Efficient one-pot synthesis of some new xanthene derivatives based on the reaction of dimedone with α, α ′-Bis(substituted-benzylidene) cycloalkanones using catalytic amount of pTSA

Article abstract of DOI:10.1080/00397911.2011.627104

A one-pot synthesis of a series of new xanthene derivatives has been achieved for the first time based on an application of Michael reaction between dimedone (5,5-dimethylcyclohexan-1,3-dione) and α, α '-bis(substituted-benzylidene)cycloalkanones using catalytic amount of p-toluene sulfonic acid as catalyst. The xanthenes were achieved efficiently via intramolecular cyclization of the Michael adduct.

Full text of DOI:10.1080/00397911.2011.627104

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Efficient One-Pot Synthesis of Some
New Xanthene Derivatives Based
on the Reaction of Dimedone with
α,α′-Bis(substituted-benzylidene)
Cycloalkanones Using Catalytic Amount
of pTSA
Zahed Karimi-Jaberi a & Baharak Pooladian a
a Department of Chemistry, Firoozabad Branch, Islamic Azad
University, Firoozabad, Fars, Iran
Accepted author version posted online: 14 Mar 2012.Version of
record first published: 21 Feb 2013.
To cite this article: Zahed Karimi-Jaberi & Baharak Pooladian (2013): Efficient One-Pot Synthesis
of Some New Xanthene Derivatives Based on the Reaction of Dimedone with α,α′-Bis(substituted-
benzylidene) Cycloalkanones Using Catalytic Amount of pTSA, Synthetic Communications: An
International Journal for Rapid Communication of Synthetic Organic Chemistry, 43:8, 1188-1199
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Synthetic Communications1, 43: 1188–1199, 2013
Copyright # Taylor & Francis Group, LLC
ISSN: 0039-7911 print=1532-2432 online
DOI: 10.1080/00397911.2011.627104
EFFICIENT ONE-POT SYNTHESIS OF SOME NEW
XANTHENE DERIVATIVES BASED ON THE REACTION
OF DIMEDONE WITH a,a’-BIS(SUBSTITUTED-
BENZYLIDENE) CYCLOALKANONES USING
CATALYTIC AMOUNT OF TSA
P
Zahed Karimi-Jaberi and Baharak Pooladian
Department of Chemistry, Firoozabad Branch, Islamic Azad University,
Firoozabad, Fars, Iran
GRAPHICAL ABSTRACT
Abstract A one-pot synthesis of a series of new xanthene derivatives has been achieved
for the first time based on an application of Michael reaction between dimedone
(5,5-dimethylcyclohexan-1,3-dione) and a,a ’-bis(substituted-benzylidene)cycloalkanones
using catalytic amount of p-toluene sulfonic acid as catalyst. The xanthenes were achieved
efficiently via intramolecular cyclization of the Michael adduct.
Keywords a,a0-Bis(substituted-benzylidene)cycloalkanones; dimedone; Michael addition;
p-toluenesulfonic acid; xanthenes
INTRODUCTION
Xanthenes and benzoxanthenes are important heterocycles that are known to
possess multiple biological activities. Although not widely found in nature,
xanthenes and compounds based on these core templates exhibit a broad spectrum
of pharmaceutical activities such as antibacterial,[1] anti-inflammatory,[2] and
antiviral[3] activities. In addition, these compounds have been employed as dyes[4]
and pH-sensitive fluorescent materials for visualization of biomolecular assemblies[5]
and utilized in laser technologies.[6] Therefore, the synthesis of various xanthene
Received June 24, 2011.
Address correspondence to Zahed Karimi-Jaberi, Department of Chemistry, Firoozabad Branch,
Islamic Azad University, P.O. Box 74715-117 Firoozabad, Fars, Iran. E-mail: z.karimi@iauf.ac.ir
1188

NEW XANTHENE DERIVATIVES
1189
Scheme 1. Reaction of a,a0-bis(substituted-benzylidene) cycloalkanones (1) with dimedone.
derivatives is of great importance. A broad utility range has made xanthenes prime
synthetic candidates, thereby accentuating the need to develop newer synthetic
routes for scaffold manipulation of xanthene derivatives.
The a,a0-bis(substituted-benzylidene)cycloalkanones are very important
materials used commonly as precursors of some important organic compounds.
2-Amino-3-cyano-4H-pyran derivatives were synthesized by one-step reaction of
bisarylidenecycloalkanones with malononitrile.[7] Also, bisbenzylidenecyclohexa-
none derivatives have been efficiently used as trapping dipolarophiles for the syn-
thesis of several spiro[pyrrolidine2,30-oxindole] derivatives.[8] In 2005, Ahmed et al.
reported synthesis of the fused spiroketal skeleton by an application of Michael reac-
tion between dimedone and diarylideneacetone using anhydrous ZnCl2 as catalyst.[9]
Herein we report the reaction of dimedone with a,a ’-bis(substituted-benzylidene)
cycloalkanones for the synthesis of xanthene derivatives using p-toluene sulfonic acid
(pTSA) as catalyst for the first time (Scheme 1).
The use of solid acid catalysts has gained vast importance in organic synthesis
because of their several advantages such as operationally simplicity, nontoxicity,
reusability, low cost, and easy isolation after completion of the reaction. In recent
years pTSA has been considered as an efficient, inexpensive, and readily available
catalyst for several organic transformations.[10]
RESULTS AND DISCUSSION
Initially, the reaction of a,a0-bis benzylidene cyclohexanone (1) with dimedone
(2) was used as a model reaction. Reactions at different conditions and various
molar ratios of substrates in the presence of pTSA revealed that acceptable yield
(80%) of the desired product (3j) was obtained in toluene under reflux conditions
after 6 h and a molar ratio of a,a0-bis benzylidene cyclohexanone=dimedone=pTSA
of 1:1.2:0.15. After completion of the reaction, the catalyst (pTSA) can be separated
from the reaction mixture by extraction with water.
