Sequential Construction of Complex Pyrrole-Pyrrole or Pyrrole-Pyrazole Systems from 1,2-Diaza-1,3-butadienes

Orazio A. Attanasi; Lucia De Crescentini; Paolino Filippone; Barbara Guidi; Francesca R. Perrulli; Stefania Santeusanio

doi:10.1055/s-1999-2848

Synlett 1999; 1999(9): 1367-1370
DOI: 10.1055/s-1999-2848

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Sequential Construction of Complex Pyrrole-Pyrrole or Pyrrole-Pyrazole Systems from 1,2-Diaza-1,3-butadienes

Orazio A. Attanasi^* , Lucia De Crescentini, Paolino Filippone, Barbara Guidi, Francesca R. Perrulli, Stefania Santeusanio

^*Istituto di Chimica Organica della Facoltà di Scienze, Università di Urbino, Piazza della Repubblica 13, 61029 Urbino, Italy; Fax + 39.07 22.29 07; E-mail: attanasi@fis.uniurb.it

Abstract

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The treatment of cyanoacetic acid hydrazide or ethyl 3-hydrazino-3-oxopropionate with methyl 2-chloroacetoacetate leads to the corresponding hydrazone derivatives. In the presence of sodium carbonate, these compounds react at room temperature with acetoacetanilide or 2,4-pentanedione to give the relevant 1-aminopyrrole rings. In the presence of sodium methoxide, the activated methylene group present on the 1-amino side chain of these heterocycles attacks at room temperature 1,2-diaza-1,3-butadienes affording the respective hydrazonic 1,4-adducts. Under basic conditions, these adducts surprisingly cyclise at room temperature in different way providing pyrrole-pyrrole or pyrrole-pyrazole systems depending on the starting cyano or ethylcarboxylate group, respectively.

hydrazones - 1,2-diazal - 3-butadienes - cyclization - pyrroles - pyrazoles

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