Reaction of 2,4-dinitrophenylhydrazones of triphenyl(2-aroylethyl) phosphonium bromides with aqueous alkali and some transformations of the betaines formed

Article abstract of DOI:10.1134/S1070363209010137

Triphenyl(2-p-toluoylethyl)- and triphenyl(2-p-bromobenzoylethyl) phosphonium bromide 2,4-dinitrophenylhydrazones were established to form a bipolar compounds with a negatively charged nitrogen atom and a positively charged phosphonium atom, under the act

Full text of DOI:10.1134/S1070363209010137

ISSN 1070-3632, Russian Journal of General Chemistry, 2009, Vol. 79, No. 1, pp. 88–91. © Pleiades Publishing, Ltd., 2009.
Original Russian Text © R.Dzh. Khachikyan, 2009, published in Zhurnal Obshchei Khimii, 2009, Vol. 79, No. 1, pp. 90–93.
Reaction of 2,4-Dinitrophenylhydrazones
of Triphenyl(2-aroylethyl)phosphonium Bromides
with Aqueous Alkali and Some Transformations
of the Betaines Formed
R. Dzh. Khachikyan
Institute of Organic Chemistry, National Academy of Sciences of Armenia,
ul. Zakariya Kanakertsy 167-A, Erevan, 375091 Armenia
fax: (374+1)283511
e-mail: nara7777@mail.ru
Received April 24, 2008
Abstract―Triphenyl(2-p-toluoylethyl)- and triphenyl(2-p-bromobenzoylethyl)phosphonium bromide 2,4-dinitro-
phenylhydrazones were established to form a bipolar compounds with a negatively charged nitrogen atom and a
positively charged phosphonium atom, under the action of aqueous alkali at 0°С. When refluxed in acetonitrile,
the product formed from triphenyl(2-p-toluoylethyl)phosphonium bromide undergoes cleavage by a five-
membered ring mechanism to give triphenylphosphine and tolyl vinyl ketone 2,4-dinitrophenylhydrazone. The
reactions of the above betains with methyl iodide give rise to N-alkylation and cleavage products, but, in
addition, iodide analogs of the starting phosphonium salt 2,4-dinitrophenylhydrazones which are probably
formed via N→С negative charge transfer, С-methylation, and reaction of the resulting products with N-
betaines.
DOI: 10.1134/S1070363209010137
Previously we found that triphenyl(2-aroylethyl)
phosphonium salt oximes, unlike their aroylmethyl
analogs, do not undergo cyclization under the action of
proton acceptors. Attempted heterocyclization of
hydrazones and phenylhydrazones of the mentioned
salts failed [1, 2].
However, the reactions of salts Iа and Ib with
aqueous alkali gave, instead of heterocycles, bipolar
compounds IIа and IIb having the negative charge on
nitrogen and the positive charge on phosphorus.
By heating betaines IIа and IIb with methyl iodide
in acetonitrile solution we obtained, along with N-
alkylation products IIIа and IIIb, compounds IVа and
IVb, which are analogs of the starting salts, as well as
methyltriphenylphosphonium iodide (V).
Proceeding with these studies we turned to
reactions of 2,4-dinitrophenylhydrazones (2,4-DNPH)
of (2-p-toluoylethyl)- and (2-p-bromobenzoylethyl)
triphenylphosphonium bromides (compounds Ia and
Ib, respectively) with aqueous alkali. It was expected
that the presence of strong electronegative substituents
in the phenylhydrazone group would make hetero-
cyclization possible.
Heating compound IIa in acetonitrile in the absence
of methyl iodide resulted in cleavage products, viz.
triphenylphosphine and tolyl vinyl ketone 2,4-
dinitrophenylhydrazone, probably formed by a five-
membered ring mechanism (Scheme 1).
_
OH
+
_
Br _
+
_
Ar_C_CH2 CH2 P(C6H5)3
_
_
Ar_C_CH2 CH2 P(C6H5)3,
Compounds IVа and IVb are hardly formed in no
other way that that involving N→С negative charge
transfer, С-methylation, and reaction of the resulting
products with N-betaines IIа and IIb (Scheme 2).
_
N_NH_C6H3(NO2)2
N_N_C6H3(NO2)2
Ia, Ib
IIa, IIb
The proposed scheme is consistent with the data of
Bestmann and Schulz [3, 4] on the formation of
Ia, IIa: Ar = CH3C6H4; Ib, IIb: Ar = BrC6H4.
88

