title: Facile synthesis of Nalpha-protected-L-alpha,gamma-diaminobutyric acids mediated by polymer-supported hypervalent iodine reagent in water.
abstract: 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.
authors.affiliation: Department of Chemistry, Gunma University, 1-5-1, Tenjin-cho, Kiryu, Gunma 376-8515, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Yamada
authors.forename: H
authors.initials: H
authors.lastname: Urakawa
authors.forename: H
authors.initials: H
authors.lastname: Oku
authors.forename: R
authors.initials: R
authors.lastname: Katakai
mesh_terms: D000596:Amino Acids / Q000138:chemical synthesis / Q000737:chemistry; D020148:Butyric Acid / Q000138:chemical synthesis / Q000737:chemistry; D007455:Iodine / Q000737:chemistry*; D015394:Molecular Structure; D010455:Peptides / Q000138:chemical synthesis / Q000737:chemistry; D011108:Polymers; D011112:Polymyxin B / Q000031:analogs & derivatives* / Q000737:chemistry; D012997:Solvents; D014867:Water / Q000737:chemistry*
chemical_list: D000596:Amino Acids; D010455:Peptides; D011108:Polymers; D012997:Solvents; D014867:Water; D020148:Butyric Acid; C075546:cyclo(diaminobutyryl-diaminobutyryl-phenylalanyl-leucyl-diaminobutyryl-diaminobutyryl-threonyl); D007455:Iodine; D011112:Polymyxin B