January 1974

Document Type


Degree Name



Dept. of Chemistry


Oregon Graduate Center


A general discussion of the syntheses of C-nucleosides is presented. A proposed new reaction type which employs silver (I) in a sulfur extrusion-rearrangement is discussed. Precedent for the new reaction type sought, one of metal, induced sulfur extrusion with concomitant carbon-carbon bond formation between the termini of the sulfur bridge, may be found in the ease of complex formation between metals (e. g. Ag[superscript +1], Hg[superscript +2]) and sulfide sulfur and also in the effective use, in cyclic systems, of Ni[superscript +2] to extrude sulfur with bond formation between the termini of the sulfur bridge. The nature of this new type reaction for the synthesis of C-nucleosides is explored employing 3- (2'-tetrahydrofuranylthio)indole (8b) in reactions with anhydrous silver perchlorate. This study provided 2-(2'-tetrahydrofuranyl)indo1e (10b), a model C-nucleoside. A general mechanism for the silver (I) induced reactions of 3 - (2' - tetrahydropyranylthio)indole (8a) and 3- (2'-tetrahydrofuranylthio)indole (8b) is proposed. It was concluded on the basis of this study that a second "holding" linkage should be introduced prior to reaction with Ag[superscript +1]. Nucleophilic displacement reactions on derivatives of 3-bromopyrazolo[4, 3-d]pyrimidin-7-one (21) and 3-(5-)-bromo-5-(3-)-methyl-4- nitropyrazole (26) employing sulfur nucleophiles are discussed. This study provided 1, 6-dibenzyl-3- (phenylthio)pyrazolo[4, 3-d]pyrimidin-7-one (40) and 3-methyl-4-nitro-5-(2'-tetrahydropyranylthio)pyrazole (36) a model sulfur bridged nucleoside. The reaction of S-(β-D-ribofuranosyl)-5-mercaptouracil (41) with aqueous silver nitrate provided a quantitative yield of the silver salt of 5-mercaptouracil (43). An attempt to synthesize the 2'-0-p,-toluene-sulfonyl derivative of S- [5' - 0. (t-butyldimethylsilyl)- β- D- ribofuranosyl] - 5- mercaptouracil (49) provided the rearrangement, elimination product S- {3'-[5'-(t-butyldimethylsilyloxymethyl)furanyl]} -5-mercaptouracil (50). From this study it was noted that labilizing a ribosyl hydroxyl in the presence of the sulfide sulfur creates the probability of sulfur migration to the carbon bearing the activated hydroxyl. The photolysis of derivatives of D-mannopyrano[cis-1, 2-b]dihydrobenzothiazine (42) in trimethylphosphite as solvent and thiophile are presented. The nature of the interaction between silver (I) and derivatives of D-mannopyrano[cis-1, 2-b]dihydrobenzothiazine (42), especially 6'-0- (t-butyldimethylsilyl)-D-mannopyrano[cis -1,2- b]dihydrobenzothiazine (51), is discussed. From this study it was noted that an N-anhydro "holding" linkage places the nucleophilic nitrogen bridge in proximity for capture of the reactive sugar terminus of the sulfur bridge after lysis by Ag[superscript +1] or photolysis.





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