Synthesis, characterization, and DFT study of a novel pyrido[2',3':4,5]pyrimido[2,1-b][1,3]thiazines via Michael addition and intramolecular cyclization. - Huwaimel B; Gomha SM; Ebaid MS; Abouzied AS; Riyadh SM; Ahmed MSM; Zaki MEA; Al-Hussain SA; Hussein WM; El-Reedy AAM (BMC chemistry, 2026)