Copper catalyzed coupling of protecting group free and sterically hindered 2-bromobenzyl tertiary alcohols with phenols and anilines: Facile synthesis of xanthenes and dihydroacridines

Article abstract of DOI:10.1039/c6ra03447k

A simple and efficient method for the synthesis of xanthenes and dihydroacridines containing a quaternary carbon atom at the 9^th-position, is presented. Significantly, the protocol facilitated the smooth participation of sterically hindered and protecting group free 2-bromobenzyl tertiary alcohols in cross coupling reactions with phenols and anilines, under copper-catalysis. The Lewis acid mediated intramolecular C-C bond formation enabled the formation of a quaternary carbon atom at the 9^th-position. Remarkably, this two-step protocol required a single column purification technique.

Full text of DOI:10.1039/c6ra03447k

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Copper Catalyzed Coupling of Protecting Group Free and Sterically
Hindered 2-Bromobenzyl Tertiary Alcohols with Phenols and
Anilines: Facile Synthesis of Xanthenes and Dihydroacridines
Received 00th January 20xx,
Accepted 00th January 20xx
Lodi Mahendar and Gedu Satyanarayana
DOI: 10.1039/x0xx00000x
www.rsc.org/
Abstract: A simple and efficient method for the synthesis of xanthenes and dihydroacridines containing a quaternary
carbon atom at 9th-position, is presented. Significantly, the protocol facilitated the smooth participation of sterically
hindered and protecting group free 2-bromobenzyl tertiary alcohols in cross coupling reaction with phenols and anilines,
under copper-catalysis. The Lewis acid mediated intramolecular C-C bond formation enabled the formation of quaternary
carbon atom at 9th-position. Remarkably, this two-step protocol required single column purification technique.
On the other hand, acridines are another class of important
Introduction
nitrogen containing heterocyclic compounds, in which the oxygen
atom of xanthenes replaced with nitrogen and with complete
Xanthenes1 and xanthones2 are special class of tricyclic
dibenzopyrans, since these skeletons constitutes pharmaceutically
important compounds and natural products as well. Their other
uses include dyes or fluorescent materials and chiroptical molecular
aromatization. Acridines are also well known for their broad range
of biological and medicinal properties.8 In this regard, some
important natural and unnatural products are as shown in Figure 1.
Notably, dihydroacridine analogue found as selective activator of
temperature- and mechano-sensitive K2P channels.9 Since it is
certain that acridines are indispensable compounds, development
of efficient protocols for their synthesis is very much essential.
Apart from the well-established named reaction (Bernthsen
acridine synthesis), recently, there are good number of approaches
developed for the synthesis of acridines from eminent research
groups.10 In continuation of our on-going research interests on
transition-metal mediated efficient transformations,11 herein we
disclose an efficient method for synthesis of xanthenes and
dihydroacridines containing a quaternary carbon atom at 9th-
position. This protocol enabled the accomplishment of xanthenes
and dihydroacridines with simple to dense functionality on the
aromatic ring. Significantly, this two-step process required a single
column chromatographic technique.
switches.3 They exhibit
a variety of physicochemical and
pharmacological properties (e.g. anti-oxidants, anti-bacterial, anti-
tumoral, anti-neoplastics, vasodilators and anti-inflammatory
activities).4 Interestingly, their biological behaviour depends upon
the nature and position of substituents on their structure.5 Some of
the notable natural and unnatural compounds are as depicted in
Figure 1. Vowing to their occurrence from natural sources of
biological relevance and pharmaceutical reputation of analogues
compounds, prompted organic chemists to design and develop new
synthetic methods to establish functionalized xanthenes. Though a
good number of methods established for their synthesis, most of
them either require pre-synthesized precursors or involve multi-
step protocols.6 On the other hand, one-step processes for their
synthesis are very few.7 Particularly, some of the established
strategies affording 9-substituted xanthenes, have some limitations,
either due to low yields or require multiple steps. Therefore, it is
highly desirable to develop new and efficient methods to achieve 9-
substituted xanthenes.
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natural and unnatur al xanthenes:
HO
HO
O
HO
HO
O
HO
HO
O
O
OMe
O
O
OMe
OH
O
OMe
O
O
OMe
HO
OH
OH
O
Me
O
Me
1
2
3
4
1
4
xanthones to isolated from the fermentation culture of the endophytic fungus Xylaria sp. FRR 5657
O
O
OMe
Me
Me
O
Me
O
O
OH
O
Me
O
Me
O
OH
OH
O
O
MeO
HO
MeO
O
OMe
Me
O
OH
psorospemin
OH
O
OH
8
H
O
OH
5
6
α
7
bikaverin
-mangostin
rufescidride
OH
O
Me OMe
HO
O
HO
blumeaxanthene
O
11
OH
O
O
OH
X
O
X = OH, fluorescein
X = NR2, rhodamine 13
X
X R2N
O
NR2
9
10
rosamine
12
fluorone
Me
O
natural and unnatur al acridines:
Me Me
N
Cl
Cl
O
OH
O
OMe
OMe
OMe
selective activator of temperature- and
mechano-sensitive K2P channels
HO
N
N
O
OMe Me OMe
Me
acronycine
Me
Me
14
15
16
N
NH
glyfoline
N
N
Me
Me
N
NH2
NH2
N
HN
N
Me
OH
OMe
Me
H2N
N
porflavine 18
NH2
N
Cl
HO
tacrine 17
acrisorcin 19
mepacrine 20
Figure 1: Some of the notable examples of natural/unnatural xanthones (1 to 7), xanthenes (8 to 13), acridones (14 to 15), dihydroacridine
(16) and acridines (17 to 20).
Moreover, to the best of our knowledge, there is no report on the
Result and Discussion
direct synthesis of xanthenes/acridines with a quaternary carbon
atom at 9th-position. Further, 9,9-dimethylxanthene was identified
Though methods were known for the synthesis of 9-substititued
as the useful synthon, for the synthesis of novel ligands (xanthphos
etc.),12 which were proved to be vital in metal-catalysis. All earlier
reports for the synthesis of 9,9-dimethylxanthene accomplished
using xanthone as the synthetic precursor through di-methylation
with trimethylaluminium (AlMe3).13 With these observations, it was
prompted us to develop new and efficient method for the synthesis
xanthenes/acridines, most of them were made with the tertiary
carbon atoms at 9th-position. Also, many of them were based on
multistep processes or using derivatization of simple xanthenes.
Whereas, most of one-pot protocols were limited to the synthesis
of simple xanthenes without any substitution at 9th-carbon centre.
