Vinyl esters as effective acetaldehyde surrogates in [4 + 1] cycloaddition based multicomponent cascade

Article abstract of DOI:10.1039/c5ra10073a

A new multicomponent cascade has been designed by utilizing vinyl esters as effective acetaldehyde surrogate. While most of the cyclic α-ketoenols underwent a facile three component conversion to annulated furans, phenols such as naphthol and sesamol got

Full text of DOI:10.1039/c5ra10073a

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DOI: 10.1039/C5RA10073A
Vinyl esters as effective acetaldehyde surrogates in [4+1] cycloaddition based
multicomponent cascade
Manoj Kumar, Sourav Bagchi and Anuj Sharma*
Graphical abstract

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Vinyl esters as effective acetaldehyde surrogates in [4+1]
cycloaddition based multicomponent cascade
a
a
a,
Manoj Kumar , Sourav Bagchi and Anuj Sharma *
Received 00th January 20xx,
Accepted 00th January 20xx
A new multicomponent cascade has been designed by utilizing vinyl esters as effective acetaldehyde surrogate. While
most of the cyclic α-ketoenols underwent a facile three component conversion to annulated furans, phenols such as
naphthol and sesamol got simply acylated under the same reaction conditions. This microwave assisted method provides
clean access to a wide range of functionalised furans in a short span of time.
DOI: 10.1039/x0xx00000x
www.rsc.org/
y
r
t
s
i
Introduction
m
e
O
n
h
Having both “ester” and “olefinic” functionalities, the chemistry of
C
l
(Ref 1)
O
O
n
o
h
i
o
&
o
o
1
,2
O
t
lc
,
vinyl esters looks quite impressive. As an ester, it has been
utilized as an innocuous and mild acylating agent for several
important transformations and this indeed is the most explored
a
r
y
A
s
l
n
t
s
a
d
y
itio
nd
(
Ref 4)
c
ri
m
n
ly
D
A
A
P
c
ta
a
B
e
o
HO
C
S
O
C
C
,
OH
M
W
n
2
O N
1
N
O
area of its known chemistry (Figure 1). By contrast, there are only
Aldol Type
Condensation
O
Ba(OH)
2
N
O
few reports concerning its use as an activated olefinic input which
Aromatic &
Hetetrocyclic aldehyde
O
2
N
N
(
Ref 3a)
O
N
H
Markonikov addition
S
c(O
(Ref 2b)
have remained limited to Povarov and Markovnikov type additions
y
H
O
2
H N
r
Tf)
O
ist
a
le
N
O
fi
n
ic
2
Che
m
2
%
3
,
rt
(
Figure 1).
Che
H3
te
O
N
O
R
mist
ry
ola
CHO
n
E
R
sis
EtOOC
O
Interestingly, another very important yet scarcely explored use of
vinyl acetate is through its cleavage into an enolate and its
subsequent role in synthesis. In fact, nearly all it’s acylation
he
t
NH
syn
)
N
Povarov
addition
b
e
3
f
EtOOC
in
rid
e
(
Ref 2a)
(R
c
A
Figure 1 Reported functional Chemistry of vinyl acetate.
reactions are accompanied by simultaneous generation of this
1
We recently devised a general method for vinyl ester mediated
“
enolate half”. Except a couple of reports, the chemistry of this
transesterification of phenols under organocatalytic conditions
enolate functionality and ensuing aldehyde has remained largely
4
3
(
Figure 2, Scheme A). During this investigation, we found that this
unexplored (Figure 1).
otherwise very clean and successful reaction didn’t work well with
cyclic α-ketoenols and an unidentifiable mixture was obtained in all
the cases (Figure 2, Scheme B). We speculated that unlike phenols,
acylation was not privileged with cyclic enols and latent “enolate”
rather than “acyl component” might prefer to react with α-acidic
ketoenols. Hence, in this case, there were chances to use vinyl ester
as an acetaldehyde surrogate rather than an acylating agent. To test
this possibility and as a continuation to our previous work, we
herein present the first report of organocatalysed 4+1 cycloaddition
involving α-ketoenols, isocyanides and vinyl acetate as
acetaldehyde equivalent under microwave irradiation (Figure 2,
a
Department of Chemistry, Indian Institute of Technology Roorkee, Roorkee-
2
47667, India
Corresponding author
*
Phone: +9113 3228 4751
Fax: +9113 3227 3560
e-mail: anujsharma.mcl@gmail.com, anujsfcy@iitr.ac.in
Electronic Supplementary Information (ESI) available: [General Experimental detail,
1
13
Microwave Irradiation Experiment, General Procedure, H, C NMR and HRMS
Spectral Data and recorded Spectra]. See DOI: 10.1039/x0xx00000x
5
a-5e
Scheme C).
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Same conditions on phenols provided transesterification product enaminone 5a and some un-reacted starting material (Table 1,
7
without any intervention from the isocyanide component (Figure 2, entry 4). To our delight, this fluorescent compound turned out to
Scheme D).
be the desired furan 4a by spectroscopic analysis. The same
reaction worked even better at a higher temperature under
microwave conditions (Table 1, entry 5). Not only did the yield
improve under microwave irradiation, the compound got
crystallized in the reaction vial after cooling, which did not happen
under conventional heating. Replacing DABCO with other catalysts
like morpholine, piperidine, DBU, DMAP and DIPEA resulted in
lower yields of the product 4a (Table 1, entries 6-10). Some further
sets of experiments helped realize the fact that sub-stoichiometric
loading of DABCO upto 30% and a temperature of 120 °C under
microwave irradiation was better than other conditions (Table 1,
entries 11-16). While most of the other solvents were found
comparable or inferior to acetonitrile, use of isopropanol as solvent
further improved the yield of 4a (Table 1, entries 17-20). Finally, an
additional amount of vinyl acetate seemed to not only improve the
yield, but also suppress the competitive formation of enaminone 5a
Moreover, this work can be posed as an example of “Single
6
Reactant Replacement (SRR)” as suggested by Ganem.
