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Orientierung der nitromethylgruppe in nitroalkoholen: die kristall- und molekülstrukturen von vier freien und drei acetylierten 2,6-anhydro-1-desoxy-1-nitroalditolen

1989; Elsevier BV; Volume: 186; Issue: 1 Linguagem: Inglês

10.1016/0008-6215(89)84001-7

1873-426X

Jürgen Kopf, Cornelia Topf, Peter Köll,

Enzyme Structure and Function

The crystal structures of four free and three acetylated 2,6-anhydro-1-deoxy-1-nitroalditols, i.e., 2,6-anhydro-1-deoxy-1-nitro-d-glycero-d-gulo-heptitol, 2,6-anhydro-1-deoxy-1-nitro-d-glycero-l-manno-heptitol, 3,4,5,7-tetra-O-2,6-anhydro-1-deoxy-1-nitro-d-glycero-l-manno-heptitol, 2,6-anhydro-1-deoxy-1-nitro-l-manno-hexitol, 3,4,5-tri-O-acetyl-2,6-anhydro-1-deoxy-1-nitro-l-manno-hexitol, 2,6-anhydro-1-deoxy-1-nitro-d-galacto-hexitol, and 3,4,5-tri-O-acetyl-2,6-anhydro-1-deoxy-1-nitro-d-altro-hexitol, were resolved by X-ray diffraction using direct methods. In all compounds, the exocyclic nitromethyl group was found in an antiperiplanar position with respect to C-3 and is, thus, situated gauche to the ring oxygen atom. The oxygen atoms of the nitro group show a preference in their orientations to the hydrogen atoms at C-1 and C-2, one found in a position synclinal to H-12 and the other 1,3-synclinal to H-2. Die Kristallstrukturen von vier freien und drei acetylierten 2,6-Anhydro-1-desoxy-1-nitroalditolen, nämlich von 2,6-Anhydro-1-desoxy-1-nitro-d-glycero-d-gulo-heptitol, 2,6-Anhydro-1-desoxy-1-nitro-d-glycero-l-manno-heptitol, 3,4,5,7-Tetra-O-acetyl-2,6-Anhydro-1-desoxy-1-nitro-d-glycero-l-manno-heptitol, 2,6-Anhydro-1-desoxy-1-nitro-l-manno-hexitol, 3,4,5-Tri-O-acetyl-2,6-Anhydro-1-desoxy-1-nitro-l-manno-hexitol, 2,6-Anhydro-1-desoxy-1-nitro-d-galacto-hexitol und 3,4,5-Tri-O-acetyl-2,6-Anhydro-1-desoxy-1-nitro-d-altro-hexitol wurden durch Röntgenstrukturanalyse unter Verwendung direkter Methoden bestimmt. In allen Verbindungen findet sich die Nitromethylgruppe in antiperiplanarer Anordnung zu C-3 mit resultierender gauche-Anordnung zum Ringsauerstoffatom. Die Sauerstoffatome der Nitrogruppe bevorzugen Lagen, bei denen sich eines dieser Atome in synclinaler Position zu H-12 und das andere in entsprechender synclinaler 1,3-Position zu H-2 befindet.