REACTION OF 2,4-DINITROPHENYLHYDRAZONES
89
Scheme 1.
+
+
(C6H5)3P+_CH3
I_
_
_
Ar_C_CH2 CH2 P(C6H5)3
_
_
Ar_C_CH2 CH2 P(C6H5)3
IIа, IIb + CH3I
+
+
I_
I_
N_NH_C6H3(NO2)2
N_N_C6H3(NO2)2
CH3
IVa, IVb
V
IIIa, IIIb
IIIа, IVа: Ar = CH3C6H4; IIIb, IVb: Ar = BrC6H4.
to
+
CH3C6H4 C_CH=CH2
N_NH_C6H3(NO2)2
_
_
_
CH3C6H4 C_CH2 CH_P(C6H5)3
+
(C6H5)3P
H
_
N_N_C6H3(NO2)2
VIa
IIа
Scheme 2.
_
+
+
Ar_C_CH2 CH_P(C6H5)3
_
Ar_C_CH2 CH2 P(C6H5)3
_
_
_
N_NH_C6H3(NO2)2
N_N_C6H3(NO2)2
IIа, IIb
H3C
CH3
CH3I
+
IIа, IIb
+
I_
+
_
Ar_C_CH2 CH2 P(C6H5)3
_
_
Ar_C_CH C_P(C H )
6 5 3
Ar_C_CH2 CH_P(C6H5)3
+
_
_
2
I_
N_NH_C6H3(NO2)2
N_NH_C6H3(NO2)2
N_NH_C6H3(NO2)2
IVа, IVb
Scheme 3.
+
(C6H5)3P_CH_COOCH3
(C6H5)3P =CH_COOCH3 + RX
X _
R
A
_
A
+
+
(C6H5)3P_C_COOCH3
(C6H5)3P__CH2 COOCH3,
_
+
X
R
R = alkyl, allyl, benzyl.
alkylated ylides in reactiona of ylides A with alkyl,
allyl, and benzyl halides (Scheme 3).
was refluxed on a water bath for 30 h, and the
precipitate that formed was filtered off, washed with
alcohol, and dried in a vacuum. Yield 4.81 g (72%),
1
EXPERIMENTAL
mp 225–226°С. Н NMR spectrum (DMSO-d6), δ,
ppm: 2.40 s (3Н, СН3), 3.20 br. m (2Н, СH2СH2Р+),
4.02 br.m (2Н, СH2СH2Р+), 7.20 d (2Н, С6Н4, J 8.6 Hz),
7.50 d (2Н, С6H4, J 8.6 Hz), 7.75–8.00 br. m (15Н,
3С6Н5), 8.10 d (1Н, 2,4-DNPH о-Н, J 9.6 Hz), 8.40 d.
d (1Н, 2,4-DNPH m-Н, J 9.6 and 2.5 Hz), 8.96 d (1Н,
2,4-DNPH m-Н, J 2.5 Hz), 11.15 s (1Н, NH). 31Р
NMR spectrum, δ, ppm: 29.97. Found, %: С 61.0; Н
4.52; Br 12.0; N 8.27; P 4.72. С34Н30BrN4О4P. Cal-
culated, %: С 60.99; Н 4.48; Br 11.96; N 8.37; P 4.63.
1
The Н and 31Р NMR spectra were registered on a
Varian MERCURY-300 instrument (300 МHz) against
internal TMS.
Triphenyl(2-p-toluoylethyl)phosphonium bromide
2,4-dinitrophenylhydrazone (Iа). To an alcohol
solution of 1.98 g of 2,4-dinitrophenylhydrazine we
added 0.54 ml of 93% H2SO4 and 4.89 g of triphenyl
(2-p-toluoylethyl)phosphonium bromide. The mixture
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 79 No. 1 2009

