Toward the Total Synthesis of Alpkinidine: Synthesis of Haloquinone CE Ring System Synthons and Attempted Nucleophilic Bisannulation was written by Buccini, Marco;Tham, Louisa;Dhoro, Francis;Skelton, Brian W.;Williams, Craig M.;Piggott, Matthew J.. And the article was included in ACS Omega in 2022.Reference of 628-13-7 This article mentions the following:
Model chem. involving the bisannulation of 2,3-dichloro-1,4-naphthoquinone with the ester enolate derived from Et ester of o-nitrophenylacetic acid, which rapid assembled the ABCD ring system of a pentacyclic pyrroloacridine, has been applied to the attempted synthesis of the marine natural product alpkinidine. The reaction of Et ester of o-nitrophenylacetic acid with 6,7-dichloro-2-methylisoquinoline-1,5,8(2H)-trione, required to extend the model strategy to alpkinidine, was unfruitful, giving only complex mixtures Efforts to direct the regiochem. of the key Michael substitution step using 6-bromo-2-methylisoquinoline-1,5,8(2H)-trione afforded an adduct sharing the complete carbon skeleton of alpkinidine, but this could not be elaborated to the natural product. In the experiment, the researchers used many compounds, for example, Pyridinehydrochloride (cas: 628-13-7Reference of 628-13-7).
Pyridinehydrochloride (cas: 628-13-7) belongs to pyridine derivatives. Pyridine’s the lone pair does not contribute to the aromatic system but importantly influences the chemical properties of pyridine, as it easily supports bond formation via an electrophilic attack. 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 628-13-7