Veronika Kovač

FERROCENE COMPOUNDS XXIII. SYNTHESIS AND REACTIONS OF THE NEW TYPE OF METHYL FERROCYLOXYALKANOATES

The new types of ferrocenyloxaaliphatic acid ester, FcCHROCHR′COOMe (R = H, Me, Ph; R′ = H, Me) (7) have been prepared by the action of alkoxides derived from methyl glycolate or methyl lactate on the corresponding ferrocenylcarbinyl acetates (2) or N,N,N-trimethylferrocylammonium iodides (4). The esters obtained were accompanied by a small quantity of oligomeric esters, FcCHR(OCHR′CO)n OMe (9), and with more or less ferrocyl methyl ethers (8). As opposed to the alkaline hydrolysis of the analogous methyl benzoxyacetate (6) into benzoxyacetic acid (5) the acidification of sodium alkanoates 10 obtained by saponification of esters 7 gave unexpectedly the corresponding ferrocenylcarbinols 1. In a similar way the esters 7 were converted into mixtures of the mentioned carbinols and diferrocyl ethers 11 under action of aqueous hydrochloric acid. The mechanisms of the reactions 10 → 1 and 7 → 1, 11 are discussed.

Structuring new alginate network aimed for delivery of dandelion (Taraxacum officinale L.) polyphenols using ionic gelation and new filler materials

Alginate hydrogels are often used for immobilization of plant-derived bioactive compounds by fast and simple ionic gelation technique. However, the structure of alginate gel network is very porous and mostly result with high-diffusion rates of encapsulated compound, what limits its application as delivery vehicle. In order to prevent losses of bioactives and prepare efficient encapsulation systems, the aim of this study was to evaluate a potential of new natural fillers, cocoa powder (CP) and carob (C) for structuring alginate network aimed for encapsulation of aqueous dandelion (Taraxacum officinale L.) leaf extract using ionic gelation. Whey protein isolates served as a standard filler. The influence of different concentrations of gelling medium (2% and 3% calcium chloride) on encapsulation properties of alginate systems was also evaluated. Calcium concentration affected morphological properties (more acceptable when using 3% CaCl2), while textural properties and encapsulation efficiency of polyphenols and retained antioxidant capacity were more influenced by selected delivery materials. Alginate-whey protein isolates beads were scored with the highest loading capacity of polyphenols (>93%), while newly formulated binary mixtures (alginate-cocoa powder and alginate-carob) also enabled highly efficient entrapment of polyphenols (>88%). The slowest release of polyphenols in simulated gastrointestinal fluids were obtained when alginate was combined with CP and C, where system alginate-cocoa powder prepared with lower concentration of calcium chloride (2% CaCl2) enabled the most extended release of total polyphenols and hydroxycinnamic acids. Obtained results strongly justified implementation of new plant-derived functional fillers (cocoa powder and carob) for encapsulation purposes and opened new directions for designing of binary carriers.

N,N-Dibenzoyl-ferrocenecarboxamide.

In the title compound, [Fe(C5H5)(C20H14NO3)], the cyclopentadienyl rings deviate by 9.3 (2)° from an eclipsed conformation, defined by C—Cg 1—Cg 2—C pseudo-torsion angles ranging from 8.8 (1) to 9.85 (1)°. The coordination at the N atom is slightly pyramidal, as indicated by the angular sum around it of 352.6°. The amide group is inclined at 17.86 (9) and 27.27 (11)° with respect to the aromatic rings. In the crystal, molecules are linked by one C—H⋯O hydrogen bond and one C—H⋯π interaction into a two-dimensional framework parallel to the b axis.

SYNTHESIS OF SOME 2H-PYRONE AND FERROCENE CONTAINING HETEROCYCLIC SYSTEMS

Reactions of ethyl 2-hydroxy-4-(4-hydroxy-6-methyl-2-oxo-2H-pyran-3-yl)-4-oxobut-2-enoate (1) with o-phenylenediamine, 3, 4-dimethyl- or 3, 4-dichloro-o-phenylenediamine gave mixtures of the corresponding 3-[2-(4-hydroxy-6-methyl-2-oxo-2H-pyran-3-yl)-2-oxoethylidene]-1, 2, 3, 4-tetrahydroquinoxa-lin-2-ones (2), ethyl 4-(o-aminophenylimino)-2-hydroxy-4-(4-hydroxy-6-methyl-2-oxo-2H-pyran-3-yl)-but-2-enoate (3), ethyl 4-(4-hydroxy-6-methyl-2-oxo-2H-pyran-3-yl)-5H-1, 5-benzodiazepine-2-carboxylates (4), and ethyl 2-hydroxy-3-[3-methyl-1-oxo-1H, 5H-pyrano[4, 3-b][1, 5]benzodiazepin-11-yl]prop-2-enoates (5). By the action of 3-amino-1-phenyl-2-pyrazolin-5-one on 1 ethyl 2-phenyl-4-(4-hydroxy-6-methyl-2-oxo-2H-pyran-3-yl)-3-oxo-3-pyrazolino[3, 4-b]pyridine-6-carboxylate (6) was obtained. Reactions of ethyl 4-ferro-cenyl-1, 4-dioxobutanoate (8) and o-phenylenediamine gave a mixture of 3-(2-ferrocenyl-2-oxoethylidene)-1, 2, 3, 4-tetrahydro-quinoxalin-2-one (9) and ethyl 4-ferrocenyl-1, 5-benzodiazepine-2-carboxylate (10).