400 MHz, CDCl3) δ 7.48 (d,
J = 2.1 Hz, 1H), 7.40 (dd, J = 8.5, 2.1 Hz, 1H), 7.34 – 7.31 (m,
2H), 7.14 (d, J = 7.9 Hz, 2H), 6.68 (d, J = 8.5 Hz, 1H), 5.63 (br s,
4H), 2.30 (s, 3H); 13C NMR (100 MHz, CDCl3): δ 171.6, 148.5,
137.6, 136.4, 131.7, 129.7, 129.5, 126.3, 126.2, 117.9, 114.3,
21.1. HRMS-ESI: Calcd. for C14H14N2NaO [M+Na]+ m/z:
249.1004; Found 249.1005 and Calcd. for C14H12NO [M-NH2]+
m/z: 210.0919; Found 210.0920.
2.3.19. 4'-Cyano-4-(p-tolylamino)-[1,1'-biphenyl]-3-carboxamide
(10b): Brown powder: 44 mg, 65% yield; Rf (40% EtOAc-
ο
Hexane): 0.52, MP:208-212 C; FTIR (KBr) νmax: 3445, 3206,
2222, 1656, 1595, 1504, 1392, 1325, 1285, 1237, 808, 651, 498
1
cm-1; H NMR (400 MHz, DMSO) δ 10.20 (s, 1H), 8.32 (br s,
1H), 8.12 (d, J = 2.0 Hz, 1H), 7.89 (dd, J = 19.4, 8.2 Hz, 4H),
7.71 (d, J = 8.8 Hz, 1H), 7.56 (br s, 1H), 7.23 (d, J = 8.8 Hz, 1H),
7.14 (dd, J = 23.5, 8.2 Hz, 4H), 2.28 (s, 3H); 13C NMR (100
MHz, DMSO): δ 171.1, 147.0, 144.4, 138.3, 133.2, 132.7, 131.2,
130.5, 128.4, 126.8, 126.7, 122.0, 119.6, 116.8, 114.7, 109.1,
20.9; HRMS-ESI: Calcd. for C21H17N3O [M+H]+ m/z: 328.1372;
Found 328.1427.
2.3.14. 4-Amino-[1,1'-biphenyl]-3-carboxamide (4n): Brown
powder: 36 mg, 90% yield; Rf (40% EtOAc-Hexane): 0.52,
MP:144-148 οC; FTIR (KBr) νmax: 3675, 3383, 3305, 3183, 2922,
2856, 1737, 1641, 1572, 1482, 1402, 1255, 1161, 831, 757, 651
cm-1; 1H NMR (400 MHz, DMSO-d6) δ 7.97 (br s, 1H), 7.86 (d, J
= 2.2 Hz, 1H), 7.65 (dd, J = 8.3, 1.1 Hz, 2H), 7.50 (dd, J = 8.6,
2.2 Hz, 1H), 7.432– 7.38 (m, 2H), 7.26 – 7.23 (m, 1H), 7.13 ( br
s, 1H), 6.78 (d, J = 8.5 Hz, 1H), 6.68 (br s, 2H); 13C NMR (100
MHz, DMSO-d6): δ 171.7, 150.1, 140.5, 130.6, 129.1, 127.3,
126.8, 126.4, 126.1, 117.4, 114.4.
2.3.20.
4'-Cyano-4-(naphthalen-1-ylamino)-[1,1'-biphenyl]-3-
carboxamide (10c): Brown powder: 49 mg, 65% yield; Rf (30%
ο
EtOAc-Hexane): 0.51, MP:242-245 C; FTIR (KBr) νmax: 3424,
1
3173, 2225, 1590, 1527, 1403, 1287, 545 cm-1; H NMR (400
MHz, DMSO-d6) δ 10.86 (s, 1H), 8.45 (br s, 1H), 8.21 (d, J = 2.0
Hz, 1H), 8.01 – 7.96 (m, 2H), 7.90 (dd, J = 19.4, 8.5 Hz, 4H),
7.71 (ddd, J = 10.7, 7.4, 2.5 Hz, 3H), 7.58 – 7.52 (m, 4H), 7.11
(d, J = 8.8 Hz, 1H); 13C NMR (100 MHz, DMSO-d6): δ 171.9,
147.8, 143.4, 136.8, 134.9, 133.2, 131.3, 129.0, 128.6, 128.5,
127.1, 126.9, 126.8, 126.6, 124.5, 122.2, 119.6, 118.9, 116.8,
115.1, 109.2; HRMS-ESI: Calcd. for C24H17N3O [M+H]+ m/z:
364.1372; Found 364.1426.
