A comparative synthesis of 6-benzyl-2,3-dihydroimidazo[2,1-a]phthalazine and 2H-7-benzyl-3,4-dihydropyrimido[2,1-a]phthalazine

• Published in: Tetrahedron letters Vol. 56; no. 6; pp. 828 - 830
• Main Authors: Munín, Javier, Santana, Lourdes, Uriarte, Eugenio, Borges, Fernanda, Quezada, Elías
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 04-02-2015
• Subjects: Condensation; Cyclization; Derivatives; Imidazophthalazine; Pyrimidophthalazine; Strategy; Synthesis; Synthesis (chemistry); Tetrahedrons; Imidazophthalazine; Synthesis; Cyclization; Pyrimidophthalazine; Condensation
• ISSN: 0040-4039; 1873-3581
• DOI: 10.1016/j.tetlet.2014.12.121

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Two new synthetic strategies have been developed for the synthesis of a new class of cyclophthalazine derivatives. 6-Benzyl-2,3-dihydroimidazo[2,1-a]phthalazine and 2H-7-benzyl-3,4-dihydropyrimido[2,1-a]phthalazine were obtained (i) by intramolecular cyclization of the 2-(aminoalkyl)-4-benzyl-2H-phthalazin-1-one or (ii) by intramolecular cyclization of the corresponding 2-(4-benzylphthalazin-1(2H)-ylideneamino)alcohols previously prepared. The second of the described routes afforded the desired derivatives in high yields.