Cyclohexenones through regioselective addition of 1,3-dicarbonyl compounds to terpenoid-like bischalcones

Article abstract of DOI:10.1080/00397910902793877

Terpenoid-like bischalcones (3 and 4) were synthesized from the reaction of-and-ionones and benzaldehydes in excellent yields. The Michael addition of 1,3-dicarbonyl compounds to bischalcones (3 and 4) resulted in the formation of cyclohexenones derivativ

Full text of DOI:10.1080/00397910902793877

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Cyclohexenones Through
Regioselective Addition of
1,3-Dicarbonyl Compounds to
Terpenoid-Like Bischalcones
Esra Findik a , Yakup Budak a & Mustafa Ceylan a
a Department of Chemistry , Faculty of Arts and
Sciences, Gaziosmanpasa University , Tokat, Turkey
Published online: 08 Sep 2009.
To cite this article: Esra Findik , Yakup Budak & Mustafa Ceylan (2009)
Cyclohexenones Through Regioselective Addition of 1,3-Dicarbonyl Compounds to
Terpenoid-Like Bischalcones, Synthetic Communications: An International Journal
for Rapid Communication of Synthetic Organic Chemistry, 39:20, 3647-3656, DOI:
10.1080/00397910902793877
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Synthetic Communications1, 39: 3647–3656, 2009
Copyright # Taylor & Francis Group, LLC
ISSN: 0039-7911 print=1532-2432 online
DOI: 10.1080/00397910902793877
Cyclohexenones Through Regioselective
Addition of 1,3-Dicarbonyl Compounds
to Terpenoid-Like Bischalcones
Esra Findik, Yakup Budak, and Mustafa Ceylan
Department of Chemistry, Faculty of Arts and Sciences,
Gaziosmanpasa University, Tokat, Turkey
Abstract: Terpenoid-like bischalcones (3 and 4) were synthesized from the
reaction of a- and b-ionones and benzaldehydes in excellent yields. The Michael
addition of 1,3-dicarbonyl compounds to bischalcones (3 and 4) resulted in the
formation of cyclohexenones derivatives (10a–d and 14a, b) via regioselective
addition of 1,3-dicarbonyls and then cyclization.
Keywords: Cyclization, cyclohexenones, regioselective addition, terpenoid-like
bischalcone
1,5-Diaryl-1,4-pentadien-3-ones (bischalcones) are important intermediates
and raw materials widely used as precursors to drugs,[1] nonlinear optical
materials, organometallic materials,[2,3] and polymers.[4] The Michael
reaction of bischalcones with active methylene compounds such as
1,3-dicarbonyl compounds has been the subject of many investiga-
tions.[5–9] It is known that a weak base or acid such as piperidine[10] or
phosphorustrichloride[11] often affords open-chain adducts, whereas
cyclic products have been obtained in the presence of sodium methoxide
or sodium hydroxide.[12] Particularly, the products of these cyclic
reactions are of interest in terms of their stereochemistry and as starting
materials for the synthesis of compounds with possible biological activity.
Received December 23, 2008.
Address correspondence to Esra Findik, Department of Chemistry, Faculty of
Arts and Sciences, Gaziosmanpasa University, 60250 Tokat, Turkey. E-mail:
mceylan@gop.edu.tr
3647

