| 1. |
- Digaitis, Ramūnas, PhD, et al.
(författare)
-
Hydration and dehydration induced changes in porosity of starch microspheres
- 2022
-
Ingår i: Carbohydrate Polymers. - : Elsevier. - 0144-8617 .- 1879-1344. ; 291, s. 119542-119542
-
Tidskriftsartikel (refereegranskat)abstract
- Characterization and tuning of the porosity of amorphous starch materials are important for many applications, including controlled release of encapsulated proteins. The porosities of these materials in dry and hydrated states can have different physicochemical origins and properties. Here, porosities of dry cross-linked starch microspheres and their hydration-induced transformations were characterized by small angle X-ray scattering, scanning electron and optical microscopies, thermogravimetric analysis, sorption calorimetry, nitrogen sorption, and helium-pycnometry. The analyses revealed that dry microspheres consist of porous cores with pore diameters below 100 nm and shells which appeared to be denser but contained wider pores (100–300 nm). The outer crust of the microspheres shell is non-porous, which restricts diffusion of nitrogen, water, and ethanol. Partial hydration triggered an irreversible collapse of dry porosity at 12 wt% water. Further hydration resulted in interfacial changes and promoted wet porosity, related to characteristic distances between polymer chains.
|
|
| 2. |
- Manner, Sophie, et al.
(författare)
-
Asymmetric baker's yeast reductions of bridgehead-substituted bicyclo[2.2.2]octane-2,6-dione derivatives followed by conversion into catalytically active BODOLs for the diethylzinc addition to benzaldehyde.
- 2010
-
Ingår i: Tetrahedron. - : Elsevier Ltd.. - 0957-4166 .- 1362-511X. ; 21:11-12, s. 1374-1381
-
Tidskriftsartikel (refereegranskat)abstract
- 4-Substituted bicyclo[2.2.2]octane-2,6-diones I [R = acetyl, benzyl, allyl, etc.] have been synthesized and tested as substrates in the enantioselective redn. with baker's yeast to give the corresponding hydroxy ketones II [R = acetyl, benzyl, allyl, etc.]. It was found that the deriv. bearing a TIPSO group at the 4-position was not reduced at all while that with a TBDMSO group gave 87% yield and 46% ee. Other 4-oxy functionalized derivs. were reduced with varying yields (36-87%) and ees (10-82%). The best result was obtained for the 4-Oallyl deriv. (80% yield, 82% ee). The hydroxy ketones carrying the benzyloxy and allyloxy groups at the 4-position were converted into the corresponding BODOLs III [R = allyl, benzyl], which were tested as catalysts in the diethylzinc addn. to benzaldehyde. In this reaction the ees were 90% and 89%, resp., which showed that BODOLs substituted at the 4-position are essentially as good catalysts in this reaction as those bearing a hydrogen. [on SciFinder(R)]
|
|
| 3. |
- Manner, Sophie, et al.
(författare)
-
Spiro-bicyclo[2.2.2]octane derivatives as paclitaxel mimetics. Synthesis and toxicity evaluation in breast cancer cell lines.
- 2013
-
Ingår i: Organic and Biomolecular Chemistry. - : Royal Society of Chemistry (RSC). - 1477-0539 .- 1477-0520. ; 11:41, s. 7134-7144
-
Tidskriftsartikel (refereegranskat)abstract
- Paclitaxel is one of the most important anti-cancer agents introduced during the last 20 years. However, the use of paclitaxel is limited by undesirable side effects as well as the development of drug resistance. Here, we report a synthetic strategy towards spiro-bicyclo[2.2.2]octane derivatives, which includes double Michael addition and ring-closing metathesis as key synthetic steps. This strategy was used to synthesize a series of spiro-bicyclic compounds designed to be paclitaxel mimetics, which were evaluated in human breast-derived cell lines. One of these paclitaxel mimetics showed toxicity, although at higher concentrations than paclitaxel itself. In addition, two other spiro-bicyclic compounds, lacking the paclitaxel side chain, showed toxicity.
|
|
