Ethyl 3-hydroxybenzo[b]furan-2-carboxylate

Molecules in the title compound, C11H10O4, occur as centrosymmetric dimers, which lie in parallel planes separated by about 1 Angstrom. Both intra- an d intermolecular hydrogen bonding occurs across the -OH ... O=C groups of t he dimer, in a rhombic arrangement. The non-H atoms are effectively planar in each monomeric unit, with the ethyl groups lying in an extended trans co nfiguration. A theoretical study of the equilibrium structures of both the monomeric and dimeric units was made by SCF (self-consistent field) methods with a double-zeta basis set. The monomeric and dimeric structures obtaine d are very similar to each other, and to the observed structure.