Reaction of synthetic equivalents of arylideneimines, viz., 1-aryl- N,N'-bis(arylidene)methanediamines, with 2,3-diphenylcyclopropenone

Article abstract of DOI:10.1007/s11172-009-0023-5

N,N'-Bis(arylidene)methanediamines regiospecifically react with 2,3-diphenylcyclo- propenone to form stable adducts of both the mono- and the diaddition. Ammonium acetate serves as the catalyst of the process. During hydrolysis of these adducts, an oxidat

Full text of DOI:10.1007/s11172-009-0023-5

Russian Chemical Bulletin, International Edition, Vol. 58, No. 1, pp. 152—155, January, 2009
152
Reaction of synthetic equivalents of arylideneimines,
viz., 1ꢀarylꢀN,N´ꢀbis(arylidene)methanediamines,
with 2,3ꢀdiphenylcyclopropenone*
N. A. Lozinskaya, S. E. Sosonyuk, Yu. N. Firsova, M. V. Proskurnina, and N. S. Zefirov
M. V. Lomonosov Moscow State University, Department of Chemistry,
1 Leninskie Gory, 119992 Moscow, Russian Federation.
Fax: +7 (495)935 0290. Eꢀmail: natalylozinskaya@gmail.com
N,N´ꢀBis(arylidene)methanediamines regiospecifically react with 2,3ꢀdiphenylcycloꢀ
propenone to form stable adducts of both the monoꢀ and the diaddition. Ammonium acetate
serves as the catalyst of the process. During hydrolysis of these adducts, an oxidative coupling
of 1,2ꢀdihydroꢀ3Hꢀpyrrolꢀ3ꢀones occurs with the formation of 2,2´,4,4´,5,5´ꢀhexaarylꢀ1,1´,2,2´ꢀ
tetrahydroꢀ3H,3´Hꢀ2,2´ꢀbipyrroleꢀ3,3´ꢀdiones.
Key words: N,N´ꢀbis(arylidene)methanediamines, dihydropyrrolones, cyclopropenones,
oxidative coupling.
Nowadays, for the search of compounds possessing
we set a problem to study cycloaddition of these bisimines
biological activity similar to that of peptides, but having
improved pharmacodynamic properties, a directed design
and synthesis of peptidomimetics is utilized. The latter
include, in particular, 3,5ꢀlinked 1,2ꢀdihydropyrrolones
(A), the heterocyclic ring of which imitates the spatial
structure of a protein molecule in the form of βꢀfold (B).1
to cyclopropenones in order to subsequently synthesize
dihydropyrrolones and bisꢀ1,2ꢀdihydropyrrolones, potenꢀ
tial peptidomimetics.
Results and Discussion
It is known3 that 1ꢀarylꢀN,N´ꢀbis(arylidene)methaneꢀ
diamines, readily formed by the reaction of aromatic
aldehydes with ammonia, are used in the synthesis as
stable ArCH=NH synthons. We have found that the reaction
of 2,4ꢀdiazapentadienes 1 (Scheme 1) with 2,3ꢀdiphenylꢀ
Scheme 1
In the last years, a series of compounds with the key
polypyrrolone fragment, which are inhibitors of the HIVꢀ1
protease, have been found.2 Using these data and conꢀ
tinuing our studies on the synthesis of “twinꢀdrugs” (physiꢀ
ologically active compounds containing two pharmacoꢀ
phoric groups, covalently attached to one molecule) on
the basis of 1ꢀarylꢀN,N´ꢀbis(arylidene)methanediamines,3
1, 2: Ar = Ph (a); 4ꢀMeOC H (b), 4ꢀMeC H (c);
6
4
6 4
3: Ar = 4ꢀMeOC H
* Dedicated to Academician A. I. Konovalov on his 75th birthday.
6
4
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 152—155, January, 2009.
1066ꢀ5285/09/5801ꢀ0152 © 2009 Springer Science+Business Media, Inc.

