Switching the reactivity of cyanomethylpyridinium salts in the 1,3-cycloaddition conditions with alkyl propiolates to cyanoindolizines or cyanoazaindolizinyl-indolizines was written by Moise, Iuliana-Monica;Ghinet, Alina;Shova, Sergiu;Bicu, Elena. And the article was included in Tetrahedron in 2020.Reference of 17281-59-3 This article mentions the following:
A particular reactivity of 1-cyanomethylpyridinium salts was revealed in the [3 + 2] cycloaddition conditions with alkyl propiolates. Cyanoindolizines I [R = H, 7-Me, 7-OMe, etc.] were obtained in reactions carried out at room temperature while refluxing in CH3CN provided unexpected Et or Me 3-(3-cyanoimidazo[1,2-a]pyridin-2-yl)indolizine-1-carboxylates II. The structure of the new 2:1 azaindolizine-indolizine adducts was secured by X-ray anal. Methodol. efforts had enabled the adjustment of the reactivity towards the formation of 3-cyanoindolizines I or cyanoazaindolizine-indolizines II. A mechanism for the formation of azaindolizine-indolizines was proposed. In the experiment, the researchers used many compounds, for example, 1-(Cyanomethyl)pyridin-1-ium chloride (cas: 17281-59-3Reference of 17281-59-3).
1-(Cyanomethyl)pyridin-1-ium chloride (cas: 17281-59-3) belongs to pyridine derivatives. In contrast to benzene, Pyridine’s electron density is not evenly distributed over the ring, reflecting the negative inductive effect of the nitrogen atom. One of the examples of pyridines is the well-known alkaloid lithoprimidine, which is an A3 adenosine receptor antagonist and N,N-dimethylaminopyridine (DMAP) analog, commonly used in organic synthesis.Reference of 17281-59-3