TY - JOUR
T1 - Improved enamine-type addition of dehydroaporphine using microwave irradiation
AU - Huang, Wei J.
AU - Huang, Chih Chiang
AU - Hsin, Ling W.
AU - Tsai, Yeun M.
AU - Lin, Chin Ting
AU - Lin, Jung Hsin
AU - Lee, Shoei Sheng
PY - 2010/6/9
Y1 - 2010/6/9
N2 - Previous report demonstrated that 7-substituted aporphine, possessing interesting biological aspects, could be synthesized via an enamine-type addition of dehydroaporphine reacted with an electrophile, but it has the drawbacks of a long reaction time, low yield, and limitation to reactive electrophiles. Here we found that the reaction time and yield could greatly be improved under microwave irradiation in the presence of 4 equiv of sodium iodide for the synthesis of 7-benzyl dehydroglaucine. The application of this finding for treating dehydroglaucine with a variety of alkyl bromides also gave corresponding 7-substituted dehydroglaucines (2a-j) with yields of 14-89%. Other enamines such as 1,10-dimethoxydehydroaporphine (3a), 2,9-diacetyldehydroboldine (3b), and 7,8-dihydroberberine (5) were found to react with benzyl bromide under similar conditions as described above to give corresponding products (4a-b, 6) in satisfactory yields, indicating the versatility of this improved reaction condition.
AB - Previous report demonstrated that 7-substituted aporphine, possessing interesting biological aspects, could be synthesized via an enamine-type addition of dehydroaporphine reacted with an electrophile, but it has the drawbacks of a long reaction time, low yield, and limitation to reactive electrophiles. Here we found that the reaction time and yield could greatly be improved under microwave irradiation in the presence of 4 equiv of sodium iodide for the synthesis of 7-benzyl dehydroglaucine. The application of this finding for treating dehydroglaucine with a variety of alkyl bromides also gave corresponding 7-substituted dehydroglaucines (2a-j) with yields of 14-89%. Other enamines such as 1,10-dimethoxydehydroaporphine (3a), 2,9-diacetyldehydroboldine (3b), and 7,8-dihydroberberine (5) were found to react with benzyl bromide under similar conditions as described above to give corresponding products (4a-b, 6) in satisfactory yields, indicating the versatility of this improved reaction condition.
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U2 - 10.1016/j.tetlet.2010.04.008
DO - 10.1016/j.tetlet.2010.04.008
M3 - Article
AN - SCOPUS:77953121326
SN - 0040-4039
VL - 51
SP - 3062
EP - 3064
JO - Tetrahedron Letters
JF - Tetrahedron Letters
IS - 23
ER -