(
Table 1, entries 13 and 21, 22). Hence the optimized condition for
the above reaction involved microwave heating of 4-
Hydroxycoumarin (1a, 1 mmol), vinyl acetate (2a, 1.5 mmol) and t-
butylisonitrile (3a, 1 mmol) at 120 °C for 10 minutes in isopropanol
using DABCO (30 mol %) as a catalyst.
Figure 2 Effect of Substrate on the reaction profile.
Results and discussion
To confirm the feasibility of the above three component
condensation, 4-Hydroxycoumarin (1a), vinyl acetate (2a) and t-
butylisonitrile (3a) were selected as model substrates and reacted
together. In preliminary investigation, all the three reactants were
resorted to either simple grinding without a solvent, stirring in
acetonitrile or heating at varied temperatures, unfortunately, all
these methods failed to provide the desired product 4a and mostly
the starting material was recovered (Table 1, entries 1-3) in addition
7
to formation of the respective enaminone 5a (formed via direct
addition of 1a and 3a) upon heating (Table 1, entry 3).
From these initial failures, it was obvious that a catalyst was
necessary to assist cleavage of the enol ester and subsequent
generation of the enolate. DABCO was picked up as a catalyst of
choice based on our recent experience of it being effective for the
cleavage of vinyl acetates.
Introduction of DABCO in catalytic amount (10 mol %) in
acetonitrile created a marked change in the reaction profile with
f
the formation of a fluorescent compound at a higher R alongside
2
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Table 1 Optimization of three component condensation.
HN
O
OH
O
O
Solvent, catalyst
Conditions
N
NC
3a)
Solvent
H
O
(2a)
O
1a)
O
O
(4a)
O
O
(5a)
O
(
(
b
Entry
Catalyst (mol %)
Conditions
Yield (%)
4
a
5a
1
2
3
4
Grinding (rt, 1 h)
Stirring (rt, 5h)
0
trace
trace
25
CH
CH
CH
CH
CH
CH
CH
CH
CH
CH
CH
CH
CH
CH
CH
3
CN
CN
CN
0
0
3
Heating (60 °C, 10h)
Heating (60 °C, 10h)
DABCO (10)
3
38
16
5
6
7
8
9
DABCO (10)
Morpholine
Piperidine
DBU
3
CN
CN
CN
CN
CN
CN
CN
CN
CN
CN
CN
CN
MW (120 °C, 10 min)
MW (120 °C, 10 min)
MW (120 °C, 10 min)
MW (120 °C, 10 min)
MW (120 °C, 10 min)
MW (120 °C, 10 min)
MW (120 °C, 10 min)
MW (120 °C, 10 min)
MW (120 °C, 10 min)
MW (160 °C, 10 min)
MW (120 °C, 5 min)
MW (120 °C, 20 min)
MW (120 °C, 10 min)
MW (120 °C, 10 min)
MW (120 °C, 10 min)
MW (120 °C, 10 min)
MW (120 °C, 10 min)
MW (120 °C, 10 min)
58
42
52
38
42
36
62
65
66
69
61
69
61
51
57
69
77
79
22
28
3
3
25
3
22
DMAP
3
25
1
1
1
1
1
1
1
1
1
1
2
0
1
2
3
4
5
6
7
8
9
0
DIPEA
3
28
DABCO (20)
DABCO (30)
DABCO (40)
DABCO (30)
DABCO (30)
DABCO (30)
DABCO (30)
DABCO (30)
DABCO (30)
DABCO (30)
DABCO (30)
DABCO (30)
3
18
3
14
3
10
3
22
3
21
3
26
1,4 Dioxane
Toluene
THF
12
28
21
IPA
10
c
2
1
IPA
trace
trace
d
2
2
IPA
h = hours, min = minutes, MW = Microwave conditions
DIPEA = N,N-Diisopropylethylamine, DMAP = 4-Dimethylaminopyridine, DBU = 1,8-Diazabicyclo[5.4.0]undec-7-ene, DABCO = 1,4-diazabicyclo[2.2.2]octane
THF = Tetrahydrofuran, IPA = 2-Propanol
a
General condition: 4-hydroxycoumarine 1a (1 mmol), vinyl acetate 2a (1 mmol), tert-butyl isocyanide 3a (1 mmol). Anton Paar Monowave 300 Microwave reactor,
Irradiation Power: 850 W, Ramp time: 1 min. 60 °C
b
c
d
Isolated yield; 1.5 mmol of vinyl acetate was used; 2.5 mmol of vinyl acetate was used.
Having achieved optimized conditions, we next decided to (Lawsone,
1c ),
4-hydroxy-6-methylpyrone
(1d),
2,5-
investigate the scope and limitations of the reaction (Table 2). A dihydroxycyclohexa-2,5-diene-1,4-dione (1e), 4-hydroxyquinolin-2-
number of C-H acids such as 4-hydroxycoumarins (1a), 1-hydroxy- (1H)-one (1f), 5,5-Dimethylcyclohexane-1,3-dione (Dimedone, 1g),
3H-benzo[f]chromen-3-ones (1b), 2-hydroxy-1,4-naphthoquinone cyclohexane-1,3-dione (1h) and vinyl esters (2a to 2d) and
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were taken which resulted in a diverse range of products (4a to 4s) isonitrile such as Benzylisonitrile (3e) and α-isocyano ester such as
as shown in Table 2. ethyl isocyanoacetate (3f) were also successfully tested.
The method seemed to be well tolerant to all the reactants. While Unfortunately, in the case of 5,5-Dimethylcyclohexane-1,3-dione
vinyl pivalate (2b), Vinyl benzoate (2c) were found comparable to (Dimedone, 1g) and cyclohexane-1,3-dione (1h), the reaction
vinyl acetate (2a), vinyl chloroacetate (2d) provided higher yield resulted in failures and each time a prospective product spot
probably because of higher electrophilicity of ester carbonyl.
degraded into an unidentifiable mixture before it was purified (4q
to 4s). There are reports of some electron-rich furans to be
sensitive towards atmospheric oxidation and it may have happened
Both cyclic and branched isonitriles such as tert-butylisonitrile (3a),
1
,1,3,3-tetramethylbutylisonitrile (3b) and cyclohexylisonitrile (3c)
8
in our case.
afforded the desired products in moderate to good yield. Aromatic
isonitrile such as 2,6-dimethylphenylisocyanide (3d), aralkyl
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a
Table 2 Scope of the reaction
Serial No.
