3.01 – Pyrazoles

Solid phase polyamine linkers-their utility in synthesis and the preparation of directed libraries against trypanothione reductase

Synthesis of 4-(pyrazol-5-yl)-1,2,4-triazole-3-thiones

Polyamines and polyamine conjugates display a diverse range of important biological functions, ranging from antibiotics to immunosuppressants and glutamate receptor antagonists. For these reasons, polyamines provide an excellent template/scaffold for combinatorial chemistry. In this paper we present methods for the solid-phase immobilisation of polyamines for use in synthetic and combinatorial chemistry and describe how they have been employed in the preparation of a number of important polyamine conjugates and polyamine libraries. Thus, we have designed, synthesised and utilised a number of polyamine linkers for both solution and resin screening combinatorial application.

Synthetic methods for polyamine linkers and their application to combinatorial chemistry

A series of2-(5-amino-3-arylpyrazol-1-yl)-3-methylquinoxalines (2a–d)has been synthesized by the condensation of2-hydrazino-3-methylquinoxaline (1) with substitutedbenzoylacetonitriles and converted into the corresponding3,4-diaryl-1-(3-methylquinoxalin-2-yl)-4,8-dihydro-1H
-pyrazolo[3,4-e
][1,4]thiazepin-7(6H
)-ones(7a–d) and2-(3-aryl-4,5,6,7-tetrahydro-5-alkyl/aryl-1H
-pyrazolo[3,4-d
]pyrimidin-1-yl)-3-methylquinoxalines(8a–e).

Studies on the Synthesis and Cyclization Reactions of2-(5-Amino-3-arylpyrazol-1-yl)-3-methylquinoxalines

A new general and efficient synthesis of imidazo[4,5-c]pyrazole derivatives

A new general and efficient synthesis of imidazo[4,5-c]pyrazoles ( 5 ) is reported. The key step of this synthetic procedure is the intramolecular cyclodehydration of 5 -alkylamino- 4 -nitrosopyrazoles ( 4 ), which affords the title compounds ( 5 ) in good yields.

Bruno Lumachi

Papers

A new general and efficient synthesis of imidazo[4,5-c]pyrazole derivatives

A New General and Efficient Synthesis of Imidazo(4,5-c)pyrazole Derivatives.