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of xanthenes and acridines with a quaternary carbon atom at 9th-
position, which may not only open a path for accomplishment of
new compounds of biological relevance but also could further
expand scope to develop new sort of ligands in-order to prepare
efficient metal-catalysts. In our laboratory, recently, we have
demonstrated the efficient and domino one-pot conversions of 2-
bromotertiary benzyl alcohols into novel heterocyclic compounds
using transition-metal catalysis. With this background, we
envisioned that xanthenes 21 and dihydroacridines 22 could be
obtained from sterically hindered and protecting free 2-
bromotertiary benzyl alcohols 23 using copper-catalyzed Buchwald-
Hartwig coupling with phenols 24/anilines 25 and acid induced
intramolecular C-C bond formation (Scheme 1).
Table 1
:
Optimization conditions for the formation of biaryl ether
26aa.
Entry a
Base (2 equiv)
Na2CO3
K2CO3
Solvent
toluene
toluene
toluene
toluene
toluene
DMF
Yield of 26aab
50% + SMc
84%
1
2
3
4
5
6
7
8
9
K3PO4
76%
NaHCO3
Cs2CO3
Cs2CO3
Cs2CO3
Cs2CO3
Cs2CO3
SM
91%
73%
DMA
72%
DMSO
CH3CN
65% + SMc
53% + SMc
aAll reactions were carried out on 0.5 mmol of 23a and 1 mmol of 24a in 0.5 mL
solvent. bIsolated yields of chromatographically pure products. cStarting material also
recovered along with the product.
Scheme 1: Retrosynthetic analysis to give 21/22 from alcohols 23
and phanols 24/anilines 25.
With the optimized reaction conditions in hand (Table 1, entry
5), to check the scope of the method, we explored the reaction
between 2-bromotertiary benzyl alcohols 23a/23e and phenols
24a/24b and aninlines 25a/25b. To our delight, the reaction found
amenable and furnished the biaryl ethers 26aa/24eb and coupled
anilines 27aa/27ab, in very good to excellent yields (Table 2).
To initiate the synthetic study, first we decided to examine the
coupling reaction between the simple tertiary alcohol 23a and the
phenol 24a. Thus, the reaction was performed in the presence of
catalyst CuI (10 mol %)/1,10-phen (20 mol %), base Na2CO3 (2 equiv)
in toluene at 110 °C for 24 h. As anticipated, the product 26aa was
obtained in moderate yield along with the unreacted starting
material 23a (Table 1, entry 1). To our delight, as we presumed, the
tertiary alcohol moiety was not interfered in the reaction. This may
be due to the fact that though the tertiary hydroxyl group is more
nucleophilic than phenolic OH, the steric hindrance around the tert-
OH moiety might be severe and not allowed it to participate in the
competitive intermolecular coupling. Also, it was well
demonstrated in one of our earlier reports that this tertiary alcohol
did not prefer intramolecular coupling to give oxetane derivatives.
Interestingly, with bases K2CO3 and K3PO4, gave the product 26aa, in
very good yields (Table 1, entries 2 & 3). While, no progress was
noted with mild base NaHCO3 (Table 1, entry 4). To our delight, the
reaction with the strong base Cs2CO3, furnished the product 26aa,
in excellent yield (Table 1, entry 5). On the other hand, the solvents
DMF and DMA instead of toluene with base Cs2CO3, gave good
yields of the product 26aa (Table 1, entries 6 & 7). However, the
reactions in other solvents such DMSO and CH3CN were found
further inferior (Table 1, entries 8 & 9).
With these coupled ethers 26aa/26eb and anilines 27aa/27ab,
we next planned for acid promoted intramolecular C-C bond
formation. Thus, the reaction was carried out with the Lewis acid
BF3⋅OEt2 in DCM at 0 °C to rt for 30 min. Gratifyingly, the reaction
was quite successful and furnished the corresponding xanthenes
21aa/21eb and dihydroacridines 22aa/22ab, in good to excellent
yields (Table 3).
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Table 2
Journal Name
cFor final compounds 21aa & 21eb, the first alphabet represents from 2-bromobenzyl
tertiary alcohols 23a & 23e, while second letter indicates the phenols 24a & 24b. dFor
:
Synthesis of biaryl ethers 26aa/26eb and coupled anilines
27aa/27ab.a,b,c,d
final compounds 22aa
& 22ab the first alphabet represents from 2-bromobenzyl
tertiary alcohol 23a, while second letter indicates the anilines 25a & 25b.
After the accomplishment of xanthenes 21aa/21fa and
dihydroacridines 22aa/22ab, we thought that protocol can be made
still more efficient by conducting acid mediated cyclization directly
on the concentrated crude reaction mixture of biaryl ethers 26 and
coupled anilines 27 without column purification, so that we may
end up in doing a single column chromatography for two-steps
together. Thus, initially, we have directly treated the crude biaryl
ethers 26aa-26gb with BF3⋅OEt2. To our delight, as expected,
afforded the xanthenes 21aa-21gb, in good to very good yields
(Table 4), thus enable us to make the method more efficient and
interesting.
Table 4: Synthesis of xanthenes 21aa-21gb.a,b,c
Reaction conditions: a23a & 23e (0.50 mmol), 24a & 24b (1.00 mmol), CuI (10 mol %),
1,10-phenanthroline (20 mol %), Cs2CO3 (1.0 mmol), in 0.5 mL toluene, at 110 °C for 24
h. bIsolated yields of chromatographically pure products. cFor final compounds 26aa &
26eb, the first alphabet represents from 2-bromobenzyl tertiary alcohols 23a & 23e,
while second letter indicates the phenols 24a & 24b. dFor final compounds 27aa & 27ab
the first alphabet represents from 2-bromobenzyl tertiary alcohol 23a, while second
letter indicates the anilines 25a & 25b.
Table 3: Synthesis of xanthenes 21aa/21eb and dihydroacridines
22aa/22ab.a,b,c,d
Reaction conditions: a(26aa, 26eb) & (27aa, 27ab) (0.25 mmol), BF3⋅OEt2 (2 equiv), in 2
mL DCM, at 0 °C to rt for 30 min. bIsolated yields of chromatographically pure products.
4 | J. Name., 2012, 00, 1-3
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Reaction conditions: a23a-23g (0.50 mmol), 24a-24b (1.00 mmol), CuI (10 mol %), 1,10-
phenthroline (20 mol %), Cs2CO3 (1.0 mmol), in 0.5 mL toluene, at 110 °C for 24 h then
work up and evaporated under vacuum added BF3⋅OEt2 (2 equiv) in 2 mL DCM, at 0 °C
to rt for 30 min. bisolated yields of chromatographically pure products. cFor xanthenes
21aa-21gb, the first alphabet represents from 2-bromobenzyl tertiary alcohols 23a-23g,
while second letter indicates the anilines 24a-24b.
