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Bull.
SOC.
Chim. Belg. vo1.94/n0 5/1985
REARRANGEMENT OF 2-ACYL-2-CHLORO-l,3-CYCLOHEXANEDIONES INTO
2-ACYLRESORCINOLS AND Z-ACYL-4-CHLORO-1.3-CYCLOHEXANEDIONES
L. De Buyck, D. Seynaeve, N. De Kimpe. R. Verhe and N. Schamp
Laboratory of Organic Chemistry, Faculty of Agricultural Sciences,
State University of Ghent, Coupure Links 653, B-9000 GHENT (BELGIUM)
Received : 13/05/1985 - Accepted : 01/07/1985
Abstract
2-Acetylresorcinol was prepared in 8 0 - 8 8 % yield from 2-acetyl-1.3-cyclohexanedione by 2-chlorination (excess of NCS in boiling carbon tetrachloride
or one equivalent of molecular chlorine in the cold solvent) followed by aromatization in a heated dry solution of hydrogen chloride in dimethylformamide.
The scope of the method was extended to the preparation of 2-propionyl- and
2-isobutyrylresorcinol (resp. 79% and 66% yield). Application of the method
on 2-acyl-5,5-dimethyl-l,3-cyclohexanediones (acyl
acetyl, propionyl, n-butyryl. i-butyryl) afforded the corresponding 2-acyl-4-chlorodimedone derivatives is 40-771 yields.
-
Introduction
2-Acetylresorcinol (1) has become a valuable intermediate in pharmaceutical chemistry, especially a s a building block for the manufacture of a drug
which is very effective in treatment of asthma.’ * 5 Fries rearrangement of 7 acetoxy-4-methylcoumarin is commonly used in current preparations of 1.2’3’4
In 1973 we reported6 an original synthesis of 1 according to Scheme I . Recently two companies informed us about considerable difficulties they met when
trying to reproduce our result. It was even put in doubt from one side whether
the 2-chlorination of 2-acetyl-1.3-cyclohexanedione (1)was feasible at all,
using N-chlorosuccinimide or another chlorinating agent.
aon
- go-
.*p
1
0
0
&:’
R2
2 Rl-H R2=Me
-4 Rl-H R2=Et
-7 R l = H R2=d.Pr
10 R 1 = R2=Me
13 Rl=Me R2=Et
16 Rl=Me R2-t-Pr
0
-3
R2
Rl-H R2=Me
R l = H R2=Et
R1=H R2=L-Pr
Rl=R2=Me
Rl=Me R2=Et
Rl=Me R2=t-Pr
2 0 Rl=Me R2-i-Pr
5
8
11
14
17
no
O
HO
R2
(63-77%)
-1 RZ=Me ( 8 0 - 8 8 % )
15
R2=Et
(54%)
6 R2=Et (79%)
18 R2-;-Pr
(401)
9 R2=i-Pr (66%)
21 R2=i-Pr (611)
(overall yields)
SCHEME I
By this report we present not only an improved and more detailed version
of our synthesis of 1. but we also extend the scope of the reaction using other
acyl groups and demonstrate the related rearrangement of 2-acetyl-2-chlorodimedones into the corresponding 2-acyl-4-chloroderivatives, which is accompanied
with very little aromatization. The preparative importance of our reaction
19 Rl=Me R,=i-Pr
-
12 R2=Me
363
-
sequence is further supported by a considerable progress in the synthesis o f
a variety o f 2-acyl-l,3-cyclohexanediones as suitable starting
Related rearrangements o f 2.2-dichlorinated dimedone derivatives have
been shown t o involve a n allylic rearrangement in the enol form, while the corresponding bromoderivatives tend to suffer a less selective debromination-rebromination mechanism in the presence o f hydrogen halide.''
