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

Abstract

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) Å, β = 93.94(3)°, and Z = 4 for 2, and a = 14.934(13), b = 5.116(5), C=33.76(3) Å, 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) Å, 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) Å, and Z = 8.

Graphical Abstract

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.