Intermediates for the synthesis of tetracyclic indole alkaloids. Synthesis of 4‐aminotetrahydrocarbazole derivatives

Abstract

An efficient method for the synthesis of 4‐aminotetrahydrocarbazole derivatives from 2,3‐dihydrospiro‐[1H‐carbazole‐1,2′‐(1,3)‐dithiolan]‐4‐(9H)‐one 1 is described. The structure of compound 6 has been confirmed by X‐ray structure analysis.

4-Methylcarbazole-3-carboxylic acid

“…The structures of 1,2,3,4-tetrahydrocarbazole derivatives with different substituents bonded at different positions of the carbazole core have been the subject of much interest in our laboratory. Examples include 1-benzyloxy-1,2,3,4-tetrahydrocarbazole, (II) , N-(1,2,3,4-tetrahydrocarbazole-1-yl)-2-methoxyacetamide, (III) , N-(2,2-dimethoxyethyl)-N-{9-methoxymethyl-1,2,3,4tetrahydro-spiro[carbazole-1,2 H -[1,3]dithiolan]-4-yl}benzamide, (IV) , 9-acetonyl-3-ethylidene-1,2,3,4-tetrahydrospiro[carbazole-1,2 H -[1,3]dithiolan]-4-one, (V) , spiro[carbazole-1(2H),2 H -[1,3]dithiolan]-4(3H)-one, (VI) (Ho È kelek et al, 1998), N-(2methoxymethyl)-N-{2,3,4,9-tetrahydrospiro[1H-carbazole-1,2-[1,3]dithiolan]-4-yl}benzenesulfonamide, (VII) (Patõr et al, 1997), and 2,3-dihydro-9-(phenylsulfonyl)carbazole-4(1H)one and 1,2,3,4-tetrahydrocarbazole-1-spiro-2 H -[1,3]dithiolane, (VIII) and (IX), respectively (Ho È kelek et al, 1994).…”

5-(3,6-Dibromo-9H-carbazol-9-yl)pentanenitrile

“…Tetrahydrocarbazole systems are present in the framework of a number of indole-type alkaloids of biological interest (Saxton, 1983). The structures of tricyclic, tetracyclic and pentacyclic ring systems with dithiolane and other substituents of the tetrahydrocarbazole core, have been reported previously (Patır et al, 1997;Hökelek & Patır, 1999). Substituted carbazole based monomers exhibit good electroactive and photoactive properties which make them the most promising candidates for hole transporting mobility of charge carriers (Cloutet et al, 1999) and photoluminescence efficiencies (Wei et al, 2006).…”

“…For tetrahydrocarbazole systems present in the framework of a number of indole-type alkaloids of biological interest, see: Saxton (1983). For related structures and background references, see: Patır et al (1997); Hö kelek & Patır (1999). For applications of carbazole derivatives, see: Cloutet et al (1999); Wei et al (2006); Tirapattur et al (2003); Taoudi et al (2001); Saraswathi et al (1999); Sarac et al (2000).…”

Ethyl 4-oxo-2,3,4,9-tetrahydro-1H-carbazole-3-carboxylate

“…For background to tetrahydrocarbazole systems present in indole-type alkaloids, see: Saxton (1983). For related structures, see: Hö kelek et al (1994Hö kelek et al ( , 1998Hö kelek et al ( , 2009; Patır et al (1997); Ç aylak et al (2007); Uludag et al (2009). For the use of 4-oxo-tetrahydrocarbazole in the syntheses of biologically active species, see: Kumar et al (2008); Ergü n et al (2002); Li & Vince (2006).…”