We then investigated the reaction scope of this catalytic system and its toler-
ance of functional groups in the case of other a,a0-bis(substituted-benzylidene)
cycloalkanones. Under the optimized reaction conditions, a wide range of a,a0-bis
(substituted-benzylidene)cycloalkanones were investigated, and the results are shown

1190
Z. KARIMI-JABERI AND B. POOLADIAN
Table 1. Synthesis of new xanthene derivatives (3a–w) under reflux in toluenea
Entry
Z
R
Product
Time (h)
Yield (%)b
Mp (ꢀC)
1
2
CH2
CH2
H
4-Me
4-OMe
3- OMe
4-Cl
3a
3b
3c
3d
3e
3f
5
4
85
87
92
87
90
83
85
80
78
80
83
85
90
75
75
85
85
75
80
78
75
80
75
204–206
230–232
174–176
159–161
233–234
235–237
223–226
250–252
198–199
166–168
165–167
158–160
156–159
165–167
149–152
176–179
175–178
145–146
191–192
161–163
159–161
223–225
169–171
3
CH2
CH2
6
4
9
5
CH2
CH2
7
6
2-Cl
5
7
CH2
CH2
2,4-Cl2
4-Br
4-F
3g
3h
3i
4
8
5
9
CH2
3
10
11
12
13
14
15
16
17
18
19
20
21
22
23
CH2-CH2
CH2-CH2
CH2-CH2
CH2-CH2
CH2-CH2
CH2-CH2
CH2-CH2
CH2-CH2
CH(CH3)CH2
CH(CH3)CH2
CH(CH3)CH2
CH(CH3)CH2
CH(CH3)CH2
CH(CH3)CH2
H
3j
6
4-Me
4-OMe
4-Cl
3k
3l
6
6
3m
3n
3o
3p
3q
3r
3s
3t
9
4-Br
4-F
9
4
3-NO2
4-NO2
H
12
15
8
4-Me
4-OMe
4-Cl
8
5
3u
3v
3w
13
11
5
2-Cl
4-F
aReaction conditions: a,a0-bis(substituted-benzylidene) cycloalkanones
(2.4 mmol), pTSA (0.3 mmol, 15 mol %), toluene (15 mL), reflux.
bIsolated yields.
1 (2 mmol), dimedone 2
Scheme 2. Proposed mechanism.

NEW XANTHENE DERIVATIVES
1191
in Table 1. In all these cases, the corresponding xanthene derivatives were obtained
in good yields. The results (Table 1) indicated that substrates 1 bearing both
electron-donating groups and electron-withdrawing groups can be involved in this
reaction to afford desired products 3 with good yields. It is concluded that the
electronic nature of the substituents has no significant effect on this reaction. It is
important to note that the synthesis of desired products could not be achieved in
the absence of catalyst (pTSA).
The mechanism of this reaction is believed to involve Michael addition of
dimedone with a,a0-bis(substituted-benzylidene)cycloalkanones in the presence of
pTSA. The acid catalyst (pTSA) activated the carbonyl group of the proposed inter-
mediate 5, which presumably underwent cyclization to form xanthene derivatives,
accompanied by loss of H2O as shown in Scheme 2 (4!5!6!3)[9]
The structures of all products 3a–w were confirmed by infrared (IR), 1H NMR,
13C NMR, and elemental analysis.
CONCLUSION
In conclusion, this article describes an efficient method for the reaction of
dimedone with a,a0-bis(substituted-benzylidene)cycloalkanones using a catalytic
amount of pTSA as catalyst under reflux in toluene. Thus a series of new xanthene
derivatives were synthesized in good yields.
EXPERIMENTAL
a,a0-Bis(substituted-benzylidene)cycloalkanones have been synthesized
through cross-aldol condensation of cycloalkanones and aldehydes using our
reported method.[11]
General Procedure for the Synthesis of New Xanthene
Derivatives (3a–w)
A mixture of a,a0-bis(substituted-benzylidene)cycloalkanones 1 (2 mmol),
dimedone 2 (2.4 mmol), and 15 mol% pTSA (0.3 mmol) in dry toluene (15 mL) was
refluxed for the appropriate time indicated in Table 1. After completion of the reac-
tion, as indicated by thin-layer chromatography (TLC, ethyl acetate = n-hexane 1=4),
the reaction mixture was allowed to cool at room temperature. Water (10 ml) was
added (to dissolve the catalyst) and then extracted. The toluene extract was dried
over anhydrous sodium sulfate and evaporated in vacuo. The crude product was
purified by recrystallization from ethanol to afford pure products.
3-Benzylidene-6,6-dimethyl-9-phenyl-2,3,6,7-tetrahydrocyclopenta
[b]chromen-8(1H,5H,9H)-one (Entry 1, 3a)
White powder, IR (KBr): 3026, 2957, 1663, 1617, 1450, 1369, 1212, 696 cmꢁ1
;
1H NMR (400 MHz, CDCl3): d ¼ 1.12 (s, 3H, CH3), 1.17 (s, 3H, CH3), 2.23–2.32
(m, 3H, CH2, CH), 2.38–2.44 (m, 1H, CH), 2.63 (dd, 2H, J ¼ 17.2, 17.2 Hz, CH2),
=
2.82–2.96 (m, 2H, CH2), 4.50 (s, 1H, CH), 6.52 (s, 1H, CH), 7.20–7.24 (m, 2H,

1192
Z. KARIMI-JABERI AND B. POOLADIAN
ArH), 7.29–7.30 (m, 4H, ArH), 7.35–7.43 (m, 4H, ArH); 13C NMR (100 MHz,
CDCl3): d ¼ 27.11, 27.78, 28.17, 28.98, 32.18, 38.58, 41.71, 51.07, 112.72, 116.70,
125.17, 126.27, 126.56, 127.84, 128.10, 128.15, 128.34, 128.50, 137.71, 137.74,
143.39, 164.97 and 197.47. Anal. calcd. for C27H26O2: C, 84.78; H, 6.58. Found: C,
84.52; H, 6.40.
