2-AMINO-6-BENZOTHIAZOLOL HCL synthesis

Yield:26278-78-4 75%

Reaction Conditions:

Stage #1: thioureawith hydrogenchloride in ethanol;water; for 0.5 h;
Stage #2: p-benzoquinone in ethanol;water at 25; for 24 h;

Steps:

3.3. Syntheses of 2-amino-6-hydroxybenzothiazole

Thiourea (7.6 g; 0.1 mol) was dissolved in 200 mL of ethanol and then 9 mL of concentrated HCl was added dropwise. After stirring for 30 min, a solution of 1,4-benzoquinone (21.6 g, 0.2 mol) in ethanol (400 mL) was added dropwise and stirring continued for 24 h at 25 °C. Then the solvent was eliminated under reduced pressure. The residual solid was washed with cold ethanol until TLC monitoring showed completion of the reaction. The prepared 2-amino-6-hydroxybenzothiazole hydrochloride salt was dissolved in a small amount of water, filtered, and acidified with HCl to afford 15.2 g (75%) of white crystalline solid. To obtain the 2-amino-6-hydroxybenzothiazole as a free base, the salt was dissolved in deionized water and neutralized by sodium acetate. The product was purified by recrystallization from an ethanol-water mixture to afford straw-colored needles. Mp 263-265 °C, 1 H NMR (DMSO-d6) : (δ; ppm) 5.7 (2H, NH2 ), 6.8-7.3 (3H, Ar-H), 9.4 (1 H, OH) (Figure11); FT-IR [(KBr) νmax /cm1 ], 3308 (OH), 1602 (N-H), 1508 (C-O-H) 1201 (C-O), 1051 (benzothiazole), 817 (C-S), (Figure 12; Supplementary data); MS in amu: 165.1 (Figure 13).

References:

Shahmoradi, Ghasem;Amani, Saeid [Turkish Journal of Chemistry,2018,vol. 42,# 6,p. 1499 - 1517]