Nucleic Acids in Chemistry and Biology

A related but more general route to nucleoside 5-triphosphates or
,-substituted analogues thereof involves
the reaction of an activated nucleoside monophosphate, which is then able to condense with pyrophos-
phate or a pyrophosphate analogue102,103such as methylenebisphosphonate. Among the condensing agents
which have been used widely are DCC to prepare the reactive nucleoside 5-phosphoromorpholidatesand
carbonyl diimidazole(Figure 3.65).34,90,104,105This procedure is well suited to the introduction of isotopic
oxygen into nucleotides in a non-stereochemically controlled fashion, for subsequent use in positional iso-
tope exchange (PIX) studies.
Base and sugar-modified nucleoside 5-triphosphates and 5 -(1-thio)triphosphates(-thiotriphosphates)
are generally more often made in a simple one-pot reaction exploiting the Yoshikawa phosphorylation.
Here a nucleoside-5-phosphorodichloridate (Figure 3.66) is reacted in situ with tetrakis(tributylammo-
nium) pyrophosphate.^106 The resulting cyclic triphosphate formed is then hydrolysed to afford linear triphos-
phates^107 or (1-thio)triphosphates,^99 while hydrolysis by other nucleophiles (e.g.morpholine), results in
-substituted triphosphates (Figure 3.66).
In related methodology developed by Ludwig and Eckstein, the more reactive P(III) reagent, salicyl
chlorophosphite, is used and this allows the preparation of nucleoside 5-triphosphates after final oxidation.^108
Modifications also furnish routes to 5-(1-thio)triphosphates and dithiotriphosphate derivatives,109,110and
Barbara Shaw has used the procedure for the preparation of nucleoside 5 -(1-borano)triphosphates
(-boranotriphosphates)^111 (Figure 3.67).

114 Chapter 3

O

HO R

Cl P O B

X

Cl

O

HO R

P O B

X

O

P

OP

O O

O

O

O

O

HO R

P O B

O

O

X

N P O P

OOO O

O

O

HO R

P O B

O

O

X

O P O P

OOO O

B = Ade, Cyt, Gua, Thy, Ura or modified base

R = OH, H, F;X=O,S

(i)

(iii)

(ii)

Figure 3.66 Syntheses of nucleoside triphosphates and analogues using phosphorus(V) chemistry. Reagents:
(i) tetrakis (tributylammonium) pyrophosphate in DMF; (ii) Et 3 NHHCO 3 ; and (iii) morphiline

O

HO

O P O

O

O

Ade

OH

O

HO

Ade

OH

O

P

O

O

O

P

PhO

PhOO

ADP

O

HO

O P O

O

N

Ade

O OH

O

O

HO OH

Ade

P

O

O

O

P

O

P

O

OOO O ATP

X =^18 O, CH 2 , CF 2 , NH etc.

(i) (iii)

(ii)

(v)

(iv),(v) (iv), (v)

Figure 3.65 Synthesis of nucleoside diphosphates and triphosphates and analogues by P O bond formation.
Reagents: (i) (PhO) 2 POCl in DMF; (ii) DCC, morpholine, pyridine; (iii) tributylammonium phosphate in
DMF; (iv) CDI in pyridine; and (v) tributylammonium pyrophosphate or pyrophosphate analogue in DMF

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