Efficient and Regioselective Synthesis of Phenothiazine via Ferric Citrate Catalyzed C-S/C-N Cross-Coupling was written by Das, Tonmoy Chitta;Imam Quadri, Syed Aziz;Farooqui, Mazahar. And the article was included in Letters in Organic Chemistry in 2019.SDS of cas: 82702-31-6 This article mentions the following:
Efficient C-S and C-N cross-coupling reactions have been developed for regioselective, scalable and environmentally benign synthesis of substituted phenothiazine derivatives I (R = H, CN, COOMe, CONH2, Cl, COOH, Br, CF3). Cross-coupling reactions were demonstrated on various challenging substrates using non-toxic, highly economical, readily available ferric citrate as a catalyst to get desired products I with high regioselectivity. Atom economy is the added advantage of this protocol since addnl. N-protection step before coupling and eventual deprotection of the same to obtain the desired product are not required. This is the first report on the use of inexpensive ferric citrate as a catalyst without involving any ligand for the synthesis of regioselectively substituted phenothiazines I. In the experiment, the researchers used many compounds, for example, Methyl 3-bromo-4-fluorobenzoate (cas: 82702-31-6SDS of cas: 82702-31-6).
Methyl 3-bromo-4-fluorobenzoate (cas: 82702-31-6) belongs to organobromine compounds. Bromine is more electronegative than carbon (2.9 vs 2.5). Consequently, the carbon in a carbon閳ユ彽romine bond is electrophilic, i.e. alkyl bromides are alkylating agents. The principal reactions for organobromides include dehydrobromination, Grignard reactions, reductive coupling, and nucleophilic substitution.SDS of cas: 82702-31-6
Referemce:
Bromide – Wikipedia,
bromide – Wiktionary