Reactions of 4,7-Dihydro-1,2,4-triazolo[1,5-a]pyrimidines with α,β-Unsaturated Carbonyl Compounds

Article abstract of DOI:10.1002/jhet.5570400618

The reaction of 5,7-diphenyl-4,7-dihydro-1,2,4 -triazolo[1,5-7]pyrimidine (1) with α,β-unsaturated carbonyl compounds 2a-f led to the formation of the alkylated heterocycles 3a-f (Figure 1). However, the reaction of 5-methyl-7-phenyl-4,7-dihydro-1,2,4-triazolo[1,5-a] pyrimidine (5) with 2a-c yielded under the same conditions the triazolo[5,1-b]quinazolines 6a-c (Figure 3). In this case, the alkylation is followed by a cyclocondensation. The structure elucidation of the products is based on ir, ms, ¹H and ¹³C nmr measurements and on an X-ray diffraction study.

Full text of DOI:10.1002/jhet.5570400618

Nov-Dec 2003
1081
Reactions of 4,7-Dihydro-1,2,4-triazolo[1,5-a]pyrimidines with α,β-
Unsaturated Carbonyl Compounds
Victoria V. Lipson[a], Irina V. Ignatenko[a], Sergey M. Desenko[b], Svetlana V.
*
Shishkina[b], Oleg V. Shishkin[b], Sergey A. Komykhov[c] , Natalya V.
Logvinenko[c], Valery D. Orlov[c], and Herbert Meier[d]
[a]Antidiabetic Drug Laboratory, V. Danilevsky Institute of Endocrine Pathology Problems,
Artema St. 10, 61002 Kharkov, Ukraine
[b]Ukrainian National Academy of Sciences, Institute for Single Crystals,
Lenina Av. 60, 61000, Kharkov, Ukraine
[c]Department of Chemistry, Kharkov National University, Svobody Sq. 4,
61077 Kharkov, Ukraine
[d]Institute of Organic Chemistry, University of Mainz, D-55099 Mainz, Germany
Received June 26, 2003
The reaction of 5,7-diphenyl-4,7-dihydro-1,2,4-triazolo[1,5-a]pyrimidine (1) with α,β-unsaturated
carbonyl compounds 2a-f led to the formation of the alkylated heterocycles 3a-f (Figure 1). However, the
reaction of 5-methyl-7-phenyl-4,7-dihydro-1,2,4-triazolo[1,5-a]pyrimidine (5) with 2a-c yielded under the
same conditions the triazolo[5,1-b]quinazolines 6a-c (Figure 3). In this case, the alkylation is followed by a
1
13
cyclocondensation. The structure elucidation of the products is based on ir, ms, H and C nmr measure-
ments and on an X-ray diffraction study.
J. Heterocyclic Chem., 40, 1081 (2003).
Introduction.
In previous years, fused dihydroazolopyrimidine sys-
tems have received considerable attention not only as com-
pounds for pharmacological tests, but also as convenient
models for the solution of a number of problems in the
field of synthetic chemistry of partially hydrogenated hete-
rocycles. Investigation of their chemical properties, molec-
ular structure and imine - enamine tautomeric equilibrium
have been reported recently [1-4].
The 4,7-dihydro-1,2,4-triazolo[1,5-a]pyrimidines 1 and
5 (Figures 1 and 3), which contain an enamine substructure
NH C(R)=CH , represent ambident nucleophiles.
The nitrogen atom N-4 is their hard and the carbon atom
C-6 their soft center. In our previous investigations, we
found that alkylation selectively takes place at the N-4 but
Compound R1
R2
mp [°C]
Yield [%]
3a
3b
3c
3d
3e
3f
C6H5
C6H5
C6H5
C6H5
4-CH3-C6H4
C6H5
C6H5
222 – 224
221
229
250 – 252
251
230 - 232
58
56
68
67
61
46
4-CH3O-C6H4
4-Cl-C6H4
4-F-C6H4
C6H5
CO-C6H5
not at the C-6 atom, when soft electrophiles like CH I or
3
hard electrophiles like Me SO were used [2,4]. In the pre-
2
4
sent article we report on opposite results when the alkyla-
tion of compound 1 or 5 is performed using α,β-unsatu-
rated carbonyl compounds.
