An efficient microwave-assisted synthesis of 6,8-dihydroimidazo[1,2-a] [1,3,5] triazine derivatives

Article abstract of DOI:10.1002/jhet.378

(Chemical Equation Presented) A simple, efficient, and general method has been developed for the synthesis of various 4-substituted 2-amino-6,6-diphenyl- 8-aryl-6,8-dihydroimidazo[1,2-a] [1,3,5] triazine-7(4-H)ones 3a-3v. This involved condensation of 1-(5-oxo-4,4-diphenyl-1-aryl-4,5-dihydro-1H-imidazol-2- yl)guanidines 2a and 2b, themselves obtained from the reaction of aryl biguanides 1a/b with benzil, with the requisite carbonyl compounds. Both steps were performed using microwave heating in sealed vessels.

Full text of DOI:10.1002/jhet.378

724
An Efficient Microwave-Assisted Synthesis of
6,8-Dihydroimidazo[1,2-a] [1,3,5] Triazine Derivatives
Vol 47
Mitra Matloobi* and Hans Wolfgang Schramm
Institute of Pharmaceutical Sciences, Karl-Franzens University of Graz, A-8010 Graz, Austria
*E-mail: mitra.matloobi@uni-graz.at
Received October 21, 2009
DOI 10.1002/jhet.378
Published online 11 May 2010 in Wiley InterScience (www.interscience.wiley.com).
A simple, efficient, and general method has been developed for the synthesis of various 4-substituted
2-amino-6,6-diphenyl-8-aryl-6,8-dihydroimidazo[1,2-a] [1,3,5] triazine-7(4-H)ones 3a–3v. This involved
condensation of 1-(5-oxo-4,4-diphenyl-1-aryl-4,5-dihydro-1H-imidazol-2-yl)guanidines 2a and 2b, them-
selves obtained from the reaction of aryl biguanides 1a/b with benzil, with the requisite carbonyl com-
pounds. Both steps were performed using microwave heating in sealed vessels.
J. Heterocyclic Chem., 47, 724 (2010).
INTRODUCTION
potential application as antitumor, antibacterial, and
antiparasitic agents, and as herbicide antagonists [5–21].
Microwave-assisted organic synthesis (MAOS) has
emerged over the past decade as a valuable technology
for synthetic organic and medicinal chemistry. Replac-
ing the conventional oil bath as a heat source by a
microwave reactor results in a marked reduction in reac-
tion time and an increase in reaction yield for many im-
portant transformations [1,2]. In particular, the need for
rapid construction and modification of biologically
active heterocyclic compounds, a major concern in drug
development, has stimulated intense development of
microwave synthesis technology. This is reflected in the
exponential increase in the number of scientific papers,
books, and reviews related to the use of this technology
[3,4].
RESULTS AND DISCUSSION
Imidazoltriazines with structure 3 have been obtained
by a two-step procedure (Scheme 1) involving the heating
of 1-substitued biguanides with benzil to give 1-(5-oxo-
4,4-diphenyl-1-aryl-4,5-dihydro-1H-imidazol-2-yl)guani-
dine intermediates 2 as a mixture of tautomers, and subse-
quent ring closure of these mixtures to the target com-
pounds on further heating [5,22–25].
Transposing this process to microwave conditions, it
was found that the reaction of benzil (1 equiv) with the
1-substituted biguanides 1a and 1b (1 equiv) in ethanol
in a sealed tube (pressure-rated reaction vial) at 100ꢀC
in a self-tuning single-mode microwave cavity (5CEM
Discovery apparatus) was complete after only 2–5 min.
On cooling, the precipitated material was isolated by
simple filtration, washing with cold ethanol, and
In this work, we report a simple and convenient
method for the synthesis of 6,8-dihydroimidazo[1,2-a]
[1,3,5] triazines under microwave irradiation conditions.
