Chemistry of imidazo[2,1-b][1,3,4]thiadiazoles

SNAr versus Buchwald–Hartwig Amination/Amidation in the Imidazo[2,1‐b][1,3,4]thiadiazole Series

“…Imidazo [1,2-b] [1,3,4]thiadiazoles have been used extensively over the last 10 years in the design of bioactive compounds. [1] This heterocycle is found in compounds that have a wide range of promising biological properties such as antitumor, [2] antitubercular, [3] and analgesic characteristics.…”

“…[1] This heterocycle is found in compounds that have a wide range of promising biological properties such as antitumor, [2] antitubercular, [3] and analgesic characteristics. [4] Thus, chemists have been actively pursuing methods for the selective functionalization of the imidazo [2,1-b] [1,3,4]thiadiazole core.…”

“…[1] This heterocycle is found in compounds that have a wide range of promising biological properties such as antitumor, [2] antitubercular, [3] and analgesic characteristics. [4] Thus, chemists have been actively pursuing methods for the selective functionalization of the imidazo [2,1-b] [1,3,4]thiadiazole core. Current strategies for the preparation of substituted imidazo [1,2-b] [1,3,4]thiadiazole derivatives generally involve building the fused aromatic heterocycle by condensation of 2-amino-5-substituted- [1,3,4]thiadiazoles with various α-haloketones or acetophenones.…”

“…[4] Thus, chemists have been actively pursuing methods for the selective functionalization of the imidazo [2,1-b] [1,3,4]thiadiazole core. Current strategies for the preparation of substituted imidazo [1,2-b] [1,3,4]thiadiazole derivatives generally involve building the fused aromatic heterocycle by condensation of 2-amino-5-substituted- [1,3,4]thiadiazoles with various α-haloketones or acetophenones. [5][6][7][8][9][10][11][12][13] This route has the advantage of forming the two fused rings with the desired substituents in the appropriate positions within a limited number of steps.…”

“…[14][15][16][17][18][19][20][21][22][23][24][25][26][27] A major drawback, however, is the need for strongly acidic conditions, which severely restrict its compatibility. Additionally, the unavailability of starting materials and their complex preparations decrease the attractiveness of using the imidazo [2,1-b] [1,3,4]thiadiazole core in large chemistry or medicinal chemistry programs.…”