Water-Promoted Regiospecific Azidolysis and Copper-Catalyzed Azide–Alkyne Cycloaddition: One-Pot Synthesis of 3-Hydroxy-1-alkyl-3-[(4-aryl/alkyl-1H-1,2,3-triazol-1-yl)methyl]indolin-2-ones

Abstract

An efficient, eco-friendly, base free, one-pot, sequential protocol was developed for epoxide azidolysis and copper-catalyzed azide-alkyne cycloaddition using water as the solvent for the synthesis of 3-hydroxy-1-alkyl-3-[(4-aryl/alkyl-1H-1,2,3-triazol-1-yl)methyl]indolin-2-ones. The optimized reaction conditions have been generalized in the case of aromatic as well as aliphatic alkyne partners to afford good yields and high regioselectivity.

One‐pot two‐step synthesis of fused thiazinofuranone linked geminal bis 1,2,3‐triazole hybrids and their in vitro cytotoxic screening

“…Delighted by this and based on the protocols developed for the preparation of bis triazoles from α, α-diazidoketones using Huisgen cycloaddition method [46] and preparation of different geminal bis and tris triazoles from 2,2-diazido-3-oxobutanoate [47], synthesis of thiazinofuranone-triazole hybrid (3) was attempted by treating 2 with the phenylacetylene (4a) in the presence of CuI in water [48] for 12 h at room temperature which furnishes the desired product 6,6-bis(4…”

“…Therefore, in situ generated organic azides are strongly recommended. Feldman et al [50], Odlo et al [51], Kumar [48], and others reported the preparation of 1,4-disubstituted 1,2,3-triazoles in one pot without isolating the organic azide intermediate. Prompted by these protocols we attempted synthesis of thiazinofuranone-triazole hybrid 3 in one pot without isolating the intermediate 2.…”

“…After evaporation of ethyl acetate the crude product was purified by coloumn chromatography using hexane and ethyl acetate mixture. A mixture [45,48] of 5-acetyl-4-hydroxy1, 3-thiazine (1 equiv), iodine (6 equiv), sodium azide (7 equiv), sodium bicarbonate (10 equiv), and 5 ml of water was refluxed for 8 h. Thereafter, the reaction mixture allowed to attaining room temperature and the pH of the solution is adjusted to 7 by adding dilute HCl and then copper iodide (0.24 equiv) and appropriate alkynes (2.4 equiv) were added and stirred for 12-19 h at RT and was quenched with sodium thiosulphate (Na 2 S 2 O 3 ). Then, a small amount of ice-cold water is added and extracted with ethyl acetate.…”

H2O‐Mediated Epoxide Ring‐Opening with Concomitant C–S Bond Formation: A One‐Pot Method to 3‐Hydroxy‐oxindolino‐dithiocarbamates as Cytotoxic Agents

“…For instance, Hajra and co‐workers utilized indole as a nucleophile for regioselective ring‐opening of spiro‐epoxide‐oxindoles to access 3,3′‐bisindoles . A water‐mediated regiospecific spiro‐epoxide ring‐opening by using sodium azide as nucleophile was reported by Kumar and co‐workers for the synthesis of cytotoxic triazolo‐indolinones (Scheme ) . Zang and co‐workers have also reported spiro‐epoxide ring‐opening with ammonia .…”

“…Various, nucleophiles such as indole, phenol, ammonia, azides, anilines, and cyanides have been reported for the electrophilic activation of epoxide ring‐opening. Herein, we report the regioselective epoxide ring‐opening by employing dithiocarbamate as a nucleophile for the formation of 3‐hydroxy‐oxindolino‐dithiocarbamates.…”