3648
E. Findik, Y. Budak, and M. Ceylan
Reddy et al.[13] have reported that the synthesis of 1,1-disubstituted-2,
6-diarylcyclohexane-4-ones was carried out in moderate to good yields
via double Michael addition of bis-chalcone with active methylene
compounds in the presence of sodium methoxide. Addition, the Michael
reaction of chalcones with 1,3-dicarbonyl compounds may be exploited
with the view of obtaining highly functionalized cyclohexene derivatives
but is more commonly used for the preparation of 3,5-diaryl-6-
substituted cyclohexenones. The mentioned cyclohexenones are efficient
synthons in benzoselenadiazoles and benzothiadiazoles,[14] benzo-
pyrazoles and benzisoxazoles,[15,16] and carbazole derivatives.[17]
In this study, we report synthesis of cyclohexenone derivatives by
regioselective Michael addition of 1,3-dicarbonyl compounds to bischal-
cones (3 and 4), the latter which were obtained by intramolecular
Knoevenagel condensation of the methyl group in 1,3-dicarbonyl
compounds. The formation of these products was confirmed by infrared
1
(IR) and H NMR spectral studies.
The terpenoid-like bischalcones 3 and 4 were synthesized from the
reaction of a- and b-ionones with the benzaldehyde in yields of 90%
and 89%, respectively (Scheme 1). The reactions were performed in the
presence of aqueous NaOH in ethanol (EtOH) at room temperature
for 3 h. The compounds 3 and 4 are best known in the literature.[18–22]
The reaction of chalcones and bischalcones with 1,3-dicarbonyl
compounds is known to lead to three structurally diverse types of
compounds, depending on the experimental conditions employed: pyry-
lium salts,[23] Michael addition products,[24] and cyclohexenone deriva-
tives. The catalyst plays a key role in directing the reaction to different
end products. The basic catalyst would turn the intermediate Michael
addition product into cyclohexenones through the intramolecular cyclo-
condensation of the methyl group originating from 1,3-dicarbonyl com-
pounds and the ketone function of the initial a,b-unsaturated
system.[25] In this research, acetylacetone (5), methyl acetoacetate (6),
ethyl acetoacetate (7), and N,N-diethyl-3-oxobutanamide (8) were chosen
as 1,3-dicarbonyl compounds. The reaction of 3 with 1,3-dicarbonyl
Scheme 1. Synthesis of bischalcones.

Cyclohexenones Through Regioselective Addition
3649
Scheme 2. Addition of 1,3-dicarbonyls to bischalcone (3).
compounds 5–8 in basic medium resulted in the formation 3,5,6-trisubsti-
tuted cyclohexenones derivatives (10a–d) by means of an intermediate
Michael adduct, as outlined in Scheme 2.
The reaction of 4 with acetylacetone (5), methyl acetoacetate (6), and
ethyl acetoacetate (7) in the same conditions gave the 3,5-disubstituted
cyclohexenone 14a and 3,5,6-trisubstituted cyclohexenone 14b, different
from that of 3.
Control of selectivity, for example, chemo- and regioselectivity, is
among the most important objectives in organic chemistry. In this reac-
tion, 1,3-dicarbonyl compounds may be added to two sides (phenyl side
or cyclohexenyl side) of bischalcones 3 and 4. It was observed that the
1,3-dicarbonyl compounds were added as regioselective from the phenyl
side of bischalcones 3 and 4 (Scheme 3).
The formation of compound 14a may be explained by two different
mechanisms, depicted in Scheme 4. Path a: Compound 13 converted to
compound 14a by elimination of CO2, and EtOH, and=or MeOH effect
Scheme 3. Addition of 1,3-dicarbonyls to bischalcone (4).

3650
E. Findik, Y. Budak, and M. Ceylan
Scheme 4. Formation mechanism of cyclohexanone derivatives (14a–b).
of base and temperature.[26] Path b: Lactone compound 12 may be
occurring by the intramolecular esterification of intermediate 11 and
elimination of CO2 from 12 (acting base) to give 14a.
The structure of cyclohexenone derivatives 10a–d and 14a, b were
1
elucidated by spectroscopic studies (IR, H and 13C NMR, elemental
analysis) and comparison with literature data.
In conclusion, the reaction of bischalcones with 1,3-dicarbonyl
compounds in the presence of sodium ethoxide has been shown to
afford cyclohexenone derivatives via Michael addition followed by
intramolecular cyclocondensation.
EXPERIMENTAL
Instruments
IR spectrums (KBr or liquid) were recorded on a Jasco Fourier
1
Transform (FT) IR-430 spectrometer. H and 13C NMR spectra were
recorded on a Brucker Avance III instrument. Internal standards
were tertramethylsilane (TMS, d 0.00) for 1H NMR and CDCl3 (d
77.0) for 13C NMR spectroscopy. J values are given in hertz. The
1
multiplicities of the signals in the H NMR spectra are abbreviated by
s (singlet), d (doublet), t (triplet), q (quartet), m (multiplet), br (broad),
and combinations thereof. Elemental analyses were obtained from a
LECO CHNS 932 elemental analyzer.

