Synthesis of all four nucleoside-based β-amino acids as protected precursors for the synthesis of polyamide-DNA with alternating α-amino acid and nucleoside-β-amino acids

Catalytic Reductions Without External Hydrogen Gas: Broad Scope Hydrogenations with Tetrahydroxydiboron and a Tertiary Amine

“…In contrast to the deprotection of benzyl ( R )‐(1‐(naphthalen‐1‐yl)ethyl)carbamate where amine‐boron complexation likely occurred, this did not seem to occur in the reduction of TBDMS‐protected 3′‐azido‐3′‐deoxythymidine, Cbz cleavage from the aryl amine, and reduction of the aryl azides. The 1 H NMR data of 46 was consistent with the literature data …”

Synthesis and DNA/RNA Binding Properties of Conformationally Constrained Pyrrolidinyl PNA with a Tetrahydrofuran Backbone Deriving from Deoxyribose

“…Deoxyribonucleoside-derived cyclic β-amino acids have been used in designing nucleobase-containing foldamers, some of which showed promising DNA and RNA binding properties . These foldamers can therefore be regarded as a new class of peptide nucleic acid (PNA). , Our research group had introduced a series of conformationally constrained pyrrolidinyl peptide nucleic acids derived from alternating nucleobase-modified d -proline and cyclic β-amino acids. , A representative member of such pyrrolidinyl PNA is acpcPNA (Scheme ) which carries trans -(1 S ,2 S )-2-aminocyclopentanecarboxylic acid (ACPC) in the backbone. , This acpcPNA showed some distinct properties from DNA and commercial PNA that could be useful for many applications .…”

Glycine-Linked Nucleoside-β-Amino Acids: Polyamide Analogues of Nucleic Acids

“…We decided to avoid the capping step (except after initial nucleoside loading on the resin) after each coupling in the present study to get longer sequences, as we observed that the 3′-NH-trityl functionality of the growing chain was partially acylated resulting in termination of the synthesis after 6–7mer synthesis. The acylation of the 3′NH-trityl group was also observed in solution-phase synthesis of the monomers even with isobutyric anhydride. , The synthesis of 10mer and 12mer mixed base purine/pyrimidine amide-linked oligomers comprising alternate nucleoside-β-amino acids (Figure , 1 – 4 ) and glycine as -α-amino acid was accomplished, and the synthesized sequences are shown in Table (couplings monitored by trityl UV absorbance at 410 nm, SI Experimental, S2–S3). As the capping step after coupling was avoided to get longer sequences, the synthetic purity of the crude oligomers was affected.…”

“…The acylation of the 3′NH-trityl group was also observed in solution-phase synthesis of the monomers even with isobutyric anhydride. 30,33 The synthesis of 10mer and 12mer mixed base purine/pyrimidine amide-linked oligomers comprising alternate nucleoside-β-amino acids ( Figure 2, 1−4) and glycine as -α-amino acid was accomplished, and the synthesized sequences are shown in Table 1 (couplings monitored by trityl UV absorbance at 410 nm, SI Experimental, S2−S3). As the capping step after coupling was avoided to get longer sequences, the synthetic purity of the crude oligomers was affected.…”

“…For the synthesis of mixed base sequences containing purine nucleosides, the use of TFA/TFA:TFMSA also needs to be avoided due to likely depurination in strongly acidic medium. With an aim to achieve complete replacement of phophodiester linkages in mixed pu/py sequences by the charge-neutral amide linkages in sugar-amide backbone, we previously converted nucleosides into NH-trityl protected β-amino acid derivatives , ( 1 – 4 , Figure ). In the present studies, we extend this strategy for the synthesis of oligomer sequences containing only py (C and T) (TRT1) and a mixed pu/py (TRT2) that would give us insight into the orientation selective DNA/RNA binding properties of amide-DNA.…”