Highly Chemoselective Condensation of β-Naphthol, Aldehyde, and Urea Catalyzed by Thiamine Hydrochloride

Abstract

A three-component condensation reaction involving β-naphthol, aldehyde, and urea in the presence of 10 mol% thiamine hydrochloride (VB₁) as a catalyst is described. Aromatic aldehydes bearing different functional groups exhibited different behavior than β-naphthol and urea under similar reaction conditions. A possible mechanism to account for the reaction is proposed.

Keywords:

• Catalysis
• chemoselective
• multicomponent reactions (MCRs)
• β-naphthol
• thiamine hydrochloride (VB₁)

ACKNOWLEDGMENTS

This work was supported by the Chinese National Science and Technology Major Project “Key New Drug Creation and Manufacturing Program” (Grants 2009ZX09301-001 and 2009ZX09102), the Chinese National High-Tech Research and Developed Program (Grant 2007AA02Z147), the National Natural Science Foundation of China (Grants 90713046, 30772638, and 30925040), and the CAS Foundation (Grant KSCX2-YW-R-179).

Notes

^a Conditions: β-naphthol 1a (5 mmol), aldehyde 2 (5 mmol), urea 3 (7.5 mmol), VB₁ (0.5 mmol), 150 °C for 30 min.

^b Isolated yield.

^a Conditions: β-naphthol 1 (5 mmol), aldehyde 2b or 2f (5 mmol), and urea 3 (7.5 mmol).

^b Isolated yields.

^a Conditions: β-naphthol 1a (10 mmol), aldehyde 2 (5 mmol), VB₁ (0.5 mmol), 150 °C for 30 min.

^b Isolated yields.