Synthesis of 3-(3-alkyl-5-thioxo-1H-4,5-dihydro-1,2,4-triazol-4-yl) aminocarbonylchromones

Article abstract of DOI:10.1023/B:COHC.0000037320.27881.27

A series of 3-(3-alkyl-5-thioxo-1H-4,5-dihydro-1,2,4-triazol-4-yl) aminocarbonylchromones has been prepared by oxidation of 3-formylchromone with Jones' reagent followed by reaction with 3-alkyl-4-amino-4,5-dihydro-1,2,4- triazole-5(1H)-thione in the presence of POCl³. The structures of the compounds were confirmed by IR, LC-MS, and ¹H NMR spectra and elemental analyses.

Full text of DOI:10.1023/B:COHC.0000037320.27881.27

Chemistry of Heterocyclic Compounds, Vol. 40, No. 5, 2004
SYNTHESIS OF 3-(3-ALKYL-5-THIOXO-
1
H-4,5-DIHYDRO-1,2,4-TRIAZOL-4-YL)-
AMINOCARBONYLCHROMONES
1
,2
1
1
Linghua Cao , Lin Zhang , and Pengyuan Cui
A series of 3-(3-alkyl-5-thioxo-1H-4,5-dihydro-1,2,4-triazol-4-yl)aminocarbonylchromones has been
prepared by oxidation of 3-formylchromone with Jones' reagent followed by reaction with 3-alkyl-4-
amino-4,5-dihydro-1,2,4-triazole-5(1H)-thione in the presence of POCl . The structures of the
3
1
compounds were confirmed by IR, LC-MS, and H NMR spectra and elemental analyses.
Keywords: 3-(3-alkyl-5-thioxo-1H-4,5-dihydro-1,2,4-triazol-4-yl)aminocarbonylchromones, 3-formyl-
chromone, synthesis.
Compounds of chromone series have received considerable attention in the life sciences owing to their
specific framework and their versatile and significant biological activities. In the study of modified chromones,
compounds with antitumor, antibacterial, antiviral, hypolipidemic, and hypoglycemic activities have been
discovered among 3-heterylsubstituted chromones [1]. 1,2,4-Triazoles are also reported to exhibit a broad
spectrum of biological activity [2-4]. A series of investigations on combining these components together showed
that the triazole-chromone systems formed display novel biological activities and could expand the scope of
antibiotics. It stimulated us to introduce the 3-alkyl-4-amino-5-thioxo-1H-4,5-dihydro-1,2,4-triazole (1)
fragment [5] into the parent chromone. The bioactivities of these compounds are under investigation.
Starting from o-hydroxyacetophenones 2 we obtained 3-formylchromones 3; the latter, through
oxidation with Jones' reagent [6], were transformed to 3-carboxychromones 4, which then reacted with 3-alkyl-
4
-amino-5-thioxo-1H-4,5-dihydro-1,2,4-triazoles in the presence of POCl to give the target compounds 5-28.
3
1
The structures of the compounds were characterized by elemental analyses, IR, LC-MS, and H NMR spectra.
The synthetic route is shown in Scheme 1.
In the synthesis of 3-formyl-substituted chromones reported by Nohara et al. [7], there were no
variations in the molar ratio of substituted o-hydroxyacetophenone–POCl –DMF. We studied several ratios of
3
the basic material to the reagents, such as 1:1:1, 1:3:3, 1:3:6, and 1:6:12. In the ratio 1:6:12, the yield of the
product was 80-90%, which is higher than the reported yields.
In the IR spectra, the absorption band of C=O of the carboxyl group of 3-carboxychromone appeared at
-
1
1
750, which is higher than 1734 cm of 2-carboxychromone. It was identical with that reported in [8].
1
In H NMR spectra, the signal of 2-H in chromones appears at 6-8 ppm [9]. The electron-acceptor
substituent at position 3 shifts this signal to a lower field. Therefore the H-2 signals in compounds 5-28 were
consequently obtained at 9.1±0.1 ppm.
_
_________________________________________________________________________________________
1
College of Chemistry and Chemical Engineering, Xinjiang University, Urumqi 830046, P. R. China;
2
e-mail: clhxj@xju.edu.cn. State Key Laboratory of Elemento-Organic Chemistry, Nankai University, Tianjin
3
00071, P. R. China. Published in Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 749-754, May, 2004.