1
C-H Acids
(a-h)
Vinyl Esters
2(a-d)
Isocyanides
3(a-f)
Products
4(a-s)
b
1
2
2
a
a
3a
3b
1
1
a
a
4
a (77%)
2
4
b (70%)
3
2
2
a
a
3c
1
a
4
c (67%)
4
NH
O
O
3
d
1
a
O
4
d (62%)
5
3
a
2
b
1
a
4
a (75%)
6
NH
O
2
c
3
d
1
a
O
O
4
d (73%)
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7
2
a
3a
1
b
4
e (69%)
8
2
a
3b
1
b
4
f (67%)
9
2a
2b
2b
3
c
1
b
4
g (69%)
1
0
3
a
1
b
4
e (67%)
1
1
1
b
3b
4
f (66%)
6
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1
2
2
2
a
3a
3b
1
1
c
c
4h (72%)
1
3
a
a
b
4
4
i (69%)
1
1
4
5
3
f
2
1
1
c
c
j (77%)
3
b
2
4
i (68%)
1
1
6
7
3
a
2
d
a
1
c
4h (85%)
2
3a
1
1
d
d
4
k (75%)
1
8
2
a
3b
4
l (69%)
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1
9
3
3
a
a
2
c
1
1
d
d
4
4
k (72%)
2
0
2
d
k (83%)
2
2
2
1
2
3
2
a
b
3a
1
1
e
e
4m (72%)
4m (74%)
2
3
a
2
a
3a
1
f
4
n (65%)
2
4
2
a
3
c
1
f
4
o (69%)
8
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2
5
NH
O
O
2
a
3e
1
f
N
H
4
p (62%)
2
6
2
2
a
a
3a
1
1
g
g
4
q (nd)
2
2
7
8
3
c
4
r (nd)
2
a
3a
1
h
4
s (nd)
a
General condition: C-H acid (1 mmol), vinyl ester (1.5 mmol), isocyanide (1 mmol), DABCO (30 mol%), IPA (2 ml) as a solvent. Anton PaarMonowave 300 Microwave
reactor, Irradiation Power: 850 W, Ramp time: 1 min. 60 °C, holding time: 10min. 120 °C.
b
Isolated yield. nd = not determined
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O
In order to examine the effectiveness of vinyl acetates as aldehyde
component, a comparative experiment was carried out using 4-
hydroxycoumarins (1a), acetaldehyde (2a’) and tert-butylisonitrile
OH
O
O
H
O
O
O
enone C
(1a)
3
CH COOH
[
4+1]
(
3a) under similar set of conditions. The respective product (4a) got
Cycloaddition
R1-NC = (3a),
Tautomerism
if R1 = tert-butyl
formed in relatively smaller amount (55 %) after column
purification. This result is in contrast to vinyl acetate, where direct
deposition of solid product was observed in reaction vial after
microwave heating (Figure 3). The result indicates the advantage of
vinyl ester over acetaldehyde for this particular transformation.
N
OH
N
R1
N
H
O
2
H O
O
O
Iminolactone D
TI
C
AL
C
Y
AT
CY
O
C
LE
Proton Shift
N
(
A)
N
H
N
N
(DABCO)
N
R1
O
O
(
B)
O
O
4a), if R1 = tert-butyl
O
(2a)
(
O
Figure 4 Proposed mechanism of vinyl acetate mediate three
component reaction.
We finally explored some other useful transformation to broaden
the utility and scope of this interesting chemistry (Figure 5). After
modulating several conditions, in two examples [multicomponent
synthesis of 1,8-dioxodecahydroacridines (6a and 6b) and bis(3-
hydroxycyclohex-2-enone) 7a], vinyl esters were found equally
effective. These results points to the fact that the usefulness of
vinyl esters as acetaldehyde surrogate is quite general in nature.
Figure 3 Difference in reaction outcome using acetaldehyde and
vinyl ester.
A plausible mechanism that is also consistent with the previous
3
b
literature is depicted in Figure 4. Initial nucleophilic attack from
DABCO leads to the cleavage of vinyl acetate to intermediate A and
enolate B. Hydrolysis of intermediate results in conversion of B into
enol and subsequently to corresponding aldehyde regenerating
DABCO in the process. Aldehyde, thus generated undergoes a
subsequent three component condensation to an iminolactone D,
by a well known [4+1] cycloaddition route. This N-substituted
iminolactone, by [1,3] proton shift yield the desired product.
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®
(
Spectrun Two). Melting points were performed with Ambassador
and Digital Melting point apparatus (Nutronics), Popular India. All
®
chemicals were purchased from sigma-Aldrich and used without
further purification.
Microwave Irradiation Experiment
All microwave experiments were carried out in a dedicated Anton
®
Paar Monowave 300 reactor , operating at a frequency of 2.455
GHz with continuous irradiation power of 0 to 300 W. The reactions
were performed in a G10 Borosilicate glass vial sealed with Teflon
septum and placed in a microwave cavity. Initially, microwave of
required power was used and temperature was being ramped from
room temperature to
a desired temperature. Once this
temperature was attained, the process vial was held at this
temperature for required time. The reactions were continuously
stirred. Temperature was measured by an IR sensor. After the
experiments a cooling jet cooled the reaction vessel to ambient
temperature.
Figure 5 Utilization of vinyl esters in other useful transformations.
