Novel and efficient microwave-assisted three component reaction for the synthesis of oxazine derivatives

Article abstract of DOI:10.13005/ojc/320442

Oxazine derivatives can be prepared with yield upto 98% within a few minutes by an efficient and novel one pot microwave-assisted three-component reaction from 1-naphthol, various anilines and formalin using montmorillonite as the catalyst. The procedure is very simple, efficient and environmentally friendly as it does not use any toxic auxiliary or solvent. The key advantages of this process are high yields, shorter reaction times, and easy work-up and non-chromatographic method has been used for the purification of products.

Full text of DOI:10.13005/ojc/320442

ISSN: 0970-020 X
CODEN: OJCHEG
2016, Vol. 32, No. (4):
Pg. 2131-2138
ORIENTAL JOURNAL OF CHEMISTRY
An International Open Free Access, Peer Reviewed Research Journal
www.orientjchem.org
Novel and Efficient Microwave-Assisted Three Component
Reaction for the Synthesis of Oxazine Derivatives
PREETI BANSAL*, NAKUESHWAR DUTT JASUJA and GAJANAND SHARMA
Suresh Gyan Vihar University, Jagatpura, Jaipur-302033, India.
*Corresponding author E-mail: bpchemistry08@gmail.com
http://dx.doi.org/10.13005/ojc/320442
(Received: June 26, 2016; Accepted: July 29, 2016)
ABSTRACT
Oxazine derivatives can be prepared with yield upto 98% within a few minutes by an efficient
and novel one pot microwave- assisted three- component reaction from 1-naphthol, various anilines
and formalin using montmorillonite as the catalyst. The procedure is very simple, efficient and
environmentally friendly as it does not use any toxic auxiliary or solvent. The key advantages of
this process are high yields, shorter reaction times, and easy work-up and non – chromatographic
method has been used for the purification of products.
Keywords: Solvent free synthesis, multicomponent reaction, oxazine, microwave.
INTRODUCTION
inhibitors10 In chemistry (sustainable)11 the design
and development of sequence allowing highly
selective essence to determine molecular scaffolds
when structural diversity combined12 with eco-
compatibility13 that is great challenges for organic
chemists.in a single operation they build one product
from three or more reactant molecules with high
atom economy14 and multiple bond forming efficiency
of multiple bond forming15. It is their ability. to reach
this near ideal goal multicomponent reactions are
now well established approaches16. Solvent free
reactions are of almost interest from the ecological
point of view, and they often advantages, such as
reduced reaction time, increased product yields,
reduced environmental pollution, simple equipment
Heterocyclic skeletons serve as ideal
scaffold on which pharmacophore can be appended
to yield potent and special drugs1 .this is especially
true for heterocyclic compound (six member
ring), that possess a wide range of interesting
biological activities2 are core components of a
large number of substances. Oxazine derivatives
features prominently in many biologically important
natural products3 and other bioactive molecules4-7
the oxazine derivativeshave been used as the
basic framework for substance of interest in
numerous therapeutic areas such as antifungal8
, antibacterial, anti-candina albicans9 and kinase

