N4-Boc-cytosin-1-yl acetic acid

Pd-catalyzed C-H functionalization of mandelic acid and α-phenylglycine is reported. We have developed different protocols for the arylation, iodination, acetoxylation, and olefination of these substrates based on two different (Pd(II)/Pd(IV) and Pd(II)/Pd(0)) catalytic cycles. Four crucial features of these protocols are advantageous for practical applications. First, the α-hydroxyl and amino groups are protected with simple protecting groups such as acetates (Ac, Piv) and carbamates (Boc, Fmoc), respectively. Second, these protocols do not involve installation and removal of a directing group. Third, monoselectivity is accomplished. Fourth, no epimerization occurs at the vulnerable α-chiral centers.

The title compound, C(7)H(13)NO(5), was prepared by the condensation of O-(carb-oxy-meth-yl)hydroxyl-amine and (Boc)(2)O (Boc = but-oxy-carbon-yl).In the crystal, mol-ecules are linked by weak inter-molecular N-H⋯O hydrogen bonds.

The present study describes the solid-state conformation of αβ hybrid peptides, Boc-Leu-β3, 3 -Ac6 c-OH, P1; Boc-Leu-β3, 3 -Ac6 c-Leu-β3, 3 -Ac6 c-OMe, P2; and Boc-Leu-β3, 3 -Ac6 c-Leu-β3, 3 -Ac6 c-Leu-OMe, P3. The dipeptide P1 adopts extended conformations, whereas tetrapeptide P2 and pentapeptide P3 favor a helical conformation stabilized by mixed types of C11 /C9 intramolecular hydrogen bonds. In peptide P3, the amino group of β3, 3 -Ac6 c(2) and β3, 3 -Ac6 c(4) residues occupies axial orientation, whereas in P2 it occupies axial and equatorial orientations for residues β3, 3 -Ac6 c(2) and β3, 3 -Ac6 c(4), respectively. The self-assembly of P3 forms channels filled with solvent molecules that present interesting patterns.