Chemical and electrochemical routes to novel heterocycles and the generation of quinone methides.

Abstract

The structural assignment of the product from the palladium (11) promoted coupling of 3-benzoyl-1-methyl-indole was questioned, and thus alternative syntheses of the possible products were desired. Therefore both 1OH-5-methylindeno [1,2-b] indole and 6H-5-methylindeno-[2,1-b] indole were made, followed by attempts to oxidise the methylene group of both compounds. Eventually X-ray crystallography was used to confirm the product as 5-methylindeno [1,2-b] indole-10-one. Isochroman-3-one, 3,1-benzoxazin-3-one, and 1,4-dihydropyrano [4,5-b] indole-3-one were considered to be suitable precursors to their respective quinone methide intermediates, therefore substituted derivatives of these systems were required. Such derivatives in the isochromanone and benzoxazinone series were made, and an investigation of their behaviour during flash vacuum pyrrolysis undertaken. Attempts to make 1,4-dihydro-pyrano [4,5-b]indole-3-one were unsuccessful as the reduction of methyl 3-formyl-1 methylindolylacetate gave a "dimeric" compound rather than the desired product. The synthesis of 6,7-dimethoxy-4-(3,4-dimethoxy-phenylothyl) isochroman-3-one was achieved, and this compound was subjectod to electro-oxidation . The product was eventually proven to be 12H-3a,4,5-9b-tetrahydro- 7,8,11-trimethoxy-12-oxonaphtho [2 ,1 - d ] isochroman-3-one. Treatment of this compound with methylamine gave 11 11H-2a, 3, 4, 12, 12a-hexahydro-12a-hydroxymethyl-6,7,10-trimethoxy-1-methyl-11-oxonaphtho[2,1-c] oxindole. Finally studies towards an alternative synthesis of this novel ring system have been undertaken.

Date of Award	1985
Original language	English
Awarding Institution	University of Bath