3-(4-Methylbenzylidene)-9-(4-methylphenyl)-6,6-dimethyl-2,3,6,7-
tetrahydrocyclopenta[b]chromen- 8(1H,5H,9H)-one (Entry2, 3b)
1
White powder, IR (KBr): 2923, 1659, 1617, 1370, 1047, 876 cmꢁ1; H NMR
(400 MHz, CDCl3): d ¼ 1.12 (s, 3H, CH3), 1.16 (s, 3H, CH3), 2.23–2.27 (m, 3H,
CH2, CH), 2.28–2.32 (m, 1H, CH), 2.33 (s, 3H, CH3), 2.38 (s, 3H, CH3), 2.62 (dd,
2H, J ¼ 17.6, 17.6 Hz, CH2), 2.80–2.95 (m, 2H, CH2), 4.47 (s, 1H, CH), 6.50 (s, 1H,
=
CH), 7.11 (d, 2H, J ¼ 7.6 Hz, ArH), 7.16–7.20 (m, 4H, ArH), 7.33 (d, 2H, J ¼ 7.6 Hz,
Hz, ArH); 13CNMR (100 MHz, CDCl3): d ¼ 21.11, 21.23, 27.09, 27.80, 28.17, 28.99,
32.18, 38.15, 41.72, 51.10, 112.86, 116.45, 124.82, 127.98, 128.08, 129.06 129.24,
134.94, 136.01, 136.02, 136.85, 140.53, 146.74, 164.87, and 197.52. Anal. calcd. for
C29H30O2: C, 84.84; H, 7.37. Found: C, 84.91; H, 7.40.
3-(4-Methoxybenzylidene)-9-(4-methoxyphenyl)-6,6-dimethyl-2,3,6,
7-tetrahydrocyclopenta[b]chromen-8(1H,5H,9H)-one (Entry 3, 3c)
White crystals, IR (KBr): 2956, 1661, 1616, 1509, 1369, 1250, 1175, 1037,
1
750 cmꢁ1; H NMR (400 MHz, CDCl3): d ¼ 1.10 (s, 3H, CH3), 1.15 (s, 3H, CH3),
2.21–2.30 (m, 3H, CH2, CH), 2.35–2.42 (m, 1H, CH), 2.60 (dd, 2H, J ¼ 17.2,
17.2 Hz, CH2), 2.83–2.88 (m, 2H, CH2), 3.79 (s, 3H, OCH3), 3.84 (s, 3H, OCH3),
=
4.44 (s, 1H, CH), 6.46 (s, 1H, CH), 6.83 (d, 2H, J ¼ 8.8 Hz, ArH), 6.92 (d, 2H,
J ¼ 8.4 Hz, ArH), 7.19 (d, 2H, J ¼ 8.4 Hz, ArH), 7.36 (d, 2H, J ¼ 8.8 Hz, ArH);
13C NMR (100 MHz, CDCl3): d ¼ 26.97, 27.77, 28.10, 28.98, 32.18, 37.61, 41.69,
51.09, 55.20, 55.30, 112.97, 113.68, 113.98, 115.98, 124.20, 129.07, 129.35, 130.58,
135.58, 135.79, 146.77, 158.03, 158.15, 164.76 and 197.64. Anal. calcd. for
C29H30O4: C, 78.71; H, 6.83. Found: C, 78.91; H, 6.90.
3-(3-Methoxybenzylidene)-9-(2-methoxyphenyl)-6,6-dimethyl-2,3,6,
7-tetrahydrocyclopenta[b]chromen-8(1H,5H,9H)-one (Entry 4, 3d)
White crystals, IR (KBr): 2956, 2835, 1663, 1617, 1598, 1369, 1243, 1047, 885,
1
778, 693 cmꢁ1; H NMR (400 MHz, CDCl3): d ¼ 1.13 (s, 3H, CH3), 1.16 (s, 3H,
CH3), 2.26–2.32 (m, 3H, CH2, CH), 2.34–2.39 (m, 1H, CH), 2.62 (dd, 2H,
J ¼ 17.6, 17.2 Hz, CH2), 2.86–2.91 (m, 2H, CH2), 3.80 (s, 3H, OCH3), 3.85 (s, 3H,
=
OCH3), 4.47 (s, 1H, CH), 6.48 (s, 1H, CH), 6.73–6.81 (m, 2H, CH, ArH), 6.82
(s, 1H, ArH), 6.87 (d, 1H, J ¼ 7.6 Hz, ArH) 6.96 (s, 1H, ArH), 7.02 (d, 1H, J ¼ 8 Hz,
Hz, ArH), 7.21 (t, 1H, J ¼ 8 Hz, ArH),7.29 (t, 1H, J ¼ 8 Hz, ArH); 13C NMR
(100 MHz, CDCl3): d ¼ 27.13, 27.84, 28.20, 28.97, 32.18, 38.59, 41.69, 51.06, 55.17,
55.21, 111.66, 111.75, 112.52, 113.68, 114.06, 116.63, 120.59, 120.87, 125.29,
129.26, 129.42, 138.11, 139.09, 145.07, 146.67, 159.64, 159.66, 165.06 and 197.50.
Anal. calcd. for C29H30O4: C, 78.71; H, 6.83. Found: C, 78.99; H, 6.94.

NEW XANTHENE DERIVATIVES
1193
3-(4-Chlorobenzylidene)-9-(4-chlorophenyl)-6,6-dimethyl-2,3,5,
6-tetrahydrocyclopenta[b]chromen-7(1H, 8H, 9H)-one (Entry 5, 3e)
White powder, IR (KBr): 2959, 2926, 1654, 1616, 1489, 1370, 1090, 846 cmꢁ1
;
1H NMR (400 MHz, CDCl3): d ¼ 1.10 (s, 3H, CH3), 1.16 (s, 3H, CH3), 2.21–2.31 (m,
3H, CH2, CH), 2.34–2.44 (m, 1H, CH), 2.60 (dd, 2H, J ¼ 18.4, 18.4 Hz, CH2),
=
2.82–2.88 (m, 2H, CH2), 4.47 (s, 1H, CH), 6.47 (s, 1H, CH), 7.20–7.33 (m, 10H,
ArH); 13C NMR (100 MHz, CDCl3): d ¼ 27.03, 27.73, 28.11, 28.95, 32.21, 38.04,
41.46, 50.99, 112.41, 115.87, 124.99, 128.54, 128.69, 129.29, 131.88, 132.32, 136.05,
138.02, 141.81, 146.92, 165.04 and 197.47. Anal. calcd. for C27H24Cl2O2: C, 71.84;
H, 5.36. Found: C, 71.94; H, 5.10.
