7-Hydroxyflavanone (I) and 7-Ethoxycarbonylmethoxyflavanone (II)

5,2′-Dihydroxy-7-methoxyflavanone

“…The C2-C3 bond length of 1.500 (6) Å is in agreement with the corresponding values observed in flavanone structures: 1.502 (5) Å in 7-hydroxyflavanone (Kendi et al, 1995a), 1.528 (7) Å in 7-hydroxy-4 0 -methoxyflavanone (Kendi et al, 1995b) and 1.511 (5) Å in 3-chloroflavanone (Tomlin & Cantrell, 1990). In flavones, the C2-C3 bond is a double bond, with an average bond length of 1.34 Å (Kaneda et al, 1973).…”

“…The dihydropyranone ring adopts an envelope conformation; the deviation of atom C2 from the O1/C8a/C4a/C4/C3 plane is 0.537 (7) Å . A similar conformation is observed in 7-hydroxyflavonone, 7-ethoxycarbonyl methoxyflavanone (Kendi et al, 1995a) and 7hydroxy-4 0 -methoxyflavanone (Kendi et al, 1995b). The dihedral angle between the O1/C3-C8/C4a/C8a plane and the C1 0 -C6 0 benzene ring plane is 55.3 (1) .…”

“…The dihedral angle between the O1/C3-C8/C4a/C8a plane and the C1 0 -C6 0 benzene ring plane is 55.3 (1) . The corresponding angles are 103.0 (1) in 7-hydroxyflavanone, 121.5 (2) in 7ethoxycarbonylmethoxy flavanone (Kendi et al, 1995a), 65.2 (1) in 7-hydroxy-4 0 -methoxyflavanone (Kendi et al, 1995b) and 70.8 (1) in 5,7,4 0 -trimethoxyflavanone (Mariezcurrena, 1978).…”

Synthesis and Crystal Structure of Tricarbonyl(η6-flavanone)chromium(0)

“…The -pyrone ring exists in a 1,2-diplanar conformation where C(10), C(11), and O(4) are almost coplanar with the aromatic nucleus, whereas C(12) shows the largest deviation (0.482(3) A Ê ) from the mean plane of the residual atoms. The bond lengths O(4)±C(4), O(4)±C (12), and O(5)±C(10) agree well with those found in other avanone compounds [11].…”