Although cationic
chlorine could be generated quite readily from a C-Cl bond activated by three
carbonyl groups as in 3, 11 etc., the lack o f reduction- or dichlorination product detected after rearrangement o f very pure 11 still indicates the exclusive operation o f an enol ally1 chloride mechanism.
material^.^*^'^
2-Chlorination of 2-Acyl-1,3-cyclohexanediones
Introduction of a 2-chlorosubstituent in 2-acetyl-1,3-cyclohexanedione
(2) is possible with a n excess o f N-chlorosuccinimide in boiling carbon tetrachloride a s described 6 or with the calculated dose o f chlorine in cold carbon
tetrachloride. A very reliable and practically quantitative conversion into
3 was obtained from 10% solutions o f 2 in the dry a g d - a i c g h g l ~ f r g g solvent
after 4 h o f boiling in the presence o f 2 equivalents of NCS. A n almost equally good yield, at least o n a 0.1 to 0.3 mol scale, resulted from rapid addition of chlorine (0.98-1.00 equiv.; 8 - 1 0 1 in carbon tetrachloride) to a cold
solution of 2. Any excess o f halogen was easily consumed by further chlorination in the 4-position.
With longer acyl groups and with dimedone derivatives the NCS method
and showed less selecw a s more time-consuming (7 h for 95% conversion o f 9)
tivity ( 5 - 1 0 % a-chlorination in the side chain and in the 4-position). Better
results were then obtained with direct chlorination. A brief excess o f chlorine was even allowable in the case o f dimedone derivatives.
I t is recommended that the 2-acyl-2-chloro-1.3-cyclohexanediones be used
immediately after evaporation in vacuo. They are relatively stable to heat
(lOO°C) and c a n be kept unchanged for weeks in a freezer. but they are rapidly
degraded by water and the lower alcohols (Scheme 1 1 ) . With methanol ( 1 5 % in
CDCIJ at 3SoC, 2 : l proportion to substrate) the dimedone derivatives showed
only loss o f the acyl group to form 2-chlorodimedone (22) (60% in 2 h from the
acetyl derivative 11;60% in 2 0 h from the i-butyrylderivative to). Under
those conditions 2 was completely degraded in 15 min mainly by ring opening to
afford 2 and a little of 23.
23 R l = H
-
24 R=Me,
-
SCHEME I 1
-
364
-
R2=Et
Rearrangement and Aromatization
The rearrangement conditions (12O-13O0C for 1 5 - 2 0 min in 10-20% hydrogen
chloride-dimethylformamide) are essentially the same as described.6 Considering the risk of degradation reactions a good (dry) grade of DMF seems neceswas observed
sary. Typically 121 of degradation into 2-chlorodimedone
when the rearrangement of acetylderivative 11 was performed with the fivefold
weight of reagent prepared from fresh commercial 991 DMF and hydrogen chloride
from a gas cyclinder.
(z)
60
11
-
25
-
min
12
-
SCHEME 111
Careful analysis of the reaction mixture from 11 (most extensively studied)
revealed the presence of about 5 t (41 isolated) of the aromatization product
2 5 (Scheme 1 1 1 ) .
This material was found not to arise from 11 as a precursor,
under acid or basic conditions that may cause aromatization of 2.4-dichlorodimedone.6 We therefore propose that 25 is derived from the bis-enolized intermediate (Scheme I ) which also could be the precursor for a large part of 11.
since rearrangement of chloride in bis-enolized related systems can occur without appreciable aromatization. 10
2-Acyl-4-chlororesorcinols were found as side products by rearrangement
of material contaminated with 2-acyl-2,4-dichloro-l,3-cyclohexanediones. Rearrangement of 2.4-dichlorinated acyldimedone derivatives gave rise to 2-acyl4,6-dichlorodimedone derivatives (26, 11) and about equal amounts of the degradation product 2.4-dichlorodimedone (Scheme I V ) .
26 R 2 = M e
2 1 R2=Et
SCHEME I V
Experimental and Spectral Data
Varian T-60 ('H-60MHz) and Var an FT-80 (13C-ZOMHz) apparatus were used
for obtaining NMR-spectra (internal TMS). Unresolved long range couplings
are indicated by * . Infrared spect a were run on a Perkin Elmer 1310 spectrophotometer.
-
365
-
Chlorination with NCS
2-Acetyl-2-chloro-l,3-cyclohexanedione ( 5 )
A solution of 2-acetyl-1,3-cyclohexanedione (2) (38.5 g; 0 . 2 5 mol) in
380 ml of carbon tetrachloride (dried by azeotropic distillation) was stirred
and boiled with 6 7 g ( 0 . 5 mol) of air-dried NCS during 4 h (951 conversion after 3 h). After standing at 20°C for 1 h the precipitate was filtered and
washed (3 x 6 0 ml of CC14).
The solution was evaporated in vacuo and immediately used in the rearrangement procedure.
