Biginelli and Hantzsch-Type Reactions Leading to Highly Functionalized Dihydropyrimidinone, Thiocoumarin, and Pyridopyrimidinone Frameworks via Ring Annulation with β-Oxodithioesters

Abstract

An efficient and highly convergent route to dihydropyrimidinones (DHPMs) and hitherto unreported dihydropyridopyrimidinones has been developed by one-pot, three-component cyclocondensation of aromatic aldehydes, β-oxodithioesters, and urea/6-amino-1,3-dimethyluracil in the presence of recyclable SiO2-H2SO4. On the other hand, salicylaldehyde, β-oxodithioester, and urea reacted under similar conditions to afford the 3-aroyl/heteroaroyl-2H-chromen-2-thiones in high yields instead of Biginelli product. The attractive feature of this approach is the synthesis of three important bioactive heterocyclic frameworks from the same β-oxodithioester under the similar reaction conditions, making this new strategy highly useful in diversity-oriented synthesis (DOS).

Similarity and Competition between Biginelli and Hantzsch Reactions: an Opportunity for Modern Medicinal Chemistry

“…In this case, urea was not recovered in the product structure as it spontaneously acted as reaction promoter. [91] Again, what is appealing about this approach is the possibility to create, with the same experimental setup, diverse functionalized heterocyclic scaffolds, which makes this strategy useful in diversity-oriented synthesis.…”

Efficient synthesis of polyfunctionalized thiophene-2,3-diones and thiophen-3(2H)-ones using β-oxodithioesters

“…However, the reaction of 1h with chloroacetic anhydride was messy producing several unidentifiable products. The characterization data ( 1 H, 13 C NMR, IR and HRMS) obtained for 3a-g were given in supplementary file and the ORTEP view of the single crystal X-ray analysis of 3b (CCDC 1402849) with atomic numbering is shown in Figure 3.…”

β-Oxodithioesters

“…7 (J) The treatment of pyridine substituted β-oxodithioester with 2-bromoacetophenone led to the formation of highly substituted indolizine in moderate to good yield. The reaction was performed in chloroform in the presence of catalyst DBU/p-chloranil.…”