Conversion of 2,4-dihydroxybenzaldehyde to 2-benzoyloxy-4-hydroxybenzaldehyde and structural characterization of both precursor and product

Abstract

2,4-Dihydroxybenzaldehyde can be acylated at the 2 position if the more reactive 4 position is first protected as the methylmethoxy ether. Deprotection permits isolation of 2-benzoyloxy-4-hydroxybenzaldehyde. 2,4-Dihydroxybenzaldehyde, C₇H₆O₃, crystallizes in P2₁/c, with a = 7.3762(6), b = 11.7455(9), c = 7.3149(6) Å, β = 90.533(2)°, Z = 4, and D _X = 1.448 g cm⁻³. The individual molecules are characterized by an intramolecular hydrogen bond. The molecules form sheets with additional intermolecular hydrogen bonds. 2-Benzoyloxy-4-hydroxybenzaldehyde, C₁₄H₁₀O₂, crystallizes in Pca2₁, with a = 24.2629(14), b = 3.8445(2), c = 12.3727(8) Å, Z = 4, and D _X = 1.394 g cm⁻³. The molecules consist of two planar halves twisted by 51.63(5)° about the ester linkage. Intermolecular hydrogen bonding joins the molecules into ribbons approximately parallel to c.