Synthesis and Crystal Structures of Diaryl Thioethers and Aryl Benzyl Thioethers Derived from Thiosalicylic Acid

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Reaction of thiosalicylic acid and iodobenzene or 1-fluoro-2-nitrobenzene in the presence of two equiv. of K2CO3 in acetone–water afforded the according diaryl thioethers 1 and 2 bearing carboxyl groups. Treatment of thiosalicylic acid with benzyl bromide-type compounds under similar reaction conditions gave aryl benzyl thioethers 3–8 in excellent yields. Moreover, reactions of thiosalicylic acid and benzyl bromide in the presence of excess K2CO3 led to isolation of compound 9 (Leka et al. in Acta Cryst E69:o285–0286, 2013) through further esterification of the carboxyl group. Crystal structures of 2, 5–7 and 9 (Leka et al. in Acta Cryst E69:o285–0286, 2013), along with their spectroscopic properties are reported. Weak hydrogen-bonding interactions exist in compound 2 and isomers 5–7. Compounds 2 and 7 crystallize in the monoclinic space group P21/n and C2/c, respectively, with a = 12.04(3), b = 7.311(19), C=14.22(4) A, β = 93.94(3)°, and Z = 4 for 2, and a = 14.934(13), b = 5.116(5), C=33.76(3) A, β = 91.523(12)°, and Z = 8 for 7. The unit cell of 5 has triclinic P-1 symmetry with the cell parameters a = 5.4334(14), b = 7.7787(19), C=16.488(4) A, α = 76.601(3)°, β = 86.078(3)°, γ = 70.772(3)°, and Z = 2 for 5. Compound 6 crystallizes in the orthorhombic space group Pbca with a = 15.1881(12), b = 7.3288(6), C=23.7366(19) A, and Z = 8. Reactions of thiosalicylic acid and a series of aryl- or benzyl halides in the presence of K2CO3 in acetone–water resulted in the formation of according diaryl thioethers and aryl benzyl thioethers in excellent yields.