Some transformations of DL-phenylalanine ortho esters and N-benzyloxycarbonyl-L-phenylalaninal

Abstract

Glycine ortho esters have found a wide use2 in the synthesis of glycyl derivatives of ribonucleosides,2a'b ribonucleotides,20 and ribooligonucleotides.2d_h The application of the ortho ester exchange method which provides the basis of the synthetic approach28 to the above mentioned compounds for amino acids other than glycine has been hampered for a long time by a lack of general method for the preparation of amino acid ortho esters.3

Solid-Phase Synthesis of Peptide Vinyl Sulfones as Potential Inhibitors and Activity-Based Probes of Cysteine Proteases

“…The reaction was carried out smoothly in the presence of NaH at room temperature, generating both the trans isomer (e.g., 5a in Scheme ) as the predominantly major product (>90% as judged by 1 H NMR and HPLC), and the cis isomer, 5b , with acceptable yield (59−78% for 5a + 5b ). No racemization of 5 at its chiral center was observed, as judged by both 1 H NMR and HPLC, in good agreement with previous reports for similar reactions 10a…”

“…Our first task was to synthesize N -fluorenylmethoxycarbonyl (Fmoc)-α-amino aldehydes. They were conveniently synthesized by a well-established, two-step procedure, involving the transformation of N -Fmoc-α-amino acid to the corresponding Weinreb amide, followed by reduction with LiAlH 4 . The N -Fmoc-α-amino acids 1 were first coupled with N , O -dimethylhydroxylamine to give the resulting amides 2 in 80−99% yields, followed by LiAlH 4 reduction at 0 °C to give the aldehydes 3 .…”

2'(3')-O-Glycyl oligoribonucleotides with sequences of the 3'-terminus of glycyl-tRNA: chemical synthesis and properties in partial reactions of protein biosynthesis

“…Synthesis. We have chosen to investigate the synthesis of longer 2,(3,)-D-glycyl oligoribonucleotides for a number of First, ethyl iV-(benzyloxycarbonyl)orthoglycinate is readily available [unlike the protected ortho esters of other amino acids; see Zemlicka and Murata (1976)] and reacts smoothly with unprotected nucleosides to form 2,,3,-0-cyclic ortho esters (Zemlicka & Chládek, 1966). These ortho esters are fully stable in an alkaline medium that is used for the removal of benzoyl groups from aglycons as well as 2chlorophenyl groups from phosphotriesters (Kumar et al, 1982).…”