The 6,8-dihydroimidazo[1,2-a] [1,3,5] triazine system is
a core structure element in a number of molecules with
C
V
2010 HeteroCorporation

May 2010
An Efficient Microwave-Assisted Synthesis of 6,8-Dihydroimidazo[1,2-a] [1,3,5]
triazine Derivatives
725
Scheme 1
recrystallization to give the known 1-(5-oxo-4,4-di-
phenyl-1-aryl-4,5-dihydro-1H-imidazol-2-yl)guanidines
2a and 2b (73% and 85%, respectively) [22]. These
intermediates were, in turn, reacted with a series of
aldehydes and ketones using microwave irradiation to
construct a 22 member library containing the novel 6,8-
dihydroimidazo[1,2-a] [1,3,5] triazines 3a–3v (Table 1).
In the experiment, compounds 2a or 2b in acetone con-
taining a catalytic amount of acetyl chloride (see Exper-
imental) were place in a sealed vessel and reacted in the
microwave cavity at 100ꢀC. The reaction time was var-
ied from 5 to 20 min in increments of 5 min. However,
in general, the reactions were complete after heating for
10 min, as judged by TLC. When a temperature above
100ꢀC was used a complex reaction mixture was
obtained from which the product was obtained in lower
yield. The mass, IR, and NMR spectra unambiguously
confirmed the structures 3a–3w.
Table 1
Microwave-assisted synthesis of 6,8-dihydroimidazo [1,2-a] [1,3,5] triazines 3a–3v.
Compound
Carbonyl Compound
Acetone
2-Butanone
R1
R2
R3
Time (min)
Yield (%)
3aa
3ba
3ca
3db
3eb
3fb
4-CH3-C6H5
4-CH3-C6H5
4-CH3-C6H5
4-CH3-C6H5
4-CH3-C6H5
4-CH3-C6H5
4-CH3-C6H5
4-CH3-C6H5
4-CH3-C6H5
4-CH3-C6H5
4-CH3-C6H5
4-CH3-C6H5
3,5-Cl2-C6H5
3,5-Cl2-C6H5
3,5-Cl2-C6H5
3,5-Cl2-C6H5
3,5-Cl2-C6H5
3,5-Cl2-C6H5
3,5-Cl2-C6H5
3,5-Cl2-C6H5
3,5-Cl2-C6H5
3,5-Cl2-C6H5
CH3
CH3
CH3
CH3CH2
R2 ¼ R3 ¼ C5H8
4-OCH3-C6H5
2-Cl-C6H5
10
15
20
10
15
5
65
68
50
72
67
72
65
68
69
71
68
54
66
71
67
52
63
58
61
64
63
65
Cyclopentanone
Anizaldehyde
H
H
H
2-Chlorobenzaldehyde
2,4-Dichlorobenzaldehyde
o-Tolyl aldehyde
m-Tolyl aldehyde
4-Biphenylaldehyde
3-Nitrobenzaldehyde
3-(2-Nitrophenyl) propenal
4-Chlorobenzaldehyde
Acetone
2,4-Cl2-C6H5
2-CH3-C6H5
3-CH3-C6H5
C6H5-C6H4
3gb
3hb
3ib
H
H
15
10
20
15
5
H
3jb
H
H
3-NO2-C6H5
2-NO2-C6H5CHCH
2-Cl-C6H5
3kb
3Ib
3ma
3na
3oa
3pa
3qb
3rb
3sb
3tb
H
20
15
20
15
20
10
10
10
10
10
10
CH3
CH3
CH3
CH3
CH3CH2CH2
CH3CH2
2-Pentanone
2-Butanone
Cyclopentanone
R2 ¼ R3 ¼ C5H8
2-CH3-C6H5
3-CH3-C6H5
2-Cl-C6H5
o-Tolyl aldehyde
m-Totyl aldehyde
2-Chlorobenzaldehyde
2,4-Dichlorobenzaldehyde
3-Nitrobenzaldehyde
3-(Nitrophenyl) propenal
H
H
H
H
H
H
2,4-Cl2-C6H5
3-NO2-C6H5
2-NO2-C6H5CHCH
3ub
3vb
a Method A in the Experimental section.
b Method B in the Experimental section.
Journal of Heterocyclic Chemistry
DOI 10.1002/jhet

726
M. Matloobi and H. W. Schramm
Vol 47
and recrystallized from ethanol to give corresponding com-
pound 3.
