2-Benzofuransulfonamide(9CI) synthesis

Yield:124043-72-7 76%

Reaction Conditions:

Stage #1: 1-benzofuranewith n-butyllithium in diethyl ether;hexane at -78; for 0.0833333 h;Inert atmosphere;
Stage #2: with N-sulfinyl-O-(tert-butyl)hydroxylamine in diethyl ether;hexane at -78; for 0.333333 h;Inert atmosphere;
Stage #3: with potassium hydroxide in diethyl ether;hexane;lithium hydroxide monohydrate at 60; for 6 h;Inert atmosphere;Reagent/catalyst;Temperature;

Steps:

General procedure for the synthesis of primary sulfonamides 14a-k:

General procedure: To a stirred solution of 13a-k (1.0 equiv.) in anhydrous Et₂O (10.0 mL), was added 2.0 M n-BuLi in hexane (1.2 equiv) at -78 °C under nitrogen. The reaction mixture was stirred at -78 °C for 5 minutes, and then added t-BuONSO (1.2 equiv) in anhydrous Et₂O (1.00 mL) drop wise. The resulting reaction mixture was stirred at -78 °C for 20 minutes added 2N KOH and stirred at 60 °C for 6 h. The reaction mixture was allowed to warm up to room temperature. The reaction mixture was extracted with EtOAc (3 x 10 mL). Combined organic layers were washed with brine (10.0 mL), dried over Na₂SO₄ and concentrated. The obtained crude residue was purified by column chromatography by eluting with 0 to 60% ethyl acetate/hexane to afford the pure primary sulfonamides 14a-k in 68-77% yield

References:

Tummanapalli, Satyanarayana;Bodige, Srinu;Gulipalli, Kali Charan;Endoori, Srinivas;Medaboina, Srinivas;Mallidi, Kalyani [Tetrahedron Letters,2022,vol. 97,art. no. 153781] Location in patent:supporting information