Conclusions
General procedure for the microwave-assisted three component
reaction
In summary, a new multicomponent cascade has been devised,
which depends on enolate functionality arising from vinyl esters. 4-hydroxycoumarins 1a (1.0 mmol), vinyl acetate 2a (1.5 mmol),
The utility of this reaction was demonstrated by synthesizing a isonitrile 3a (1.0 mmol), DABCO (30 mol %) in isopropanol was
diverse array of functionalized furans. Additional benefits of this taken in G10 process vial capped with Teflon septum. After a pre-
microwave assisted method include, direct accumulation of pure stirring of 1 or 2 minutes, the vial was subjected to microwave
product, no need of laborious and time consuming columns, short irradiation with the initial ramp time of 1 minute at 70 °C. The
reaction time and preparative simplicity. The underlying chemistry temperature was then raised to 120 °C with the holding time of 10
looks impressive and may have potential applicability in number of minutes. The reaction mixture was cooled down to 0-5 °C by a
other useful transformations.
Experimental Section
General Experimental Detail
cooling air jet. The product got crystallized in the reaction vial,
which was then filtered off, in most of the cases, was pure enough
1
13
for spectral elucidation by H NMR, C NMR and HRMS.
2
-(tert-Butylamino)-3-methyl-4H- furo[3,2-c]chromen-4-one (4a).
NMR spectra were recorded on a Jeol Resonance ECX-400II.
Chemical shifts are reported in parts per million and are referenced
Yield: 77% (using vinyl acetate), 75% (using vinyl pivalate);
crystalline yellow solid; mp: 143-145 °C; IR (KBr) ν: 3311, 2975,
6
-
1 1
to TMS. Spectra were processed using MestReNova software. Mass
1
d
7
716, 1641, 1412, 1223, 980, 763 cm . H NMR (400 MHz, DMSO-
spectrometry (HRMS) was performed using a Bruker daltronics
6
): δ (ppm) 1.22 (s, 9H), 2.12 (s, 3H), 5.23 (s, 1H), 7.32-7.37 (m, 1H),
®
1
3
microTOF-QII spectrometer using ESI ionization, with less than 5
.39-7.45 (m, 1H), 7.45-7.52 (m, 1H), 7.65-7.80 (m, 1H). C NMR:
ppm error for all HRMS analyses. Analytical Thin layer
(
100 MHz, DMSO-
d
6
): δ (ppm) 8.3, 29.9, 53.3, 102.5, 110.8, 112.4,
®
chromatography (TLC) was performed on a silica gel plate (Merck
1
16.6, 119.8, 124.4, 129.3, 150.4, 151.2, 154.8, 157.7. HRMS (ESI)
+
60F254). IR spectra were done on Perkin Elmer FT-IR spectrometer
m/z calcd. for C16
H
17NO
3
[M+Na] : 294.1106, found: 294.1102.
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J. Name., 2013, 00, 1-3 | 11
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RSC Advances
Page 13 of 16
COMMUNICATION
-methyl-2-(2,4,4-trimethylpentan-2-ylamino)-4H-furo[3,2-
View Article Online
DOI: 10.1039/C5RA10073A
Journal Name
1
3
3
(d, 1H, J = 8.2 Hz). C NMR: (100 MHz, DMSO-d6): δ (ppm) 8.2, 29.9,
c]chromen-4-one (4b). Yield: 70% (using vinyl acetate); crystalline 53.7, 102.2, 106.6, 111.5, 117.2, 124.3, 126.0, 126.1, 128.3, 128.9,
yellow solid; mp: 178-180 °C; IR (KBr) ν: 3332, 2925, 1721, 1640, 130.0, 130.2, 150.7, 151.8, 154.9, 157.7. HRMS (ESI) m/z calcd. for
-
1
1
+
1
1
7
1
3
1
422, 1235, 992, 784 cm . H NMR (400 MHz, DMSO-d6): δ (ppm)
C
20 3
H19NO [M+Na] : 344.1263, found: 344.1259.
.08 (s, 9H), 1.26 (s, 2H), 1.42 (s, 6H), 2.02 (s, 3H), 5.23 (s, 1H), 7.19-
.27 (m, 2H), 7.31 (td, 1H,
J
= 6.0 & 1.1 Hz), 7.60 (dd, 1H,
.3 Hz). C NMR: (100 MHz, DMSO- ): δ (ppm) 10.6, 28.8, 31.6,
1.9, 54.0, 57.1, 85.5, 113.2, 114.8, 117.1, 124.4, 125.0, 132.8,
J = 5.9 &
3
-(4’-Methyl)-2-((2’’,4’’,4’’-trimethylpentan-2-yl)amino)-4H-
1
3
d
6
benzo[f]furo[3,2-c]chromen-4-one (4f). Yield: 67% (using vinyl
acetate), 66% (using vinyl pivalate); crystalline yellow solid; mp:
46.3, 152.6, 156.0, 161.8. HRMS (ESI) m/z calcd. for C20H25NO
3
1
1
1
28-130 °C; IR (KBr) ν: 3445, 2954, 1715, 1639, 1561, 1413, 1220,
+
[
M+Na] : 350.1732, found: 350.1724.
-1 1
009, 811 cm . H NMR (400 MHz, DMSO-
.33 (s, 6H), 1.74 (s, 2H), 2.18 (s, 3H), 5.34 (s, 1H), 7.53-7.63 (m, 2H),
= 8.4 Hz), 8.00 (d, 1H, = 9.0 Hz), 8.03 (d, 1H, = 7.9
= 8.4 Hz). C NMR: (100 MHz, DMSO-d6): δ (ppm)
47 °C; IR (KBr) ν: 3320, 2928, 2853, 1725, 1613, 1413, 1193, 1013, 8.2, 29.8, 31.4, 31.5, 54.0, 56.9, 100.1, 106.6, 111.7, 117.1, 124.3,
6
d ): δ (ppm) 1.06 (s, 9H),
2
-(cyclohexylamino)-3-methyl-4H-furo[3,2-c]chromen-4-one (4c). 7.69 (t, 1H,
J
J
J
1
3
Yield: 67% (using vinyl acetate); crystalline yellow solid; mp: 145- Hz), 8.90 (d, 1H,
J
1
8
1
1
7
-1 1
01, 751 cm . H NMR (400 MHz, DMSO-
d
6
): δ (ppm) 1.08-1.19 (m, 125.9, 126.0, 127.9, 128.8, 129.8, 130.0, 150.4, 151.0, 154.9, 157.7.