CONCLUSIONS
An efficient, rapid, and clean method for the prepara-
tion of a 22-membered library of 6,8-dihydroimi-
dazo[1,2-a] [1,3,5] triazines has been developed using
microwave-assisted synthesis.
Method B: General procedure for synthesis of 6,8-dihy-
droimidazo[1,2-a] [1,3,5] triazines (3d–3l and 3q–3v) (car-
bonyl compounds with high boiling point). To a suspension
of 1 equiv arylbiguanide (2a or 2b) (0.1 mmol, 38.3 mg or
43.8 mg) and 5 equiv of the ketone or aldehyde (0.5 mmol) in
ethanol (3mL) in a microwave vial, 5 equiv acetyl chloride
(0.5 mmol, 57.5 mg) was added. The vial was sealed and irra-
diated in a microwave reactor at 100ꢀC for 10–20 min. The
precipitates were collected by filtration and recrystallized from
ethanol to give corresponding compound 3.
EXPERIMENTAL
Materials. All commercially available reagents were used
without further purification. Commercial solvents were dis-
tilled from an appropriate drying agent before use according to
standard procedures.
2-Imino-4,4-dimethyl-8-(4-methylpheyl)-6,6-diphenyl-2,3-
dihydro-4H-imidazo[2,3-d]-1,3,5-triazin-7(6H)one.HCl (3a). mp:
1
255–257ꢀC; H NMR (400 MHz, DMSO) d 1.10 (s, 6H), 2.36
Analysis. TLC analysis was performed on aluminum-pre-
coated silica gel 60 plates. H NMR spectra were recorded on
(s, 3H), 7.33–7.64 (m, 14H), 7.98 (s, 1H), 8.85 (s, 1H), 9.74
(s, 1H); IR (KBr) tmax/cmꢁ1: 3467, 3273, 3091, 2797, 1772,
1658, 1630, 1576, 1534, 1495, 1452, 1192, 967, 698; MS (pos-
itive APCI, m/z): 424 [35, (M þ 1)], 423 (100, M); UV–vis
(MeOH) kmax/nm 207 (0.510).
2-Imino-4-methyl-4-ethyl-8-(4-methylpheyl)-6,6-diphenyl-2,
3-dihydro-4H-imidazo[2,3-d]-1,3,5-triazin-7(6H)one.HCl (3b). mp:
255–257ꢀC; 1H NMR (400 MHz, DMSO) d 0.66 (t, J ¼ 7.2
Hz, 3H), 0.78–0.84 (m, 1H), 1.04–1.11 (m, 1H), 1.37 (s, 3H),
2.35 (s, 3H), 7.32–7.66 (m, 14H), 8.21 (s, 1H), 8.89 (s, 1H),
10.29 (s, 1H); IR (KBr) tmax/cmꢁ1: 3374, 3073, 2970, 2726,
1766, 1678, 1611, 1569, 1513, 1491, 724; MS (positive APCI,
1
a Varian Unity Inova 400 MHz spectrometer using DMSO-d6
as a solvent. Chemical shifts (d) are expressed in ppm down-
field from TMS as internal standard. The letters s, d, t, q, and
m are used to indicate singlet, doublet, triplet, quadruplet, and
multiplet, respectively. IR spectra were taken on a Perkin-
Elmer FT-IR 2000 spectrometer. Low-resolution mass spectra
were obtained in the atmospheric pressure chemical ionization
(positive or negative APCI) mode. All melting points (uncor-
rected) were recorded on a SMP2 apparatus.
Equipment. Microwave syntheses were carried out on a
CEM Corp. Discover laboratory microwave with Explorer
unit. Reaction times refer to hold times at the temperatures
indicated and not to total irradiation time.
m/z): 438 [23, (M þ 1)], 437 (100, M); UV–vis (MeOH) kmax
/
nm 259 (0.179), 249 (0.159), 204 (0.603).
