Atropisomerism is a special kind of stereoisomeric relationship that arises from the freezing of a certain conformation of an organic molecule, associated with a high rotational barrier about a single covalent bond. Atropisomerism has been originally described in orto-functionalyzed biphenyl derivatives, but a lot of other organic functionalities can present this structural phenomenon, characterized by the presence of chiral properties in compounds that don't present classical stereogenic centers. Atropisomeric compounds, intermediates and catalysts have well-know importance in organic synthesis, but the influence of the axial chirality in substances able to modulate biological systems is still not very exploited in drug design and development. In this context, the present account describes the importance of this structural property in the medicinal chemistry of different classes of bioactive compounds or therapeutic agents, emphasizing how atropisomerism could affect the molecular recognition of a ligand or a prototype by the target bioreceptor.

Copaifera multijuga Hayne é uma das espécies do gênero Copaifera da qual se extrai o óleo de copaíba. Além do uso como antiinflamatório e anti-séptico, o óleo de copaíba é utilizado na indústria de fragrâncias como fixador para perfumes, cosméticos e sabões. A fim de identificar as substâncias ativas no aroma do óleo de C. multijuga, CG-O-EM utilizando AEDA foi aplicada após a quantificação dos compostos por CG-DIC. Os resultados obtidos apontaram para delta-cadineno (1,9%, FD 64), delta-cadinol (0,9%, FD 128), óxido de cariofileno (0,2%, FD 64), (Z)-alfa-santalol (0,2%, FD 128), alfa-cadinol (0,1%, FD 128) e tau-muurolol (0,1%, FD 128) como as substâncias de odor mais ativo no aroma deste óleo de copaíba. Quanto à contribuição aromática dos enanciômeros do delta-cadineno analisada por CG-EM-O-quiral, somente o enanciômero (+)-delta-cadineno foi encontrado no óleo e apresentou aroma adocicado, verde e refrescante.

Copaifera multijuga Hayne is one of the Copaifera species from which copaiba oil is extracted. Employed in the composition of anti-inflammatory and antiseptic products used in phytotherapy, it is also used by the fragrance industry as a fixative in perfumes, cosmetics and in products such as soaps. To identify the active aroma compounds in C. multijuga oil bouquet, GC-O-MS using AEDA (Aroma Extract Dilution Analysis) was used after the quantification of the components by GC-FID. The results obtained pointed to minor compounds such as delta-cadinene (1.9%, FD 64), delta-cadinol (0.9%, FD 128), (Z)-alpha-santalol (0.2%, FD 128) caryophyllene oxide (0.2%, FD 64), alpha-cadinol (0.1%, FD 128) and tau-muurolol (0.1%, FD 128) as the most intense compounds in the odor of the copaiba oil studied. Chiral GC-O-MS showed (+)-delta-cadinene as the only enantiomer present in the oil, with a sweet, green and refreshing aroma.