Table 5
:
Synthesis of xanthenes 22aa-22hb.a,b,c
1) CuI (10 mol %)
1,10-phen (20 mol %)
Cs2CO3, toluene
110 C, 24 h
2) crude 27aa-27hb
BF3.OEt2, DCM
R2 R3
XH
R2 R3
OH
+
R1
R1
R4
R4
Br
23a-23h
X
22aa-22hb
25a-25c
0
C to rt, 30 min
X = NH, NAr
single column purification
Similarly, the crude coupled anilines 27aa-27bh were subjected
to BF3⋅OEt2 induced cyclization. Quite interestingly, as anticipated,
the strategy was also proved amenable and furnished the
dihydroacridines 22aa-22hb (Table 5). Remarkably, the reaction was
also successful with strong electron withdrawing nitro group (22ac,
Table 5). Thus reveals the significance of the present strategy. It is
worth noting that the reaction with 2-bromobenzyl secondary
alcohols was unclear (i.e. neither starting material nor the product
was isolated). This is in accordance with our earlier observations
that only 2-bromobenzyl tertiary alcohols were suitable for
intermolecular Sonogashira11e and cyanations11f followed by
intramolecular nucleophilic attacks, under copper catalysis,
whereas the reaction was unclear with the corresponding primary
or secondary alcohols, under standard reaction conditions.
Me Me
Me Me
OH
NH2
N
H
Br
23a
25a
22aa 71%
Me Me
Me Me
OH
NHPh
N
Br
23a
Ph
22ab 77%
25b
NH2
Me Me
Me Me
OH
NO2
N
H
NO2
25c
Br
23a
22ac 68%
Me
Me
Me
Me
NHPh
OH
N
Br
23b
Ph
25b
22bb 71%
Me Me
MeO
Me Me
OH
NHPh
MeO
MeO
N
Br
Ph
22db 80%
Me
23d
23e
25b
Me
Me
Me
MeO
NHPh
OH
N
Br
Ph
22eb 81%
25b
Me Me
MeO
MeO
Me Me
OH
NHPh
MeO
MeO
N
Br
Ph
22fb 81%
23f
25b
Me Me
Me Me
OH
NHPh
O
O
O
O
N
Br
Ph
22hb 79%
23h
25b
Reaction conditions: a23a-23h (0.50 mmol), 25a-25c (1.00 mmol), CuI (10 mol %), 1,10-
phenthroline (20 mol %), Cs2CO3 (1.0 mmol), in 0.5 mL toluene, at 110 °C for 24 h then
work up and evaporated under vacuum added BF3⋅OEt2 (2 equiv) in 2 mL DCM, at 0 °C
to rt for 30 min. bisolated yields of chromatographically pure products. cFor
dihydroacridines 22aa-22hb, the first alphabet represents from 2-bromobenzyl tertiary
alcohols 23a-23h, while second letter indicates the anilines 25a-25c.
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In addition to the spectroscopic evidence for the structural toluene were dried over sodium metal, DCM and DMF were dried
confirmation of xanthenes 21 and dihydroacridines 22, the over calcium hydride.
structures were confirmed by the single crystal x-ray diffraction
All the solvents (diethyl ether, DCM, DMF) are commercially
analysis of 21ab and 22ac Figure 2 (see; supporting information).
available. All small scale dry reactions were carried out using
standard syringe-septum technique. Reactions were monitored by
TLC on silica gel using a combination of petroleum ether and ethyl
acetate as eluents. Reactions were generally run under inert
atmosphere. Solvents were distilled prior to use; petroleum ether
with a boiling range of 40 to 60  C was used. Acmes silica gel (60–
120 mesh) was used for column chromatography (approximately 20
21ab
22ac
g per one gram of crude material).
Figure 2. X-ray crystal structure of product 21ab and 22ac. Thermal
ellipsoids are drawn at 50% probability level.
General Procedure-1 (For the synthesis of aryl ethers 26 and aryl
amines 27):
Conclusion
:
In summary, we have disclosed a simple and efficient method
for the synthesis of xanthenes and acridines containing
In an oven-dried Schlenk tube 2-bromobenzyl tertiary
alcohols 23 (0.5 mmol), phenols 24 or anillines 25 (1.00 mmol), CuI
(10 mol %), 1,10-phenthroline (20 mol %), Cs2CO3 (1.0 mmol) and
solvent toluene (0.5 mL) were added. The resulting reaction mixture
a
quaternary carbon atom at 9th-position. Significantly, sterically
hindered and protecting group free 2-bromobenzyl tertiary alcohols
were involved in smooth coupling reaction with phenols and
anilines, under copper-catalysis. The Lewis acid mediated
intramolecular C-C bond formation enable the formation of
quaternary carbon atom at 9th-position. Remarkably, this two-step
protocol required single column purification technique.
was stirred at 110 °C for 24 h. The progress of the reaction was
monitored by TLC. After completion of the reaction, the reaction
mixture was allowed to cool to room temperature, then saturated
aqueous NH4Cl was added fallowed by extraction with ethyl
acetate. The organic layers were dried (Na2SO4) and concentrated in
vacuo. Purification of the residue by silica gel column
chromatography using petroleum ether/ethyl acetate as the eluent
furnished the aryl ethers 26 and aryl amines 27.
Experimental Section
General Procedure-2 (For the synthesis of xanthenes 21 and
dihydroacridines 22):
General Considerations
IR spectra were recorded on a FTIR spectrophotometer. 1H
NMR spectra were recorded on 400 MHz spectrometer at 295 K in
CDCl3; chemical shifts (δ ppm) and coupling constants (Hz) are
reported in standard fashion with reference to either internal
standard tetramethylsilane (TMS) (δH=0.00 ppm) or CHCl3 (δH=7.25
ppm). 13C NMR spectra were recorded on 100 MHz spectrometer at
RT in CDCl3; chemical shifts (δ ppm) are reported relative to CHCl3
[δC=77.00 ppm (central line of triplet)]. In the 13C NMR, the nature
of carbons (C, CH, CH2, and CH3) was determined by recording the
DEPT-135 spectra and is given in parentheses and noted as s =
singlet (for C), d = doublet (for CH), t = triplet (for CH2) and q = -
In an oven-dried Schlenk tube aryl ethers 26 or aryl amines
27 (0.25 mmol) dissolved in 2 mL dry DCM, BF3⋅OEt2 (2 equiv) was
added at 0 °C. The resulting reaction mixture was stirred at 0 °C to
rt for 30 min. The progress of the reaction was monitored by TLC.
After completion of the reaction, the reaction mixture was diluted
with (10 mL) water and extracted with DCM fallowed by washed
with NaHCO3. The organic layers were dried (Na2SO4) and
concentrated in vacuo. Purification of the residue by silica gel
column chromatography using petroleum ether/ethyl acetate as the
eluent furnished the xanthenes 21 and dihydroacridines 22.