Addition of arylidenes to cyclopropenone
Russ.Chem.Bull., Int.Ed., Vol. 58, No. 1, January, 2009
153
cyclopropenone proceeds regiospecifically with the forꢀ
mation of substituted pyrrolꢀ3ꢀones. This process can
be either stopped after the formation of monoaddition
products, 1,2ꢀdihydroꢀ3Hꢀpyrrolꢀ3ꢀones (2) or can be
driven to the addition of two cyclopropenone molecules
to form bis(dihydroꢀ3Hꢀpyrrolꢀ3ꢀones), as it was shown
on the example of compound 3 (see Scheme 1).
1680—1690 cm–1
1640—1655 cm–1
spectra of the compounds synthesized by us and authentic
compounds.
When the ratio of components is 1 : 1, the formation
of adducts 2 proceeds under mild conditions (methanol,
room temperature) and the easiness of isolation of the
product is secured by its precipitation. A plausible scheme
includes the formation of polar intermediates, that subꢀ
stantiates a necessity to use a polar protic solvent (Scheme 2).
The IR spectra of pyrrolꢀ2ꢀones4 contain the absorpꢀ
tion band for the amide carbonyl group at ∼1680 cm–1
.
Pyrrolꢀ3ꢀones are the amide vinylogs and due to the elonꢀ
gation of the chain of conjugation, the vibration frequency
of the carbonyl is somewhat reduced (∼1650 cm–1).5 In
the products 2a—c and 3 synthesized by us, the absorpꢀ
Scheme 2
tion band for the carbonyl group is at 1640—1670 cm–1
,
that additionally confirms their structure. Regioselectivity
of the reaction was also confirmed by the 13C NMR specꢀ
tral data: for example, for compound 2a, the chemical
shift for the carbonyl group is at 196.69 ppm, that strictly
corresponds to the keto, rather than the amide form.
The yields of compounds 2 increase in the presence of
electronꢀdonating substituents in the aryl fragment of the
bis(arylidene)methanediamines, that also agrees with
the suggestion on the reaction mechanism including
nucleophilic attack by the nitrogen atom of the imine.5 As
it was found during optimization of conditions, the reaction
accelerates in the presence of anhydrous ammonium acetate,
that is caused, apparently, by the protonation of the carboꢀ
nyl group of cyclopropenone. Nevertheless, the reaction
time should be long enough to reach the highest yields.
Earlier, it has been found that the reaction of diphenylꢀ
cyclopropenone with azines led to the product initially
identified as 1,2ꢀdihydroꢀ4,5ꢀdiphenylꢀ3Hꢀpyrrolꢀ3ꢀone.6
Later, however, a suggestion has been made on a possible
oxidative coupling of 1,2ꢀdihydroꢀ4,5ꢀdiphenylꢀ3Hꢀpyrrolꢀ
3ꢀones, obtained by this reaction, under the action of air
oxygen.7 We studied the hydrolysis of adducts 2 and 3
obtained and found that the hydrolysis products are
dimers 4 (Scheme 4) earlier described6 as 4,5ꢀdiphenylꢀ
Compound 3 can also be obtained by the stepꢀwise
synthesis, involving into the reaction monoadduct 2b
and the second mole of diphenylcyclopropenone in
CHCl3—MeOH (Scheme 3).
Scheme 3
Scheme 4
Ar = 4ꢀMeOC H
6
4
It should be emphasized that the reaction of cycloꢀ
propenones with imines proceeds regioselectively with the
formation of the pyrrolꢀ3ꢀones, rather than pyrrolꢀ2ꢀones.
This fact was confirmed, in particular, by comparison of
the absorption bands of the carbonyl groups in the IR
4 Ar = Ph (a); 4ꢀMeOC H (b), 4ꢀMeC H (c)
6
4
6 4

154
Russ.Chem.Bull., Int.Ed., Vol. 58, No. 1, January, 2009
Lozinskaya et al.
