标题：One-pot synthesis of tetrahydrobenzo[b]pyran and dihydropyrano[c]chromene derivatives in aqueous media by using trisodium citrate as a green catalyst
摘要：Trisodium citrate, a natural non-toxic compound, is used as a catalyst for an efficient, rapid,one-pot synthesis of tetrahydrobenzo[b]pyrans and dihydropyrano[c]chromenes in moderateto excellent yields and under eco-friendly conditions. The catalyst is environmental benign,easy handling, non-toxic, stable in air, inexpensive and could be reused at least five cycleswithout losing its activities.