Figure 1. Alkylation of 4,7-dihydro-5,7-diphenyl-1,2,4-triazolo-
[1,5-a]pyrimidines.
Results and Discussion.
Equimolar amounts of 4,7-dihydro-5,7-diphenyl-1,2,4-
triazolo[1,5-a]pyrimidine (1) and an α,β-unsaturated car-
bonyl compound (2a-f) were refluxed in methanol in the
presence of sodium methoxide. Adducts 3a-f were formed
in yields between 46 and 68 %. The same products were
obtained in a one-pot synthesis, when the reaction between
one mole of 3-amino-1,2,4-triazole (4) and two moles of
chalcone was carried out under similar conditions. The for-
mation of 3a from 4 and 2a is shown in Figure 1 as an
example.
The structures of the compounds 3a-f were established by
spectroscopic methods. Their ir spectra (potassium bromide
pellets) show characteristic absorptions at 3400 - 2850, 1724 -
-1
1684 and 1660 - 1652 cm indicating the presence of H-
bonding NH groups, C=O and C=C double bonds. High reso-
1
lution H nmr spectra of compounds 3a-f (Table 1) contain
singlets for 2-H, 4-H and 7-H, ABM spin patterns for the side
chain on C-6 and a multiplet for the aromatic protons. The
13
C nmr spectra of 3a-f exhibit signals of the side chain, five

1082
V. V. Lipson, I. V. Ignatenko, S. M. Desenko, S. V. Shishkina, O. V. Shishkin,
S. A. Komykhov, N. V. Logvinenko, V. D. Orlov, and H. Meier
Vol. 40
signals of the dihydrotriazolopyrimidine scaffold and
strongly overlapping signals of the aromatic rings. The signal
assignments in Table 2 are based on DEPT measurements.
Finally, the structure of 3a was confirmed by an X-ray
crystal structure analysis. Figure 2 shows a perspective
view of the molecule of 3a. (The numbers used to indicate
Table 1
1
H nmr Data of Compounds 3a-f (δ Values in (CD ) SO, TMS as Internal Standard)
3 2
Compound
NH
s
Ar-H
m
2-H
s
7-H
s
Sidechain on C-6 (ABM)
CH
3
C-H
H-C-H
s
3a
3b
3c
3d
3e
3f
9.75
9.89
9.95
9.93
9.91
10.22
6.95 – 7.65
6.77 – 7.65
6.95 – 7.68
6.94 – 7.69
6.93 – 7.68
7.41 – 7.53
[a]
5.70
5.54
5.57
5.56
5.51
5.69
4.69
4.36
4.38
4.39
4.40
4.83
3.08
3.02
3.07
3.06
3.05
3.23
2.68
2.74
2.85
2.83
2.67
2.77
7.43
7.45
7.44
7.43
[a]
3.68
2.23
[a] superimposed on the signals of the aromatic protons
Table
2
13
C nmr Data of Compounds 3a-f (δ Values in (CD ) SO, TMS as Internal Standard)
3 2
CH
CH
C-7
C-6
C-5
C-2
C-3a
CO
Aromat. C [a]
CH
3
2
3a
3b
3c
3d
3e
3f
40.9
41.1
40.9
41.3
40.8
42.8
39.5
59.7
108.2
142.1
149.6
148.2
196.6
126.2, 126.3, 126.9, 127.1, 127.5, 128.2, 128.2, 128.4,
128.7, 132.8, 133.9, 135.0, 136.0, 141.0,
127.3, 127.7, 128.1, 128.5, 128.7, 129.0, 129.5,
132.8, 133.1, 133.6, 135.1, 136.0, 157.7
127.4, 127.8, 128.4, 128.5, 128.7, 128.9, 128.9,
129.1, 129.5, 130.9, 133.2, 134.3, 134.9, 135.9
127.3, 127.8, 128.4, 128.7, 128.9, 129.5,
38.7
38.8
38.9
39.3
40.6
59.6
59.7
59.9
59.7
60.1
108.5
107.7
108.1
108.3
101.4
142.1
142.0
142.0
142.3
142.0
149.6
149.7
149.7
149.7
149.9
148.2
148.1
148.3
148.2
148.0
196.7
196.5
196.6
196.1
54.9
21.0
128.8, 129.0, 128.5, 137.3, 160.7
126.4, 127.1, 127.4, 127.7, 128.4, 128.5, 128.7,