Method A. A solution of 2,3ꢀdiphenylcyclopropenone and
1ꢀarylꢀN,N´ꢀbisꢀ(arylidene)methanediamine in anhydrous MeOH
was stirred at room temperature. A precipitate formed was filtered
off and washed with diethyl ether. For analysis, the sample was
recrystallized from ethanol or xylene.
1,2ꢀdihydroꢀ3Hꢀpyrrolꢀ3ꢀones, the reaction products of
diphenylcyclopropenone with azines.
A conclusion on the structures of compounds 4
obtained has been made on the basis of the 1H NMR and
MALDI spectral data for compound 4b. In the 1H NMR
spectra, the signal for the proton at the carbon atom C(2)
of the pyrrole ring is absent. The presence of peaks 703
(M++ Na), 680 (M+), and 679 (M+ – H) in the MALDI
spectra suggests the structure 4; on ionization of this
compound by the electron impact method, the molecular
ion peak is absent in the mass spectrum, however, the
presence, along with the peak m/z 341 (C23H19NO2)
belonging to the molecule of monomer, of intensive peak
M – 2H (C23H17NO2), which can result from the McLafferty
cleavage, also suggests the oxidative coupling (Scheme 5).
Method B. A solution of 2,3ꢀdiphenylcyclopropenone, 1ꢀarylꢀ
N,N´ꢀbisꢀ(arylidene)methanediamine and dry ammonium acetate
in anhydrous MeOH were stirred at room temperature. The
precipitate was filtered off and washed with diethyl ether.
Nꢀ(Benzylideneamino)(phenyl)methylꢀ2,4,5ꢀtriphenylꢀ
1,2ꢀdihydroꢀ3Hꢀpyrrolꢀ3ꢀone (2a). A. Compound 2a (1.20 g, 64%)
was obtained by the reaction of 2,3ꢀdiphenylcyclopropenone
(0.760 g, 3.7 mmol) and compound 1a (1.10 g, 3.7 mmol) in
MeOH (20 mL) for 3 h. M.p. 275—279 °C (decomp., EtOH).
Found (%): C, 85.45; H, 5.40; N, 5.67. C36H28N2O. Calculated
1
(%): C, 85.69; H, 5.59; N, 5.55. H NMR (CDCl3), δ: 5.29 (s,
1 H, N—CH—N=); 6.50 (s, 1 H, N—CH—C=O); 6.90 (d, 2 H,
HAr, J = 7.1 Hz); 7.06—7.14 (m, 4 H, HAr); 7.23—7.27 (m, 5 H,
HAr); 7.33—7.39 (m, 8 H, HAr); 7.57—7.62 (m, 4 H, HAr); 7.92
(d, 2 H, HAr, J = 7.3 Hz); 8.00 (s, 1 H, CH=N). 13C NMR
(CDCl3), δ: 75.70, 80.93 (O=CCHN); 125.42, 127.04, 127.47,
127.90, 124.34, 128.34, 128.68, 128.77 (O=C—C=); 131.20,
131.74, 136.42, 139.00 (Ph), 162.56 (=NCHNH); 173.02
(CH=N); 196.69 (C=O). IR, ν/cm–1: 1580, 1610, 1640 (C=O).
B. Compound 2a (269 mg, 53%) was obtained by the reaction
of 2,3ꢀdiphenylcyclopropenone (206 mg, 1.0 mmol), compound
1a (300 mg, 1.0 mmol), and dry NH4OAc (100 mg, 1.3 mmol) in
anhydrous MeOH (4 mL) for 3 h.
Scheme 5
Nꢀ(4ꢀMethoxybenzylideneamino)(phenyl)methylꢀ2ꢀ(4ꢀmethoxyꢀ
phenyl)ꢀ4,5ꢀdiphenylꢀ1,2ꢀdihydroꢀ3Hꢀpyrrolꢀ3ꢀone (2b). A. Comꢀ
pound 2b (515 mg, 87%) was obtained by the reaction of 2,3ꢀdiꢀ
phenylcyclopropenone (206 mg, 1.0 mmol) and compound 1b
(389 mg, 1.0 mmol) in MeOH (4 mL) for 2 days. M.p. 235—241 °C
(decomp., EtOH). Found (%): C, 78.64; H, 5.84; N, 4.82.