36 m.p. 4 l o C (cold CC14-hexane)
H' NMR (CDC13) : 6 2.07 (2H) m ; 2.31 (3H) s; 2.90 (4H) m.
13C NMR (CDC13) : 6 16.8 t m 130Hz corr. 6 2.07; 26.2 q 130.5Hz c o w . 6 2.31;
38.7 t m 130Hz corr. 6 2.90; 88.7 s br. s; 196.2 m d 6.8Hz 3.5Hz; 196.3 q 6.5Hz.
Application o f the procedure on the isobutyrylderivative 1 (5 h of boiling)
afforded (NMR-analysis) 581 of starting material, 5 5 1 of A and 7% of 2-chloro2-(2-chloro-2-methylpropanoyl)-l,3-cyclohexanedione (signal 6 1.75).
Applied
on lo (7 h boiling period) 951 conversion into fl was obtained.
Direct Chlorination
2-Acetyl-2-chloro-5,5-dimethyl-1,3-cyclohexanedione (11)
a) Excess method : A solution of 48.4 g (0.266 mol) of 2-acetyldimedone (lo)
in dry carbon tetrachloride (400 ml) was stirred and cooled (iced brine).
Chlorine gas was introduced to obtain a visible excess in 5 min (pale
yellow color and evolution of hydrogen chloride). The solution was evaporated in vacuo immediately. N.M.R. analysis showed less than 21 of dichlorination. Overchlorination was strongly enhanced by catalytic amounts of
added DMF.
b) Adjusted dose (preferred method for cyclohexanediones) : T o 36.4 g ( 0 . 2 0
mol) of 3 in 8 0 ml of carbon tetrachloride, stirred and cooled in iced
brine, was added in 1 min a solution of 14 g (0.197 mol) of chlorine in
149 ml of carbon tetrachloride. The solution was evaporated immediately
in vacuo.
1 1 m.p. 7 O o C (hexane); I . R . (KBr) : 1760. 1728 cm-l
'H NMR (CDC13) : 6 0.90 (3H) s**; 1.19 (3H) s*; 2.40 (3H) s; 2.80 (2H) d 14Hz;
2.88 (ZH) d 14Hz.
13C NMR (CDC13) : 6 26.3 q 130.4Hz corr. 6 2.40; 27.1 q br. m 126Hz c o n .
6 0.90; 29.1 q br. m 126Hz c o n . 6 0.90; 29.1 q br. m l26Hz corr. 6 1.19; 30.0
m 3.9Hz; 52.3 t m 131.5Hz 4.4Hz corr. 6 2.80-2.88; 88.4 s (br.); 195.6 t 6.6Hz;
196.4 q 6.4Hz.
-5
(cold CC14).
2-Chloro-2-propionyl-l,3-cyclohexanedione. m.p. 89'C
(KBr) : 1755; 1715 cm-'.
'H NMR (CDC13) : 6 1.03 (3H) t 7Hz; 1.6-2.3 (2H) m; 2.68 (2H) q 7Hz; 2.88
(4H) dd 7Hz S.5Hz.
13C NMR (CDC13) : 6 8.0 q t 128.7Hz 4.1Hz corr. 6 1.03; 16.9 t m 132Hz corr.
6 1.6-2.3; 32.3 t q 127.5Hz 4.2Hz c o n . 6 2.68; 38.7 t m 127.5Hz corr. 6 2.88;
88.5 s (m); 196.2 s (m) (2 x 0 0 ) ; 199.4 m 5.4Hz. After ring opening with
methanol : Methyl 6-chloro-5.7-dioxononanoate (2)
: (largely enolized)
I.R.
-
366
-
'H NMR (CDC13) : 6 1.13 (3H) t 7Hz; 1.98 (2H) m 2.2
s ; 14.8 (1H) v br. s .
13C NMR (CDC13) : 6 8.7 q t 128.4Hz 4.5Hz corr. 6 1.
corr. 6 1.98; 29.9 t q 128.2Hz 4.1Hz; 33.1 t m 30H2
4.3Hz; 51.5 q 146.6Hz corr. 6 3.65; 107.4 s (br ) ; 1
5.6Hz 3.7Hz; 192.8 m 5.4Hz.