129.0, 129.1, 129.5, 133.6, 133.8, 135.1, 141.1, 143.5
127.3, 127.7, 127.9, 128.5, 128.6, 128.7, 128.8,
129.0, 129.3, 129.6, 133.3, 134.2, 135.6, 135.7, 136.5
197.1,
197.9
[a] The signals of the aromatic carbon atoms are strongly superimposed
Table 3
Bond Lengths [Å] in 3a
O (1) – C (14)
N (1) – N (2)
N (2) – C (5)
N (3) – C (1)
N (4) – C (3)
C (3) – C (6)
C (4) – C (12)
C (6) – C (7)
1.231 (9)
1.384 (7)
1.468 (9)
1.365 (10)
1.407 (9)
1.474 (10)
1.528 (10)
1.382 (10)
1.392 (11)
1.354 (10)
1.495 (10)
1.505 (10)
1.344 (11)
1.415 (13)
1.334 (14)
1.370 (11)
1.375 (12)
1.37 (2)
N (1) – C (1)
N (2) – C (2)
N (3) – C (2)
N (4) – C (2)
C (3) – C (4)
C (4) – C (5)
C (5) – C (27)
C (6) – C (11)
C (8) – C (9)
C (10) – C (11)
C (12) – C (13)
C (14) – C (15)
C (15) – C (20)
C (17) – C (18)
C (19) – C (20)
C (21) – C (22)
C (23) – C (24)
C (25) – C (26)
C (27) – C (32)
C (29) – C (30)
C (31) – C (32)
1.300 (10)
1.336 (9)
1.332 (9)
1.343 (9)
1.343 (10)
1.534 (10)
1.526 (10)
1.399 (10)
1.377 (11)
1.365 (10)
1.534 (9)
1.490 (11)
1.390 (11)
1.360 (14)
1.382 (14)
1.386 (11)
1.371 (14)
1.378 (13)
1.370 (10)
1.37 (2)
C (7) – C (8)
C (9) – C (10)
C (12) – C (21)
C (13) – C (14)
C (15) – C (16)
C (16) – C (17)
C (18) – C (19)
C (21) – C (26)
C (22) – C (23)
C (24) – C (25)
C (27) – C (28)
C (28) – C (29)
C (30) – C (31)
1.367 (10)
1.374 (13)
1.347 (14)
Figure 2. Perspective view of compound 3a.
1.378 (12)

Nov-Dec 2003
4,7-Dihydro-1,2,4-triazolo[1,5-a]pyrimidines
1083
Table 4
Selected Bond (ϖ) and Torsion (τ) Angles for Compound 3a
Bond angle
ϖ
Torsion angle
τ
C (4) – C (3) – C (6)
125.5 (7)
112.7 (7)
122.8 (7)
114.4 (6)
110.5 (6)
113.2 (6)
108.9 (6)
114.3 (6)
119.2 (7)
118.8 (8)
126.1 (8)
116.8 (8)
119.6 (8)
120.5 (8)
121.8 (7)
121.1 (7)
122.8 (8)
118.2 (8)
C (3) – N (4) – C (2) – N (2)
C (5) – N (2) – C (2) – N (4)
C (2) – N (4) – C (3) – C (4)
N (4) – C (3) – C (4) – C (5)
C (6) – C (3) – C (4) – C (12)
C (2) – N (2) – C (5) – C (4)
C (3) – C (4) – C (5) – N (2)
C (3) – C (4) – C (5) – C (27)
C (3) – C (4) – C (12) – C (21)
C (3) – C (4) – C (12) – C (13)
C (4) – C (12) – C (13) – C (14)
C (12) – C (13) – C (14) – O (1)
O (1) – C (14) – C (15) – C (20)
C (13) – C (12) – C (21) – C (26)
N (2) – C (5) – C (27) – C (32)
C (4) – C (5) – C (27) – C (32)
C (3) – C (4) – C (12) – H (12)
H (5) – C (5) – C (27) – C (28)
13 (1)
-5 (1)
-9 (1)
-3 (1)
-10 (1)
-6 (1)
10.0 (9)
-112.2 (8)
-118.4 (8)
112.8 (8)
-165.7 (7)
36 (1)
21 (1)
21 (1)
-73.6 (8)
46.7 (9)
-4 (1)
N (4) – C (3) – C (6)
C (3) – C (4) – C (12)
C (5) – C (4) – C (12)
N (2) – C (5) – C (27)
C (27) – C (5) – C (4)
C (21) – C 12) – C (4)
C (21) – C (12) – C (13)
O (1) – C (14) – C (15)
O (1) – C (14) – C (13)
C (26) – C (21) – C (12)
C (22) – C (21) – C (12)
C (28) – C (27) – C (5)
C (32) – C (27) – C (5)
C (7) – C (6) – C (3)
C (11) – C (6) – C (3)
C (16) – C (15) – C (14)
C (20) – C (15) – C (14)
-3 (1)
atoms do not correspond to nomenclature). Selected bond
lengths, bond angles and torsion angles are listed in Tables
3 and 4.