Cyclohexenones Through Regioselective Addition
3651
Reagents a-ionone, b-ionone, benzaldehyde, and 1,3-dicarbonyl
compounds were commercial products of highest reagent grade.
Synthesis of Bischalcones 3 and 4
A solution of NaOH (0.26 g, 6.5 mmol) in water was added to a stirred
solution of ionone (0.5 g, 2.6 mmol) and benzaldehyde (2,6 mmol) in
ethanol (10 ml) and stirred at room temperature for 3 h. The reaction
was complete; the mixture was diluted with CHCl3, treated with HCl
solution (10%), and washed with water. The organic layer was dried over
anhydrous Na2SO4. The solvent was evaporated. The crude product was
chromatographed on a silica-gel column, eluting with CHCl3=petroleum
ether (2:8).
1-Phenyl-5-(2,6,6-trimethylcyclohex-2-enyl)penta-1,4-dien-3-one (3)
Viscous oil; 1H NMR (400 MHz, CDCl3) d ¼ 7.66 (d, J ¼ 16 Hz, 1H, H1,
A part of AB system), 7.55–7.54 (m, 2H, ArH), 7.35–7.34 (m, 3H, ArH),
6.99 (d, J ¼ 16 Hz, 1H, H2, B part of AB systym), 6.83 (dd, J ¼ 15.6,
9.6 Hz, 1H, H5, A part of AB system), 6.39 (d, J ¼ 15.6 Hz, 1H B part
of AB system, H4), 5.48 (m, as if brs, 1H), 2.32 (d, J ¼ 9.6 Hz, 1H),
1.58 (s, 3H), 1.54–2.45 (m, 2H), 1.24–1.18 (m, 2H), 0.93 (s, 3H), 0.87
(s, 3H). 13C NMR (100 MHz, CDCl3): d ¼ 188.76, 148.74, 143.0,
134.81, 131.96, 130.54, 130.34, 128.88 (2C), 128.30 (2C), 124.77, 122.63,
54.52, 32.62, 31.18, 27.89, 26.85, 23.06, 22.91. IR (liquid): 2955, 2915,
1655, 1623, 1598, 1338, 989, 794, 757 cmꢀ1. Anal. calcd. for C20H24O:
C, 85.67; H, 8.63. Found: C, 85.42; H, 8.38.
1-Phenyl-5-(2,6,6-trimethylcyclohex-1-enyl)penta-1,4-dien-3-one (4)
Viscous oil; 1H NMR (400 MHz, CDCl3): d ¼ 7.64 (d, J ¼ 16 Hz, 1H, H1,
A part of AB system), 7.55–7.52 (m, 3H, 2ArH and H5), 734–7.33 (m,
3H, ArH), 6.99 (d, J ¼ 16 Hz, 1H, H2, B part of AB system), 6.47 (d,
J ¼ 16 Hz, 1H, B part of AB system, H4), 2.06–2.04 (m, 2H), 1.80 (s,
3H), 1.61–1.59 (m, 2H), 1.48–1.46 (m, 2H), 1.09 (s, 6H). 13C NMR
(100 MHz, CDCl3): d ¼ 188.21, 142.92, 142.63, 136.61, 136.48, 134.89,
130.28, 129.56, 128.88 (2C), 128.27 (2C), 125.66, 39.69, 34.14, 33.69,
28.87 (2C), 21.89, 19.08. IR (liquid): 2958, 2930, 2865, 1671, 1653,
1612, 1449, 1333, 1088, 982, 786, 758 cmꢀ1. Anal. calcd. for C20H24O:
C, 85.67; H, 8.63. Found: C, 85.74; H, 8.47.

