A Facile Total Synthesis of Neurotrophic Metabolite (+/-)-Neuchromenin

Recent advances in the synthesis of 4H-chromen-4-ones (2012 − 2021)

“…Chromone 1 was prepared by condensation of the 2 0 -hydroxyacetophenone with ethyl formate in the presence of sodium hydride in THF followed by dehydration of the resulting chroman-3-ol with p-toluenesulfonic acid (PTSA) in refluxing benzene (Scheme 1). 46 The condensation of 2 0 -hydroxy-4 0 -methoxyacetophenone with ethyl methanoate in the presence of sodium in diethyl ether followed by acidification in the presence of concentrated hydrochloric acid and acetic acid, Scheme 1 in refluxing conditions, provided 7-methoxy-4H-chromen-4-one in good overall yield. 47 Similarly, condensation of the 2 0 ,6 0 -dihydroxyacetophenone with ethyl formate in the presence of sodium ethoxide followed by acidification led to the synthesis of 5-hydroxychromone in excellent yield, on decagram scale.…”