Regioselective quinazoline C2 modifications through the azide–tetrazole tautomeric equilibrium

• Dāgs Dāvis Līpiņš,
• Andris Jeminejs,
• Una Ušacka,
• Anatoly Mishnev,
• Māris Turks and
• Irina Novosjolova

Beilstein J. Org. Chem. 2024, 20, 675–683, doi:10.3762/bjoc.20.61

• : aromatic nucleophilic substitution; azide–tetrazole equilibrium; 4-azido-2-sulfonylquinazolines; quinazolines; sulfonyl group dance; Introduction The quinazoline core is a privileged structure with a wide range of applications. Quinazoline derivatives exhibit a broad spectrum of biological activities

• azide–tetrazole equilibrium of product 12a was initiated, revealing a singular form present in all solvents. Despite attempts to increase the amount of the azide form with the increase of the temperature in NMR experiments [27], no observable alteration in the tautomeric equilibrium was observed. FTIR

• the aromatic nucleophilic substitution of 2-azido-4-sulfonylquinazoline 12a or by performing three subsequent SNAr reactions starting from 2,4-dichloroquinazoline 7 in a one-pot procedure [28] (Scheme 9, Table 2). The resulting products exist in an azide–tetrazole equilibrium in solution, but in solid

Synthesis, effect of substituents on the regiochemistry and equilibrium studies of tetrazolo[1,5-a]pyrimidine/2-azidopyrimidines

• Elisandra Scapin,
• Paulo R. S. Salbego,
• Caroline R. Bender,
• Alexandre R. Meyer,
• Anderson B. Pagliari,
• Tainára Orlando,
• Geórgia C. Zimmer,
• Clarissa P. Frizzo,
• Helio G. Bonacorso,
• Nilo Zanatta and
• Marcos A. P. Martins

Beilstein J. Org. Chem. 2017, 13, 2396–2407, doi:10.3762/bjoc.13.237

• theory (DFT) for energetic and molecular orbital (MO) calculations. Keywords: 5-aminotetrazol; azide–tetrazole equilibrium; 2-azidopyrimidine; β-enaminones; tetrazolo[1,5-a]pyrimidine; trifluoromethylatedtetrazolo[1,5-a]pyrimidines; Introduction Tetrazolo[1,5-a]pyrimidines have attracted attention in

• 1960s and 1970s reported the existence of an azide–tetrazole equilibrium in many heterocyclic systems, namely tetrazolopyridines, tetrazolopyridazines, tetrazolopyrimidines, tetrazoloazines, and tetrazolopurines. Both tetrazole and azide have different chemical properties. Among other factors, the

• nature of the substituents, solvent, temperature, and physical state of the compound (solid state or solution) are the properties that have the most influence on the azide–tetrazole equilibrium [20][21][22][23][24][25][26][27][28]. A comprehensive understanding of the azide–tetrazole equilibrium is of