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Title
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One-pot, sequential four-component synthesis of benzo[c]pyrano[3,2-a]phenazine, bis-benzo[c]pyrano[3,2-a]phenazine and oxospiro benzo [c]pyrano[3,2-a]phenazine derivatives using 1,4-diazabicyclo[2.2.2]octane (DABCO) as an efcient and reusable solid base catalyst
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Abstract
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Abstract 1,4-Diazabicyclo[2.2.2]octane (DABCO) has
been used as an ef?cient and reusable solid base catalyst
for the one-pot, two-step, four-component synthesis
of pyrano[3,2-a]phenazine derivatives by the condensation
reaction of 2-hydroxy-1,4-naphthoquinone, 1,2-diamines,
carbonyl compounds and alkylmalonates under conventional
heating as well as microwave irradiation. This procedure
has also been applied successfully for the synthesis
of novel bis- benzo[c]pyrano[3,2-a]phenazine and oxospiro
benzo[c]pyrano[3,2-a]phenazine derivatives. Using this procedure,
all the products were obtained in good to excellent
yields. The catalyst has been recovered and reused several
times without any loss of reactivity.
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