3652
E. Findik, Y. Budak, and M. Ceylan
General Procedure for Synthesis of Cyclohexenone Derivatives
(10a–d and 14a, b)
Bischalcone (3–4) (1.78 mmol) and 1,3-dicarbonyl (5–8) (1.78 mmol) were
refluxed 3 h in 10–15 mL ethanol in the presence of sodium ethoxide
(0.1 mmol). Water was added to the mixture and extracted with EtOAc
(3 ꢁ 20 mL), dried over anhydrous Na2SO4, and evaporated. Crude
products were purified by column chromatography on silica gel or
preparative thin-layer chromatography (TLC; 20 ꢁ 20 cm plates, 2 mm
thick) using n-hexane=EtOAc (9:1) as eluent.
6-Acetyl-5-phenyl-3-(2-(2,6,6-trimethylcyclohex-2-enyl)vinyl)
cyclohex-2-enone (10a)
Yield: 78%; viscous oil. IR n (KBr): 3085, 3061, 3025, 2957, 2918, 2867, 1660,
1624, 1453, 1382, 1363, 1292, 1252, 1216, 970, 755, 700, 667 cmꢀ1; 1H NMR
(400 MHz, CDCl3): d ¼ 7.39–7.25 (m, 5H), 6.26 (d, J¼ 15.6 Hz, 1H, H7),
6.09–6.02 (m, 2H, H8 and H2), 5.47 (m, as if brs, 1H, H10), 3.35–3.32 (m,
2H, H4), 2.89–2.81 (m, 1H, H5), 2.72–2.68 (m, 1H, H6), 2.26 (d, J¼ 9.2 Hz,
Hz, 1H, H2), 2.02 (s, 3H, -CH3) 1.60 (s, 3H, –CH3), 1.42–1.37 (m, 2H, H11),
1.23–1.16 (m, 2H, H12), 0.94 (s, 3H, –CH3), 0.83 (s, 3H, -CH3); 13C NMR
(100 MHz, CDCl3): d ¼ 199.66, 156.32, 143.48, 140.39, 132.03, 128.97,
128.89, 128.81, 127.31, 126.95, 126.82, 126.53, 122.68, 55.11, 44.53, 40.74,
38.99, 33.52, 32.61, 31.33, 27.90, 26.88, 23.03. Anal. calcd. for C25H30O2:
C, 82.83; H, 8.34; O, 8.83. Found: C, 82.75; H, 8.29; O, 8.74.
Methyl 2-Oxo-6-phenyl-4-(2-(2,6,6-trimethylcyclohex-
2-enyl)vinyl)cyclohex-3-ene-carboxylate (10b)
Yield: 81%; yellowish liquid. IR n (KBr): 3086, 3062, 2954, 2916, 1668,
1
1624, 1455, 1374, 1240, 1115, 1096, 971, 760, 732, 700 cmꢀ1; H NMR
(400 MHz, CDCl3): d ¼ 7.37–7.26 (m, 5H), 6.24 (d, J ¼ 15.6 Hz, 1H,
H7), 6.07–6.0 (m, 2H, H8 and H2), 5.46 (m, as if brs, 1H, H10),
3.75–3.68 (m, 2H, H4), 3.57 (s, 3H, -OCH3), 2.89–2.84 (m, 1H, H5),
2.65–2.56 (m, 1H, H6), 2.26 (d, J ¼ 9.6 Hz, 1H, H9), 1.57 (s, 3H,
–CH3), 1.44–1.36 (m, 2H, H11), 1.22–1.17 (m, 2H, H12), 0.92 (s, 3H,
–CH3), 0.82 (s, 3H, -CH3); 13C NMR (100 MHz, CDCl3): d ¼ 194.24,
169.87, 156.22, 141.36, 141.24, 132.66, 131.45, 128.87, 127.49, 127.23,
125.20, 122.14, 59.96, 59.89, 55.13, 52.01, 43.57, 33.28, 32.64, 31.28,
27.96, 26.79, 23.00. Anal. calcd. for C25H30O3: C, 79.33; H, 7.99; O,
12.68. Found: C, 79.35; H, 7.91; O, 12.63.