2.8 (6H) m; 3.65 (3H)
3; 20.1 t m 128Hz 4.8Hz
4.4Hz; 35.0 t m l28Hz
3.3 m 3.7Hz; 189.6 t t
8 2-Chloro-2-isobutyryl-1.3-cyclohexanedione
'H NMR (CDC13) : 6 1.09 (6H) d 7 H z ; 2.07 (2H) in; 2.7-3.0 (4H) m ; 3.18 (1H) m
7HZ.
13C NMR (CDC13) : 6 16.9 t corr. 6 2.07; 20.0 q corr. 6 1.09; 37.2 d corr. 6
3.18; 38.9 t c o n . 6 2.7-3.0; 89.2 s ; 195.9 s (2 x C-0); 203.2 s .
14
2-Chloro-S,S-dimethyl-2-propionyl-l,3-cyclohexanedione
'H NMR (CDC13) : 6 0.90 (3H) s * ' ; 1.03 (3H) t 7Hz; 1.18 (3H) s * ; 2.73 (2H) q
7Hz; 2.81 (4H) br. center of AB system.
13C NMR (CDC13) : 6 7.9 q corr. 6 1.03; 27.2 q corr. 6 0.90; 29.1 q corr. 6
1.18; 30.0 s ; 32.3 t corr. 6 2.73; 52.2 t corr. 6 2.81; 88.4 s ; 195.7 s (2 x
C=O); 199.6 s .
17
2-Chloro-5,5-dimethyl-2-~-butyryl-l,3-cyclohexanedione.
'H NMR (CDC13) : 6 0.89 (3H) t 7HZ; 0.89 (3H) s ; 1.19 (3H) s ; 1.60 (2H) m
7Hz; 2.70 (2H) t 7Hz; 2.84 (4H) br. center of A 9 system.
13C NMR (CDC13) : 6 13.2 q corr. 6 0.89; 17.1 t corr. 6 1.60; 27.1 q corr. 6
0.89; 29.2 q corr. 6 1.19; 30.0 s ; 40.3 t corr. 6 2.70; 52.4 t c o n . 6 2.84;
8 8 . 8 s ; 195.4 s (2 x C=O); 198.7 s .
20
2-Chloro-2-isobutyryl-5,5-dimethyl-l,3-cyclohexanedione
'H NMR (CDC13) : 6 0.88 (3H) s * * ; 1.10 (6H) d 7Hz; 1.20 (3H) s'; 2.83 (4H)
br. center of A9 system; 3.30 (1H) m 7Hz.
13C NMR (CDC13) : 6 19.8 q corr. 6 1.10; 27.0 q corr. 6 0 . 8 8 ; 29.2 q corr. 6
1.20; 30.0 s ; 37.0 d corr. 6 3.30; 52.5 t corr. 6 2.83; 89.3 s ; 195.4 s (2 x
C=O); 203.4 s .
Rearrangement in Hydrogen Chloride-Dimethylformamide
General Procedure : with protection against moisture the evaporated chlorinated
intermediate ( 0 . 2 mol) was immediately stirred with 200-240 ml of dimethylformamide containing 20-40 g dry hydrogen chloride. By rapid heating the temperature was raised to 120-130°C and maintained for 15-20 min. (Evolution of hydrogen chloride and carbon monoxide ! ) After sufficient cooling 70-801 of the
HC1-DMF was recovered by distillation in vacuo (b.p. 45-SS°C/ll mmHg; this
fraction can be used again). The residue was extracted with 5N aq. hydrochloric acid (300-400 ml) and diethylether (for resorcinols) or 1:l dichloromethane-carbon tetrachloride (for 2-acyl-4-chlorodimedones).
a) Resorcinols : The combined ether extracts (300
150 ml). washed with 100 ml
SN hydrochloric acid, dried (MgS04) and evaporated were distilled/sublimed
in vacuo, discarding a small liquid or semi-solid forerun. The main fraction, a yellow solid. was recrystallised from carbon tetrachloride-diethyl-
-
367
-
ether. Crystallisation was induced by gradually distilling off the ether
(pale yellow crystals). Direct crystallisation from 30-50% ethanol-water,
omitting the distillation, afforded slightly lower yields of brownish crystals, even if norit was used.
-1
-6
2-Acetylres~rcinol~
: m.p. 157OC sublim. 120-13O0C/O.01 mbar.
2-Propionylresorcinol : m.p. 136'C
sublim. 118-132°C/0.02 mbar.
