Molecules (2019)
Update date:2022-08-11
Topics:
Balá?, Matej
Kudli?ková, Zuzana
Vilková, Mária
Imrich, Ján
Balá?ová, L'udmila
Daneu, Nina
Performing solution-phase oximation reactions with hydroxylamine hydrochloride (NH2OH·HCl) carries significant risk, especially in aqueous solutions. In the present study, four N-substituted indole-3-carboxaldehyde oximes were prepared from the corresponding aldehydes by solvent-free reaction with NH2OH·HCl and a base (NaOH or Na2CO3) using a mechanochemical approach, thus minimizing the possible risk. In all cases, the conversion to oximes was almost complete. The focus of this work is on 1-methoxyindole-3-carboxaldehyde oxime, a key intermediate in the production of indole phytoalexins with useful antimicrobial properties. Under optimized conditions, it was possible to reach almost 95% yield after 20 min of milling. Moreover, for the products containing electron-donating substituents (-CH3, -OCH3), the isomerization from the oxime anti to syn isomer under acidic conditions was discovered. For the 1-methoxy analog, the acidic isomerization of pure isomers in solution resulted in the formation of anti isomer, whereas the prevalence of syn isomer was observed in solid state. From NMR data the syn and anti structures of produced oximes were elucidated. This work shows an interesting and possibly scalable alternative to classical synthesis and underlines environmentally friendly and sustainable character of mechanochemistry.
View MoreGuangzhou Flower's Song Fine Chemical CO,. Ltd
Contact:+86-20-87475199
Address:No.12, Fenghuang 3 Road, Jiulong Industrial Park, Luogang District, Guangzhou. China
Contact:021-61840961 021-61840962
Address:No.157,Zhuguang Rd, Qingpu, Shanghai, China
Jinan Jinguilin Chemical Co.,Ltd
Contact:+86-531-81188412
Address:3rd floor of Torch Building, Huanyuan Rd, City of Jinan
ZhangJiaGang YaRui Chemical Co.,Ltd.
Contact:0512-58360968
Address:China JiangSu Province Zhang Jia Gang City YangShe Oriental Plaza Building 10 B307
Anhui Gusheng Import&Export CO.,LTD
Contact:86-551-63662296
Address:Jinzhai Road NO.162 ,hefei, china
Doi:10.1002/ejic.201601371
(2017)Doi:10.1021/ja408704u
(2013)Doi:10.1016/S0040-4020(01)00062-X
(2001)Doi:10.1021/jo952172y
(1996)Doi:10.1055/s-2007-991095
(2007)Doi:10.1016/S0040-4039(00)92358-X
(1991)