bond. (The C(12)-C(13)-C(14)-O(1) torsion angle is
36(1)°). The phenyl group at C(5) has pseudoaxial orienta-
tion (the C(3)-C(4)-C(5)-C(27) torsion angle is
–112.2(8)°) and is almost coplanar to the H(5) – C(5)
bond. The H(5)-C(5)-C(27)-C(28) torsion angle is –3(1)°).
Compound 3a exists in the crystalline phase as a mono-
hydrate. According to the crystal structure analysis, mole-
cules of 3a, like other 4,7-dihydroazolopyrimidines [5,8-
10], form dimers due to intermolecular hydrogen bonds.
Under the same conditions 4,7-dihydro-5-methyl-7-
phenyl-triazolo[1,5-a]pyrimidine (5) undergoes alkylation at
C-6 followed by a cyclocondensation to yield 4,7,8,9-tetrahy-
dro-1,2,4-triazolo[5,1-b]quinazolines (6a-c, Figure 3).
The conformation of the dihydropyrimidine ring can be
described as flattened boat (puckering coordinates [5]: S =
0.18, Θ = 81.72, Ψ = 18.86); the deviation of the N(4) and
C(5) atoms from the plane of the remaining atoms of the
ring is –0.11 Å. Essential flattening of the 6-membered
ring in this compound as compared to the 5-phenyl-7-
tolyl-4,7-dihydro derivative [6,7] is probably caused by
considerable strengthening of the 1,2-allyl interactions
along the C(4)-C(5) bond. The shortened intramolecular
contacts between C(7) and H(12) of 2.74 Å (the van der
Waals radii sum is 2.87 Å [8]), between H(5) and C(21)
of 2.53 Å, H(5) and C(26) of 2.82 Å, C(27) and C(13) of
3.15 Å and C(27) and H(13b) of 2.65 Å indicate consider-
able steric strain within the threefold substituted C(3)-
C(4)-C(5) fragment. This leads to significant deformations
of the exocyclic bond angles at C(3), C(4) and C(5) (Table
3) and to the twist of the substituents at C(3) and C(4) with
respect to each other. The C(6)-C(3)-C(4)-C(12) torsion
angle amounts to –10(1)° and the C(4)-C(3)-C(6)-C(7) tor-
sion angle amounts to –60(1)° as compared to other 5-
phenyl substituted 4,7-dihydrotriazolopyrimidines where
the latter torsion angle is about 40° [1,4-6]. The phenyl
group on C(12) is turned by 21(1)° relative to the C(12)-
C(13) bond (C(13)-C(12)-C(21)-C(26) torsion angle),
what probably results from the shortened intramolecular
contact of 2.17 Å between H(13b) and H(26). The interac-
tion between the H(13b) and H(16) with a distance of 2.10
Å causes the non-planarity of the benzyl group (the O(1)-
C(14)-C(15)-C(20) torsion angle amounts to 21(1)°) and
the rotation of the substituent around the C(13)-C(14)
Compound R1
R2
mp [°C]
Yield [%]
6a
6b
6c
C6H5
C6H5
C6H5
C6H5
4-CH3O-C6H4
4-Cl-C6H4
240 – 243
243 – 245
252 - 255
53
42
44
Figure 3. Preparation of Compounds 6a-c.
