Clean and Green Approach for Synthesis of Various Derivatives of [1,3]Oxazine in Sustainable Aqueous Hydrotropic Medium

Abstract

An efficient and sustainable synthesis of 2,3-dihydro-2-phenyl-1H-naphtho[1,2-e] [1,3]Oxazine and 3,4-dihydro-3-phenyl-2H-naphtho[2,1-e][1,3]oxazine derivatives has been achieved by the one-pot, multicomponent condensation of α- or β-naphthol (1 mmol), an aniline (1 mmol) and formaldehyde (2 mmol) using aq. 30% NaPTS hydrotropic solution at room temperature. The aqueous hydrotropic medium is nontoxic, reusable, inexpensive, and easily available. This improved strategy allows the very comfortable preparation of a wide variety of substituted [1,3]Oxazine derivatives under mild reaction conditions with a maximum yield of up to 92%, easy isolation of purified compounds, and an eco-friendly approach under sustainable development. This organic transformation shows a clean and green protocol for the synthesis of 2,3-dihydro-2-phenyl-1H-naphtho[1,2-e] [1,3]oxazine and 3,4-dihydro-3-phenyl-2H-naphtho[2,1-e][1,3]oxazine derivatives.