Effect of Internal Hydrogen Bonding on BaseCatalyzed NH ProtonExchange Reactions of Isomeric Enamines

Pyridine-Mediated S-Vinylation of the Mercapto Group in Heterocyclic Compounds

“…[11][12][13] Thus, the 1 H NMR spectrum of each isolated product 3a-f exhibited a vinylic proton signal at about 6.90-7.11 ppm, which is in agreement with the (Z) configuration for the vinyl moiety.…”

Solvent-free synthesis of polysubstituted pyrroles catalyzed by ZnO nanorods

“…This conversion involves the initial reaction of primary amine 1 with dialkyl acetylenedicarboxylate 2 to form the desired enaminone 6 [36][37][38][39], and then 2-chloro-1,3-dicarbonyl 3 could be activated by ZnONRs and undergo the nucleophilic alkylation to produce intermediate 7. acetylenic compound 2 and a-chloroketone 3 and O 2-site of ZnO nanostructures taking up a proton of 9 to generate 4 (Scheme 2) [42]. The reusability of the catalyst was tested in the synthesis of pyrrole (4f) as shown in Fig.…”

Triphenylphosphine catalyzed vinyl amination: A mild, chemospecific and general vinyl amide synthesis

“…As was shown in Table 2, vinyl amides are the single products of the reactions. The assignment of the E and Z configurations of the products are based on the chemical shifts of vinylic protons, as the vinylic protons of the Z isomer appears at lower field as a result of anisotropic deshielding of the ester carbonyl groups 15 . It was shown in our previous work that the chemical shift of vinylic proton in the Z isomer is 6.94 ppm and it is 7.04 for the E isomer 16 .…”