- Development of N-4,6-pyrimidine-N-alkyl-N'-phenyl ureas as orally active inhibitors of lymphocyte specific tyrosine kinase. Maier, J.A., Brugel, T.A., Sabat, M., Golebiowski, A., Laufersweiler, M.J., VanRens, J.C., Hopkins, C.R., De, B., Hsieh, L.C., Brown, K.K., Easwaran, V., Janusz, M.J. Bioorg. Med. Chem. Lett. (2006)