Original article submitted July 16, 2002.
0
009-3122/04/4005-0635©2004 Plenum Publishing Corporation
635

Scheme 1
S
N
NH
reflux
3
R CO H + NH NHCNHNH
2
2
2
R3
N
S
NH2
a–f
1
R1
R1
OH
O
1
) DMF–POCl3
2
) H O
2
R2
R2
COMe
CHO
2
a–d
O
3
a–d
R1
O
Jones' reagent
R2
CO H
2
O
4
a–d
H
N
N
R1
R1
R3
S
O
O
NH2
O
O
S
O
NH
N
R2
POCl3
CO H
R2
2
CNHN
4
a–d
R3
1
5
–28
3
3
3
3
3
3
2
1
2
1
a R = Me, b R = Ph, c R = n-C
3
H
7
, d R = n-C
4
H
9
, e R = n-C
5
H
11, f R = CF ; 2-4 a R = R = H, b R = H, R = Me,
3
1
2
1
2
1
1
2
2
2
2
c R = H, R = Br, d R = R = Cl; 5-22 R = H, 23-28 R = Cl; 5-10 R = H, 11-16 R = Me, 17-22 R = Br, 23-28 R = Cl;
3
3
3
3
5
, 11, 17, 23 R = Me, 6, 12, 18, 24 R = Et, 7, 13, 19, 25 R = n-Pr, 8, 14, 20, 26 R = n-Bu,
3
3
9
5 3
, 15, 21, 27 R = n-C H11, 10, 16, 22, 28 R = CF
The proton signals of the CONH group in compounds 5-28 appeared at 10.2-11.5 ppm as broad singlets.
In the thiolactam group they were shifted to 13.6-14.5 ppm.
In the IR spectra of the products, the characteristic absorption band of C=O in pyrone appeared at 1620-
-
1
1
1
670 cm , and the IR spectra of compounds 5-28 displayed a broad band at 3000 (CONH, CSNH), and a band at
-
1
700 (C=O of CONH) or 1310 cm (C=S).
All the compounds 5-28 had strong molecular-ion peaks in the LC-MS spectra (the relative abundance
was >60% or even the base peak). The LC-MS spectra exhibited the peaks of retro-Diels–Alder cracking and the
+
[
M+Na-H] peak.
EXPERIMENTAL
Melting points were recorded on a Yanaco MP-S3 microscopic melting point apparatus and are
1
corrected. IR spectra were recorded on a Bruker FT-IR ERUINOX-55; FTS-40 (KBr pellets). H NMR spectra
were recorded on a Bruker AC-80 (80 MHz) spectrometer (TMS as internal standard, solvent CDCl or DMSO).
3
6
36

TABLE 1. Physical Constants of Compounds 5-28
Found, %
Com-
pound
Empirical
formula
——————
Calculated, %
Yield,
%
mp, °C
C
H
N
5
6
7
8
9
C
C
C
C
C
13
14
15
16
17
H
H
H
H
H
10
12
14
16
18
N
N
N
N
N
4
4
4
4
4
O
O
O
O
O
3
3
3
3
3
S
S
S
S
S
51.52
3.39
3.33
3.89
3.82
4.20
4.27
4.60
4.68
1.86
1.98
4.86
4.89
3.89
3.82
4.31
4.27
4.70
4.68
5.03
5.06
5.44
5.41
2.43
2.45
2.35
2.38
2.79
2.81
3.22
3.20
3.54
3.57
3.94
3.92
1.41
1.39
2.20
2.17
2.69
2.62
3.06
3.03
3.37
3.41
3.74
3.77
1.21
1.19
18.62
18.53
17.80
17.71
16.92
6.96
16.31
16.27
15.79
15.73
16.02
15.99
17.76
17.71
16.89
16.96
16.31
16.27
16.67
15.63
15.09
15.04
15.18
15.13
14.77
14.70
14.07
14.18
13.73
13.69
13.33
13.24
12.85
12.81
12.94
12.87
15.15
15.09
14.62
14.54
14.08
14.03
13.64
13.56
13.20
13.11
13.23
13.18
>300
>300
51
49
41
40
38
32
53
50
42
39
33
