TABLE 3.

Synthesized TCPs with nucleotide and/or internucleotide linkage (p) modifications

^7mG ppp N1pN2 N⁷-methylguanosine Series 3-A				^7mG_m ppp N1pN2 N⁷-methyl-3′-O-methylguanosine Series 3-B
TCP	N1	P	N2	TCP	N1	p	N2
1-1A	A_m	PDE	G	1-2A	A_m	PDE	G
3-1A	D_m	PDE	G	3-1B	D_m	PDE	G
				3-2B12	D_m	PSDE (D1+D2)	G
3-3A	A_LNA	PDE	G	3-3B	A_LNA	PDE	G
3-4A1	A_LNA	PSDE (D1)	G
3-4A2	A_LNA	PSDE (D2)	G
3-5A	A_LNA	PDE	U	3-5B	A_LNA	PDE	U
				3-6B1	^6mA_m	PSDE (D1)	G
				3-6B2	^6mA_m	PSDE (D2)	G
				3-7B1	A_m	PSDE (D1)	G
				3-7B2	A_m	PSDE (D2)	G
3-8A1	A_f	PSDE (D1)	G
3-8A2	A_f	PSDE (D2)	G
3-9A	A_f	PDE	U	3-9B	A_f	PDE	U
3-10A	A_m	PDE	G_m	3-10B	A_m	PDE	G_m
3-11A	A_m	PDE	U	3-11B	A_m	PDE	U
3-12A	^6mA_m	PDE	A	3-12B	^6mA_m	PDE	A
3-13A	^6mA_m	PDE	U	3-13B	^6mA_m	PDE	U
				3-14B	A_m	PDE	A
3-15A	G_m	PDE	G	3-15B	G_m	PDE	G

(A) Adenosine; (A_m) 2′-O-methyladenosine; (^6mA_m) N⁶-methyl-2′-O-methyladenosine; (A_f) 2′-Fluoroadenosine; (A_LNA) LNA-adenosine; (G) guanosine; (G_m) 2′-O-methylguanosine; (D_m) 2′-O-methyl-2,6-diaminopurine nucleoside; (U) uridine; (PDE) phosphodiester; (PSDE) phosphorothioate diester; (D1) diastereomer 1; (D2) diastereomer 2.

Novel trinucleotide mRNA capping reagents: improved synthetic route and efficient cotranscriptional incorporation in mRNA