The structure of compounds 6a-c was established by
spectral methods. The ir spectra prove the absence of a
C=O group but the presence of an H-bonding NH-group
-1
1
absorbing at 3300 – 2650 cm . The H nmr spectra

1084
V. V. Lipson, I. V. Ignatenko, S. M. Desenko, S. V. Shishkina, O. V. Shishkin,
S. A. Komykhov, N. V. Logvinenko, V. D. Orlov, and H. Meier
Vol. 40
General Procedure for the Alkylation of 4,7-Dihydro-5,7-
diphenyl-1,2,4-triazolo[1,5-a]pyrimidine (1).
(Table 5) of compounds 6a-c show the absence of a methyl
signal but contain singlets for the methine and the NH pro-
tons, the methoxy protons of 6b, and furthermore the four-
spin system of the carbocyclic ring. One of the latter four
signals is located in the olefinic region at 6.48 ppm, the
others are in the region of aliphatic protons. Decoupling of
A solution of 0.08 g (1.5 mmol) of sodium methoxide, 0.30 g
(1.1 mmol) of 4,7-dihydro-5,7-diphenyl-1,2,4-triazolo[1,5-
a]pyrimidine (1) and 1.2 mmol of an α,β-unsaturated carbonyl
compound 2a-f in 10 mL of methanol was refluxed for 2 h. After
cooling, the products 3a-f were isolated by filtration, washed
with methanol, dried and recrystallized from a 2:1 mixture of
methanol and dimethylformamide. Yields and melting points are
4
the signal at 6.48 ppm ( J = 2.4 Hz) leads to the typical
13
spectrum of an ABM system. The C nmr spectra (Table
6) confirmed additionally the structure of compounds 6a-c.
(The signal assignment is based on DEPT, HMQC and
HMBC experiments).
1
13
summarized in Figure 1; H and C nmr spectral data are listed
in Tables 1 and 2.
Table 5
H nmr Data of the Compounds 6a-c (δ Values in (CD ) SO, TMS as Internal Standard)
1
3 2
Compound
NH
s
Ar-H
m
2-H
s
5-H
7-H
8-H
9-H
s
OCH
s
3
AB XY Spin System
6a
6b
6c
9.97
9.94
10.01
6.78 – 7.31
6.32 – 7.40
6.80 – 7.35
7.55
7.54
7.56
6.48
6.48
6.48
3.26/2.61
3.15/2.60
3.16/2.59
3.63
3.57
3.64
6.07
6.04
6.09
—-
3.51
—-
Table
6
13
C nmr Data of the Compounds 6a-c (δ Values in (CD ) SO, TMS as Internal Standard)
3 2
C-7 C-8 C-9 C-8a C-5
35.7 39.0 63.0 102.5 116.9 136.8 129.2 149.0 149.3
6b [a] 35.9 39.3 63.0 103.3 117.2 137.2 129.3 149.3 149.6
6c 35.6 39.2 63.2 102.5 117.2 137.0 129.9 149.3 149.6
C-6
C-4a C-3a C-2
o,m-C(Ar)
p-C(Ar)
i-C(Ar)
6a
124.6, 126.7, 126.8,
126.9, 127.2, 128.3
112.7, 124.9, 127.0,
127.5, 128.1, 128.6
124.9, 127.0, 127.1,
127.6, 128.6, 128.9
125.1, 126.8, 127.6
139.0, 139.3, 142.0
127.1, 127.9, 157.0
127.2, 128.0, 129.6
134.2, 139.3, 139.9
139.2, 139.7, 141.3
[a] OCH : δ = 54.8
3
Conclusion.
3-(4,7-Dihydro-5,7-diphenyl-1,2,4-triazolo[1,5-a]pyrimidin-6-
yl)-1,3-diphenyl-1-propanone (3a).
