Synthesis of 3H-1,5-benzodiazepine Using Heteropolyacids
J. Chin. Chem. Soc., Vol. 55, No. 4, 2008 845
solvent was evaporated to dryness. The residue was sub-
jected to column chromatography over silica gel to afford
pure 3H-1,5-benzodiazepine. The products are identified
by comparison of their physical and spectral data with those
of authentic samples. The recoverd catalyst was washed
with diethyl ether and can be reused. All products gave sat-
isfactory spectral data in accordance with the assigned
structures.
in the synthesis of 3H-1,5-benzodiazepine derivatives after
five times is reported. As is shown in Table 4, the yields of
reactions after using H14[NaP5W30O110] for five times show
a slight reduction. Therefore we concluded that the catalyst
sites were not poisoned by un-reacted reagents.
Received June 14, 2007.
Spectral data for selected products
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1
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Yield%a (after five times of recycling)
Entry R¢
R
First second third fourth fifth
1
2
3
4
5
6
H
CH3
CH3
CH3
CH3
C6H5
98
98
80
63
59
65
97
96
95.5
93.5
72.7
58.2
55.8
60.6
93.2
90.8
71.2
57.3
53.4
59.3
CH3
NO2
CH3
H
96.3
78.6
61.2
58.2
63.6
94.9
75.2
60.5
57.5
62.2
22. Bamoharram, F. F.; Hravi, M. M.; Roshani, M.; Jahangir, M.;
Gharib, A. J. Appl. Catal. A: Gen.l 2006, 302, 42-47.
23. Romanelli, G.; Autino, J. C.; Baronetti, G.; Thomas, H. Mol-
ecules 2001, 6, 1006-1011.
CH3 C6H5
a Yields were analyzed by GC.