2.3.15. 4-Amino-4'-fluoro-[1,1'-biphenyl]-3-carboxamide (4o):
Brown powder: 33 mg, 76% yield; Rf (40% EtOAc-Hexane):
ο
0.50, MP:146-150 C; FTIR (KBr) νmax: 3410, 3205, 1672, 1622,
1
1562, 1491, 1402, 1229, 1159, 1096, 819, 633 cm-1; H NMR
(400 MHz, CDCl3) δ 7.45 (d, J = 2.1 Hz, 1H), 7.39 – 7.34 (m,
3H), 7.04– 6.99 (m, 2H), 6.69 (d, J = 8.5 Hz, 1H), 5.85 (br s,
4H); 13C NMR (100 MHz, CDCl3): δ 171.6, 163.2, 148.6, 131.7,
128.8, 127.9, 127.8, 126.4, 118.0, 115.7, 115.5; HRMS-ESI:
Calcd. for C13H9FNO [M-NH2]+ m/z: 214.0663; Found 214.0674.
2.3.21.4-(4'-Oxo-3',4'-dihydro-1'H-spiro[fluorene-9,2'-
quinazolin]-6'-yl)benzonitrile (12a): Yellow semisolid: 67 mg,
80% yield; Rf (30% EtOAc-Hexane): 0.51; FTIR (KBr) νmax
:
3435, 3284, 3044, 2921, 2230, 1648, 1607, 1495, 1328, 1286,
1168, 1019, 818, 729, 656, 539 cm-1; 1H NMR (400 MHz,
DMSO-d6) δ 8.64 (d, J = 1.4 Hz, 1H), 8.14 (d, J = 2.3 Hz, 1H),
7.88 (s, 4H), 7.81 (d, J = 7.5 Hz, 2H), 7.75 (dd, J = 8.5, 2.4 Hz,
1H), 7.65 (d, J = 1.2 Hz, 1H), 7.54 (d, J = 7.4 Hz, 2H), 7.45 (td, J
= 7.5, 1.1 Hz, 2H), 7.30 (td, J = 7.5, 1.0 Hz, 2H), 6.82 (d, J = 8.5
Hz, 1H); 13C NMR (100 MHz, DMSO-d6): δ 163.9, 148.7, 148.2,
144.7, 138.5, 133.3, 132.5, 130.5, 129.0, 127.2, 126.7, 126.0,
2.3.16. 4-Amino-4'-chloro-[1,1'-biphenyl]-3-carboxamide (4p):
Brown powder: 33 mg, 72% yield; Rf (40% EtOAc-Hexane):
ο
0.51, MP:167-171 C; FTIR (KBr) νmax: 3435, 3383, 3348, 3206,
2923, 2854, 1890, 1581, 1482, 1427, 1409, 1309, 1277, 1166,
1
1093, 1036, 1011, 901, 879, 815, 762, 720, 703 cm–1; H NMR
(400 MHz, CDCl3) δ 7.46 (d, J = 2.1 Hz, 1H), 7.36 – 7.33 (m,
3H), 7.29 – 7.27 (m, 2H), 6.68 (d, J = 8.5 Hz, 1H), 5.83 (br s,

124.2, 128.8, 119.6, 115.7, 114.6, 109.1, 77.4; HRMS-ESI:
Calcd. for C27H17N3O [M+H]+ m/z: 400.1372; Found 400.1429.
