As part of this master's thesis a series of novel 3-acylamino-2H-pyran-2-ones were prepared by introduction of a new protecting group on the 3-amine group with selected acid chlorides. Those were further reacted under thermal conditions with maleic anhydride in order to prepare new bicyclo[2.2.2]octene systems with two attached succinic anhydride fragments (products of double Diels–Alder cycloaddition), however in some cases thermodynamically more stable aromatic products (isobenzofuran derivatives) were formed instead of otherwise kinetically favoured bicyclic double adducts. Some of the prepared bicyclo[2.2.2]octene adducts were used in further derivatization reactions with selected nitrogen nucleophiles (hydrazine, n-butylamine and 3-picolyl amine).
A series of selected 3-acylamino-2H-pyran-2-ones were also tested under microwave irradiation conditions in the presence of ethyl vinyl ether and DABCO. By adjusting the reaction conditions (temperature, heating power, duration of reaction time) some novel benzene derivatives were successfully prepared.
In order to prepare oxabicyclo[2.2.2]octene adducts, which cannot be prepared by the conventional route by heating the reaction mixture due to the thermal instability of structures of this type, reactions with selected 2H-pyran-2-ones with various dienophiles were carried out under high-pressure conditions. However, I was only successful in two cases. In one case a double CO2-bridged adduct containing two oxabicyclo[2.2.2]octene units connected via an isophthalamide bridge was successfuly synthesized.
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