1
quartet (for CH3). In the H NMR, the following abbreviations were
General Procedure-3 (For the synthesis of xanthenes 21 and
dihydroacridines 22 using single column purification):
used throughout: s = singlet, d = doublet, t = triplet, q = quartet, qui
=quintet, m = multiplet and br s. = broad singlet. The assignment of
signals was confirmed by 1H, 13C CPD (carbon proton decoupled),
and DEPT spectra. High-resolution mass spectra (HR-MS) were
recorded using Q-TOF multimode source. Melting points were
determined on an electrothermal melting point apparatus and are
uncorrected. Benzaldehydes, methyl iodide, bromoethane, Mg
metal and Na2SO4 were commercially available (local made) used
without further purification. CuI, 1,10-Phenthroline and Cs2CO3
In an oven-dried Schlenk tube 2-bromobenzyl tertiary
alcohol 23 (0.5 mmol), phenols 24 or anilline 25 (1.00 mmol), CuI
(10 mol %), 1,10-phenthroline (20 mol %), Cs2CO3 (1.0 mmol) and
toluene (0.5 mL) were added. The resulting reaction mixture was
stirred at 110 °C for 24 h. After completion of reaction, the reaction
mixture was allowed to cool to room temperature, then diluted
with (10 mL) ethyl acetate and water was added fallowed by
extraction with ethyl acetate. The organic layers were dried
purchased from Sigma-Aldrich, while BF3⋅OEt2 was used from local
commercial sources. All dry solvents were used, diethyl ether and
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(Na2SO4) and concentrated in vacuo. The crude reaction mixture of This compound was prepared according to the GP-3 and isolated as
aryl ethers 26 and aryl amines 27 was dissolved in 2 mL dry DCM,
BF3 OEt2 (2 equiv) was added at 0 °C. The resulting reaction mixture ether/ethyl acetate 9:1, Rf(23aa)=0.60, Rf(21aa)=0.80, UV
white color solid 70% yield (90 mg): mp: 98-100 °C; [TLC (petroleum
⋅
detection]. IR (MIR-ATR, 4000–600 cm-1):
νmax=2930, 1625, 1575,
was stirred at 0 °C to rt for 30 min. The progress of the reaction was
monitored by TLC. After completion of reaction, the reaction
mixture was diluted with (10 mL) water and extracted with DCM
fallowed by washed with NaHCO3. The organic layers were dried
(Na2SO4) and concentrated in vacuo. Purification of the residue by
silica gel column chromatography using petroleum ether/ethyl
acetate as the eluent furnished the xanthenes 21 and acridines 22.
2-(2-phenoxyphenyl)propan-2-ol (26aa):
1491, 1336, 1245, 1142, 1036, 956, 811, 747, 666 cm-1. 1H NMR
(CDCl3, 400 MHz): δ=8.48 (d, 1H, J=8.8 Hz), 7.82 (d, 1H, J=8.3 Hz),
7.71 (d, 1H, J=8.8 Hz), 7.51 (d, 2H, J=7.8 Hz), 7.38 (dd, 1H, J=6.8 and
8.3 Hz), 7.22 (dd, 2H, J=6.4 and 8.8 Hz), 7.13 (dd, 1H, J=7.3 and 7.8
Hz), 7.03 (d, 1H, J=7.8 Hz), 2.16 (s, 6H, CH3) ppm. 13C NMR (CDCl3,
100 MHz): δ=147.7 (s, Cq), 147.3 (s, Cq), 132.0 (s, Cq), 131.8 (s, Cq),
131.7 (s, Cq), 129.7 (d, CH), 129.4 (d, CH), 127.7 (d, CH), 127.2 (d,
CH), 126.0 (d, CH), 125.6 (d, CH), 123.3 (d, CH), 123.1 (d, CH), 119.8
(s, Cq), 118.5 (d, CH), 115.7 (d, CH), 34.6 (s, Cq), 32.5 (q, 2C, CH3)
ppm. HR-MS (ESI+) m/z calculated for [C19H17O]+=[M+H]+: 261.1274;
This compound was prepared according to the GP-1 and isolated as
pale yellow color oil 91% yield (103 mg): [TLC (petroleum
ether/ethyl acetate 9:1, Rf(23a)=0.60, Rf(26aa)=0.60, UV detection].
IR (MIR-ATR, 4000–600 cm-1):
νmax=3416, 2971, 1576, 1481, 1442, found 261.1262.
1364, 1224, 1162, 1072, 854, 752, 690 cm-1. 1H NMR (CDCl3 400 12-ethyl-12-methyl-12H-benzo[a]xanthene (21bb):
MHz): δ=7.51 (d, 1H, J=7.8 Hz), 7.36 (dd, 2H, J=8.8 and 7.3 Hz), 7.15 This compound was prepared according to the GP-3 and isolated as
(d, 2H, J=7.8 Hz), 7.10-7.00 (m, 3H), 6.79 (d, 1H, J=7.8 Hz), 1.68 (s, pale yellow color oil 73% yield (99 mg): [TLC (petroleum ether/ethyl
6H, CH3) ppm. 13C NMR (CDCl3, 100 MHz): δ=156.4 (s, Cq), 154.9 (s, acetate 9:1, Rf(23b)=0.50, Rf(21bb)=0.60, UV detection]. IR (MIR-
Cq), 138.2 (d, CH), 129.9 (d, 2C, CH), 128.1 (d, CH), 126.3 (d, CH),
ATR, 4000–600 cm-1):
νmax=2964, 1588, 1491, 1342, 1247, 1142,
1052, 957, 812, 749, 670 cm-1. 1H NMR (CDCl3, 400 MHz): δ=8.47 (d,
1H, J=8.8 Hz), 7.79 (d, 1H, J=8.3 Hz), 7.69 (d, 1H, J=8.8 Hz), 7.47 (d,
1H, J=6.8 Hz), 7.44 (dd, 1H, J=6.8 and 7.8 Hz, Ar-H), 7.36 (dd, 1H,
J=6.8 and 7.8 Hz), 7.19 (d, 2H, J=8.8 Hz), 7.10 (dd, 1H, J=7.8 and 8.8
Hz), 6.99 (d, 1H, J=7.8 Hz), 2.93 - 3.06 (m, 1H, CH2), 2.15 (s, 3H, CH3),
1.97–2.08 (m, 1H, CH2), 0.49 (t, 3H, J=7.3 Hz, CH3) ppm. 13C NMR
(CDCl3, 100 MHz): δ=149.5 (s, Cq), 148.9 (s, Cq), 132.0 (s, Cq), 131.8
123.8 (d, CH), 123.2 (d, CH), 119.4 (d, 2C, CH), 118.7 (d, CH), 72.4 (s,
Cq), 30.0 (q, 2C, CH3) ppm. HR-MS (ESI+) m/z calculated for
[C15H15O]+=[(M+H)-H2O]+: 211.117; found 211.1118.
2-(5-methoxy-2-(naphthalen-2-yloxy)phenyl)butan-2-ol (26eb):
This compound was prepared according to the GP-3 and isolated as
pale yellow color viscous liquid 90% yield (144 mg): [TLC (petroleum
ether/ethyl acetate 9:1, Rf(23e)=0.40, Rf(26eb)=0.40, UV detection].
