The synthesis of some new N-[1-(2,5-dichlorophenyl)-5-methyl-1,2,3-triazol- 4-yl]-carbamic acid ester derivatives

Article abstract of DOI:10.1002/jccs.200300173

The synthesis of some new N-[1-(2,5-dichlorophenyl)-5-methyl-1,2,3-triazol- 4-yl]-carbamic acid ester derivatives are reported in this paper. The yielded products 6a-1 were confirmed by Elemental analyses, NMR, MS, and IR spectra.

Full text of DOI:10.1002/jccs.200300173

Journal of the Chinese Chemical Society, 2003, 50, 1209-1213
1209
The Synthesis of Some New
N-[1-(2,5-Dichlorophenyl)-5-methyl-1,2,3-triazol-4-yl]-carbamic Acid Ester
Derivatives
Heng-Shan Donga* (
Ji-Dong Cuib (
), Wei Jiaa (
),
) and Qing-Lian Wanga (
)
aNational Laboratory of Applied Organic Chemistry, Institute of Organic Chemistry, College of Chemistry and
Chemical Engineering, Lanzhou University, Lanzhou, Gansu 730000, P. R. China
bDepartment of Chemistry, Guansu Education College, Lanzhou, Gansu 730000, P. R. China
The synthesis of some new N-[1-(2,5-dichlorophenyl)-5-methyl-1,2,3-triazol-4-yl]-carbamic acid ester
derivatives are reported in this paper. The yielded products 6a-l were confirmed by Elemental analyses, NMR,
MS, and IR spectra.
Keywords: Synthesis; Carbamic acid ester; 1-(2,5-Dichlorophenyl)-5-methyl-1,2,3-triazole; Curtius
rearrangement; N-[1-(2,5-Dichlorophenyl)-5-methyl-1,2,3-triazol-4-yl]-carbamic acid ester
derivatives.
INTRODUCTION
CHN Corder MT-3 analyzer.
Thionyl chloride was redistilled. 1-(2,5-Dichlorophen-
yl)-5-methyl-1,2,3-triazol-4-carboxylic acid 3 was prepared
following condensation methods of 2,5-dichlorophenyl azide
with ethyl acetoacetate.1 A cold solution of sodium ethoxide
(0.3 mol. in 160 mL absolute ethanol) was added to the mix-
ture of ethyl acetoacetate (22 mL) and 2,5-dichlorophenyl
azide (about 0.15 mol.) at 0~5 °C. The mixture was heated
under reflux on a water-bath for 10 hr. Hot water (70 mL) was
added to the brownish product. The mixture was acidified
with concentrated hydrochloric acid. 1-(2,5-Dichlorophen-
yl)-5-methyl-1,2,3-triazol-4-carboxylic acid 3 was separated
and crystallized from water-ethanol. The yield of 3 is a white
crystalline solid, m.p. 155-156 °C, (66%). IR umax: 3430,
3089, 2952, 1695, 1571, 1488, 1440, 1243, 1067, 977.0 cm-1.
1H NMR (200 MHz, CDCl3) dH: 2.527 (s, 3H, CH3-), 7.503 (s,
1H, Ar-H), 7.587 (s, 2H, Ar-H), 12.210-12.315 (b, 1H,
-COOH) ppm. MS m/z (%): 271 (M , 4%), 256 (1), 242 (1),
227 (4), 214 (6), 209 (1), 208 (3), 198 (100), 182 (3), 180 (9),
172 (26), 164 (23), 147 (33), 145 (58), 136 (16), 128 (15), 111
(37), 109 (84), 100 (20), 83 (94), 75 (78), 63 (26).
Certain compounds having a 1,2,3-triazole nucleus
have been reported as antibacterial, fungicidal, antiviral,
anti-inflammatory and analgesic.1 Some carbamic acid esters
are very effective and wide-ranging bactericides, insecti-
fuges, herbicides in agriculture and also contend with medul-
lar and leucocytes pernicious tumors, have bacteriostatic
properties,2 are anticonvulsant,3 can treat Alzheimer’s dis-
ease (rivastigmine)4 and anti-HIV (human immunodefi-
ciency virus)5,6,7 in medicine. Recently some new 1,2,3-tri-
azole derivatives have been synthesized to inhibit tumor pro-
liferation, invasion, metastasis8 and are anti-HIV.9,10 For this
reason, synthesis of several compounds of N-[5-methyl-1-
(2,5-dichlorophenyl)-1,2,3-triazol-4-yl]-carbamic acid ester
derivatives that contain a 1,2,3-triazole nucleus in the mole-
cule are very interesting. The title compounds were prepared
according to the following method.