In contrast to earlier N-methylation reactions with CH I
3
This compound was obtained as colorless crystals: mp 222 –
224 °C; 58 % yield; ir (KBr): 3300 - 2700, 1692, 1652, 1596
or (CH O) SO [2,4,11], the reaction of 4,7-dihydro-5,7-
3
2
2
diphenyl-1,2,4-triazolo[1,5-a]pyrimidine (1) with the
enones 2a-f leads in an alkaline medium to alkylation at C-
6. This Michael type addition is followed by a cyclocon-
densation to 4,7,8,9-tetrahydro-1,2,4-triazolo[5,1-b]quina-
zolines (6a-c), provided that a methyl instead of a phenyl
group, is present at C-5 of the triazolopyrimidine ring sys-
tem [12].
-1
cm . The fd ms spectrum showed the molecular ion at m/z (%)
+
483 (100) [M + H] .
Anal. Calcd. for C
H N O (482.2): C, 79.64; H, 5.43; N,
32 26 4
11.61. Found: C, 79.85; H, 5.77; N, 11.94.
3-(4,7-Dihydro-5,7-diphenyl-1,2,4-triazolo[1,5-a]pyrimidin-6-
yl)-3-(4-methoxyphenyl)-1-phenyl-1-propanone (3b).
This compound was obtained as colorless crystals: mp 221 °C;
-1
yield 56 %; ir (KBr): 3350 – 2700, 1696, 1652, 1600 cm . The fd
EXPERIMENTAL
ms spectrum showed the molecular ion at m/z (%) 513 (100) [M
+
+ H] .
General.
Anal. Calcd. for C
H N O (512.2): C, 77.32; H, 5.51; N,
33 28 4 2
10.93. Found: C, 77.27; H, 5.42; N, 11.00.
Melting points were taken on a Kofler melting point apparatus
and are uncorrected. Ir spectra were obtained in potassium bro-
mide pellets with a Specord M 82 spectrograph. H and C nmr
spectra were recorded on a Bruker AM 400 spectrometer in
3-(4-Chlorophenyl)-3-(4,7-dihydro-5,7-diphenyl-1,2,4-tria-
zolo[1,5-a]pyrimidin-6-yl)-1-phenyl-1-propanone (3c).
1
13
This compound was obtained as colorless crystals: mp 229 °C;
(CD ) SO. Mass spectra were measured on a Finnigan MAT 95
spectrometer using the field desorption technique. Elemental
analyses were obtained using LECO CHNS-900 equipment.
3 2
-1
yield 68 %; ir (KBr): 3350 – 2650, 1684, 1652, 1596 cm . The fd
+
ms spectrum showed molecular ion at m/z (%) 517 (100) [M + H] .

Nov-Dec 2003
4,7-Dihydro-1,2,4-triazolo[1,5-a]pyrimidines
1085
Anal. Calcd. for C
10.84. Found: C, 74.27; H, 4.82; N, 10.79.
H
N ClO (517.0): C, 74.34; H, 4.87; N,
This compound was obtained as colorless crystals: mp 243
-245 °C; yield 42 %; ir (KBr): 3300 – 2650, 1608, 1544 cm .
32 25
4
-1
The fd ms spectrum showed the molecular ion at m/z (%) 433
(100) [M + H] .
3-(4,7-Dihydro-5,7-diphenyl-1,2,4-triazolo[1,5-a]pyrimidin-6-
yl)-3-(4-fluorophenyl)-1-phenyl-1-propanone (3d).
+
Anal. Calcd. for C
H N O (432.2): C, 77.75; H, 5.59; N,
28 24 4
This compound was obtained as colorless crystals: mp 250
-252 °C; yield 67 %; ir (KBr): 3350 – 2650, 1684, 1652,1596
12.95. Found: C, 77.74; H, 5.52; N, 12.80.
8-(4-Chlorophenyl)-4,7,8,9-tetrahydro-6,9-diphenyl-1,2,4-tria-
zolo[5,1-b]quinazoline (6c).
-1
cm . The fd ms spectrum showed the molecular ion at m/z (%)
+
501 (100) [M + H] .
Anal. Calcd. for C
11.19. Found: C, 76.66; H, 4.91; N, 10.98.
H
N FO (500.2): C, 76.78; H, 5.03, N,
This compound was obtained as colorless crystals: mp 252
-255 °C; yield 44 %; ir (KBr): 3300 – 2700, 1612, 1552 cm .