29
51
48
32
30
30
35
48
47
43
40
36
31
5
1.65
53.10
3.16
5
54.50
4.53
>300
5
55.89
5.80
289-291
247-248
241-243
>300
5
43.86
3.83
4
1
1
1
1
1
1
1
1
1
1
2
2
2
2
2
2
2
2
2
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
C
13
H
7
F
3
N
4
O
3
S
44.61
4.57
4
C
C
C
C
C
14
15
16
17
18
H
12
H
14
H
16
H
18
H
20
N
4
N
4
N
4
N
4
N
4
O
3
O
3
O
3
O
3
O
3
S
S
S
S
S
53.12
3.16
5
54.56
4.53
>300
5
55.89
5.80
276-278
>300
5
56.93
6.97
5
57.96
8.05
278-280
217-219
>300
5
C
14
H
19
F
3
N
4
O
3
S
45.38
5.41
4
C
13
H
9
BrN
4
O
3
S
40.90
0.96
4
C
C
C
C
14
H11BrN
H13BrN
H15BrN
H17BrN
4
4
4
4
O
O
O
O
3
S
S
S
S
42.51
2.55
>300
4
15
16
17
3
3
3
43.99
4.02
251-252
247-248
241-243
233-234
284-285
248-249
237-239
230-231
218-219
197-199
4
45.44
5.40
4
46.73
6.69
4
C
13
H
6
BrF
3
N
4
O
3
S
35.83
5.88
3
C
13
H
8
Cl
2
N
4
O
3
S
42.13
2.06
4
C
C
C
C
14
H10Cl
H12Cl
H14Cl
H16Cl
2
2
2
2
N
N
N
N
4
4
4
4
O
O
O
O
3
S
S
S
S
43.72
3.65
4
15
16
17
3
3
3
45.21
5.13
4
46.60
6.50
4
47.84
7.78
4
C
13
H
5
Cl
2
F
3
N
4
O
3
S
36.81
6.72
3
Elemental analysis were taken on a Perkin–Elmer 2400 CHN analyzer. TLC was carried out on precoated glass
plates of silica gel GF 254. The spots were visualized by exposure under UV light or by the coloration of iodine
vapor.
All reagents are analytically pure.
General Procedure for the Synthesis of 3-Alkyl-4-amino-4,5-dihydro-1,2,4-triazole-5(1H)-thione
[
5] 1a-f. Thiocarbohydrazide (3.18 g, 0.03 mol) and 0.04 mol of fatty acid were refluxed for 4 h. After that the
reaction mixture was distilled in vacuum and the nonreacted fatty acid was taken off. The crude product obtained
was recrystallized from EtOH or EtOH–H O; mean yield 76% with this reaction.
2
6
37

TABLE 2. Spectral data of compounds 5-28
IR
Com-
pound
1
Mass spectrum,
m/z (I, %)
spectrum,
H NMR spectrum, δ, ppm
-1
cm
1
2
3
4
+
5
1700,
2.20 (s, 3H, CH
H-6, H-7, H-8); 9.17 (s, 1H, H-2);
11.44 (s, 1H, CONH); 13.89 (br. s, 1H, CSNH)
3
); 7.57-8.29 (m, 4H, H-5,
325 [M+Na] (55),
+
1
1
616,
312
302 [M] (98), 173 (100),
145 (35), 121 (52)
+
6
7
8
9
1701,
1.07-2.37 (m, 5H, C
2
H
5
); 7.58-8.22 (m, 4H, H-5,
355 [M+K] (60),
+
1
621,
H-6, H-7, H-8); 9.12 (s, H-2); 11.44 (s, 1H, CONH); 316 [M] (90), 173 (100),
1
310
13.84 (br. s, 1H, CSNH)
145 (50), 121 (46)
+
1702,
1.06-2.50 (m, 7H, C ); 7.54-8.17 (m, 4H, H-5,
H-6, H-7, H-8); 9.15 (s, 1H, H-2);
11.42 (s, 1H, CONH); 13.86 (br. s, 1H, CSNH)
3
H
7
353 [M+Na] (58),
+
1
620,
330 [M] (92), 173 (100),
1
311
145 (35), 121 (42)
+
1700,
1.09-2.56 (m, 9H, C
H-6, H-7, H-8); 9.11 (s, 1H, H-2);
11.38 (s, 1H, CONH); 13.79 (br. s, 1H, CSNH)