3-(2-Chlorobenzylidene)-9-(2-chlorophenyl)-6,6-dimethyl-2,3,6,
7-tetrahydrocyclopenta[b]chromen-8(1H,5H,9H)-one (Entry 6, 3f)
White powder, IR (KBr): 2941, 2920, 1656, 1616, 1439, 1372, 1048, 753 cmꢁ1
;
1H NMR (400 MHz, CDCl3): d ¼ 1.15 (s, 3H, CH3), 1.17 (s, 3H, CH3), 2.18–2.24 (m,
1H, CH), 2.28–2.29 (m, 2H, CH2), 2.48–2.54 (m, 1H, CH), 2.61–2.68 (m, 2H, CH2),
=
2.76–2.78 (m, 1H, CH), 2.82–2.85 (m, 1H, CH), 5.08 (s, 1H, CH), 6.83 (s, 1H, CH),
7.11–7.35 (m, 5H, ArH), 7.36 (d, 1H, J ¼ 7.6 Hz, ArH), 7.42 (dd, 1H, J ¼ 1.6, 1.2 Hz,
ArH), 7.51 (dd, 1H, J ¼ 1.6, 1.6 Hz, ArH); 13C NMR (100 MHz, CDCl3): d ¼ 26.67,
27.89, 27.97, 28.94, 32.21, 35.31, 41.67, 50.97, 111.90, 112.98, 125.45, 126.55, 127.09,
127.46, 127.74, 128.42, 129.50, 129.76, 130, 133.45, 133.56, 135.39, 139.54, 140.71,
146.76, 166.01 and 197.16. Anal. calcd. for C27H24Cl2O2: C, 71.84; H, 5.36. Found:
C, 71.90; H, 5.40.
3-(2,4-Dichlorobenzylidene)-9-(2,4-dichlorophenyl)-6,6-dimethyl-2,3,
6,7-tetrahydrocyclopenta[b]chromen-8(1H,5H,9H)-one (Entry 7, 3g)
White powder, IR (KBr): 2923, 2853, 1657,1616, 1467, 1373, 1046, 868, 807,
1
657 cmꢁ1; H NMR (400 MHz, CDCl3): d ¼ 1.15 (s, 3H, CH3), 1.16 (s, 3H, CH3),
2.16–2.32 (m, 3H, CH2, CH), 2.45–2.51 (m, 1H, CH), 2.59–2.85 (m, 4H, CH2,
=
CH2), 5.0 (s, 1H, CH), 6.74 (s, 1H, CH), 7.08–7.23 (m, 3H, ArH), 7.37–7.43 (m,
3H, ArH); 13C NMR (100 MHz, CDCl3): d ¼ 26.65, 27.84, 27.93, 28.40, 28.88,
32.21, 41.62, 50.90, 111.54, 112.29, 126.90, 127.47, 128.98, 129.10, 129.27, 129.35,
129.55, 132.13, 132.29, 132.37, 132.73, 133.86, 134.05, 134.11, 139.78, 166.12 and
197.12. Anal. calcd. for C27H22Cl4O2: C, 62.33; H, 4.26. Found: C, 62.29; H, 4.22.
3-(4-Bromobenzylidene)-9-(4-bromophenyl)-6,6-dimethyl-2,3,6,
7-tetrahydrocyclopenta[b]chromen-8(1H,5H,9H)-one (Entry 8, 3h)
Pale pink powder, IR (KBr): 2956, 2924, 1653, 1615, 1485, 1369, 1114, 1048,
843 cmꢁ1;1H NMR (400 MHz, CDCl3): d ¼ 1.10 (s, 3H, CH3), 1.15 (s, 3H, CH3),
2.20–2.24 (m, 4H, CH2, CH2), 2.55–2.65 (m, 2H, CH2), 2.77–2.85 (m, 2H, CH2),
=
4.46 (s, 1H, CH), 6.45 (s, 1H, CH), 7.09–7.20 (m, 2H, ArH), 7.26–7.32 (m, 2H,
ArH), 7.40–7.43 (m, 2H, ArH), 7.46–7.52 (m, 2H, ArH); 13C NMR (100 MHz,
CDCl3): d ¼ 27.05, 27.74, 28.12, 28.94, 32.20, 38.14, 41.64, 50.98, 112.34, 115.95,

1194
Z. KARIMI-JABERI AND B. POOLADIAN
120.03, 120.48, 125.01, 129.61, 129.87, 131.48, 131.63, 136.48, 138.19, 142.31, 146.96, 165.04
and 197.40. Anal. calcd. for C27H24Br2O2: C, 60.02; H, 4.48. Found: C, 60.09; H, 4.52.
3-(4-Fluorobenzylidene)-9-(4-fluorophenyl)-6,6-dimethyl-2,3,6,
7-tetrahydrocyclopenta[b]chromen-8(1H,5H,9H)-one (Entry 9, 3i)
White crystals, IR (KBr): 2927, 2827, 1662, 1618, 1506, 1369, 1218, 1156, 1047,
1
851 cmꢁ1; H NMR (400 MHz, CDCl3): d ¼ 1.10 (s, 3H, CH3), 1.16 (s, 3H, CH3),
2.22–2.31 (m, 3H, CH2, CH), 2.38–2.42 (m, 1H, CH), 2.56–2.65 (m, 2H, CH2),
=
2.86–2.88 (m, 2H, CH2), 4.48 (s, 1H, CH), 6.48 (s, 1H, CH), 6.95–7.08 (m, 4H,
ArH), 7.22–7.39 (m, 4H, ArH); 13C NMR (100 MHz, CDCl3): d ¼ 26.90, 27.72,
28.04, 28.94, 32.18, 37.80, 41.66, 51.03, 112.68, 115.05, 115.30 (d, J ¼ 36 Hz),
115.78, 124.64, 129.54 (d, J ¼ 24 Hz), 129.61 (d, J ¼ 20 Hz), 133.78 (d, J ¼ 12 Hz),
137.04 (d, J ¼ 8 Hz), 139.09 (d, J ¼ 12 Hz), 146.84, 160.19 (d, J ¼ 132 Hz), 162.63
(d, J ¼ 124 Hz), 164.90 and 197.48. Anal. calcd. for C27H24F2O2: C, 77.49; H, 5.78.
