Structure of the products of acrolein reactions with pyrazoles

Full text of DOI:10.1134/S1070428006120220

ISSN 1070-4280, Russian Journal of Organic Chemistry, 2006, Vol. 42, No. 12, pp. 1868–1870. © Pleiades Publishing, Inc., 2006.
Original Russian Text © O.S. Attaryan, S.K. Antanosyan, F.S. Kinoyan, R.A. Tamazyan, G.A. Panosyan, S.G. Matsoyan, 2006, published in Zhurnal
Organicheskoi Khimii, 2006, Vol. 42, No. 12, pp. 1875–1877.
SHORT
COMMUNICATIONS
Structure of the Products of Acrolein Reactions with Pyrazoles
a
a
a
b
O. S. Attaryan , S. K. Antanosyan , F. S. Kinoyan , R. A. Tamazyan ,
b
a
G. A. Panosyan , and S. G. Matsoyan
a
Institute of Organic Chemistry, National Academy of Sciences of Armenia,
ul. Zakariya Kanakertsi 167a, Erevan, 375091 Armenia
e-mail: org.chemistry@netsys.am
b
Molecular Structure Research Center, National Academy of Sciences of Armenia, Erevan, Armenia
Received August 17, 2005
DOI: 10.1134/S1070428006120220
Pyrazoles I–IV reacted with acrolein to give 3-(1H-
pyrazol-1-yl)propionaldehydes V–VIII in fairly high
yields (Scheme 1).
a product of condensation of two molecules of pyra-
zolylaldehyde VI with one water molecule. Molecule
IX may be regarded as consisting of two 3-(3,5-di-
methyl-1H-pyrazol-1-yl)propionaldehyde moieties
1
Scheme 1.
linked through the O atom (Fig. 1); the hydroxy
3
3
14
14
R'
R
R'
R
groups of each part (O –H and O –H ) are involved
in intramolecular hydrogen bonds with the pyridine-
like nitrogen atom in the pyrazole ring of the other part
CH =CHCHO
2
N
N
R
R
N
H
N
18
7
(
N and N , respectively). The molecule is symmetric
CH CH CHO
2
2
through a second-order symmetry axis which is not
a crystallographic symmetry element (Fig. 1). Presum-
ably, the intramolecular hydrogen bonds make the
molecule conformationally more rigid. Molecules IX
in crystal are packed together with water molecules
I–IV
V–VIII
I, V, R = R' = H; II, VI, R = Me, R' = H; III, VII, R = Me,
R' = Cl; IV, VIII, R = Me, R' = Br.
2
4
The structure of compounds V–VIII was confirmed
(O ) at a ratio of 2:1. The hydrogen atoms in H O
2
1
14
by the analytical and H NMR data. Surprisingly,
form two intermolecular hydrogen bonds with the O
liquid compound VI on storage was transformed into
crystalline product IX (Scheme 2) whose H NMR
spectrum lacked aldehyde proton signal (δ 9.74 ppm in
atoms of two molecules IX (Fig. 2). Only one oxygen
1
14
atom (O ) in each molecule IX participates in hydro-
14
gen bonding with water molecule. Thus the O atom
the spectrum of VI), but a new signal appeared at
in IX is involved in intramolecular hydrogen bond
–
1
14
14
7
δ 4.80 ppm. Absorption bands at 2720 and 1715 cm ,
which are typical of aldehyde group, disappeared from
the IR spectrum, and new absorption bands assignable
to water molecules were observed at 3100–3500 and
O ··· H ···N and intermolecular hydrogen bond
2
4
24
14
3
O ···H ···O , while the other oxygen atom (O )
participates only in intramolecular hydrogen bonding
3
3
18
O ···H ···N . The bond lengths and bond angles in
structure IX are consistent with the corresponding
standard values.
–
1
1
640 cm (δHOH). The structure of compound IX
was unambiguously determined by X-ray analysis: it is
Scheme 2.
Me
Me
Me
H O
2
N
·
··H
H···
N
N
N
Me
O
O
N
N
Me
Me
CH CH CHO
2
2
O
VI
IX
1868

STRUCTURE OF THE PRODUCTS OF ACROLEIN REACTIONS WITH PYRAZOLES
1869
1
1
C
Compound IX decomposed on heating to give
4
3
C
initial pyrazolylaldehyde VI; treatment of the latter
with hydroxylamine afforded the corresponding oxime
X (Scheme 3).
O
5
C
10
2
C
C
3
2
3
H
C
6
9
N
C
1
Scheme 3.