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BANSAL et al., Orient. J. Chem., Vol. 32(4), 2131-2138 (2016)
(lab scale), increased selectivity and low cost microwave assisted were performed by using
TM
compared with reactions carried out in solvents. microwave synthesizer (CEM corp.) (a discover
As an alternative to organic solvents, chemists single mode cavity) producing continuous microwave
should employ other strategies to perform chemical irradiations at 2450 MHz’s. All experiment was
reactions, namely ionic liquid, supercritical fluids, conducted under argon. on TLC aluminium roll silica
water as solvent and solvent free conditions- like in gel 60 F254 (merk)TLC was performed .Melting points
presence of MW irradiation.This technique does not weredetermined on a kofler melting point apparatus
require solvents and considered “greener” method Melting points were determined. IR spectra were
then the conventional methods. The large scale taken on a spectrum one FT-IR spectrometer (Perkin
of applications of microwave chemistry has been Elmer). UV spectra were measured using a CARY
increased recently too many aspects of organic 4E spectrophotometer (Varian). NMR spectrawere
synthesis (17-21Microwave assisted synthesis are recorded on a Varian unity INOVA spectrometer (300/
1
a particularly attractive alternative to synthesis and 75 MHz ) in CDCl3; the H and C13 chemical shift
severalthermal conditions since they often proceed were referenced to residual solvent signals at äH
much faster and synthesis products with higher yields = 7.25and äC = 77.1 relative to Tetra methyl silane.
and higher purity.
Mass spectra were recorded on a MAT 90 with 70
ev ionization energy (finnigan MAT)
Although several methods for the
preparation of oxazine derivatives have been
reported previously22-25. Some have been focused
EXPERIMENT
on the multicomponent reactions method. This A Mixture of 1a (1.0 m mol), b (2.0 m mol) and c (1.0
method is advantageous over previous reports due m mol) were absorbed on Montmorillonite (76 mg)
to its short reaction time and solvent free conditions. with methanol and mixed thoroughly and irradiated
As per our interest26-28 to develop better protocol with Microwaves for a particular time till the reaction
for the synthesis of biologically active heterocyclic are completed., the mixture was allowed to cool to
compounds, we would like to report the synthesis r.t. After completion of the reaction. And washed
of
With EE or TBME (5X5 ml). In vacuo the combined
oxazine derivatives by the reaction of naphthol, organic extracts were concentrated And by column
formalin, and aniline in presence of MW irradiation. chromatography the residue was purified on silica
gel to yield (4a)
EXPERIMENTAL METHOD
Spectral data of compounds:-
from chemical companies Starting material were (4a) yield- 76%, mp.-62-63b , reaction time – 5 min,
purchased and used without purification. All Anal. Found: C, 82.65%; H, 5.83%; N, 5.48%, Calc.
Fig. 1: Microwave assisted three component synthesis of oxazine derivatives

