There are presented results regarding a new set of molecularly imprinted polymers (MIPs) based on acrylonitrile:acrylic acid (AN:AA) copolymer matrix. As template, it was used sclareol, an important anticancer bioactive compound, never used before for molecular imprinting. An emerging and insufficient studied MIP preparation method, namely the phase inversion, was used to prepare 0.8 mm spherical sclareol MIPs (S‐MIPs). Three AN:AA copolymers, having the initial monomer ratios 90:10, 80:20, and 70:30, were synthesized by radical copolymerization in emulsion, without emulsifier. After that, each copolymer was dissolved in the presence of the template (sclareol) in dimethylformamide. The imprinting and the morphology of these new materials were analyzed by rheology, elemental analysis, infrared spectroscopy, size exclusion chromatography, thermogravimetric analysis, differential scanning calorimetry, batch rebinding tests, and Scatchard analysis. The conclusion was that the AN:AA‐80:20 matrix proved to be the optimized solution between high rigidity (given by the AN segments) and high affinity for the template (given by AA segments), the average imprinting factor for this system being 2.67. POLYM. ENG. SCI., 54:1484–1494, 2014. © 2013 Society of Plastics Engineers

An efficient one step, retro-biomimetic procedure for the synthesis of natural products having the atisane structure is described (Scheme 2), natural products which are components of medicinal plants and possess relevant biological activity. Their structures were confirmed by chemical transformations and spectral data. The starting materials were the known ent-kaur-16-en-19-oic acid (1) and ent-trachyloban-19-oic acid (2), diterpenoids readily available from the waste of sunflower.Introduction. -Tetracyclic atisanes, beyeranes, kauranes, and pentacyclic trachylobanes represent an important group of biosynthetically closely related polycyclic diterpenes, many of which display a wide range of biological activities [1 -7]. According to the hypothesis of diterpene biogenesis [8], diterpenes belonging to the families of ent-beyerene (A), ent-kaurene (B), ent-trachylobane (C), and ent-atisene (D) might all arise from (À)-copalyl pyrophosphate E via nonclassical carbocations such as F as common intermediates (Scheme 1). This hypothesis [8] has been formulated on the basis of the known isoprene rule and, to the best of our knowledge, has not been turned down yet. Scheme 1 provides a general overview of this biogenetic scheme, and our primary intention was to perform the retro-biomimetic transformation of ent-kaurene (B) to ent-beyerene (A) or ent-atisene (D) (path B ! F ! A or D).The rearrangements of ent-kaurane-and ent-trachylobane-type diterpenes have been reported under the action of different reagents [9]. Most of the examples relate on the reactions involving the formation of the nonclassical carbocation of type F (Scheme 1). It is well-known from the work of Olah and co-workers [10] that superacids are very convenient generators of these species, and our own experience on the use of fluorosulfuric acid (¼ fluorosulfonic acid; FSO 3 H) as an efficient promoter of terpenoid cyclizations [11 -15] and rearrangements [16 -18] provided a motivation to investigate the behavior of ent-kaur-16-en-19-oic acid (1) [19] and ent-trachyloban-19-oic acid (2) under superacid treatment (Scheme 2).

Thermogravimetric analysis (TG), derivative thermogravimetry (DTG), differential scanning calorimetry (DSC), dynamic mechanical thermal analysis, simultaneous differential thermogravimetry (SDT) coupled with mass spectrometry (MS), and pyrolysis coupled with gas chromatography/mass spectrometry (Py-GC/MS) were used to characterize molecularly imprinted polymers (MIPs) obtained with two anti-cancerous template molecules, diosgenin and sclareol, imprinted in acrylonitrileacrylic acid copolymer matrices. First of all, TG analyses revealed a specific mass loss in the temperature range 220-300°C characteristic to diosgenin-MIPs, while for the sclareol-MIPs, the specific interval was 100-240°C. Further, the DSC analyses evidenced two major aspects: first, that the copolymer matrices have a single glass transition temperature (T g ), which confirms the random statistic copolymer structure, an essential characteristic of a homogenous MIP matrix; secondly, both templates influence the T g values of the MIPs, fact that is an additional proof of molecular imprinting. The SDT results confirmed the TG and DSC results and, additionally, proved that the system with higher acrylic acid content generates stronger template-matrix interactions via hydrogen, van der Waals, and other non-covalent forces, fact that appears as an increased thermal stability on the TG curve and a higher maximum for template decomposition on the DTG curve. The MS results evidenced that a single mass fragment, 139 ± 1 m/z, characteristic for the class of steroid sapogenines of which diosgenin belongs, is enough to prove, qualitatively and quantitatively, the molecular imprinting and the template elution. As global conclusion, the applied thermal analyses proved to be exceptional tools for analyzing these molecularly imprinted polymers.

The known diterpenic ester – 15α-angeloyl-ent-kaur-16-en-19-oic (angeloylgrandifl oric) acid has been isolated from the dry wastes of Helianthus annuus L. The synthesis of 15α-hydroxy- and 15-oxo-ent-kaur-16-en-19- oic acids starting from ent-kaur-16-en-19-oic acid has been performed.