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Firstova et al.
respectively). 1H—1H NOESY experiments were carried out
with a Bruker DRXꢀ300 instrument. All NMR spectra were
recorded in DMSOꢀd6, the chemical shifts are given in the
δ scale and referenced to Me4Si (an internal standard).
IR spectra were run on a Perkin Elmer Spektrum RXꢀ1
spectrophotometer in Nujol mulls applied to KBr crystal plate.
For (4ꢀcarboxyphenyl)cycloalkanedicarboxylic acids 4a,b, IR
spectra were also measured in KBr pellets.
High resolution electrospray ionization (ESI) mass spectroꢀ
metry was performed on a Bruker micrOTOF II instrument.
Following commercially available reagents (pure and chemꢀ
ically pure) produced in Russia were used: maleic anhydride,
divinyl, cyclopentadiene. Aluminum chloride was purchased
from SigmaꢀAldrich. Solvents were dried and distilled prior to
use by the known procedures.11
acids 3a,b were synthesized in 80—90% yields by the modꢀ
ified procedure published earlier9 (see Experimental).
Earlier, in communication10 we have described synꢀ
thesis of compounds 4a,b by Friedel—Crafts electrophilic
aromatic substitution (AlCl3ꢀcatalyzed acylation with
acetyl chloride in tetrachloroethane). Tetrachloroethane
is a common solvent for these reactions; however, in the
present work transformation 3a,b → 4a,b was performed
in chloroform, which significantly facilitated the isolaꢀ
tion of the target products. When the reaction was carried
out in tetrachloroethane, the product yields do not exceed
40%, but in chloroform compounds 4a,b were obtained in
70—75% yields. Tricarboxylic acids 5a,b were syntheꢀ
sized by oxidation of the acetyl group of compounds 4a,b
preliminary converted into the corresponding sodium
salts. Oxidation was enabled using freshly prepared aqueꢀ
ous solution of sodium hypobromite. Compounds 5a,b
were obtained in ~60% yields.
For compounds 3a,b, physicochemical properties absent in
publication8 are given.
(1R*,2S*,4S*)ꢀ4ꢀPhenylcyclohexaneꢀ1,2ꢀdicarboxylic acid
(3a). Yield 82%, m.p. 170—173 °C. IR, ν/cm–1: 2520, 930 (OH);
1695 (C=O, acid); 1255 (C—O—C); 700 (Ar). 1H NMR
(DMSOꢀd6), δ: 1.47 (m, 1 H, Hf); 1.77 (m, 2 H, Hb, Hb’); 1.95
(m, 1 H, He´); 2.21 (m, 1 H, Hb´); 2.45 (m, 2 H, He); 2.58 (m, 1 H,
Hd); 3.18 (m, 1 H, Hc); 3.37 (m, 1 H, Ha); 7.17 (d, 2 H, Ar,
J = 7.5 Hz); 7.25 (t, 3 H, Ar, J = 14.8 Hz); 12.02 (s, 2 H, COOH).
(1R*,2R*,3S*,4S*,5S*)ꢀ5ꢀPhenylbicyclo[2.2.1]heptaneꢀ
2,3ꢀdicarboxylic acid (3b). Yield 90%, m.p. 175—178 °C. IR,
ν/cm–1: 2530, 930 (OH); 1690 (C=O, acid), 1240 (C—O—C);
740, 710 (Ar). 1H NMR (DMSOꢀd6), δ: 1.37 (m, 1 H, Hg´);
1.56 (m, 2 H, Hf´, Hg); 2.01 (m, 1 H, Hf); 2.44 (m, 1 H, Hb);
2.60 (m, 1 H, He); 2.90 (m, 1 H, Hd); 3.06 (m, 1 H, Hc); 3.48
(m, 1 H, Ha); 7.17 (d, 2 H, Ar, J = 7.0 Hz); 7.25 (d, 3 H, Ar,
J = 7.0 Hz), 11.87 (s, 2 H, COOH).
