Authors give a report on four eriophyoid species which were new for the Hungarian fauna (Aculops berochensis Keifer and Delley; Aculops parakarensis Bagdasarian; Aculus ligustri Keifer; Aculus? crataegumplicans Cotte). Three of them were found on new host-plants.
Aculodes dubius (Nalepa), Aculodes mckenziei (Keifer) and Aceria tosichella Keifer were recorded for the first time in Hungary. Festuca pratensis, Phleum phleoides and Bromus inermis were found as new host-plants of Aculodes dubius, althought other plant species in these generas are known to be hosts of this mite. Aceria tulipae (Keifer) was indentified on Phleum pratense and Aceria tenuis (Nalepa) on Phleum phleoides, which were also new host-plants for them.
Authors:D. Kozma, J. Sztatisz, K. Tomor, G. Pokol and E. Fogassy
The optical resolution of racemic mandelic acid (I) by S-2-benzylamino-butanol (II) was performed in water, ethyl acetate,
and water saturated ethyl acetate. It was found that the efficiency of the resolution is three times higher in water saturated
ethyl acetate than in either water or ethyl acetate. The salt mixtures produced during the resolutions and the pure diastereoisomeric
salts were analyzed by TG, DSC and X-ray powder diffraction measurements. The R-(-)-IS-(+)-II salt has the higher melting
point and heat of fusion value which indicates that this is the more stable salt. Though the general assumption is that diastereoisomeric
salt pairs of successful optical resolutions form eutectic systems, the R-mandelic acid-S-2-benzylamino-butanol and the S-mandelic
acid-S-2-benzylamino-butanol system was found to behave in a different way. Melting did not start at or near the estimated
eutectic temperature. The difference can be explained either by miscibility in the solid phase (solid solution) or by a blocked
interaction between the crystals of the two solid salts. This unusual behaviour of the salt pair should be responsible for
the unusual difference in the efficiency of the resolutions performed in different solvents
Authors:Katalin Nemák, Mária Ács, D. Kozma and E. Fogassy
The phenomena of conglomerate formation-racemic compound formation were investigated in a series of five (N-alkyl)-2′,6′-pipecoloxylidides. The optically active enantiomers were prepared by optical resolution of the racemates using 2R,3R-tartaric acid and 0,0′-dibenzoyl-2R,3R-tartaric acid as resolving agent. By DSC measurement of the racemates and the enantiomer the binary phase diagrams were determined.
Authors:H. Simon, K. Marthi, Gy. Pokol, E. Fogassy and D. Kozma
O,O'-di-p-toluoyl-(2R,3R)-tartaric acid (DPTTA) was investigated as supramolecular complex (SMC) forming resolving agent with three racemic alcohols
(menthol, 4-methyl-2-pentanol, trans-2-iodo-cyclohexanol) by preparative scale experiments and thermoanalytical measurements.
Despite the very small structural difference (two methyl groups) between the O,O'-dibenzoyl-(2R,3R)-tartaric acid (DBTA) and DPTTA, their SMC forming properties with water and racemic alcohols is very different. While DBTA
forms SMC with all the three investigated alcohols, DPTTA forms SMC only with trans-2-iodo-cyclohexanol. DPTTA binds the guest compound less strongly and the stoichiometry of the SMC is also different. The
weaker interactions resulted in less effective optical resolutions. The results of these investigations remind us, that in
optical resolutions during the chiral discrimination process the weaker interactions have a determining role, since DBTA and
DPTTA have the possibility to form the same strong (O-HO and N-HO) hydrogen bond network.
Authors:D. Kozma, H. Simon, Gy. Pokol and E. Fogassy
The enantiomeric enrichment of N-methyl-amphetamine (MA) was tried by eight different preparative separation methods. The enrichment process was also studied by thermoanalitical methods (DSC,TG). There is no enantiomeric enrichment during fractional distillation and selective extraction of the liquid base. The enantiomeric mixture of MA·HCl can be enriched by crystallization or by sublimation. The most effective enrichment can be achieved by fractional crystallization or distillation of the reaction mixture after partial salt formation with hydrochloric acid. The separation is less effective in case of fractional steam distillation and selective extraction when the enantiomer and the racemate are distributed between two liquid phases. This supports the general experience that having a solid phase in the system makes enantiomer separation more efficient.
Authors:D. Kozma, Klára Tomor, C. Novák, G. Pokol and E. Fogassy
Racemic malic acid (I) was resolved by R-α-phenylethylamine(II). The S-(−)-I.R-(+)-II diastereoisomer was in excess in the precipitated salt. DSC curves and X-ray powder diffractograms proved that the diastereoisomeric salt mixture precipitated during the resolution was isomorphous with the optically pure S-(−)-I.R-(+)-II salt. The diastereoisomeric salt mixture containing the R-(−)-I.R-(+)-II salt in abundance bound crystal solvate (water or methanol) when produced by the total evaporation of the mother liquor, while the optically pure R-(−)-I.R-(+)-II salt crystallized without solvate. It is generally assumed that solid solution formation takes place when the two diastereoisomers are alike and the high similarity results in less efficient enantiomer separation.
Authors:D. Kozma, C. Novák, G. Pokol and E. Fogassy
The products obtained in the optical resolution of the N-methylamphetamine by the Pope-Peachy method, using half equivalent R, R-tartaric acid and half equivalent hydrochloric acid in absolute ethanol were investigated by thermoanalytical methods. The DSC measurements of the precipitated salts provide sufficient information for following the progress of the resolution. In this way, the results of the resolution can be estimated with the precision of about 5% optical purity.