Reaction of substituted chalcones with methyl 1- bromocycloalkanecarboxylates and zinc

Article abstract of DOI:10.1134/S1070363208070244

Methyl 1-bromocyclopentane-and 1-bromocyclobutanecarboxylates react with zinc and substituted chalcones to form spiro-3,4-dihydropyran-2-one derivatives: 8, 10-diaryl-7-oxaspiro[4.5]dec-8-en-6-ones and 7,9-diaryl-6-oxaspiro[3.5]non- 7-en-5-ones, respectiv

Full text of DOI:10.1134/S1070363208070244

ISSN 1070-3632, Russian Journal of General Chemistry, 2008, Vol. 78, No. 7, pp. 1422–1424. © Pleiades Publishing, Ltd., 2008.
Original Russian Text © N.F. Kirillov, A.G. Gavrilov, 2008, published in Zhurnal Obshchei Khimii, 2008, Vol. 78, No. 7, pp. 1189–1191.
Reaction of Substituted Chalcones
with Methyl 1-Bromocycloalkanecarboxylates and Zinc
N. F. Kirillov and A. G. Gavrilov
Perm State University, ul. Bukireva 15, Perm, 614990 Russia
Received December 27, 2007
Abstract—Methyl 1-bromocyclopentane- and 1-bromocyclobutanecarboxylates react with zinc and substituted
chalcones to form spiro-3,4-dihydropyran-2-one derivatives: 8, 10-diaryl-7-oxaspiro[4.5]dec-8-en-6-ones and
7,9-diaryl-6-oxaspiro[3.5]non-7-en-5-ones, respectively.
DOI: 10.1134/S1070363208070244
Ar1
ArCOCH=CHAr1
When reacted with α,β-unsaturated ketones,
Reformatsky reagents add across both 1,2 and 1,4
positions of the conjugated system, and the 1,4-adducts
undergo cyclization affording unsaturated lactones,
specifically dihydropyran-2-one derivatives [1].
I
Ar
OZnBr
MeO
O
IIIа−IIIe
Ar1
We carried out reactions of methyl 1-bromo-
cyclopentane- and 1-bromocyclobutanecarboxy-lates
with zinc and substituted chalcones to obtain similar
compounds with a spiro-carbon atom. Refor-matsky
reagents I and II are formed by the reaction of these
bromoesters with zinc.
−MeOZnBr
Ar
O
O
IVа−IVe
III, IV, Ar = Ph, Ar1 = Ph (а), 4-ClC6H4 (b), 4-BrC6H4 (c);
Ar = 4-BrC6H4, Ar1 = Ph (d); Ar = 4-MeOC6H4, Ar1 = 4-
ClC6H4 (e).
ZnBr
Br
Zn
COOMe
COOMe
I
Vf and then spiro-3,4-dihydropyran-2-ones, namely
7,9-diaryl-6-oxaspiro[3.5]non-7-en-5-ones VIa–VIf.
Ar1
ArCOCH=CHAr1
Br
ZnBr
COOMe
II
II
Ar
Zn
OZnBr
MeO
COOMe
O
Vа−Vf
Ar1
Reformatsky reagent I adds to chalcones across the
1,4 position to give intermediates IIIa–IIIe. Under the
reaction conditions, these intermediates exert cycliza-
tion as a result of the attack of oxygen on the ester
carbonyl carbon to form substituted spiro-3,4-
dihydropyran-2-ones, namely 8,10-diaryl-7-oxaspiro
[4.5]dec-8-en-6-ones IVa–IVe.
−MeOZnBr
Ar
O
O
VIа−VIf
V, VI, Ar = Ph, Ar1 = Ph (a), 4-ClC6H4 (b), 4-BrC6H4 (c);
Ar = 4-BrC6H4, Ar1 = Ph (d); Ar = Ph, Ar1 = 4-MeOC6H4
(e); Ar = Ar1 = 4-ClC6H4 (f).
Reformatsky reagent II reacts with substituted
chalcones in the same way to form intermediates Va–
1422

