Scheme for the synthesis of 1,3,5-triazine (s-triazine) derivatives (7, 13 and 18). Regents: (a) p-nitroaniline, K2CO3 in THF, (b) 1-chloro-4-ethylpiperazine, K2CO3, 18-Crown-6 in dry THF (refluxed for 2.5Â h), (c) 1-chloro-4-ethylpiperazine, K2CO3, 18-Crown-6 in dry CH3CN (refluxed for 3Â h), (d) 3-(chloroamino)phenol, K2CO3, 18-Crown-6 in dry CH3CN (refluxed for 3Â h)