Theophylline as the catalyst for the diastereoselective synthesis of trans-1,2-dihydrobenzo[a]furo[2,3-c]phenazines in water

Abstract

Theophylline-catalyzed efficient and environmentally benign procedure for the diastereoselective synthesis of trans-1,2-dihydrobenzo[a]furo[2,3-c]phenazines with pyridinium ylide assisted domino reaction in water.

Green synthesis of novel pyrazolo‐fused benzophenazines using H3PW12O40 as efficient and recyclable catalyst under microwave irradiation

“…Considering the significant potential of novel pyrazole and benzophenazine derivatives as a source of valuable drug candidates, together with our continued interest on MCRs and our ongoing program for the synthesis of a wide range of complex organic compounds based on green chemistry protocols, here we report a green and efficient method for the synthesis of novel 11 H ‐benzo[ a ]pyrazolo[3,4‐ c ]phenazines ( 6) through a single‐pot multicomponent condensation reaction between 2‐hydroxy‐1,4‐naphthoquinone ( 1 ), o ‐phenylenediamine ( 2 ), aromatic aldehydes ( 4 ), and 4‐methylbenzenesulfonohydrazide ( 5 ) catalyzed by phosphotungstic acid (H 3 PW 12 O 40 ) as a highly efficient, eco‐friendly, and recyclable solid heteropolyacid catalyst under microwave irradiation (MWI) (180 W, max. 70 °C) in EtOH (Scheme ).…”

H3PW12O40@nano‐ZnO: An efficient, recyclable, and eco‐friendly catalyst for the green synthesis of novel benzo[a]pyrimido[5′,4′:5,6]pyrano[2,3‐c]phenazines via sequential multicomponent reactions under microwave irradiation

“…Because of our interest in the synthesis of benzophenazine derivatives, and as part of our research on the development of environmentally friendly methods for synthesis of heterocyclic compounds using reusable catalysts, we report here our results from the green synthesis of novel benzo[ a ]pyrimido[5′,4′:5,6]pyrano[2,3‐ c ]phenazines ( 6a–i ) by a single‐pot, domino, four‐component condensation reaction between 2‐hydroxy‐1,4‐naphthoquinone ( 1) , o ‐phenylenediamine ( 2) , benzaldehydes ( 4) , and barbituric acid ( 5) catalyzed by H 3 PW 12 O 40 @nano‐ZnO as a highly efficient, eco‐friendly, and recyclable heterogeneous catalyst under MWI (180 W, max. 70 °C) in EtOH (Scheme ).…”

One-pot synthesis of benzopyranophenazines using graphene oxide dichlorotriazine (GO-DCT) under microwave irradiations

“…Therefore, seeking e cient and economical methods for the preparation of phenazines through multicomponent reactions (MCRs) is a valuable area of research in organic and medicinal chemistry. Recently, reports have been developed on synthesis of phenazines using p-TSA [11], glacial acetic acid [12], 1,4-diazabicyclo[2.2.2]octane (DABCO), [13,14], thiourea-based organocatalysts [15], ca eine [16], theophylline [17], L-proline [18], 1-butyl-3-methylimidazolium hydroxide ([Bmim]OH) [19], Et 3 N [20], pyridine [21], and oxalic acid [22]. However, some of the reported methods su er from drawbacks including long reaction times, generating a large amount of waste, unpleasant reaction conditions, use of toxic, and non-reusable catalyst.…”