REACTION OF SUBSTITUTED CHALCONES
1423
1
The yields of the final products were 43–72%. The
composition and structure of compounds IVa–IVe and
VIa–VIf were confirmed by elemental analysis and IR
IR spectrum, ν, cm–1: 1655 (C=C), 1740 (C=O). H
NMR spectrum, δ, ppm: 6.87–7.72 m (9H, Ph, 4-
BrC6H4), 5.91 d (1H, =CH, J 6.5 Hz), 3.37 d (1H,
ArCH, J 6.5 Hz), 0.96–2.21 m [8H, (CH2)4]. Found,
%: C 65.66; H 5.12; Br 20.59. C21H19BrO2. Calculated,
%: C 65.81; H 5.00; Br 20.85.
1
and H NMR spectroscopy. The IR spectra show
characteristic absorption bands of the carbonyl group
at 1740–1770 cm–1 and the C=C bond at 1635–
1
1675cm–1. The H NMR spectra contain signals of the
8-(4-Bromophenyl)-10-phenyl-7-oxaspiro[4.5]dec-
aryl protons at 6.70–7.72 ppm, doublets of the double-
bond protons at 5.80–5.92 ppm, doublets of the
methine protons at 3.37–3.45 ppm (IV) and 3.65–
3.70 ppm (VI), and signals of the cyclohexene ring
protons at 0.91–2.25 ppm.
8-en-6-one (IVd). Yield 1.52 g (45%), mp 113–114°C.
1
IR spectrum, ν, cm–1: 1635 (C=C), 1770 (C=O). H
NMR spectrum, δ, ppm: 6.93–7.58 m (9H, Ph, 4-
BrC6H4), 5.91 d (1H, =CH, J 6.5 Hz), 3.39 d (1H,
ArCH, J 6.5 Hz), 1.20–2.22 m [8H, (CH2)4]. Found,
%: C 66.01; H 5.08; Br 20.72. C21H19 BrO2.
Calculated, %: C 65.81; H 5.00; Br 20.85.
EXPERIMENTAL
10-(4-Chlorophenyl)-8-(4-methoxyphenyl)-7-oxa-
spiro[4.5]dec-8-en-6-one (IVe). Yield 1.57 g (43% ),
mp 118–119°C. IR spectrum, ν, cm–1: 1640 (C=C),
The IR spectra were recorded on a Specord-75IR
spectrophotometer (vaseline oil). The 1Н NMR spectra
were measured on a TESLA BS-576A spectrometer
(100 МHz) in CDCl3 against internal HMDS.
1
1760 (C=O). H NMR spectrum, δ, ppm: 7.50 d, 7.24
d, 6.96 d, 6.74 d (8H, 4-MeOC6H4, 4-ClC6H4, J
8.5 Hz), 5.80 d (1H, =CH, J 6.5 Hz), 3.71 s (3H,
MeO), 3.45 d (1H, ArCH, J 6.5 Hz), 1.00-2.20 m [8H,
(CH2)4]. Found, %: C 71.45; H 5.61; Cl 9.49. C22H21
ClO3. Calculated, %: C 71.64; H 5.74; Cl 9.61.
8,10-Diaryl-7-oxaspiro[4,5]dec-8-en-6-ones IVa–
IVe. A mixture of 11 mmol of methyl 1-bromo-
cyclopentanecarboxylate and 10 mmol of the cor-
responding chalcone in 20 ml of absolute benzene was
added to a mixture of 1.5 g of finely zinc turnings, a
catalytic quantity of mercuric chloride, 1 ml of HMPA,
and 11 ml of anhydrous ethyl acetate. The reaction
mixture was refluxed for 2 h, cooled, filtered, and
hydrolyzed with 5% acetic acid. The organic layer was
separated, and the aqueous layer was extracted with
two portions of ethyl acetate. The combined extract
was dried with anhydrous sodium sulfate, the solvent
was evaporated, and compounds IVa–IVe were
recrystallized from ethyl acetate.
7,9-Diaryl-6-oxaspiro[3.5]non-7-en-5-ones VIa-
VIf were obtained analogously to compounds IVa-IVe
starting from methyl 1-bromocyclobutanecarboxylate.
7,9-Diphenyl-6-oxaspiro[3.5]non-7-en-5-one (VIa).
Yield 1.97 g (68%), mp 110–111°C. IR spectrum, ν,
cm–1: 1665 (C=C), 1750 (C=O). 1H NMR spectrum, δ,
ppm: 6.98–7.70 m (10H, 2Ph), 5.85 d (1H, =CH, J
6.5 Hz), 3.69 d (1H, ArCH, J 6.5 Hz), 1.78–2.56 m
[6H, (CH2)3]. Found, %: C 83.00; H 6.38. C20H18O2.
Calculated, %: C 82.73; H 6.25.
8,10-Diphenyl-7-oxaspiro[4.5]dec-8-en-6-one (IVa).
Yield 1.55 g (51%), mp 115–116°C. IR spectrum, ν,
cm–1: 1645 (C=C), 1755 (C=O). 1H NMR spectrum, δ,
ppm: 6.97–7.68 m (10H, 2Ph), 5.92 d (1H, =CH, J
6.5 Hz), 3.38 d (1H, ArCH, J 6.5 Hz), 1.10–2.22 m
[8H, (CH2)4]. Found, %: C 83.08; H 6.56. C21H20O2.
Calculated, %: C 82.86; H 6.62.
9-(4-Chlorophenyl)-7-phenyl-6-oxaspiro[3.5]non-
7-en-5-one (VIb). Yield 2.18 g (67%), mp 104–105°C.
1
IR spectrum, ν, cm–1: 1650 (C=C), 1760 (C=O). H
NMR spectrum, δ, ppm: 6.91–7.67 m (9H, Ph, 4-
ClC6H4), 5.83 d (1H, =CH, J 6.5 Hz), 3.67 d (1H,
ArCH, J 6.5 Hz), 1.80-2.57 m [6H, (CH2)3]. Found, %:
C 74.12; H 5.17; Cl 11.09. C20H17 ClO2. Calculated, %:
C 73.96; H 5.28; Cl 10.91.
10-(4-Chlorophenyl)-8-phenyl-7-oxaspiro[4.5]dec-
8-en-6-one (IVb). Yield 1.59 g (47%), mp 110–111°C.
1
IR spectrum, ν, cm–1: 1655 (C=C), 1755 (C=O). H
9-(4-Bromophenyl)-7-phenyl-6-oxaspiro[3.5]non-
NMR spectrum, δ, ppm: 6.94–7.53 m (9H, Ph, 4-
ClC6H4), 5.91 d (1H, =CH, J 6.5 Hz), 3.37 d (1H,
ArCH, J 6.5 Hz), 1.20–2.19 m [8H, (CH2)4]. Found,
%: C 74.21; H 5.48; Cl 10.68. C21H19 ClO2. Calculated,
%: C 74.44; H 5.65; Cl 10.46.
7-en-5-one (VIc). Yield 2.59 g (70%), mp 137–138°C.
1
IR spectrum, ν, cm–1: 1675 (C=C), 1760 (C=O). H
NMR spectrum, δ, ppm: 6.97–7.52 m (9H, Ph, 4-
BrC6H4), 5.86 d (1H, =CH, J 6.5 Hz), 3.70 d (1H,
ArCH, J 6.5 Hz), 1.80–2.57 m [6H, (CH2)3]. Found,
%: C 64.89; H 4.52; Br 21.45. C20H17BrO2. Calculated,
%: C 65.05; H 4.64; Br 21.64.
10-(4-Bromophenyl)-8-phenyl-7-oxaspiro[4.5]dec-
8-en-6-one (IVc). Yield 1.63 g (48%), mp 111–112°C.
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 78 No. 7 2008

