75775-73-4Relevant academic research and scientific papers
Antitumour polycyclic acridines. Part 1. Synthesis of 7H-pyrido- and 8H-quino-[4,3,2-kl]acridines by Graebe-Ullmann thermolysis of 9-(1,2,3-triazol-1-yl)acridines: Application of differential scanning calorimetry to predict optimum cyclisation conditions
Hagan, Damien J.,Gimenez-Arnau, Elena,Schwalbe, Carl H.,Stevens, Malcolm F. G.
, p. 2739 - 2746 (2007/10/03)
The thermal decomposition of a series of acridities substituted in the 9-position with 1,2,3-triazol-1-yl, benzotriazol-1-yl and naphthotriazol-1-yl groups has been studied by differential scanning calorimetry. Whereas the monocyclic triazole 7a shows a discrete melting endotherm followed by a decomposition exotherm corresponding to formation of the 7H-pyrido[4,3,2-kl]acridine 8, in the benzotriazoles 10a-e and naphthotriazole 10f these processes coincide with a single sharp exothermic transition attributed to cyclisation to polycyclic acridities 11a-f, respectively. The optimum conditions for the preparative scale synthesis of polycyclic acridines from triazole precursors utilised boiling diphenyl ether as the decomposition medium. A benzotriazol-1-ylacridine 10e substituted in the peri position with a methyl group behaved anomalously: as well as affording the expected 8H-quino[4,3,2-kl]acridine 11e, cyclisation also led to radical mediated loss of the methyl group to form the unsubstituted 8H-quino[4,3,2-kl]acridine 11a and H-abstraction from the methyl group leading to the benzoazepinoacridine 12. Radical cyclisation of 9-(2-iodoanilino)acridine 16 also gave 8H-quino[4,3,2-kl]acridine 11a. The crystal structure of 11a confirms the 8H tautomer arrangement with intermolecular N8-H...N13 hydrogen bonding and exhibits a polycyclic system that is planar with rms deviation 0.044 A.
