Fe3O4@SiO2@Methotrexate as efficient and nanomagnetic catalyst for the synthesis of 9-(aryl)thiazolo [4,5-d] [1,2,4]triazolo [1,5-a]pyrimidin-2(3H)-ones via a cooperative anomeric based oxidation: A joint experimental and computational mechanistic study

9-(Aryl)thiazolo [4,5-d] [1,2,4]triazolo [1,5-a]pyrimidin-2(3H)-ones have been efficaciously synthesized in good yields via reaction of aldehydes, 2,4-thiazolidinedione and 3-amino-1,2,4-triazole under the solvent free condition at 100 degrees C by using a catalytic amount (1 mg) of Fe3O4@SiO2@Methotrexate. This reaction proceeded via a cooperative anomeric based oxidation (ABO) pathway. The reaction condition is appropriate due to the easy experimental procedure and product separation. It is a three-component reaction that lets the building of rather complex sulfur including heterocyclic categories by using simple reactants. The competition of reaction mechanisms (both thermodynamically and kinetically) for the formation of 9-phenylthiazolo [4,5-d] [1,2,4]triazolo [1,5-alpha]pyrimidin-2(3H)-one and 5-phenylthiazolo [5,4-e] [1,2,4]triazolo [1,5-alpha]pyrimidin-7(8H)-one is also computationally compared at M06/def2-SVP. The synthesized Fe3O4@SiO2@Methotrexate MNPs catalyst was characterized by several techniques such as FT-IR, EDX, WDX, XRD, FE-SEM, TEM, TGA, DTA, and VSM analyses. The catalyst was recycled and reused in six next runs without any important activity. (C) 2021 Elsevier B.V. All rights reserved.