Facile access to 5H-thiazolo[2',3':2,3]imidazo[4,5-b]indole derivatives by two-fold Cu-catalysed C-N coupling reactions.

In four simple steps, a series of 5H-thiazolo[2',3':2,3]imidazo[4,5-b]indole and 11H-benzo[4',5']thiazolo[2',3':2,3]imidazo[4,5-b]indole derivatives were prepared with high yields. The key step in this procedure was demonstrated to be two-fold Cu-catalysed C-N coupling reactions of 5-bromo-6-(2-bromophenyl)imidazo[2,1-b]thiazole and 3-bromo-2-(2-bromophenyl)benzo[d]imidazo[2,1-b]thiazole with various amines.

Practical Synthesis of 1,4-Dihydropyridines on Heterogeneous Sulfonicmodified Silica (SBA-15-SO3H) Catalyst Under Mild Condition.

AIMS: Synthesis of 1,4-Dihydropyridines (1,4-DHP) using heterogeneous catalyst under mild condition. OBJECTIVE: Our objective is to explore new applications of non-metal heterogeneous catalysts in the synthesis of 1,4-DHP derivatives in a greener and more efficient approach. METHODS: A greener and more efficient method for the synthesis of 1,4-DHPs and an asymmetric 1,4-DHP (Felodipine drug) was successfully developed in high yields using a heterogeneous SBA- 15-SO3H catalyst. RESULTS: A series of symmetric 1,4-DHP and an asymmetric 1,4-DHP (Felodipine drug) were successfully prepared in high yields using a heterogeneous SBA-15-SO3H catalyst. CONCLUSION: The catalyst, SBA-15-SO3H, exhibited an efficient catalyst activity for the synthesis of 1,4-DHP derivatives in high yields from the aldehyde, ß-ketoester, and NH4OAc as a nitrogen source under mild conditions and short reaction time. Bronsted acid sites of this solid catalyst were figured out to play a key role in this transformation. Interestingly, our catalyst is air-stable and can be recycled at least 5 times without losing catalytic activity.

Study on the Synthesis of Chabazite Zeolites via Interzeolite Conversion of Faujasites.

The interzeolite conversion of faujasite (FAU-type) zeolites to chabazite (CHA-type) zeolite in the presence of N,N,N-trimethyladamantammonium and N,N,N-dimethylethylcyclohexylammonium cations was investigated over a large compositional range by carefully controlling the reaction mixture compositions. Highly crystalline CHA zeolites were also obtained by the transformation of several zeolite types including EMT, LTL, LEV, RTH, and MFI frameworks. The formation of CHA zeolite from FAU zeolite precursors was substantially faster than that from zeolite L with a similar composition. High-silica CHA zeolites were also produced successfully using a mixture of TMAda with a number of less expensive organic structure-directing agents. The CHA zeolite materials have been synthesized with high crystallinity and with a Si/Al ratio ranging from 5 to 140. Our data support the importance of structural similarity between the zeolite precursors, nucleation/crystallization processes, and the zeolite product in the interzeolite conversion compared to conventional amorphous aluminosilicate gels. Our synthetic methods could be used to prepare other 8-membered ring zeolites such as AEI and AFX frameworks, potential candidates for selective catalytic reduction of NOx, light olefin production, and CO2 abatement.