A study on the conversion of indanones into carbostyrils
Yasuhiro Torisawa1, Takao Nishi, Jun ichi Minamikawa
1Process Research Laboratory, Second Tokushima Factory, Otsuka Pharmaceutical Co., Ltd., Kawauchi, Tokushima, 771-0182, Japan. torisawa@fact.otsuka.co.jp
Abstract:
We have surveyed the utility of Beckmann rearrangement for the conversion of indanones into carbostyrils. Initial attempts at the conversion of 6-methoxy indanone oxime under classical conditions resulted in the formation of the two unusual products: 2-sulfonyloxyindanone and the dimeric product. This unusual rearrangement was also observed by the treatment of some metal triflates species. Further investigation has led to the development of reliable conditions starting from oxime mesylate (not oxime tosylate), in which some strong Lewis acid catalyst (ZrCl(4)) was employed in either a conventional or non-conventional solvent system. The advantage of the new protocol is highlighted by the simple work up and direct isolation of the product in 65% isolated yield.
Related Concept Videos
Stability of Conjugated Dienes
A comparison of the enthalpies of hydrogenation of dienes reveals that conjugated dienes release less heat on hydrogenation, rendering them more stable than their nonconjugated analogs.
Alkynes to Aldehydes and Ketones: Hydroboration-Oxidation
One of the convenient methods for the preparation of aldehydes and ketones is via hydration of alkynes. Hydroboration-oxidation of alkynes is an indirect hydration reaction in which an alkyne is treated with borane followed by oxidation with alkaline peroxide to form an enol that rapidly converts into an aldehyde or a ketone. Terminal alkynes form aldehydes, whereas internal alkynes give ketones as the final product.
Diels–Alder Reaction Forming Bridged Bicyclic Products: Stereochemistry
Stereoisomerism of Cyclic Compounds
Carboxylic Acids to Methylesters: Alkylation using Diazomethane
Directing and Steric Effects in Disubstituted Benzene Derivatives