BANSAL et al., Orient. J. Chem., Vol. 32(4), 2131-2138 (2016)
2133
C18H15NO: C, 82.73; H, 5.79; N, 5.36. IR (KBr,
ímax/cm-1):1032 (sym.C-O-C), 1213 (asym.C-O-C);
1H NMR (DMSO-d6, 4, 00 MHz, ä ppm):4.78 (s, 2H,
-Ar-CH2-N-), 5.42 (s, 2H, - O-CH2-N-), 6.81-7.55
(m, 11H, Ar-H); 13C NMR (DMSO-d6, 75 MHz,, ä
ppm): 49.2, 79.3, 112.6, 115.2, 117.4, 119.7, 120.6,
124.1, 125.3, 125.3, 126.1, 127.5, 129.1, 132.8,
147.8, 148.7
(4b) yield- 74%, mp. - 300(d), reaction time – 5 min,
Anal. Found: C, 78.45; H, 5.90; N, 4.72%, Calc.
C19H17NO2: C, 78.33; H, 5.88; N, 4.81. IR (KBr,
ímax/cm-1):1018(sym.C-O-C), 1227(asym.C-O-C);
1H NMR (DMSO-d6, 400 MHz, ä ppm): 3.61 (s,
3H, OMe), 4.88 (s, 2H, -Ar-CH2-N-), 5.41 (s, 2H,
-O-CH2-N-), 6.78-7.81 (m, 10H, Ar-H); 13C NMR
(DMSO-d6, 75MHz,, ä ppm):48.1, 52.1, 80.2, 111.1,
115.5, 117.3, 119.4, 121.2, 124.1, 125.6, 125.8,
126.7, 127.1, 130.2, 132.2, 146.7, 148.5
C-O-C); 1H NMR (DMSO-d6, 400 MHz, ä ppm):
4.51 (s, 2H, -Ar- CH2-N-), 5.52 (s, 2H, -O-CH2-N-),
6.85-7.91 (m, 8H, Ar-H); 13C NMR (DMSO-d6, 75
MHz,, ä ppm):50.1, 79.2, 106.4, 107.8, 119.4, 124.6,
125.3, 125.8, 126.3, 127.1, 132.5, 133.4, 134.8,
142.7, 147.1, 150.2
(4e) Yield- 70%, mp. – 196-198 c, reaction time – 5
min, Anal. Found: C: 82.71%, H: 6.30%, N: 5.04%.,
Calc.: C19H17NO, C: 82.88%; H: 6.22%; N: 5.09%;
IR (KBr, ímax/cm-1):1020 (sym.C-O-C), 1233 (asym.
C-O-C);1H NMR (DMSO-d6, 400 MHz, ä ppm):2.41
(s, 3H, CH3), 4.91 (s, 2H, -Ar- CH2-N-), 5.61 (s, 2H,
-O-CH2- -), 6.61-7.91 (m, 10H, Ar-H); 13C NMR
(DMSO-d6, 75 MHz,, ä ppm):21.1, 49.1, 78.7, 110.3,
115.1, 117.7, 119.5, 120.2, 124.4, 125.4, 125.8,
126.2, 127.3, 129.7, 132.2, 147.7, 148.1
(4f)Yield - 72%, mp. – 200(d), reaction time – 5 min,
Anal. Found: C: 78.48%, H: 6.37%, N: 4.67%., Calc:
C20H19NO2, C: 78.66%; H: 6.27%; N: 4.59%; IR
(KBr, ímax/cm-1): 1022 (sym.C-O-C), 1235 (asym.
C-O-C); 1H NMR (DMSO-d6, 400 MHz, ä ppm):
1.28 (t, 3H, J = 14 Hz, O-CH2-CH3), 3.97 (q, 2H,
J = 14 Hz ,O-CH2-CH3), 4.62 (s, 2H, -Ar-CH2-N-),
5.41 (s, 2H, -O-CH2-N- ), 6.18-7.45 (m, 10H, Ar-H);
13C NMR (DMSO-d6, 75 MHz,, ä ppm): 13.8, 48.7,
64.6, 81.4, 111.7, 114.6, 115.7, 117.4, 118.7, 121.1,
122.1, 124.4, 125.5, 125.6, 126.1, 127.5, 128.9,
133.1, 146.2, 149.2
(4c) Yield- 72%, mp. - 76-770 c, reaction time- 5
min, Anal. Found: C, 78.71; H, 6.28; N, 4.24, Calc.
C20H19NO2: C, 78.66; H, 6.72; N, 4.59. IR (KBr,
ímax/cm-1): 1027 (sym.C-O-C), 1223 (asym. C-O-
C);1H NMR (DMSO-d6, 400 MHz, ä ppm): 1.21 (t,
3H, J = 8 Hz, O-CH2-CH3), 3.91 (q, 2H, J = 8 Hz
,O-CH2-CH3), 4.91 (s, 2H, -Ar-CH2-N-), 5.41 (s, 2H,
-O-CH2-N-), 6.81-7.81 (m, 10H, Ar-H); 13C NMR
(DMSO-d6, 75 MHz,, ä ppm):14.5, 48.3, 65.2, 80.5,
112.5, 115.8, 117.3, 119.2, 120.2, 123.2, 124.7,
125.3, 125.5, 126.6, 127.8, 129.9, 132.1, 147.3
(4d) Yield- 76%, mp. – 72-74 c, reaction time – 5
min, Anal. Found: C, 43.58; H, 2.25; N, 2.64, Caic. :
C18H12Br3NO, C: 43.41%; H: 2.43%; N: 2.81%; IR
(KBr, ímax/cm-1):1015 (sym.C-O-C), 1225 (asym.
(4g)Yield - 74%, mp. – 118-120 c, reaction time – 5
min, Anal. Found.- C:77.87%, H:5.14%, N:5.15%.,
Calc. C18H14FNO, C: 77.40%; H: 5.05%; N: 5.01%;
IR (KBr, ímax/cm-1):1027 (sym.C-O-C), 1246 (asym.
Table 1: Reaction of various aniline with
1- naphthol and formalin (1: 1: 2 )
Entry Products M.F
R
Reaction time (min) Mp. (oc)
1
2
3
4
5
6
7
8
9
C18H15NO
C19H17NO2
C20H19NO2
C18H12Br3NO
C19H17NO
C20H19NO2
C18H14FNO
C19H17NO2
C19H17NO
H
5-10
5-10
5-10
5-10
5-10
5-10
5-10
5-10
5-10
62-63b
300(d)
76-77
4-OMe
4-OEt
2,4,6- tri Br
4- Me
2-OEt
4-F
3- OMe
2-Me
72-74
196-198
200(d)
118-120
280(d)
86-88

