
%0 Journal Article
%A Collins, DJ 
%A Fallon, GD 
%A Skene, CE 
%T Selective O-Methyloxime Formation From 6-Methoxy-2-[(1'-methyl-2',5'-dioxocyclopentyl)-methyl]-3,4-dihydronaphthalen-1(2H)-one
%J Australian Journal of Chemistry
%D 1994/04/01
%V 47
%N 4
%P 649-661
%K 
%R https://doi.org/10.1071/CH9940649
%U https://www.publish.csiro.au/paper/CH9940649 
%X Reaction of 6-methoxy-2-[(1&#8242;-methyl-2&#8242;,5&#8242;-dioxocyclopentyl)methyl]-3,4-dihydronaphthalen-1(2H)-one (4a) with 1 or 2 moles of O- methylhydroxylamine hydrochloride in pyridine gave (1&#8242;SR,2RS)-6-methoxy-2-[(1&#8242;-methyl-2&#8242;,5&#8242;-dioxocyclopentyl)methyl]-3,4-dihydronaphthalen-1(2H)-one (E)-2&#8242;-O-methyloxime (5a), or the corresponding 2&#8242;,5&#8242;-bis(O-methyloxime ) (6), respectively. A minor product from the formation of the bis (O- methyloxime ) (6) was the (Z) isomer (5b) of the mono(O- methyloxime ) (5a); the structure and stereochemistry of (5a) and (5b) were established by X-ray crystallography. Reduction of the keto  bis (O-methyloxime ) (6) with 0.25 mole of lithium aluminium hydride gave a diastereomeric mixture of the corresponding alcohols (7a), of which the major isomer was characterized by ester formation. The bis (O-methyloxime ) (6) could be hydrolysed to the parent triketone (4a), but it resisted deprotection with cetyltrimethylammonium permanganate. Reaction of the triketone (4a) with 1 mole of 4-anisidine in the presence of 4-toluenesulfonic acid resulted in retro Michael cleavage with formation of 3-(4&#8242;-methoxyphenyl)amino-2-methylcyclopent-2-en-1-one (1). 