Found: C, 77.44; H, 5.75.
5-Benzylidene-3,3-dimethyl-9-phenyl-3,4,5,6,7,8-hexahydro-2H-
xanthen-1(9H)-one (Entry 10, 3j)
White powder, IR (KBr): 3026, 2929, 1662, 1627, 1491, 1451, 1379, 1223, 1142,
1
1062, 699 cmꢁ1; H NMR (400 MHz, CDCl3): d ¼ 1.05 (s, 3H, CH3), 1.15 (s, 3H,
CH3), 1.60–1.69 (m, 2H, CH2), 2.06–2.09 (m, 2H, CH2), 2.24 (dd, 2H, J ¼ 16.4,
16.4 Hz, CH2), 2.57 (s, 2H, CH2), 2.59–2.63 (m, 1H, CH), 2.73–2.75 (m, 1H, CH),
4.24 (s, 1H, CH), 6.98 (s, 1H, CH), 7.18–7.40 (m, 10H, ArH); 13C NMR
=
(100 MHz, CDCl3): d ¼ 22.45, 27.12, 27.42, 27.67, 29.34, 32.15, 40.32, 41.34, 50.83,
112.57, 118.22, 122.05, 126.56, 128.13, 128.25, 128.31, 129.25, 130.27, 137.40,
141.84, 144.15, 164 and 197.18. Anal. calcd. For C28H28O2: C, 84.81; H, 7.11.
Found: C, 84.57; H, 6.90.
5-(4-Methylbenzylidene)-9-(4-methylphenyl)-3,3-dimethyl-3,4,5,6,7,
8-hexahydro-2H-xanthen-1(9H)-one (Entry 11, 3k)
White powder, IR (KBr): 2955, 1661, 1627, 1510, 1377, 1220, 1141, 815 cmꢁ1
;
1H NMR (400 MHz, CDCl3): d ¼ 1.07 (s, 3H, CH3), 1.16 (s, 3H, CH3), 1.60–1.69 (m,
2H, CH2), 2.08 (t, 2H, J ¼ 6 Hz, CH2), 2.25 (dd, 2H, J ¼ 16.4, 16.4 Hz, CH2), 2.33 (s,
3H, CH3), 2.40 (s, 3H, CH3), 2.57 (s, 2H, CH2), 2.59–2.63 (m, 1H, CH), 2.73–2.79
=
(m, 1H, CH), 4.21 (s, 1H, CH), 6.96 (s, 1H, CH), 7.10–7.12 (m, 2H, ArH),
7.19–7.29 (m, 6H, ArH); 13C NMR (100 MHz, CDCl3): d ¼ 21.13, 21.26, 22.52,
27.22, 27.51, 27.68, 29.40, 32.20, 39.94, 41.39, 50.90, 112.70, 118.04, 121.89,
128.23, 128.91, 129.02, 129.24, 129.72, 134.56, 136, 136.36, 141.30, 141.82, 163.96
and 197.27. Anal. calcd. for C30H32O2: C, 84.87; H, 7.60. Found: C, 84.93; H, 7.64.
5-(4-Methoxybenzylidene)-9-(4-methoxyphenyl)-3,3-dimethyl3,4,5,6,
7,8-hexahydro-2H-xanthen-1(9H)-one (Entry 12, 3l)
White crystals, IR (KBr): 2932, 2834, 1660, 1626, 1509, 1377, 1250, 1174, 1036,
1
836 cmꢁ1; H NMR (400 MHz, CDCl3): d ¼ 1.05 (s, 3H, CH3), 1.14 (s, 3H, CH3),

NEW XANTHENE DERIVATIVES
1195
1.62–1.65 (m, 2H, CH2), 2.07 (t, 2H, J ¼ 6 Hz, CH2), 2.23 (dd, 2H, J ¼ 16.4, 16 Hz,
CH2), 2.55 (s, 2H, CH2), 2.57–2.63 (m, 1H, CH), 2.71–2.75 (m, 1H, CH), 3.79 (s, 3H,
OCH3), 3.85 (s, 3H, OCH3), 4.18 (s, 1H, CH), 6.82–6.85 (m, 2H, ArH), 6.92–6.93(m,
2H, ArH), 6.94 (s, 1H, CH), 7.23–7.25 (m, 2H, ArH), 7.28–7.30 (m, 2H, ArH); 13C
=
NMR (100 MHz, CDCl3): d ¼ 22.53, 27.22, 27.46, 27.63, 29.39, 32.19, 41.37, 50.88,
55.19, 55.30, 112.77, 113.64, 117.71, 121.48, 128.84, 129.28, 130, 130.55, 131.37,
136.53, 141.86, 158.18, 158.29, 163.91 and 197.39. Anal. calcd. for C30H32O4: C,
78.92; H, 7.06. Found: C, 78.65; H, 6.98.
