Reaction of PEG-bound sulfonic acid with thionyl chloride formed the difunctionalised PEG-supported sulfonyl chloride, which was treated with α-hydroxyketones, followed by treatment with 2-aminopyridine in the presence of potassium carbonate efficient to afford imidazo[1,2-a]pyridines in good yields with a facile work-up procedure.
TeuladeJ.C., GrassyG., EscaleR., and ChapatJ.P., J. Org. Chem., 1981, 46, 1026.
14.
HandE.S., and PaudlerW.W., J. Org. Chem., 1980, 45, 3738.
15.
GuildfordA.J., TometzkiM.A., and TurnerR.W., Synthesis, 1983, 987.
16.
MontgomeryJ.A., and SecristJ.A., In Comprehensive heterocyclic chemistry, eds KatritzkyA.R., ReesC.W., and PottsK.T., Pergamon: Oxford, 1984; Vol. 5, p. 607.
17.
VarmaR.S., and KumarD., Tetrahedron Lett, 1999, 40, 7665.
18.
KatagiriN., and KatoT., J. Heterocycl. Chem., 1984, 21, 407.
19.
KondoT., KotachiS., OginoS., and WatanabeY., Chem. Lett, 1993, 1317.
20.
DaveyD.D., J. Org. Chem., 1987, 52, 1863.
21.
GalonsH., BergeratI., FarnouxC.C., and MiocqueM., Synthesis, 1982, 1103.
22.
KnolkerH.-J., BoeseR., and HitzemannR., Chem. Ber., 1990, 123, 327.
23.
SinghS.P., NaithaniR., and PrakashO., J. Indian Chem. Soc., 1998, 75, 770.
24.
KatritzkyA.R., QiuG.Q., LongQ.H., HeH.Y., and SteelP.J., J. Org. Chem., 2000, 65, 9201.
25.
XieY.-Y., ChenZ.-C., and ZhengQ.-G., Synthesis, 2001, 2075.