New Protocol for the Synthesis of 2-Alkanoyl- and 2-Aryloyl-5,5-dimethylcyclohexane-1,3-diones by the Reaction of Dimedone with Various Aldehydes and Cyanogen Bromide in the Presence of Triethylamine

Article abstract of DOI:10.1055/s-0035-1561935

A new route for the synthesis of 2-alkanoyl(aryloyl)-5,5-dimethylcyclohexane-1,3-diones as cyclic β-triketones is described. This synthesis was conducted by the reaction of dimedone with cyanogen bromide and triethylamine to form first the intermediate salt, followed by the addition of various aliphatic and aromatic aldehydes. The structures of the products were characterized by IR, ¹H, and ¹³C NMR spectroscopic techniques. A reaction mechanism is proposed.

Full text of DOI:10.1055/s-0035-1561935

SYNTHESIS
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© Georg Thieme Verlag Stuttgart · New York
2016, 48, A–F
paper
A
E. Kashani et al.
Paper
Synthesis
New Protocol for the Synthesis of 2-Alkanoyl- and 2-Aryloyl-5,5-
dimethylcyclohexane-1,3-diones by the Reaction of Dimedone
with Various Aldehydes and Cyanogen Bromide in the Presence of
Triethylamine
Elmira Kashani
1) BrCN, Et3N, MeOH
Nader Noroozi Pesyan*
Hamid Rashidnejad
O
O
O
O
O
2)
R
H
Department of Organic Chemistry, Faculty of Chemistry,
Urmia University, 57159 Urmia, Iran
n.noroozi@urmia.ac.ir
O
R
nnp403@gmail.com
R = Me, Et, n-Pr, ClCH2, Ph, o-ClC6H4, 2-O2NC6H4,
3,5-(O2N)2C6H3, 2-MeC6H4, 2-HOC6H4
Yields: 45–75%
Received: 02.01.2016
Accepted after revision: 19.02.2016
Published online: 22.03.2016
(compound 3e in this work) has been reported by Tarun et
al.13
Cyclic β-triketones represent useful building blocks for
the synthesis of various heterocyclic compounds due to
their high degree of functionalization and their high reac-
tivity. Heterocycles from the reaction of 2-acylcyclohexane-
1,3-diones with malononitrile are reviewed elsewhere.14
The reaction of 2-formyl- and 2-acetyldimedone with hy-
droxylamine, proceeding through nucleophilic attack at the
exocyclic carbonyl for the formation of an acyloxime inter-
mediate has been used for the synthesis of isoxazoles.15–17
2-Acetyldimedone, condensing with 2 equivalents of hy-
droxylamine, gives rise to oxime isoxazole.15,16 For example,
2-formylcyclohexane-1,3-diones have been reported
through heterocyclic synthesis.18
Some β-triketones such as 3,6-β-dihydroxy-2-(13-
phenyltridecanoyl)-2-cyclohexen-1-one has been obtained
from the natural source of Virola oleifera,19 and the natural
products 2-oleoylcyclohexane-1,3-dione and 4-hydroxy-2-
oleoylcyclohexane-1,3-dione have been extracted from the
larval mandibular glands of Anagasta kuehniella.20 Many
kinds of β-triketones have been synthesized in the labora-
tory through different strategies including 1,3-dipolar cy-
cloaddition of nitrile oxide to cyclohexenone, followed by
the hydrogenation and aqueous hydrolysis, which afforded
2-acylcyclohexane-1,3-diones,21 and from acid anhydrides
(succinic and glutaric anhydrides) and isopropenyl ace-
tate.22 The chemistry of 2-acylcycloalkane-1,3-diones was
reviewed by Rubinov et al.23
DOI: 10.1055/s-0035-1561935; Art ID: ss-2016-z0001-op
Abstract A new route for the synthesis of 2-alkanoyl(aryloyl)-5,5-di-
methylcyclohexane-1,3-diones as cyclic β-triketones is described. This
synthesis was conducted by the reaction of dimedone with cyanogen
bromide and triethylamine to form first the intermediate salt, followed
by the addition of various aliphatic and aromatic aldehydes. The struc-
tures of the products were characterized by IR, 1H, and 13C NMR spec-
troscopic techniques. A reaction mechanism is proposed.