I.R. (KBr) : 3280; 1634; 1585; 1509 (w); 1241; 1204 cm-l.
'H NMR (CDC13) : 6 1.20 (3H) t 7hz; 3.21 (2H) q 7Hz; 6.35 (1H) d 8.6Hz; 6.36
(1H) d 7.2Hz; 7.27 (1H) d d 8.6Hz 7.2Hz; 9.60 (2H) s.
13C NMR (CDC13 + 15% MeOH) : 6 8 . 5 q t 127.6Hz 4.OHz corr. 6 1.20; 38.1 t q
128.7Hz 4.2Hz corr. 6 3.21; 107.8 d d 163.6Hz 7.6Hz corr. 6 6.35 and 6.36;
110.3 br. t 5.3Hz; 136.1 d d 161.5Hz 1.8Hz corr. 6 7.27; 162.2 d t 10.4Hz 1.OHz;
209.6 m 5.OHz.
-9
2-Isobutyrylresorcinol : m.p. ll2OC (CH2C12-CC14); b.p. 105-110°C/0.02 mbar.
I.R. (KBr) : 3300; 1630; 1595; 1515; 1255; 1210 cm-l.
'H NMR (CDC13) : 6 1.22 (6H) d 7Hz; 4.06 (1H) m 7Hz; 6.45 (1H) d 8.4Hz; 6.46
(1H) d 7.2Hz; 7.27 (1H) d d 8.4Hz 7.2Hz; 10.45 (2H) br. s.
13C NMR (CDC13) : 6 19.1 q m 127.8Hz 4.9Hz corr. 6 1.22; 40.1 d m 133.9Hz
3.9Hz corr. 6 4.06; 108.6 d d d 163.3Hz 7.7Hz 4.2Hz corr. 6 6.45-6.46; 109.6
m 5.6Hz; 136.2 d t 162.2Hz 1.8Hz corr. 6 7.27; 161.3 d d 10.2tiz 4.2Hz; 213.5
m 4.5Hz.
b) 2-Acyl-4-chlorodimedones : The combined extracts (250 + 2 x 50 ml of 1:l
CH2C12-CC14) were washed (100 ml of 5N hydrochloric acid), dried (MgS04), 1
largely evaporated in vacuo and diluted with 100-150 ml of carbon tetrachloride to precipitate 2-chlorodimedone (crystals m . p . 162-164'C separated
over 1-2 days at !O°C; if not separatcd previously this material tended t o
co-distill at 85-llO"C/O.OZ mbar). The solution was concentrated and distilled in vacuo using a 30 cm Vigreux column. The main fraction was recrystallized at -3OOC from a small amount of hexane.
12
2-Acetyl-4-chloro-5,5-dimethyl-l,3-cyclohexanedione : m.p. 49OC; b.p.
140DC/14 mmHg o r 67-73OC/O.O4 mbar; pKa 5.6 (60% MeOH); U.V. (MeOH) Xmax :
241 and 278 mu. I.R. (KBr) : 1690; 1570 (v br.) cm-l.
'H NMR (CDC13) (9O:lO mixture of two chelated enol forms A and B; the major
form excludes the a-halogenated carbonyl group from hydrogen bonding).
A : 6 1.15 (6H) br. s ; 2.46 (1H) d d 18.OHz 1.OHz; 2.58 (3H) s ; 2.90 (1H) d*
18.OHz; 4.11 (1H) d 1Hz; 17.60 (1H) br. s. B (partial) : 2.62 (3H) s ; 4.38
(1H) d 1Hz; 17.37 (1H) br. s.
13C NMR (CDC13) : A : 6 24.7 q m 127.5Hz c o n . 6 1.15; 26.0 q m 128.5Hz corr.
6 1.15; 28.3 q d 129.7Hz 1.7Hz corr. 6 2.58; 34.8 s (m); 42.9 t br. m 129.5
Hz corr. 6 2.46-2.90; 69.7 d m 155.1Hz 4.7Hz corr. 6 4.11; 109.8 br. d 5.5Hz;
188.6 d 4.5Hz; 196.2 t d 6.9Hz 4.4Hz; 203.2 q d 6.2Hz 2.6Hz.
B (partial) : 6 24.8 q ; 26.3 q ; 27.3 q ; 35.1 s ; 48.3 t ; 66.6 d.