90
KHACHIKYAN
СH2СH2Р+), 4.02 br. m (2Н, СH2СH2Р+), 7.20 d (2Н,
С6Н4, J 8.6 Hz), 7.50 d (2Н, С6H4, J 8.6 Hz), 7.70–8.00
br.m (15Н, 3С6Н5), 8.10 d (1Н, 2,4-DNPH о-Н, J
9.6 Hz), 8.40 d.d (1Н, 2,4-DNPH m-Н, J 9.6 and 2.5 Hz),
8.96 s (1Н, 2,4-DNPH m-Н, J 2.5 Hz), 11.15 s (1Н,
NH). The 31Р NMR spectrum, δ, ppm: 29.87. Found,
%: С 57.11; Н 4.19; I 17.85; N 7.98; P 4.21. С34Н30I·
N4О4P. Calculated, %: С 56.98; Н 4.25; I 17.74; N
7.82; P 4.33.
(2-p-Bromobenzoylethyl)triphenylphosphonium
bromide 2,4-dinitrophenylhydrazone (Ib) was
prepared similarly to compound Ia from 1.98 g of 2,4-
dinitrophenylhydrazine, 0.54 ml of 93% H2SO4 and
5.54 g of (2-p-bromobenzoylethyl)triphenylphospho-
nium bromide. Yield 5.51 g (75%), mp 254–255°С. 1Н
NMR spectrum (DMSO-d6), δ, ppm: 3.29 br. m (2Н,
СH2СH2Р+), 3.89 br. m (2Н, СH2СH2Р+), 7.58 d (2Н,
С6Н4, J 8.8 Hz), 7.62 d (2Н, С6Н4, J 8.8 Hz), 7.75–7.97
m (15Н, 3С6Н5), 8.06 d (1Н, 2,4-DNPH о-Н, J 9.6 Hz),
8.45 d. d (1Н, 2,4-DNPH m-Н, J 9.6 and 2.5 Hz), 8.92
d (1Н, 2,4-DNPH m-Н, J 2.5 Hz), 11.06 s (1Н, NH).
31Р NMR spectrum, δ, ppm: 29.71. Found, %: С 54.10;
Н 3.57; Br 21.97; N 7.75; P 4.01. С33Н27Br2N4О4P.
Calculated, %: С 53.95; Н 3.68; Br 21.80; N 7.63; P
4.22.
The acetonitrile filtrate was diluted with ether. The
precipitate that formed was filtered off and dried under
a vacuum to obtain 0.21 g of a mixture of salts IIIа
and V in yields of 0.17 g (48.0%) and 0.04 g (20%),
1
respectively (by Н and 31Р NMR data). Compound
1
IIIa. Н NMR spectrum (DMSO-d6), δ, ppm: 2.40 s
(3Н, СН3), 3.15 s (3Н, N–СH3), 3.29 br.m (2Н,
СH2СH2Р+), 3.65 br.m (2Н, СH2СH2Р+), 7.25 d (2Н,
С6Н4, J 8.6 Hz), 7.44 d (1Н, 2,4-DNPH о-Н, J 9.6 Hz),
7.57 d (2Н, С6H4, J 8.6 Hz), 7.65-7.95 br.m (15Н,
3С6Н5), 8.32 d.d (1Н, 2,4-DNPH m-Н, J 9.6 and
2.5 Hz), 8.45 d (1Н, 2,4-DNPH m-Н, J 2.5 Hz). 31Р
NMR spectrum, δ, ppm: 30.70.
Reactions of compounds Iа and Ib with aqueous
potassium hydroxide. To a saturated alcohol solution
of 0.67 g of compound Iа we added dropwise 1 ml of
1 N aqueous KOH under stirring in the cold. The
precipitate that formed was filtered off, washed with
water to pH 7, and dried under a vacuum to obtain
1
0.58 g (98.6%) of compound IIa, mp 165–166°С. Н
Compound IVb was prepared similarly from 0.46 g
of compound IIb and 1 ml of methyl iodide. Yield
NMR spectrum (DMSO-d6), δ, ppm: 2.34 s (3Н, СН3),
3.05 br.m (2Н, СH2СH2Р+), 3.99 br.m (2Н,
СH2СH2Р+), 7.06 d (2Н, С6Н4, J 8.6 Hz), 7.44 d (2Н,
С6H4, J 8.6 Hz), 7.55 br. d (2Н, 2,4-DNPH о- and m-
Н), 8.52 d (1Н, 2,4-DNPH m-Н, J 2.5 Hz). 31Р NMR
spectrum, δ, ppm: 29.79. Found, %: С 69.27; Н 5.12;
N 10.12; P 5.37. С34Н29N4О4P. Calculated, %: С
69.39; Н 4.93; N 9.52; P 5.27.
1
0.08 g (16%), mp 254–255°С. Н NMR spectrum
(DMSO-d6), δ, ppm: 3.29 br. m (2Н, СH2СH2Р+), 3.89
br. m (2Н, СH2СH2Р+), 7.57 d (2Н, С6Н4, J 8.8 Hz),
7.62 d (2Н, С6Н4, J 8.8 Hz), 7.75–7.98 m (15Н,
3С6Н5), 8.06 d (1Н, 2,4-DNPH о-Н, J 9.6 Hz), 8.45 d.
d (1Н, 2,4-DNPH m-Н, J 9.6 and 2.5 Hz), 8.92 d (1Н,
2,4-DNPH m-Н, J 2.5 Hz), 11.06 s (1Н, NН). 31Р
NMR spectrum, δ, ppm: 29.62. Found, %: С 50.32; Н
Compound IIb was prepared in a similar way from
0.73 g of compound Ib and 1 ml of 1N aqueous KOH.
3.85; Br 10.88;
I
16.95;
N
7.59;
P
4.18.
1
Yield 0.68 g (89%), mp 171–172°С. Н NMR spec-
С33Н27BrIN4О4P. Calculated, %: С 50.70; Н 3.46; Br
10.24; I 16.26; N 7.17; P 3.97.
trum (DMSO-d6), δ, ppm: 3.05 br. m (2Н, СH2СH2Р+),
4.00 br. m (2Н, СH2СH2Р+), 7.38 d (2Н, С6Н4, J
8.8 Hz), 7.45 d (2Н, С6H4, J 8.8 Hz), 7.58 br. d (2Н,
2,4-DNPH о- and m-Н), 7.70–7.88 m (15Н, 3С6Н5),
8.50 d (1Н, 2,4-DNPH m-Н, J 2.5 Hz). 31Р NMR
spectrum, δ, ppm: 29.75. Found, %: С 60.81; Н 4.09;
Br 12.10; N 8.71; P 4.37. С33Н26BrN4О4P. Calculated,
%: С 60.64; Н 3.98; Br 12.25; N 8.58; P 4.75.
From the acetonitrile filtrate we obtained 0.26 g of
a mixture of salts IIIb and V in yields of 0.13 g
(23,0%) and 0.13 g (46%), respectively (by 1Н and 31Р
NMR data). Compound IIIb. 1Н NMR spectrum
(DMSO-d6), δ, ppm: 3.16 s (3Н, N-CH3), 3.35 br. m
(2Н, СH2СH2Р+), 3.67 br.m (2Н, СH2СH2Р+), 7.46 d
(1Н, 2,4-DNPH о-Н, J 9.6 Hz), 7.70–7.88 br. m (19Н,
С6Н4, 3С6Н5), 8.34 d.d (1Н, 2,4-DNPH m-Н, J 9.6 and
2.5 Hz), 8.45 d (1Н, 2,4-DNPH m-Н, J 2.5 Hz). 31Р
NMR spectrum, δ, ppm: 30.85.
Reactions of compounds IIа and IIb with methyl
iodide. To a saturated acetonitrile solution of 0.3 g of
compound IIа we added 1 ml of methyl iodide. The
mixture was refluxed for 5 h. The precipitate that
formed was filtered off, washed with acetonitrile, and
dried under a vacuum to obtain 0.07 g (19.6%) of
p-Tolyl vinyl ketone 2,4-dinitrophenylhydrazone
(VIа). An acetonitrile solution of 0.2 g of compound
IIа was refluxed for 5 h. The precipitate that formed
was filtered off, washed with acetonitrile, and dried
1
compound IVa, mp 244–245°С. Н NMR spectrum
(DMSO-d6), δ, ppm: 2.40 s (3Н, СН3), 3.20 br. m (2Н,
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 79 No. 1 2009

