Publication Date

12-1989

Abstract

Derivatives of 2-methyl-3,4-dihydro-2H,5H-pyrano[3,2-c][1]benzopyran-5-one. (I) Racemic trans-2-hydroxy-4-(3-nitrophenyl), C19H15NO6, Mr = 353·33, triclinic, PĪ, a = 12·468 (1), b = 14·531 (3), c = 9·218 (2) Å, α = 99·00 (2), β = 98·03 (1), γ = 84·35 (1)°, V = 1628·3 (7) Å3, Z = 4, Dx= 1·441 g cm-3, λ (Cu ) = 1·54184 Å, μ = 8·679 cm-1, F(000) = 736, T = 294 K, final R = 0·042 for 4981 observations [I ≥ 3δ(I)]. The asymmetric unit contains two enantiomeric molecules [(2R,4R) and (2S,4S)] unrelated by crystallographic symmetry, and differing slightly in conformation. Hydrogen bonding occurs between a donor hydroxyl on one enantiomer (A) and a receptor carbonyl oxygen on another (B), O···O = 2·752 (2) Å, and between a donor hydroxyl (B) and a receptor hydroxyl (A), O···O = 2·923 (2) Å. Dihydropyran rings adopt half-chair conformations distorted toward the d,e-diplanar conformation. (II) Resolved (2R,4R)-( + )-trans-2-hydroxy-4-(4-fluorophenyl), C19H15FO4, Mr = 326·32, orthorhombic, P212121, a = 9·838 (4), b = 10·817(3), c = 14·777 (6) Å, V = 1572·6 (17) Å3, Z = 4, Dx = 1·374 g cm-3, λ (Cu Kα) = 1·54184 Å, μ = 8·351 cm-1, F(000) = 680, T = 294 K, final R = 0·040 for all 1583 observations. Hydroxyls are hydrogen bonded intermolecularly to carhonyl groups, O···O = 2·745 (3) Å. The embedded dihydropyran ring adopts a half-chair conformation.

Subjects

Conformation; Molecular structure

Publication Information

Copyright 1989 International Union of Crystallography. The original published version of this article may be found at http://dx.doi.org/10.1107/S0108270189003859.

DOI

10.1107/S0108270189003859

Document Type

Journal Article

Included in

Chemistry Commons

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