Polycycles and peptidomimetics

Rigid Polycycles and Peptidomimetics from Carbohydrate Synthons... 

Thymidine dimers in which the natural phosphodiester linkage has been replaced by a 2,5-disubstituted tetrazole ring have been synthesized and have been incorporated into oligodeoxynucleotides <02HCA2847>. The synthesis of mono- and bis-3-substituted thymidine derivatives with a polycyclic tetrazole linker (l,5-bis(tetrazol-5-yl)-3-oxapentane) has been reported <02TL1901>. a-Methylene tetrazole-based peptidomimetics were synthesized for inhibition studies of HIV protease <02JCS(P1)172>. A catalytic amount of tetrazole was found to be useful in the syntheses of symmetrical P,P -dialkyl partial esters of methylenebisphosphonic acid from the corresponding acid chloride via a facile two-step, one-... 

Hanessian, S., and Auzzas, L. (2008) The practice of ring constraint in peptidomimetics using bicyclic and polycyclic amino acids. Acc. Chem. Res. 41, 1241-1251. 

In the present context, we are currently studying peptidomimetic polycyclic structures derived from the thioredoxin reductase active site [56,57], which consist of a domain of peptidic nature containing the sequence for the recognition and of a domain of non-peptidic nature. In the present case, this last domain is formed by an unnatural amino acid of the size (i.e. isosteric) of a bi- or tri-peptide that can undergo cis— trans photoisomerization. Such isomerization induces conformational changes in... 

Other reactions that have been applied in the Ugi postmodification strategy are the aza-Wittig reaction [80-84] and copper-catalyzed processes [85, 86], More recently, Domling and coworkers have developed a new approach for the synthesis of polycyclic compounds via Ugi MCR followed by a Pictet-Spengler reaction [87-89]. In 2011, apro-tocol for the rapid access to quinolin-2-(l//)-one scaffold was reported by a sequential 4-component Ugi-Knoevenagel condensation [90]. Hulme et al. have introduced a one-pot, two-step protocol for large-scale production of libraries of novel peptidomimetic-like fcM-pyrrolidinone tetrazoles via the Ugi-3CR-azide reaction of tethered keto ester methyl... 

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