ANALOGUES OF 2,2′-BIPYRIDYL WITH ISOQUINOLINE AND THIAZOLE RINGS. PART I

Abstract

Several analogues of 2,2′-bipyridyl, with isoquinoline, thiazole, and pyridine rings in various combinations, have been synthesized, and the effect of substituent groups in certain positions in the molecules studied with respect to their ability to react with cuprous and ferrous ion (the "cuproin" and "ferroin" reactions). The results agree with earlier work, and emphasize the desirability of two substituent groups "ortho" to the nitrogen atoms if a stable and sensitive cuprous ion reagent is wanted. The presence of one ortho substituent makes the reagent ineffective toward reaction with ferrous ion. Two of the compounds synthesized had groups in positions which did not allow a coplanar cis configuration of the molecule, and only in these cases were dipicrates formed; this situation is explained by assuming that hydrogen bond formation between the nitrogen atoms is not possible.