2-Imino-8-(4-methylpheyl)-6,6-diphenyl-4-spirocyclopentanon-
2,3-dihydro-4H-imidazo[2,3-d]-1,3,5-triazin-7(6H)one.HCl
(3c). mp: 270–272ꢀC (dec.); 1H NMR (400 MHz, DMSO) d
1.02–1.86 (m, 8H), 2.10 (s, 3H), 7.34–7.58 (m, 14H), 8.03 (s,
1H), 8.94 (s, 1H), 10.06 (s, 1H); IR (KBr) tmax/cmꢁ1: 3359,
3036, 2962, 2739, 1767, 1681, 1610, 1567, 1490, 1450, 1193,
727, 703; MS (positive APCI, m/z): 450 [25, (M þ 1)], 449
(100, M); UV–vis (MeOH) kmax/nm 205 (0.610).
General procedure for synthesis of 1-(5-Oxo-4,4-di-
phenyl-1-aryl-4,5-dihydro-1H-imidazol-2-yl)guanidines 2a
and 2b. Arylbiguanide hydrochloride (1a and correspondingly
1b, 5 mmol) was added to the solution of sodium (0.11 g, 5
mmol) in absolute ethanol (25 mL). Precipitated sodium chlo-
ride is filtered off and benzil (1.05 g, 5 mmol) dissolved in
absolute ethanol (6 mL) was added to the filtrate in a 30 mL
microwave vial equipped with a pressure and temperature sen-
sor, as well as a magnetic stirrer. The sealed tube was placed
in a homogeneous microwave synthesis system. After irradia-
tion at 100ꢀC, measured by an internal fiber-optic temperature
sensor immersed in the reaction mixture, for 2 (2a) and 5 (2b)
min, respectively, the reaction mixture was cooled, and the
precipitate was collected, washed with cold ethanol, and
recrystallized from ethanol to give highly pure title.
2-Imino-4-(4-methoxyphenyl)-8-(4-methylpheyl)-6,6-diphenyl-
2,3-dihydro-4H-imidazo[2,3-d]-1,3,5-triazin-7(6H)one.HCl
1
(3d). mp: 274–276ꢀC; H NMR (400 MHz, DMSO) d 0.66 (t,
J ¼ 7.2 Hz, 3H), 1.08 (m, 2H), 1.37 (s, 3H), 7.54–7.86 (m,
13H), 8.23 (s, 1H), 8.95 (s, 1H), 10.01 (s, 1H), IR (KBr) tmax
/
cmꢁ1: 3353, 3053, 2795, 1777, 1674, 1611, 1588, 1487, 728,
712; MS (positive APCI, m/z): 502 [37, (M þ 1)], 501 (100,
M); UV–vis (MeOH) kmax/nm 207 (0.554).
2-[1-(4-Methylphenyl)-5-oxo-4,4-diphenyl-2-imidazolline-2-
1
2-Imino-4-(2-chlorophenyl)-8-(4-methylpheyl)-6,6-diphenyl-
2,3-dihydro-4H-imidazo[2,3-d]-1,3,5-triazin-7(6H)one.HCl
yl]-guanidines (2a). H NMR (400 MHz, DMSO) d 2.34 (s,
3H), 7.53–7.90 (m, 14H); IR (KBr) tmax/cmꢁ1: 3115, 3166,
3061, 1593, 1537; UV–vis (MeOH) kmax/nm 204 (0.406).
2-[1-(3,5-Dichlorophenyl)-5-oxo-4,4-diphenyl-2-imidazolline-
1
(3e). mp: 277–279ꢀC; H NMR (400 MHz, DMSO) d 238 (s,
3H), 6.52 (s, 1H), 7.05–7.64 (m, 18H), 8.33 (s, 1H), 9.03 (s,
1H), 10.18 (s, 1H); IR (KBr) tmax/cmꢁ1: 3366, 3000, 2670,
1770, 1677, 1616, 1573, 1488, 1195, 760, 728; MS (positive
APCI, m/z): 507 [40, (M þ 2)], 506 [47, (M þ 1)], 505 (100,
M); UV–vis (MeOH) kmax/nm 205 (0.569).
1
2-yl]-guanidines (2b). H NMR (400 MHz, DMSO) d 7.21–
7.98 (m, 13H); IR (KBr) tmax/cmꢁ1: 3430, 3176, 3084, 1709,
1640, 1611, 1597, 1536, 798, 747, 697; UV–vis (MeOH) kmax
nm 206 (0.688).
