An efficient one-pot strategies for the synthesis of [1,3] oxazine derivatives

Abstract

Sodium hydrogen sulphate (NaHSO4), n-tetra butyl ammonium bromide (TBAB) as a phase transfer catalyst (PTC) in water, and 1-butyl-3-methyl imidazolium hydrogen sulphate [bmim]HSO4 as ionic liquid (IL) has been used as a mild reaction promoter for the cyclocondensation of formalin, β-naphthol and aromatic amines to afford respective 2,3-dihydro-2-phenyl- 1H-naphtho-[1,2-e] [1,3] oxazine derivatives. The present protocols are greener, high yielding and involved the nonchromatographic isolation procedure.