Cyclohexenones Through Regioselective Addition
3653
Ethyl-2-oxo-6-phenyl-4-(2-(2,6,6-trimethylcyclohex-2-
enyl)vinyl)cyclohex-2-enone (10c)
Yield: 70%; yellowish liquid. IR n (KBr): 3086, 3062, 2958, 2916, 1666,
1625, 1455, 1381, 1336, 1291, 1258, 970, 757, 700 cmꢀ1 1H NMR
;
(400 MHz, CDCl3): d ¼ 7.33–7.29 (m, 5H), 6.24 (d, J ¼ 15.6 Hz, 1H,
H7), 6.07–6.03 (m, 2H, H8 and H2), 5.45 (m, as if brs, 1H, H10), 4.00
(q, J ¼ 7.1 Hz, 2H, CH2CH3), 3.73–3.64 (m, 2H, H4), 2.89–2.83 (m, 1H,
H5), 2.67–2.56 (m, 1H, H6), 2.26 (d, J ¼ 9.85 Hz, 1H, H9), 1.59 (s, 3H,
–CH3); 1.44–1.37 (m, 2H, H11), 1.21–1.17 (m, 2H, H12), 1.01
(t, J ¼ 7.1 Hz, 3H, –CH2CH3), 0.92 (s, 3H, –CH3), 0.81 (s, 3H, –CH3);
13C NMR (100 MHz, CDCl3): d ¼ 194.20, 169.24, 157.00, 141.24,
141.10, 132.63, 131.56, 128.84, 128.76, 127.43, 127.37, 125.35, 122.12,
55.13, 55.08, 43.74, 33.32, 32.63, 32.60, 32.32, 27.95, 26.84, 23.01,
22.93. Anal. calcd. for C26H32O2: C, 82.94; H, 8.57; O, 8.50. Found: C,
82.98; H, 8.61; O, 8.41.
N,N-Diethyl-2-oxo-6-phenyl-4-(2-(2,6,6-trimethylcyclohex-2-
enyl)vinyl)cyclohex-3-enecarboxamide (10d)
Yield: 75%; yellowish liquid. IR n (KBr): 3086, 3062, 2965, 2930, 2896,
1661, 1626, 1454, 1381, 1362, 1280, 1211, 1131, 1099, 1078, 971, 756,
701, 666 cmꢀ1
;
1H NMR (400 MHz, CDCl3): d ¼ 7.34–7.20 (m, 5H),
6.22 (d, J ¼ 15.6 Hz, 1H, H7), 6.06–6.00 (m, 2H, H8 and H2), 5.43 (m,
as if brs, 1H, H10), 3.93–3.78 (m, 2H, H4), 3.38–3.32 (m, 4H,
–NCH2CH3), 2.91–2.85 (m, 1H, H5), 2.73–2.65 (m, 1H, H6), 2.25 (d,
J ¼ 9.4 Hz, 1H, H9), 1.56 (s, 3H, –CH3), 1.42–1.37 (m, 2H, H11),
1.19–1.16 (m, 2H, H12), 0.89 (s, 3H, –CH3), 0.84 (t, J ¼ 6.8 Hz, 6H,
–NCH2CH3), 0.79 (s, 3H, –CH3); 13C NMR (100 MHz, CDCl3):
d ¼ 195.63, 168.19, 156.02, 142.06, 140.79, 132.73, 131.75, 128.49,
127.72, 127.08, 125.93, 122.03, 56.36, 55.08, 43.49, 42.77, 40.59, 32.57,
32.08, 31.34, 27.90, 26.82, 22.91, 22.88, 14.48, 12.71. Anal. calcd. for
C28H37NO2: C, 80.15; H, 8.89; O, 7.63; N, 3.34. Found: C, 80.11; H,
8.78; O, 7.68; N, 3.29.
5-Phenyl-3-(2-(2,6,6-trimethylcyclohex-1-enyl)vinyl)cyclohex-2-
enone (14a)
Yield: 68%; yellowish liquid. IR n (KBr): 3086, 3061, 2956, 2928, 2864,
1
1660, 1607, 1454, 1379, 1360, 1287, 1257, 970, 757, 699 cmꢀ1; H NMR
(400 MHz, CDCl3): d ¼ 7.38–7.32 (m, 5H), 6.66 (d, J ¼ 16.2 Hz, 1H, H9