Key words 2-alkanoyl(aryloyl)dimedone, dimedone, cyanogen bro-
mide, aldehyde, cyclic β-triketone, acylation
Among β-triketones, α-acyl-β-diketones are represent-
ed by the 2-acylcyclohexane-1,3-diones and 1,3,5-triones
derivatives. These types of compounds are an important
group of natural products.1,2
2-Aryloylcyclohexane-1,3-dione compounds and their
derivatives have a wide variety of important biological ef-
fects including fungicidal, insecticidal, and insect behavior
controlling activities,3–8 and are an important component in
herbicidal compounds.9–11 For instance, the benzoyl moiety
substituted at the 2-position with groups such as halo or al-
kyl, at the 4-position with an alkylsulfonyl group, and at the
3-position with an acyclic or cyclic derivatized amino group
were prepared and found to be useful in the control of a va-
riety of broad leaf and grassy weeds. These compounds can
be applied either pre-emergently or post-emergently and
can be used to control undesirable vegetation in corn, rice,
and wheat.12 The inhibitory effect of some β-triketones
such as 2-benzoyl-5,5-dimethylcyclohexane-1,3-dione
Due to the importance of α-acyl-β-diketones (as cyclic
β-triketones), we have now synthesized 2-alkanoyl(aryl-
oyl)-5,5-dimethylcyclohexane-1,3-diones 3 by the reaction
of dimedone (1) with cyanogen bromide (BrCN) in the pres-
© Georg Thieme Verlag Stuttgart · New York — Synthesis 2016, 48, A–F

B
E. Kashani et al.
Paper
Synthesis
ence of triethylamine followed by the reaction with aliphat-
ic and aromatic aldehydes as a new synthetic route. There
was no report of this synthetic reaction route in the litera-
ture.
gives 2,6,6-trimethyl-1-oxaspiro[2.5]octane-4,8-dione 6.
The intramolecular rearrangement in 6 affords 3. The re-
sults of these reactions are summarized in Table 1.
Representatively, the 1H NMR spectrum of 3a showed a
singlet at δ = 1.07 (a shoulder on the right side of the peak)
for geminal methyl protons, a singlet at δ = 2.17 (for the
methyl protons of acetyl), and two singlets at δ = 2.23 and
2.37 (the latter had a shoulder on the left side of the peak)
for two methylene protons of dimedone ring moiety. Ap-
parently a singlet at δ = 5.87 corresponded to a CH proton.
Essentially this peak was not a singlet and showed three
singlets at δ = 5.861, 5.865, and 5.869. The expanded peak
of CH is shown in Figure 1. 13C NMR spectrum of this com-
pound showed three peaks for carbonyl groups at δ = 199.4,
168.0, and 167.4 and surprisingly, five distinct peaks for CH
carbon atom at δ = 117.9, 117.0, 116.4, 115.9, and 115.0. It
seems that two methyl groups have non-equivalent chemi-
cal shifts on dimedone ring moiety and this was also true
Thus, this paper describes a new synthetic route for 2-
alkanoyl(aryloyl)-5,5-dimethylcyclohexane-1,3-diones 3.
The reaction of dimedone (1) with BrCN in the presence of
triethylamine and subsequently with various aldehydes 2
afforded 3 in two steps (Scheme 1). The reaction mecha-
nism for the synthesis of 3 is shown in Scheme 2. First, the
reaction of dimedone (1) with BrCN and triethylamine
gives the salt of triethylammonium 1-bromo-4,4-dimethyl-
2,6-dioxocyclohexan-1-ide (4).24 The reaction mechanism
and structural elucidation of 4 is already described by our
research group.24 The nucleophilic attack of 4 to the carbon-
yl group in 2 produces the intermediate 5, then intramolec-
ular nucleophilic attack of oxygen anion to carbon atom
containing bromine atom (pushing the bromide ion out)
1
for the two methylene groups. The comparison of the H
and 13C NMR peaks of CH in 3a and 3e is shown in Figure 1.
