Methyleneketenes and methylenecarbenes. V. Condensation of ketones with isopropylidene malonate catalyzed by titanium tetrachloride and synthesis of a dibenzofuran was written by Baxter, Gary J.;Brown, Roger F. C.. And the article was included in Australian Journal of Chemistry in 1975.Reference of 15540-90-6 The following contents are mentioned in the article:
The TiCl4-pyridine-THF reagent of Lehnert will effect direct condensation of some aromatic ketones RCOR1(R = Ph, o-tolyl, 2,5-dimethyl-3-furyl; R1 = Me, Ph, Co2Me, piperidinocarbonyl; RR1 = 2,2′-biphenylylene) with isopropylidene malonate (Meldrum’s acid) to give I. The synthetic value of this reaction is explored in a synthesis of 7-methoxy-9-methyldibenzofuran-3-ol involving pyrolysis of I (R = 2,5-dimethyl-3-furyl), formylation of II with Cl2CHOMe and SnCl4, conversion of III to the 6-MeO analog. condensation with isopropylidene malonate, and pyrolysis of the product. A 1,9-dimethyldibenzofuran related to strepsilin could not be obtained in the same way. This study involved multiple reactions and reactants, such as 4,7-Dimethylindoline-2,3-dione (cas: 15540-90-6Reference of 15540-90-6).
4,7-Dimethylindoline-2,3-dione (cas: 15540-90-6) belongs to indole derivatives. The indole subunit is an almost ubiquitous component of biologically active natural products, and its study has been the focus of research for decades.Indole was synthesized in moderate yield via an o-naphthoquinone catalyzed tandem cross-coupling of substituted aniline and benzylamine under aerobic oxidation conditions.Reference of 15540-90-6
Referemce:
Indole alkaloid derivatives as building blocks of natural products from Bacillus thuringiensis and Bacillus velezensis and their antibacterial and antifungal activity study,
Preparation of Indole Containing Building Blocks for the Regiospecific Construction of Indole Appended Pyrazoles and Pyrroles