Publication Date

11-1989

Abstract

Derivatives of 2-methyl-3,4-dihydro-2H-5H-pyrano[3,2-c][1]benzopyran-5-one. (I) Racemic trans-2-hydroxy-4-(2,3-dimethoxyphenyl), C21H20O6, Mr = 368·40, monoclinic, C2/c, a = 19·403 (7), b = 10·636 (8), c = 21·456 (13) Å, β = 123·94 (5)°, V = 3673·8 (85) Å3, Z = 8, Dx = 1·33 g cm-3, λ(Mo ) = 0·71078 Å, μ = 0·913 cm-1, F(000) = 1552, T = 295 K, final R = 0·056 for 2463 observations [I ≥ 2δ(I)]. Molecules are hydrogen bonded between hydroxyls and coumarin carbonyls, O···O 2·812 (3) Å. The dihydropyran ring is in the d,e-diplanar conformation. (II) Resolved (2R,4R)-( + )-trans-2-hydroxy-4-(4-methylphenyl), C20H18O4, Mr = 322·36, orthorhombic, P212121, a = 10·578 (4), b = 10·450 (5), c = 14·803 (7) Å, V = 1636·4 (22) Å3, Z = 4, Dx= 1·31 g cm-3, λ(Mo ) = 0·71078 Å, μ = 0·540 cm-1, F(000) = 680, T = 294 K, final R = 0·044 for 1580 observations [I ≥ 3 δ(I)]. Molecules are hydrogen bonded along a screw axis between hydroxyls and coumarin carbonyls, O···O 2·746 (3) Å. The dihydropyran ring is a nearly undistorted half-chair.

Subjects

Conformation; Molecular structure

Publication Information

Copyright 1989 International Union of Crystallography. The original published version of this article may be found here.

Document Type

Journal Article

Included in

Chemistry Commons

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