32 25
4
-1
The fd ms spectrum showed the molecular ion at m/z (%) 437
(100) [M + H] .
3-(4,7-Dihydro-5,7-diphenyl-1,2,4-triazolo[1,5-a]pyrimidin-6-
yl)-1-(4-methylphenyl)-3-phenyl-1-propanone (3e).
+
Anal. Calcd. for C
H N Cl (436.6): C, 74.22; H, 4.84; N,
27 21 4
This compound was obtained as colorless crystals: mp 251 °C;
12.82. Found: C, 74.14; H, 4.76; N, 12.81.
-1
yield 61 %; ir (KBr): 3350 – 2700, 1692, 1656, 1596 cm . The fd
X-Ray Diffraction Study of 3a.
ms spectrum showed the molecular ion at m/z (%) 497 (100) [M
+.
+ H]
The crystals of 3-(4,7-dihydro-5,7-diphenyl-1,2,4-triazolo[1,5-
Anal. Calcd. for C
H
N O (496.2): C, 79.81; H, 5.68; N,
a]pyrimidin-6-yl)-1,3-diphenyl-1-propanone (3a) C H N O
33 28
4
32 26 4
11.28. Found: C, 79.78; H, 5.56; N, 11.15.
•H O are monoclinic. We found at 293 K: a = 20.54(1), b =
2
3
10.460(4), c = 12.777(5), β = 94.01(4)°, V = 2738(2) Å , space
2-(4,7-Dihydro-5,7-diphenyl-1,2,4-triazolo[1,5-a]pyrimidin-6-
yl)-1,4-diphenyl-1,4-butanedione (3f).
3
-1
group P2 /c, Z = 8, d = 1.192 g/cm , µ = 0.075 mm , F(000) =
1
calc
1036. Intensity of 5114 reflections (4869 independent, R
=
int
This compound was obtained as colorless crystals: mp 230 –
0.083) was measured on an automatic four-circles Siemens P3/PC
diffractometer (graphite monochromated MoKα radiation, Θ/2 Θ
-
232 °C; yield 46 %; ir (KBr): 3350 – 2650, 1684, 1652, 1596 cm
1
. The fd ms spectrum showed the molecular ion at m/z (%) 511
scan, 2Θ
= 50 °). The structure was solved by the direct method
max
+
(100) [M + H] .
using the SHELXTL PLUS 5 package [13]. The profile analysis by
the PROFIT [14] program was applied in order to improve the
experimental quality. Position of hydrogen atoms were calculated
Anal. Calcd. for C
H N O (510.2): C, 77.63; H, 5.13; N,
33 26 4 2
10.97. Found: C, 77.59; H, 5.06; N, 10.93.
geometrically and refined by “riding” model with U = 1.2 U .
iso
eq
Cyclocondensation of 3-Amino-1,2,4-triazole (4) with Two
Equivalents of Chalcone (2a).
2
Full-matrix least-squares refinement against F in anisotropic
approximation using 4869 reflections was converged to R1 = 0.097
(for 1490 reflections with F > 4σ(F), wR2 = 0.378, S = 1.172.
A solution of 0.08 g (1.5 mmol) of sodium methoxide, 0.25 g
(3.0 mmol) of 3-amino-1,2,4-triazole (4) and 6.2 mmol of chal-
cone (2a) in 10 mL of methanol was refluxed for 4 h. After cool-
ing, the product 3a was isolated by filtration, washed with
methanol, dried and recrystallized from a mixture of methanol
and dimethylformamide (2:1). The yield amounted to 52 %.
REFERENCES AND NOTES
[1] G. Fisher, Adv. Heterocycl. Chem., 57, 81 (1993).
[2] S. M. Desenko, Chem. Heterocycl. Compd. (Engl. Transl.),
31, 125 (1994).
General Procedure for the Preparation of the Triazolo[5,1-
[3] O. Y. Borbulevych and O. V. Shishkin, J. Mol. Struct., 446, 11
(1998).
[4] S. M. Desenko, V. D. Orlov and V. V. Lipson, Khim.
