Oligonucleotide mimics having nitrogen-containing linkages

A method for forming a covalent linkage comprising the steps of

• (a) providing synthons having structures:
• (b) contacting said synthons for a time and under reaction conditions effective to form a covalent linkage having formula —CH=N—;
• wherein:
• RN1 and RN2 are, independently, amine protecting groups, or together form an amine protecting group;
• and
• RA1 and RA2 are, independently, hydrogen, aryl, a protected carbonyl, or a group having the formula:
• {N(RN)—O—A—CH2}r where r is 1-100;
• each A is, independently, RS—X(T—L)—RS;
• N—RN;
• C(O);
• a single bond;
• or (CH2)m where m is 1-5;
• each RN is, independently, H, an amine protecting group or T—L;
• each RS is, independently, a single bond or alkyl having 1 to about 12 carbon atoms;
• each T is, independently, a single bond, a methylene group or a group having structure II:
• —[CR1R2]n—B—[CR1R2]o—[D]p—[N(RN)]q—
• II
• where:
• D is C(O), C(S), C(Se), C(R1)(N3R4), CH2R1, CHR1R2, or NR3R4;
• B is a single bond, CH=CH, C≡C, O, S or NR4;
• each R1 and R2 is independently selected from the group consisting of hydrogen, alkyl or alkenyl having 1 to about 12 carbon atoms, hydroxy- or alkoxy- or alkylthio-substituted alkyl or alkenyl having 1 to about 12 carbon atoms, hydroxy, alkoxy, alkylthio, amino and halogen;
• R3 and R4, independently, are H, —T—L, alkyl having I to about 10 carbon atoms;
• alkenyl having 2 to about 10 carbon atoms;
• alkynyl having 2 to about 10 carbon atoms;
• aryl having 7 to about 14 carbon atoms;
• heterocyclic;
• a reporter molecule;
• or an RNA cleaving group;
• or
• R3 and R4, together, are cycloalkyl having 3 to about 10 carbon atoms or cycloalkenyl having 4 to about 10 carbon atoms;
• n and o, independently, are zero to 5;
• q is zero or 1;
• p is zero to about 10;
• each L is, independently, a nucleosidic base, an amino acid side chain, an aromatic hydrocarbon, a heterocycle moiety containing nitrogen, sulfur, and/or oxygen;
• a carbohydrate, a drug, a reporter molecule;
• an RNA cleaving group;
• and
• each X is, independently, N or CH, or
• X and T, together, form an aromatic moiety, a pentose, a hexose, or a deoxy derivative of a pentose or a hexose.