- Quinazoline antifolate thymidylate synthase inhibitors: bridge modifications and conformationally restricted analogues in the C2-methyl series. Marsham, P.R., Jackman, A.L., Hayter, A.J., Daw, M.R., Snowden, J.L., O'Connor, B.M., Bishop, J.A., Calvert, A.H., Hughes, L.R. J. Med. Chem. (1991)