title: Two polymorphs of 4-propyl-3,4-dihydro-2H-naphtho[1,2-b]pyran-5,6-dione.
abstract: Two polymorphs of the title compound, C(16)H(16)O(3), have been obtained from the same solution. One polymorph, (I(m)), crystallizes in the monoclinic space group P2(1), while the other, (I(o)), crystallizes in the orthorhombic space group P2(1)2(1)2(1). The cell constants of the two polymorphs are surprisingly similar. Whereas the a and b axes are equal in the two structures, the c axis in (I(o)) is twice as long as that in (I(m)). The monoclinic angle beta is 95.084 (9) degrees compared with 90 degrees in the orthorhombic crystal system. The cell volume of (I(m)) is almost exactly half of the cell volume of (I(o)). The packing motifs are also very similar in the two structures. However, whereas the molecules in (I(m)) are related by a twofold screw axis just in the direction of the b axis, in (I(o)) there are twofold screw axes along all three directions of the unit cell.
authors.affiliation: Institut für Organische Chemie, J. W. Goethe-Universität Frankfurt, Max-von-Laue-Strasse 7, 60438 Frankfurt/Main, Germany.
authors.forename: Erli
authors.initials: E
authors.lastname: Sugiono
authors.forename: Michael
authors.initials: M
authors.lastname: Bolte
mesh_terms: D006575:Heterocyclic Compounds, 3-Ring / Q000737:chemistry*; D015394:Molecular Structure; D009281:Naphthalenes / Q000737:chemistry*; D011753:Pyrones / Q000737:chemistry*; D011809:Quinones / Q000737:chemistry*; D013237:Stereoisomerism
chemical_list: C527867:4-propyl-3,4-dihydro-2H-naphtho(1,2-b)pyran-5,6-dione; D006575:Heterocyclic Compounds, 3-Ring; D009281:Naphthalenes; D011753:Pyrones; D011809:Quinones