1) BrCN, Et3N, MeOH
2) RCHO (2)
O
O
O
O
1
O
R
a R = Me
b R = Et
f R = o-ClC6H4
g R = 2-O2NC6H4
3
c R = n-Pr
d R = ClCH2
e R = Ph
h R = 3,5-(O2N)2C6H3
i R = 2-MeC6H4
j R = 2-HOC6H4
Scheme 1
1) BrCN, Et3N
MeOH
O
O
O
O
Br
1
Et3NH
O
R
4
DMF
2
Et3NH
O
O
Br
O
R
5
– Et3NHBr
O
O
O
O
O
O
R
R
Figure 1 The expanded peaks of CH proton in 1H NMR (a) and CH car-
bon atom in 13C NMR spectrum (b) in 3a, and 1H NMR (c) and 13C NMR
spectrum (d) of 3e
H
3
6
Scheme 2
© Georg Thieme Verlag Stuttgart · New York — Synthesis 2016, 48, A–F

C
E. Kashani et al.
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Synthesis
Interestingly, when this reaction was carried out as a
one-pot reaction, 4′,4′,6,6-tetramethyl-3-(alkyl and/or
aryl)-3,5,6,7-tetrahydrospiro[benzofuran-2(4H),1′-cyclo-
hexane]-2′,4,6′-trione 7 was obtained as the sole product.24
In contrast, when we prepared and separated the salt 4 (see
Scheme 2) its reaction with aldehydes 2 gave 2-al-
kanoyl(aryloyl)-5,5-dimethylcyclohexane-1,3-diones 3 in
good yields (Scheme 3).
two steps
1) BrCN, Et3N, MeOH
O
O
2) RCHO
O
R
2
3
Aldehydes consisting of strong electron-donor substitu-
ents did not give the cyclic β-triketones 3 under the same
conditions. Strong electron-donor substituents inactivate
the aldehyde carbonyl group by resonance effect25 (Table 1,
entries 11–14). We examined the reaction of acetone as a
ketone with the salt 4 under the same conditions and ob-
served that no reaction occurred probably due to the hin-
drance effect of ketone compared to aldehyde (entry 15).
O
O
1
O
O
O
one-pot
R
O
BrCN, Et3N,
RCHO (2), MeOH
7
Scheme 3
Table 1 Reaction of Dimedone (1) with Various Aldehydes 2 Producing Cyclic β-Triketones 3 via the Salt 4
Entry
Aldehyde 2
Cyclic β-triketone 3
Mp (°C)
3622,26
Yield (%)
50
O
O
1
2a
MeCHO
EtCHO
3a
3b
3c
3d
O
O
O
2
3
4
2b
2c
2d
4826
50
40
15
Et
O
O
O
O
n-PrCHO
ClCH2CHO
6926
n-Pr
O
Cl
a26
–
O
O
O
O
a26
5
6
2e
2f
3e
3f
–
75
75
CHO
O
O
O
Cl
Cl
a26
–
CHO
O
© Georg Thieme Verlag Stuttgart · New York — Synthesis 2016, 48, A–F

D
E. Kashani et al.
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Synthesis
Table 1 (continued)
Entry
7
Aldehyde 2
Cyclic β-triketone 3
Mp (°C)
11826
Yield (%)
O
O
O
NO2
O2N
2g
2h
2i
3g
3h
3i
45
50
75
45
CHO
O
O
O
O2N
O2N
8
9
CHO
13026
O2N
NO2
O
O
12026
CHO
O
O
O
OH
HO
a26
10
2j
3j
–
CHO
O
11
12
13
2k
2l
NRb
NR
NR
–
–
–
–
–
–
HO
CHO
MeO
N
CHO
2m
CHO
CHO
14
15
2n
2o
NR
NR
–
–
–
–
N
H
O
a A viscous solid was obtained. Many of these compounds are commercially available.
b NR: No reaction.
