Indanediones, rearrangement

The indenobenzazepines 314, obtainable from the corresponding protoberberines (Sections V,F,2 and V,G,2), were converted to the spirobenzyliso-quinolinediones 315 in 76% yield through hydrolytic bond cleavage and recyclization by sequential treatment with 4 N hydrochloric acid, bromine in acetic acid, and triethylamine, via the indanediones (Scheme 58) (166). A one-step stereoselective rearrangement of an indenobenzazepine to a spirobenzylisoquinoline was developed by Blasko et ah (167). O-Methylfumarofine (316)... 

The two general methods for preparation of 4-imidazoline-2-thiones are the reaction of acyloins with thioureas and the acid hydrolysis of alkyl- or arylthiureidoacetals. The above reactions have been summarized in a review by Hofmann. Aren and Bite recently reported that the 2-phenyl-2-thiureido-l,3-indanediones (17) undergo rearrangement in strong acid to produce in high yield a series of 4-imidazoline-2-thiones (18). 

Stream of nitrogen. The initial product, the jS-keto sulfoxide II, undergoes intramolecular ester condensation with formation of the 1,3-indanedione system. Ill, which in the presence of hydrochloric acid undergoes Pummerer rearrangement to 2-chloro-2-methylmercapto-l,3-indanedione (IV). This crystalline product (m.p. 63°) is obtained in yield of 80% and is hydrolyzed in boiling water nearly quantitively to ninhydrin (V). 

Usefully difunctionalised, 1,3-dichloro-isoquinolines are readily synthesized via Beckmann rearrangement of indanedione monoximes. ... 

In another example, addition of phenyl vinyl selenoxide into a mixture of an indanedione, hexamethyldisilazane, and TMSCl in dichloromethane affords the a-trimethylsiloxyselenide in 70% yield (eq 67). The reaction proceeds through a sequence of in situ formation of TMS silyl enol ether, Michael addition onto the phenyl vinyl selenoxide, and seleno Pummerer rearrangement of the resulting selenoxide. Trifluoroacetic anhydride and various other trialkylchlorosilanes give the same product for this reaction, but in much lower yields. 

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