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

• reaction with 10b at room temperature. In the presence of heat the iminophosphorane intermediate I leads to the formation of the product 3-ethoxy-1,2,4-benzothiadiazine 1,1-dioxide 13 (Scheme 3). However, in all other cases we did not carry out the reactions at room temperature for isolation of the

• -one 1,1-dioxide can further be alkylated at the 4-position, following a literature procedure, to give the bioactive RSV inhibitors. Biologically active 1,2,4-benzothiadiazine 1,1-dioxide derivatives. Retrosynthesis analysis of RSV inhibitors. Preparation of 3-ethoxy-1,2,4-benzothiadiazine 1,1-dioxide