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 Regiodivergent Intramolecular Nucleophilic Addition of Ketimines for the Diverse Synthesis of Azacycles, published in 2020, which mentions a compound: 20028-53-9, mainly applied to indolyloxindole indoleacetate regioselective preparation; tetrahydrospiroquinolineoxindole regioselective diastereoselective enantioselective preparation; nitroethylaniline imine oxindole ketoester regioselective cyclization; sodium catalyst regioselective cyclization nitroethylaniline imine oxindole ketoester; copper catalyst stereoselective spirocyclization nitroethylaniline imine oxindole ketoester; transition state solvent effect regioselective cyclization nitroethylaniline imine oxindole; heterocycles; indoles; organocatalysis; reaction mechanisms; synthetic methods, SDS of cas: 20028-53-9.
Imines generated in situ or prepared from isatins or aryl α-ketoesters and 2-(2-nitroethyl)anilines underwent regioselective, diastereoselective, and enantioselective cyclization reactions to yield indolyloxindoles such as I and indoleacetates or tetrahydrospiroquinolineoxindoles such as II or tetrahydroquinolinecarboxylates. Cyclocondensation of oxindoles with 2-(2-nitroethyl)anilines in MeOH in the presence of p-TsOH followed by treatment with Na2CO3 in MeOH yielded indolyloxindoles such as I, while imines prepared from 2-(2-nitroethyl)anilines and α-ketoesters underwent cyclization in the presence of Na2CO3 and KHCO3 in MeOH to yield indoleacetates. In the presence of Cu(BF4)2 and a nonracemic bisoxazoline, imines prepared from isatins and 2-(2-nitroethyl)anilines underwent regioselective, diastereoselective, and enantioselective cyclization to yield tetrahydrospiroquinolineoxindoles. Selected products were further functionalized; I was converted in three steps to a nonracemic intermediate in the preparation of (-)-psychotrimine. Computational study of the mechanism and of the effect of solvent on the reaction regiochem. indicated that hydrogen-bonding interactions facilitate the nucleophilic attack of imines at the nitrogen atom.
Compounds in my other articles are similar to this one(2-Amino-5-chlorobenzaldehyde)SDS of cas: 20028-53-9, you can compare them to see their pros and cons in some ways,such as convenient, effective and so on.
Reference:
Tetrahydrofuran – Wikipedia,
Tetrahydrofuran | (CH2)3CH2O – PubChem