/
2-Imino-4-(2,4-dichlorophenyl)-8-(4-methylpheyl)-6,6-diphenyl-
2,3-dihydro-4H-imidazo[2,3-d]-1,3,5-triazin-7(6H)one.HCl
Method A: General procedure for synthesis of 6,8-dihy-
droimidazo[1,2-a] [1,3,5] triazines (3a–3c and 3m–3p) (car-
bonyl compounds with low boiling point). To a suspension
of 1 equiv arylbiguanide (2a or 2b) (0.1 mmol, 38.3 mg or
43.8 mg) in 3 mL of ketone or aldehyde in a microwave vial,
5 equiv acetyl chloride (0.5 mmol, 57.5 mg) was added. The
vial was sealed and irradiated in a microwave reactor at 100ꢀC
for 10–20 min. The precipitates were collected by filtration
1
(3f). mp: 278–280ꢀC; H NMR (400 MHz, DMSO) d 2.38 (s,
3H), 6.55 (s, 1H), 7.11–7.63 (m, 17H), 8.23 (s, 1H), 9.04 (s,
1H), 10.21 (s, 1H); IR (KBr) tmax/cmꢁ1: 3356, 3036, 2623,
1766, 1679, 1616, 1579, 1492, 1191, 762, 733, 693; MS (posi-
tive APCI, m/z): 541 [70, (M þ 2)], 539 (100, M); UV–vis
(MeOH) kmax/nm 206 (0.531).
Journal of Heterocyclic Chemistry
DOI 10.1002/jhet

May 2010
An Efficient Microwave-Assisted Synthesis of 6,8-Dihydroimidazo[1,2-a] [1,3,5]
triazine Derivatives
727
17H), 8.03 (s, 1H), 8.88 (s, 1H), 9.76 (s, 1H); IR (KBr) tmax
/
2-Imino-4-(2-methylpheyl)-8-(4-methylpheyl)-6,6-diphenyl-2,
3-dihydro-4H-imidazo[2,3-d]-1,3,5-triazin-7(6H)one.HCl (3g). mp:
cmꢁ1: 3360, 3026, 2778, 1777, 1675, 1613, 1589, 1492, 1197,
759, 727; MS (positive APCI, m/z): 507 [50, (M þ 2)], 506
[27, (M þ 1)], 505 (100, M); UV–vis (MeOH) kmax/nm 206
(0.887).
1
278–280ꢀC; H NMR (400 MHz, DMSO) d 2.15 (s, 3H), 2.39
(s, 3H), 6.38 (s, 1H), 6.85–7.60 (m, 18H), 8.23 (s, 1H), 8.95
(s, 1H), 10.15 (s, 1H); IR (KBr) tmax/cmꢁ1: 3360, 3021, 2702,
1769, 1677, 1616, 1573, 1486, 1192, 725; MS (positive APCI,
2-Imino-4-methyl-4-ethyl-8-(3,5-dichlorophenyl)-6,6-diphenyl-2,
3-dihydro-4H-imidazo[2,3-d]-1,3,5-triazin-7(6H)one.HCl (3o). mp:
265–267ꢀC; 1H NMR (400 MHz, DMSO) d 0.66 (t, J ¼ 7.2
Hz, 3H), 1.08 (m, 2H), 1.37 (s, 3H), 7.54–7.86 (m, 13H), 8.23
(s, 1H), 8.95 (s, 1H), 10.01 (s, 1H); IR (KBr) tmax/cmꢁ1
3353, 3053, 2795, 1777, 1674, 1611, 1588, 1487, 728, 712;
MS (positive APCI, m/z): 492 [60, (M þ 1)], 491 (85, M), 437
[80, (M-54)]; UV–vis (MeOH) kmax/nm 207 (0.554).