In summary, a new route has been introduced for the
synthesis of 2-alkanoyl(aryloyl)-5,5-dimethylcyclohexane-
1,3-diones 3 as cyclic β-triketones. This is conducted by the
reaction of dimedone (1) with cyanogen bromide and tri-
ethylamine to form the salt 4, followed by the addition of
various aliphatic and aromatic aldehydes 2. Aliphatic and
aromatic aldehydes including electron-withdrawing sub-
stituents formed cyclic β-triketones. Aromatic aldehydes
including strong electron-donor substituents did not form
cyclic β-triketones.
The drawing and nomenclature of the compounds were done by
ChemDraw Ultra version 8.0. Melting points were measured with a
digital melting point apparatus (Electrothermal) and are uncorrected.
IR spectra were recorded in the region 4000–400 cm–1 on a NEXUS
670 FT IR spectrometer by preparing KBr pellets. The 1H and 13C NMR
spectra were recorded on Bruker 300 FT-NMR at 300 and 75 MHz, re-
spectively (Urmia University, Urmia, Iran). 1H and 13C NMR spectra
were recorded in CDCl3 using TMS as internal standard. Standard ab-
breviations were used to denote the signal multiplicities. Coupling
constants are in hertz. All reactions were monitored by TLC with sili-
ca gel-coated plates. BrCN was synthesized based on the literature re-
port.27 Compounds 1, 2, Et3N, and solvents were purchased from Merck
and Aldrich and used without further purification.
© Georg Thieme Verlag Stuttgart · New York — Synthesis 2016, 48, A–F

E
E. Kashani et al.
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Synthesis
Triethylammonium 2-Bromo-5,5-dimethylcyclohexane-1,3-di-
one-2-ide (4)24
13C NMR (75 MHz, CDCl3): δ = 199.1 (C=O), 170.1 (C=O), 168.1 (C=O),
117.65, 116.83, 116.30, 116.21, 115.68, 114.87 [CH(C=O)3], 50.68,
42.09 (COCH2), 36.09, 36.03 (COCH2CH2CH3), 32.98 [C(CH3)2], 28.71,
27.29 [C(CH3)2], 17.98, 16.77 (COCH2CH2CH3), 14.16 (COCH2CH2CH3),
12.54 (COCH2CH2CH3).
In a 25 mL round bottom flask equipped with a magnetic stirrer was
placed BrCN (106 mg, 1.0 mmol) in MeOH (5 mL) and the flask was
immersed in an ice-bath. In a separate vessel, dimedone (1; 140 mg,
1.0 mmol) and Et3N (101 mg, 1.0 mmol) were dissolved in MeOH (5
mL). Then, the latter solution was added dropwise to the solution of
BrCN at 0 °C. The salt 4 formed was collected by suction filtration;
yield: 223 mg (70%); colorless crystalline solid; mp 75–76 °C.
2-(2-Chloroacetyl)-5,5-dimethylcyclohexane-1,3-dione (3d)
Yield: 0.032 g (15%); brown viscous solid.
FT-IR (KBr): 2941, 1736, 1663, 1451, 1375, 1235, 1123, 744 cm–1
.
FT-IR (KBr): 3417, 2958, 2870, 2678, 2495, 1644, 1610, 1509, 472 cm–1
.
1H NMR (300 MHz, CDCl3): δ = 1.11 [s, 6 H, C(CH3)2], 1.83 (m, 2 H, CO-
CH2), 2.24–2.46 (m, 4 H, COCH2 and COCH2Cl), 5.98 [s, 1 H, CH(C=O)3].
13C NMR (75 MHz, CDCl3): δ = 198.2 (C=O), 177.2 (C=O), 116.4, 111.7
[CH(C=O)3], 75.9, 62.2 (COCH2Cl), 50.6 (COCH2), 34.3 (COCH2), 29.02
[C(CH3)2], 27.8, 27.5 [C(CH3)2].
1H NMR (300 MHz, CDCl3): δ = 0.87 [s, 6 H, C(CH3)2], 1.17 [t, J = 7.5 Hz,
(CH3CH2)3NH+, 9 H], 2.18 (s, 4 H, 2 × CH2CO), 3.02 [q, J = 7.5 Hz,
(CH3CH2)3NH+, 6 H], 7.27 (br s, 1 H, (CH3CH2)3NH+].
