C2-arylacylation of 2H-benzothiazoles with methyl arenes via Selectfluor oxidation

A Novel PIFA/KOH Promoted Approach to Synthesize C2-arylacylated Benzothiazoles as Potential Drug Scaffolds

“…: 138–140 °C; 1 H NMR (500 MHz, CDCl 3 ) δ 8.56 (dd, J = 8.0, 1.0 Hz, 2H), 8.12 (d, J = 9.0 Hz, 1H), 7.67 (t, J = 7.5 Hz, 1H), 7.57 (t, J = 8.0 Hz, 2H), 7.43 (d, J = 2.5 Hz, 1H), 7.20 (dd, J = 9.0, 2.5 Hz, 1H), 3.95 (s, 3H); 13 C NMR (125 MHz, CDCl 3 ) δ 185.21, 164.70, 159.84, 148.61, 139.16, 135.26, 133.68, 131.20, 128.46, 126.51, 117.63, 103.49, 55.89. These spectroscopic data correspond to the reported data in reference [ 36 ].…”

“…: 167−169 °C; 1 H NMR (500 MHz, CDCl 3 ) δ 8.67 (dd, J = 8.5, 5.5 Hz, 2H), 8.11 (d, J = 9.5 Hz, 1H), 7.43 (d, J = 2.0 Hz, 1H), 7.27–7.20 (m, 3H), 3.94 (s, 3H); 13 C NMR (125 MHz, CDCl 3 ) δ 183.35, 167.27, 165.23, 164.50, 159.84, 148.48, 139.10, 134.02 (d, J = 8.8 Hz), 126.43, 117.71, 115.64 (d, J = 22.5 Hz), 103.41, 55.89. These spectroscopic data correspond to the reported data in reference [ 36 ].…”

“…: 159–161 °C; 1 H NMR (500 MHz, CDCl 3 ) δ 8.98 (d, J = 2.0 Hz, 1H), 8.61 (dd, J = 8.0, 0.5 Hz, 2H), 8.47 (dd, J = 9.0, 2.5 Hz, 1H), 8.39 (d, J = 9.0 Hz, 1H), 7.74 (t, J = 7.5 Hz, 1H), 7.61 (t, J = 8.0 Hz, 2H); 13 C NMR (125 MHz, CDCl 3 ) δ 191.14, 172.44, 157.19, 146.61, 137.14, 134.59, 134.26, 131.41, 128.75, 126.24, 122.08, 118.86. These spectroscopic data correspond to the reported data in reference [ 36 ].…”

“…In recent years, PIFA has received significant attention as a mild, low-toxic, and selective reagent in organic synthesis, which can also be used as an effective alternative to toxic, heavy metal-based oxidants, and expensive organometallic catalysts [ 33 , 34 , 35 ]. In line with our continuous efforts to extend the C2-functionalization methods for 2H -benzothiazoles [ 36 , 37 , 38 , 39 , 40 ], herein we report a novel, convenient, and efficient PIFA/KOH method which synergistically promotes the C2-arylacylation of 2H -benzothiazoles with aryl methyl ketones, affording a wide variety of 2-arylacylated products with good yields. Our process also has the advantages of mild reaction conditions and being transitional metal-free.…”

Gold‐Catalyzed Regioselective Oxyfluorination/Oxydifluorination vs. Diketonization of Phthalimido‐Protected Propargylamines with Selectfluor

“…When NFSI (1.5 equiv) was used as fluorinating agent, only the hydrated product 2 a was isolated under the same reaction conditions (Table 1, entry 15). Surprisingly, the prevalent formation of the α,α-difluoro β-phthalimido ketones 4 a could occur when the gold(III) species PicAuCl 2 or NaAuCl 4 • 2H 2 O were employed as the catalytic system (Table 1, entries [16][17][18][19][20][21][22]. Under the presence of the Au[III] catalyst the 3 a/4 a ratio depended on the quantity of Selectfluor (Table 1, entries 17-21), the reaction temperature (Table 1, entries 19-21) and on the feature of the reaction medium (Table 1, entries 21-23).…”