6865-06-1Relevant academic research and scientific papers
3-Amino-1H-pyrazolopyrimidines and 3-Aminoisothiazolopyrimidines as Precursors of Tricyclic Heteroaromatic Systems Containing a Bridgehead Nitrogen Atom.
Golec, Julian M. C.,Scrowston, Richard M.
, p. 326 - 345 (2007/10/02)
3-Amino-4-methyl-6-phenyl-1H-pyrazolopyrimidine (3a) and 3-amino-4-methyl-6-phenylisothiazolopyrimidine (9a) have been prepared.The former reacts with bromoacetone or 3-bromopentane-2,4-dione, to give tricyclic systems (1a) or (13) containing an extra pyrazole or pyrimidine ring, respectively; in each case the newly formed ring contains a bridgehead nitrogen atom, derived from N-2 of the starting material.With the same reagents, the latter undergoes an interesting ring-opening reaction, for which possible mechanisms are proposed.In contrast, 3-amino-1,2-benzisothiazole does not undergo ring fission under similar conditions, but gives rise to tricyclic compounds containing a bridgehead nitrogen atom.