13C NMR (75 MHz, CDCl3): δ = 186.0 (C=O), 96.7 (CBr), 50.2
[(CH3CH2)3NH+], 46.2 (CH2CO), 31.7 [C(CH3)2], 28.3 [C(CH3)2], 8.7
(CH3CH2)3NH+).
2-Benzoyl-5,5-dimethylcyclohexane-1,3-dione (3e)
Yield: 0.183 g (75%); brown viscous solid.
FT-IR (KBr): 3068, 2956, 2886, 1742, 1668, 1365, 1250, 1120, 703 cm–1
2-Alkanoyl(aryloyl)-5,5-dimethylcyclohexane-1,3-diones 3; Gen-
eral Procedure
.
1H NMR (300 MHz, CDCl3): δ = 1.086, 1.080 [2 s, 6 H, C(CH3)2, over-
lapped], 2.25 (s, 2 H, COCH2), 2.49 (s, 2 H, COCH2), 5.99 [s, 1 H,
CH(C=O)3], 7.42 (t, J = 7.2 Hz, 2 Harom), 7.57 (t, J = 7.2 Hz, 1 Harom), 8.01
(d, J = 7.2 Hz, 2 Harom).
13C NMR (75 MHz, CDCl3): δ = 199.2 (C=O), 168.4 (C=O), 163.2 (C=O),
134.97, 133.20, 131.15, 131.08, 129.78, 129.70, 129.19, 129.11,
128.68, 128.60, 127.65, 127.58 (C6H5), 118.13, 117.72, 117.16, 116.75,
116.69, 116.28, 115.73, 115.32 [CH(C=O)3], 50.8, 42.2 (COCH2), 33.2
[C(CH3)2], 28.9, 27.4 [C(CH3)2].
In a 25 mL round bottom flask equipped with a magnetic stirrer was
placed the salt 4 (321 mg, 1.0 mmol) and dissolved immediately in
DMF (5 mL). Aldehyde 2 (1.0 mmol) was then added and the reaction
mixture was stirred for 24 h. The reaction progression was monitored
by TLC [eluent: n-hexane–EtOAc (3:1, v/v)]. After completion of the
reaction, H2O was added, the mixture was extracted with EtOAc (3 × 2
mL), and the combined organic layers were washed with brine. The
organic phase was dried with Na2SO4, filtered, and the solvent was
evaporated. The solvent was removed under reduced pressure, the
residue was washed with cold EtOH, and dried.
2-(2-Chlorobenzoyl)-5,5-dimethylcyclohexane-1,3-dione (3f)
Yield: 0.209 g (75%); brown viscous solid.
2-Acetyl-5,5-dimethylcyclohexane-1,3-dione (3a)
Yield: 0.091 g (50%); brown solid; mp 36 °C.
FT-IR (KBr): 2956, 2888, 1770, 1669, 1365, 1189, 1118 cm–1
FT-IR (KBr): 3073, 2956, 2886, 1750, 1668, 1441, 1365, 1276, 1236,
1119, 1024, 741 cm–1
.
.
1H NMR (300 MHz, CDCl3): δ = 1.065, 1.060 [2 s, 6 H, C(CH3)2, over-
lapped], 2.17 (s, 3 H, COCH3), 2.23 (s, 2 H, COCH2), 2.37 (s, 2 H, COCH2),
5.861, 5.865, 5.869 [3 s, 1 H, CH(C=O)3].
1H NMR (300 MHz, CDCl3): δ = 1.116, 1.132 (2 s, 6 H, C(CH3)2), 2.297
(s, 2 H, COCH2), 2.532 (s, 2 H, COCH2), 6.02 [s, 1 H, CH(C=O)3], 7.31–
7.36 (m, 1 Harom), 7.46 (d, J = 3.9 Hz, 2 Harom), 7.89 (d, J = 7.5 Hz, 1 Harom).
13C NMR (75 MHz, CDCl3): δ = 199.4 (C=O), 168.0 (C=O), 167.4 (C=O),
117.6, 117.0, 116.4, 115.9, 115.0 [CH(C=O)3], 50.7, 42.2 (COCH2), 33.1
[C(CH3)2], 28.8, 27.4 [C(CH3)2].