2.3.22. 6-(4-Methoxyphenyl)-2-(ferrocenyl)quinazolin-4(3H)-one
(12b): Brown powder: 54 mg, 65% yield; Rf (40% EtOAc-
ο
Hexane): 0.51, MP:197-201 C; FTIR (KBr) νma1x: 3409, 3066,
2924, 1615, 1533, 1479, 1124, 754, 617 cm-1; H NMR (400
MHz, CDCl3) δ 10.56 (br s, 1H), 8.45 (d, J = 2.1 Hz, 1H), 7.94
(dd, J = 8.5, 2.2 Hz, 1H), 7.71 (d, J = 8.5 Hz, 1H), 7.56 (d, J =
8.1 Hz, 2H), 7.24 (d, J = 7.9 Hz, 2H), 5.09 – 5.08 (m, 2H), 4.51 –
4.50 (m, 2H), 4.18 (s, 5H), 2.36 (s, 3H); 13C NMR (100 MHz,
CDCl3): δ 163.3, 154.6, 148.9, 138.9, 137.7, 136.9, 133.7, 129.8,
127.8, 127.0, 124.0, 120.7, 71.5, 70.1, 68.0, 21.2; HRMS-ESI:
Calcd. for C25H20FeN2O2 [M+H]+ m/z: 437.1952; Found
437.1936.
3. Results and discussion
Initially,
a
mixture of 1.0 equiv. of 2-amino-5-
iodobenzamide 2a [39] and 1.2 equiv. of dibenzo[b,d]furan-4-
ylboronic acid 3a and 5 mol% Pd(OAc)2, Na2CO3 as base in
toluene was MW irradiated (100 Watts) for 5 minutes. The
reaction
afforded
2-amino-5-(dibenzo[b,d]furan-4-yl)
benzamide 4a in 20% yield (Table 1, entry 1, see ESI).
In order to optimize the reaction conditions, parameters
such as MW power and irradiation time, base, solvent system,
and catalyst and catalyst loading were considered. The
reaction under conventional heating yielded desired product
4a in lower yield and longer reaction time implying that under
MW condition afforded optimum yield with shorter reaction
time. Hence, the condition shown in table 1, entry 19 was
found to be optimum (see Table 1, ESI).
Encouraged by the preliminary results, and to demonstrate
the scope and diversity of the reaction, iodoamino amides
2a-b and a variety of aryl and hetero aryl boronic acids 3a-r
were screened for the reaction (Fig. 2). Thus, under optimised
condition, reaction of amino amides 2a-b with aryl and hetero
aryl boronic acids afforded 2-amino-3-carboxamide 1,1'-biaryl
derivatives 4a-p and 4'-amino-[1,1':3',1''-terphenyl]-5'-
carboxamide 5a in very good to excellent yields, except
boronic acids 3q and 3r did not react with 2a due to steric
hindrance.
From the results shown in Table 1, it has been observed that
boronic acids with heteroaryl moiety afforded biaryls with higher
yields up to 85% (Table 1, entries 1-3). It should be noted that
versatile functional groups such as -NH2, -CN, -F, -Cl remain
unreactive and observed only selective Suzuki coupled products
(Table 1, entries 15 and 16) [40]. In line with literature [41], we
have observed the coupling reaction of 2a with aryl boronic acids
undergone only C-C bond forming Suzuki coupling reaction to
provide biaryl derivatives 4 and did not observe any self
Buchwald N-C cross coupling products, namely, diphenyl amino
amide derivative of 2a. A plausible mechanism for the formation
of biaryl derivative 4a is depicted in Scheme 1 of ESI.
In addition to spectroscopic characterizations such FTIR and
NMR analysis of the products, a notable α-cleavage of amides
(N-CO bond) resulting M-16 (i.e M-NH2) peak with the loss of
neutral amine is observed for all biaryl compounds and is evident
from HR-ESI-MS analysis [42].