4
H
9
); 7.58-8.25 (m, 4H, H-5,
367 [M+Na] (58),
+
1
1
624,
309
344 [M] (90), 173 (100),
145 (41), 121 (53)
+
1703,
1.12-2.64 (m, 11H, C
H-6, H-7, H-8); 9.15 (s,1H, H-2);
11.42 (s, 1H, CONH); 13.86 (br. s, 1H, CSNH)
5
H11); 7.54-8.17 (m, 4H, H-5,
397 [M+K] (60),
358 [M] (97), 173 (100),
145 (52), 121 (48)
+
1
1
617,
310
+
1
1
0
1
1701,
2.30 (s, 3H, CH
3
); 7.43-8.04 (m, 4H, H-5, H-6,
395 [M+K] (60),
+
1
1
618,
311
H-7, H-8); 9.06 (s, 1H, H-2); 10.63 (s, 1H, CONH); 356 [M] (100), 173 (90),
14.02 (br. s, 1H, CSNH)
145 (57), 121 (32)
+
1701,
2.19 (s, 3H, CH ); 2.48 (s, 3H, CH
3
3
);
339 [M+Na] (64),
+
1
1
621,
319
7.73-8.02 (m, 3H, H-5, H-7, H-8); 9.09 (s, 1H,
H-2); 11.45 (s, 1H, CONH); 13.61 (br. s, 1H,
CSNH)
1.08-2.40 (m, 8H, CH
H-5, H-7, H-8); 9.10 (s, 1H, H-2);
316 [M] (98), 187 (100),
159 (35), 135 (42)
+
1
2
1705,
3
, C
2
H
5
); 7.68-8.04 (m, 3H,
369 [M+K] (59),
330 [M] , (100), 187
+
1
1
620,
317
11.46 (s, 1H, CONH); 13.64 (br. s, 1H, CSNH)
(91),
1
59 (43), 135 (38)
+
1
1
1
1
1
3
4
5
6
7
1700,
1.03-2.35 (m, 10H, CH
H-5, H-7, H-8); 9.11 (s, 1H, H-2);
11.50 (s, 1H, CONH); 13.64 (br. s, 1H, CSNH)
3
, C
3
H
7
); 7.58-8.05 (m, 3H,
383 [M+K] (60),
344 [M] (100), 187 (93),
+
1
1
623,
315
159 (41), 135 (32)
+
1701,
1.01-2.35 (m, 12H, CH
3
, C
3
H
7
); 7.49-8.03 (m, 3H,
381 [M+Na] (57),
+
1
1
624,
310
H-5, H-7, H-8); 9.11 (s, 1H, H-2);
11.56 (s, 1H, CONH); 13.62 (br. s, 1H, CSNH)
358 [M] (94), 187 (100),
159 (36), 135 (40)
+
1702,
1.03-2.30 (m, 10H, CH
3
, C
3
H
7
); 7.51-8.09 (m, 3H,
411 [M+K] (60),
+
1
1
621,
310
H-5, H-7, H-8); 9.13 (s, 1H, H-2);
11.49 (s, 1H, CONH); 13.65 (br. s, 1H, CSNH)
372 [M] (100), 187 (90),
159 (42), 135 (50)
+
1701,
2.33 (s, 3H, CH
3
); 7.45-8.05 (m, 3H, H-5,
409 [M+K] (60),
+
1
1
617,
313
H-7, H-8); 9.07 (s, 1H, H-2); 10.67 (s, 1H, CONH); 370 [M] (100), 187 (83),
14.01 (br. s, 1H, CSNH)
159 (37), 135 (50)
+
1699,
2.23 (s, 3H, CH ); 7.70-8.35 (m, 3H, H-5,
3
405 [M+2+Na] (60),
+
1
1
637,
310
H-7, H-8); 9.13 (s, 1H, H-2); 11.33 (s, 1H, CONH); 403 [M+ Na] (57),
13.63 (br. s, 1H, CSNH)
+
382 [M+2] (100),
+
3
80 [M] (100)
+
1
1
2
2
8
9
0
1
1695,
0.96-2.67 (m, 5H, C
2
H
5
); 7.75-8.30 (m, 3H, H-5,
419 [M+2+Na] (60),
+
1
1
637,
303
H-7, H-8); 9.17 (s, 1H, H-2); 11.34 (s, 1H, CONH); 417 [M+ Na] (58),
13.62 (br. s, 1H, CSNH)
+
396 [M+2] (100),
+
3
94 [M] (100)
+
1701,
0.99-2.68 (m, 7H, C
3
H
7
); 7.73-8.31 (m, 3H, H-5,
419 [M+2+Na] (63),
+
1
1
625,
303
H-7, H-8); 9.15 (s, 1H, H-2); 11.30 (s, 1H, CONH); 417 [M+ Na] (58),
+
13.66 (br. s, 1H, CSNH)
0.98-2.66 (m, 9H, C ); 7.75-8.30 (m, 3H, H-5,
