Yoshimura, Juji; Sugiyama, Yuichi; Nakamura, Hiroshi published the article 《Synthesis and substitution of 1,3,4,6-tetra-substituted-3,6-dihalo-2,5-piperazinediones》. Keywords: halopiperazinedione; piperazinedione dihalo; oxopiperazine dihalo.They researched the compound: Ethyl indoline-2-carboxylate( cas:50501-07-0 ).Quality Control of Ethyl indoline-2-carboxylate. Aromatic heterocyclic compounds can be divided into two categories: single heterocyclic and fused heterocyclic. In addition, there is a lot of other information about this compound (cas:50501-07-0) here.
Addition of Cl to 3,6-dimethylene- (I) and 3,6-dibenzylidene-1,4-dimethyl-2,5-piperazinediones gave isomers of the corresponding tetrachloride, e.g., II, and substitution of 1,3,4,6-tetramethyl-2,5-piperazinedione with Br also gave a tetrabromide III of the same type via successive elimination and addition reactions. Treatment of III with water and with methanolic NaOAc gave the corresponding 3,6-dihydroxy and dimethoxy derivatives, resp., while treatment with NaI, Na2S, NaSCN, or NaOSCMe gave only I and S in a good yield. Similar results were obtained in the case of octahydro-5H,10H-dipyrrolo[1,2-a:1′,2′-d]pyrazine-5,10-dione. However, bromination of 6,13-dioxo-6a,7,13a,14-tetrahydro-6H,13H-pyrazino[1,2-a:4,5-a’]diindole gave rise only to aromatization. Configurations of the isomers obtained and the reaction processes were discussed.
As far as I know, this compound(50501-07-0)Quality Control of Ethyl indoline-2-carboxylate can be applied in many ways, which is helpful for the development of experiments. Therefore many people are doing relevant researches.
Reference:
Tetrahydropyran – Wikipedia,
Tetrahydropyran – an overview | ScienceDirect Topics