Synthesis of Imidazolo [5, 4-b] carbazole-4, 10-quinones

G Desforges, C Bossert, C Montagne, B Joseph

Index: Desforges, Gwenaelle; Bossert, Cecile; Montagne, Cyril; Joseph, Benoit Synlett, 2004 , # 7 p. 1306 - 1308

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Citation Number: 2

Abstract

Selective halogen-metal exchange at position-5 of 3a was initially carried out with EtMgBr (1.1 equiv) at 0 °C, [15] then indole 4 [16] was added to the solution to afford a mixture of alcohol 5a and lactone 6 in 52% combined yield (Scheme [2] , Table [1] entry 1). Replacement of the Grignard reagent by BuLi (1 equiv) at -78 °C led to the lone alcohol 5a in 49% optimised yield. ... It is noteworthy that better coupling yield (83%, drawing not shown) was obtained ...