Transformations of stereoisomeric 2-chloro-3-R-pentane-1,5-diones in reaction with phenylhydrazine

Article abstract of DOI:10.1134/S1070428007020108

Monophenylhydrazones were prepared from three monochloro derivatives of arylaliphatic 1,5-diketones, and some their transformations were investigated. The monophenylhydrazones formed regiospecifically, and the direction of the reaction was governed by the

Full text of DOI:10.1134/S1070428007020108

ISSN 1070-4280, Russian Journal of Organic Chemistry, 2007, Vol. 43, No. 2, pp. 214−219. © Pleiades Publishing, Ltd. 2007.
Original Russian Text © T.V. Moskovkina, A.I. Kalinovskii, 2007, published in Zhurnal Organicheskoi Khimii, 2007, Vol. 43, No. 2, pp. 222−227.
Transformations of Stereoisomeric
2-Chloro-3-R-pentane-1,5-diones in Reaction with Phenylhydrazine
T. V. Moskovkinaa andA. I. Kalinovskiib
aFar-Eastern State University, Vladivostok, 690600 Russia
e-mail: stonik@piboc.dvo.ru
bPacific Institute of Bioorganic Chemistry, Far-Eastern Division, Russian Academy of Sciences, Vladivostok, Russia
Received February 10, 2006
Abstract—Monophenylhydrazones were prepared from three monochloro derivatives of arylaliphatic 1,5-diketones,
and some their transformations were investigated. The monophenylhydrazones formed regiospecifically, and the
direction of the reaction was governed by the substituent attached to C3 atom in the initial chlorodiketones.
Formerly unknown products of transformations suffered by monophenylhydrazones obtained were described:
2-amino-1,3-diphenyl-3-(2-phenylindolyl-3)-propan-1-one, 3-benzoyl-2,4,6-triphenyl-2,3,4,5-tetrahydropyridazine,
and 3-methyl-1,5-diphenyl-5-phenylazopent-4-en-1-one.
DOI: 10.1134/S1070428007020108
Monochloro derivatives of 1,5-diketone are promising
available synthons for preparation of versatile carbocyclic
and heterocyclic compounds including also physiologically
active substances. These derivatives can be prepared
from various 1,5-diketones either by treating with chlorine
[1] or with the reagents of tervalent iodine: phenylchloro-
iodonium chloride (C6H5ICl2) and benzyltrimethyl-
ammoniumdichloroiodide (BTMAICl2) [2].
IVb by reactions of diketones I and II respectively with
BTMAICl2 in CH3COOH [2]. Stereoisomeric chloro-
ketone IVa we previously obtained in a low yield [2],
and it was not used in further study. Compounds IIIa
and IIIb are stereoisomers containing in the molecule
two asymmetric atoms C2 and C3.
The reaction of γ-haloketones with arylhydrazines in
a neutral medium (heating in methanol or ethanol) is
known to have resulted formerly in tryptamine derivatives
[3].As follows from the presumed scheme of the reaction
[4] the formation of tryptamines from the corresponding
2-chloro-1,5-pentanediones IIIa, IIIb, and IVb inevitably
requires in the first stage phenylhydrazones formation at
the carbonyl group not linked to the CHCl fragment of
the molecule. This condition was actually fulfilled for
stereoisomeric monochlorodiketones IIIa and IIIb. We
obtained from these compounds phenylhydrazones Va and
Vb respectively. Their monophenylhydrazone structure
was confirmed by IR and mass spectra. The IR spectra
Still we believe that the reactivity of both carbonyl
groups in these compounds and the range of
transformations of monochloro derivatives of arylaliphatic
1,5-diketones are quite insufficiently understood. The aim
of this study was investigating reactions of monochloro
derivatives of two diketones, 1,3,5-triphenyl-1,5-pentane-
dione (I) and 3-methyl-1,5-diphenyl-1,5-pentanedione (II),
with phenylhydrazine and subsequent transformations of
the corresponding monophenylhydrazones. We obtained
monochloro derivative IIIa by treating diketone I with
BTMAICl2 in DMF, and monochloro derivatives IIIb and
R
R
R
BTMAICl2
CH3COOH
Cl
Cl
BTMAICl2
DMF
3
4
5
2
1
C6H5
C6H5
C6H5
C6H5
C6H5
C6H5
O O
O O
O O
I, II
IIIb, IVb
IIIa
R = C6H5 (I, IIIa, IIIb), CH3 (II, IVa, IVb).
214

TRANSFORMATIONS OF STEREOISOMERIC 2-CHLORO-3-R-PENTANE-1,5-DIONES
215
C6H5
C6H5
C6H5
Cl
Cl
Cl
C6H5NHNH2
CH3COOH
C6H5NHNH2
CH3COOH
3
2
1
4
5
C6H5
C6H5
C6H5
C6H5
C6H5
C6H5
O O
N O
N O
NHC6H5
NHC6H5
IIIa, IIIb
Vb
Va
mp 158_159оС
mp 151_152оС
_ HМВC
contain absorption bands at 1682 (C=O), 1602 (C=N),
and 3315 (NH) cm–1. In the mass spectra of phenyl-
hydrazones Va and Vb (electrospray ionization) peaks of
pseudomolecular ions appeared at m/z 453 [M + H]+.
CHCl (5.58 ppm)/C=O (193.8 ppm) and CH–C6H5
(3.86 ppm)/C=O (193.8 ppm). Similarly, in HMBC
spectrum of compound Vb were found cross-peaks CHCl
(5.54 ppm)/C=O (194.1 ppm) and CH–C6H5 (3.96 ppm)/
C=O (194.1 ppm).
The assignment of signals in the NMR spectra of
compounds synthesized was performed using two-
dimensional homo- (COSY) and heteronuclear (HSQC,
HMBC) spectroscopy thus permitting unambiguous proof
of their structure and identification of the position of the
hydrazone fragment at the C5 atom in compounds Va
These data unambiguously indicate that the carbonyl
group adjacent to CHCl in both phenylhydrazones
remains free, and consequently the reaction with
phenylhydrazine occurs regiospecifically at a carbonyl
far from the CHCl group.
1
and Vb. For instance, the comparison of H and
At heating the stereoisomeric hydrazones Va and Vb
in ethanol we obtained the same tryptamine derivative
VI. This is not in contrast to the presumed scheme [4] of
such compounds formation given above in keeping with
transformations of compounds Va and Vb. It follows from
the scheme that the reaction involves the CHCl site which
undergoes chlorine elimination leading to the loss of the
asymmetry distinguishing the initial stereoisomers.
13C NMR spectra of compounds IIIa and IIIb and Va
and Vb shows that the CHCl group was conserved in
the reaction, and one of the carbonyls transformed into
1
phenylhydrazone. In the H NMR spectra of phenyl-
hydrazones Va and Vb signals of CHCl group were
observed as doublets which only for hydrazone Vb
suffered a slight upfield shift compared with the spectrum
of the initial chlorodiketone. The coupling constants H2−
H3 considerably changed in going from the spectrum of
chlorodiketone IIIb to that of phenylhydrazone Vb
indicating significant conformational transformations
apparently due to introduction into the molecule Vb of
a bulky phenylhydrazone moiety. The phenylhydrazone
character of compounds Va and Vb was also confirmed
by appearance in their 1H NMR spectra of signals from
NH group (8.5 and 8.92 ppm) and also of additional
signals from aromatic protons, and in the 13C NMR
spectra, of signals belonging to C=N group at 145.4 and
139.0 ppm respectively, and signals of C=O at 193.8
and 194.1 ppm.
The structure of tryptamine VI was confirmed by IR,
mass, and NMR spectra, and also by elemental analysis.
In the IR spectrum of the compound appeared absorption
bands at 1680 (C=O), 3460 (NH of indole ring), 3308,
and 3372 (NH2) cm–1, and in the mass spectrum, a peak
1
of a pseudomolecular ion [M + H]+ at m/z 417. H and
13C NMR spectra prove the presence of an indole
fragment in compound VI. 1H NMR spectrum contains
a singlet signal of NH group at 8.21 ppm, and 13C NMR
spectrum, doublet signals at 111.3, 120.3, 121.0, and
122.3 ppm, and also singlets at 111.2, 129.7, 136.4, 137.8,
ppm, characteristic of doubly substituted indole ring.
Assignment of signals was carried out by comparison
with calculated values and with the use of COSY-45,
HSQC, and HMBC experiments. Thus COSY-45
spectrum revealed the nonaromatic CH–CH fragment
and the four-proton system of the benzene ring of indole
and there three-proton systems of phenyl substituents.
The key HMBC correlations, in particular, C2H (5.5 ppm,
d)/C3 (48.4 ppm, d), CO (202.1 ppm, s), and also C3H
The position of the hydrazone moiety in compounds
Va and Vb was successfully established by 2D NMR
experiments. For instance, COSY spectra revealed the
presence in these compounds of a spin system CH–CH–
CH2, and HSQC experiment revealed a correlation
between 1H and 13C NMR spectra. In HMBC spectrum
of phenylhydrazone Va cross-peaks were observed for
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MOSKOVKINA, KALINOVSKII
216
Scheme.
Cl _
C6H5
C H
6 5
HCl
N
C6H5
C6H5
COC6H5
C6H5
HN
+
NH N
NH N
C6H5
C6H5
O
O
Cl
Va, Vb
C6H5
C6H5
C6H5
C6H5
COC6H5
COC6H5
NH
[3,3]
N HCl
N HCl
HCl
COC6H5
C6H5
NH
NH
N
H
2 C6H5
C6H5
1
3
H
H
H
CO
CO
4
2
H
NH2
3
H
H
1
N
N
N
C6H5
H
VI
VII
_ Key НМВС correlations
(4.87 ppm, d)/C2 (58.2 ppm, d), CO (202.1 ppm, s) are
given on the scheme.
carbonyl was proved by HMBC and HSQC experiments,
in particular, by cross-peaks C3H (5.71 ppm, t)/CO
(196.5 ppm, s) and C4H (3.82 ppm, d.t)/CO (196.5 ppm,
s) in HMBC spectrum. The structures both of the major
and minor products of hydrazones transformation also
proved that in phenylhydrazones Va and Vb carbon atoms
of the CHCl group and of the hydrazone moiety are
situated in position 1,4.
As a side product in reaction of phenylhydrazone Va
chlorodiketone IIIa was isolated, and with phenyl-
hydrazone Vb, previously unknown pyridazine VII.
A series of substituted tetrahydropyridazines was
formerly patented as drugs against osteoporosis,
disseminated sclerosis, rheumatoid arthritis, and as
phosphodiesterase inhibitors [5]. The structure of
pyridazine derivative VII was proved by NMR spectro-
scopy. Spectra COSY-45 revealed a fragment CH–CH–
CH2 and four three-proton spin systems of the phenyl
substituents. The neighboring position of the C3H at the
Chlorodiketone IVb unlike analogous chlorodiketone
IIIa and IIIb in reaction with the phenylhydrazine gave
monohydrazone VIII at the carbonyl contiguous to CHCl
group. The hydrazone at heating in methanol saturated
with hydrogen chloride easily transformed into azoolefin
CH3
CH3
CH3
Cl
Cl
3
C6H5NHNH2
CH3OH/HCl
1
C6H5
C6H5
C6H5
C6H5
C6H5
C6H5
O N
NC6H5
O N
O O
NC6H5
H
IVb
VIII
IX
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TRANSFORMATIONS OF STEREOISOMERIC 2-CHLORO-3-R-PENTANE-1,5-DIONES
217
IX. Similar compounds are known to form readily in
1,4-dehydrohalogenation of α-chloroketones phenyl-
hydrazones [6].
Agilent 1100 Series LC/MSD instrument using column
Lichro CART CN (4×250 mm, sorbent size 5 μm) at
thermostat temperature 40°C in a linear gradient elution
mode (30–70% aqueous acetonitrile) at a rate 2% per
min. Elution rate was 0.5 ml/min, detecting by electron
absorption spectra in the range 200–700 nm, electrospray
ionization at atmospheric pressure, mode of positive ions
registering, ionization voltage 70 V, ionizing chamber
voltage 4 kV, gas-drier flow (nitrogen) 6 l/min, gas-solvent
pressure (nitrogen) 50 kg/cm2. The range of registered
masses m/z 150–700. Electron-impact mass spectra were
measured on LKB 9000S instrument with a direct
admission of the sample into the ion source at ionization
voltage 70 V.
The structure of hydrazone VIII got clear after estima-
tion of the structure of the product IX of its transformation
and analysis of the spectral data. For instance, in the
1H NMR spectrum of compound VIII alongside signals
of the aromatic protons at 6.9–7.0 ppm and of NH group
at 7.80 ppm (s) appear also doublets of a methyl group at
1.20 ppm (J 7.0 Hz) and CHCl group at 5.10 ppm
(J 7.6 Hz), and signals of a methylene group [2.70 d
(J 3.0 Hz), 2.74 br.s, ppm] and of a methine proton at
2.81 ppm (m). In the corresponding mass spectrum peaks
are observed of a pseudomolecular ion of m/z 391 [M +
H]+ and of ion of 355 [M + H – HCl]+; the IR spectrum
contains absorption bands of a carbonyl group at
1682 cm–1 and of NH group at 3304 cm–1.
1H NMR spectrum of azoolefin IX lacks the signal
of NH group and contains doublets from a methyl at
1.21 ppm (J 7.0 Hz) and vinyl proton at 5.37 ppm
(J 1.5 Hz). Methylene group and the adjacent methine
proton appear as the following signals, ppm: 2.43 br.d
(2H, J 6 Hz) and 2.73 m (1H). In the electron-impact
mass spectrum of compound IX peaks are observed of
m/z 354 [M]+ and 249 [M – C6H5CO]+, and in the IR
spectrum, absorption bands at 3056, 1690, 1600, 1560,
and 1500 cm–1.
Melting points of compounds synthesized were
measured on a Bo.e.tius heating block. The reaction
progress was monitored and the purity of compounds
synthesized was checked by TLC on Sorbfil plates,
development under UV irradiation or with iodine vapor.
Stereoisomeric 1,3,5-triphenyl-2-chloropentane-1,5-
diones (IIIa and IIIb), and 3-methyl-1,5-diphenyl-2-
chloropentane-1,5-dione (IVb) were obtained by chlorinat-
ing diketones I or II by ΒTMAICl2 in acetic acid or DMF
respectively in keeping with procedure [2].
1,3,5-Diphenyl-2-chloropentane-1,5-diones
phenylhydrazones Va and Vb. To a solution of 0.36 g
(1 mmol) of an appropriate chloroketone IIIa (Rf 0.25)
or IIIb (Rf 0.32) in 8 ml of acetic acid prepared by heating
at 50–55°C was added dropwise at stirring an equimolar
amount of phenylhydrazine (0.11 ml) in 1 ml of ethanol.
The precipitate in 3 h phenylhydrazone was filtered off
and washed with ethanol.
Thus two types of chlorodiketones of a close structure
distinguished by a substituent at C3 atom form mono-
phenylhydrazones regiospecifically either at a remote
(R = Ph) or on the contrary at the close to CHCl carbonyl
group (R = CH3). Consequently these monophenyl-
hydrazones can be transformed either into derivatives of
indole and pyridazine or into azoolefin. Apparently
introducing a chlorine atom into the α-position can
increase the reactivity of a carbonyl, but in the presence
of a bulky substituent at C3 atom the approach to this
carbonyl is sterically hindered by the substituent and
chlorine, and in this event the reaction first of all occurs
at the remote carbonyl.
Phenylhydrazone (Va).Yield 0.27 g (60%), mp 151–
152°C (from ethanol), Rf 0.45 (hexane–ethyl ether–
dichloromethane, 2:0.3:0.1). IR spectrum, ν, cm–1: 1602
(C=N), 1682 (C=O), 3312 (NH). 1H NMR spectrum, δ,
ppm: 3.28 d.d (1H, CH2, J 11.2, 14.3 Hz), 3.5 d.d (1H,
CH2, J 2.4, 14.0 Hz), 3.86 d.d.d (CH, J 2.4, 5.2, 7.6 Hz),
5.58 d (CHCl, J 5.0 z), 6.8–8.0 m (20H, Ar), 8.5 s (NH).
13C NMR spectrum, δ, ppm: 30.85 (C4, CH2), 42.8 (C3,
CH), 60.8 (C2, CH), 113.0 (2CH), 119.8 (CH), 125.7
(4CH), 127.4 (CH), 127.9 (4CH), 128.8 (2CH), 128.9
(2CH), 129.1 (2CH), 134.1 (C), 139.0 (C), 140.0 (C),
138.5 (C), 145.4 (C5), 193.8 (CO). Mass spectrum: m/z
453 [M + H]+. Found, %: C 76.80; H 5.30; N 6.10.
C29H25ClN2O. Calculated, %: C 76.90; H 5.52; N 6.20.
EXPERIMENTAL
1H NMR spectra were registered on spectrometers
Bruker DRX-300 and DRX-500 from solutions in
deuterochloroform, internal reference TMS. IR spectra
were recorded on a spectrophotometer Perkin-Elmer
Spectrum BX-II in dichloromethane. HPLC-MS
measurements were carried out on Hewlett-Packard
Phenylhydrazone (Vb). Yield 0.22 g (49%), mp 158–
159°C (from ethanol), Rf 0.38. IR spectrum, ν, cm–1: 1602
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 43 No. 2 2007

MOSKOVKINA, KALINOVSKII
218
(C=N), 1680 (C=O), 3315 (NH). 1H NMR spectrum, δ,
ppm: 2.90 d.d (1H, CH2, J 3.8, 14.0 Hz), 3.0 d.d (1H,
CH2, J 10.1, 14.0 Hz), 3.96 t.d (CH, J 3.8, 10.2 Hz),
5.54 d (CHCl, J 10.5 Hz), 6.8–8.2 m (20H, Ar), 8.9 s
(NH). 13C NMR spectrum, δ, ppm: 32.3 (C4', CH2), 44.2
(C3', CH), 58.3 (C2', CH), 113.15 (2CH), 119.9 (CH),
125.5 (2CH), 127.2 (CH), 127.75 (2CH), 127.8 (2CH),
128.35 (2CH), 128.7 (2CH), 129.0 (2CH), 129.2 (2CH),
129.4 (2CH), 134.2 (C), 134.25 (CH), 134.6 (CH), 139.0
(C5'), 138.5 (C), 134.7 (C), 140.0 (C), 194.1 (CO). Mass
spectrum (electrospray ionization): m/z 453 [M + H]+.
Found, %: C 76.86; H 5.20; N 6.00. C29H25ClN2O.
Calculated, %: C 76.90; H 5.52; N 6.20.
2,4,6-Triphenyl-3-benzoyl-2,3,4,5-tetra-
hydropyridazine (VII). mp 100–102°C (from ethanol),
Rf 0.30 (hexane–ethyl ether–dichloromethane, 2:0.3:0.1).
IR spectrum, ν, cm–1: 1690 (CO). 1H NMR spectrum, δ,
ppm: 2.74 d.d (1H, CH2, J 7.0, 17.7 Hz), 2.81 d.d (1H,
CH2, J 1.6, 7.0 Hz), 3.82 d.t (CH, J 1.5, 7.0 Hz), 5.71 t
(CH–N, J 1.3 Hz), 6.87 t.t (CH, Ar, J 1.2, 7.0 Hz), 7.25–
7.29 m (10 CH, Ar), 7.37 t.t (2CH, Ar, J 1.7, 6.7 Hz),
7.57 t.t (2CH, Ar, J 1.7, 7.6 Hz), 7.68 t.t (CH, Ar, J 1.8,
7.5 Hz), 7.83 d.t (2CH, Ar, J 1.2, 7.1 Hz), 8.11 d.t (2CH,
Ar, J 1.4, 7.1 Hz). 13C NMR spectrum, δ, ppm: 24.4
(CH2), 36.1 (CH), 63.1 (CH–N), 114.2 (2CH, Ar), 120.6
(2CH,Ar), 124.9 (2CH,Ar), 126.9 (2CH,Ar), 127.4 (CH,
Ar), 127.8 (CH, Ar), 128.2 (2CH, Ar), 128.5 (2CH, Ar),
129.0 (2CH,Ar), 129.1 (2CH,Ar), 129.3 (2CH,Ar), 133.8
(C), 134.0 (CH, Ar), 137.4 (C), 138.5 (C), 142.7 (C),
147.0 (C), 196.5 (CO). Mass spectrum: m/z 417 [M +
H]+. Found, %: C 83.36; H 5.52; N 6.60. C29H24N2O.
Calculated, %: C 83.65; H 5.76; N 6.73.
2-Amino-1,3-diphenyl-3-(2-phenylindolyl-3)-
propan-1-one (VI). In ethanol solution 0.226 g (0.5 mmol)
of an appropriate hydrazone Va or Vb was heated at
reflux for 15 h, then the solution was cooled, in reaction
with phenylhydrazone Vb the precipitate of pyridazine
VII was filtered off. On distilling off the solvent 10 ml of
ethyl ether was added to the residue. The insoluble
precipitate of tryptamine VI hydrochloride was filtered
off. Yield of compound VI from hydrazone Va 0.1 g
(47%), from hydrazone Vb, 0.061 g (30%). The
hydrochloride was treated with water solution of Na2CO3,
base VI was extracted into ethyl acetate (2×10 ml). The
extract was dried over MgSO4, the solvent was distilled
off, 0.5 ml of ethanol was added to the residue, the
precipitate was filtered off to obtain compound VI, mp
170–172°C, Rf 0.22 (hexane–ethyl acetate, 2:1). IR
spectrum, ν, cm–1: 1680 (C=O), 3308, 3372 (NH2), 3460
3-Methyl-1,5-diphenyl-2-chloropentane-1,5-
dione phenylhydrazone (VIII). To a solution of 0.5 g
(1.7 mmol) of diketone IVb in 4 ml of acetic acid was
added 0.184 g (1.7 mmol) of phenylhydrazine in 1 ml of
ethanol. The solution was stirred by a magnetic stirrer
for 1 h. The precipitate of hydrazone VIII separated after
standing for 10 h at room temperature was filtered off,
washed with 3 ml of acetic acid and 3 ml of ethanol.
Yield 0.43 g (66%), mp 133–134°C (from ethanol),
Rf 0.45 (hexane–ethyl ether–chloroform, 2:0.3:0.1). IR
spectrum, ν, cm–1: 1682 cm-1 (CO), 3304 (NH). 1H NMR
spectrum, δ, ppm: 1.2 d (CH3, J 7.0 Hz), 2.70 d (1H,
J 3.0 Hz), 2.74 br.C (1H), 2.81 m (1H), 5.1 d (CHCl,
J 7.6 Hz), 6.9–7.0 m (ArH), 7.8 C (NH). Mass spectrum:
m/z 391 [M + H]+, 355 [M + H – HCl]+. Found, %:
C 73.60; H 5.70; N 7.00. C24H23ClN2O. Calculated, %:
C 73.75; H 5.88; N 7.17.
1
(NH of indole ring). H NMR spectrum, δ, ppm: 4.87 d
(C3H, J 8.6 Hz), 5.50 d (C2H, J 8.6 Hz), 7.05 t (CH,
J 7.4 Hz), 7.14 t (2CH, J 7.8 Hz), 7.16 t (CH, J 7.0 Hz),
7.25–7.27 m (6CH), 7.35 m (2CH), 7.40 d (CH,
J 6.8 Hz), 7.41 d (CH, J 7.7 Hz), 7.42 d (2CH, J 7.0 Hz),
7.69 d (2CH, J 7.0 Hz), 7.84 d (CH, J 8.0 Hz), 8.21 s
(NH). 13C NMR spectrum, δ, ppm: 48.4 (CH), 58.2 (CH),
111.2 (C), 111.3 (CH), 120.3 (CH), 121.0 (CH), 122.3
(CH), 126.3 (CH), 128.25 (5CH), 128.45 (2CH), 128.7
(CH), 128.35 (2CH), 128.7 (2CH), 128.8 (2CH), 129.7
(C), 132.6 (C), 132.7 (CH), 136.1 (C), 136.4 (C), 137.8
(C), 142.3 (C), 202.1 (CO). Mass spectrum: m/z 417
[M + H]+. Found, %: C 83.45; H 5.65; N 6.50.
