‫المجلد السابع عشر‬-5002-‫المجلة القطرية للكيمياء‬
National Journal of Chemistry, 2005, Volume 17
Synthesis of New 5-Ethyl-5-Phenyl
Barbituric Acid Derivatives
Redha I. H. AL-Bayati
Department of Chemistry, College of Science, AL-Mustansiriya University
Baghdad, Iraq.
Raad M. Muslih and Nagham M. AL-Janabiy
Department of Chemistry, College of Science for girls, University of Baghdad
Baghdad, Iraq.
(NJC)
(Received on 16/ 10 /2004)
(Accepted for publication on 23/3/2005)
Abstract
The reaction of some new Schiff bases (5-ethyl-5-phenyl-1,3-di[N-4-substituted
benzilidin hydrazinyl] barbituric acids) with benzoyl chloride or 3,5-dinitrobenzoyl
chloride were carried out. Subsequent reactions of these products di[N-(chloro(substituted benzyl)-N-benzoyl or 3,5-dinitro benzoyl)-5-ethyl-5-phenyl-1,3-di(acetic
acid hydrazinyl) barbituric acids with thiourea afforded thioureas compounds.
The synthesized compounds were confirmed by their IR, UV spectra and C.H.N.
analyses data.
‫الخالصــة‬
‫تعطي تفاعالت قواعد شيف جديدة‬
(5-ethyl-5-phenyl-1,3-di[N-4-substituted benzilidin hydrazinyl]
barbituric acids)
‫ثنائي نتروالبنزويل مركبات‬-5,3 ‫مع كلوريد البنزويل أو كلوريد‬
di[N-(-chloro-substituted benzyl)-N-benzoyl or 3,5-dinitro benzoyl]
-5-ethyl-5-phenyl-1,3-di(acetic acid hydrazinyl) barbituric acids
.‫وتفاعالت المركبات الناتجة مع الثايويوريا يؤدي إلى تكوين مركبات الثايويوريز‬
.‫) والتحليل الدقيق للعناصر‬UV, IR( ‫شخصت المركبات المحضرة باستخدام بعض الطرق الطيفية‬
diverse pharmacological
properties
Introduction
Phenobarbital
interesting
series
derivatives
of
such as antifungal
are
antipulsive
heterocyclic
(4)
(2)
, antimicrobial
and antibacterial
(1)
(3)
,
(5,6)
. This
paper reports the synthesis of some new
compounds, which have been shown to be
122
National Journal of Chemistry, 2005, Volume 17
phenobarbital
the
mixture was refluxed for (6 hrs), cooled,
reaction of some phenobarbital system
filtered and recrystallized from suitable
containing Schiff bases moiety with
solvent (Tables 1,2,3,7).
benzoyl
compounds
and
from
‫المجلد السابع عشر‬-5002-‫المجلة القطرية للكيمياء‬
3,5-dinitro
benzoyl
chlorides. Subsequent reactions of these
Preparation
products with thiourea afforded thioureas
compounds (16-25) (9): -
compounds.
of
isothioureas
To an appropriate derivatives of
(5-16) (0.001 mole) thiourea (0.002 mole)
Experimental
and Na2CO3 (0.002 mole) in absolute
Melting points were recorded on a
ethanol (25 ml) were added. The mixture
Gallen-Kamp MFB-600 melting point
was refluxed for (2-4 hrs), cooled and
apparatus. IR spectra were recorded in
filtered. The filtrate was poured into
KBr disc and film on a Pye-Unicam SP3-
crushed ice, the separated solid was
100 spectrophotometer. UV spectra were
collected
recorded
appropriate solvent (Tables 4,5,6,7).
on
a
Hitachi/UV-2000
and
recrystallized
from
spectrophotometer using absolute ethanol
as solvent. Elemental analyses of some
Results and Discussion
compounds were carried out on C.H.N.
Schiff bases (1-5) were prepared
analyzer type 1160 (Carlo-Erba).
by condensation of 5-ethyl-5-phenyl-1,3-
Preparation of Schiff bases (1-5):
di(acetic acid hydrazide) barbituric acids
-
with various aromatic aldehydes (pClC6H4CHO,
These compounds were prepared
p-OHC6H4CHO,
p-
as reported previously (7,8).
OCH3C6H4CHO, o-NO2C6H4CHO and
Preparation of 5-ethyl-5-phenyl
m-NO2C6H4CHO). The reaction was
followed by the appearance of absorption
barbituric acid derivatives (6-15)
(9)
bands for (υC=N) at (1620-1640 cm-1) in
:-
their IR spectra. In the present work the
To an appropriate Schiff base
reaction of compounds (1-5) with benzoyl
(0.0008 mole), benzoyl chloride or 3,5-
or or 3,5-dinitro benzoyl chlorides and
dinitro benzoyl chloride (0.016 mole) in
subsequent reactions of above reaction
dry benzene (20 ml) was added. The
123
National Journal of Chemistry, 2005, Volume 17
products
(6-15)
with
thiourea
were
under reflux with thiourea in the presence
carried out as shown in scheme (1).