EXPERIMENTAL
All melting points are uncorrected and determined on
an XT4-100x microscopic melting point apparatus. IR spectra
were obtained in KBr discs on a Shimadzu IR-435 spectrome-
ter. MS were performed on a HP-5988A spectrometer (EI at
The preparation of 1-(2,5-dichlorophenyl)-5-methyl-
1,2,3-triazol-4-carbonyl chloride 4
Place a mixture of 49.14 g (30 mL, 0.413 mole) of
redistilled thionyl chloride and 11.4 g (0.042 mole) of com-
pound 3 in a 100 mL round bottomed flask, warm and stir the
mixture on a water bath for 2 hours. Reflux for 2 hours, distil
excessive thionyl chloride under reduced pressure and cool to
1
70 eV). H NMR spectroscopy (CDCl3) were recorded on
Avance DRX 200 NMR instrument with TMS as an internal
standard. Elemental analyses were carried out on a Yanaco

1210 J. Chin. Chem. Soc., Vol. 50, No. 6, 2003
Scheme I The synthesis route of the title compounds
Dong et al.
room temperature. A white solid is obtained and recrystal-
(100), 138 (11), 136 (34), 127 (8), 111 (34), 109 (92), 100
(29), 75 (56), 63 (19).
lized with absolute diethyl ether. The yield of 4 is a white
crystalline solid, m.p. 104-105 °C, 11.7 g (96%). IR umax
:
3067, 3089 (Ar-H), 1758 (C=O), 1584, 1487, 1456 (s, Ar),
1294 (C=N-N), 972.8 (w, -N-N=N-), 576.7, 539.1 (m, C-Cl)
General procedure of preparation of alkyl\aryl
N-[1-(2,5-dichlorophenyl)-5-methyl-1,2,3-triazol-4-yl]-
carbamic acid ester derivatives 6a-l
1
cm-1. H NMR dH: 7.591-7.585 (d, 2H, J = 1.2 Hz, Ph-H),
7.487 (s, 1H, Ph-H); 2.488 (s, 3H, CH3-) ppm. MS m/z (%):
289 (M , 12.5%), 295 (0.4), 293 (4), 291 (12), 263 (3), 261
(3), 256 (9), 254 (14), 228 (10), 226 (16), 220 (2), 200 (16),
198 (26), 190 (10), 188 (64), 186 (100), 174 (4), 172 (7), 163
(5), 147 (29), 145 (43), 136 (6), 128 (5), 111 (14), 109 (42),
100 (7), 75 (23), 74 (24), 67 (10).
A mixture of 1 mmole 1-(2,5-dichlorophenyl)-5-meth-
yl-1,2,3-triazol-4-carbonyl azide 5 and 100 mmole hydroxyl
group derivatives (ArOH or ROH) was heated under reflux
(range of 80~100 °C) until the compound 5 had disappeared.
After removal of excess hydroxyl group derivatives (6a-i
solvent for excess hydroxyl group derivatives, 6j, 6k, 6l sol-
vent for n-hexane), the reaction mixture was cooled and the
solid residue was separated by column chromatography
(CH3CO2CH2CH3: petroleum ether = 1:5) to afford 6a-l.
