Expedient Synthesis of Substituted Benzoheterocycles using 2-Butoxy-2,3-dihydrofurans as [4+2] Benzannulation Reagents was written by Liu, Changhui;Huang, Wenbo;Wang, Man;Pan, Bin;Gu, Yanlong. And the article was included in Advanced Synthesis & Catalysis in 2016.Category: esters-buliding-blocks This article mentions the following:
2-Alkoxy-2,3-dihydrofurans were found to be versatile benzannulation reagents. Indoles can be synthesized in good to excellent yields via the [4+2] annulation of 2-butoxy-2,3-dihydrofuran with pyrroles catalyzed by copper bromide. With the same protocol, carbazoles can also be obtained when indoles are used as starting material with the aid of p-toluenesulfonic acid. This type of benzannulation reagent can also be used to synthesize benzofuran, benzothiophene and naphthalene derivatives in the presence of a catalytic amount of triflic acid in moderate yields. This benzannulation protocol features wide substrate scope and mild reaction condition. Moreover, most of examples have a good regioselectivity. In the experiment, the researchers used many compounds, for example, Ethyl 3-oxo-3-(thiophen-2-yl)propanoate (cas: 13669-10-8Category: esters-buliding-blocks).
Ethyl 3-oxo-3-(thiophen-2-yl)propanoate (cas: 13669-10-8) belongs to esters. Esters perform as high-grade solvents for a broad array of plastics, plasticizers, resins, and lacquers, and are one of the largest classes of synthetic lubricants on the commercial market. Esters contain a carbonyl center, which gives rise to 120° C–C–O and O–C–O angles. Unlike amides, esters are structurally flexible functional groups because rotation about the C–O–C bonds has a low barrier. Their flexibility and low polarity is manifested in their physical properties; they tend to be less rigid (lower melting point) and more volatile (lower boiling point) than the corresponding amides. Category: esters-buliding-blocks
Referemce:
Ester – Wikipedia,
Ester – an overview | ScienceDirect Topics