Resumo

BRITO, Iván et al. ABSOLUTE CONFIGURATION OF 18-ACETOXY-CIS-CLERODA-3,13E-DIEN-15-OIC ACID. J. Chil. Chem. Soc. [online]. 2018, vol.63, n.3, pp.4086-4089. ISSN 0717-9707.  http://dx.doi.org/10.4067/s0717-97072018000304086.

In this paper we report the absolute configuration which has been determined from the refinement of the Flack parameter, x = 0.05(5), which indicate that the correct configuration had been assigned against 1353 (99%) CuKα Bijvoet pairs. On this basis the absolute configuration was assigned as C5R, C8S, C9R and C10S. The structure of 18-acetoxy-cis-cleroda-3,13E-dien-15-oic acid consists of a clerodane skeleton and the corresponding methyl groups are α-oriented (C8, C9) while C5 is β-oriented. The acidic lateral chain is β-oriented and the double bond between C13 and C14 has E isomeric. The ciclohexene, cyclohexane rings are cis fused, and in an sofa and chair conformation respectively. In the crystal the molecules are linked by one intermolecular O—H…O hydrogen bond forming 1D-dimensional chain with distance donor-acceptor of 2.060(6)Å with graph-set notation $C_1^1$(15).

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