In organic chemistry, atoms other than carbon and hydrogen are generally referred to as heteroatoms. The most common heteroatoms are nitrogen, oxygen and sulfur. Now I present to you an article called A One-Step Synthesis of 2,4-Unsubstituted Quinoline-3-carboxylic Acid Esters from o-Nitrobenzaldehydes, published in 2010-05-21, which mentions a compound: 481054-89-1, mainly applied to nitrobenzaldehyde diethoxypropionic acid ester modified reductive Friedlaender reaction tin; quinolinecarboxylic acid ester preparation; tin chloride modified reductive Friedlaender reaction mediator, COA of Formula: C12H10BrNO2.
A straightforward and efficient one-step procedure for the synthesis of 2,4-unsubstituted quinoline-3-carboxylic acid Et esters, e.g., I (R1 = Me, Et; R2 = H, F, Cl, Br, OH), is described. The simple reductive cyclization is carried out by treating various substituted o-nitrobenzaldehydes with inexpensive, com. available 3,3-diethoxypropionic acid Et ester and SnCl2·2H2O in refluxing ethanol.
In addition to the literature in the link below, there is a lot of literature about this compound(Ethyl 6-bromoquinoline-3-carboxylate)COA of Formula: C12H10BrNO2, illustrating the importance and wide applicability of this compound(481054-89-1).
Reference:
Benzoxazole – Wikipedia,
Benzoxazole | C7H5NO – PubChem