Novel sulfur and selenium containing bis-α-amino acids from 4-hydroxyproline

The synthesis of new substituted prolines carrying at C-4 a second α-amino acid residue is reported. The amino acid, l-cysteine or l-selenocysteine, is linked to the proline ring through the sulfur or the selenium atom, respectively. The products were prepared with different stereochemistry at C-4, in few and clean high-yielding steps, with suitable protections for solid phase applications. The introduction of both sulfur and selenium atoms at C-4 of the proline ring seems to enhance significantly the cis geometry at the prolyl amide bond

MODIFIED AMINO ACIDS: SYNTHESIS AND APPLICATIONS

Gli obiettivi raggiunti sono: • Sintesi stereoselettiva di β2,3-amminoacidi (2,3-disostituiti) attraverso l'introduzione sulla posizione C-2 di β3-amminoacidi di: 1. Gruppi polari (OH, NH2, CH2OH) 2. Gruppi non polari (CH3, CH2Ph) 3. Deuterio, con completa diteurazione della posizione C-2. • Sintesi di nuovi mimici dell’ aspartame: 1. Sintesi in soluzione di diversi dipeptidi contenenti β-amminoacidi 2,3- disostituiti 2. Studi conformazionali, attraverso dicroismo circolare (CD) e dinamica molecolare, di questi dipeptidi • Sintesi di amminoacidi ‘lipidici’: 1. Introduzione di lunghe catene idrofobiche sulla posizione C-2 di β-alanina 2. Sintesi di peptidi contenenti questo tipo di β-amminoacidi 2,2-disostituiti • Sintesi di α-amminoacidi α,α-disostituiti: 1. Sintesi di peptidi contenenti α-amminoacidi α,α-disostituiti: nuovi ‘cell penetrating peptides (CPPs)

A facile way to thiosulfonic S-esters

Synthesis of thiosulfonic S-esters from thiosulfonyl chloride

Enantiopure b3-amino acids-2,2-d2 via homologation of proteinogenic a-amino acids

A procedure for the synthesis of enantiopure β3-amino acids from proteinogenic α-amino acids, developed by our group a few years ago, has been modified to enable the production of C-2 fully deuterated, C-protected β3-amino acids and, even more important, the synthesis of valuable deuterium labelled N(Boc)-protected chiral synthons, such as 2-aminoalcohols, 2-aminoiodides, and β3-amino nitriles

A new easy conversion of sulfoxides to sulfides

A new reaction for the conversion of sulfoxides to sulfides by boro trifluoride and sodium iodide, both readly available and low cost

Trimethylsilyl tetrafluoroborate a convenient reagent for solvolysis reactions

Conversions of cyclopropyl carbinols and ketones into omoallyl and gamma-substituted ketone derivatives, respectively, are accomplished by trimethylsilyl tetrafluoroborate efficiently under mild condition

Triterpenes from the galls of pistacia palestina

triterpene components from galls produced by pemphigus corniculariu