The triethyloxonium tetrafluoroborate/1,2-dimethoxyethane (TEO/DME) mixture is a versatile and cheap substitute for trimethyloxonium tetrafluoroborate in O-methylations of pyrrolin-2-ones, quinolones, acridones, and 1-oxo-β -carbolines. Undesired O-ethylation can be avoided by preincubation of triethyloxonium tetrafluoroborate and 1,2-dimethoxyethane for 1 h, prior to addition of the substrate. In the course of these investigations it was found that the structures assigned to the alkaloids taraxacine A and B are erroneous.
三乙氧基四
氟硼酸盐/
二甲氧基乙烷(T
EO/
DME)混合物是一种多功能且便宜的
三甲氧基四
氟硼酸盐在
吡咯烷-2-酮,
喹啉酮,乙酰
喹啉和1-氧代-β-咔啉的O-甲基化反应中的替代品。通过在加入底物之前将三乙氧基四
氟硼酸盐和
二甲氧基乙烷预先孵育1小时,可以避免不必要的O-乙基化。在这些研究中发现,分配给蒲公英碱A和B的结构是错误的。