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(TEO/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。