Synthesis of New and Novel N-Protected 1-Aminoalkyl-2-naphthol Derivatives

Abstract

A series of three-component reactions has been carried out using HClO₄-SiO₂ as a versatile heterogeneous catalyst. A series of new and novel N-protected 1-aminoalkyl-2-naphthol derivatives have been prepared under thermal solvent-free reaction conditions. In all cases, the reaction conditions were very simple and high-yielding.

Keywords:

• Carbamate
• heterogeneous catalyst
• 2-naphthol
• N-protected 1-aminoalkyl-2-naphthol
• silica perchloric acid (HClO₄-SiO₂)

ACKNOWLEDGMENT

We are thankful to the Sistan and Baluchestan University Research Council for the partial support of this research.

Notes

^a 0.07 g of HClO₄-SiO₂ equal to 0.035 mmol of H⁺, and the molar ratio of the catalyst to substrate is 3.5 mol%.

^b Yields refer to the isolated pure product, and the molar ratio of benzaldehyde/ 2-naphthol/methyl carbamate is 1/1/1.2.

^a Yields refer to the isolated pure products; the reaction was carried out under thermal solvent-free conditions in an oil bath at 85°C. The molar ratio of aldehydes/2-naphthol/methyl or benzyl carbamate/catalyst was 1/1/1.2/0.035.

^b Isolated yields after five catalyst recoveries.