5-(4-Chlorobenzylidene)-9-(4-chlorophenyl)-3,3-dimethyl-3,4,5,6,7,8-
hexahydro-2H-xanthen-1(9H)-one (Entry 13, 3m)
White powder, IR (KBr): 2957, 1662, 1627, 1488, 1377, 1222, 1061, 1014,
1
834 cmꢁ1; H NMR (400 MHz, CDCl3): d ¼ 1.04 (s, 3H, CH3), 1.15 (s, 3H, CH3),
1.58–1.74 (m, 2H, CH2), 1.98–2.12 (m, 2H, CH2), 2.24 (dd, 2H, J ¼ 16.4, 16 Hz,
CH2), 2.52–2.60 (m, 3H,CH2, CH), 2.68–2.76 (m, 1H, CH), 4.22 (s, 1H, CH), 6.92
(s, 1H, CH), 7.25–7.29 (m, 6H, ArH), 7.33–7.36 (m, 2H, ArH); 13C NMR(100 MHz,
=
CDCl3): d ¼ 22.35, 27.10, 27.41, 27.61, 29.35, 32.21, 39.82, 41.32, 50.79, 112.26,
118.09, 121.21, 128.38, 128.48, 129.70, 130.53, 130.63, 132.30, 132.41, 135.74,
141.94, 142.62, 164.07 and 197.15. Anal. calcd. for C28H26Cl2O2: C, 72.26; H, 5.63.
Found: C, 72.19; H, 5.59.
5-(4-Bromobenzylidene)-9-(4-bromophenyl)-3,3-dimethyl-3,4,5,6,7,8-
hexahydro-2H-xanthen-1(9H)-one (Entry 14, 3n)
Pale pink powder, IR (KBr): 2924, 2868, 1658, 1623, 1484, 1378, 1223, 831 cmꢁ1
;
1H NMR (400 MHz, CDCl3): d ¼ 1.04 (s, 3H, CH3), 1.15 (s, 3H, CH3), 1.62–1.64 (m,
2H, CH2), 1.99–2.09 (m, 2H, CH2), 2.24 (dd, 2H, J ¼ 16, 16.4 Hz, CH2), 2.50–2.60 (m,
=
3H, CH2, CH), 2.68–2.72 (m, 1H, CH), 4.20 (s, 1H, CH), 6.90 (s, 1H, CH), 7.19–7.21
(m, 4H, ArH), 7.40–7.42 (m, 2H, ArH), 7.49–7.51 (m, 2H, ArH); 13C NMR
(100 MHz, CDCl3): d ¼ 22.34, 27.11, 27.43, 27.62, 29.35, 32.21, 39.91, 41.32, 50.79,
112.18, 118.07, 120.47, 120.59, 121.27, 130.10, 130.71, 130.85, 131.33, 131.43,
136.19, 141.96, 143.13, 164.08 and 197.14. Anal. calcd. for C28H26Br2O2: C, 60.67;
H, 4.73. Found: C, 60.76; H, 4.80.
5-(4-Fluorobenzylidene)-9-(4-fluorophenyl)-3,3-dimethyl-3,4,5,6,7,8-
hexahydro-2H-xanthen-1(9H)-one (Entry 15, 4o)
White crystals, IR (KBr): 2957, 1662, 1628, 1506, 1378, 1222, 1157, 843 cmꢁ1
;
1H NMR (400 MHz, CDCl3): d ¼ 1.05 (s, 3H, CH3), 1.15 (s, 3H, CH3), 1.61–1.70
(m, 2H, CH2), 2.04–2.10 (m, 2H, CH2), 2.24 (dd, 2H, J ¼ 16, 16 Hz, CH2),
2.55–2.58 (m, 3H, CH2, CH), 2.68–2.73 (m, 1H, CH), 4.23 (s, 1H, CH), 6.93 (s, 1H,
=
CH), 6.98 (t, 2H, J ¼ 8.8 Hz, ArH), 7.07 (t, 2H, J ¼ 8.8 Hz, ArH), 7.27–7.32 (m,
4H, ArH); 13C NMR (100 MHz, CDCl3): d ¼ 22.40, 27.07, 27.39, 27.60, 29.34,
32.19, 39.59, 41.33, 50.38, 112.52, 115.0 (d, J ¼ 20 Hz), 115.22 (d, J ¼ 20 Hz),
117.97, 121.20, 129.75(d, J ¼ 36 Hz), 130.01, 130.83 (d, J ¼ 32 Hz), 133.35 (d,
J ¼ 12 Hz), 139.87 (d, J ¼ 12 Hz), 141.91, 160.35 (d, J ¼ 40 Hz), 162.79 (d, J ¼ 32 Hz),

1196
Z. KARIMI-JABERI AND B. POOLADIAN
163.98 and 197.21. Anal. calcd. for C28H26F2O2: C, 77.76; H, 6.06. Found: C, 77.85;
H, 7.02.
5-(3-Nitrobenzylidene)-3,3-dimethyl-9-(3-nitrophenyl)-3,4,5,6,7,8-
hexahydro-2H-xanthen-1(9H)-one (Entry 16, 3p)
Pale yellow powder, IR (KBr): 2957, 1661, 1627, 1528, 1378, 1349, 808, 734 cmꢁ1
;
1H NMR (400 MHz, CDCl3): d ¼ 1.06 (s, 3H, CH3), 1.18 (s, 3H, CH3), 1.66–1.73 (m,
2H, CH2), 1.99–2.07 (m, 1H, CH), 2.10–2.17 (m, 1H, CH), 2.25 (dd, 2H, J ¼ 16,
19.4 Hz, CH2), 2.56–2.66 (m, 3H, CH2, CH), 2.72–2.78 (m, 1H, CH), 4.39 (s, 1H,
=
CH), 7.03 (s, 1H, CH), 7.48 (t, 1H, J ¼ 8 Hz, ArH), 7.56 (t, 1H, J ¼ 8 Hz, ArH),
7.65 (d, 1H, J ¼ 7.6 Hz, ArH), 7.71 (d, 1H, J ¼ 7.6 Hz, ArH), 8.08–8.13 (m, 2H,
ArH), 8.15 (s, 1H, ArH), 8.20 (s, 1H, ArH); 13C NMR (100 MHz, CDCl3):
d ¼ 22.16, 29.97, 27.49, 27.63, 28.26, 29.26, 32.30, 40.37, 50.70, 111.59, 118.13,
120.78, 121.53, 122.01, 122.95, 123.90, 129.16, 129.21, 132.16, 134.79, 135.15, 138.84,
142.08, 146.08, 148.22, 148.57, 164.56 and 197.09. Anal. calcd. for C28H26N2O6 : C,
69.12; H, 5.39; N, 5.76. Found: C, 68.47; H, 5.35; N, 5.68.