13C NMR (75 MHz, CDCl3): δ = 199.2 (C=O), 168.1 (C=O), 161.9 (C=O),
134.86, 134.75, 134.50, 133.09, 133.06, 132.62, 132.58, 130.99,
130.94, 130.39, 130.34, 127.88, 125.85, 125.81 (CHarom and Carom),
118.31, 117.93, 117.32, 116.94, 116.88, 116.50, 115.51 [CH(C=O)3],
50.9 (COCH2), 42.1 (COCH2), 33.2 [C(CH3)2], 28.9, 27.4 [C(CH3)2].
5,5-Dimethyl-2-propionylcyclohexane-1,3-dione (3b)
Yield: 0.098 g (50%); brown solid; mp 48 °C.
FT-IR (KBr): 2958, 2889, 1768, 1671, 1358, 1121 cm–1
2-(2-Nitrobenzoyl)-5,5-dimethylcyclohexane-1,3-dione (3g)
Yield: 0.130 g (45%); white solid; mp 118 °C.
.
1H NMR (300 MHz, CDCl3): δ = 1.05 [2 s, 6 H, C(CH3)2, overlapped],
1.14 (t, J = 7.5 Hz, CH3CH2, 3 H), 2.21 (s, 2 H, COCH2), 2.36 (s, 2 H, CO-
CH2), 2.44 (q, J = 7.5 Hz, CH3CH2, 2 H), 5.84 [3 s, 1 H, CH(C=O)3].
13C NMR (75 MHz, CDCl3): δ = 199.3 (C=O), 171.0 (C=O), 168.2 (C=O),
117.746, 116.889, 116.309, 115.733, 114.873 [CH(C=O)3], 50.75, 42.15
(COCH2), 33.05 (COCH2CH3), 28.77 [C(CH3)2], 27.76, 27.34 [C(CH3)2],
9.40, 7.94 (COCH2CH3).
FT-IR (KBr): 3086, 2956, 2880, 1757, 1672, 1536, 1358, 1247, 1116,
1046 cm–1
.
1H NMR (300 MHz, CDCl3): δ = 1.16 [s, 6 H, C(CH3)2], 2.33 (s, 2 H, CO-
CH2), 2.58 (s, 2 H, COCH2), 6.06 [s, 1 H, CH(C=O)3], 7.73–7.80 (m, 3
Harom), 8.04 (d, J = 7.2 Hz, 1 Harom).
13C NMR (75 MHz, CDCl3): δ = 199.13 (C=O), 167.76 (C=O), 162.23
(C=O), 147.00, 132.58, 132.35, 131.62, 131.27, 131.19, 129.14, 125.31,
123.29 (CHarom and Carom), 118.43, 118.09, 116.99, 116.66, 115.62
[CH(C=O)3], 50.91 (COCH2), 41.26 (COCH2), 33.25 [C(CH3)2], 28.87,
27.43 [C(CH3)2].
5,5-Dimethyl-2-butanoylcyclohexane-1,3-dione (3c)
Yield: 0.084 g (40%); brown solid; mp 69 °C.
FT-IR (KBr): 2958, 2887, 1766, 1672, 1362, 1121 cm–1
.
1H NMR (300 MHz, CDCl3): δ = 0.87 (t, J = 7.5 Hz, CH3CH2CH2, 3 H),
0.99 [2 s, 6 H, C(CH3)2, overlapped], 1.59 (sext, J = 7.2 Hz, CH3CH2CH2,
2 H), 2.14 (s, 2 H, COCH2), 2.29 (s, 2 H, COCH2), 2.33 (t, J = 7.2 Hz,
CH3CH2CH2, 3 H), 5.76 [3 s, 1 H, CH(C=O)3].
2-(3,5-Dinitrobenzoyl)-5,5-dimethylcyclohexane-1,3-dione (3h)
Yield: 0.167 g (50%); white solid; mp 130 °C.