Products
NH
S
O
O
NH2
NH2
NH2
NH2
NH2
O
NH2
NH2
O
NH2 O
NH2
NH2
O
NH2
NH2 O
4f
4a
4b
4c
4d
4e
O
CN
NH2
NH2
NH2
NH2
NH2
O
NH2
NH2
NH2
NH2
O
NH2
O
NH2
NH2
4l
O
NH2
O
NH2
O
4h
4i
4g
4j
4k
Cl
F
NH2
NH2
NH2
NH2
NH2
O
NH2
O
NH2
O
NH2
O
NH2 O
4p
NH2
4m
4n
5a
4o
Fig. 2 Screened iodoamino amides and aryl/hetero aryl
boronic acids and biaryl products
Table 1 Scope of the reactiona
Entry
Amino
amide
2a
Boronic acid
Biaryl
Product
4a
% yieldc
2
3
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
3a
3b
3c
3d
3e
3f
3g
3h
3i
3j
3k
3l
3m
3n
3o
3p
3q
3r
3n
85
78
85
80
82
77
82
87
75
95
90
84
87
90
76
72
-
2a
2a
2a
2a
2a
2a
2a
2a
2a
2a
2a
2a
2a
2a
2a
2a
2a
2b
4b
4c
4d
4e
4f
4g
4h
4i
4j
4k
4l
4m
4n
4o
4p
-
-
-
83
5ab
a All the reactions were carried out by reacting 1 equiv. of 2a and 1.2
equiv. of 3a ; b 2.2 equiv. of 3n was used; cIsolated yield.

Similarly, for the most of the 2-amino-3-carboxamide-1,1'-
biaryl compounds synthesized, we have observed M-16 (i.e M-
NH2) as a base peak. Further, the peculiar mass spectral behavior,
protonation during mass spectral analysis and elimination of
neutral molecules i.e amines from amides is studied extensively
[43-47] to substantiate our observations.
The availability of functional group diversity in the 1,1'-
biaryls products prompted us to examine their synthetic
utility. Thus, firstly N-arylation of amine through Chan-
Evans-Lam reaction was considered.
Scheme 3 Synthesis of spiro and cyclic quinazolinones
heterocyclic derivatives 12a-b from 4j, 11a /4k, 11b
3.1. Photophysical studies
The structural uniqueness of the biaryl compounds obtained
herein encouraged us to explore their photophysical
properties.
Based on structural perspective, compound 4d was selected
for the evaluation of photophysical properties. Thus, UV
absorption and emission of compound 4d were recorded in
MeOH and showed an absorption maxima at 351 nm and
emission maxima at 463 nm, respectively. To find out the
influence of polarity solvent effect for the compound 4d, a
solvatochromism study was undertaken. Solvents such as
hexane, toluene, THF, chloroform, acetonitrile, DMSO in the
increasing order of polarity were used for the study.
Scheme 2 Synthesis of 10a-c from 4j and 3n/3m/3e through
Chan-Evans-Lam coupling
Thus, the reaction between 4j and aryl boronic acid 3n in
CH3OH using Et3N as base and CuCl as catalyst afforded
4'-cyano-4-(phenylamino)-[1,1'-biphenyl]-3-carboxamide 10a
in 70% yield. Compound 10a was thoroughly characterized by
spectroscopic data including single-crystal XRD method (Fig.
3) [48]. Similarly, compounds 10b-c were synthesised from
biaryl 4j and aryl boronic acids 3m and 3e, respectively
(Scheme 2). A plausible mechanism for the formation of
compound 10a is depicted in Scheme 2 of ESI.
(a)
Fig. 3 ORTEP diagram of compound 10a (CCDC-1889388)
To further demonstrate the synthetic utility of 1,1'
biaryls, spiro and cyclic quinazolinones heterocyclic
derivatives were synthesised as shown in Scheme 3.
Therefore, 4-(4'-oxo-3',4'-dihydro-1'H-spiro [fluorene-9,2'-
quinazolin]-6'-yl)benzonitrile 12a was synthesised from the
reaction between biaryl 4j and 9H-fluoren-9-one 11a in 80%
yield using phosphotungstic acid(HPW) as catalyst and MW
irradiation condition. Similarly, 6-(4-methoxyphenyl)-2-
(ferrocen-2-yl) quinazolin-4(3H)one 12b was synthesised in
65% yield by the reaction of biaryl 4k with ferrocene-2-
carboxaldehyde 11b.
(b)
Fig. 4 Solvatochromism for the compound 4d recorded at
C = 10-4 M at 298 K; (a) Normalised absorption spectra; (b)
Normalised emission spectra.