18
O
7
1
9
N
N
8
C
C
Me
1
6
13
C
C
2
0
14
1
2
Δ
NH OH
C
2
17
H
14
C
N
IX
VI
N
C
15
Me
C
O
N
21
CH CH CH=NOH
2
2
2
2
X
C
Fig. 1. Structure of the molecule of 1,1'-oxybis[3-(3,5-di-
methyl-1H-pyrazol-1-yl)propan-1-ol] (IX) according to the
X-ray diffraction data. Hydrogen atoms are not shown. Intra-
molecular hydrogen bonds are shown with dashed lines.
It should be emphasized that the other pyrazolyl-
aldehydes, both unsubstituted V and 4-halo-3,5-di-
methylpyrazolyl derivatives VII and VIII, did not
change on storage. Therefore, we concluded that the
main factor responsible for the transformation of pyra-
zolylpropionaldehyde VI into compound IX is the
possibility for hydrogen bonding with more nucleo-
philic pyridine-like nitrogen atoms in the pyrazole ring
of VI (Fig. 1), as compared to V, VII, and VIII.
3-(4-Chloro-3,5-dimethyl-1H-pyrazol-1-yl)-
propionaldehyde (VII) was synthesized in a similar
way from 4-chloro-3,5-dimethyl-1H-pyrazole (III).
Yield 75%, bp 110°C (1 mm), crystallized on storage,
–
1
mp 98–99°C. IR spectrum, ν, cm : 1525 (ring), 1571
1
(
(
4
1
C=O). H NMR spectrum, δ, ppm: 2.10 s and 2.25 s
3H each, CH ), 2.95 t.d (2H, COCH , J = 6.4, 1.2 Hz),
Initial pyrazoles I–IV were synthesized according
to the procedures described in [1–3], and their physical
constants coincided with published data.
3
2
.1 t (2H, NCH , J = 6.4 Hz), 9.70 t (1H, CHO, J =
2
.1 Hz). Found, %: C 51.40; H 5.95; Cl 19.34;
3
-(1H-Pyrazol-1-yl)propionaldehyde (V). A solu-
N 14.98. C H ClN O. Calculated, %: C 51.49; H 5.90;
8
11
2
tion of 0.07 mol of acrolein in 20 ml of dioxane was
added to a solution of 0.05 mol of pyrazole I in 20 ml
of dioxane at such a rate that the temperature did not
exceed 40°C, and the mixture was then stirred for 24 h
at 40°C. The solvent was distilled off, and the residue
was distilled under reduced pressure. Yield 80%,
Cl 19.01; N 15.02.
3
-(4-Bromo-3,5-dimethyl-1H-pyrazol-1-yl)-
propionaldehyde (VIII) was synthesized in a similar
way from 4-bromo-3,5-dimethyl-1H-pyrazole (IV).
Yield 80%, bp 120°C (1 mm), crystallized on storage,
–1
mp 124–126°C. IR spectrum, ν, cm : 1530 (ring),
2
0
20
bp 85°C (1 mm), n = 1.4996, d = 1.1230. IR spec-
1
D
4
1
2
571 (C=O). H NMR spectrum, δ, ppm: 2.10 s and
.25 s (3H each, CH ), 2.95 t.d (2H, COCH , J = 6.4,
–1
1
trum, ν, cm : 1510 (ring), 1715 (C=O). H NMR spec-
trum, δ, ppm: 2.99 t.d (2H, COCH , J = 6.4, 1.2 Hz),
3
2
2
1.2 Hz), 4.1 t (2H, NCH , J = 6.4 Hz), 9.71 t (1H,
CHO, J = 1.1 Hz). Found, %: C 41.50; H 4.70;
Br 34.58; N 12.31. C H BrN O. Calculated, %:
C 41.56; H 4.76; Br 34.63; N 12.20.
2
4
2
5
.42 t (2H, NCH , J = 6.4 Hz), 6.13 d.d (1H, 4-H, J =
.3, 1.9 Hz), 7.32 d (1H, 3-H, J = 1.9 Hz), 7.53 d (1H,
-H, J = 2.3 Hz), 9.74 t (1H, CHO, J = 1.2 Hz). Found,
2
8
11
2
%
%
: C 58.12; H 6.38; N 22.65. C H N O. Calculated,
6 8 2
1
,1'-Oxybis[3-(3,5-dimethyl-1H-pyrazol-1-yl)-
: C 58.06; H 6.45; N 22.58.
-(3,5-Dimethyl-1H-pyrazol-1-yl)propionalde-
hyde (VI) was synthesized in a similar way from
,5-dimethyl-1H-pyrazole (II). Yield 85%, bp 95°C
propan-1-ol] (IX). Pyrazolylpropionaldehyde VI crys-
tallized on storage to give compound IX, mp 85–95°C.