C39H34N2O4. Calculated (%): C, 78.77; H, 5.76; N, 4.71.
1H NMR (CDCl3), δ,: 3.74 (s, 3 H, OCH3); 3.76 (s, 3 H,
OCH3); 3.82 (s, 3 H, OCH3); 5.14 (s, 1 H, N—CH—N=); 6.45
(s, 1 H, N—CH—C=O); 6.76 (d, 2 H, HAr, J = 8.3 Hz); 6.86
Ar = 4ꢀCH OC H
6 4
3
Compounds 3 under hydrolysis conditions for comꢀ
pounds 2 are converted to compounds 4 in high yields.
Their formation can be explained by the oxidation under
the action of air oxygen: the intermediate A oxidizes to
3Hꢀpyrrolꢀ3ꢀone, which the second molecule of the
intermediate A is added to (see Scheme 4).
(m, 4 H, HAr); 6.92 (d, 2 H, HAr); 6.99—7.15 (m, 4 H, HAr
,
J = 7.1 Hz); 7.37 (t, 2 H, HAr, J = 7.6 Hz); 7.45—7.50 (m, 4 H,
HAr); 7.54 (d, 2 H, HAr, J = 8.6 Hz); 7.80 (d, 2 H, HAr, J = 8.6 Hz),
7.91 (s, 1 H, CH=N). IR, ν/cm–1: 1560, 1580, 1610, 1670
(C=O). UV (DMF): λmax 363 nm.
B. Compound 2b (544 mg, 92%) was obtained by the reaction
of 2,3ꢀdiphenylcyclopropenone (231 mg, 1.1 mmol), compound
1b (436 mg, 1.1 mmol), and anhydrous NH4OAc (130 mg,
1.7 mmol) in MeOH (4 mL) for 24 h.
Experimental
1H NMR spectra were recorded on a Bruker Avanceꢀ400
spectrometer (400.13 MHz (1H) and 100.61 MHz (13C)). IR
spectra were recorded on a Carl Zeiss URꢀ20 spectrophotometer
in Nujol. Elemental analysis was carried out on a Carlo Erba
automatic analyzer. Melting points were measured with an
Electrothermal 9100 melting point indicator in a sealed capillary
tube. Mass spectrometric analyses were performed on a Finnigan
MATINCOSSO (70 eV, direct injection) and Bruker Datonics
auTOFex (MALDIꢀTOF) mass spectrometers. UV spectra were
recorded on a Helios γ ThermoNicolet spectrophotometer.
The starting 1ꢀarylꢀN,N´ꢀbis(arylidene)methanediamines were
obtained according to the procedure described earlier.8
Nꢀ(4ꢀMethylbenzylideneamino)(phenyl)methylꢀ2ꢀ(4ꢀmethylꢀ
phenyl)ꢀ4,5ꢀdiphenylꢀ1,2ꢀdihydroꢀ3Hꢀpyrrolꢀ3ꢀone (2c). A. Comꢀ
pound 2c (1.58 g, 88%) was obtained by the reaction of 2,3ꢀdiꢀ
phenylcyclopropenone (0.75 g, 3.6 mmol) and compound 1c
(1.13 g, 3.3 mmol) in MeOH (4 mL) for 2 days. Pale yellow
crystals. M.p. 241—245 °C (decomp., xylene). Found (%):
C, 85.69; H, 6.38; N, 5.02. C39H34N2O. Calculated (%): C, 85.68;
H, 6.27; N, 5.12. 1H NMR (CDCl3), δ: 2.27 (s, 3 H, CH3); 2.28
(s, 3 H, CH3); 2.35 (s, 3 H, CH3); 5.21 (s, 1 H, N—CH—N=);
6.56 (s, 1 H, N—CH—C=O); 6.90 (d, 2 H, HAr, J = 7.4 Hz);
7.01—7.49 (m, 4 H, HAr); 7.75 (d, 2 H, HAr, J = 7.8 Hz); 7.97 (s,
1 H, CH=N). IR, ν/cm–1: 1605, 1640, 1660 (C=O).
Compounds 2a—c, 3 and 4a—c were synthesized according
to the described methods based on the reaction of 2,3ꢀdiphenylꢀ
cyclopropenone with 1ꢀarylꢀN,N´ꢀbis(arylidene)methanediamines.