2-Imino-8-(3,5-dichlorophenyl)-6,6-diphenyl-4-spirocyclopenta-
non-2,3-dihydro-4H-imidazo[2,3-d]-1,3,5-triazin-7(6H)one.HCl
(3p). mp: 267–269ꢀC (dec.); 1H NMR (400 MHz, DMSO) d
1.01–2.06 (m, 8H), 7.54–7.89 (m, 13H), 8.07 (s, 1H), 9.00 (s,
1H), 10.08 (s, 1H); IR (KBr) tmax/cmꢁ1: 3360, 3021, 2800,
1778, 1676, 1611, 1588, 1486, 1186, 727, 710; MS (positive
APCI, m/z): 505 [75, (M þ 2)], 504 [35, (M þ 1)], 503 (100,
M); UV–vis (MeOH) kmax/nm 207 (0.452).
m/z): 486 [27, (M þ 1)], 485 (100, M); UV–vis (MeOH) kmax
/
nm 206 (0.720).
2-Imino-4-(3-methylpheyl)-8-(4-methylpheyl)-6,6-diphenyl-2,
3-dihydro-4H-imidazo[2,3-d]-1,3,5-triazin-7(6H)one.HCl (3h). mp:
:
1
220–222ꢀC; H NMR (400 MHz, DMSO) d 2.28 (s, 3H), 2.39
(s,3H), 6.33 (s,1H), 6.66–7.61 (m, 18H), 8.16 (s, 1H), 8.98 (s,
1H), 10.07 (s, 1H); IR (KBr) tmax/cmꢁ1: 3423, 3108, 2951,
1767, 1650, 1610, 1581, 1498, 1180, 696, 486; MS (positive
APCI, m/z): 486 [25, (M þ 1)], 485 (100, M); UV–vis
(MeOH) kmax/nm 207 (0.529).
2-Imino-4-(biphenyl-4-yl)-8-(4-methylpheyl)-6,6-diphenyl-2,
3-dihydro-4H-imidazo[2,3-d]-1,3,5-triazin-7(6H)one.HCl (3i). mp:
1
257–259ꢀC; H NMR (400 MHz, DMSO) d 2.39 (s, 3H), 6.48
(s, 1H), 7.04–7.62 (m, 23H), 8.54 (s, 1H), 9.03 (s, 1H), 10.17
(s, 1H); IR (KBr) tmax/cmꢁ1: 3352, 3060, 2747, 1768, 1665,
1615, 1579, 1495, 1193, 764, 732, 697; MS (positive APCI,
2-Imino-4-(2-methylpheyl)-8-(3,5-dichlorophenyl)-6,6-diphenyl-2,
3-dihydro-4H-imidazo[2,3-d]-1,3,5-triazin-7(6H)one.HCl (3q). mp:
m/z): 548 [47, (M þ 1)], 547 (100, M); UV–vis (MeOH) kmax
/
nm 260 (0.179), 243 (0.155), 205 (0.433).
1
273–275ꢀC; H NMR (400 MHz, DMSO) d 2.19 (s, 3H), 6.38
2-Imino-4-(3-nitrophenyl)-8-(4-methylpheyl)-6,6-diphenyl-2,
3-dihydro-4H-imidazo[2,3-d]-1,3,5-triazin-7(6H)one.HCl (3j). mp:
276–279ꢀC; 1H NMR (400 MHz, DMSO) d 2.39 (s, 3H),
6.69–7.99 (m, 18H), 8.46 (s, 1H), 9.10 (s, 1H), 10.27 (s, 1H);
IR (KBr) tmax/cmꢁ1: 3187, 3096, 2960, 1771, 1675, 1650,
1606, 1493, 1193, 690; MS (positive APCI, m/z): 518 [17, (M
þ 2)], 516 (100, M); UV–vis (MeOH) kmax/nm 206 (0.606).
