Studies on ketene and its derivatives. CX. Synthesis of 1,3-dimethoxyfluoren-9-ones was written by Nakano, Jun;Katagiri, Nobuya;Kato, Tetsuzo. And the article was included in Chemical & Pharmaceutical Bulletin in 1982.Quality Control of Ethyl 3-oxo-3-(m-tolyl)propanoate This article mentions the following:
1,3-Dimethoxyfluoren-9-ones (I; R, R2 = H, Me, MeO; R1 = H; R1R2 = benzo) were prepared from dihydroxybenzoates (II; R = H, R4 = EtO) (III). Thus, cyclocondensation of diketene with Et 3-aryl-3-oxopropionates in the presence of NaH in THF gave III, which were treated with MeI followed by alc. NaOH to give II (R3 = Me, R4 = HO) (IV). Cyclization of IV with (CF3CO)2O gave I. In the experiment, the researchers used many compounds, for example, Ethyl 3-oxo-3-(m-tolyl)propanoate (cas: 33166-79-9Quality Control of Ethyl 3-oxo-3-(m-tolyl)propanoate).
Ethyl 3-oxo-3-(m-tolyl)propanoate (cas: 33166-79-9) belongs to esters. Esters are widespread in nature and are widely used in industry. In nature, fats are in general triesters derived from glycerol and fatty acids. Esters are responsible for the aroma of many fruits. Many esters have the potential for conformational isomerism, but they tend to adopt an s-cis (or Z) conformation rather than the s-trans (or E) alternative, due to a combination of hyperconjugation and dipole minimization effects. The preference for the Z conformation is influenced by the nature of the substituents and solvent, if present. Lactones with small rings are restricted to the s-trans (i.e. E) conformation due to their cyclic structure.Quality Control of Ethyl 3-oxo-3-(m-tolyl)propanoate
Referemce:
Ester – Wikipedia,
Ester – an overview | ScienceDirect Topics