B. Compound 2c (544 mg, 92%) was obtained by the reaction
of 2,3ꢀdiphenylcyclopropenone (215 mg, 1.04 mmol), compound

Addition of arylidenes to cyclopropenone
Russ.Chem.Bull., Int.Ed., Vol. 58, No. 1, January, 2009
155
1c (335 mg, 1.04 mmol), and anhydrous NH4OAc (154 mg,
2.0 mmol) in MeOH (4 mL) for 5 h.
[M+ + Na], calculated: M = 703.779; found: m/z 680.202 [M+],
calculated: M = 680.789; found: m/z 679.171 [M+ – H],
calculated: M = 679.781. MS MALDIꢀTOF (anthracene
was the matrix), found: m/z 703.226 [M+ + Na], calculated:
M = 703.779; found: m/z 680.307 [M]+, calculated: M = 680.789;
found: m/z 679.302 [M+ – H], calculated: M = 679.781.
Compound 4b (95 mg, 96%) was also obtained by the
hydrolysis of compound 3b (116 mg, 0.145 mmol) in conc.
hydrochloric acid (25 mL) for 26 h at 80 °C.
2,2´ꢀBis(4ꢀmethylphenyl)ꢀ4,4´,5,5´ꢀtetraphenylꢀ1,1´,2,2´ꢀ
tetrahydroꢀ3H,3´Hꢀ2,2´ꢀbipyrrolꢀ3,3´ꢀdione (4c). A suspension
of compound 2b (318 mg, 0.582 mmol) in conc. hydrochloric
acid (10 mL) was kept for 2 h at 70—80 °C. Compound 4c
(114 mg, 62%), light yellow crystals, m.p. 260—262 °C (decomp.,
xylene; cf. Ref. 6: 269—271 °C (benzene)). 1H NMR (400.13 MHz,
CDCl3), δ: 2.28 (s, 6 H, CH3), 6.90 (d, 4 H, HAr, J = 7.1 Hz),
7.05 (d, 4 H, HAr, J = 7.8 Hz), 7.10—7.20 (m, 10 H, HAr), 7.32
(t, 4 H, HAr, J = 7.7 Hz), 7.45 (t, 2 H, HAr, J = 7.3 Hz), 7.87 (d,
4 H, HAr, J = 8.3 Hz), 7.91 (s, 2 H, NH).
1,1´ꢀ[(4ꢀMethoxyphenyl)methylene]bis[2ꢀ(4ꢀmethoxyphenyl)ꢀ
4,5ꢀdiphenylꢀ1,2ꢀdihydroꢀ3Hꢀpyrrolꢀ3ꢀone] (3). A. A solution of
2,3ꢀdiphenylcyclopropenone (165 mg, 0.8 mmol) and compound
1b (142 mg, 0.37 mmol) in CHCl3—MeOH (5 : 3, 16 mL) was
stirred at room temperature for 9 days. The light yellow crystals
of 2c were filtered off and washed with diethyl ether. The yield
was 118 mg (40%). M.p. 279—283 °C (decomp., xylene). Found
(%): C, 80.81; H, 5.40; N, 3.61; C54H44N2O5. Calculated (%):
C, 80.98; H, 5.54; N, 3.50. 1H NMR (400.13 MHz, DMSOꢀd6—
CDCl3), δ: 3.66 (s, 6 H, OCH3); 3.72 (s, 3 H, OCH3); 6.70 (d,
4 H, HAr, J = 8.9 Hz); 6.73 (d, 4 H, HAr, J = 8.3 Hz); 6.78 (s,
1 H, N—CH—N); 6.82 (d, 2 H, HAr, J = 8.6 Hz); 6.96—7.04
(m, 6 H, HAr); 7.17 (d, 4 H, HAr, J = 7.3 Hz); 7.28—7.35 (m,
6 H, HAr); 7.52 (d, 2 H, HAr, J = 8.6 Hz), 7.90 (d, 4 H, HAr
,
J = 8.9 Hz) 8.92 (s, 2 H, N—CH—C=O). IR, ν/cm–1: 1580,
1610, 1640 (C=O), 3150—3300 (bonded OH).