Table 4 Absorption and emission maxima of compounds
10a-c 12a,b
Table 2 Absorption and Emission Maxima of compound 4d in
,
various polarity of solvents
Entry Compound Absorptiona Emission
Stokes
shift,
Quantum
Entry
Solvent
Absorptiona
Emissionb
yield
λmax, abs
(nm)
346
348
357
λmax, emi
(nm)
423
420
415
λmax, abs (nm)
λmax, emi (nm)
(cm-1)b
(5261)
(4926)
(3915)
(6941)
(6250)
c
(Φf)
1
2
3
4
5
6
7
8
Hexane
Toluene
THF
CHCl3
Dioxane
MeOH
CH3CN
DMSO
346
353
354
355
354
351
352
358
401
412
448
419
431
463
466
488
1
2
3
4
5
10a
10b
10c
12a
12b
0.0208
0.0035
0.0028
0.0904
0.0372
324
320
418
400
aRecorded in CH3CN at 298 K; Stokes shift = λmax, abs
-
λmax, emi (cm-1);
b
cDetermined with quinine sulfate as a standard (0.5 M H2SO4) Φf = 0.54
at excitation wavelength 366 nm.
a
Recorded at C = 10-4 M at 298 K; bExcited at the longest wavelength of
the absorption maxima
The results revealed that a red shift in the emission maxima
from 401 nm to 488 nm was observed as the polarity of the
solvent was increased and found highest emission wavelength
at 488 nm in DMSO (Table 2, Fig. 4). This may be due to the
electron rich pyrene system makes compound 4d more polar
in the excited state as polarity of solvent increased resulting in
the red shift [49].
Similarly, all the synthesized biaryl compounds were
evaluated for photophysical characteristics such as absorption
(λmax, abs), emission (λmax, emi), Stokes shift (∆υ) and quantum
yield (Φ). Figure 1 of ESI shows normalized absorption and
emission spectra of all the synthesized biaryls. The biaryl
compounds exhibited absorption maxima in the range of 230
to 370 nm, while emission maxima ranges from 405-466 nm.
Stokes shifts were calculated for all the compounds and the
amine substituted biaryl derivative 4i found to have highest
Stokes shift value 8784 cm-1 while the lowest Stokes shift
value 4248 cm-1 for compound 4c. The complete
photophysical data along with fluorescence quantum yield
(Φf) for the synthesized biaryls is summarized in Table 3.
Interestingly,4-amino-4'-cyano-[1,1'-biphenyl]-3-carboxamide
4j and 2-amino-5-(pyren-1-yl)benzamide 4d showed quantum
(a)
yields 0.844 and 0.514, respectively [50].
Terphenyl
derivatives 4g (0.336), 5a (0.291) and methyl substituted biaryl
derivatives 4l (0.327), 4m (0.237) showed relatively good
quantum yields.
Table 3 Photophysical properties of biaryl derivatives 4a-p
and 5a
Entry Product
Absorptiona Emission
Stokes
shift
Quantum
(b)
(a) Normalised absorption spectra of biaryl
yield
λmax, abs
(nm)
λmax, emi
(nm)
412
417
425
466
408
417
417
416
426
415
418
406
405
414
415
416
425
(cm-1)b
c
Fig.
5
(Φf)
derivatives 10a-c and 12a-b recorded in CH3CN at C = 10-4
M at 298 K; (b) Normalised emission spectra of biaryl
derivatives 10a-c and 12a-b recorded in CH3CN at C = 10-4
M at 298 K.
1
2
3
4
5
4a
4b
4c
4d
4e
4f
290, 321
278, 370
304, 360
280, 352
262, 307
278, 310
250, 311
285, 350
273, 310
230, 325
287, 350
273, 341
228, 348
290, 345
286, 348
296, 353
295, 355
6881
8278
4248
6950
8064
8278
8174
4533
8784
6673
4648
4695
4639
4831
4639
4290
4640
0.0874
0.0380
0.0541
0.5143
0.1971
0.0662
0.3362
0.1834
0.1590
0.8449
0.1579
0.3276
0.2378
0.1641
0.2333
0.1104
0.2916
Noteworthy, among all the synthesised blue emissive
biaryls 4a-p, and 5a, compounds 4d and 4j showed high
fluorescence quantum yield (Table 4) and thus could have a
significant application in materials for organic light-emitting
diode [51].
