Synthesis and Thermal Studies of Fused Azaisocytosine Congeners

Ethyl 2-[4-oxo-8-(R-phenyl)-4,6,7,8-tetrahydroimidazo[2,1-c][1,2,4]triazin-3-yl]acetates (1–6) belonging to fused azaisocytosine congeners have been synthesised for the purposes of thermal studies according to efficient synthetic approaches previously patented and published [2 ,3 (link)]. The structures of molecules 1–6 have been confirmed by ¹H-NMR/¹³C-NMR spectra and elemental analysis, and established on the basis of the performed ¹³C, ¹H HMBC and HMQC correlations for the ethyl ester of 2-(4-oxo-8-phenyl-4,6,7,8-tetrahydroimidazo[2,1-c][1,2,4]triazin-3-yl)acetic acid (1) [3 (link)]. The purity and homogeneity of all the compounds intended for thermal studies (1–6) have been previously evaluated under reaction and the purification conditions employed. All these ones have been obtained and described [3 (link)] as homogenous, pure, crystalline solids with sharp melting points and microanalyses within ±0.4 percent of the calculated values. They have been reported to reveal not only enhanced anticancer effects in malignant human multiple myeloma cells (MM1R, MM1S) but also antiproliferative activities against human tumours of the breast (T47D) and cervix (HeLa) [3 (link)]. In addition, their mode of anticancer action and very low toxicities towards normal human skin fibroblasts have been previously documented [3 (link)].