REACTION OF 2,4-DINITROPHENYLHYDRAZONES
91
under a vacuum to obtain 0.08 g (80.0%) of compound
VIa, mp 220–221°С. Н NMR spectrum (DMSO-d6),
Its mixed sample with an authentic sample gave no
melting point depression.
1
δ, ppm: 2.42 s (3Н, CH3), 5.84 d. d (1Н, =СH2, J 9.0
and 4.6 Hz), 6.19 d. d (1Н, =СH2, J 6.2 and 4.6 Hz),
6.79 d. d (1Н, CH=, J 9.6 and 6.1 Hz), 7.22 d (2Н,
С6Н4, J 8.0 Hz), 7.65 d (2Н, С6Н4, J 8.0 Hz), 8.11 d
(1Н, 2,4-DNPH о-Н, J 9.6 Hz), 8.35 d.d (1Н, 2,4-
DNPH m-Н, J 9.6 and 2.5 Hz), 8.98 d (1Н, 2,4-DNPH
m-Н, J 2.5 Hz), 11.54 s (1Н, NH).
REFERENCES
1. Khachikyan, R.Dzh., Zh. Obshch. Khim., 2007, vol. 77,
no. 12, p. 1048.
2. Khachatryan, R.А., Khachikyan, R.Dzh., Zalinyan, S.A.,
Gevorgyan, G.A., Karamyan, N.V., and Indzhikyan, M.G.,
Khim. Zh. Armenii, 2001, vol. 54, nos. 3–4, p. 61.
3. Bestmann, H. J. and Schulz, H., Tetrahedron Lett.,
Triphenylphosphine (0.67 g, 75%) obtained from
the acetonitrile filtrate was identified as iodomethylate.
1960, no. 4. p. 5.
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 79 No. 1 2009