BANSAL et al., Orient. J. Chem., Vol. 32(4), 2131-2138 (2016)
2134
Table 2: Synthesis of oxazine derivatives
Entry
Reactant
Product
(1)
(2)
(3)
OH
OH
O
NH
1
H-NH2
HCHO
HCHO
HCHO
HCHO
HCHO
HCHO
2
3
4
5
6
O
N
OEt
OH
O
N
OEt
2
OH
Br
Br
O
N
Br
Br
2
3
OH
OH
O
N
CH
3
N H 2
OEt
O
N
OEt
2
OH
7
8
9
HCHO
HCHO
HCHO
O
N
F
OH
N H 2
O
N
OCH3
OCH3
2
OH
CH3
O
N
CH3

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BANSAL et al., Orient. J. Chem., Vol. 32(4), 2131-2138 (2016)
C-O-C);1H NMR (DMSO-d6, 400 MHz, ä ppm): (4i)Yield - 72%, mp.– 86-88 c, reaction time – 5 min,
4.91 (s, 2H, -Ar-CH2-N-), 5.61 (s, 2H, -O-CH2-N-), Anal. Found. – C:82.84%, H:6.68%, N:5.14%.,Calc
6.81-7.81 (m, 10H, Ar-H); 13C NMR (DMSO-d6, 75 C19H17NO, C: 82.88%; H: 6.22%; N: 5.09%; IR
MHz,, ä ppm):49.1, 78.6, 112.1, 115.6, 116.2, 117.3, (KBr, ímax/cm-1): 1028 (sym.C-O-C),1232 (asym.
118.1, 122.5, 123.2, 125.2, 125.7, 125.8, 127.6, C-O-C); 1H NMR (DMSO-d6, 400 MHz, ä ppm):
128.5, 130.5, 150.1
2.21(q, 3H, CH3), 4.91 (s, 2H, -Ar- CH2-N-), 5.71
(s, 2H, -O-CH2-N-), 6.81-7.91 (m, 10H, Ar-H); 13C
(4h)Yield - 72%, mp.– 280(d), reaction time – 5 min, NMR (DMSO-d6, 75 MHz,, ä ppm):20.1, 50.2, 79.2,
Anal. Found – C:78.21%, H:5.78%, N:4.90%., Calc 113.3, 116.2, 117.3, 119.1, 120.4, 124.6, 125.7,
C19H17NO2, C: 78.33 %; H: 5.88 %; N: 4.81 %; IR 126.0, 126.7, 127.8,129.6, 130.3, 147.1, 148.2,
(KBr, ímax/cm-1): 1028sym.C-O-C), 1212 (asym. 149.1, 150.3
C-O-C); 1H NMR (DMSO-d6, 400 MHz, ä ppm):
3.55 (s, 3H, OMe.), 4.71 (s, 2H, -Ar-CH2-N-), 5.51 Antibacterial screening
(s, 2H, -O-CH2-N-), 6.23-7.64 (m, 10H, Ar-H); 13C Prepare Muller Hinton agar medium and put into
NMR (DMSO-d6, 75MHz, ä ppm): 49.4, 53.7, 79.5, sterile Petriplates. On agar medium ,200ul of the
112.3, 114.6, 115.9, 117.4, 118.1, 120.8, 124.6, standard bacterial inoculums was spread by using
125.7, 125.8, 126.6, 127.6, 130.2, 133.2, 146.8, sterile cotton swab. In the inoculated agar medium
148.8, 151.2
the test impregnated discs were placed.To determine
Table 3: Antibacterial and Antifungal Activity of Compounds
(Newly Synthesized Oxazine Derivatives (1a-1i))
Antibacterial activity
Compound10µg/ml
S.aureus
B.subtillus
E.Coli
P. Aeruginosa
1(a)
1(b)
1(c)
1(d)
1(e)
1(f)
1(g)
1(h)
10
15
17
18
11
15
16
13
9
12
19
21
17
7
18
13
15
8
8
6
9
9
21
8
8
17
10
7
17
18
25
5
19
21
18
6
1(i)
ciprofloxacin
19
22
26
22
Antifungal activity
Compound 10µg/ml
C. Albicans A.niger Chrysosporium sp. Trichoderma sp.
1a
1b
1c
1d
9
17
18
10
7
8
15
17
12
9
7
14
19
13
8
6
13
16
14
6
1e
1f
1g
17
7
15
8
16
9
14
8
1h
1i
16
8
13
7
15
9
12
6
Clomatrimazole
19
18
20
18

