108194-78-1Relevant articles and documents
RIBONUCLEOSIDES OF 3-AMINO- AND 3,5-DIAMINOPYRAZOLE-4-CARBOXYLIC ACID AND THEIR OPEN-CHAIR ANALOGUES: SYNTHESIS AND REACTIONS
Spassova, Maria K.,Holy, Antonin,Masojidkova, Milena
, p. 1512 - 1531 (2007/10/02)
Bis(trimethylsilyl) derivative of ethyl 3-aminopyrazole-4-carboxylate (VI) and tris(trimethylsilyl) derivative of ethyl 3,5-diaminopyrazole-4-carboxylate (VII) on reaction with 2,3,5-tri-O-benzoyl-D-ribofuranosyl chloride and subsequent debenzoylation afforded the respective β-D-ribofuranosyl derivatives VIIIa and Xa.Their alkaline hydrolysis led to 1-(β-D-ribofuranosyl)-3-aminopyrazole-4-carboxylic acid (VIIIc) and 1-(β-D-ribofuranosyl)-3,5-diaminopyrazole-4-carboxylic acid (Xb).The esters VIIIa and Xa were not ammonolysed under normal conditions.Contrary to nucleosidation of the silyl derivatives VI and VII, sodium salt of ethyl 3-aminopyrazole-4-carboxylate was alkylated with 4-chloromethyl-2,2-dimethyl-1,3-dioxolane (XI) or 5-(p-toluenesulfonyloxy)-1,3-dioxane (XVIIb) to give a mixture of the N-isomeric derivatives XIIIa, XIXa and XIIa, XVIIIa, respectively; sodium salt of the 3,5-diamino derivative V reacted with these synthons under formation of the corresponding compounds XIIIb and XXa.Subsequent alkaline and acid hydrolysis of XIIa and XIIIb gave the open-chain analogs of nucleosides XV and XVI.The N-(1,3-dioxan-5-yl) derivatives XVIIIc and XXc resisted acid hydrolysis, giving rise only to carboxylic acids XVIIIb and XXb.
