Facile Synthesis of Substituted Furo- and Pyrano-Carbazoles

Abstract

Simple and efficient method for the synthesis of substituted furo-and pyrano-carbazole derivatives from 1-hydroxycarbazoles was described.

Synthesis of Oxazino[4,3-a]indoles and biological applications

“…It was also reported by the same group that 9H-carbazol-1-ol substrates 60 reacted as nucleophilic clamps with oxalyl chloride in acidic media to give the corresponding [1,4]oxazio[2,3,4-j,k]carbazole-1,2-diones 61 with good yields [48] (Scheme 26). Westwood showed, in a study dedicated to the oxidative cleavage of oxazinocarbazoles 63, that such compounds were obtained from the reduction and internal cyclization of N-substituted tetrahydro-1H-carbazol-1-one derivatives 62 [49] (Scheme 27).…”

Fischer indole synthesis applied to the total synthesis of natural products

“…isolated from the genera Clausena and Murraya species, and in the case of 2-and 3-functionalized classes, their biogenesis were developed. 134 The total synthesis of natural products mukolidine 203 and mukoline 204 has been achieved by Chakraborty and co-workers in 1982. 135 As depicted in Scheme 42, this total synthesis initiated through a Japp-Klingemann reaction of toluenediazonium chloride 205 and 2-hydroxymethylenecyclohexanone 191 to give hydrazone 206.…”

Synthesis of benzofurans from the cyclodehydration of α-phenoxy ketones mediated by Eaton’s reagent

“…43–45 These protocols usually require long reaction times even in refluxing solvents, which encouraged us to find an alternative method to prepare benzofurans under moderate conditions. According to the literature, MeSO 3 H and P 2 O 5 46 are both reported as reagents for cyclodehydration reactions; however, their combined use to synthesize benzofurans is seldom reported. To our knowledge, there is only one example of this synthesis reported by Vedejs.…”