In conclusion, we have demonstrated a microwave assisted
synthesis of 2-amino-3-carboxamide 1,1'-biaryls derivatives
via Suzuki coupling reaction and the synthetic utility has been
demonstrated by the preparation of 4-(phenylamino)-[1,1'-
biphenyl]-3-carboxamides via Chan-Evans-Lam reaction and
4-(4'-oxo-3',4'-dihydro-1'H-spiro[fluorene-9,2'-quinazolin]-6'-
6
7
8
9
4g
4h
4i
10
11
12
13
14
15
16
17
4j
4k
4l
4m
4n
4o
4p
5a
aRecorded in CH3CN at 298 K; Stokes shift = λmax, abs
-
λmax, emi [cm-1];
b
cDetermined with quinine sulfate as a standard (0.5 M H2SO4) Φf = 0.54
yl)benzonitrile
(ferrocenyl)quinazolin-4(3H)-one via HPW
and
6-(4-methoxyphenyl)-2-
catalysed
at excitation wavelength 366 nm.
condensation reaction. All the compounds were evaluated for
photophysical properties and found luminescence in the blue
region.
In contrast, synthetically transformed biaryl derivatives
10a-c and 12a-b showed low quantum yields compared to
biaryls derivatives 4j and 4k (Table 4, Fig. 5).

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Chemistry; Elvers, B., Ed.; Wiley-VCH Verlag GmbH &
Co. KGaA: Weinheim, Germany, 2000.
Supporting Information
Copies of FTIR, 1H NMR, 13C NMR, DEPT-135, HRMS
spectra for all the new compounds and single crystal XRD data
for compound 10a are provided.
[13] Achten R, Koudijs A, Giesbers M. Marcelis AT,
Sudhölter EJ. Dimer biphenyl liquid crystals with
trisiloxane-containing spacers. Mol Cryst Liq Cryst
2007; 477: 169-176.
Conflicts of interest
There are no conflicts to declare.
Funding Information
[14] Mehravar E, Iturrospe A, Arbe A, Asua JM, Leiza JR.
Phase behaviour of side-chain liquid-crystalline polymers
containing biphenyl mesogens with different spacer
lengths synthesized via miniemulsion polymerization.
Polym Chem 2016; 7: 4736-4750.
[15] Kang NG, Changez M, Kim MJ, Lee JS. Effect of
biphenyl spacers on the anionic polymerization of 2-(4′-
vinylbiphenyl-4-yl)pyridine. Macromolecules 2014; 47:
6706-6714.
M. N. thanks UGC (New Delhi) for the award of RGNF. PS
thanks financial support from the DST (New Delhi) vide Grant
No. SB/EMEQ-044/2014.
Acknowledgements
P. S. thanks the Director, CSIR-CLRI and S. K. thanks the
Chancellor, VIT-Vellore for providing infrastructure facilities.
[16] McGlacken GP, Bateman LM. Recent advances in aryl-
aryl bond formation by direct arylation. Chem Soc Rev
2009; 38: 2447-2464.
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Highlights
•
•
•
Microwave assisted synthesis of blue emissive 2-amino-3-carboxamide 1, 1'-biaryls and
amino-terphenyl-carboxamide derivatives via Suzuki coupling.
Chemo selective synthesis of 4-(aryl amino)-[1, 1'-biphenyl]-3-carboxamide derivatives
via Chan-Evans-Lam coupling reaction.
HPW catalyzed synthesis of 4-(4'-oxo-3', 4'-dihydro-1'H-spiro[fluorene-9,2'-quinazolin]-
6'-yl)benzonitrile and 6-(4-methoxyphenyl)-2-(ferrocenyl) quinazolin-4(3H)-one under
solvent free microwave irradiation condition.
•
All the synthesized compounds have been evaluated for photophysical properties, showed
luminescence in the blue region with large Stokes shift and high quantum yields.

Declaration of interests
☒ The authors declare that they have no known competing financial interests or personal relationships
that could have appeared to influence the work reported in this paper.
☐The authors declare the following financial interests/personal relationships which may be considered
as potential competing interests: