Synthesis, structure, and characteristics of 1,2-dichlorovinyl alkyl ketones

Article abstract of DOI:10.1007/s11178-005-0064-7

A method of alkyl 1,2-dichlorovinyl ketones preparation from acyl halides and 1,2-dichloroethylene was developed. The configurational equilibrium and electronic structure of alkyl 1,2-dichlorovinyl ketones was investigated by IR, ¹H and ¹³C NMR spectroscopy, by measuring dipole moments, and by quantum-chemical calculations using methods RHF and B3LYP in the basis 6-311++G (d,p). Alkyl 1,2-dichlorovinyl ketones are stable in the Z, s-cis-configuration where the olefin proton is involved into an intramolecular hydrogen bond with the oxygen of the carbonyl group. Reaction of 1,2-dichlorovinyl ketones with alkylhydrazines afforded 1-alkyl-3-alkyl-4- chloropyrazoles. The reaction of alkyl 1,2-dichlorovinyl ketones with 1,1-dimethylhydrazine involved dehydrochlorination and afforded 1,1-dimethylhydrazinium hydrochloride and a mixture of compounds with uncertain structure. 2004 MAIK "Nauka/Interperiodica".

Full text of DOI:10.1007/s11178-005-0064-7

Russian Journal of Organic Chemistry, Vol. 40, No. 11, 2004, pp. 1583 -1592. Translated from Zhurnal Organicheskoi Khimii, Vol. 40, No. 11,
004, pp. 1632-1640.
2
Original Russian Text Copyright Ó 2004 by Bozhenkov, Leckovskaya, Larina,Ushakov, Dolgushin,Mirskova.
Synthesis, Structure, and Characteristics of 1,2-Dichlorovinyl
Alkyl Ketones
G.V. Bozhenkov, G.G. Leckovskaya, L.I. Larina, P.E. Ushakov,
G.V. Dolgushin, andA.N. Mirskova
Faworsky Irkutsk Institute of Chemistry, Siberian Division, Russian Academy of Sciences
Irkutsk, 664033, Russia (3952)396046
e-mail: ggl@irioch.irk.ru
Received April 15, 2003
Abstract--A method of alkyl 1,2-dichlorovinyl ketones preparation from acyl halides and 1,2-dichloroethylene
was developed. The configurational equilibrium and electronic structure of alkyl 1,2-dichlorovinyl ketones was
1
13
investigated by IR, H and C NMR spectroscopy, by measuring dipole moments, and by quantum-chemical
calculations using methods RHF and B3LYPin the basis 6-311++ G (d,p).Alkyl 1,2-dichlorovinyl ketones are stable
in the Z,s-cis-configuration where the olefin proton is involved into an intramolecular hydrogen bond with the
oxygen of the carbonyl group. Reaction of 1,2-dichlorovinyl ketones with alkylhydrazines afforded 1-alkyl-3-alkyl-
4
-chloropyrazoles. The reaction of alkyl 1,2-dichlorovinyl ketones with 1,1-dimethylhydrazine involved
dehydrochlorination and afforded 1,1-dimethylhydrazinium hydrochloride and a mixture of compounds with
uncertain structure.
Chlorovinyl ketones are extremely important and
promising semiproducts for syntheses of quite a number
of polyfunctional highly reactive and heterocyclic com-
pounds [1]. With a goal to find a convenient procedure
for preparation of a number of heterocyclic compounds,
among them 1-alkyl-4-chlorosubstituted pyrazoles
analogously to [2], and also to reveal the difference in
the chemical properties of 1,2-dichlorovinyl ketones and
their isostructural analogs, 2,2-dichlorovinyl ketones we
have developed a method of synthesis for alkyl 1,2-di-
chlorovinyl ketones and report here on this method and
the study of chemical properties and structure of these
ketones. A comparative analysis of the structural param-
eters and reactivity of these compounds was also per-
formed relative to similar data for 2-chloro- and 2,2-di-
chlorovinyl ketones
transformation of the product of phenyl(dimethylamino)-
acetonitrile dichlorovinylation by boiling for 15 min in
ethanol in the presence of Cu(II) sulfate pentohydrate
[6].
While up till now a single acyclic 1,2-dichlorovinyl
ketone was known, dichloromethyl 1,2-dichlorovinyl
ketone [3] obtained from the corresponding acyl chloride
and cis-1,2-dichloroethylene in the presence of aluminum
chloride at 35°C within 40 h, we developed in this study
preparation procedure and synthesized metyl, ethyl, and
propyl 1,2-dichlorovinyl ketones in up to 90% yield.
$
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Alk = Me (I, IV), Et (II, V), Pr (III, VI).
,
$
+&O
,
Prior to this study the following compounds were
reported: dichloromethyl [3], phenyl 1,2-dichlorovinyl
ketones [4], and a number of cyclic 2,3-dichloroenones-1
Under conditions used in the synthesis of dichloro-
methyl 1,2-dichlorovinyl ketone [3] but applying the
commercially produced mixture of cis- and trans-1,2-
dichloroethenes methyl and propyl 1,2-dichlorovinyl
ketones were obtained in the yield not exceeding 24%.
[
1
1, 5]. The phenyl ketone was obtained by reaction of
,2-dichloroacryloyl chloride with benzene in the presence
of aluminum chloride [4]. It also was reported that this
compound was prepared in an 80% yield as a result of
1070-4280/04/4011-1583Ó2004 MAIK “Nauka/Interperiodica”

1584
BOZHENKOV et al.
Under conditions we developed the reaction is carried
afford pyrones [8]. The structure of ketones I–III was
established by physicochemical methods and confirmed
by elemental analysis.
out by heating for 6 h at 60°C the corresponding acyl
chloride with the mixture of cis- and trans-1,2-
dichloroethenes in the presence of anhydrous aluminum
chloride at the reagents ratio 1:10:1. On completing the
reaction the products were subjected to distillation to
isolate and characterize the mixture of substances: the
corresponding 1,2-dichlorovinyl ketones I–III, and 1,2,2-
trichloroethyl alkyl ketones IV–VI. The treating of the
reaction mixture with bases without heating or steam
distillation analogously to preparation procedures for 2-
chloro- and 2,2-dichlorovinyl ketones from 2,2-dichloro-
and 2,2,2-trichloroethyl ketones [1, 7] did not result in a
complete conversion of 1,2,2-trichloroethyl alkyl ketones
IV–VI into 1,2-dichlorovinyl ketones. Exhaustive
dehydrochlorination of 1,2,2-trichloroethyl alkyl ketones
IV–VI succeeded on prolonged heating of the reaction
mixture at 80–90°C in the presence of aqueous sodium
carbonate.
1
In the H NMR spectra of 1,2-dichlorovinyl ketones
I–III as also in those of 2,2-dichlorovinyl ketones and
2,2-dibromovinyl fluoromethyl ketone [9, 10] a singlet from
olefin proton is observed. Note that the chemical shift of
the olefin proton in the spectrum of phenyl 1,2-di-
chlorovinyl ketone (d 6.39 ppm) reported in [6] is not in
agreement with the chemical shifts of =CH in alkyl
ketones I–III (d 7.54–7.56 ppm) observed in the present
study.
1
The singlet of the b-proton in the H NMR spectra
and also the single narrow absorption band of the carbonyl
group in the IR spectra of 1,2-dichlorovinyl ketones I–
III evidence their geometrical and in all likelihood
conformational uniformity.
We previously studied conformational structure of
important organic compounds, alkyl(aryl) 2,2-dichlorovinyl
ketones and trifluoromethyl 2,2-dibromovinyl ketones by
means of quantum-chemical calculations along SCF MO
LCAO method using semiempirical CNDO/2 procedure,
method B3LYP/6-311 G (d,p), calculations of atomic
oscillations, measurements of dipole moments, IR, UV,
At the same time these severe conditions were not fit
for preparation of pure chloromethyl and trichloromethyl
,2-dichlorovinyl ketones in reaction of monochloro- and
trichloracetyl chlorides with 1,2-dichloroethylene. The
trichloroethyl ketones formed in the first reaction stage
when treated with bases at heating suffered hydrolysis
involving the chloromethyl moiety and afforded a mixture
of products containing among them the corresponding
1
1
35
H NMR, and Cl NQR spectroscopy [9–12].
In the present research the structure of alkyl 1,2-di-
chlorovinyl ketones I–III and the conformational
1
,2-dichlorovinyl derivatives as showed the resonances
equilibrium in their molecules were investigated by IR
1
1
at 7.6–8.0 ppm in the H NMR spectrum of the reaction
mixture. We also failed to isolate pure products of the
reaction with dichloroethylene of benzoyl and 4-chloro-
benzoyl chlorides. The studies on the synthesis of
chloromethyl and aryl 1,2-dichlorovinyl ketones are in
progress.
and H NMR spectroscopy, measurements of dipole
moments, and by quantum-chemical calculations using
methods RHF and B3LYP in the basis 6-311++ G (d,p)
[13] (Tables 1 and 2). The results obtained were compared
with previous calculations for the 2,2-dichloro(bromo)vinyl
ketones [12].
1
In the H NMR spectra of 1,2-dichlorovinyl ketones
We did not isolate individual tichloroethyl ketones IV–
VI for they decomposed during distillation, but the
I–III is observed a singlet from the b-protone displaced
1
downfield by ~1 ppm with respect to the singlet from
compounds were characterized by IR and H NMR
1
the a-vinyl proton in the H NMR spectrum of the
spectra. In the IR spectra of compounds IV–VI the
frequency and intensity of the absorption bands of
carbonyl stretching vibrations are higher than in the
corresponding spectra of 1,2-dichlorovinyl ketones. In the
2
,2-di-chlorovinyl analogs [10], and its chemical shift
is close to the values of the signal from the b-olefin
proton in the spectrum of methyl 2-chlorovinyl ketone
1
(
(
XIV) [ H NMR spectrum (CDCl ), d, ppm: 7.26 d
3
1
H NMR spectra of ketones IV–VI appeared two
=CHCl, 1H, J 13.9 Hz), 6.45 d (=CH, 1H, J 13.9 Hz),
characteristic proton doublets from CHCl and CHCl
2
2
.25 s (CH , 3H)] and chloromethyl 2-chlorovinyl
3
groups and the signals from the protons of alkyl moieties.
1
ketone (XV) [ H NMR spectrum (CDCl ), d, ppm:
7.49 d (=CHCl, 1H, J 13.9 Hz), 6.76 d (=CH, 1H,
3
The synthesized 1,2-dichlorovinyl ketones I–III are
colorless liquids that in contrast to 2-chloro- and 2,2-di-
chlorovinyl ketones are relatively stable, do not turn dark
at storage for a month under common conditions and do
not undergo at long storage the dehydrochlorination to
J 13.9 Hz), 4.19 s (CH Cl, 2H)].
2
The more downfield chemical shift of the olefin proton
1
in the H NMR spectrum of ketones I–III is well
consistent with the known trend to downfield displacement
RUSSIAN JOURNALOF ORGANIC CHEMISTRY Vol. 40 No. 11 2004

SYNTHESIS, STRUCTURE, AND CHARACTERISTICS OF 1,2-DICHLOROVINYL ALKYLKETONES
1585
Table 1. Experimentally measured and calculated [B3LYP/6-311++G(d,p), RHF/6-311++G(d,p)] dipole moments and chemical
1
13
shifts of H and C for E- and Z-isomers of 1,2-dichlorovinyl ethyl ketone
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Table 2. Total charges on atoms (Q, e) and bond lengths (l, A) calculated {B3LYP/6-311++G (D,P), RHF/6-311++G (d, p}for
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of the proton signal on the introduction of a geminal by their existence in the form of a single isomer and a
chlorine atom into the vinyl structure. The expected single rotational conformer. Therewith in the IR spectra
downfield shift of the olefin b-proton signal in going from of ketones I–III the observed stretching vibration bands
2
-chlorovinyl ketones to 1,2-dichlorovinyl ketones was
of the carbonyl group (1690–1695 cm ) and the double
–1
also registered.
bond are located in the region corresponding to the high-
The presence in the vibration spectra of alkyl 1,2-di- frequency component in the spectra of alkyl 2,2-di-
–
1
chlorovinyl ketones I–III of narrow bands in the chlorovinyl ketones (1705 cm ) [12] belonging to the
absorption region of C=O and C=C groups is likely caused carbonyl vibrations of the s-cis-isomer. It was formerly
RUSSIAN JOURNALOF ORGANIC CHEMISTRY Vol. 40 No. 11 2004

1586
BOZHENKOV et al.
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established that the dichloro(bromo)vinyl ketones existed
as a mixture of two s-cis-, s-trans-conformers [12]. It
should be indicated that in the cyclic 1,2-dichloroenones
with the fixed Z,s-trans-form the band of stretching
vibrations nC=O is shifted by ~~ 40–50 cm to the higher
frequencies [5] compared with the analogous band in the
IR spectra of ketones I–III.
with that of the E,s-trans-isomer of ketone II. The dipole
moment of ketone II measured in benzene solution under
standard conditions and equal to 2.6 D corresponds to
the calculated value for trans-isomer in an s-cis-form of
compound II (Table 1). This deviation of calculated values
from the experimental data requires independent
determination of the structure and elucidation of the reason
of this discrepancy (e.g., the influence of the medium
should be taken into consideration).
–
1
The data of calculations performed in this study indicate
that the planar Z,s-cis-structure of 1,2-dichlorovinyl
ketone II is more favorable than non-planar (jOCC Cb
1
a
The data of H NMR spectra for methyl and chloro-
~
90°) s-trans-conformer of isomer of this compound
methyl 2-chlorovinyl ketones (XIV and XV respectively)
that we prepared ftom acetylene and the corresponding
acyl chlorides according to [1] also showed that in these
ketones a single isomer was present, and the stabilization
of the observed E-isomer (JH–H ~~ 14 Hz) was apparently
ensured by an intramolecular hydrogen bond.
-
1
by 4.57 (RHF) and 5.78 (B3LYP) kcal mol .
It is presumable that in the Z,s-cis-structure II is
.
..
present an intramolecular hydrogen bond (C=O H)
between the carbonyl oxygen and vinyl proton. This
assumption is supported by the value of the distance
°
between these atoms amounting to ~2.44 A that is greater
The calculations obtained in this study evidence a
significant polarization of the double bond to the direction
of C in the E,Z-isomers of 1,2-dichlorovinyl ketones.
The total charge on this atom in the Z-isomer is close to
1, and on the atom C it amounts to ~+1.Asimilar charge
distribution on the respective atoms but with somewhat
smaller absolute values is observed in the E-isomer.
Interestingly, the calculation procedures applied suggest
that in the E- and Z-isomers of ketone II the charges on
°
than the sum of their covalent radii (0.99 A) [14] but
°
less than the sum of the van der Waals radii (2.72 A)
b
[15] (Table 2). Besides the C=O and C–H bonds of this
conformer are somewhat longer that those in the s-trans-
conformer of the E-isomer (Table 2). The negative
charge on the oxygen is larger in the planar s-cis- than in
s-trans-conformer (Table 2). The same trend is observed
in the change in the conformers of the positive charge on
the hydrogen of the vinyl fragment thus facilitating the
formation of the intramolecular hydrogen bond. For
instance, the calculated chemical shift of the vinyl proton
in the Z,s-cis-structure of ketone II is located in a weaker
field than that of the trans-structure (Ddcalc 1.71 ppm)
a
–
3
the carbon atoms of the carbonyl group C are negative,
and on the both chlorine atoms they are positive; the
charge distribution obtained for ketone II is virtually
independent of the calculation procedure.
We studied the behavior of 1,2-dichlorovinyl ketones
I–III in reactions with some nucleophiles aiming
at elucidating the difference and analogy with the
(Table 1).
1
The calculated chemical shifts of H for Z,s-cis-isomer
of ketone II more often coincide with the experimental
data (Table 1). For instance, the calculated chemical shift
value for the vinyl proton in the Z,s-cis-structure of
ketone II and also dC (C=O) are closer to the
2
-chloro-, 2,2-dichloro(bromo)vinyl ketones.
Ketones I–III reacted with dinitrophenylhydrazine
yielding the corresponding alkyl 1,2-dichlorovinyl ketones
hydrazones VII–IX. In the H NMR spectra of hydr-
azones VII–IX the signals of the benzene ring protons
with the characteristic splitting were observed. The
coupling of H –H protons was also revealed. The olefin
1
experimental data than the calculated d (=C–H) and
H
dC (C=O) for the trans-structure (Table 1). At the same
time the experimentally measured chemical shift value
b
3
5
for the b-carbon atoms d (C ) is in better agreement
C
RUSSIAN JOURNALOF ORGANIC CHEMISTRY Vol. 40 No. 11 2004

SYNTHESIS, STRUCTURE, AND CHARACTERISTICS OF 1,2-DICHLOROVINYL ALKYLKETONES
&&&O &+&Oꢀꢀꢁꢀꢀ1+ 1+5ꢂ
1587
5
2
&O
+
5
&O
&O
5
(
W 1
5
&O
1
&O
1
(
W 1ꢀꢀ+&O
1
1
5ꢂ
1
1
+5ꢂ
5ꢂ
+
;
;,,,
X, R = Me, R' = C H ; XI, R = R' = Et; XII, R = Et, R' = Bn; XIII, R = C H , R' = Et.
7
15
7
15
proton appeared as a singlet indicating the existence of
nitrophenylhydrazones VII–IX in the form of a single
isomer in contrast to the analogous 2,2-dichlorovinyl
ketones hydrazones [16]. It was established that similarly
to the 2,2-dichlorovinyl alkyl ketones dinitrophenylhydr-
azones [16] hydrazones VII–IX did not undergo
cyclization into pyrazoles when treated with bases in
alcohols, in DMSO, in DMF or at thermolysis.
XI and XII the proton signals from the methylene
group at the nitrogen atom are located downfield with
respect to the signals from NCH group in 1-heptylpyr-
2
azole (X).
4
-Chloropyrazoles are promising for manufacturing
drugs, dyes, fluorescents, insecticides, insectoacaricides,
and other biologically active compounds. For instance,
the derivatives of 4-chloropyrazoles served for preparation
of an acaricide tebufenpyrad, highly efficient preparation
against herbivorous ticks at every stage of their
development, and for preparation of an insecticide of wide
application OMI-88 [17]. Thus the development of
preparation procedures for 4-chloropyrazoles based on
available products is obviously an important task.
In reaction of 1,2-dichlorovinyl ketones with alkylhydr-
azines we isolated 1-alkyl-4-chloropyrazoles X–XIII in
reproducible high yields. No alkylhydrazones were
obtained no matter under what conditions the process
was carried out: in aprotic or proton-donor solvents, at
different molar ratio of the reagents and at various low
temperatures (from –70 to 20°C).
We recently found a new reaction of selective
heterocyclization of the accessible 2-chloro-, 2,2-di-
chlorovinyl ketones and trifluoromethyl 2,2-dibromovinyl
ketone effected by 1,1-dimethylhydrazine furnishing
1-methyl-3-R-pyrazoles and 1-methyl-3-R-5-chloro-
(bromo)pyrazoles [2, 9, 10]. In order to reveal the degree
of generality and the rules governing the new reaction in
this study we brought into the process with the 1,1-di-
methylhydrazine the newly synthesized alkyl 1,2-di-
chlorovinyl ketones.
Pyrazoles X–XIII are liquids with a characteristic
mould odor, soluble in organic solvents.
The structure of pyrazoles X–XIII was proved by
physicochemical methods, the composition was confirmed
by elemental analysis.
In the IR spectra of 1-alkyl-4-chloropyrazoles X–
XIII the presence of a band should be indicated in the
region 3125–3150 cm–1 characteristic of the stretching
5
vibrations of the C –H bond of the heterocycle. The
absorption bands of the C=C bonds of the heterocycle
appeared in the IR spectra at 1470–1575 cm .
Unlike dichloroacrolein or 2,2-dichlorovinyl ketones [2,
18] the alkyl 1,2-dichlorovinyl ketones in the reaction with
1,1-dimethylhydrazine did not give rise either to ketones
I–III dimethylhydrazones or to the corresponding
–
1
1
In the H NMR spectra of pyrazoles X–XIII the
5
resonance signals of protons H appear in the region
1-methyl-3-alkyl-4-chloropyrazoles.
7
.23–7.27 ppm with a downfield shift of 0.6–1.3 ppm as
4
compared to the H signals of their 5-chloro-substituted
analogs (5.92–6.58 ppm). The dependence of the
The reaction of alkyl 1,2-dichlorovinyl ketones I–III
with 1,1-dimethylhydrazine afforded a precipitate of
1,1-dimethylhydrazine hydrochloride (XIV) and an
intractable mixture of substances, while in reaction of
chemical shift for the protons in the NCH R' group is a
2
1
lot weaker. In the H NMR spectrum of 1-ethylpyrazoles
RUSSIAN JOURNALOF ORGANIC CHEMISTRY Vol. 40 No. 11 2004

1588
BOZHENKOV et al.
1
unsymmetrical dimethylhydrazine with the isostructural
analogs of the ketones under study, 2,2-dichlorovinyl
ketones [2], were isolated trimethylhydrazinium chloride
and 1-methyl-3-R-5-chloropyrazoles. In the IR spectrum
of the isolated salt XIV appeared the bands of stretching
Inasmuch as in the H NMR spectra of the reaction
products obtained from ketones I–III and 1,1-dimethyl-
hydrazine after separation of the dimethylhydrazine
hydrochloride groups of signals were observed in the
regions 3.6–4.0 and 7.2–7.5 ppm it is presumable that
among the compounds of unknown structure were present
1-methyl-4-chloropyrazoles. The reaction carried out at
cooling, in the presence of triethylamine, or at the double
excess of the dimethylhydrazine also did not permit
isolation of 1-methyl-4-chloropyrazoles or dimethylhydr-
azones. Since the 1-methyl-3-alkyl-4-chloropyrazoles are
stable compounds the above findings indicate that
–
1
vibrations of the CH (2950, 3000 cm ) and NH bonds
–
1
1
(
3130, 3250 cm ). The H NMR spectrum of 1,1-
dimethylhydrazine hydrochloride (XIV) in CD OD the
3
methyl group protons appeared as a singlet at 2.96 ppm
1
while in the H NMR spectrum of trimethylhydrazinium
chloride [19] in CD OD the methyl group protons were
3
shifted downfield, dMe 3.41 ppm.
&O
5
1
1
&+
2
5
&ꢀ2ꢁ&&O &+&Oꢀꢀꢂꢀꢀ0H 11+
5&&&O &+10H 1+ ꢀꢀ&O
1+ 1+0H ꢀꢀ&Oꢀꢀꢂꢀꢀ"
2
5&& &+&O
1+ 1+0H ꢀꢀ&Oꢀꢀꢀꢂꢀꢀ"
10H 1+ ꢀꢀ&O
reactions between 1,1-dimethylhydrazine and 1-chloro-,
of their reactions with dinitro- and monoalkylhydrazines
to the analogous reactions with 2,2-dichlorovinyl ketones
was demonstrated. To reveal the limits of applicability
of the developed synthetic procedure for 1,2-dichlorovinyl
ketones and to disclosure the difference in the chemical
properties of useful synthons, 1,2-dichlorovinyl ketones
and their isostructural analogs 2,2-dichlorovinyl ketones
is of primary importance.
2
1
,2-dichloro(bromo)vinyl ketones on the one hand and
,2-dichlorovinyl ketones on the other hand follow different
mechanisms. The 1,2-dichlorovinyl ketones in contrast
to their isostractural analogs and 2,2-dibromo- and
2
-chlorovinyl ketones in reaction with dimethylhydrazine
first suffer a halogen atom substitution to give unstable
,1-dimethyl-2-(2-acyl-2-chlorovinyl)-hydrazinium
1
chlorides or 1,1-dimethyl-2-(1-acyl-2-chlorovinyl)-
hydrazinium chlorides that decompose with separation
of the dimethylhydrazine hydrochloride and a carbonyl
compound of unknown structure. The investigation of the
reaction is in progress.
EXPERIMENTAL
1H and 13C NMR spectra were registered on
spectrometer Bruker DPX-400 (400.13 and 100.61 MHz
respectively), internal reference HMDS. IR spectra were
recorded on spectrophotometer Specord IR-75 from
samples as microfilms or KBr pellets. 1-Chlorovinyl
ketones XIV and XV were prepared by known procedure
[20].
Hence we developed a procedure for preparation of
1
1
,2-dichlorovinyl alkyl ketones from acyl chlorides and
,2-dichloroethylene in the presence of aluminum chloride.
The strudture of 1,2-dichlorovinyl alkyl ketones was
1
investigated with the use of H NMR and IR spectro-
scopy and quantum-chemical calculations. The similarity
RUSSIAN JOURNALOF ORGANIC CHEMISTRY Vol. 40 No. 11 2004

SYNTHESIS, STRUCTURE, AND CHARACTERISTICS OF 1,2-DICHLOROVINYL ALKYLKETONES
1589
Ethyl 1,2-dichlorovinyl ketone (II). To a stirred
dispersion of 46.7 g (0.35 mol) of anhydrous aluminum
chloride in 50.1 g (0.52 mol) of 1,2-dichloroethylene was
slowly added 32.44 g (0.35 mol) of freshly distilled
propionyl chloride. The reaction mixture was stirred and
heated at reflux for 7–8 h. Then it was cooled and poured
on 300–400 g of crushed ice. The organic layer was
separated, the water layer was extracted with chloroform
mixture. To a stirred dispersion of 26.67 g (0.2 mol) of
anhydrous aluminum chloride in 50 ml of dichloroethylene
was slowly added dropwise 15.70 g (0.2 mol) of acetyl
chloride. The reaction mixture was stirred for 7 h at reflux.
Then it was cooled and poured on 300 g of crushed ice.
The organic layer was separated, the water layer was
extracted with chloroform. The combined organic
solutions were dried on CaCl and distilled in a vacuum
2
(
2×50 ml). The combined organic solution was stirred at
collecting the fraction of bp 47–75°C (5 mm Hg)
amounting to 20 g and consisting of methyl 1,2-
dichlorovinyl ketone (I) and methyl 1,2,2-trichloroethyl
ketone (IV) at a ratio 2:3. Compound IV. IR spectrum, n,
heating to 80–90°C with a water solution of Na CO (pH
1
in a separating funnel and dried with MgSO . The
vacuum distillation furnished 42.85 g(90%) of target
reaction product II, bp 60°C (21 mm Hg), n 1.4945.
IR spectrum, n, cm : 1560 (C=C), 1695 (C=O), 3080
(
(
2
3
2) for 1 h. On cooling the organic layer was separated
4
–
1
1
cm : 1720 (C=O). H NMR spectrum (CDCl ), d, ppm:
3
2
0
6.09 d (1H, CHCl , J 6.28 Hz), 4.60 d (1H, CHCl, J
D
2
–
1
6.28 Hz) 2.40 s (3H, CH3).
1
=C–H). H NMR spectrum (CDCl ), d, ppm: 7.54 s
3
Synthesis of ethyl 1,2,2-trichloroethyl ketone (V)
and ethyl 1,2-dichlorovinyl ketone (II) mixture.
Likewise from 18.51 g (0.2 mol) of propionyl chloride,
26.67 g (0.2 mol) of anhydrous aluminum chloride, and
1H, =CH), 2.80 q (2H, CH , J 7.16 Hz), 1.13 t (3H,
2
CH , J 7.16 Hz); (DMSO-d ): 8.27 s (1H, =CH), 2.85 q
(
3
6
1
3
2H, CH , J 7.2 Hz), 1.01 t (3H, CH , J 7.2 Hz).
C
2
3
NMR spectrum, d, ppm: 192.43 (C=O), 134.83 (=CCl),
30. 64 (=CHCl), 40.73 (CH ), 17.50 (CH ), 13.35
50 ml of dichloroethylene was obtained 26.7 g of a mixture
1
2
2
of ethyl 1,2-dichlorovinyl ketone (II) and ethyl 1,2,2-
trichloroethyl ketone (V) at a ratio 1:7, bp 92–98°C (30
(CH ). Found, %: C 39.62; H 3.95; Cl 46.31. C H Cl O.
3 5 6 2
Calculated, %: C 39.48; H 3.98; Cl 46.02.
–1
mm Hg). Compound V. IR spectrum, n, cm : 1720
1
Methyl 1,2-dichlorovinyl ketone (I) was obtained
in a similar way from 30.99 g (0.395 mol) of acetyl
chloride, 52.64 g (0.395 mol) of aluminum chloride, and
(C=O). H NMR spectrum (CDCl3), d, ppm: 6.09 d (1H,
CHCl , J 6.57 Hz), 4.59 d (1H, CHCl, J 6.57 Hz), 2.75
q
2
(
2H, CH , J 7.13 Hz), 1.09 t (3H, CH , J 7.13 Hz).
2 3
4
5
1
0 ml of dichloroethylene. Yield 47.2 g (86%), bp 55–
Synthesis of propyl 1,2,2-trichloroethyl ketone
8°C (18 mm Hg), n D2 0 1.4965. IR spectrum, n, cm :
–1
(VI) and propyl 1,2-dichlorovinyl ketone (III)
mixture. Likewise from reaction products of 21.31 g
(0.2 mol) of butyryl chloride, 26.67 g (0.2 mol) of
anhydrous aluminum chloride, and 50 ml of
dichloroethylene was isolated a fraction of bp 52–65°C
(2–3 mm Hg) weighing 26 g composed of 1,2-
dichlorovinyl propyl ketone (III) and propyl 1,2,2-
trichloroethyl ketone (VI) at a ratio 1:5 respectively.
1
510 (C=C), 1690 (C=O), 3070 (=C–H). H NMR
spectrum (CDCl ), d, ppm: 7.56 s (1H, =CH), 2.45 s (3H,
CH ). C NMR spectrum, d, ppm: 189.95 (C=O), 135.09
3
1
3
3
(
=CCl), 131.50 (=CHCl), 26.71 (CH ). Found, %:
3
C 35.03; H 3.14; Cl 51.44. C H Cl O. Calculated, %:
C 34.57; H 2.90; Cl 51.02.
4
4
2
Propyl 1,2-dichlorovinyl ketone (III) was obtained
–
1
1
Compound VI. IR spectrum, n, cm : 1720 (C=O). H
NMR spectrum (CDCl ), d, ppm: 6.08 d (1H, CHCl ,
in a similar way from 53.28 g (0.5 mol) of butyryl chloride,
6
mol) of dichloroethylene. Yield 62.6 g (75%), bp 68–70°C
6.67 g (0.5 mol) of aluminum chloride, and 100 g (1
3
2
J 6.84 Hz ), 4.57 d (1H, CHCl2, J 6.84 Hz), 2.74 t (2H,
2
0
–1
CH , J 7.27 Hz), 1.69 m (2H, CH ), 0.94 t (3H, CH ,
(
(
9 mm Hg), nD 1.4900. IR spectrum, n, cm : 1570
C=C), 1695 (C=O), 3080 (=C–H). H (CDCl ), d, ppm:
2
2
3
1
J 7.33 Hz).
3
7
.54 s (1H, =CH), 2.74 t (2H, CH , J 7.20 Hz), 1.66 m
2
1,2-Dichlorovinyl methyl ketone 2,4-dinitrophen-
ylhydrazone (VII). To a solution of 1.98 g (0.01 mol) of
,4-dinitrophenylhydrazine in 50 ml of anhydrous methanol
1
3
(
2H, CH ), 0.953 t (3H, CH , J 7.2 Hz). C, d, ppm:
2 3
92.43 (C=O), 134.83 (=CCl), 130.64 (=CHCl), 40.73
1
2
(
CH ), 17.15 (CH ), 13.35 (CH ). Found, %: C 43.15;
2 2 3
and 0.5 ml of concn. H SO was added at stirring 1.37 g
2
4
H 4.85; Cl 42.49. C H Cl O. Calculated, %: C 43.14;
H 4.83; Cl 42.45.
6
8
2
(0.01 mol) of ketone I. After the heat evolution ended
the solution was stirred for 15 min at 60°C. The separated
precipitate was filtered off and dried. Yield 2.30 g (98%),
Synthesis of methyl 1,2,2-trichloroethyl ketone
IV) and methyl 1,2-dichlorovinyl ketone (I)
–
1
(
mp 205–206°C. IR spectrum, n, cm : 1300, 1330, 1430,
RUSSIAN JOURNALOF ORGANIC CHEMISTRY Vol. 40 No. 11 2004

1590
BOZHENKOV et al.
1
500, 1580 (NO ), 1600 (C=N), 3080 (=C–H), 3320
%: C 53.10; H 7.51; Cl 22.30; N 17.89. C H ClN .
7 11 2
Calculated, %: C 53.00; H 6.99; Cl 22.35; N 17.66.
2
1
(
NH). H NMR spectrum [(CD ) CO], d, ppm: 11.18 s
3
2
3
4
5
(
1H, NH), 9.02 d (1H, H , J 2.6 Hz), 8.48 d.d (1H, H ,
J 9.5, J 2.6 Hz), 8.13 d (1H, H , J 9.5 Hz), 7.53 s (1H,
CH), 2.41 c (3H, CH ). Found, %: C 38.05; H 2.80; Cl
(
b) To a solution of 0.6 g (0.01 mol) of ethylhydr-
3
4
6 3
azine and 1.01 g (0.01 mol) of triethylamine in 15 ml
of anhydrous ethanol was added dropwise at stir-
ring a solution of 1.53 g (0.01 mol) of ethyl 1,2-di-
chlorovinyl ketone in 5 ml of anhydrous ethanol,
and the mixture was stirred for 2 h. From filtrate
by distilling off the solvents 1.34 g (80%) of pyrazole
XI was isolated.
=
3
2
2.58; N 18.55. C H Cl N O . Calculated, %: C 37.64;
10 8 2 4 4
H 2.53; Cl 22.22; N 17.56.
,2-Dichlorovinyl ethyl ketone 2,4-dinitrophenyl-
hydrazone (VIII) was obtained similarly from 0.4 g
2 mmol) of 2,4-dinitrophenylhydrazine in a mixture
of 2 ml H SO and 10 ml of ethanol and from 0.31 g
1
(
2
4
1-Heptyl-3-methyl-4-chloropyrazole (X) was
prepared similarly from 1.3 g (0.01 mol) of
heptylhydrazine, 1.01 g (0.01 mol) of triethylamine, and
1.39 g (0.01 mol) of 1,2-dichlorovinyl methyl ketone.Yield
1.83 g (85%), viscous fluid, purified by column
(
(
2 mmol) of 1,2-dichlorovinyl ethyl ketone. Yield 0.6 g
98%), mp 204°C. IR spectrum, n, cm : 1300, 1330,
–
1
1
1
575 (NO ), 1490 (C=C), 1620 (C=N), 3300 (NH). H
2
NMR spectrum (DMSO-d ), d, ppm: 11.15 s (1H, NH),
6
3
4
5
3
4
8
2
2
.92 d (1H, H , J 2.6 Hz), 8.43 d.d (1H, H , J 9.5, J
.6 Hz), 8.02 d (1H, H , J 9.5 Hz), 7.68 s (1H, =CH),
.78 q (2H, CH , J 7.6 Hz), 1.20 t (3H, CH , J 7.6 Hz).
20
chromatography on silica gel, eluent hexane, nD 1.4800.
6
3
–1
IR spectrum, n, cm : 1540 (C=C), 2860, 2930, 2960
1
2
3
(Alk), 3140 (=C–H). H NMR spectrum (CDCl ), d,
3
Found, %: C 39.97; H 3.41; Cl 20.28; N 18.63.
C H Cl N O . Calculated, %: C 39.66; H 3.03; Cl 21.28;
N 16.82.
ppm: 7.26 s (1H, =C–H), 3.96 t (2H, CH , J 7.1 Hz),
2
11
10
2
4
4
1.78 m (2H, CH ), 1.26 m [8H, (CH ) ], 0.86 t (3H, CH ,
2
2 4
3
J 7.1 Hz). 13C NMR spectrum, d, ppm: 144.8 (C ), 126.7
(C5), 108.0 (C4), 52.3, 31.4, 30.0, 28.5, 26.2, 23.3, 13.7
3
1,2-Dichlorovinyl propyl ketone 2,4-dinitrophen-
ylhydrazone (IX) was obtained from 0.49 g (2.5 mmol)
of 2,4-dinitrophenylhydrazine and 4.17 g (2.5 mmol) of
(
C H ). Found, %: C 60.78; H 8.91; Cl 16.54; N 12.59.
7 15
C H ClN . Calculated, %: C 61.53; H 8.92; Cl 16.51;
N 13.05.
1
1
19
2
1
1
,2-dichlorovinyl propyl ketone in 2 ml of H SO and
2 4
0 ml of methanol. Yield 8.60 g (98%), mp 75°C. IR
1
-Benzyl-3-ethyl-4-chloropyrazole (XII) was
–
1
spectrum, n, cm : 1300, 1330, 1575 (NO ), 1490 (C=C),
1
d, ppm: 11.42 s (1H, NH), 9.13 d (1H, H , J 2.6 Hz),
2
prepared similarly from 1.22 g (0.01 mol) of
benzylhydrazine, 1.01 g (0.01 mol) of triethylamine, and
1
1
620 (C=N), 3300 (NH). H NMR spectrum (CDCl ),
3
3
4
.53 g (0.01 mol) of 1,2-dichlorovinyl ethyl ketone. Yield
.98 g (90%), viscous fluid, purified by column
5
3
4
6
8
.39 d.d (1H, H , J 9.5, J 2.6 Hz), 8.06 d (1H, H ,
1
3
J 9.5 Hz), 7.01 s (1H, =CH), 2.64 t (2H, CH , J
2
2
0
chromatography on silica gel, eluent hexane, n 1.5610.
IR spectrum, n, cm : 1520 (C=C), 2870, 2940, 2970
(
ppm: 7.21 s (1H, =C–H), 7.32–7.20 m (5H, C H ), 5.17
s (2H, CH ), 2.68 q (2H, CH , J 7.6 Hz), 1.29 t (3H,
CH , J 7.6 Hz). Found, %: C 67.05; H 6.00; Cl 15.27;
N 12.08. C H ClN . Calculated, %: C 67.10; H 5.63;
D
1
2.9 Hz), 1.77 m (2H, CH ), 1.13 t (3H, CH , J 11.6 Hz).
2 3
–
1
Found, %: C 41.70; H 3.60; Cl 21.00; N 16.10.
C H Cl N O . Calculated, %: C 41.52; H 3.48; Cl 20.42;
1
Alk), 3140 (=C–H). H NMR spectrum (CDCl ), d,
3
12
12
2
4
4
6
5
N 16.14.
2
2
1,3-Diethyl-4-chloropyrazole (XI). (a) To a solution
3
of 1.2 g (0.02 mol) of ethylhydrazine in 15 ml of
anhydroushexane was added dropwise at stirring 1.53 g
1
2
13
2
Cl 15.23; N 12.04.
(
0.01 mol) of ethyl 1,2-dichlorovinyl ketone. After the
1
-Ethyl-3-propyl-4-chloropyrazole (XIII) was
end of heat evolution the reaction mixture was stirred
for 1–2 h. The precipitated ethylhydrazine hydrochloride
was filtered off and dried in a vacuum over P O . The
prepared in the same way from 0.6 g (0.01 mol) of
ethylhydrazine, 1.01 g (0.01 mol) of triethylamine, and
1.67 g (0.01 mol) of 1,2-dichlorovinyl propyl ketone.Yield
1.29 g (75%), bp 70°C (5 mm Hg), n 1.4838. IR
spectrum, n, cm : 1520 (C=C), 2860, 2940, 2960 (Alk),
2
5
distillation of filterate afforded 1.27 g (80%) of pyrazole,
–
1
20
bp 77–80°C (14–15 mm Hg). IR spectrum, n, cm : 1560
D
1
–1
(
C=C), 2860, 2940, 2960 (Alk), 3130 (=C–H). H NMR
1
spectrum (CDCl ), d, ppm: 7.27 s (1H, =C–H), 4.03 q
3140 (=C–H). H NMR spectrum (CDCl ), d, ppm:
3
3
(
2H, CH , J 7.3 Hz), 2.61 q (2H, CH , J 7.7 Hz), 1.41 t
7.27 s (1H, =C–H), 4.03 q (2H, CH , J 7.3 Hz), 2.56 t
2
2
2
(
3H, CH , J 7.3 Hz), 1.23 t (3H, CH , J 7.7 Hz). Found,
(2H, CH , J 7.5 Hz), 1.66 m (2H, CH ), 1.40 t (3H, CH ,
3
3
2
2
3
RUSSIAN JOURNALOF ORGANIC CHEMISTRY Vol. 40 No. 11 2004

SYNTHESIS, STRUCTURE, AND CHARACTERISTICS OF 1,2-DICHLOROVINYL ALKYLKETONES
1591
1
3
J 7.3 Hz), 0.94 t (3H, CH , J 7.5 Hz). C NMR spectrum,
2002, no. 22.
3
3
5
4
d, ppm: 148.8 (C ), 126.1 (C ), 107.7 (C ), 27.5, 15.1,
3.5 (C H ). Found, %: C 55.60; H 7.45; Cl 20.58;
N 16.31. C H ClN . Calculated, %: C 55.65; H 7.59;
3. Prins, H.J. and Haring, H.G., Rec. Trav. Shim., 1954,
vol. 73, p. 479; Chem. Abstr., 1955, 12265b.
4. Lichty, J.G., US Patent 2415796; Chem. Abstr.,1947, vol. 41,
P3127.
1
3
7
8
13
2
Cl 20.53; N 16.22.
5
. Tolstikov, G.A., Ismailov, S.A., Prishchepova, E.V., and
Miftakhov, M.S., Zh. Org. Khim., 1991, vol. 27, p. 2334.
. Joriczyk,A. and Gierczak,A., Synthesis, 1998, p. 962.
.Atavin,A.S., Mirskova,A.N., and Levkovskaya, G.G., Zh.
Org. Khim., 1973, vol. 9, p. 318.
The reactions of alkylhydrazines with 1,2-dichlorovinyl
ketones at the reagents ratio 1:1 (in the presence of
triethylamine) and 2:1 in ether, hexane, benzene, lower
alcohols (methanol, ethanol, 2-propanol) under similar
conditions also gave rise to pyrazoles X–XIII in 60–
6
7
8
. Levkovskaya, G.G., Mirskova,A.N., and Voronkov, M.G.,
Izv. Akad. Nauk SSSR, Ser.Khim., 1977, vol. 9, p. 1816.
. Levkovskaya, G.G., Bozhenkov, G.V., Larina, L.I., Evstaf’e-
va, I.T., and Mirskova, A.N., Zh. Org. Khim., 2001,
vol. 37, p. 684.
80% yield.
Reaction of 1,2-dichlorovinyl ethyl ketone with
9
1,1-dimethylhydrazine. To a solution of 1.67 g (0.01
mol) of 1,2-dichlorohex-1-en-3-one in anhydrous ether
cooled to –78°C was slowly added 1.20 g (0.02 mol) of
1
0. Bozhenkov, G.V., Levkovskaya, G.G., and Mirskova,A.N.,
Zh. Org. Khim., 2002, vol. 38, p. 140; Bozhenkov, G.V.,
Frolov, Yu.L., Toryashinova, D.S-D., Levkovskaya, G.G.,
and Mirskova, A.N., Zh. Org. Khim., 2003, vol. 39,
p. 857.
1
,1-dimethylhydrazine. After the end of heat evolution
the precipitate of dimethylhydrazinium hydrochloride was
filtered off and dried in a vacuum over P O . Yield of the
2
5
salt 0.86 g (89%), mp 60°C (publ.: mp 81–82°C [18]). IR
–
1
spectrum, n, cm : 1470, 1620, 2520, 2700, 2950, 3000,
1
1. Levkovskaya, G.G., Mirskova,A.N., Bryukhova, E.V., Kaza-
1
3
2
130, 3250. H NMR spectrum (CD OD), d, ppm:
3
kov, V.P., and Atavin, A.S., Izv. Akad. Nauk SSSR, Ser.
Khim., 1975, vol. 4, p. 793; Gavrilova, G.A., Keiko, V.V.,
Levkov-skaya, G.G., Mirskova,A.N., and Frolov, Yu.L., Izv.
Akad. Nauk SSSR, Ser. Khim., 1978, p. 84.
.96 s. Found, %: C 23.58; H 10.24; Cl 35.97; N 29.37.
C H ClN . Calculated, %: C 24.99; H 9.44; Cl 36.41;
2
9
2
N 29.16.
After the solvent was distilled off from the filtrate the
oily substance that fast darkened was passed through a
1
2. Shainyan, B.A., Levkovskaya, G.G., and Mirskova, A.N.,
Izv. Akad. Nauk SSSR, Ser. Khim., 1978, p. 934.
column (eluent CHCl ), the solvent was removed, the
3
13. Frisch, M.J., Trucks, G.W., Schlegel, H.B., Scuseria, G.E.,
Robb, M.A., Cheeseman, J.R., Zakrzewski, V.G.,
Montgomery, Jr. J.A., Stratmann, R.E., Burant, J.C.,
Dapprich, S., Millam, J.M., Daniels, A.D., Kudin, K.N.,
Strain, M.C., Farkas, O., Tomasi, J., Barone, V., Cossi, M.,
Cammi, R., Mennucci, B., Pomelli, C., Adamo, C., Clif-
ford, S., Ochterski, J., Petersson, G.A., Ayala, P.Y., Cui, Q.,
Morokuma, K., Malick, D.K., Rabuck, A.D., Raghava-
chari, K., Foresman, J.B., Cioslowski, J., Ortiz, J.V., Ste-
fanov, B.B., Liu, G., Liashenko, A., Piskorz, P., Koma-
romi, I., Gomperts, R., Martin, R.L., Fox, D.J., Keith, T.,Al-
Laham, M.A., Peng, C.Y., Nanayakkara, A., Gon-
zalez, C., Challacombe, M., Gill, P.M.W., Johnson, B.,
Chen, W., Wong, M.W., Andres, J.L., Gonzalez, C.,
Head-Gordon, M., Replogle, E.S., and Pople, J.A., Gaussian
98, RevisionA.6, Pittsburgh: Gaussian, Inc., 1998.
–
1
residue was dried in a vacuum. IR spectrum, n, cm :
1
460, 1570, 1600, 1640, 1650, 2860, 2960, 3000, 3130.
1
H NMR spectrum (CDCl ), d, ppm: 0.87 t, 2.57 m, 3.01
3
m, 7.26 s. A large number of weak signals was observed
in the regions 2.13–3.12, 3.5–3.9, 7.47–8.12 ppm
The authors are grateful to Professor V.A.Lopyrev
for the help in performing calculations and to Candidate
of the Chemical Sciences T.I. Aksamentova for
measuring the dipole moments.
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2
. Kochetkov, N.K., Usp. Khim., 1955, vol. 24, p. 32; Poh-
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