- STEREOSPECIFIC SYNTHESIS OF ISOMERIC 4-SUBSTITUTED 9-(2,3-DIHYDROXYBUTYL)ADENINES
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Reduction of ethyl 2,3-O-isopropylidene-D-tartrate with sodium borohydride afforded (4S,5S)-2,2-dimethyl-1,3-dioxolane-4,5-dimethanol (Va) which was benzoylated to give monobenzoyl derivative Vd and further transformed into p-toluenesulfonyl derivative Ve.Reaction of the compound Ve with sodium salt of adenine followed by methanolysis gave 2,3-O-isopropylidene derivative Vf which on acid hydrolysis afforded 9-(2S,3S)-(2,3,4-trihydroxybutyl)adenine (Ia).The enantiomer IIa was obtained from 3,4-O-isopropylidene-D-mannitol via (4R,5R)-2,2-dimethyl-1,3-dioxolane-4,5-dimethanol (VIa) using the same procedure.Reaction of compounds Vf and VIf with p-toluenesulfonyl chloride afforded 4-O-p-toluenesulfonyl derivatives Vg and VIg.These compounds were also obtained from Va and VIa via di-p-toluenesulfonyl derivatives Vc and VIc by reaction with sodium salt of adenine.Treatment of compounds Vg and VIg with sodium iodide gave 4-iodo derivatives Vh and VIh which on reaction with tri-n-butyltin hydride, followed by acid hydrolysis, afforded enantiomeric threo-2,3-dihydroxybutyl derivatives Ib and IIb.Compounds Vg and VIg on treatment with sodium azide, subsequent catalytic hydrogenation of the intermediates Vj and VIj and acid hydrolysis afforded enantiomeric threo-9-(4-amino-2,3-dihydroxybutyl)adenines (Ic, IIc).Reaction of methyl threo-3-phenylglycerate (VIIb) with acetone, followed by reduction with lithium aluminum hydride, gave 2,2-dimethyl-4-phenyl-1,3-dioxolane-5-methanol (VIIIb) which was converted by reaction with p-toluenesulfonyl chloride, condensation with sodium salt of adenine and acid hydrolysis into 9-(RS)-threo-(3-phenyl-2,3-dihydroxypropyl)adenine (I, IId).Methyl ester of D-eritadenine (IXb) was transformed into 2,3-O-isopropylidene derivative XIa which on reduction with sodium borohydride afforded the alcohol XIb.Its acid hydrolysis gave 9-(2R,3S)-erythro-(2,3,4-trihydroxybutyl)adenine (IIIa); tosylation of compound XIb, successive treatment with sodium iodide and tri-n-butyltin hydride and acid hydrolysis afforded 9-(2R,3S)-erythro-(2,3-dihydroxybutyl)adenine (IIIb).The enantiomers IVa and IVb were obtained analogously from L-eritadenine.The racemic derivative Ib + IIb was prepared from (RS)-threo-2,3-dihydroxybutyric acid via p-toluenesulfonyl derivative of racemic 2,2,4-trimethyl-1,3-dioxolane-5-methanol (IIIc) by reaction of sodium salt of adenine followed by acid hydrolysis.
- HOLY, Antonin
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p. 173 - 189
(2007/10/02)
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