Efficient Microwave Synthesis of 2-substituted-3,5- dinitrothiophene Scaffolds and Survey of Their Hollow Microporous Nature

Background: Application of microwave irradiation to heterogeneous catalysis has not been explored intensively due to arching phenomena of metals-supported catalysts in presence of flammable solvents. Hence, solvent free organic microwave synthesis has attracted great interests because of high efficiency, shorter reaction times and eco-friendly nature. Methods: This is the report of an efficient and expeditious green protocol for SNAr reaction of 2- bromo-3, 5-dinitrothiophene with amines and thiophenols using microwave heating. The solvent-free, chromatography-free method is highly sustainable along with the recyclability point of the solid support simple neutral Al2O3. Results: Approximately 100% conversion takes place just only in 2-3 min under microwave irradiation at 40°C. Conclusion: Several N-substituted 3, 5-dinitrothiophene-2-amine and S-substituted 3, 5-dinitro-2-sulfanylthiophene derivatives have been synthesized with good to excellent yields within very short time in environmentally benign manner. The synthesized products show very interesting morphological feature (microporous tube) towards privileged nanotechnology. Another mentionable thing is that the products are fully organic microporous tubes whose synthesis is really challenging.