5-(4-Nitrobenzylidene)-3,3-dimethyl-9-(4-nitrophenyl)-3,4,5,6,7,8-
hexahydro-2H-xanthen-1(9H)-one (Entry 17, 3q)
1
Yellow powder, IR (KBr): 2957, 1661, 1625, 1517, 1342, 856 cmꢁ1; H NMR
(400 MHz, CDCl3): d ¼ 1.04 (s, 3H, CH3), 1.17 (s, 3H, CH3), 1.64–1.74 (m, 2H,
CH2), 1.98–2.04 (m, 1H, CH), 2.19–2.32 (m, 3H, CH2, CH), 2.60–2.63 (m, 3H,
=
CH2, CH), 2.74–2.78 (m, 1H, CH), 4.39 (s, 1H, CH), 7.04 (s, 1H, CH), 7.49 (t,
4H, J ¼ 8.4 Hz, ArH), 8.17 (d, 2H, J ¼ 8,4 Hz, ArH), 8.24(d, 2H, J ¼ 8,4 Hz, ArH);
13C NMR(100 MHz, CDCl3): d ¼ 22.20, 27.21, 27.41, 27.71, 29.28, 32.26, 40.55,
41.30, 50.68, 111.61, 118.80, 121.11, 123.58, 123.77, 129.21, 129.87, 133.13, 142.20,
143.97, 146.20, 146.86, 151.25, 164.42 and 196.94. Anal. calcd. for C28H26N2O6: C,
69.12; H, 5.39; N, 5.76. Found: C, 69.20; H, 5.43; N, 5.76.
5-Benzylidene-3,3,7-trimethyl-9-phenyl-3,4,5,6,7,8-hexahydro-2H-
xanthen-1(9H)-one (Entry 18, 3r)
White crystals, IR (KBr): 3025, 2956, 1663, 1628, 1377, 1221, 1141, 699 cmꢁ1
;
1H NMR (400 MHz, CDCl3): d ¼ 0.92 (d, 3H, J ¼ 6.4 Hz, CH3), 1.12 (S, 3H, CH3),
1.15 (S, 3H, CH3), 1.67–1.74 (m, 1H, CH), 1.77–1.90 (m, 1H, CH), 2.04–2.18 (m,
1H, CH), 2.20–2.25 (m, 3H, CH2, CH), 2.57 (d, 2H, J ¼ 12.4 Hz, CH2), 2.86–2.90
=
(m, 1H, CH), 4.25 (s, 1H, CH), 7.0 (s, 1H, CH), 7.20–7.42 (m, 10H, ArH);
13C NMR (100 MHz, CDCl3): 21.08, 21.14, 27.49, 29.14, 32.18, 35.25, 39.80, 40.76,
41.40, 50.86, 112.58, 112.67, 117.47, 122.23, 126.56, 128.20, 128.31, 128.56, 129.33,
130.13, 137.45, 142, 144.11, 164.21 and 197.20. Anal. calcd. for C29H30O2: C,
84.84; H, 7.37. Found: C, 8475; H, 7.31.
5-(4-Methylbenzylidene)-9-(4-methylphenyl)-3,3,7-trimethyl-3,4,5,6,
7,8-hexahydro-2H-xanthen-1(9H)-one (Entry 19, 3s)
White crystals, IR (KBr): 2956, 2828, 1662, 1628, 1377, 1221, 1142, 735 cmꢁ1
;
1H NMR (400 MHz, CDCl3): d ¼ 0.94 (d, 3H, J ¼ 6 Hz, CH3), 1.09 (S, 3H, CH3),

NEW XANTHENE DERIVATIVES
1197
1.18 (S, 3H, CH3), 1.78–1.88 (m, 2H, CH2), 2.04–2.19 (m, 2H, CH2), 2.21–2.31 (m,
2H, CH2), 2.33 (s, 3H, CH3), 2.42 (s, 3H, CH3), 2.58 (d, 2H, J ¼ 12.4 Hz, CH2),
=
2.89–2.93 (m, 1H, CH), 4.21 (s, 1H, CH), 6.99 (s, 1H, CH), 7.11 (d, 2H, J ¼ 7.1 Hz,
Hz, ArH), 7.22–7.30 (m, 6H, ArH); 13C NMR (100 MHz, CDCl3): 21.19, 21.31,
27.42, 27.54, 29.20, 29.46, 34.95, 36.43, 39.39, 40.37, 41.38, 50.92, 112.68, 112.77,
117.30, 122.04, 128.14, 128.96, 129.06, 129.56, 134.55, 136.03, 141.25, 141.50,
163.84, 164.17 and 197.29. Anal. calcd. for C31H34O2: C, 84.89; H, 7.81. Found:
C, 84.93; H, 7.83.
5-(4-Methoxybenzylidene)-9-(4-methoxyphenyl)-3,3,7-trimethyl-3,4,
5,6,7,8-hexahydro-2H-xanthen-1(9H)-one (Entry 20, 3t)
White crystals, IR (KBr): 29.55, 28.33, 1661, 1627, 15.09, 1377, 1250, 1174,
1
1036, 835 cmꢁ1; H NMR (400 MHz, CDCl3): d ¼ 0.93 (d, 3H, J ¼ 6.4 Hz, CH3),
1.06 (S, 3H, CH3), 1.15 (S, 3H, CH3), 1.77–1.88 (m, 2H, CH2), 2.0–2.11 (m, 2H,
CH2), 2.18–2.30 (m, 2H, CH2), 2.55 (d, 2H, J ¼ 11.2 Hz, CH2), 2.85–2.89 (m, 1H,
CH), 3.80 (s, 3H, OCH3), 3.86 (s, 3H, OCH3), 4.15 (s, 1H, CH), 6.82–6.86 (m, 2H,
=
ArH), 6.92–6.93 (m, 2H, ArH), 6.95 (s, 1H, CH), 7.22–7.26 (m, 2H, ArH),
7.28–7.31 (m, 2H, ArH); 13C NMR (100 MHz, CDCl3): d ¼ 21.17, 21.33, 27.37,
27.49, 28.78, 29.12, 38.85, 39.83, 41.36, 50.90, 55.19, 55.30, 112.74, 112.82, 116.91,
117.10, 121.60, 128.70, 128.94, 129.17 129.97, 130.56, 141.99, 158.19, 163.74, 164.09
and 197.37. Anal. calcd. for C31H34O4: C, 79.12; H, 7.28. Found: C, 79.06; H, 7.31.