IR (MIR-ATR, 4000–600 cm-1):
νmax=3447, 2964, 1598, 1461, 1251, (s, Cq), 129.7 (d, CH), 129.4 (d, CH), 129.2 (s, Cq), 127.1 (d, 2C, CH),
1194, 1037, 961, 810, 742 cm-1. H NMR (CDCl3, 400 MHz): δ=7.85- 125.6 (d, 2C, CH), 123.3 (d, CH), 123.2 (d, CH), 118.4 (d, CH), 117.0
7.76 (m, 2H, Ar-H), 7.68 (d, 1H, J=7.8 Hz, Ar-H), 7.50-7.35 (m, 2H, Ar- (s, Cq), 115.3 (d, CH), 39.9 (s, Cq), 36.0 (t, CH2), 31.9 (q, CH3), 10.5 (t,
H), 7.30-7.20 (m, 2H, Ar-H), 7.14 (d, 1H, J=3.4 Hz, Ar-H), 6.85 (d, 1H, CH3] ppm. HR-MS (ESI+) m/z calculated for [C20H19O]+=[M+H]+:
J=8.8 Hz, Ar-H), 6.74 (dd, 1H, J=8.8 and 2.9 Hz, Ar-H), 3.83 (s, 3H, Ar- 275.1430; found 275.1428.
1
OCH3), 2.15-2.00 (m, 1H, CH2), 1.95-1.80 (m, 1H, CH2), 1.61 (s, 3H, 12,12-diethyl-12H-benzo[a]xanthene (21cb):
CH3), 0.84 (t, 3H, J=7.3 Hz, CH3) ppm. 13C NMR (CDCl3, 100 MHz): This compound was prepared according to the GP-3 and isolated as
δ=155.6 (s, Ar-C), 155.5 (s, Ar-C), 147.3 (s, Ar-C), 139.4 (s, Ar-C),
134.3 (s, Ar-C), 129.9 (d, Ar-CH), 127.7 (d, Ar-CH), 127.0 (d, Ar-CH),
126.6 (d, Ar-CH), 124.6 (d, Ar-CH), 121.2 (d, Ar-CH), 119.3 (d, Ar-CH),
113.4 (s, Ar-CH), 113.1 (d, Ar-CH), 112.6 (d, Ar-CH), 75.1 (s, Ar-C),
55.6 (q, OCH3), 34.8 (t, CH2), 27.7 (q, CH3), 8.7 (q, CH3) ppm. HR-MS
(ESI+) m/z calculated for [C21H22NaO3]+=[M+Na]+: 345.1461; found
345.1457.
white color solid 83% yield (118 mg): mp: 86-88
ether/ethyl acetate 9:1, Rf(23c)=0.50, Rf(21cb)=0.70, UV detection].
IR (MIR-ATR, 4000–600 cm-1):
max=2964, 1587, 1491, 1350, 1242,
°C; [TLC (petroleum
ν
1131, 1037, 961, 812, 747, 671 cm-1. 1H NMR (CDCl3, 400 MHz):
δ=8.53 (d, 1H, J=8.8 Hz), 7.80 (d, 1H, J=7.8 Hz), 7.70 (d, 1H, J=8.8
Hz), 7.46 (dd, 1H, J=7.3 and 8.8 Hz), 7.40 (dd, 1H, J=7.3 and 7.8 Hz),
7.36 (dd, 1H, J=6.8 and 7.8 Hz), 7.20 (d, 2H, J=8.8 Hz), 7.10 (dd, 1H,
J=7.3 and 8.3 Hz), 7.00 (d, 2H, J=8.3 Hz), 2.95–3.08 (m, 2H, CH2),
1.98–2.11 (m, 2H, CH2) 0.51 (t, 6H, J=7.3 Hz, CH3) ppm. 13C NMR
(CDCl3, 100 MHz): δ=151.1 (s, Cq), 150.4 (s, Cq), 132.2 (s, Cq), 131.7
(s, Cq), 129.7 (d, CH), 129.5 (d, CH), 127.1 (d, CH), 126.5 (s, Cq), 126.4
(d, CH), 125.6 (d, CH), 125.1 (d, CH), 123.3 (d, CH), 123.2 (d, CH),
118.4 (d, CH), 115.2 (d, CH), 114.3 (s, Cq), 46.0 (s, Cq), 34.8 (t, CH2),
10.2 (q, CH3) ppm. HR-MS (ESI+) m/z calculated for
[C21H21O]+=[M+H]+: 289.1587; found 289.1577.
2-(2-(diphenylamino)phenyl)propan-2-ol (27aa):
This compound was prepared according to the GP-1 and isolated as
black color semi solid 86% yield (130 mg): [TLC (petroleum
ether/ethyl acetate 9:1, Rf(23a)=0.60, Rf(27aa)=0.70, UV detection].
IR (MIR-ATR, 4000–600 cm-1):
νmax=3396, 2975, 1587, 1486, 1258,
1161, 907, 821, 728, 693 cm-1. 1H NMR (CDCl3, 400 MHz): δ=7.56-
7.50 (m, 1H), 7.30-7.15 (m, 6H), 7.10-7.04 (m, 1H), 7.03-7.93 (m,
6H), 5.11 (br s, 1H), 1.36 (s, 6H) ppm. 13C NMR (CDCl3, 100 MHz):
δ=148.2 (s, 2C, Cq), 146.0 (s, Cq), 143.9 (s, Cq), 132.7 (d, CH), 129.1
(d, 4C, CH), 128.3 (d, CH), 127.8 (d, CH), 127.0 (d, CH), 122.6 (d, 6C,
CH), 73.6 (s, Cq), 31.2 (q, 2C, CH3) ppm. HR-MS (ESI+) m/z calculated
for [C21H22NO]+=[M+H]+: 304.1696; found 304.1695.
10-methoxy-12,12-dimethyl-12H-benzo[a]xanthene (21db):
This compound was prepared according to the GP-3 and isolated as
white color solid 82% yield (118 mg): mp: 92-94
°C; [TLC (petroleum
ether/ethyl acetate 9:1, Rf(23d)=0.40, Rf(21db)=0.60, UV detection].