+
H), 1.21-1.35 (m, 4H), 1.52-1.63 (m, 1H), 1.69-1.77 (m, 2H), 1.85- HRMS (ESI) m/z calcd. for C24
.95 (m, 2H), 2.10 (s, 3H), 3.29-3.33 (m, 1H), 5.89 (d, 1H,
= 8.0 Hz), 400.1881.
.30-7.35 (m, 1H), 7.36-7.46 (m, 2H), 7.69 (d, 1H, = 7.8 Hz).
): δ (ppm) 7.3, 24.6, 25.3, 33.4, 53.5, 91.9,
12.1, 112.4, 116.4, 119.1, 124.5, 128.3, 148.0, 150.4, 155.5, 157.8.
H27NO
3
[M+Na] : 400.1889, found:
J
1
3
C
J
NMR: (100 MHz, DMSO-d
6
2
4
-(Cyclohexylamino)-3-(4’-methyl)-4H-benzo[f]furo[3,2-c]chromen-
1
-one (4g). Yield: 69% (using vinyl acetate); crystalline yellow solid;
+
HRMS (ESI) m/z calcd. for C H NO [M+Na] : 320.1263, found:
1
8
19
3
mp: 166-168 °C; IR (KBr) ν: 3442, 2930, 1708, 1637, 1558, 1413,
320.1255.
-1 1
1
1
232, 1018, 804 cm . H NMR (400 MHz, DMSO-d6): δ (ppm) 1.37-
.45 (m, 5H), 1.68-1.75 (m, 3H), 2.03 (s, 3H), 2.10-2.15 (m, 2H), 3.57
2-(2,6-dimethylphenylamino)-3-methyl-4H- furo[3,2-c]chromen-4- (quint, 1H, J = 5.9 Hz), 5.4 (s, 1H), 7.38-7.43 (m, 2H), 7.65-7.72 (m,
13
one (4d). Yield: 62% (using vinyl acetate), 73% (using vinyl 2H), 7.78-7.83 (m, 1H), 7.95-7.99 (m, 1H). C NMR: (100 MHz,
benzoate); crystalline yellow solid; mp: 195-196 °C; IR (KBr) ν: 3443, DMSO- ): δ (ppm) 10.6, 24.7, 25.9, 33.5, 51.3, 90.8, 105.6, 108.0,
d
6
-1 1
2
999, 1704, 1653, 1563, 1412, 1249, 1206, 807, 755 cm . H NMR 117.3, 123.7, 126.3, 126.7, 126.8, 130.4, 130.8, 131.3, 154.3, 154.6,
+
(
400 MHz, DMSO-d
6
): δ (ppm) 1.76 (s, 3H), 2.05 (s, 6H), 5.34 (s, 1H), 156.0, 156.4. HRMS (ESI) m/z calcd. for C22
H
21NO
3
[M+Na] :
6
7
.61 (t, 1H, J = 5.9 Hz), 6.76 (d, 2H, J = 5.9 Hz), 6.96-7.04 (m, 2H), 370.1419, found: 370.1411.
1
3
.19 (td, 1H, J = 6.0 & 1.2 Hz), 7.41 (dd, 1H, J = 6.0 & 1.2 Hz).
): δ (ppm) 10.6, 18.2, 95.0, 113.2, 114.8,
17.1, 124.4, 125.0, 126.6, 128.9, 132.8, 133.6, 140.9, 146.3, 152.6,
C
NMR: (100 MHz, DMSO-d
6
2
-(tert-butylamino)-3-methylnaptho[2,3-b]furan-4,9-dione
(4h).
1
1
3
Yield: 72% (using vinyl acetate), 85% (using vinyl chloroacetate);
+
56.0, 157.4. HRMS (ESI) m/z calcd. for C H NO [M+Na] :
20
17
3
crystalline purple solid; mp: 164-166 °C; IR (KBr) ν: 3433, 2972,
42.1106, found: 342.1101.
-1 1
1
671, 1641, 1563, 1413, 1268, 1207, 1017, 818, 720 cm . H NMR
400 MHz, DMSO- ): δ (ppm) 1.46 (s, 9H), 2.15 (s, 3H), 4.21 (s, 1H),
= 7.5 & 1.4 Hz), 7.66 (td, 1H, = 7.5 & 1.4 Hz), 8.04
= 7.8 & 1.4 Hz). C NMR:
): δ (ppm) 7.9, 30.2, 54.1, 126.2, 132.1, 132.2,
(
d
6
2-(tert-Butylamino)-3-(4’-methyl)-4H-benzo[f]furo[3,2-c]chromen-
7.58 (td, 1H,
J
J
13
4-one (4e). Yield: 69% (using vinyl acetate), 67% (using vinyl (dd, 1H, J = 7.5 & 1.3 Hz), 8.13 (dd, 1H, J
pivalate); crystalline yellow solid; mp: 208-210 °C; IR (KBr) ν: 3443, (100 MHz, CDCl
3
-1 1
2
963, 1716, 1563, 1413, 1222, 1018, 817 cm . H NMR (400 MHz, 133.1, 133.8, 133.9, 159.8, 168.8, 183.3. HRMS (ESI) m/z calcd. for
+
DMSO-
d
6
): δ (ppm) 1.31 (s, 9H), 2.20 (s, 3H), 5.40 (s, 1H), 7.58-7.66
C
17
H
17NO
3
[M+Na] : 306.1106, found: 306.1101.