However, treatment
‫المجلد السابع عشر‬-5002-‫المجلة القطرية للكيمياء‬
of Na2CO3 for (2-4 hrs) led to the
nucleophilic substitution of Cl by S S
of-
of Schiff
bases with acid halides results in the
and compounds (16-25) were formed
formation of compounds (6-15) in which
through
two
(Scheme 3).
groups
(Cl
and
ArCO)
were
the
following
NH
NH2
mechanism
introduced in the same step of the
These compounds (16-25) were
reaction. This reaction was followed by
characterized by their IR spectra. New
disappearance of absorption bands at
doublet absorption bands in the region
and
(3200-3450 cm-1) were attributed to
appearance of new absorption bands at
(NH2) and (NH) functional moieties.
(1230-1250 cm-1) and (730-750 cm-1)
Other characteristic bands in the region
which were attributed to (C-N) and (C-
(650-710
Cl) moieties.
moiety. Moreover, ( C-Cl) around (730-
(1620-1640
cm-1)
for
(υC=N)
attack by the azomethine nitrogen at the
carbonyl group of the aroyl chlorides,
displacing the chloride as chloride anion
forming
the
iminium
cation.
However, iminium cation was unstable,
so the Cl- attacked -+N=C moiety and
afforded more stable covalently bonded
compounds (6-15) (Scheme 2).
Moreover, the reactions of acid
halides addition products (6-15) with
thiourea were afforded thioureas products
(16-25). So, heating compounds
correlated
750 cm-1) disappeared.
The reaction was followed the
and
cm-1)
(6-25)
124
to
(C-S)
‫المجلد السابع عشر‬-5002-‫المجلة القطرية للكيمياء‬
National Journal of Chemistry, 2005, Volume 17
O
O
H2N NH C CH2 R' CH2 C NH NH2
O
R C Ar
R
R
O
O
Ar C=N NH C CH2 R' CH2 C NH N=C Ar
(1-5)
O
N
R' =
O
N
, R = H, CH
3
O
Ph C2H5
Ar = o - NO2C6H4, p- HOC6H4, -p ClC6H4,-p MeOC6H4,- m NO2C6H4
3,5-dinitro benzoyl chloride
benzoyl chloride
O
R
R'(CH2 C NH N C Ar)2
O=C Cl
Ar
O
R
R'(CH2 C NH N C Ar)2
O=C Cl
Ar
Ar = C6H5
Ar = 3,5-dinitro benzoyl
(11-15)
(6-10)
thiourea
thiourea
O
R
R'(CH2 C NH N C Ar)2
O=C S
Ar C=NH
NH2
(21-25)
O
R
R'(CH2 C NH N C Ar)2
O=C S
Ar C=NH
NH2
(16-20)
Scheme 1
125
National Journal of Chemistry, 2005, Volume 17
R
NH N=C Ar*
O
Ar** C Cl
R
NH N=C Ar*
O=C O C Cl
Ar**
R
O
Ar** C Cl
O=C
O=C
R
+
O=C
R
NH N=C Ar*
Ar**
O=C R
NH N C Ar*
Cl
O=C
R
O=C
R
NH N C Ar*
O=C Cl
Ar**
Ar* = H, R
Ar** = (i) 3,5-dinitro benzoyl chloride
(ii) benzoyl chloride
O
N
R=
O
‫المجلد السابع عشر‬-5002-‫المجلة القطرية للكيمياء‬
N
O
Ph C2H5
Scheme 2
126
R
NH N=C Ar*
O C Cl
Ar**
National Journal of Chemistry, 2005, Volume 17
S
(1) H2N C NH2
SH
H2N C=NH
Ar**
O=C R
NH N C Ar*
Cl
O=C
(2)
R'
O=C
R
NH N C Ar*
O=C Cl
Ar**
‫المجلد السابع عشر‬-5002-‫المجلة القطرية للكيمياء‬
SH
H2N C=NH
SN
+
2
SH
H2N C=NH
Ar**
O=C R
NH2
NH N C S C
NH
Ar*
O=C
R'
O=C
R
NH2
NH N C S C
NH
O=C Ar*
Ar**
Ar* = H, R
Ar** = (i) 3,5-dinitro benzoyl chloride
(ii) benzoyl chloride
Scheme 3
127
Ar**
O=C R H
NH2
+
NH N C S C
NH
Ar*
O=C
R'
O=C
R H
NH2
+
NH N C S C
NH
O=C Ar*
Ar**
-2 H+
‫المجلة القطرية للكيمياء‪-5002-‬المجلد السابع عشر‬
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9. F. A. Hussein, I. T. Ali and D. F.
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137