Facile synthesis of benzothiadiazine 1,1-dioxides, a precursor of RSV inhibitors, by tandem amidation/intramolecular aza-Wittig reaction

• Krishna C. Majumdar and
• Sintu Ganai

Beilstein J. Org. Chem. 2013, 9, 503–509, doi:10.3762/bjoc.9.54

• yields and high purity, which is the core moiety of RSV inhibitors. Keywords: benzothiadiazine-3-one 1,1-dioxide; 3-ethoxy-1,2,4-benzothiadiazine 1,1-dioxide; intramolecular aza-Wittig reaction; sultam; Introduction Sultams have gained popularity in the scientific community especially among synthetic

• and medicinal chemists, because this basic moiety is present in many natural products and biologically active substances [1][2][3][4][5][6][7][8]. Especially, benzothiadiazine-3-one 1,1-dioxide and its derivatives possess potential activity, including hypoglycemic [9], anticancer and anti-HIV activity

• intermediates. We have also demonstrated the conversion of the products 13 to the 2-substituted benzothiadiazine-3-one 1,1-dioxide 15 by hydrolysing 13 with ethanolic HCl. The benzothiadiazine-3-one 1,1-dioxide derivatives 15c,e,h were obtained in excellent yields from the compounds 13c,e,h (Scheme 4). These 2