Geterotsikl. Soedin., 1638 (1990); Chem. Heterocycl. Compd. (Engl.
Transl.), 26, 1362 (1990).
[5] N. S. Zefirov, V. A. Palyulin and E. E. Dashevskaya, J. Phys.
Org. Chem., 3, 147 (1990).
[6] V. D. Orlov, S. M. Desenko, K. A. Potekhin and Y. T.
Struchkov, Khim. Geterotsikl. Soedin., 229 (1988); Chem. Heterocycl.
Compd. (Engl. Transl.), 24, 192 (1988).
[7] O. V. Shishkin, S. M. Desenko, V. D. Orlov, S. V. Lindeman
and Y. T. Struchkov, Izv. Akad. Nauk SSSR Ser. Khim., 1394 (1994); Russ.
Chem. Bull., 43, 1320 (1994).
[8] Y. V. Zefirov and P. M. Zorky, Uspekhi Khimii, 58, 713
(1989); Russ. Chem. Rev., 58, 421 (1989).
[9] S. M. Desenko, V. D. Orlov, O. V. Shishkin, K. E. Barykin, S.
V. Lindeman and Y. T. Struchkov, Khim. Geterotsikl. Soedin., 1357
(1993); Chem. Heterocycl. Compd. (Engl. Transl.), 29, 1163 (1993).
[10] O. V. Shishkin, N. V. Getmansky, S. M. Desenko, V. D. Orlov,
S. V. Lindeman and Y. T. Struchkov, Izv. Akad. Nauk SSSR Ser. Khim.,
1912 (1993); Russ. Chem. Bull., 42, 1827 (1993).
[11] S. M. Desenko, V. D. Orlov, V. V. Lipson, O. V. Shishkin, S.
V. Lindeman and Y. T. Struchkov, Khim. Geterotsikl. Soedin., 1539
(1991); Chem. Heterocycl. Compd. (Engl. Transl.), 27, 1242 (1991).
b]quinazolines 6a-c.
A solution of 0.08 g (1.5 mmol) of sodium methoxide, 0.21 g
(1.0 mmol) of 4,7-dihydro-5-methyl-7-phenyl-1,2,4-triazolo[1,5-
a]pyrimidine (5) and 1.2 mmol of an α,β-unsaturated carbonyl
compound (2a-c) in 10 mL of methanol was refluxed for 5 – 10
min. After cooling, the products 6a-c were isolated by filtration,
washed with methanol, dried and recrystallized from a mixture of
methanol and dimethylformamide (2:1). The yields and melting
1
13
points are summarized in Figure 3. The H and C nmr spectral
data are shown in Tables 5 and 6.
4,7,8,9-Tetrahydro-6,8,9-triphenyl-1,2,4-triazolo[5,1-b]quinazo-
line (6a).
This compound was obtained as colorless crystals: mp 240 –
243 °C; yield 53 %; ir (KBr): 3300 – 2650, 1600, 1548 cm . The
-1
fd ms spectrum showed the molecular ion at m/z (%) 403 (100)
+
[M + H] .
Anal. Calcd. for C
13.93. Found: C, 80.54; H, 5.42; N, 13.87.
H N (402.2): C, 80.56; H, 5.51; N,
27 22 4
4,7,8,9-Tetrahydro-8-(4-methoxyphenyl)-6,9-diphenyl-1,2,4-tri-
azolo[5,1-b]quinazoline (6b).

1086
V. V. Lipson, I. V. Ignatenko, S. M. Desenko, S. V. Shishkina, O. V. Shishkin,
S. A. Komykhov, N. V. Logvinenko, V. D. Orlov, and H. Meier
Vol. 40
[12] See also G. Zigeuner, H. Brunnetti, H. Ziegler and M. Bayer,
Monatsh. Chem., 101, 1767 (1970).
diffraction data, Rev. 5.02, Siemens Analytical X-ray Instruments Inc.,
Germany, (1994).
[13] G. M. Sheldrick SHELXTL PLUS 5. PC Version. A system of
computer programs for the determination of crystal structure from X-ray
[14] V. A. Strel’tsov and V. E. Zavodnik, Kristallografiya, 34,
1369 (1989).