397 [M+2+H] (100),
+
3
95 [M+H] (80)
+
1702,
4
H
9
433 [M+2+Na] (60),
+
1
1
617,
315
H-7, H-8); 9.19 (s, 1H, H-2); 11.31 (s, 1H, CONH); 431 [M+ Na] (60),
+
13.64 (br. s, 1H, CSNH)
0.95-2.63 (m, 11H, C 11); 7.75-8.30 (m, 3H, H-5,
411 [M+2+H] (100),
+
4
09 [M+H] (100)
+
1700,
5
H
447 [M+2+Na] (60),
+
1
1
623,
313
H-7, H-8); 9.17 (s, 1H, H-2); 11.34 (s, 1H, CONH); 445 [M+ Na] (60),
13.62 (br. s, 1H, CSNH)
+
425 [M+2+H] (100),
+
4
23 [M+H] (100)
6
38

TABLE 2 (continued)
1
2
3
4
+
2
2
2
2
2
2
2
2
1701,
7.57-8.29 (m, 3H, H-5, H-7, H-8); 9.14 (s, 1H,
H-2); 11.36 (s, 1H, CONH); 13.69 (br. s, 1H,
CSNH)
459 [M+2+Na] (60),
+
1
1
622,
311
457 [M+ Na] (62),
437 [M+2+H] (100),
35 [M+H] (100)
+
+
4
+
3
4
5
6
7
8
1723,
2.31 (s, 3H, CH
3
); 7.51-8.01 (m, 2H, H-5, H-7);
413 [M+4+K] (100),
411 [M+2+K] (70),
409 [M+K] (12),
+
1
1
641,
357
9.06 (s, 1H, H-2);11.12 (s, 1H, CONH);
13.93 (br. s, 1H, CSNH)
+
+
3
70 [M] (75)
+
1722,
1.01-2.59 (m, 5H, C
2
H
5
); 7.78-8.31 (m, 2H, H-5,
427 [M+4+K] (100),
425 [M+2+K] (68),
423 [M+K] (11),
+
1
1
641,
356
H-7); 9.07 (s, 1H, H-2); 11.14 (s, 1H, CONH);
13.95 (br. s, 1H, CSNH)
+
+
3
84 [M (67)
+
1721,
0.99-2.55 (m, 7H, C
3
H
7
); 7.80-8.32 (m, 2H, H-5,
441 [M+4+K] (100),
439 [M+2+K] (70),
437 [M+K] (15),
+
1
1
643,
357
H-7); 9.04 (s, 1H, H-2); 11.17 (s, 1H, CONH);
13.91 (br. s, 1H, CSNH)
+
+
3
98 [M] (56)
+
1721,
1.00-2.58 (m, 5H, C
2
H
5
); 7.81-8.33 (m, 2H, H-5,
455 [M+4+K] (100),
453 [M+2+K] (66),
451 [M+K] (13),
+
1
1
647,
355
H-7); 9.09 (s, 1H, H-2); 11.19 (s, 1H, CONH);
13.90 (br. s, 1H, CSNH)
+
+
4
12 [M] (54)
+
1723,
0.97-2.49 (m, 11H, C
5
H11); 7.78-8.31 (m, 2H, H-5,
469 [M+4+K] (100),
467 [M+2+K] (72),
465 [M+K] (16),
+
1
1
646,
356
H-7); 9.07 (s, 1H, H-2); 11.14 (s, 1H, CONH);
13.95 (br. s, 1H, CSNH)
+
+
4
26 [M] (47)
+
1724,
7.57-8.29 (m, 2H, H-5, H-7); 9.17 (s, 1H, H-2);
11.44 (s, 1H, CONH); 13.89 (br. s, 1H, CSNH)
467 [M+4+K] (100),
465 [M+2+K] (71),
463 [M+K] (18),
+
1
1
645,
353
+
+
4
24 [M] (37)
Synthesis of 3-Formylchromones 3a-d. Phenol or substituted phenol (1 mol) was heated to melting,
and an equimolar quantity of acetyl chloride was slowly added under vigorously stirring. Light heating was
continued until HCl completely evolved. Then anhydrous AlCl (2 mol) was added in separate batches in an ice-
3
water bath. Then it was kept about 6-10 h in an oil bath (with phenol or 4-methylphenol the temperature was
maintained at 120 ± 2°C; with 4-bromophenol and 2,4-dichlorophenol – at 125-130°C). Then the material was
hydrolyzed by crushed ice. It was distilled with water vapor; the oil layer was extracted with CH Cl and dried