2-Imino-4-(2-nitrostyryl)-8-(4-methylpheyl)-6,6-diphenyl-2,3-
dihydro-4H-imidazo[2,3-d]-1,3,5-triazin-7(6H)one.HCl (3k). mp:
279–281ꢀC (dec.); 1H NMR (400 MHz, DMSO) d 2.36 (s,
3H), 5.95 (d, J ¼ 8.4 Hz, 1H), 6.11 (dd, J1 ¼ 15.6 Hz, J2 ¼
8.4 Hz, 1H) 6.49 (d, J ¼ 14.2 Hz, 1H), 7.07–7.86 (m, 16H),
7.85 (d, J ¼ 7.8 Hz, 1H), 8.26 (s, 1H), 9.00 (s, 1H), 9.71 (s,
1H); IR (KBr) tmax/cmꢁ1: 3424, 3115, 2363, 1773, 1675,
1660, 1612, 1518, 1198, 768, 695; MS (positive APCI, m/z):
543 [37, (M þ 1)], 542 (100, M); UV–vis (MeOH) kmax/nm
205 (0.466).
(s, 1H), 8.00–6.38 (m, 17H), 8.47 (s, 1H), 9.04 (s, 1H), 10.24
(s, 1H); IR (KBr) tmax/cmꢁ1: 3368, 3046, 2695, 1773, 1675,
1617, 1590, 1482, 759, 729, 706; MS (positive APCI, m/z):
541 [70, (M þ 1)], 539 (100, M); UV–vis (MeOH) kmax/nm,
207 (0.425).
2-Imino-4-(3-methylpheyl)-8-(3,5-dichlorophenyl)-6,6-diphenyl-
2,3-dihydro-4H-imidazo[2,3-d]-1,3,5-triazin-7(6H)one.HCl
1
(3r). mp: 269–271ꢀC; H NMR (400 MHz, DMSO) d 2.49 (s,
3H), 6.30 (s, 1H), 6.67–7.96 (m, 17H), 8.39 (s, 1H), 9.00 (s, 1H),
9.98 (s, 1H); IR (KBr) tmax/cmꢁ1: 3358, 3059, 2696, 1776, 1677,
1659, 1619, 1575, 1490, 1187, 751, 697; MS (positive APCI, m/
z): 541 [83, (M þ 2)], 539 (100, M), 538 [55, (M-1)]; UV–vis
(MeOH) kmax/nm 207 (0.383).
2-Imino-4-(2-chlorophenyl)-8-(3,5-dichlorophenyl)-6,6-diphenyl-
2,3-dihydro-4H-imidazo[2,3-d]-1,3,5-triazin-7(6H)one.HCl
1
(3s). mp: 280–282ꢀC; H NMR (400 MHz, DMSO) d 6.51 (s,
1H), 7.05–7.61 (m, 17H), 8.24 (s, 1H), 9.10 (s, 1H), 10.15 (s,
1H); IR (KBr) tmax/cmꢁ1: 3355, 3021, 2688, 1774, 1673, 1613,
1481, 1197, 758, 706; MS (positive APCI, m/z): 561 [100, (M
2-Imino-4-(4-chlorophenyl)-8-(4-methylpheyl)-6,6-diphenyl-
2,3-dihydro-4H-imidazo[2,3-d]-1,3,5-triazin-7(6H)one.HCl
1
(3l). mp: 283–285ꢀC; H NMR (400 MHz, DMSO) d 2.38 (s,
þ 2)], 560 [40, (M þ 1)], 559 (55, M); UV–vis (MeOH) kmax
/
3H), 6.47 (s, 1H), 7.08–7.61 (m, 18H), 8.43 (s, 1H), 9.02 (s,
1H), 10.13 (s, 1H); IR (KBr) tmax/cmꢁ1: 3368, 3086, 2682,
1779, 1672, 1613, 1578, 1494, 1192, 728, 697; MS (positive
APCI, m/z): 506 [55, (M þ 1)], 505 (100, M); UV–vis
(MeOH) kmax/nm 206 (0.456).
2-Imino-4,4-dimethyl-8-(3,5-dichlorophenyl)-6,6-diphenyl-2,
3-dihydro-4H-imidazo[2,3-d]-1,3,5-triazin-7(6H)one.HCl (3m). mp:
271–273ꢀC; 1H NMR (400 MHz, DMSO) d 1.10 (s, 6H),
7.55–7.86 (m, 13H), 8.04 (s, 1H), 8.92 (s, 1H), 9.80 (s, 1H);
IR (KBr) tmax/cmꢁ1: 3361, 3022, 2755, 1780, 1678, 1614,
1588, 1491, 1454, 1427, 1174, 1029, 728; MS (positive APCI,
m/z): 479 [95, (M þ 2)], 478 [35, (M þ 1)], 477 (100, M);
UV–vis (MeOH) kmax/nm 208 (0.469).
nm 208 (0.419).