5-(4-Chlorobenzylidene)-9-(4-chlorophenyl)-3,3,7-trimethyl-3,4,5,6,7,
8-hexahydro-2H-xanthen-1(9H)-one (Entry 21, 3u)
White crystals, IR (KBr): 2957, 2828, 1662, 1628, 1488, 1376, 1221, 1090, 1014,
1
837 cmꢁ1; H NMR (400 MHz, CDCl3): d ¼ 0.93 (d, 3H, J ¼ 6.4 Hz, CH3), 1.02 (S,
3H, CH3), 1.14 (S, 3H, CH3), 1.61–1.80 (m, 1H, CH), 1.86–1.88 (m, 1H, CH),
1.98–2.01 (m, 1H, CH), 2.16–2.29 (m, 3H, CH2, CH), 2.55 (d, 2H, J ¼ 11.2 Hz,
=
CH2), 2.79–2.83 (m, 1H, CH), 4.21 (s, 1H, CH), 6.92 (s, 1H, CH), 7.25–7.28 (m,
6H, ArH), 7.34–7.37 (m, 2H, ArH); 13C NMR (100 MHz, CDCl3): d ¼ 21.04, 21.10,
27.44, 29.0, 29.39, 34.89, 36.27, 40.20, 41.35, 50.80, 112.22, 112.30, 117.27, 121.36,
128.40, 128.50, 129.89, 130.55, 132.43, 135.74, 142.03, 142.62, 163.93, 164.26 and
197.16. Anal. calcd. for C29H28Cl2O2: C, 72.65; H, 5.89. Found: C, 72.62; H, 5.91.
5-(2-Chlorobenzylidene)-9-(2-chlorophenyl)-3,3,7-trimethyl-3,4,5,6,7,
8-hexahydro-2H-xanthen-1(9H)-one (Entry 22, 3v)
White crystals, IR (KBr): 2956, 2926, 1664, 1629, 1439, 1376, 1222, 1115, 1046,
1
748 cmꢁ1; H NMR (400 MHz, CDCl3): d ¼ 0.88 (d, 3H, J ¼ 6.4 Hz, CH3), 1.05 (S,
3H, CH3), 1.17 (S, 3H, CH3), 1.64–1.71 (m, 1H, CH), 1.88–1.89 (m, 1H, CH),
2.02–2.05 (m, 1H, CH), 2.18–2.31 (m, 3H, CH2, CH), 2.55–2.66 (m, 3H, CH2,
=
CH), 4.85 (s, 1H, CH), 7.03 (s, 1H, CH), 7.21–7.30 (m, 6H, ArH), 7.36 (d, 1H,
J ¼ 7.2 Hz, ArH), 7.44 (d, 1H, J ¼ 7.2 Hz, ArH); 13C NMR (100 MHz, CDCl3):
d ¼ 20.99, 27.58, 28.50, 28.93, 29.39, 35.22, 35.67, 37.25, 41.69, 50.78, 111.85,
117.58, 119.74, 119.84, 126.23, 127.05, 127.70, 128.09, 129.48, 130.23, 130.75,

1198
Z. KARIMI-JABERI AND B. POOLADIAN
131.35, 131.57, 133.67, 134.12, 135.64, 141.27, 164.56 and 196.97. Anal. calcd. for
C29H28Cl2O2: C, 72.65; H, 5.89. Found: C, 72.59; H, 5.84.
5-(4-Fluorobenzylidene)-9-(4-fluorophenyl)-3,3,7-trimethyl-3,4,5,6,7,
8-hexahydro-2H-xanthen-1(9H)-one (Entry 23, 3w)
White crystals, IR (KBr): 2957, 2829, 1663, 1629, 1505, 1377, 1222, 1157,
1
842 cmꢁ1; H NMR (400 MHz, CDCl3): d ¼ 0.94 (d, 3H, J ¼ 6.8 Hz, CH3), 1.02 (S,
3H, CH3), 1.14 (S, 3H, CH3), 1.68–1.77 (m, 1H, CH), 1.82–1.89 (m, 1H, CH),
1.99–2.19 (m, 1H, CH), 2.21–2.30 (m, 3H, CH2, CH), 2.55 (d, 2H, J ¼ 11.6 Hz,
=
CH2), 2.80–2.83 (m, 1H, CH) 4.22 (s, 1H, CH), 6.94 (s, 1H, CH), 6.95–7.0 (m,
2H, ArH), 7.06–7.10 (m, 2H, ArH), 7.26–7.33 (m, 4H, ArH); 13C NMR (100 MHz,
CDCl3): d ¼ 21.12, 27.43, 28.74, 29.0, 29.38, 32.18, 35.15, 36.27, 39.97, 50.81,
112.52 (d, J ¼ 32 Hz), 115.01 (d, J ¼ 36 Hz), 115.22 (d, J ¼ 36 Hz), 117.14, 117.35,
121.37 (d, J ¼ 20 Hz), 129.65 (d, J ¼ 32 Hz), 129.94 (d, J ¼ 32 Hz), 130.85(d,
J ¼ 32 Hz), 133.33, 139.84, 141.54, 160.35 (d, J ¼ 32 Hz), 167.17 and 197.22. Anal.
calcd. for C29H28F2O2: C, 78.0; H, 6.32. Found: C, 79.01; H, 6.37.
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