AMINO-ACIDS BEARING NUCLEOBASES FOR THE SYNTHESIS OF NOVEL PEPTIDE NUCLEIC-ACIDS

All of the four nucleobases found in DNA have been incorporated in the ir protected form into the 4-position of N-tert-butoxycarbonyl-L-proli ne methyl ester with cis-stereochemistry. An efficient route for the s ynthesis of N-tert-butoxycarbonyl-trans-4-hydroxy-D-proline methyleste r has been developed from which the enantiomers may be synthesized, In addition an efficient synthesis of N-tert-butoxycarbonyl-N-(2-hydroxy ethyl)glycine methyl ester has been achieved and its hydroxy group rep laced with protected nucleobases using the Mitsunobu reaction.