Photochemical Synthesis and Electrochemical and Photophysical Properties of 2,7-Diarylbenzo[1,2-d:4,3-d']bis(thiazoles).

This article focuses on the development of practical approaches to the preparation of benzo[1,2-:4,3-']bis(thiazoles) using blue light-induced photochemical cyclization of '-(1,4-aryl)dithioamides in the presence of -chloranil as a mild oxidant. The proposed method allows to obtain benzo[1,2-:4,3-']bis(thiazoles) containing donor substituents in the conjugated chain. Photophysical and (spectro)electrochemical properties of 2,6-di([2,2'-bithiophen]-5-yl)benzo[1,2-:4,3-]bis(thiazole) and -benzo[1,2-:4,5-']bis(thiazole) are studied in detail.

Novel Approach to the Synthesis of 3-amino-4-arylpyridin-2(1)-one Derivatives.

Unlabelled: The reaction of 4-arylidene-2-phenyloxazol-5(4)-ones with enamines of ethyl acetoacetate gave 4-aryl-2-methyl-6-oxo-5-[(phenylcarbonyl)amino]-1,4,5,6-tetrahydropyridine-3-carboxylic acid esters, which, when heated with phosphorus oxychloride, were converted into esters of 7-aryl-5-methyl-2-phenyloxazolo[5,4-]pyridine-6-carboxylic acids. Alkaline hydrolysis of these compounds gave 4-aryl-2-methyl-6-oxo-5-[(phenylcarbonyl)amino]-1,6-dihydropyridine-3-carboxylic acid esters.

Supplementary Information: The online version contains supplementary material available at 10.

Rearrangement of 7-Aryloxazolo[5,4-]pyridines to Benzo[][1,7]naphthyridine-4(3)-ones and Thieno[3,2-][1,7]naphthyridine-6(7)-ones.

In this work, we describe the development of the rearrangement for 7-aryl-substituted oxazolo[5,4-]pyridines treated with aluminum chloride into synthetically hard-to-reach benzo[][1,7]naphthyridinones. The discovered rearrangement is applied to a variety of electron-rich (hetero)arene substrates. It offers the advantages of mild conditions (90 °C temperature), fast reaction rates (<4 h), compatibility with air moisture, and the use of inexpensive commercial reagents.