Tricyclic Pyrazoles: An Efficient Approach to Cannabinoid Analogues with a Tricyclic Framework Incorporating the Pyrrole and Pyrazole Moieties

Giansalvo Pinna; Gérard A. Pinna; Giorgio Chelucci; Salvatore Baldino

doi:10.1055/s-0032-1316703

Synthesis, Table of Contents

Synthesis 2012; 44(17): 2798-2804
DOI: 10.1055/s-0032-1316703

paper

Tricyclic Pyrazoles: An Efficient Approach to Cannabinoid Analogues with a Tricyclic Framework Incorporating the Pyrrole and Pyrazole Moieties

Giansalvo Pinna*

^aDipartimento di Chimica e Farmacia, Università di Sassari, Via F. Muroni 23/A, 07100 Sassari, Italy, Fax: +39(79)228720 Email: pinlab@uniss.it

,

Gérard A. Pinna

^aDipartimento di Chimica e Farmacia, Università di Sassari, Via F. Muroni 23/A, 07100 Sassari, Italy, Fax: +39(79)228720 Email: pinlab@uniss.it

,

Giorgio Chelucci

^bDipartimento di Agraria, Università di Sassari, Viale Italia 39, 07100 Sassari, Italy

,

Salvatore Baldino

^bDipartimento di Agraria, Università di Sassari, Viale Italia 39, 07100 Sassari, Italy

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Abstract

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Abstract

In this paper we report the synthesis of some new cannabinoid analogues that share with rimonabant, a potent and selective CB₁ antagonist, the 2,4-dichlorophenyl and piperidin-1-yl substituents on the pyrazole and amide nitrogens, respectively. The general synthesis involves the preparation of a cyclic ketone condensed with a pyrrole, followed by Claisen condensation with diethyl oxalate; from here, an aza-annulation reaction with a substituted hydrazine followed by an amidation step complete the synthesis.

Key words

cannabinoids - tricyclic pyrazoles - Friedel–Crafts acylation - Claisen condensation - aza-annulation

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References

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