Simple and Highly Efficient Catalytic Thiocyanation of Aromatic Compounds in Aqueous Media

Abstract

Two simple, mild, and efficient procedures for the thiocyanation of N-heterocycles, substituted anilines (electron-rich and electron-deficient), and N-substituted aromatic amines at room temperature are reported ( Table 3). The first uses H 2 O 2 as pollution-free oxidant and the second H 5 IO 6 ; both with the reagent potassium thiocyanate in H 2 O as solvent. These procedures provided the target thiocyanates after a short reaction time in good to excellent yields and high regioselectivity.

1-Methyl-3-(2-(Sulfooxy)Ethyl)-1H-Imidazol-3-Ium Thiocyanate as A Novel, Green, and Efficient BrØNsted Acidic Ionic Liquid-Promoted Regioselective Thiocyanation of Aromatic and Heteroaromatic Compounds at Room Temperature

“…In case of 1,2,3,4-tetrahydroquinoline, the reaction did not complete (Table 4, entry 14). Under optimized conditions, when N,N,4-trimethylaniline, N-phenyl acetanilide, anisole, and N,N,N-triphenylamine were used as the substrate, no reaction occurred and the starting materials were recovered after periods of up to 2 days (Table 4, entries [15][16][17][18].…”

Highly Efficient and Practical Thiocyanation of Imidazopyridines Using an N‐Chlorosuccinimide/NaSCN Combination

“…Ethyl 3‐Thiocyanato‐1 H ‐indole‐2‐carboxylate (4y): White solid. 1 H NMR (400 MHz, CDCl 3 ): δ = 9.89 (br.…”

AlCl3-Promoted Thiocyanation of N-Containing Aromatic and Heteroaromatic Compounds Under Solvent-Free Conditions

“…Nitrogen occurs in all living organisms, primarily in amino acids and thus proteins and in the nucleic acids (DNA and RNA). 5 Several methods for the thiocyanation of (hetero)aromatic systems using various reagents such as oxone/NH 4 SCN, 6 N-thiocyanosuccinimde, 7 FeCl 3 /NH 4 SCN, 8 cerric ammonium nitrate (CAN)/NH 4 SCN, 9 Montmorillonite K-10 clay/NH 4 SCN, 10 Poly(4-diacetoxyiodo)styrene (PDAIS)/NH 4 SCN, 11 acidic Al 2 O 3 /NH 4 SCN, 12 HCl/H 2 O 2 /KSCN, 13 Anhydrous AlCl 3 is probably the most commonly-used Lewis acid. This white relative non-toxic powder with LD50 = 3730 mg/kg is moisture-adsorbent.…”