A simple and efficient eco-friendly chemical procedures were developed for the synthesis of series of tricyclic and tetarcyclic dihydropyrimidine derivatives in excellent yields via a one-pot, multi-component reaction in the presence of silica sulfuric acid / ethylene glycol catalyst. The Tricyclic dihydropyrimidine derivatives 1a-g (benzo[4,5]imidazo[1,2-a]pyrimidine derivatives) were synthesized in high yields and high purity with short reaction times by reacting 2-aminobenzimidazole, aldehydes and ethyl acetoacetate. Also, the tetracyclic dihydropyrimidine derivatives 3a-f (benzo[4,5]imidazo[1,2-a]pyrimido[4,5-d]pyrimidin-4(1H)-one derivatives) were synthesized by the reaction of 2-aminobenzimidazole, aldehydes and cyanoacetamide. This present new protocol offers shorter reaction time, high yields and low cost. This method provides much improved protocol over the existing methods.
Abdelazeem, N., Basyouni, W., Abbas, S., El-Bayouki, K., & El-kady, M. (2019). Silica sulfuric acid / ethylene glycol: An Efficient Eco-friendly Catalyst for One-pot Synthesis of Tricyclic and Tetarcyclic Dihydropyrimidine Derivatives.. Egyptian Journal of Chemistry, 62(12), 2265-2276. doi: 10.21608/ejchem.2019.13142.1827
MLA
Nagwa Abdelazeem; Wahid Basyouni; Samir Abbas; Khairy El-Bayouki; Mohamed El-kady. "Silica sulfuric acid / ethylene glycol: An Efficient Eco-friendly Catalyst for One-pot Synthesis of Tricyclic and Tetarcyclic Dihydropyrimidine Derivatives.". Egyptian Journal of Chemistry, 62, 12, 2019, 2265-2276. doi: 10.21608/ejchem.2019.13142.1827
HARVARD
Abdelazeem, N., Basyouni, W., Abbas, S., El-Bayouki, K., El-kady, M. (2019). 'Silica sulfuric acid / ethylene glycol: An Efficient Eco-friendly Catalyst for One-pot Synthesis of Tricyclic and Tetarcyclic Dihydropyrimidine Derivatives.', Egyptian Journal of Chemistry, 62(12), pp. 2265-2276. doi: 10.21608/ejchem.2019.13142.1827
VANCOUVER
Abdelazeem, N., Basyouni, W., Abbas, S., El-Bayouki, K., El-kady, M. Silica sulfuric acid / ethylene glycol: An Efficient Eco-friendly Catalyst for One-pot Synthesis of Tricyclic and Tetarcyclic Dihydropyrimidine Derivatives.. Egyptian Journal of Chemistry, 2019; 62(12): 2265-2276. doi: 10.21608/ejchem.2019.13142.1827