2-Imino-4-(2,4-dichlorophenyl)-8-(3,5-dichlorophenyl)-6,6-
diphenyl-2,3-dihydro-4H-imidazo[2,3-d]-1,3,5-triazin-7(6H)one.
HCl (3t). mp: 270–272ꢀC; 1H NMR (400 MHz, DMSO) d 6.54
(s, 1H), 7.07–7.95 (m, 16H), 8.51 (s, 1H), 9.15 (s, 1H), 10.40 (s,
1H); IR (KBr) tmax/cmꢁ1: 3355, 3062, 2680, 1781, 1673, 1617,
1587, 1494, 1449, 1186, 752, 698; MS (positive APCI, m/z): 597
[30, (M þ 1)], 595 (M, 100), 593 [60, (M-2)]; UV–vis (MeOH)
k
max/nm 208 (0.325).
2-Imino-4-(3-nitrophenyl)-8-(3,5-dichlorophenyl)-6,6-diphenyl-
2,3-dihydro-4H-imidazo[2,3-d]-1,3,5-triazin-7(6H)one.HCl
1
(3u). mp: 274–276ꢀC; H NMR (400 MHz, DMSO) d 6,70 (s,
2-Imino-4-methyl-4-propyl-8-(3,5-dichlorophenyl)-6,6-diphenyl-
2,3-dihydro-4H-imidazo[2,3-d]-1,3,5-triazin-7(6H)one.HCl
(3n). mp: 248–252ꢀC; 1H NMR (400 MHz, DMSO) d 0.50–
0.53 (t, J ¼ 7.2 Hz, 3H), 0.66–0.75 (m, 2H), 1.03–1.19
(m, 1H), 1.19–1.23 (M, 1H), 1.43 (s, 3H), 7.34–7.87 (m,
1H), 7.00–7.98 (m, 17H), 8.51 (s, 1H), 9.11 (s, 1H), 10.31 (s,
1H); IR (KBr) tmax/cmꢁ1: 3349, 3065, 2667, 1787, 1680,
1620, 1527, 1493, 1187, 753, 693, 680; MS (positive APCI,
m/z): 572 [55, (M þ 2)], 570 (100, M); UV–vis (MeOH) kmax
/
nm 206 (0.497).
Journal of Heterocyclic Chemistry
DOI 10.1002/jhet

728
M. Matloobi and H. W. Schramm
Vol 47
[8] Schiewald, E.; Graubaum, H. W.; Martin, H. D.; Steinke,
W.; Kramer, W.; Lange, N.; Mory, W.; Wolter, G. DD Pat. 2,27,035
(1985); Chem Abstr 104, 143975.
2-Imino-4-(2-nitrostyryl)-8-(3,5-dichlorophenyl)-6,6-diphenyl-2,
3-dihydro-4H-imidazo[2,3-d]-1,3,5-triazin-7(6H)one.HCl (3v). mp:
280–282ꢀC (dec.); 1H NMR (400 MHz, DMSO) d 5.98–6.07
(m, 2H), 6.51 (d, J ¼ 14.2 Hz, 1H), 7.06–7.92 (m, 16H), 8.39
(s, 1H), 9.07 (s, 1H), 9.83 (s, 1H); IR (KBr) tmax/cmꢁ1: 334,
3028, 2787, 1773, 1679, 1664, 1612, 1523, 1487, 1185, 734,
699; MS (positive APCI, m/z): 598 [97, (M þ 2)], 597 [70, (M
þ 1)], 596 (100, M); UV–vis (MeOH) kmax/nm 207 (0.614).
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W.; Kramer, W.; Lange, N.; Mory, W.; Wolter, G. DD Pat. 2,27,035
(1985); Chem Abstr 104, 143975.
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Journal of Heterocyclic Chemistry
DOI 10.1002/jhet