The preparation of 1-(2,5-dichlorophenyl)-5-methyl-
1,2,3-triazol-4-carbonyl azide 5
Stir a suspended mixture of 10.2 g (0.035 mole) com-
pound 4, 50 mL n-pentane and sodium azide 3.4 g (0.052
mole) in a 100 mL round bottomed flask until compound 4
has disappeared (track by TLC) at room temperature. The
suspended mixture was filtered and crude products were dis-
solved with acetone in order to remove less soluble impuri-
ties and then recrystallized. A white solid is obtained. The
yield of 5 is a white crystalline solid, m.p. 105-107 °C (de-
compound), 10.2 g (98%). IR umax: 3067, 3102 (Ar-H), 2136,
RESULTS AND DISCUSSION
The new alkyl\aryl N-[1-(2,5-dichlorophenyl)-5-meth-
yl-1,2,3-triazol-4-yl]-carbamic acid ester derivatives 6a-l
have been synthesized by the Curtius rearrangement of 5-
methyl-1-(2,5-dichlorophenyl)-1,2,3-triazol-4-carbonyl
azide 5 then the addition of its products isocyanates with vari-
ous hydroxyl group derivatives.11 The structure of these com-
pounds was characterized with 1H NMR, IR and MSspectros-
copy and results are given in Tables 2, 3 and 4. The IR spectra
data of compound 6a-l characteristic peaks at 3167, 3270 and
1696-1740 cm-1 could be found. These peaks could be as-
signed to NH and nC=O. The vibration bands of N-N=N were
in the region 968-978 cm-1 and C=N was in the region 1590-
O
C
O
2170 (m,
), 1689 (C=O), 1566, 1488
), 976.9 (-N-N=N-), 577.8
N
N
N
N
C
N
N
O
N
(Ar), 1262 (C=N-N), 1224 (
C
1
(C-Cl) cm-1. H NMR dH: 7.571-7.566 (d, 2H, J = 1.0 Hz,
Ph-H), 7.476 (s, 1H, Ph-H); 2.512 (s, 3H, -CH3) ppm. MS m/z
(%): 296 (M , 17%), 300 (2), 298 (11), 256 (3), 254 (7), 225
(7), 223 (8), 214 (25), 212 (37), 199 (35), 197 (49), 188 (46),
186 (72), 177 (24), 173 (56), 171 (90), 149 (25), 147 (64), 145

Synthesis of 1,2,3-Triazol-carbamic Acid Ester Derivatives
J. Chin. Chem. Soc., Vol. 50, No. 6, 2003 1211
Table 1. Structures, Yields and Melting Points of alkyl\aryl N-[1-(2,5-dichlorophenyl)-5-methyl-
1,2,3-triazol-4-yl]-carbamic Acid Ester Derivatives 6a-l
Compounda
R or Ar
Yield (%)
M.p.(°C) Time (h)
6a
6b
6c
6d
6e
6f
6g
6h
6i
-CH3
-C2H5
n-C3H7-
n-C4H9-
-C(CH3)3
-CH2CH2CH(CH3)2
white, spiculate crystal
white, spiculate crystal
white, spiculate crystal
white, spiculate crystal
white, granular crystal
white, granular crystal
white, spiculate crystal
white, spiculate crystal
white, granular crystal
white, granular crystal
white, granular crystal
white, granular crystal
96
97
98
95
43
95
85
78
72
66
62
76
176-178
152-153
161-162
147-148
165-166
131-132
168-169
150-151
170-171
178-180
142-143
166-167
30
24
6
4
4
4
4
4
4
-CH2C6H5
-CH2CH2OH
a-C10H7-
b-C10H7-
-C6H5
6j
6k
6l
4
4
4
a Satisfactory microanalyses were obtained for all the compounds.
Table 2. IR Spectral Data for Compounds 6a-l
Compound
IR (cm-1) (KBr disc)
6a
6b
6c
6d
6e
6f
6g
6h
6i
3385, 3223, 3144, 3008, 2961, 1741, 1606, 1587, 1500, 1459, 1252, 1098, 1083, 980.0, 826.6, 778.1, 579.4