2
2
with anhydrous Na SO , and the solvent was removed under reduced pressure. The substituted
2
4
o-hydroxyacetophenone 2 was obtained. A solution of substituted o-hydroxyacetophenon 2 (0.1 mol) in
anhydrous DMF (93 ml) was placed in a flask, and freshly distilled POCl (0.6 mol) was added dropwise with
3
mechanical stirring in an ice-water bath; the color of the solution changed from yellow to orange. After that, it
was stirred for 12 h at room temperature. The reaction was monitored by TLC [ethyl acetate–petroleum ether
(
60-90°C)–acetic acid 50:50:3] to completion, and the mixture was decomposed by ice-water after the reaction
was completed. The resulting residue was collected by filtration, washed with water, and recrystallized from
ethanol–water. The 3-formyl-substituted chromones are listed below: 3-formylchromone (3a), yield 80%,
R 0.83, mp 151-152°C; 3-formyl-6-methylchromone (3b), yield 85%, R 0.74, mp 173-174°C (lit. [7]:
f
f
1
74-175°C); 6-bromo-3-formylchromone (3c), yield 90%, Rf 0.73, mp 189-192°C; 6,8-dichloro-3-
formylchromone (3d), yield 82%, R 0.80, mp 170-171°C.
f
General Procedure for the Synthesis of 3-Carboxychromones 4a-d. A solution of 3-formyl-
substituted chromone (17.2 mmol) in acetone (240 ml) was added dropwise to 8.5 ml of Jones' reagent in 30 min.
The temperature should be maintained at 10-15°C. The color of the solution turned into green, and the resinous
precipitate was separated. The solution was poured into the other flask and concentrated by reduced pressure to
1
/3 of initial volume. It was poured into water (500 ml) with stirring and allowed to stand for ~2 h.
6
39

The light yellow precipitate was filtered off, washed with water, then dried. The residue was recrystallized from
acetone (3-carboxy-6-methylchromone was recrystallized from benzene).
General Procedure for the Synthesis of 3-(3-Alkyl-5-thioxo-1H-4,5-dihydro-1,2,4-triazole-4-
yl)aminocarbonylchromones 5-28. Freshly distilled POCl (20 ml) was added with stirring to a mixture of
3
3
-carboxychromone 4a-d (2 mmol) and compounds 1a-f (2 mmol); the reaction was monitored by TLC [ethyl
acetate–petroleum ether (60-90°C)–acetic acid 50:50:3] to completion. It was poured into crushed ice, filtered,
washed with water, dried, and recrystallized from DMF–EtOH to yield compounds 5-28 (Tables 1 and 2).
This work was supported by the Natural Science Foundation (29962002) and the Nankai University
State Key Laboratory of Elemento-Organic Chemistry.
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