Crystal structures of 2-acetyl-4-ethynylphenol and 2-acetyl-4-(3-hy­droxy-3-methylbut-1-yn-1-yl)phenol

In the title compounds, C(10)H(8)O(2), (I), and C(13)H(14)O(3), (II), the 2-acetyl-4-ethynylphenol unit displays a planar geometry, which is stabilized by an intra­molecular O—H⋯O hydrogen bond. The crystal structure of (I) is constructed of infinite strands, along [101], of C—H⋯O=C hydrogen-bonded mol­ecules, which in turn are linked by C—H⋯π inter­actions. In the crystal of (II), which crystallized with three independent mol­ecules per asymmetric unit, the non-polar parts of the mol­ecules form hydro­phobic layered domains, parallel to (10-1), which are separated by the polar groups. While the 2-acetyl­phenol part of the mol­ecules are involved in O—H⋯O=C hydrogen bonding, the ternary OH groups creates a cyclic pattern of O—H⋯O hydrogen bonds.