1424
KIRILLOV, GAVRILOV
7-(4-Bromophenyl)-9-phenyl-6-oxaspiro[3.5]non-
7,9-Bis(4-chlorophenyl)-6-oxaspiro[3.5]non-7-en-
5-one (VIf). Yield 1.34 g (65%), mp 118–119°C. IR
spectrum, ν, cm–1: 1660 (C=C), 1765 (C=O). 1H NMR
spectrum, δ, ppm: 7.59 d, 7.27 d, 7.20 d, 6.91 d (8H, 4-
ClC6H4, 4-ClC6H4, J 8.5 Hz), 5.82 d (1H, =CH, J 6.5 Hz),
3.68 d (1H, ArCH, J 6.5 Hz), 1.74–2.58 m [6H, (CH2)3].
Found, %: C 67.08; H 4.67; Cl 19.4. C20H16 Cl2O2.
Calculated, %: C 66.87; H 4.49; Cl 19.74.
7-en-5-one (VId). Yield 2.59 g (70%), mp 133–134°C.
1
IR spectrum, ν, cm–1: 1645 (C=C), 1740 (C=O). H
NMR spectrum, δ, ppm: 7.10–7.66 m, 6.94 d (9H, Ph,
4-BrC6H4, J 8.4 Hz), 5.81 d (1H, =CH, J 6.5 Hz), 3.65
d (1H, ArCH, J 6.5 Hz), 1.77–2.60 m [6H, (CH2)3].
Found, %: C 65.12; H 4.83; Br 21.91. C20H17 BrO2.
Calculated, %: C 65.05; H 4.64; Br 21.64.
ACKNOWLEDGMENTS
9-(4-Methoxyphenyl)-7-phenyl-6-oxaspiro[3.5]non-
This work was financially supported by the Russian
Foundation for Basic Research (project no. 07-03-
96035).
7-en-5-one (VIe). Yield 2.31 g (72%), mp 89–90°C.
1
IR spectrum, ν, cm–1: 1635 (C=C), 1745 (C=O). H
NMR spectrum, δ, ppm: 7.20-7.67 m, 7.02 d, 6.72 d
(9H, 4-MeOC6H4, Ph, J 8.4 Hz), 5.86 d (1H, =CH, J
6.5 Hz), 3.71 s (3H, MeO), 3.65 d (1H, ArCH, J 6.5 Hz),
1.81-2.55 m [6H, (CH2)3]. Found, %: C 78.48; H 6.11.
C21H20 O3. Calculated, %: C 78.73; H 6.29.
REFERENCE
1. Ocampo, R. and Dolbier, W.R., Terahedron, 2004, vol. 60,
p. 9325.
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 78 No. 7 2008