An efficient, multicomponent, green protocol to access 4, 7-dihydrotetrazolo [1, 5-a] pyrimidines and 5,6,7,9-tetrahydrotetrazolo[5,1-b]quinazolin-8(4H)-ones using PEG-400 under microwave irradiation

Dihydroazolopyrimidines: Past, Present and Perspectives in Synthesis, Green Chemistry and Drug Discovery

“…Firoj Basha et al. published [177] microwave assisted three‐component reaction of 5‐aminotetrazole 73 , aldehydes 32 and active methylene compounds in polyethylene glycol (PEG‐400) at 110 °C for 30 min. Several CH‐acids such as alkyl acetoacetates 27 and cyclohexane‐1,3‐diones 33,34 were used for the synthesis of various dihydrotetrazolo[1,5 ‐a ]pyrimidines 76 and 77 (Scheme 33).…”

“…A large number of articles deal with multicomponent reactions of 5-aminotetrazole with aldehydes and 1,3-diketones using non-classical methods of activation and various catalysts. Firoj Basha et al published [177] microwave assisted threecomponent reaction of 5-aminotetrazole 73, aldehydes 32 and active methylene compounds in polyethylene glycol (PEG-400) at 110 °C for 30 min. Several CH-acids such as alkyl acetoacetates 27 and cyclohexane-1,3-diones 33,34 were used for the synthesis of various dihydrotetrazolo[1,5-a]pyrimidines 76 and 77 (Scheme 33).…”

Recent Advances in the Multicomponent Synthesis of Heterocycles Using 5-Aminotetrazole

“…This method offers several advantages, including a green protocol, simplicity of operation, high yields, recyclability of the solvent, and isolation of the final product without the need for column purification. 95 Keshavarz and Taib developed a new, convenient, and significant domino synthetic protocol to synthesize 6,6-dimethyl-9-aryl-5,6,7,9-tetrahydrotetrazolo[5,1-b]quinazolin-8(4H)-ones 5 and ethyl 7-aryl-4,7-dihydrotetrazolo[1,5-a]pyrimidine-6-carboxylates 8 with high yield using arylaldehyde 2, 5-aminotetrazole (1), and an active methylene compounds 3 or 7, respectively, in a solventfree multicomponent protocol (Scheme 4). 96 Here new organic-inorganic Brønsted acidic ionic solids (BAISs) are prepared as catalysts utilizing the click reaction.…”

Multicomponent reaction (MCR) for constructing bis-spirocyclohexane skeletons using β-nitrostyrene derived MBH acetates, 1,3-indanedione and aldehydes via [1 + 1 + 1 + 3] annulation

“…The development of novel synthetic strategies for constructing new chiral spirocyclic compounds with varied medicinal potentials is a great challenge in organic and pharmaceutical chemistry. 1 In this regard, Multicomponent Reactions (MCRs) 2 are preferred for the synthesis of chiral spirocyclic compounds 3 by virtue of their advantages, i.e. , one-pot synthesis, avoiding isolation of intermediates and atom economy.…”