3
–
1
IR spectrum, ν, cm : 1530 (ring); 3100–3500 (OH),
1
3
1640 (δOH). H NMR spectrum, δ, ppm: 1.91 t.d (4H,
2
0
–1
(
1 mm), n = 1.4988. IR spectrum, ν, cm : 1530
CH
CH
2
, J = 6.7, 5.6 Hz), 2.10 s and 2.24 s (6H each,
), 3.95–4.10 m (4H, NCH ), 4.80 t (2H, CH, J =
D
1
(
ring), 1715 (C=O). H NMR spectrum, δ, ppm: 2.10 s
3
2
5.6 Hz), 5.67 s (2H, 4-H), 6.19 br (2H, HOH). Found,
and 2.26 s (3H each, CH ), 2.96 t.d (2H, COCH , J =
3
2
%
: C 60.55; H 7.95; N 16.80. C H N O . Calculated,
6
.4, 1.1 Hz), 4.17 t (2H, NCH , J = 6.4 Hz), 5.65 s
16 24 4 3
2
%
: C 60.00; H 7.50; N 17.50.
3-(3,5-Dimethyl-1H-pyrazol-1-yl)propionalde-
hyde oxime (X). A mixture of 0.075 mol of hydroxyl-
(
1H, 4-H), 9.74 t (1H, CHO, J = 1.1 Hz). Found, %:
C 63.28; H 7.78; N 18.28. C H N O. Calculated, %:
8
12
2
C 63.16; H 7.89; N 18.42.
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 42 No. 12 2006

1
870
ATTARYAN et al.
2
4
O
2
4
H
1
4
1
4
24
O
O
H
Fig. 2. Formation of dimeric structures by molecules of 1,1'-oxybis[3-(3,5-dimethyl-1H-pyrazol-1-yl)propan-1-ol] (IX)
and water in crystal.
amine and 0.05 mol of compound IX in 30 ml of
ethanol was heated for 5 h under reflux. The solvent
was removed under reduced pressure, and the crystals
were filtered off and dried. Yield 90%, mp 85°C. IR
tallization from dioxane. Reflection intensities were
measured from a 0.25 × 0.3 × 0.35-mm crystal on
an Enraf–Nonius CAD-4 automatic diffractometer;
4354 independent reflections were measured. Mono-
clinic crystal system, space group C2/c; a = 27.851(6),
b = 7.927(2), c = 17.024(3) Å; β = 106.18(3)°. The
structure was solved by the direct method using
SHELXTL program. The coordinates of hydrogen
atoms were determined from the Fourier difference
syntheses of electron density. In the final step, the
coordinates of all atoms (including hydrogen atoms)
and anisotropic thermal parameters of non-hydrogen
atoms were refined by the full-matrix least-squares
procedure. The complete set of crystallographic data
for compound IX is available from the authors.
–
1
spectrum, ν, cm : 1530 (ring), 1640 (CH), 3100–3300
1
(
OH). H NMR spectrum, δ, ppm: syn isomer: 2.10 s
and 2.25 s (3H each, CH ), 2.70 t.d (2H, CH , J = 7.2,
3
2
5
.4 Hz), 4.06 t (2H, NCH , J = 7.2 Hz), 5.65 s (1H,
2
4-H), 7.25 t (1H, NCH, J = 5.4 Hz), 10.77 s (1H, OH);
anti isomer: 2.10 s (3H, CH ), 2.95 t.d (1H, CH ,
3
2
J = 7.2, 5.4 Hz), 4.05 t (2H, NCH , J = 7.2 Hz),
2
5
1
.65 s (1H, 4-H), 6.59 t (1H, NCH, J = 5.4 Hz),
0.32 s (1H, OH).
1
The H NMR spectra were recorded on a Varian
Mercury-300 spectrometer (300 MHz). The IR spectra
were obtained on a Specord 75IR spectrometer from
thin films. The products were analyzed by GLC on
an LKhM-8MD chromatograph [1.5-m×3-mm column
packed with 10% of Carbowax-20M on Inerton AW-
HMDS (0.20–0.25 mm); carrier gas helium, flow rate
REFERENCES
1
2
. Jones, R.G., J. Am. Chem. Soc., 1949, vol. 71, p. 3994.
. Organic Syntheses, Noland, W.E., Ed., New York: Wiley,
1
963, collect. vol. 4, p 351.
5
0 ml/min].
3
. Attaryan, O.S., Eliazyan, G.A., Asratyan, G.V., Pano-
syan, G.A., Darbinyan, E.G., and Matsoyan, S.G., Arm.
Khim. Zh., 1986, vol. 39, p. 511.
X-Ray diffraction study. Crystals of compound IX
suitable for X-ray analysis were obtained by slow crys-
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 42 No. 12 2006