Reaction of 2-(trifluoromethyl)chromones with pyridoxal: Formation of 1-benzopyranooxepino- and 1-benzopyranopyranopyridines

A detailed experimental and theoretical study of two novel substituted trifluoromethylchromones. The influence of the bulky bromine atom on the crystal packing

“…One of the most employed methods for the synthesis of chromones involves the reaction of ortho-hydroxyacetophenones with several acid anhydrides, followed by intra-molecular cyclization and subsequent dehydration [15][16][17][18]. The preparation of new 2-trifluoromethylchromones using the above method with trifluoroacetic ethyl ester has been reported by Sosnovskikh's group [19][20][21][22]. More recently, a new chemical pathway involving esterification and cyclization in one step using trifluoroacetic anhydride was developed in our laboratory [23].…”