B. A solution of compound 2b (217 mg, 0.36 mmol) and
2,3ꢀdiphenylcyclopropenone (83 mg, 0.40 mmol) in CHCl3—
MeOH (11 : 7, 18 mL) was stirred at room temperature for
9 days. The pale yellow crystals of 3a formed were filtered off and
washed with diethyl ether to obtain compound 3 (100 mg, 34%).
Products 4a—c were obtained by hydrolysis of compounds
2 and 3. A suspension of compound 2 or 3 in concentrated
hydrochloric acid was heated in a water bath (70—80 °C) for
2—29 h. The product was extracted with CHCl3, dried with
anhydrous sodium sulfate, the solvent was evaporated in vacuo,
and the residue was washed on the filter with diethyl ether.
2,2´,4,4´,5,5´ꢀHexaphenylꢀ1,1´,2,2´ꢀtetrahydroꢀ3H,3´Hꢀ
2,2´ꢀbipyrroleꢀ3,3´ꢀdione (4a). A suspension of compound 2a
(300 mg, 0.594 mmol) in conc. hydrochloric acid (17 mL) was
kept at 75—80 °C for 29 h. Compound 4a (114 mg, 62%), light
yellow crystals, m.p. 275—277 °C (decomp., xylene; cf. Ref. 6:
279—284 °C (DMF)).
2,2´ꢀBis(4ꢀmethoxyphenyl)ꢀ4,4´,5,5´ꢀtetraphenylꢀ1,1´,2,2´ꢀ
tetrahydroꢀ3H,3´Hꢀ2,2´ꢀbipyrroleꢀ3,3´ꢀdione (4b). A suspension
of compound 2b (200 mg, 0.336 mmol) in conc. hydrochloric
acid (20 mL) was kept at 70—80 °C for 19 h. Compound 4b
(63 mg, 55%), light yellow crystals, m.p. 278—281 °C (decomp.,
xylene; cf. Ref. 6: 282—285 °C (benzene)). 1H NMR (400.13 MHz,
CDCl3), δ: 3.73 (s, 6 H, CH3); 6.77 (d, 4 H, HAr, J = 8.8 Hz);
6.91 (d, 4 H, HAr, J = 7.3 Hz); 7.10—7.18 (m, 6 H, HAr); 7.21
(d, 4 H, HAr, J = 7.6 Hz); 7.32 (t, 4 H, HAr, J = 7.3 Hz); 7.45 (t,
2 H, HAr, J = 7.3 Hz); 7.91 (d, 4 H, HAr, J = 8.8 Hz); 7.96 (s,
2 H, NH). 13C NMR (100.61 MHz, CDCl3), δ: 55.31 (CH3);
72.51 (O=C—C—NH); 112.88, 124.88 (O=C—C=); 126.04,
127.91, 128.08, 128.56, 128.85, 131.26 (=C—NH); 159.62
(CAr—OMe); 172.23, 198.34 (C=O). IR, ν/cm–1: 1520, 1545,
1580, 1610, 1640 (C=O); 3150—3380 (bonded OH). MS (EI,
70 eV), m/z (Irel (%)): 341 [C23H19NO2] (51), 339 [C23H17NO2]
(23), 326 [C22H16NO2] (17), 178 [PhC≡CPh] (100), 77 [Ph]
(5). MS MADLYꢀTOF (matrixꢀfree), found: m/z 703.079
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in revised form October 9, 2008