3654
E. Findik, Y. Budak, and M. Ceylan
or H8), 6.26 (d, J ¼ 16.2 Hz, 1H, H9 or H8), 6.06 (s, 1H, H2), 3.76–3.71
(m, 2H, H4), 2.98–1.93 (m, 1H, H5), 2.71–2.64 (m, 2H, H6), 1.74 (s, 3H,
–CH3), 1.63–1.59 (m, 4H, H10 and H11), 1.48–1.45 (m, 2H, H12), 1.02 (s,
6H, 2 ꢁ –CH3); 13C NMR (100 MHz, CDCl3): d ¼ 194.19, 169.36, 156.50,
141.30, 136.97, 136.24, 133.31, 132.67, 128.79, 127.42, 125.39, 44.08,
39.50, 34.15, 33.21, 32.97, 28.95, 28.91, 21.81, 19.01. Anal. calcd. for
C23H28O: C, 86.20; H, 8.81; O, 4.99. Found: C, 86.24; H, 8.87; O, 4.89.
6-Acetyl-5-phenyl-3-(2-(2,6,6-trimethylcyclohex-1-enyl)vinyl)
cyclohex-2-enone (14b)
Yield: 73%; yellowish liquid. IR n (KBr): 3088, 3064, 2966, 2932, 1653,
1
1622, 1455, 1379, 1295, 1258, 975, 760, 699 cmꢀ1; H NMR (400 MHz,
CDCl3): d ¼ 7.42–7.36 (m, 2H), 7.34–7.30 (m, 3H), 6.66 (d, J ¼ 16.2 Hz,
1H, H9 or H8), 6.26 (d, J ¼ 16.2 Hz, 1H, H9 or H8), 6.03 (s, 1H, H2),
3.47–3.33 (m, 2H, H4), 2.94–2.89 (m, 1H, H5), 2.60–2.56 (m, 1H, H6),
2.05 (s, 3H, –CH3), 1.74 (s, 3H, –CH3), 1.64–1.56 (m, 4H, H10 and
H11), 1.49–1.46 (m, 2H, H12), 1.03 (s, 3H, –CH3), 1.02 (s, 3H, –CH3);
13C NMR (100 MHz, CDCl3): d ¼ 199.54, 156.68, 143.58, 137.06,
135.41, 133.27, 132.74, 128.83, 128.72, 127.05, 126.87, 126.48, 44.54,
40.74, 39.49, 34.22, 33.21, 33.14, 28.94, 28.91, 21.78, 19.01. Anal. calcd.
for C25H30O2: C, 82.83; H, 8.34; O, 8.83. Found: C, 82.60; H, 8.40; O,
8.78.
ACKNOWLEDGMENTS
The authors are indebted to the Department of Chemistry (Gaziosmapasa
University) and the Scientific and Technical Research Council of Turkey
˙
(Grants TUBITAK-TBAG 106T103 and TUBITAK-BIDEP) for financial
support.
REFERENCES
1. Anto, R. J.; Sukumaran, K.; Kuttan, G.; Rao, M. N. A.; Subbaraju, V.;
Kuttan, R. Anticancer and antioxidant activity of synthetic chalcones and
related compounds. Cancer Lett. 1995, 97 (1), 33–37.
2. Turowska, I. T. Monitoring initial structural changes in a crystal during
photo-induced disappearance of its diffracting properties. Chem. Phys.
2003, 288, 241–247.
3. Burrows, A. D.; Choi, N.; McPartlin, M.; Mingos, D. M. P.; Tarlton, S. V.;
Vilar, R. Syntheses and structural characterisation of the compounds

Cyclohexenones Through Regioselective Addition
3655
[Pd2(dba)3] (where L ¼ PBz3 and PPh2Np) and of the novel dimer [Pd2
(m-dba)(m-SO2)(PBz3)2]. J. Organomet. Chem. 1999, 573, 313.
4. Insuasty, B.; Rodriguez, R.; Quiroga, J.; Abonia, R.; Martinez, R.; Toscano,
A.; Angeles, E. Synthesis of 1-benzyl-6-(4-chlorophenyl)-2-(4-R-phenyl)-4-(4-
R-styryl)-2,3-dihydropyrazolo[3,4-b][1,4]-diazepines. Molecules 2001, 6 (8),
710–715.
5. Helmkamp, R. W.; Tanghe, L. J.; John, J.; Plati, J. T. Some Michael con-
densations involving benzyl cyanide. J. Am. Chem. Soc. 1940, 62 (11), 3215–
3219.
6. Kohler, E. P.; Helmkamp, R. W. The addition reactions of certain pentadie-
nones. J. Am. Chem. Soc. 1924, 46, 1018–1024.
7. Kohler, E. P.; Dewey, C. S. The addition reactions of certain pentadienones,
II: Addition of malonic esters. J. Am. Chem. Soc. 1924, 46, 1267.
8. Hoeve, W. T.; Wynberg, H. Chiral spiranes. Optical activity and nuclear
magnetic resonance spectroscopy as a proof for stable twist conformation.
J. Org. Chem. 1979, 44 (9), 1508–1514.
9. Rowland, A. T.; Filla, S. A.; Coutlangus, M. L. On the stereochemistry of
diaryl-substituted cyclohexanone formed by Michael reactions: Trans to cis
¨
isomerization of their ketals under basic conditions. J. Org. Chem. 1998,
63 (13), 4359–4365.
¨
10. Borsche, W. Uber die Verteilung der Affinitat in ungesattigten organischen
Verbindungen. Liebigs. Ann. chem. 1910, 375, 145–180.
11. Canant, J. B.; Bump, A. H.; Holt, H. S. Addition reactions of phosphorus
halides, III: The reaction with dibenzal-acetone and cinnamylidene-
acetophenone. J. Am. Chem. Soc. 1921, 43 (7), 1677–1684.
12. Loganathan, D.; Verghese, T.; Trivedi, G. K. Phase-transfer catalysed
single-pot preparation of 7,11-bisarylspiro (5,5)-undecane-1,9-dione. Org.
Prep. Proced. Intl. 1984, 16, 115–119.
13. Reddy, D. B.; Padmavathi, V.; Reddy, M. M. Double Michael addition reac-
tions of bischalcones. Indian J. Chem. 1992, 31B, 407.
14. Tabba, H. D.; Yousef, N. M.; Al-Arab, M. M. Michael–Michael aldol
reaction of chalcones with cyanoacetylurea and cyanoacetylpiperidine. Coll.
Czech. Chem. Commun. 1995, 60 (4), 594–604.
15. Reddy, D. B.; Reddy, A. S.; Padmavathi, V. Synthesis of annelated
1,2,3-selena- or thia-diazoles. J. Chem. Res., Synop. 1998, 784–785.
16. Padmavathi, V.; Mohan Reddy, B. J.; Balaiah, A.; Venugopal Reddy, K.;
Bhaskar Reddy, D. Synthesis of some fused pyrazoles and isoxazoles.
Molecules 2000, 5, 1281–1286.
17. Padmavathi, V.; Sharmila, K.; Balaiah, A.; Reddy, A. S.; Reddy, D. B.
Cyclohexenone carboxylate: A versatile source for fused isoxazoles and
pyrazoles. Synth. Commun. 2001, 31, 2119–2126.
18. Padmavathi, V.; Sharmila, K.; Padmaja, A.; Reddy, D. B. An efficient synth-
esis of 6,8-diaryl-carbazoles via Fischer indole cyclizations. Heterocycl.
Commun. 1999, 5, 451–456.
19. Gandhi, R. P.; Kumar, S.; Aryan, R. C.; Ishar, M. P. S. Regioselective
photoelectro-cyclization of (E=E)-arylidene-b-ionones: Synthesis of some