(
m, 2H), 7.77 (t, 1H, = 7.1 Hz), 8.06 (dd, 2H, = 8.5 & 3.6 Hz), 8.92
J
J
1
2 | J. Name., 2012, 00, 1-3
This journal is © The Royal Society of Chemistry 20xx
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Please
R
d
S
o
C
no
A
t
d
a
v
d
a
ju
n
s
c
t
e
m
s
argins
Page 14 of 16
View Article Online
DOI: 10.1039/C5RA10073A
Journal Name
-methyl-2-(2,4,4-trimethylpentan-2-ylamino)naphtho[2,3-
COMMUNICATION
3
157.0, 157.1, 161.3, 161.5. HRMS (ESI) m/z calcd. for C H NO
17 25 3
+
b]furan-4,9-dione (4i). Yield: 69% (using vinyl acetate), 68% (using [M+Na] : 314.1732, found: 314.1728.
vinyl pivalate); crystalline purple solid; mp: 176-177 °C; IR (KBr) ν:
-
1 1
3
439, 2969, 1674, 1641, 1563, 1413, 1211, 1018, 781 cm . H NMR
400 MHz, DMSO- ): δ (ppm) 1.01 (s, 9H), 1.52 (s, 6H), 1.78 (s, 2H),
.14 (s, 3H), 4.32 (s, 1H), 7.57 (td, 1H, = 7.5 & 1.4 Hz), 7.66 (td, 1H,
= 7.5 & 1.4 Hz), 8.03 (dd, 1H, = 7.6 & 1.3 Hz), 8.13 (dd, 1H, = 7.5
1.3 Hz). C NMR: (100 MHz, CDCl ): δ (ppm) 7.7, 30.5, 31.6, 31.9,
2
,6-bis(tert-butylamino)-benzofuro[5,6-b]furan-4-8-diones (4m).
(
d
6
Yield: 72% (using vinyl acetate), 74% (using vinyl pivalate); black
2
J
J
solid; mp: >300 °C; IR (KBr) ν: 3438, 2969, 1698, 1639, 1567, 1412,
J
J
-1 1
1
207, 1020, 795 cm . H NMR (400 MHz, DMSO-
d
6
): δ (ppm) 1.43
1
3
&
13
3
(
(
s, 18H), 2.24 (s, 6H), 5.40 (s, 2H). C NMR: (100 MHz, DMSO-d ): δ
6
53.5, 57.7, 126.1, 131.9, 132.2, 133.0, 133.8, 134.0, 159.8, 168.4,
ppm) 4.5, 29.0, 52.9, 94.3, 119.2, 151.1, 153.1, 166.5. HRMS (ESI)
+
183.5. HRMS (ESI) m/z calcd. for C21
H
25NO
3
[M+Na] : 362.1732,
+
m/z calcd. for C20
H
26
N
2
O
4
[M+Na] : 381.1791, found: 381.1785.
found: 362.1726.
2
-(tert-butylamino)-3-methylfuro[3,2-c]quinolin-4-(5H)-one (4n).
Ethyl 2-(3-methyl-4,9-dioxo-4,9-dihydronaptho [2,3-b]furan-2-
ylamino)acetate (4j). Yield: 77% (using vinyl acetate); crystalline
purple solid; mp: 193-194 °C; IR (KBr) ν: 3311, 2978, 1719, 1648,
Yield: 65% (using vinyl acetate); yellow solid; mp: 145-147 °C; IR
-1
(
KBr) ν: 3437, 3311, 2975, 1715, 1641, 1412, 1223, 979, 763 cm .
1
H NMR (400 MHz, DMSO-
.72 (s, 1H), 7.17 (td, 1H, = 6.0 & 1.3 Hz), 7.25 (td, 1H,
= 6.0 & 1.1 Hz), 7.58 (dd, 1H, = 5.8 & 1.1 Hz),
d
6
): δ (ppm) 1.22 (s, 9H), 1.90 (s, 3H),
-
1 1
1
558, 1412, 1223, 1031, 894, 763 cm . H NMR (400 MHz, DMSO-
d6): δ (ppm) 1.39 (t, 3H, = 4.7 Hz), 2.09 (s, 3H), 4.24 (q, 2H, = 4.7
Hz), 4.32 (s, 1H), 4.75 (s, 1H), 7.73 (td, 1H, = 6.0 & 1.3 Hz), 7.77 (td,
= 5.8 & 1.4 Hz), 8.25 (dd, 1H,
.8 & 1.4 Hz), 9.51 (s, 1H). C NMR: (100 MHz, CDCl ): δ (ppm) 5.2,
5
J
J
= 5.9 & 1.1
J
J
Hz), 7.31 (dd, 1H,
J
J
J
13
9
5
1
2
.25 (s, 1H). C NMR: (100 MHz, DMSO-d6): δ (ppm) 10.6, 29.7,
1
5
1
1
3
H,
J
= 5.9 & 1.4 Hz), 8.22 (dd, 1H,
J
J =
3.6, 100.3, 110.7, 118.1, 119.1, 123.0, 123.7, 131.8, 137.1, 156.7,
13
+
3
57.0, 169.2. HRMS (ESI) m/z calcd. for C16
93.1266, found: 293.1260.
H
18
N
2
O
2
[M+Na] :
4.7, 46.1, 61.2, 86.3, 126.6, 132.2, 133.7, 136.0, 143.2, 159.3,
+
70.5, 174.9, 178.5. HRMS (ESI) m/z calcd. for C17
36.0848, found: 336.0842.
H15NO
5
[M+Na] :
2
-(cyclohexylamino)-3-methylfuro[3,2-c]quinolin-4-(5H)-one (4o).
Yield: 69% (using vinyl acetate); yellow solid; mp: 147-149 °C; IR
2-(tert-butylamino)-3-methyl-4H-furo[3,2-c]pyran-4-one (4k). Yield:
-1
(
KBr) ν: 3320, 2929, 2852, 1725, 1638, 1412, 1192, 1016, 751 cm .
7
5% (using vinyl acetate), 72% (using vinyl benzoate), 83% (using
1
H NMR (400 MHz, DMSO-d6): δ (ppm) 1.30-1.42 (m, 5H), 1.66-1.74
m, 3H), 1.89-1.99 (m, 2H), 2.13 (s, 3H), 3.43 (quint, 1H, = 5.8 Hz),
= 5.9 & 1.1
= 5.9 & 1.1 Hz),
vinyl chloroacetate); crystalline yellow solid; mp: 146-148 °C; IR
(
J
-1
(KBr) ν: 3310, 2976, 1712, 1642, 1553, 1412, 1223, 979, 763 cm .
