1202-31-9Relevant articles and documents
Solution phase synthesis of imidazo[1,2-b]pyrazol-2-one, an interesting 5,5-fused heterocyclic ring system
Blass, Benjamin E.,Srivastava, Anil,Coburn, Keith R.,Faulkner, Amy L.,Janusz, John J.,Ridgeway, James M.,Seibel, William L.
, p. 619 - 621 (2004)
The solution phase synthesis of a series of imidazo[1,2-b]pyrazol-2-ones, a fused 5,5-ring system, based on diverse set of hydrazino acids and malononitriles is described. The method involves formation of 5-aminopyrazoles followed by intra-molecular cyclodehydration.
New pyrazole containing bicarboxylic α-amino acids: Mimics of the cis amide bond
De Luca, Lidia,Falorni, Massimo,Giacomelli, Giampaolo,Porcheddu, Andrea
, p. 8701 - 8704 (2007/10/03)
A series of novel optically active α-amino acids, containing a pyrazole ring, which can be regarded as building blocks for peptidomimetics, have been prepared starting from readily available α-amino acids. The synthetic strategy employed allows the regio- and stereoselective preparation of 1,3- or 1,5-substituted pyrazolyl rings. The pyrazole containing peptidomimetics can be considered as analogues of peptides with a cis amide bond.
Synthesis of fused 1,2,5-triazepine-1,5-diones and some N2- and N3-substituted derivatives: Potential conformational mimetics for cis-peptidyl prolinamides
Lenman, Morag M.,Lewis, Arwel,Gani, David
, p. 2297 - 2311 (2007/10/03)
The synthesis of a new fused 1,2,5-triazepine-1,5-dione heterocycle, which is expected to mimic structural features of cis-peptldyl prolinamides, is described. The required parent heterocycle, corresponding to cis-glycy-(2S)-prolinamide, has been prepared in good yield by the cyclisation of N-(2-bromoacetylprolyl)-hydrazine which is itself generated in situ from the bromoacetyl proline methyl ester. Analogues corresponding to cis-(2R)-alanyl- and cis-(2S)-alanyl-(2S)-prolinamide have been similarly prepared from the appropriate N-(2-bromopropionyl)proline methyl esters and hydrazine hydrate where the cyclisation step, involving the displacement of bromide, has been shown to occur with inversion of configuration at C-2 of the propionyl moiety. Acylation at the N-3 position of the triazepine is equivalent to N-terminal acylation of the residue preceding the proline residue in cis-aminoacyl prolinamides. This has been achieved without incident using standard peptide coupling procedures. Extension at the 'C-terminal' has been achieved by preparing elaborated hydrazine precursors which are reacted with suitably activated esters of N-α-halogenoacylprolines, prior to cyclisation, to give the required fused triazepine dione. Thus it is possible to prepare constrained cis-peptidyl prolyl peptide mimetics of defined stereochemistry based upon this new triazepine dione in which all of the non-proline residues can be varied.