3656
E. Findik, Y. Budak, and M. Ceylan
1,7,7-trimethyl-3-(e-20-arylethenyl)-2-oxabicyclo
Synth. Commun. 1989, 19 (9–10), 1759–1762.
[4.4.0]
deca-3,5-dienes.
20. Gandhi, R. P.; Aryan, R. C. Photochemical reorganisation of 1,7,7-
trimethyl-3-(E-2-arylethenyl)-2-oxabicyclo[4.4.0]deca-3,5-dienes. J. Chem.
Soc., Chem. Commun. 1988, 15, 1024–1025.
21. Ter-Sarkisyan, G. S.; Mikhailov, B. M. Reactions of 1-(2,6,6-trimethyl-2-
cyclohexenyl)-3-(ethylthio)-1,3-butadiene with thioacetals. Zhurnal Organi-
cheskoi Khimii 1965, 1 (7), 1239–1241.
22. Ishar, M. P. S.; Rai, T.; Agrawal, S. K.; Saxena, A. K.; Singh, L.; Ss¸ngh, R.;
Bhella, S. S. Synthesis and cytotoxic activity of some novel polycyclic
c-butyrolactones. Bioorg. Med. Chem. Lett. 2008, 18 (17), 4809–4812.
23. Ishar, M. P. S.; Singh, R.; Kumar, K.; Singh, G.; Velmurugan, D.; Subbiah,
H. A.; Sundra, R. S. S.; Fun, H. K. Photochemistry of arylidene-b-ionones: A
highly efficient route to novel tricyclic ketones through intramolecular, exo-
selective photochemical (4 þ 2) cycloadditions, occurring only in an aqueous
organic solvent. J. Org. Chem. 2002, 67 (7), 2234–2240.
24. Davey, W.; Gwilt, J. R. Chalcones and related compounds, part II: Addition
of thiols and esters to the chalcone system. J. Chem. Soc. 1957, 1015–1017.
25. Van Allan, J. A.; Reynolds, G. A. Preparation of certain pyrylium salts by
using chalcone and boron trifluoride etherate. J. Org. Chem. 1968, 33,
1102–1105.
26. Roman, G. Cyclohexenones through addition of ethyl acetoacetate to chal-
cones derived from 2-acetylthiophene. Acta Chim. Slov. 2004, 51, 537–544.
27. Padmavathi, V.; Reddy, B. J. M.; Balaiah, A.; Reddy, V. K.; Reddy, D. B.
Synthesis of some fused pyrazoles and isoxazoles. Molecules 2000, 5,
1281–1286.