5
.87 (s, 1H), 7.30 (td, 1H,
J
= 6.0 & 1.3 Hz), 7.38 (td, 1H,
J
1
H NMR (400 MHz, DMSO-d6): δ (ppm) 1.33 (s, 9H), 1.97 (s, 3H),
Hz), 7.45 (dd, 1H,
J
= 6.0 & 1.1 Hz), 7.73 (dd, 1H,
J
1
3
2
d
1
2
.18 (s, 3H), 4.33 (s, 1H), 5.98 (s, 1H). C NMR: (100 MHz, DMSO-
13
9
2
1
3
.22 (s, 1H). C NMR: (100 MHz, DMSO-d6): δ (ppm) 10.6, 24.7,
6
): δ (ppm) 8.23, 16.7, 27.3, 51.2, 76.9, 89.8, 104.9, 153.9, 154.0,
5.9, 33.5, 51.3, 102.2, 110.7, 118.1, 119.1, 123.0, 123.7, 131.8,
+
58.2, 158.3. HRMS (ESI) m/z calcd. for C12
44.0950, found: 244.0941.
H15NO
3
[M+Na] :
+
37.1, 156.7, 161.4. HRMS (ESI) m/z calcd. for C18
19.1423, found: 319.1418.
H
20
N
2
O
2
[M+Na] :
3,6-dimethyl-2-(2,4,4-trimethylpentan-2-ylamino)-4H-furo[3,2-
2
-(benzylamino)-3-methylfuro[3,2-c]quinolin-4-(5H)-one
(4p).
c]pyran-4-one (4l). Yield: 69% (using vinyl acetate); crystalline
yellow solid; mp: 178-180 °C; IR (KBr) ν: 3428, 2949, 1639, 1555,
Yield: 65% (using vinyl acetate); yellow solid; mp: 173-175 °C; IR
-1
(
KBr) ν: 3442, 3305, 2928, 2853, 1707, 1413, 1207, 1018, 840 cm .
-1 1
1
414, 1221, 1014, 925, 757 cm . H NMR (400 MHz, DMSO-
d
6
): δ
1
H NMR (400 MHz, DMSO-
d
6
): δ (ppm) 1.17 (s, 3H), 3.70 (d, 2H,
J =
(
ppm) 1.09 (s, 9H), 1.28 (s, 2H), 1.41 (s, 6H), 2.01 (s, 3H), 2.22 (s,
1
1
6
0.4 Hz), 4.86 (s, 1H), 6.15-6.20 (m, 1H), 6.21- 6.26 (m, 4H), 6.28 (td,
1
3
3
6
H), 5.40 (s, 1H), 6.04 (s, 1H). C NMR: (100 MHz, DMSO-d ): δ
H,
J
= 5.9 & 1.3 Hz), 6.36 (td, 1H,
J
= 5.9 & 1.3 Hz), 6.43 (dd, 1H, J =
(ppm) 11.3, 19.8, 29.6, 32.4, 32.7, 54.8, 57.8, 82.3, 92.9, 108.0,
13
.0 & 1.3 Hz), 6.70 (dd, 1H,
J
= 6.0 & 1.1 Hz), 8.65 (s, 1H). C NMR:
This journal is © The Royal Society of Chemistry 20xx
J. Name., 2013, 00, 1-3 | 13
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RSC Advances
Page 15 of 16
COMMUNICATION
View Article Online
DOI: 10.1039/C5RA10073A
Journal Name
1
3
(
100 MHz, DMSO-d6): δ (ppm) 10.6, 46.9, 97.3, 110.7, 118.1, 119.1, (q, 1H, J = 5.1 Hz), 13.12 (br s, 1H), 13.95 (br s, 1H). C NMR: (100
1
23.0, 123.7, 126.9, 128.4, 131.8, 137.1, 139.8, 156.7, 157.0, 157.9. MHz, DMSO-d
6
): δ (ppm) 24.7, 28.8, 33.2, 33.5, 45.0, 51.5, 116.9,
+
+
HRMS (ESI) m/z calcd. for C19
H
16
N
2
O
2
[M+Na] : 327.1110, found: 185.2, 192.7. HRMS (ESI) m/z calcd. for C18
H
26
O
4
[M+Na] :
327.1107.
329.1729, found: 329.1723.
3
2
2
-((tert-Butylamino)methylene)-3H-chromene-2,4-dione (5a). Yield:
Acknowledgements
5%; Yellow orange solid; mp: 182-184°C; IR (KBr) ν: 3449, 3240,
-
1 1
6
977, 1696, 1635, 1619, 1568 cm . H NMR (400 MHz, DMSO-d ): δ This work was financially supported by Department of Science and
(ppm) 1.33 (s, 9H), 7.21 (td, 1H, J = 6.0 & 1.3 Hz), 7.25 (dd, 1H, J = Technology (DST), New Delhi, Govt. of India (Grant No. SR/FT/CS-
6
1
5
.0 & 1.1 Hz), 7.48 (td, 1H, J = 6.0 & 1.1 Hz), 7.89 (dd, 1H, J = 6.0 & 55/2011). M. K. and S. B. would like to thank CSIR and MHRD for the
1
3
6
.1 Hz), 8.99 (s, 1H). C NMR: (100 MHz, DMSO-d ): δ (ppm) 28.8, award of research fellowship.
3.2, 101.5, 119.1, 123.8, 127.6, 136.2, 156.9, 161.6, 167.3, 176.2.
+
HRMS (ESI) m/z calcd. for C H NO [M+Na] : 268.0950, found:
1
4
15
3
Notes and references
268.0942.
3
,3,6,6,9-pentamethyl-3,4,6,7,9,10-hexahydroacridine-1,8-(2H,5H)-
1
(a) J. Otera, Chem. Rev., 1993, 93, 1449; (b) Y. Ishii, M.
Takeno, Y. Kawasaki, A. Muromachi, Y. Nishiyama and S.
Sakaguchi, J. Org. Chem., 1996, 61, 3088; (c) Orita, A.
Mitsutome and J. Otera, J. Org. Chem., 1998, 63, 2420; (d) Y.
Shirae, T. Mino, T. Hasegawa, M. Sakamotoa and T. Fujitab,
Terahedron Lett., 2005, 46, 5877; (e) M. Trost and T. Mino, J.