IR (MIR-ATR, 4000–600 cm-1):
ν
max=2932, 1577, 1498, 1338, 1240,
12,12-dimethyl-12H-benzo[a]xanthene (21aa):
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Journal Name
1173, 1042, 958, 810, 730, 601 cm-1. 1H NMR (CDCl3, 400 MHz): J=8.8 Hz), 7.46 (dd, 1H, J=6.8 and 8.8 Hz), 7.34 (dd, 1H, J=6.8 and 7.8
δ=8.44 (d, 1H, J=8.8 Hz), 7.80 (d, 1H, J=8.3 Hz), 7.68 (d, 1H, J=8.8 Hz), 7.14 (d, 1H, J=8.8 Hz), 6.86 (s, 1H), 6.54 (s, 1H), 3.91 (s, 3H,
Hz), 7.49 (dd, 1H, J=6.8 and 8.3 Hz), 7.36 (dd, 1H, J=6.8 and 7.8 Hz), CH3), 3.90 (s, 3H, CH3), 3.05–2.85 (m, 1H, CH2), 2.12 (s, 3H, CH3),
7.17 (d, 1H, J=8.8 Hz), 7.01 (s, 1H), 6.96 (d, 1H, J=8.8 Hz), 6.78 (d, 2.10–1.90 (m, 1H, CH2), 0.48 (t, 3H, J=7.3 Hz, CH3) ppm. 13C NMR
1H, J=8.8 Hz), 3.84 (s, 3H, CH3), 2.14 (s, 6H, CH3) ppm. 13C NMR (CDCl3, 100 MHz): δ=149.1 (s, Cq), 148.3 (s, Cq), 145.2 (s, Cq), 143.6
(CDCl3, 100 MHz): δ=155.4 (s, Cq), 147.4 (s, Cq), 142.0 (s, Cq), 132.5 (s, 1C, Cq), 132.0 (s, Cq), 131.8 (s, Cq), 129.6 (d, CH), 129.4 (d, CH),
(s, Cq), 131.8 (s, Cq), 129.6 (d, CH), 129.4 (d, CH), 125.9 (d, CH), 125.6 125.6 (d, 2C, CH), 123.2 (d, CH), 119.6 (s, Cq), 118.3 (d, CH), 116.5 (s,
(d, CH), 123.1 (d, CH), 119.3 (s, Cq), 118.8 (d, CH), 118.5 (s, Cq), 116.3 Cq), 109.5 (d, CH), 99.0 (d, CH), 56.6 (q, CH3), 55.9 (q, CH3), 39.9 (s,
(d, CH), 112.9 (d, CH), 112.7 (d, CH), 55.7 (q, CH3), 35.0 (s, CH3), 32.2 CH3), 35.4 (t, CH2), 31.6 (q, CH3), 10.5 (q, CH3) ppm. HR-MS (ESI+)
(q, 2C, CH3) ppm. HR-MS (ESI+) m/z calculated for m/z calculated for [C22H23O3]+=[M+H]+: 349.1672; found 349.1669.
[C20H19O2]+=[M+H]+: 291.1380; found 291.1376.
9,9-dimethyl-10-phenyl-9,10-dihydroacridine (22ab):
This compound was prepared according to the GP-2 and 3 isolated
12-ethyl-10-methoxy-12-methyl-12H-benzo[a]xanthene
(21eb):
as black color solid 77% yield (109 mg): mp: 116-118
(petroleum ether/ethyl acetate 9:1, Rf(23a)=0.50, Rf(22ab)=0.70, UV
detection]. IR (MIR-ATR, 4000–600 cm-1):
max=2965, 2923, 1584,
°C; [TLC
This compound was prepared according to the GP-3 and isolated as
pale yellow color viscous liquid 89% yield (134 mg): [TLC (petroleum
ether/ethyl acetate 9:1, Rf(23e)=0.40, Rf(21eb)=0.60, UV detection].
IR (MIR-ATR, 4000–600 cm-1):
νmax=2965, 1592, 1474, 1312, 1211,
ν
1473, 1450, 1331, 1263, 1061, 906, 742, 697 cm-1. H NMR (CDCl3,
400 MHz): δ=7.63 (dd, 2H, J=7.8 and 7.8 Hz), 7.51 (dd, 1H, J=7.3 and
7.3 Hz), 7.47 (d, 2H, J=7.3 Hz), 7.35 (d, 2H, J=7.3 Hz), 6.98 (dd, 2H,
J=7.3 and 7.8 Hz), 6.93 (dd, 2H, J=7.3 and 7.3 Hz), 6.27 (d, 2H, J=8.3
Hz), 1.71 (s, 6H, CH3) ppm. 13C NMR (CDCl3, 100 MHz): δ=141.2 (s,
Cq), 140.9 (s, 2C, Cq), 131.3 (d, 2C, CH), 130.8 (d, 2C, 2 CH), 129.9 (s,
2C, Cq), 128.2 (d, 2C, CH), 126.3 (d, 2C, CH), 125.1 (d, 2C, CH), 120.5
(d, 2C, CH), 114.0 (d, 2C, CH), 35.9 (s, Cq), 31.2 (q, 2C, CH3) ppm. HR-
MS (ESI+) m/z calculated for [C21H20N]+=[M+H]+: 286.1590; found
286.1596.
1
1039, 933, 879, 745, 610 cm-1. 1H NMR (CDCl3, 400 MHz): δ=8.46 (d,
1H, J=8.8 Hz), 7.79 (d, 1H, J=8.3 Hz), 7.69 (d, 1H, J=8.8 Hz), 7.47 (dd,
1H, J=6.8 and 8.3 Hz), 7.36 (dd, 1H, J=6.8 and 7.8 Hz), 7.17 (d, 1H,
J=8.8 Hz), 6.97 (s, 1H), 6.94 (d, 1H, J=8.8 Hz), 6.78 (d, 1H, J=8.8 Hz),
3.84 (s, 3H, CH3), 3.10-2.90 (m, 1H, CH2), 2.10-2.95 (m, 1H, CH2),
2.16 (s, 3H, CH3), 0.50 (t, 3H, J=7.3 Hz, CH3) ppm. 13C NMR (CDCl3,
100 MHz): δ=155.4 (s, Cq), 149.0 (s, Cq), 143.8 (s, Cq), 131.9 (s, Cq),
131.7 (s, Cq), 130.0 (d, CH), 129.6 (d, CH), 129.4 (d, CH), 125.5 (d,
CH), 123.2 (d, CH), 118.4 (d, CH), 116.1 (s, Cq), 116.0 (d, CH), 112.8
(d, CH), 112.0 (d, CH), 55.7 (q, CH3), 40.3 (s, Cq), 35.7 (t, CH2), 31.6
(q, CH3), 10.5 (q, CH3) ppm. HR-MS (ESI+) m/z calculated for
[C22H22N]+=[M+H]+: 305.1536; found 305.1537.