© Georg Thieme Verlag Stuttgart · New York — Synthesis 2016, 48, A–F

F
E. Kashani et al.
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Synthesis
FT-IR (KBr): 3096), 2947, 2887, 1748, 1665, 1542, 1346, 1263, 1144,
725 cm–1
1H NMR (300 MHz, CDCl3): δ = 1.20 [s, 6 H, C(CH3)2], 2.37 (s, 2 H, CO-
CH2), 2.60 (s, 2 H, COCH2), 6.12 [s, 1 H, CH(C=O)3], 9.21 (d, J = 1.8 Hz, 2
Supporting Information
.
Supporting information for this article is available online at
http://dx.doi.org/10.1055/s-0035-1561935. Spectroscopic data are
supplied for compounds 3a–j.
S
u
p
p
ortiInfogrmoaitn
S
u
p
p
ortioInfgrmoaitn
H
arom), 9.30 (dd, J = 2.1, 1.8 Hz, 1 Harom).
13C NMR (75 MHz, CDCl3): δ = 198.63 (C=O), 167.00 (C=O), 159.50
(C=O), 148.86, 132.42, 130.89, 129.91, 129.74, 128.76, 123.34, 123.20
(CHarom and Carom), 119.02, 118.71, 117.59, 116.47, 116.16 [CH(C=O)3],
50.79 (COCH2), 42.05 (COCH2), 33.37 [C(CH3)2], 28.90, 27.46 [C(CH3)2].
References
(1) Hassall, C. H. In Progress in Organic Chemistry; Vol. 4; Cook, J.
W., Ed.; New York: Academic Press, 1958, 115–139.
(2) Forsen, S.; Nilsson, M. Acta Chem. Scand. 1959, 13, 1383.
(3) Akhrem, A. A.; Lakhvich, F. A.; Budai, S. I.; Khelebnicova, T. S.;
Petrusevich, I. I. Synthesis 1978, 925.
(4) Mudd, A. J. Chem. Soc., Perkin Trans. 1 1981, 2357.
(5) Mudd, A. J. Chem. Soc., Perkin Trans. 1 1983, 2161.
(6) Mudd, A.; Corbet, S. A. J. Chem. Ecol. 1982, 8, 843.
(7) Mudd, A.; Walters, J. H. H.; Corbet, S. A. J. Chem. Ecol. 1984, 10,
1597.
2-(2-Methylbenzoyl)-5,5-dimethylcyclohexane-1,3-dione (3i)
Yield: 0.193 g (75%); brown solid; mp 120 °C.
FT-IR (KBr): 3065, 2958, 2888, 1742, 1670, 1460, 1369, 1234, 1119,
1023, 739 cm–1
.
1H NMR (300 MHz, CDCl3): δ = 1.08 [s, 6 H, C(CH3)2], 2.24 (s, 2 H, CO-
CH2), 2.48 (s, 2 H, COCH2), 2.61 (s, 3 H, ArCH3), 5.97 [s, 1 H, CH(C=O)3],
7.22 (m, 2 Harom), 7.39 (s, J = 7.8 Hz, 1 Harom), 7.93 (d, J = 7.8 Hz, 1
(8) Mudd, A. J. Chem. Ecol. 1985, 11, 51.
H
arom).
(9) Seitz, T.; Willms, L.; van Almsick, A.; Bieringer, H.; Auler, T.;
Menne, H. US Patent 6,774,086 B2, 2004.
(10) Seitz, T.; van Almsick, A.; Willms, L.; Schmitt, M. H.; Auler, T.;
Bieringer, H.; Menne, H. US Patent 6,930,208 B2, 2005.
(11) van Almsick, A.; Willms, L.; Hacker, E.; Bieringer, H. Patent
6,576,593 B2, 2003.
(12) Laszlo, B. Z.; Arzie, T. J. US Patent WO1998042648 A1, 1998.
(13) Tarun, E. I.; Rubinov, D. B.; Metelitza, D. I. Appl. Biochem. Micro-
biol. 2004, 40, 337.
(14) (a) Fatiadi, A. J. Synthesis 1974, 165. (b) Fatiadi, A. J. Synthesis
1974, 241.
(15) Crossley, W.; Renouf, N. J. Chem. Soc. 1912, 101, 1524.
