The 2-amidinylindole-3-carbaldehydes 1 are the key starting materials for the preparation of three classes of carbolines 2, 6 and 7 in which the pyridine ring is characterised by a different substitution patterns. The carbolines 2 which are functionalized with an amino group in position 2, were obtained directly by heating 1 in presence of SiO2. The condensation of amidines 1 with arylmethylketones afforded unsaturated ketones 5 which on heating were transformed into 2,9-dialkyl-3-aroyl-9H-pyrido[2,3-b]indoles 7. Instead, prolonged reaction of amidines 1 with arylmethylketones in t-BuOH/t-BuOK gave 2-aryl-9H-pyrido[2,3-b]indoles 6. (C) 2000 Elsevier Science Ltd.
2-Amidinylindole-3-carbaldehydes: Versatile synthons for the preparation of α-carboline derivatives / E. Erba, M. L. Gelmi, D. Pocar. - In: TETRAHEDRON. - ISSN 0040-4020. - 56:51(2000), pp. 9991-9997.
2-Amidinylindole-3-carbaldehydes: Versatile synthons for the preparation of α-carboline derivatives
E. ErbaPrimo
;M. L. GelmiSecondo
;D. PocarUltimo
2000
Abstract
The 2-amidinylindole-3-carbaldehydes 1 are the key starting materials for the preparation of three classes of carbolines 2, 6 and 7 in which the pyridine ring is characterised by a different substitution patterns. The carbolines 2 which are functionalized with an amino group in position 2, were obtained directly by heating 1 in presence of SiO2. The condensation of amidines 1 with arylmethylketones afforded unsaturated ketones 5 which on heating were transformed into 2,9-dialkyl-3-aroyl-9H-pyrido[2,3-b]indoles 7. Instead, prolonged reaction of amidines 1 with arylmethylketones in t-BuOH/t-BuOK gave 2-aryl-9H-pyrido[2,3-b]indoles 6. (C) 2000 Elsevier Science Ltd.Pubblicazioni consigliate
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