9-ethyl-9-methyl-10-phenyl-9,10-dihydroacridine (22bb):
This compound was prepared according to the GP-3 and isolated as
brown color solid 71% yield (106 mg): mp: 84-86
(petroleum ether/ethyl acetate 9:1, Rf(23b)=0.50, Rf(22bb)=0.70,
UV detection]. IR (MIR-ATR, 4000–600 cm-1):
max=2962, 1589,
°C; [TLC
9,10-dimethoxy-12,12-dimethyl-12H-benzo[a]xanthene (21fb):
ν
1
1476, 1334, 1268, 1164, 1028, 907, 743, 699 cm-1. H NMR (CDCl3,
400 MHz): δ=7.62 (dd, 2H, J=7.3 and 7.8 Hz), 7.49 (dd, 1H, J=7.3 and
7.8 Hz), 7.37 (d, 2H, J=7.8 Hz), 7.30 (d, 2H, J=8.3 Hz), 6.94 (dd, 2H,
J=7.3 and 8.8 Hz), 6.89 (dd, 2H, J=7.3 and 8.8 Hz), 6.19 (d, 2H, J=8.3
Hz), 1.93 (q, 2H, J=7.3 Hz, CH2), 1.77 (s, 3H, CH3), 0.70 (t, 3H, J=7.3
Hz, CH3) ppm. 13C NMR (CDCl3, 100 MHz): δ=141.5 (s, 2C, Cq), 141.3
(s, Cq), 131.3 (d, 2C, CH), 130.9 (d, 2C, CH), 128.1 (d, CH), 127.6 (s,
Cq), 126.3 (d, 2C, CH), 126.1 (d, 2C, CH), 120.1 (d, 2C, CH), 113.8 (d,
2C, CH), 40.1 (s, Cq), 38.6 (t, CH2), 30.5 (q, CH3), 9.5 (q, CH3) ppm.
HR-MS (ESI+) m/z calculated for [C22H22N]+=[M+H]+: 300.1747;
found 300.1737.
This compound was prepared according to the GP-3 and isolated as
brown color solid 90% yield (127 mg): mp: 68-70
(petroleum ether/ethyl acetate 8:2, Rf(23f)=0.40, Rf(21fb)=0.60, UV
detection]. IR (MIR-ATR, 4000–600 cm-1):
max=2933, 1629, 1510,
°C; [TLC
ν
1402, 1339, 1241, 1150, 1078, 998, 815, 750, 668 cm-1. 1H NMR
(CDCl3, 400 MHz): δ=8.42 (d, 1H, J=8.8 Hz), 7.78 (d, 1H, J=7.8 Hz),
7.67 (d, 1H, J=8.8 Hz), 7.48 (dd, 1H, J=7.3 and 8.8 Hz), 7.35 (dd, 1H,
J=7.8 and 7.8 Hz), 7.14 (d, 1H, J=8.8 Hz), 6.92 (s, 1H), 6.54 (s, 1H),
3.92 (s, 3H, CH3), 3.89 (s, 3H, CH3), 2.10 (s, 6H, CH3) ppm. 13C NMR
(CDCl3, 100 MHz): δ=148.4 (s, Cq), 147.5 (s, Cq), 145.2 (s, Cq), 131.9
(s, 2C, Cq), 129.6 (d, CH), 129.3 (d, CH), 126.0 (d, CH), 125.6 (d, CH),
123.2 (d, CH), 122.3 (s, Cq), 119.3 (s, Cq), 118.4 (d, CH), 110.3 (d, CH),
99.2 (d, CH), 56.6 (q, CH3), 56.0 (q, CH3), 34.6 (s, Cq), 32.2 [q, 2C,
CH3) ppm. HR-MS (ESI+) m/z calculated for [C21H21O3]+=[M+H]+:
321.1485; found 321.1487.
2-methoxy-9,9-dimethyl-10-phenyl-9,10-dihydroacridine (22db):
This compound was prepared according to the GP-3 and isolated as
pale yellow color viscous liquid 80% yield (126 mg): [TLC (petroleum
ether/ethyl acetate 9:1, Rf(23d)=0.40, Rf(22db)=0.60, UV detection].
IR (MIR-ATR, 4000–600 cm-1):
νmax=2967, 1591, 1474, 1329, 1297,
12-ethyl-9,10-dimethoxy-12-methyl-12H-benzo[a]xanthene
(21gb):
1208, 1046, 872, 801, 747, 700, 639 cm-1. 1H NMR (CDCl3, 400 MHz):
δ=7.62 (dd, 2H, J=7.8 and 7.8 Hz), 7.49 (dd, 1H, J=7.3 and 7.3 Hz),
7.44 (d, 1H, J=7.8 Hz), 7.34 (d, 2H, J=7.3 Hz), 7.04 (s, 1H), 6.96 (dd,
1H, J=7.3 and 7.8 Hz), 6.90 (dd, 1H, J=7.3 and 7.3 Hz), 6.55 (d, 1H,
J=8.8 Hz), 6.26 (d, 1H, J=8.3 Hz), 6.20 (d, 1H, J=8.8 Hz), 3.77 (s, 3H,
CH3), 1.69 (s, 6H, CH3) ppm. 13C NMR (CDCl3, 100 MHz): δ=154.1 (s,
Cq), 141.6 (s, Cq), 141.3 (s, Cq), 135.5 (s, Cq), 131.5 (s, Cq), 131.4 (d,
This compound was prepared according to the GP-3 and isolated as
pale yellow color solid 78% yield (129 mg): mp: 93-95
°C; [TLC
(petroleum ether/ethyl acetate 8:2, Rf(23g)=0.40, Rf(21gb)=0.60, UV
detection]. IR (MIR-ATR, 4000–600 cm-1):
νmax=2963, 1592, 1474,
1312, 1211, 1039, 933, 879, 746, 699 cm-1. 1H NMR (CDCl3, 400
MHz): δ=8.44 (d, 1H, J=8.8 Hz), 7.78 (d, 1H, J=6.8 Hz), 7.67 (d, 1H,
8 | J. Name., 2012, 00, 1-3
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ARTICLE
2C, CH), 130.8 (d, 2C, CH), 129.2 (s, Cq), 128.1 (d, CH), 126.4 (d, CH), 126.3 (d, CH), 125.0 (d, CH), 122.4 (s, Cq), 120.4 (d, CH), 113.9 (d,
125.1 (d, CH), 120.1 (d, CH), 114.7 (d, CH), 113.7 (d, CH), 111.6 (d, CH), 105.2 (d, CH), 100.7 (t, CH2), 96.5 (d, CH), 36.1 (s, Cq), 31.1 (q,
CH), 111.0 (d, CH), 55.7 (q, CH3), 36.3 (s, Cq), 30.9 (q, 2C, CH3) ppm. 2C,
CH3)
ppm. HR-MS
(ESI+) m/z
calculated
for
HR-MS (ESI+) m/z calculated for [C22H22NO]+=[M+H]+: 316.1696; [C22H20NO2]+=[M+H]+: 330.1489; found 330.1484.
found 316.1682.
9-ethyl-2-methoxy-9-methyl-10-phenyl-9,10-dihydroacridine
Acknowledgement:
(22eb): This compound was prepared according to the GP-3 and
We are grateful to the Department of Science and Technology-
Science and Engineering Research Board (DST-SERB)
isolated as black color solid 81% yield (132 mg): mp: 112-114 °C;
[TLC (petroleum ether/ethyl acetate 9:1, Rf(23e)=0.40,
Rf(22eb)=0.70, UV detection]. IR (MIR-ATR, 4000–600 cm-1):
[NO.:SB/S1/OC-39/2014], New Delhi, for the financial support. L. M.
thank CSIR, New Delhi, for the award of research fellowship.