3274, 3198, 3072, 2985, 2916, 1702, 1601, 1545, 1486, 1459, 1274, 1091, 1082, 967.2, 825.3, 774.4, 579.9
3286, 3200, 3069, 2969, 2931, 1707, 1607, 1537, 1489, 1458, 1274, 1091, 1082, 970.6, 819.4, 775.8, 577.4
3283, 3209, 3069, 2958, 2932, 1702, 1602, 1538, 1488, 1460, 1274, 1098, 1070, 969.5, 822.8, 771.4, 579.0
3331, 3244, 3078, 2983, 2934, 1712, 1605, 1527, 1491, 1457, 1276, 1255, 1097, 971.5, 829.9, 770.9, 578.7
3293, 3244, 3094, 2961, 2934, 1701, 1603, 1536, 1487, 1461, 1272, 1097, 1069, 971.1, 824.1, 768.5, 579.4
3309, 3209, 3079, 2958, 2935, 1707, 1604, 1534, 1491, 1452, 1255, 1097, 1061, 971.4, 802.9, 772.8, 578.1
3296, 3209, 3066, 2967, 2932, 1705, 1603, 1542, 1490, 1457, 1270, 1097, 1063, 971.6, 825.7, 767.0, 580.3
3466, 3272, 3209, 3074, 2962, 2932, 1705, 1604, 1542, 1488, 1460, 1282, 1094, 1057, 971.6, 823.6, 773.8, 579.9
3279, 3093, 3058, 2958, 2922, 1726, 1603, 1541, 1490, 1459, 1269, 1251, 1227, 1093, 1049, 970.2, 837.6, 774.5, 580.9
3287, 3209, 3057, 2958, 2923, 1725, 1607, 1547, 1488, 1461, 1265, 1245, 1215, 1099, 1030, 960.0, 810.4, 737.7, 580.2
3189, 3090, 2995, 2958, 2932, 1739, 1610, 1551, 1489, 1449, 1269, 1213, 1098, 1074, 973.7, 825.7, 730.2, 581.0
6j
6k
6l
Table 3. 1H NMR Spectral Data for Compounds
Compound
1H NMR (CDCl3-d) d(ppm), J (Hz) (CDCl3, TMS)
6a
6b
6c
7.527-7.481 (m, 3H, Ar), 6.965 (b, 1H, NH), 3.799 (s, 3H, -OCH3), 2.207 (s, 3H, CH3)
7.530-7.496 (m, 3H, Ar), 6.681 (b, 1H, NH), 4.297-4.190 (q, 2H, -OCH2-), 2.211 (s, 3H, CH3), 1.357-1.286 (t, 3H, CH3)
7.515-7.479 (m, 3H, Ar), 6.802 (b, 1H, NH), 4.161-4.094 (t, 2H, -OCH2-), 2.195 (s, 3H, CH3), 1.746-1.641 (m, 2H,
CH2), 0.996-0.922 (t, 3H, CH3)
6d
7.564-7.456 (m, 3H, Ar), 6.638 (b, 1H, NH), 4.217-4.151 (t, 2H, -OCH2-), 2.208 (s, 3H, CH3), 1.784-1.599 (m, 2H,
CH2), 1.539-1.359 (m, 2H, CH2), 0.979-0.917 (t, 3H, CH3)
6e
6f
7.516-7.467 (m, 3H, Ar), 6.587 (b, 1H, NH), 2.195 (s, 3H, CH3), 1.506 [s, 9H, -OC(CH3)3],
7.523-7.493 (m, 3H, Ar), 6.699 (b, 1H, NH), 4.241-4.174 (t, 2H, -OCH2-), 2.204 (s, 3H, CH3), 1.876-1.785 (m, 1H, CH),
1.615-1.550 (m, 2H, CH2), 0.952, 0.920 (2s, 6H, 2CH3)
6g
7.564-7.495 (m, 3H, Ar), 6.792 (b, 1H, NH), 4.755-4.714 (m, 1H, -OCH<), 2.201 (s, 3H, CH3), 2.035-1.734 (m, 4H, 2-
CH2-), 1.491-1.248 (m, 6H, -CH2CH2CH2-)
6h
6i
7.534-7.489 (m, 3H, Ar), 7.384 (s, 5H, -OC6H5), 7.090 (b, 1H, NH), 2.201 (s, 3H, CH3)
7.536-7.491 (m, 3H, Ar), 7.341 (b, 1H, NH), 4.356-4.311 (t, 2H, -OCH2-), 3.904-3.860 (t, 2H, HOCH2-), 2.222 (s, 3H,
CH3), 2.007 (b, 1H, -OH)
6j
6k
6l
8.040 (b, 1H, NH), 7.880-7.382 (m, 10H, Ar), 2.287 (s, 3H, CH3)
7.899-7.800 (m, 3H, Ar), 676 (b, 1H, NH), 7.537-7.336 (m, 7H, Ar), 2.280 (s, 3H, CH3)
7.545-7.204 (m, 8H, Ar), 7.292 (b, 1H, NH, disappear in D2O), 2.271 (s, 3H, CH3)
a All spectra were recorded at 297 K.

1212 J. Chin. Chem. Soc., Vol. 50, No. 6, 2003
Table 4. MS Spectral Data for Compounds 6a-l
Dong et al.