Am. Chem. Soc., 2003, 125, 2410; (f) P. Ilankumaran and J. G.
Verkade, J. Org. Chem., 1999, 64, 9063; (g) J. W. J. Bosco and
A. K. Saikia, Chem. Commun., 2004, 1116; (h) A. Kamal, M.
Naseer, A. Khan, K. Srinivasa Reddy, Y. V. V. Srikanth and T.
Krishnaji, Terahedron Lett., 2007, 48, 3813; (i) M.-H. Lin and
dione (6a). Yield: 81% (using vinyl acetate); greenish yellow solid;
mp: 269-271 °C; IR (KBr) ν: 3443, 3272, 2956, 2869, 1641, 1412,
-1 1
1
0
2
=
6
727, 1144, 1020, 802 cm . H NMR (400 MHz, DMSO-d ): δ (ppm)
.79 (d, 3H, J = 6.4 Hz), 0.98 (dd, 12H, J = 10.1 & 4.6 Hz), 2.05 (dd,
H, J = 15.9 & 3.5 Hz), 2.18 (td, 4H, J = 16.7 & 4.4 Hz), 2.33 (dd, 2H, J
1
3
17.0 & 4.2 Hz), 3.68 (q, 1H, J = 6.4 Hz), 9.05 (s, 1H). C NMR: (100
MHz, DMSO-d
6
): δ (ppm) 22.0, 22.3, 26.9, 29.6, 32.6, 50.6, 112.5,
+
1
50.3, 195.0. HRMS (ESI) m/z calcd. for C18
10.1783, found: 310.1779.
H25NO
2
[M+Na] :
3
9
-methyl-3,4,6,7,9,10-hexahydroacridine-1,8-(2H,5H)-dione (6b).
T. V. R. Babu, Org. Lett., 2000,
Omori, T. Okuno and Y. Tamura, Synlett, 1993,
Itoh, S. Han, Y. Matsushita and S. Hayase, Green Chem.,
2004, , 437; (l) V. Framis, F. Camps and P. Clapés,
2
, 997; (j) Y. Kita, H. Maeda, K.
Yield: 87% (using vinyl acetate), 81% (using vinyl benzoate); yellow
4, 273; (k) T.
solid; mp: 298-299 °C; IR (KBr) ν: 3442, 3276, 2953, 1632, 1413,
-1 1
1
0
2
242, 1138, 1020, 801 cm . H NMR (400 MHz, DMSO-d ): δ (ppm)
6
6
.76 (d, 3H, J = 6.5 Hz), 1.75-1.94 (m, 4H), 2.12-2.28 (m, 4H), 2.34-
Tetrahedron Lett., 2004, 45, 5031; (m) P. M Dinh, J. A
Howarth, A. R Hudnott, J. M. J. Williams and W. Harris,
Tetrahedron Lett., 1996, 37, 7623.
1
3
.45 (m, 4H), 3.71 (q, 1H, J = 6.5 Hz), 9.17 (s, 1H). C NMR: (100
MHz, DMSO-d
6
): δ (ppm) 21.5, 22.3, 22.8, 26.7, 37.3, 114.1, 151.8,
+
1
95.5. HRMS (ESI) m/z calcd. for C H NO [M+Na] : 254.1157,
2
3
4
(a) N. Isambert, M. Cruz, M. J.Are´valo, E.Go´ mez, and R.
Lavilla, Org. Lett., 2007, 21, 4200; (b) M. Kidwai, N. K. Mishra
and A. Jahan, Chin. Chem. Lett., 2011, 22, 417.
1
4
17
2
found: 254.1149.
(a) P. K. Mahata, O. Barun, H. Ila and H. Junjappa, Synlett,
2
,2’-(ethane-1,1-diyl)bis(3-hydroxy-5,5-dimethylcyclohex-2-enone)
7a). Yield: 79% (using vinyl acetate), 75% (using vinyl benzoate);
yellow solid; mp: 127-129 °C; IR (KBr) ν: 3441, 3272, 2961, 1642,
2
000, 9, 1345; (b) V. Nadaraj, S. Kalaivani and S. T. Selvi,
(
Indian J. Chem., 2007, 46B, 1703.
M. Kumar, S. Bagchi and A. Sharma, Org. Biomol. Chem.,
Submitted.
-1 1
1
6
572, 1411, 1021, 804 cm . H NMR (400 MHz, DMSO-d ): δ (ppm)
1
.01 (s, 12H), 1.40 (d, 3H, J = 5.1 Hz), 2.11 (s, 4H), 2.65 (s, 4H), 3.1
1
4 | J. Name., 2012, 00, 1-3
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DOI: 10.1039/C5RA10073A
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COMMUNICATION
5
(a) M. Kumar, T. Kaur, V. K. Gupta and A. Sharma, RSC Adv.,
015, , 17087. (b) V. Nair, R. S. Menon, A. U. Vinod and S.
2
5
Vijji, Tetrahedron Lett., 2002, 43, 2293; (c) A. Shaabani, M. B.
Teimouri, S. Samadi and K. Soleimani, Synth. Commun., 2005,
3
5
, 535; (d) J. Wu, Chem. Lett., 2006, 35, 118; (e) M. Adib, M.
Mahdavi, S. Bagherzadeh and H. R. Bijanzadeh, Synlett, 2009,
, 2542.
15
6
7
B. Ganem, Acc. Chem. Res., 2009, 42, 463.
M. T. Maghsoodlou, N. Hazeri, Habibi-Khorassani, M. Sayyed,
V. Solimani, G. Marandi and Z. Razmjoo, J. Chem. Res., 2008,
4, 198.
8
9
M. N. Pennell, R. W. Foster, P. G. Turner, H. C. Hailes, C. J.
Tameband and T. D. Sheppard, Chem. Commun., 2014, 50
302.
B. Baghernejad,
,
1
M. M. Heravi, H. A. Oskooie, N.
Poormohammad, M. Khorshidi and Y. S. Beheshtiha, Mol
Divers., 2011, 15, 245.
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