Microwave-promoted synthesis of chiral pyridinium salts
作者:Gustavo H.R. Viana、Itamar C. Santos、Rosemeire B. Alves、Laurent Gil、Christian Marazano、Rossimiriam P.F. Gil
DOI:10.1016/j.tetlet.2005.09.036
日期:2005.11
The synthesis of several chiralpyridiniumsalts via Zincke’s reaction can be easily accomplished by domestic microwave oven irradiation. Yield enhancements, reduction of reaction time, and less racemization were observed under microwave heating when compared to conventional heating in similar conditions.
Derivatives and reactions of glutaconaldehyde—XIII
作者:Jan Becher、Lars Finsen、Ib Winckelmann
DOI:10.1016/s0040-4020(01)88892-x
日期:1981.1
A number of nucleophilic ringopenings of 3-substituted pyridinium salts have been reinvestigated and summarized. The structure of the resulting stable glutaconaldehyde derivatives was investigated in detail by 1H NMR. It has been concluded that in general nucleophilic pyridinium ringopenings are highly regiospecific. In each case investigated to date a single product was isolated, as a result of
已经对3-取代的吡啶鎓盐的许多亲核开环进行了重新研究和总结。通过1 H NMR详细研究了所得稳定的戊二醛醛衍生物的结构。已经得出结论,通常亲核吡啶鎓开环是高度区域特异性的。迄今为止,在每种情况下,由于亲核试剂仅在一个吡啶α位上受到亲核试剂的攻击,都分离出了一种产物。OH离子是唯一的亲核试剂,攻击发生在吡啶C-2处,而较大的亲核试剂(例如胺和碳负离子)攻击发生在吡啶C-6处。对于多种3-取代的吡啶,例如3-甲基,3-甲氧基-,3-氰基-,3-氯吡啶,情况就是如此。
The Use of N,N-Dialkyltrimethylsilylamines in the Synthesis of Pentamethinium Salts
作者:Stanislav Böhm、Marek Kořínek、Markéta Rybáčková
DOI:10.1055/s-0028-1088036
日期:2009.4
N,N-Dialkyltrimethylsilylamines were used for the synthesis of a series of pentamethinium salts starting from 2,6-disubstituted or 2,4,6-trisubstituted pyrylium salts, N-substituted 5-aminopenta-2,4-dienals or N-substituted 5-aminopenta-2,4-dien-1-ones. The reactions proceed smoothly under mild conditions, furnishing the desired products in good yields.