Crosss-conjugated and Pseudo-Cross-conjugated Mesomeric Betaines, 19. Cycloaddition Products from Mesomeric Pyrimidiniumolates and TCNE and Their Thermal Ring Transformation Reaction
作者:Thomas Kappe、Wolfgang Lube、Kurt Thonhofer、Christph Kratky、Ulrike G. Wagner
DOI:10.3987/com-94-s56
日期:——
The bicyclic pyrido-pyrimidine mesoion (2) reacts with TCNE under the loss of HCN to yield the tricyanovinylated derivative (3). However, monocyclic pyrimidine betaines (4a-d) (substituted at C-5) afford with TCNE 1,4-dipolar cycloaddition products (5a-d). Compounds (5c,d) (with CH2 groups at the malonyl moiety) rearrange above 200 OC under the loss of HCN and phenyl isocyanate to yield cyclo-penta[d]pyrimidines (6a,b).
Synthesis, X-ray Structure, and Properties of a Tetrabenzannelated 1,2,4,5-Cyclophane
作者:Michael Brettreich、Michael Bendikov、Sterling Chaffins、Dmitrii F. Perepichka、Olivier Dautel、Hieu Duong、Roger Helgeson、Fred Wudl