Structures of the synthesized compounds were conꢀ
firmed by IR and NMR spectroscopy and high resolution
electrospray ionization mass spectrometry.
Synthesis of (4ꢀacetylphenyl)cycloalkanedicarboxylic acids
4a,b (general procedure). Dicarboxylic acid 2a,b (0.1 mol) was
dissolved in chloroform (15 mL) in a threeꢀneck flask fitted
with reflux condenser and thermometer. Then aluminum chlorꢀ
ide (0.4 mol) was added by portions followed by addition of
acetyl chloride (0.1 mol). The reaction mixture was heated at
60 °C for 5 h. After the reaction completion, the mixture was
poured into iceꢀwater (100 mL) and the product was precipitated
by adding 36% HCl (5 mL). The product was collected by filꢀ
tration, recrystallized from aqueous acetic acid, washed with
water, and dried at 50 °C.
(1R*,2S*,4S*)ꢀ4ꢀ(4ꢀAcetylphenyl)cyclohexaneꢀ1,2ꢀdicarꢀ
boxylic acid (4a). Yield 75%, m.p. 173—176 °C. IR, ν/cm–1
:
Presence of wellꢀresolved cross peaks in 1H—1H NOESY
spectra of compounds 5a,b indicates the couplings beꢀ
tween the aryl and alicyclic protons. This in turn is indicative
of the equatorial positions of the carboxyphenyl substituꢀ
ents in these compounds. The couplings of the alicyclic
protons confirmed that two carboxyl groups are synꢀaxial.
In summary, we elaborated simple and versatile proꢀ
cedure to access new aryl alicyclic tricarboxylic acids,
promising monomers for the synthesis of poly(amidoꢀ
imide)s and other heterocyclic polymers.
2728, 2678, 2643, 934 (OH); 1713 (C=O, acid); 1698,
1255 (C=O, ketone); 1600 (Ar); 1291 (C—O—C). 1H NMR
(DMSOꢀd6), δ: 1.54 (m, 1 H, Hf); 1.62 (m, 2 H, Hb, Hf´); 1.86
(m, 1 H, He´); 1.96 (m, 1 H, Hb); 2.17 (m, 1 H, He); 2.54 (m, 3 H,
CH3C(O)); 2.57 (m, 1 H, Hc); 3.19 (m, 1 H, Ha); 7.35 (d, 2 H,
Ar, J = 8.1 Hz); 7.88 (d, 2 H, Ar, J = 8.4 Hz); 12.00 (s, 2 H,
COOH). MS (ESI), m/z: found 291.1227 [M + H]+. Calculatꢀ
ed for C16H19O5: 291.1233.
(1R*,2R*,3S*,4S*,5S*)ꢀ5ꢀ(4ꢀAcetylphenyl)bicyclo[2.2.1]ꢀ
heptaneꢀ2,3ꢀdicarboxylic acid (4b). Yield 70%, m.p. 127—130 °C.
IR, ν/cm–1: 2746, 2651, 2557, 930 (OH); 1703 (C=O, acid);
1688, 1240 (C=O, ketone); 1602 (Ar); 1309 (C—O—C).
1H NMR (DMSOꢀd6), δ: 1.37 (m, 1 H, Hg´); 1.56 (m, 2 H,
Hf´, Hg); 2.07 (m, 1 H, Hf); 2.41 (m, 2 H, Hb); 2.51 (m, 3 H,
CH3C(O)); 2,61 (m, 1 H, He); 2.91 (m, 1 H, Hd); 3.02 (m, 1 H,
Hc); 3.47 (m, 1 H, Ha); 7.16 (d, 2 H, Ar, J = 8.1 Hz); 7.30
(d, 2 H, Ar, J = 8.4 Hz; 12.00 (s, 2 H, COOH). MS (ESI),
Experimental
1H and 13C NMR spectra were recorded with a Bruker
DRXꢀ500 instrument (working frequencies of 500 and 125 MHz,