3,4-dihydro-2H-pyran → 2-Hydroxy-5-(tetrahydro-pyran-2-yloxy)-benzaldehyde

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Reaction Steps

A solution of 2,5-dihydroxy-benzaldehyde (152 mmol), 3,4-dihydro-2H-pyran (167 mmol) and a catalytic amount of pyridinium p-toluenesulfonate in CH2Cl2 (480 mL) was left overnight at room temperature. The organic phase was washed with 1 N Na7CO3 (aq) (3×100 mL) and dried (Na2SO4). Evaporation in vacuo gave the desired product as brown crystals that was used without further purification. 1H-NMR (CDCl3) δ 10.72 (s, 1H), 9.88 (s, 1H), 7.32-7.29 (m, 2H), 6.96 (d, 1H), 5.38 (bs, 1H), 3.99-3.91 (m, 1H), 3.69-3.64 (m, 1H), 2.06-1.63 (m, 6H).

Provenance & Evidence