Reactions with Hydrazonoyl Halides 63: Synthesis and Anticancer Activity of Some New 1,3,4-Thiadiazoles, 1,3,4-Selenadiazoles, and 1,2,4-Triazolo[4,3-a]pyrimidines

2,3-Dihydro-1,3,4-thiadiazoles, 2,3-dihydro-1,3,4-selenadiazoles, and triazolino[4,3-a]pyrimidines containing benzoxazole or benzothiazole moieties were prepared from the reaction of each of ethyl 3-aza-3-(benzoxazol-2-ylamino)-2-chloroprop-2-enoate and ethyl 3-aza-3-(benzothiazolo-2-ylamino)-2-chloroprop-2-enoate with each of potassium thiocyanate, potassium selenocyanate, alkyl carbodithioate, and pyrmidine-2-thione derivatives. All the newly synthesized compounds were confirmed by elemental analysis, spectral data, and alternative route synthesis whenever possible. Some of the newly synthesized compounds were screened toward certain cancer tumors. Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file.