S i d e products : 2-Acetyl-4,6-dichloro-5,5-dimethyl-l~3-cyclohexanedione
(26):
b.p. 94-10O0C/O.03 mbar.
'H NMR (CDC13) : 6 1.27 (6H) s ; 2.66 (3H) s ; 4.31 (1H) h r . s ; 4.75 (1H) h r . s ;
17.60 (1H) br. s.
-
368
-
13C NMR (CDC13) : 6 22.6 q br. m 128Hz corr. 6 1.27; 22.7 q br. rn 128Hz
corr. 6 1.27; 27.3 q 130.5Hz corr. 6 2.66; 40.4 m 3.6Hz; 65.0 d br. m 153.2Hz
5.2Hz corr. 6 4.75; 68.4 d br. m 153.8Hz 4.7Hz c o n . 6 4.31; 108.9 s (br.);
186.6 d 4.7Hz; 192.1 d 5.4Hz; 202.6 q 6.2Hz.
2-Acetyl-4,S-dimethylresorcinol ( E ) : m.p. 130aC (CH2ClZ-CC14); b.p.
(sublirn.) 110-120°C/0.02 mbar. I . R . (KBr) : 3270; 1620 (br.); 1520 (w);
1149 cm-l.
'H NMR (CDC13 + 101 MeOH) : 6 2.02 (3H) s * ; 2.16 (3H) s * * ; 2.71 (3H) s ; 6.18
(1H) s * ; 8.95 (1H) v br. s ; 13.0 (1H) br. s.
13C NMR (CDC13
101 MeOH) : 6 10.5 q hr. s 127.OHz corr. 6 2.02; 2 0 . 8 q d
126.9Hz 5.3Hz corr. 6 2.16; 33.2 q 128.9Hz corr. 6 2.71; 108.1 d br. q 158.5Hz
4.9Hz corr. 6 6.18; 108.4 br. q 4.5Hz; 115.3 hr. m ; 146.9 br. m ; 158.0 s (br.);
161.4 m (5) 4.1Hz; 206.0 br. q 5.5Hz.
15 4-Chloro-5,5-dimethyl-2-propionyl-l,3-cyclohexanedione
: m.p. ZOOC; b.p.
82-86"C/0.02 mbar. I . R . (NaC1) : 1680; 1565 (hr.) cm-l.
'H NMR (CDC13) (92:8 mixture of forms A and B). A : 6 1.08 (3H) t 7Hz; 1.16
(3H) s * ; 1.19 (3H) s'; 2.57 (1H) d d 18.4Hz 1.OHz; 2.90 (1H) d 18.4Hz; 3.05
(2H) q 7Hz; 4.18 (1H) d 1.OHz; 17.66 (1H) br. s . B (partial) : 6 4.36 d 1.2Hz.
13C NMR (CDC13) ( A ) : 6 8.2 q t 128.1Hz 4.1Hz corr. 6 1.08; 24.4 q br. m
128Hz corr. 6 1.19; 33.9 t br. q 128.6Hr 3.9Hz corr. 6 3.05; 34.9 m 3.7Hz;
42.7 t br. m 129.5Hz corr. 6 2.57-2.90; 70.0 d m 155.OHz 4.7Hz corr. 6 4.18;
109.3 b r . d 5.3Hz; 188.3 d 4.5Hz; 195.5 t d 6.8Hz 4.4Hz; 206.9 m (6) d 5.5Hz
1.9Hz.
Side product : 4,6-Dichloro-5.5-dimethyl-?-propionyl-l,3-cyclohexanedione (27)
b.p. 14OoC/0.2 mbar.
'H NMR (CDC13) : 6 1.14 (3H) t 7Hz; 1.25 (6H) s; 3.11 (ZH) q 7Hz; 4.54 (1H) br.
s ; 4.79 (1H) br. s ; 17.8 (1H) br. s.
C
' NMR (CDC13) : 6 8 . 3 q corr. 6 1.14; 22.6 q corr. 6 1.25; 22.8 q corr. 6
1.25; 33.3 t corr 6 3.11; 40.5 s ; 64.9 d corr. 6 4.79; 68.5 d corr. 6 4.54;
108.4 s ; 186.7 s ; 191.5 s ; 206.8 s.