BANSAL et al., Orient. J. Chem., Vol. 32(4), 2131-2138 (2016)
2136
Table 4: Antifungal activity of compounds
(newly synthesized oxazine derivatives (1a-1i))
Compound 10µg/ml C. Albicans
A.niger Chrysosporium sp. Trichoderma sp.
1a
1b
1c
1d
9
17
18
10
7
8
7
14
19
13
8
6
13
16
14
6
15
17
12
9
1e
1f
1g
17
7
15
8
16
9
14
8
1h
1i
16
8
13
7
15
9
12
6
Clomatrimazole
19
18
20
18
the sensitivity of each microbial species tested
Ciprofloxacin 10 ug/ml capacity discs were used
as positive references standard. For 24 hours all
petriplates were incubated at 37 c. Diameter of
inhibition was measured after incubation
compounds S. Aureus, Escherichia Coli, Bacillus
Subtillus and P. Aeruginosa were screened.
Ciprofloxacin were used as a standard at 100 ug/
ml. Compound 1a-1i were screened. S. Aureus for
compound 1d was found to be highly active on the
other hand for other compounds had low activity
with the ciprofloxacin. B. Subtillus shows highly
activity for compound 1c, on the other hand for other
compoundsshows low activity with the standard
ciprofloxacin. E. coli for compound 1d was found
to be highly active, on the other hand for other
compounds had low activity compared with the
standard ciprofloxacin. P. Aeruginosa for compound
1d was found to be highly active, on the other hand
for other compounds compound had low activity in
comparison the standard ciprofloxacin
o
Antifungal screening
Prepared a Sabouraud dextrose agar medium and
transferred into sterile petriplates. On agar medium
200 ul of the standardized fungal inoculums were
spread by using cotton swab. On the inoculated
agar medium the test impregnated discs were
placed.To determine sensitivity of each microbial
species tested Clomatrimazole 10 ug/ml was used
as positive references standard. For 24 hours all
petriplates were incubated at 37o c.diameter of zone
of inhibition was measured After the incubation
Antifungal screening
RESULT AND DISCUSSION
The fungal inhibition zone values (mm) are
given in table-4.The antifungal activity of compounds
C. Albicans, Aspergillus Niger, Chrysosporium sp.,
Trichoderma sp. Were screened. At a 100 µgmL-1
Clomatrimazole were used as a standard.Compound
1a-1i were screened. C. Albicans for compound 1b
and 1f was found to be Highly active, on the other
hand for compound 1a, 1c, 1d, 1e, 1g, 1h, 1i, had low
activity compared with standard Clomatrimazole.
Our results is present on the microwave
– assisted three component synthesis of oxazine
derivatives. When amounts of 1(a) aniline, 2(a) 1-
naphthol, 3(a) formalin were reacted in the presence
of montmorillonite in a sealed via under microwave
conditions.A focused single mode microwave reactor
for 5 min at 1400 c. has been used.Under these
conditions [1, 3] oxazine derivatives 4(a) could be
isolated app. In 76% yield.
Aspergillus Niger for compound 1c was
found to be highly active on the other hand for
compound 1a, 1b, 1d, 1e, 1f, 1g, 1h, 1i, had low
activity compared with standard Clomatrimazole.
Chrysosporium sp. For compound 1c was found
Antibacterial screening
The bacterial inhibition values (mm) are
shown in table-3. The antimicrobial activities of

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BANSAL et al., Orient. J. Chem., Vol. 32(4), 2131-2138 (2016)
to be highly active On the other hand for 1a, 1b, 1d, microwave assisted three component reactions with
1e, 1f, 1g, 1h, 1i show low activity with standard yield up to 76% within a few minutes.The method is
Clomatrimazole. Trichoderma sp. for compound 1c important due to high conversion, less reaction time,
was found to be highly active, On the other hand for and clean reaction profile, simple experimental and
1a, 1b, 1d, 1e, 1f, 1g, 1h, 1i show low activity with work-up procedure.
standard Clomatrimazole.
ACKNOWLEDGMENT
CONCLUSION
The author would like to thank the head,
we have designed an environmentally department of chemistry, Suresh gyan Vihar
friendly, green and efficient approach for the University, Jaipur (raj.) for the financial support. xz
synthesis of oxazine derivatives.By solvent free, the and providing necessary laboratory facilities.
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