No
m/z (%)
M
6a
300(1.7) 302(1) 274(4) 272(6) 242(8) 240(12) 237(12) 217(9) 215(48) 213(74) 207(2) 205(6) 198((8) 196(15) 190(10)
188(65) 186(100) 174(18) 172(30) 151(6) 147(39) 145(62) 111(23) 109(64) 75(38) 74(38) 59(74)
314(2.5) 316(1.5) 299(1) 288(2) 271(2) 269(2) 254(3) 243(3) 241(5) 228(4) 226(5) 217(8) 215(41) 213(67) 200(15) 198(22)
190(12) 188(65) 186(100) 181(7) 179(20) 174(16) 172(27) 147(37) 145(54) 128(10) 111(24) 109(63) 75(39) 74(34)
328(1.3) 330(0.8) 313(1) 302(2) 300(3) 271(2) 269(2) 260(3) 258(4) 254(2) 243(2) 241(3) 228(3) 226(3) 217(4) 215(24)
213(34) 200(8) 198(11) 190(7) 188(37) 186(56) 181(5) 179(14) 174(9) 172(14) 147(19) 145(32) 128(6) 111(15)
109(35) 75(26) 74(18) 43(100)
6b
6c
6d
342(8.8) 344(1.5) 327(1) 316(4) 314(6) 296(2) 294(64) 280(4) 279(20) 260(8) 258(13) 254(3) 243(3) 241(5) 238(15) 228(5)
226(6) 221(24) 217(9) 215(36) 213(56) 205(10) 200(8) 198(13) 197(15) 190(17) 188(63) 186(100) 181(11) 179(37)
177(18) 174(13) 172(19) 163(16) 147(39) 145(59) 111(20) 109(49) 75(22) 74(19) 41(87)
6e
6f
342(0.4) 344(0.3) 271(4) 269(7) 260(3) 258(4) 242(2) 217(1) 216(5) 215(6) 214(9) 213(8) 199(2) 197(2) 190(2) 188(14)
186(21) 181(5) 179(15) 172(4) 147(9) 145(15) 111(6) 109(14) 75(7) 74(7) 57(100) 41(18)
356(0.7) 358(0.3) 341(1) 330(6) 328(9) 287(3) 271(4) 269(6) 260(16) 258(24) 217(9) 216(25) 215(39) 214(41) 213(55)
200(5) 198(6) 197(5) 190(9) 188(52) 186(81) 181(8) 179(24) 174(9) 172(14) 147(28) 145(43) 111(14) 109(34)
75(15) 74(13) 71(29) 55(16) 43(100)
6g
6h
6i
368(0.4) 370(0.3) 342(2) 340(3) 271(3) 260(15) 258(22) 242(2) 223(4) 216(14) 214(27) 205(5) 199(6) 197(7) 188(32)
186(47) 179(23) 147(15) 145(24) 111(8) 109(18) 83(100) 75(7) 74(6) 55(73) 41(20)
376(0.1) 257(1) 214(3) 212(5) 205(2) 199(2) 197(3) 188(12) 186(20) 177(2) 147(6) 145(9) 111(3) 109(8) 91(100) 79(8)
77(7) 75(4) 65(6)
330(0.3) 332(0.3) 302(1) 271(3) 269(5) 260(1) 258(2) 242(9) 240(11) 223(1) 215(28) 213(47) 205(20) 199(16) 197(24)
190(9) 188(52) 186(87) 179(35) 172(20) 147(41) 145(65) 136(8) 111(24) 109(51) 91(100) 75(32) 74(32) 63(19)
45(77)
6j
6k
6l
412(0.1) 368(1) 268(2) 239(1) 214(16) 212(25) 205(15) 199(9) 197(13) 190(2) 188(11) 186(17) 179(5) 177(14) 173(4)
171(7) 147(12) 145(29) 144(100) 127(2) 115(76) 111(9) 109(19) 75(13) 74(15) 63(12) 57(11)
412(0.1) 268(1) 214(10) 212(16) 205(10) 199(6) 197(9) 190(1) 188(7) 186(11) 179(3) 177(9) 173(3) 171(4) 147(8) 145(22)
144(100) 136(2) 127(1) 126(2) 115(44) 111(5) 109(12) 89(7) 75(9) 74(11) 63(9) 57(6)
362(0.1) 270(2) 268(3) 243(3) 241(4) 214(24) 212(38) 207(7) 205(22) 199(12) 197(19) 190(3) 188(20) 186(31) 179(7)
177(20) 173(5) 171(9) 147(19) 145(30) 136(5) 111(9) 109(26) 94(100) 77(8) 75(14) 74(17) 66(21) 65(17)
1680 cm-1.
sity Key Teacher by the Ministry of Education and Lanzhou
University NLAOC.
1
Comparing the H NMR spectra of 5 with 6a-l, we
could see that after the Curtius rearrangement to 6 the most
noticeable change is that the signals of amino protons at d
6.7-7.1 ppm appeared. The chemical shift of methyl group on
the triazole ring show in the range d 2.20-2.40 ppm, whereas
the aromatic protons resonate at d 7.27-7.86 ppm.
Received December 12, 2002.
We investigated the MS spectra of 6a-l and the results
showed that compounds 6a-l had weak molecular ion peak
and their base peak ions were 111 (4-Clphenyl), 57 (t-Bu),
144 (naphthyloxy). While analyzing the fragments to the sub-
sequent cleavage of the molecular ions, we found that the MS
spectra of 6a-l exhibited some important ion peaks at m/z
235, 205, 179 (11-75%), 163 (2-24%), 152 (9-97%), 138 (2-
24%).
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