C29H24N2O. Calculated, %: C 83.65; H 5.76; N 6.73.
Ethyl ether was evaporated from the mother liquor after
separating tryptamine VI hydrochloride obtained in
reaction with phenylhydrazone Vb to get an oily substance
that slowly crystallized under ethanol. The crystals were
filtered off to obtain 0.12 g (53%) of chlorodiketone IIIb
identified by direct comparison with an authentic sample.
3-Methyl-1,5-diphenyl-5-phenylazopent-4-en-1-
one (IX). A solution of 0.9 (2.3 mmol) of hydrazone
VIII in 10 ml of methanol saturated with hydrogen
chloride was heated on a water bath for 7 h and left
standing at room temperature for 18 h. The separated
viscous substance was isolated, crystallized by adding
a mixture ethanol–ethyl ether, 2:1, and recrystallized from
ethanol. Yield 0.24 g (30%), yellow crystals, mp 142–
144°C, Rf 0.52 (hexane–ethyl ether–chloroform,
2:0.3:0.1). IR spectrum, ν, cm–1: 1500, 1560, 1600, 1690
(CO), 3056. 1H NMR spectrum, δ, ppm: 1.21 d (CH3,
J 7.0 Hz), 2.43 br.d (CH2, J 6 Hz), 2.73 m (CH), 5.37 d
(CH=, J 1.5 Hz). Mass spectrum, m/z (electron impact):
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 43 No. 2 2007

TRANSFORMATIONS OF STEREOISOMERIC 2-CHLORO-3-R-PENTANE-1,5-DIONES
219
354 [M]+, 249. Found, %: C 81.10; H 5.75; N 8.80.
Khim., 1994, vol. 30, p. 996.
3. Grandberg, I.I., Izv. Akad. Nauk SSSR,Ser. Khim., 1966,
p. 1682; , Grandberg, I.I., Afonina, N.I., and Zuyanova, T.I.,
Khim. Geterotsikl. Soedin., 1968, p. 1038.
4. Grandberg, I.I. and Zuyanova, T.I., Khim. Geterotsikl.
Soedin., 1970, p. 750.
5. Rochus, J., Wolf, M., Beier, N., Kluxen, F., and Fittschen, C.,
German Patent 59484, 2000; Chem. Abstr., 2000, vol. 133,
301117a; Shibata, T., Tamaki, K., Tanazawa, K., and Kura-
kata, S., Japan Patent 163862, 2001; Chem.Abstr., 2001,
vol. 135, 46189c.
C24H21N2O. Calculated, %: C 81.21; H 5.93; N 8.92.
REFERENCES
1. Kharchenko, V.G., Chalaya, S.N., Litvinov, O.V., Yudo-
vich, L.M., and Promonenkov, V.K., Zh. Org. Khim., 1984,
vol. 20, p. 1208; Litvinov, O.V., Kolyagin, N.T., Chalaya, S.N.,
Kharchenko, V.G., Yanovskii,A.I., and Struchkov, M.T., Zh.
Org. Khim., 1989, vol. 25, p. 34.
2. Moskovkina, T.V. and Vysotskii, V.I., Zh. Org. Khim., 1991,
vol. 27, p. 833; Moskovkina, T.V. and Vysotskii, V.I., Zh. Org.
6. Kitaev, Yu.P. and Buzykin, B.I., Gidrazony (Hydrazones),
Moscow: Nauka, 1974, p. 370.
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