e.g. Filippa Pettersson or Cancer Res. 75(6) , 1102-12, (2015) or 10.1002/anie.201600521
Synthesis of N-substituted 4-(2-oxoalkyl)-1, 4-dihydronicotinates and their inverse electron demand Diels-Alder reaction with 3, 4-dichlorothiophene 1, 1-dioxide
(Danishefsky's dieneg) at 100" C for 7 h in toluene. However, when 4g was heated with 2 equiv of 3, 4-dichlorothiophene 1, l-dioxide (7)'O in refluxng toluene for 12 h, a rather complex mixture was obtaizled from which the expected adduct 8g was isolated in 15% yield. Other products included recovered 4g (4%), the dimer of 7, and methyl nicotinate (1, 36%), probably formed by the decomposition of 4g. The fact that 8g was obtained ...