Iodine-Catalyzed, Multicomponent, One-Pot Synthesis of 5-Aryl-5,8-dihydrotetrazolo[1,5-a]pyrimidine-7-carboxylic Acids

Abstract

A series of 5-aryl-5,8-dihydrotetrazolo[1,5-a]pyrimidine-7-carboxylic acids (4) were synthesized from 5-aminotetrazole, pyruvic acid, and aromatic aldehydes in one pot in the presence of I₂ with moderate to good yields. Operational simplicity, mild reaction conditions, and ecofriendly procedure make this novel protocol a promising alternative for the fusion of tetrazolopyrimidines. The structures of the products were proved by ¹H and ¹³C NMR spectroscopy, liquid chromatography–mass spectrometry, and elemental analysis.

Keywords:

• Dihydrotetrazolopyrimidine
• molecular iodine
• multicomponent reactions
• pyruvic acid

Notes

^a Reaction conditions:1 (2 mmol), 4-bromobenzaldehyde (2 mmol), 2 (2 mmol), I₂ (0.4 mmol), solvent 2 mL.

^b Isolated yield.

^c Reaction was conducted without iodine.

^d The reaction mixture was solidified in 10 min without solvent.

^e 20 mol% of Et₃N was added.

^f n(5-AT):n(4-bromobenzaldehyde):n(pyruvic acid) = 1.2:1:1.

^a Reaction conditions: 1 (2 mmol), 4-bromobenzaldehyde (2 mmol), 2 (2 mmol), solvent 2 mL, and refluxing temperature.

^b Isolated yield.

^a Reaction conditions: 1 (2 mmol), 2 (2 mmol), aromatic benzaldehyde (2 mmol), AcOEt (2 mL), I₂ (0.3 mmol, 15 mol%), and temperature (78 °C).

^b Isolated yield.