1.The new esters derivatives of betulin and betulinic acid in epidermoid squamous carcinoma treatment - In vitro studies.
Drąg-Zalesińska M1, Wysocka T1, Borska S1, Drąg M2, Poręba M2, Choromańska A3, Kulbacka J4, Saczko J3. Biomed Pharmacother. 2015 May;72:91-7. doi: 10.1016/j.biopha.2015.04.003. Epub 2015 Apr 13.
BACKGROUND: Betulinic acid and betulin are triterpenes with documented cytotoxic properties toward various cell lines. Unfortunately both betulinic acid and its metabolic precursor, betulin, are very poorly soluble in aqueous buffers, thus their bioavailability and bio-distribution are insufficient in terms of medical applications.
2.Synthesis of triamino acid building blocks with different lipophilicities.
Maity J1, Honcharenko D1, Strömberg R1. PLoS One. 2015 Apr 14;10(4):e0124046. doi: 10.1371/journal.pone.0124046. eCollection 2015.
To obtain different amino acids with varying lipophilicity and that can carry up to three positive charges we have developed a number of new triamino acid building blocks. One set of building blocks was achieved by aminoethyl extension, via reductive amination, of the side chain of ortnithine, diaminopropanoic and diaminobutanoic acid. A second set of triamino acids with the aminoethyl extension having hydrocarbon side chains was synthesized from diaminobutanoic acid. The aldehydes needed for the extension by reductive amination were synthesized from the corresponding Fmoc-L-2-amino fatty acids in two steps. Reductive amination of these compounds with Boc-L-Dab-OH gave the C4-C8 alkyl-branched triamino acids. All triamino acids were subsequently Boc-protected at the formed secondary amine to make the monomers appropriate for the N-terminus position when performing Fmoc-based solid-phase peptide synthesis.
3.Facile synthesis of Nalpha-protected-L-alpha,gamma-diaminobutyric acids mediated by polymer-supported hypervalent iodine reagent in water.
Yamada K1, Urakawa H, Oku H, Katakai R. J Pept Res. 2004 Aug;64(2):43-50.
Hofmann rearrangement of Nalpha-Boc-L-Gln-OH mediated by a polymer-supported hypervalent iodine reagent poly[(4-diacetoxyiodo)styrene] (PSDIB) in water afforded Nalpha-Boc-L-alpha,gamma-diaminobutyric acid (Boc-Dab-OH, 1) in 87% yield. Nalpha-Z-derivative (Z-Dab-OH, 2) was prepared with PSDIB in 83% yield. Since the reaction of Nalpha-Fmoc-Gln-OH by this procedure did not proceed because of the insolubility of Fmoc-Gln-OH in aqueous media, we synthesized Fmoc-Dab(Boc)-OH (5) from 2 in 54% yield. Polymyxin B heptapeptide (PMBH) which contains four Dab residues was successfully synthesized in a solution-phase synthesis.