ν
max=2961, 1589, 1477, 1332, 1269, 1174, 1047, 908, 800, 746, 699
1
cm-1. H NMR (CDCl3, 400 MHz): δ=7.61 (dd, 2H, J=7.3 and 7.8 Hz),
7.49 (dd, 1H, J=6.8 and 7.8 Hz), 7.36 (d, 1H, J=7.8 Hz), 7.30 (d, 2H,
J=8.3 Hz), 6.98 (s, 1H), 6.94 (dd, 1H, J=6.8 and 8.3 Hz), 6.87 (dd, 1H,
J=7.3 and 7.3 Hz), 6.53 (d, 1H, J=7.3 Hz), 6.19 (d, 1H, J=8.3 Hz), 6.14
(d, 1H, J=7.8 Hz), 3.77 (s, 3H, CH3), 1.94 (q, 2H, J=7.3 and 7.8 Hz,
CH2), 1.78 (s, 3H, CH3), 0.72 (t, 3H, J=7.3 Hz, CH3) ppm. 13C NMR
(CDCl3, 100 MHz): δ=153.7 (s, Cq), 141.7 (s, 2C, Cq), 136.1 (s, Cq),
131.4 (d, 2C, Cq), 130.8 (d, 2C, Cq), 129.1 (d, 2C, CH), 128.0 (d, CH),
126.7 (s, Cq), 126.3 (d, CH), 126.1 (d, CH), 119.7 (d, CH), 114.5 (d,
CH), 113.5 (d, CH), 112.5 (d, CH), 111.1 (d, CH), 55.6 (q, CH3), 40.4
(s, Cq), 38.3 (t, CH2), 30.2 (q, CH3), 9.5 (q, CH3) ppm. HR-MS (ESI+)
m/z calculated for [C23H24NO]+=[M+H]+: 330.1852; found 330.1857.
2,3-dimethoxy-9,9-dimethyl-10-phenyl-9,10-dihydroacridine
(22fb): This compound was prepared according to the GP-3 and
Notes and References:
a.Dr. G. Satyanarayana
b.Department of Chemistry, Indian Institute of Technology Hyderabad, Kandi – 502
285, Sangareddy, Telangana, INDIA
c. Phone: (040) 2301 6033; Fax: (040) 2301 6003/32
d.E-mail: gvsatya@iith.ac.in
Electronic Supplementary Information (ESI) available: Experimental details and
NMR spectra. See DOI:
1) (a) K. Okuma, A. Nojima, N. Matsunaga and K. Shioji,
Org. Lett. 2009, 11, 169; (b) H. Yoshida, M.
Watanabe, H. Fukushima, J. Ohshita and A. Kunai,
Org. Lett. 2004, 6, 4049; (c) A. Pinter and M.
Klussmanna, Adv. Synth. Catal. 2012, 354, 701; (d) A.
Pinter, A. Sud, D. Sureshkumar and M. Klussmann,
Angew. Chem. 2010, 122, 5124; Angew. Chem. Int.
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isolated as black color solid 81% yield (139 mg): mp: 80-82
(petroleum ether/ethyl acetate 8:2, Rf(23f)=0.50, Rf(22fb)=0.30, UV
detection]. IR (MIR-ATR, 4000–600 cm-1):
max=2955, 2930, 1590,
°C; [TLC
ν
1
1444, 1311, 1239, 1154, 1082, 877, 747, 607 cm-1. H NMR (CDCl3,
400 MHz): δ=7.62 (dd, 2H, J=7.8 and 7.8 Hz), 7.50 (dd, 1H, J=7.3 and
8.8 Hz), 7.43 (d, 1H, J=7.3 Hz), 7.34 (d, 2H, J=7.3 Hz), 7.00 (s, 1H),
6.95 (dd, 1H, J=7.3 and 7.8 Hz), 6.89 (dd, 1H, J=6.8 and 7.8 Hz), 6.24
(d, 1H, J=7.8 Hz), 5.84 (s, 1H), 3.88 (s, 3H, CH3), 3.53 (s, 3H, CH3),
1.68 (s, 6H, CH3) ppm. 13C NMR (CDCl3, 100 MHz): δ=147.5 (s, Cq),
143.3 (s, Cq), 141.4 (s, Cq), 141.0 (s, Cq), 135.3 (s, Cq), 131.3 (d, Cq),
130.8 (d, 3C, CH), 129.4 (s, Cq), 128.2 (d, CH), 126.2 (d, CH), 125.2 (d,
CH), 121.3 (s, Cq), 120.2 (d, CH), 113.9 (d, CH), 110.1 (d, CH), 99.4 (d,
CH), 56.9 (q, CH3), 55.6 (q, CH3), 35.7 (s, Cq), 31.5 (q, 2C, CH3) ppm.
HR-MS (ESI+) m/z calculated for [C23H24NO2]+=[M+H]+: 346.1802;
found 346.1795.
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10,10-dimethyl-5-phenyl-5,10-dihydro-[1,3]dioxolo[4,5-b]acridine
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isolated as white color solid 79% yield (130 mg): mp: 188-190 °C;
[TLC (petroleum ether/ethyl acetate 8:2, Rf(23h)=0.50,
Rf(22hb)=0.70, UV detection]. IR (MIR-ATR, 4000–600 cm-1):
ν
max=2965, 2882, 1592, 1475, 1313, 1224, 1172, 1040, 934, 879,
747, 700, 610 cm-1. 1H NMR (CDCl3, 400 MHz): δ=7.59 (dd, 2H, J=6.6
and 8.0 Hz), 7.48 (dd, 1H, J=7.4 and 7.4 Hz), 7.42 (d, 1H, J=7.5 Hz),
7.31 (d, 2H, J=6.8 Hz), 6.96 (s, 1H), 6.92 (dd, 1H, J=8.0 and 5.4 Hz),
6.90 (dd, 1H, J=7.4 and 7.3 Hz), 6.25 (d, 1H, J=8.0 Hz), 5.87 (s, 1H),
5.81 (s, 2H, CH2) 1.64 (s, 6H, CH3) ppm. 13C NMR (CDCl3, 100 MHz):
δ=145.8 (s, Cq), 141.7 (s, Cq), 141.5 (s, Cq), 141.1 (s, Cq), 136.2 (s, Cq),
131.3 (d, 2C, CH), 130.9 (d, 2C, CH), 129.3 (s, Cq), 128.3 (d, CH),
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Copper Catalyzed Coupling of Protecting Group Free and Sterically Hindered 2-
Bromobenzyl Tertiary Alcohols with Phenols and Anilines: Facile Synthesis of
Xanthenes and Dihydroacridines
Lodi Mahendar and Gedu Satyanarayana
Department of Chemistry, Indian Institute of Technology Hyderabad, Kandi – 502 285, Sangareddy,
Telangana, INDIA
Phone: (040) 2301 6033; Fax: (040) 2301 6003/32
E-mail: gvsatya@iith.ac.in