A Facile Synthesis ofN ²-Protected L-2,3-Diaminopropanoic Acid

Studies on the Mechanism of 1,2-Dihydropyrazin-2-one Ring Formation from Dipeptidyl Chloromethyl Ketone and Its Chemical Properties: Immediate Deamination during Catalytic Hydrogenation

“…N a -tert-Butyloxycarbonyl(Boc)-Lys(Z)-OH and N aBoc-Orn(Z)-OH were prepared by generally known procedures. 7) N a -Boc-Gln-OH and N a -Boc-Asn-OH were treated with bis(trifluoroacetoxy)-iodobenzene (BTIB) [8][9][10][11] in DMFwater in the presence of pyridine to transform the amide of side chain into amine. 8) The amino function was protected with benzyloxycarbonyl (Z) group by treating with 4-(benzyloxycarbonyloxy)phenyl dimethylsulfonium (Z- group of the dipeptidyl chloromethyl ketone was removed by HCl-dioxane and the resulting H-Xaa(Z)-Xaa(Z)-CH 2 Cl hydrochloride salt was treated under reflux conditions in either acetonitrile (CH 3 CN) or methanol (MeOH) to form the 1,2-dihydropyrazin-2-one derivatives (1)(2)(3)(4).…”

“…Thin-layer chromatography (TLC) was carried out on Silica gel 60 F254 (Merck Japan, Ltd) and compounds were visualized by ultraviolet at either 254 nm or 365 nm when an aromatic (benzene or 1,2-dihydropyrazin-2-one) ring was present, by ninhydrin spray, or ninhydrin plus 25% HBr/acetic acid (AcOH) spray when free amino or Boc-, Z-protected amino groups were present. Rf Orn; Boc-Dap(Z)-OH or Boc-Dab(Z)-OH was prepared from Boc-Asn-OH or Boc-Gln-OH (1.0 eq), BTIB [8][9][10][11] (1.5 eq), pyridine (2.0 eq) and Z-DSP (1.3 eq)], triethylamine (Et 3 N: 16.4 mmol) and isobutyl chloroformate (IBCF: 16.4 mmol) in tetrahydrofuran (THF: 50 ml) at Ϫ15°C. The reaction mixture was stirred at 5°C overnight.…”

Synthesis of Derivatives of ω-Isocyanato-α-methylamino, ω-Ureido-α-methylamino, and Nα-Methyl-α, ω-diamino Acids

“…4,125.5,126.5,127.3,127.9,128.2,129.5,137.9,141.0,144.1 (arom. ),156.6 (CO urethane 5,124.6,126.1,126.6,127.2,127.7,128.9,137.1,140.7,143.6 (arom. ),158.4 (CO urethane N -Methyl-N -(N-morpholinylcarbonyl)-L-2,3-diaminopropionyl-L-phenylalanine amide (11, C 18 …”

Synthesis of Ureido-Linked Glycosylated Amino Acids from N α-Fmoc-Asp/Glu-5-oxazolidinones and Their Application to Neoglycopeptide Synthesis

“…Their method involves in situ generation of sugar isocyanates through a multistep procedure and usage of diamino propionic acid, which is expensive or prepared through another lengthy protocol. [5] On the other hand, Burger et al synthesized these compounds through the reaction of isocyanates of hexafluoro acetone (HFA)-protected a-hydroxy acids with sugar amines.…”