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(Table-1, No- 6). Next reaction temperature (Table-1, No-8-9) was investigated.
Decrease of the reaction temperature resulted in lover yield (Table-1, No-9). Then the
examination the catalyst effect on a reaction (Table-1, No-7-13) was done. However
replacement of Cu(Oac)2 with CuSO4 resulted in lower yield (Table-1, No-11). While
in case of Cu Powder (200 mesh) used only traces amount of desire product observed
(Table-1, No-13). Moreover it was observed that the catalyst was mandatory for
successfully performing the reaction, as no product was formed in the absence of the
catalyst (Table-1, No-12). Finally optimum reaction conditions were achieved when a
mixture of hydroxy salt, 1.2 equiv of phenyl acetylene, 5 mol % of Cu(Oac)2 in 1 ml
of Ethenol : water (4: 1) was irradiated for 2 min at a ceiling temperature of 100 o C
applying a maximum power of 36 W, affording the desired compound in 90 % yield
(Table 1 No-8). The protocol was checked with conventional condition providing
lower yield of 24 % of after 24 hrs.
N
N N
Ph OH
N3 One-Pot microwave-assisted
Cu salt (mol %)
Br
3
N2H4 (equiv.)
Ph (1.2 equiv.)
EtOH : Water (4:1, 1ml)
Ph
No.
time
(min)
N
N
H
NH
5
N N
N
temp ( o C) Cu salt (mol %) yield (%) b
1 c 20 100 °C Cu(Oac)2, 10 51
2 d 20 100 °C Cu(Oac)2, 10 84
3 20 100 °C Cu(Oac)2, 10 86
4 10 100 °C Cu(Oac)2, 10 80
5 5 100 °C Cu(Oac)2, 10 90
6 2 100 °C Cu(Oac)2, 10 90
7 1 100 °C Cu(Oac)2, 10 53
8 2 100 °C Cu(Oac)2, 5 90
9 2 90 °C Cu(Oac)2, 5 73
10 2 100 °C Cu(Oac)2, 2 57
11 2 100 °C CuSO4.5H2O, 5 67
Ph