(16) Smith, H. J. Chem. Soc. 1953, 803.
(17) Ablovatskaya, M. V.; Gudriniece, E. Y.; Strakov, A. Y. Latv. PSR
Zinat. Akad. Vestis, Khim. Ser. 1989, 601; Chem. Abstr. 1990, 112,
178751q.
(18) Strakov, A. Y.; Gudriniece, E. Y.; Strakova, I. A. Khim. Heterocycl.
Soed. 1988, 723; Chem. Abstr. 1989, 110, 154173k.
(19) Azevedo, N. R.; Santos, S. C.; De Miranda, E. G.; Ferri, P. H. Phyto-
chemistry 1997, 46, 1375.
(20) Mudd, A. J. Chem. Soc., Chem. Commun. 1978, 1075.
(21) Akhrem, A. A.; Lakhvich, F. A.; Khripach, V. A.; Klebanovich, I. B.
Khim. Geterotsikl. Soedin. 1975, 4, 329.
13C NMR (75 MHz, CDCl3): δ = 199.06 (C=O), 168.47 (C=O), 163.56
(C=O), 141.52, 141.44, 134.32, 134.28, 134.23, 133.06, 132.21, 132.13,
131.04, 130.23, 130.15, 127.43, 127.03 (CHarom and Carom), 118.09,
117.64, 117.22, 116.77, 116.65, 116.20, 115.34 [CH(C=O)3], 50.82 (CO-
CH2), 42.26, 41.19 (COCH2), 33.13 [C(CH3)2], 28.87, 27.39 [C(CH3)2],
21.92 (ArCH3).
2-(2-Hydroxybenzoyl)-5,5-dimethylcyclohexane-1,3-dione (3j)
Yield: 0.117 g (45%); brown viscous solid.
FT-IR (KBr): 3460, 3243, 3075, 2956, 2888, 1744, 1682, 1610, 1475,
1283, 1246, 1204, 1119, 1042, 751 cm–1
.
1H NMR (300 MHz, CDCl3): δ = 0.91, 0.98 [2 s, 6 H, C(CH3)2, the peak at
0.98 ppm has a shoulder at the peak’s left side), 2.18–2.33 (m, 4 H, 2 ×
COCH2), 5.92 [s, 1 H, CH(C=O)3], 6.98–8.24 (m, 4 Harom), 10.29 (s, 1 H,
OH).
13C NMR (75 MHz, CDCl3): δ = 199.35, 199.15 (C=O), 168.69, 168.02
(C=O), 162.51, 162.01, 161.11, 160.95 (C=O), 150.48 (ArC–OH),
137.46, 135.90, 135.39, 133.53, 131.59, 129.72, 129.62, 127.92,
127.34, 125.38, 123.16, 122.53, 122.32 (CHarom and Carom), 120.42,
118.62, 118.16, 117.30, 116.79, 116.17, 115.36 [CH(C=O)3], 51.23 (CO-
CH2), 41.94 (COCH2), 33.01 [C(CH3)2], 28.66, 27.25 [C(CH3)2].
(22) Nilsson, M.; Merényi, F. Acta Chim. Scand. 1964, 18, 1368.
(23) Rubinov, D. B.; Rubinova, I. L.; Akhrem, A. A. Chem. Rev. 1999, 99,
1047.
Acknowledgment
(24) Noroozi Pesyan, N.; Shokr, A.; Behroozi, M.; Şahin, E. J. Iran.
Chem. Soc. 2013, 10, 565.
We gratefully acknowledge financial support from the Research
Council of Urmia University.
(25) Adamson, J.; Coe, B. J.; Grassam, H. L.; Jeffery, J. C.; Coles, S. J.;
Hursthouse, M. B. J. Chem. Soc., Perkin Trans. 1 1999, 2483.
(26) http://www.chemicalbook.com/ChemicalProductProper-
ty_EN_CB2415765.htm (accessed date: 12/27/2015).
(27) Hartman, W. W.; Dreger, E. E. Org. Synth. Coll. Vol. 2; Wiley: New
York, 1943, 150.
© Georg Thieme Verlag Stuttgart · New York — Synthesis 2016, 48, A–F