It was found that imidazole prevents the side process of diarylethenes photocyclization and the photodegradation of photochromic compounds.

No abstract

Data on the synthesis of thiazoles systems condensed with heterocycles are classified. The principal directions in the practical application of these substances are briefly discussed.

A convenient approach to the synthesis of the previously unknown 7H‐furo[3,2‐b]pyran‐7‐ones based on the intramolecular cyclization of carbonyl derivatives of 5‐hydroxy‐2‐methyl‐4H‐pyran‐4‐one has been elaborated. Key intermediates in the synthesis of the target 7H‐furo[3,2‐b]pyran‐7‐ones are 3‐hydroxy‐6‐methyl‐2‐(2‐oxo‐2‐arylethyl)‐4H‐pyran‐4‐ones. They are formed as a result of multicomponent condensation of 5‐hydroxy‐2‐methyl‐4H‐pyran‐4‐one with arylglyoxals and 4‐methoxyaniline.

C Acylation of Meldrum´s acid by (het)arylacetic acids in ethanol in the presence of 1,1' carbonyldiimidazole leads to ethyl 4 (het)aryl 3 oxobutanoates in high yields.