TY - JOUR A1 - Li, Peng A1 - Wu, Yongqi A1 - Zhang, Tingting A1 - Ma, Chen A1 - Lin, Ziyun A1 - Li, Gang A1 - Huang, Haihong T1 - An efficient and concise access to 2-amino-4H-benzothiopyran-4-one derivatives JF - Beilstein Journal of Organic Chemistry PY - 2019/// VL - 15 SP - 703 EP - 709 SN - 1860-5397 DO - 10.3762/bjoc.15.65 PB - Beilstein-Institut JA - Beilstein J. Org. Chem. UR - https://doi.org/10.3762/bjoc.15.65 KW - 2-amino-4H-benzothiopyran-4-ones KW - addition–elimination KW - scale-up synthesis KW - sulfinyl group N2 - A highly efficient and convenient protocol was developed to access 2-amino-4H-benzothiopyran-4-ones through a process of conjugated addition–elimination. The sulfinyl group was proved to be the optimum leaving group by thorough investigations on the elimination of sulfide, sulfinyl, and sulfonyl groups at the 2-position of benzothiopyranone. Most 2-aminobenzothiopyranones were obtained in good to excellent yields under refluxing in isopropanol within 36 h. This method is base-free and the substrate scope in terms of electronic properties of the substituents of the benzothiopyranone is broad. The ten grams scale-up synthesis of the representative compounds 4a and 4d was implemented to show the practical application of this reaction, which afforded the corresponding compounds in good yields and excellent chemical purity without requiring column chromatographical purification. ER -