24159-49-7Relevant academic research and scientific papers
The Course of Cyclic Ethylene Acetal Formation from 7a-Methyl-2,3,7,7a-tetrahydro-1H-indene-1,5(6H)-dione
Brown, Roger F. C.,Burge, Geoffrey L.,Collins, David J.
, p. 117 - 134 (2007/10/02)
All attemps to convert the dione (1a) into the 5-monoacetal (8) by direct ethylene acetal formation under mild conditions have led to complex mixtures usually containing the required monoacetal (8), its conjugated enone isomer (9), the diacetal (5) and the 1-monoacetal (2).The diacetal (5) readily forms a dimer (4) in the presence of anhydrous acid, but in dioxan containing aqueous sulfuric acid it is hydrolysed to the 5-monoacetal (8), isolated in 68percent yield after chromatographic separation from the dione (1a).For preparative purposes the most convenient and reliable method for the preparation of (8) is conversion of (1a) into the 1-cyanohydrin (34), formation of the corresponding 5-acetal (36), and elimination of HCN from the 1-cyanohydrin group with pyridine; this gave the 5-monoacetal (8) in 66percent overall yield.
