Synthesis of 6-Halo-1,2-Benzisoxazoles, Chromeno-6,7-Isoxazoles and Chromeno-6,7-Oxazoles

Synthesis of Fused Oxazolocoumarins from o‐Hydroxynitrocoumarins and Benzyl Alcohol Under Gold Nanoparticles or FeCl3 Catalysis

“…In the case of Method C, the 6‐benzylamino‐7‐hydroxycoumarin (7) was also isolated. The 7‐hydroxy‐4‐methyl‐6‐nitrocoumarin ( 5b ) reacted also with 1 (Scheme ) and gave the oxazolocoumarin 6b in good enough yields (Methods A,B) (Table , entries 7–9). In the cases of the reactions of 1 with the 7‐hydroxy‐8‐nitrocoumarins 8a,b , the products 9a,b received in better yields under Method B (Table , entries 10–16).…”

“…[71% yield (Method A), 57% yield (Method B) and 25% yield (Method C)] light yellow solid, mp 231–232 °C (MeOH) (lit. mp 232–233°C).…”

Benzofurans from Benzophenones and Dimethylacetamide: Copper‐Promoted Cascade Formation of Furan O1C2 and C2C3 Bonds Under Oxidative Conditions

“…[2] Moreover, it had nothing in common with the general entries to the benzofuran core, as an unprecedented simultaneous formation of the furan O1 À C2 and C2 À C3 bonds was involved. [3] Herein, we present the synthesis of a series of 3-arylbenzofurans and the progress made to gain a more profound knowledge of the possible pathways that could explain this novel entry to the benzofuran core. As an additional proof to support our proposal, an innovative cyclization of ortho-hydroxy-a-arylstyrenes is also presented.…”