Péter Horváth

Comparative synthesis of some new quinazoline derivatives via tetrakis(triphenylphosphine)palladium(0) catalysed Suzuki‐Miyaura cross‐coupling reaction in “green” propylene carbonate (PC) and dimethoxyethane. Three haloquinazolines were synthesised for Suzuki‐cross‐coupling from 5‐bromoanthranilic acid. Sufficient and easy method for the elimination of PC is developed, thus the optimization of the synthesis of some quinazoline derivatives was carried out. Reactions with 2‐chloro‐6‐bromo‐3‐phenylquinazolin‐4(3 H )‐one proceeded faster and with a higher yield in PC than in dimethoxyethane, thus for some reactants PC is a good choice for greener synthesis. Practical considerations for using PC include shorter reaction times, improved yields, and the elimination of unnecessary solvent distillation, leading to significant energy savings. This facilitates the execution of energy‐efficient reactions in a notably environmentally friendly solvent. In contrast to DME, the use of PC does not necessitate special pre‐treatments. Moreover, less PC is required due to its high boiling point and low volatility. Considering these properties, coupled with the consistent need for chromatographic purification, the use of PC in the Suzuki‐Miyaura cross‐coupling reaction emerges as a superior and greener alternative compared to DME.

The stability of host–guest complexes of two NSAID drugs with similar physicochemical properties, fenbufen and fenoprofen, was investigated by comparing induced circular dichroism and 1H nuclear magnetic resonance methods using eight cyclodextrins of different degrees of substitution and isomeric purity as guest compounds. These cyclodextrins include native β-cyclodextrin (BCyD), 2,6-dimethyl-β-cyclodextrin 50 (DIMEB50), 80 (DIMEB80) and 95% (DIMEB95) isomerically pure versions, low-methylated CRYSMEB, randomly methylated β-cyclodextrin (RAMEB) and 4.5 and 6.3 average substitution grade hydroxypropyl-β-cyclodextrin (HPBCyD). The stability constants obtained by the two methods show good agreement in most cases. For fenbufen complexes, there is a clear trend that the stability constant increases with the degree of substitution while isomer purity has a smaller effect on the magnitude of stability constants. A significant difference was found in the case of DIMEB50 when compared to DIMEB80/DIMEB95, while the latter two are similar. In the fenbufen–fenoprofen comparison, fenbufen, with its linear axis, gives a more stable complex, while fenoprofen shows lower constants and poorly defined trends.