.-
18 4-Chloro-5,s-d r n e t h y l - 2 - ~ - b u t y r y l - l , 3 - ~ y c l o h e x a n e d i o n e: m.p.
ca. 20'C; b.p.
88-93*C/0.02 mbar
I.R. (NaCl) : 1678; 1550 ( v . br.) cm-l.
'H NMR (CDC13) (9 :9 mixture of forms A and B) : 6 0.96 (3H) t 6Hz; 1.15 (3H)
s * ; 1.19 (3H) s * ; 1.63 (ZH) m 6-7Hz; 2.52 (1H) d d 18.4Hz 0.8Hz; 2.89 (1H) d*
18.4Hz; 2.99 (2H) t 7Hz; 4.15 (1H) d 0.8Hz; 17.70 (1H) br. s . B (partial) :
4.45 d 0.8Hz.
13C NMR (CDC1,) : 6 13.8 q m l25Hz corr. 6 0.96; 18.0 t m 125Hz corr. 6 1.63;
24.4 q m 128Hz; 25.9 q m 128Hz; 34.8 m ; 42.0 t rn 125Hz corr. 6 2.99; 42.9 t m
130Hr corr. 6 2.52-2.89; 70.0 d m 154Hz 4.7Hz corr 6 4.15; 109.4 br. d 5.8Hz;
188.3 d 4.5Hz; 196.0 t d 7.OHz 4.2Hz; 206.0 m.
-
21 4-Chloro-Z-isobutyryl-5~5-dimethyl-l,3-cyclohexanedione
: m.p. 32'C; b.p.
80-84"C/0.02 mbar. I . R . (NaCl) : 1678; 1550 ( v . b r . ) cm-l.
'H NMR (CDCI3) (92:s mixture of forms A and B) : 6 1.12 (6H) d 6.5Hz; 1.17 (6H)
s ; 2.50 (1H) d d 18.2Hz 1.OHz; 2.91 (1H) d* 18.2Hz; 3.91 (1H) m 6.5Hz; 4.11
(1H) d 1.OHz; 17.9 (1H) s . B (partial) : 6 4.41 d 1.OHz.
-
369
-
1 3 C NMR (CDC13) : 6 18.5 q m 128Hz 4.5Hz c o n . 6 1.12; 18.6 q m l28Hz 4.5Hz
c o r r . 6 1.12; 24.5 q b r . m 128Hz; 25.8 q b r . m 128Hz; 34.6 m 3.7Hz; 36.0 d m
154.4Hz 4.OHz c o r r . 6 3.91; 42.8 t b r . m 130Hz c o n . 6 2.50-2.91; 70.0 d m 156
Hz 4.7Hz c o n . 6 4.11; 108.3 b r . d 4Hz; 1 8 8 . 3 d 4.5Hz; 196.3 b r . t 7Hz; 210.2
m 4.8Hz.
References
1. A . F r i e s z , G . Csermely C.A. 99 P 122306~.
2. A . R u s s e l , J.R. F r y e Org. Synth. 11 2 2 (1941).
3 . F i s o n s P h a r m a c e u t i c a l s C.A.
P 4 3 4 5 2 ~(1970) F r . 1.559.722 14-3-1969,
Brit: Appl. 22-12-1966.
4. A . F r i e s z , G . Csermely C.A. 99 P 122034d (1983). Hung. T e l j e s HU 24,590
2 8 - 3 - 1983.
5. A . F r i e s z . C . Csermely C . A . 2 P 158017q Hung. T e l j e s HU 24,587 28-3-1983
6. N. Schamp, R. Verhb, L. De Buyck T e t r a h e d r o n g 3857 (1973).
7. L. De Buyck, N. Schamp, R. Verhb T e t r a h e d r o n L e t t e r s 2491 (1975).
8 . A.A. Akhrem, F . A . L a k v i c h , S . I . B u d a i , T.S. Xhlebnikova, 1 . 1 . P e t r u s e v i c h
S y n t h e s i s 925 (1978).
9. G. Reissenweber, W. R i c h a r z (BASF A . G . ) Ger. O f f e n . DE 3,314,816
25-10-1984, C.A. 102 78433n (1985).
10. L. De Buyck, R. Verhb, N. De Kimpe, N. Schamp B u l l . SOC. Chin. B e l g . , 89
307 (1980).
1 1 . A l d r i c h D15,855-0; J a n s s e n Chimica 11-622.79.
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