ChemicalBook CAS DataBase List 5-Methyl-2-aminobenzothiazole

5-Methyl-2-aminobenzothiazole synthesis

13synthesis methods

Product Name:5-Methyl-2-aminobenzothiazole
CAS Number:14779-17-0
Molecular formula:C8H8N2S
Molecular Weight:164.23

333-20-0

108-44-1

14779-17-0

GENERAL METHOD: A solution of 3-methylaniline (2 mmol) in acetonitrile (15 ml) was added to a solution of potassium thiocyanate (8 mmol) in acetonitrile (15 ml). Subsequently, 0.06 g (30 mol% BF3) of BF3/SiO2 nanoparticles was added to the mixture and the mixture was placed in an ice salt bath and mechanically stirred for 30 min. Then, a solution of bromine (4 mmol, 0.2 ml) in acetonitrile (3 ml) was slowly added through a dropping funnel, controlling the rate of addition to ensure that the reaction temperature did not exceed 0 °C. After complete addition of bromine, the reaction mixture was continued to be stirred at room temperature for 4 h, during which the progress of the reaction was monitored by TLC. Upon completion of the reaction, the mixture was poured into water and heated to 70 °C on a steam bath followed by thermal filtration to remove the catalyst. The catalyst was washed with acetone and recycled for reuse. The filtrate was neutralized with 10% NaOH solution and the precipitate was collected, dried and recrystallized from ethanol (10 ml) to give 2-amino-5-methylbenzothiazole. The product was characterized by physical properties and spectral data (including melting point, FT-IR, 1H NMR and 13C NMR) and confirmed by comparison with known standards. Spectral data of the selected products: 6-bromo-1,3-benzothiazol-2-amine (2e) as a yellow solid; yield = 93%; melting point = 202-204 °C (literature value 203 °C); FT-IR (KBr) ν/cm-1: 3315, 3012, 2835, 1580, 1476, 1261, 920, 742, 512; 1H NMR ( 400MHz, CDCl3) δ ppm: 5.44 (s, 2H, NH2), 7.4-7.5 (d, 2H, Ar-H), 7.71 (s, 1H, Ar-H); 13C NMR (100MHz, DMSO-d6) δ ppm: 119, 120.9, 125.15, 126.07, 133.1, 152.15, 167.75. 152.15, 167.75.

333-20-0
466 suppliers
$13.50/100G

108-44-1 Synthesis

108-44-1
379 suppliers
$9.00/1g

14779-17-0
117 suppliers
$62.00/100mg

Yield: 92%

Reaction Conditions:

Stage #1:potassium thioacyanate;1-amino-3-methylbenzene with nano-BF₃/SiO₂ in acetonitrile for 0.5 h;Cooling with ice;
Stage #2: with bromine in acetonitrile at 0 - 20; for 5 h;

Steps:

General procedure for the synthesis of 2-aminobenzothiazoles catalyzedby nano-BF₃/SiO₂
General procedure: A solution of substituted aniline (2 mmol) in acetonitrile (15 ml) was added to a solution of KSCN (8 mmol) in acetonitrile (15 ml). Then, 0.06 g (30 mol % BF3) of nano-BF₃/SiO₂ was added to the mixture, then was placed in a freezing mixture of ice and salt and mechanically stirred for 30 min. Then, bromine (4 mmol, 0.2 ml) in acetonitrile (3 ml) as solvent was added from a dropping funnel at such a rate that the temperature never rose beyond 0°C. After all the bromine was added at 60 min, the solution was stirred for 4 h at room temperature. The progress of the reaction was monitored by TLC. Then, the mixture was poured into water with stirring and the mixture was heated to 70°C on a steam bath and filtered hot to remove the catalyst and the recovered catalyst was washed with acetone and reused in the reaction. The filtrate was neutralized with 10 % NaOH solution and the precipitate was collected on a filter, dried and recrystallized from ethanol (10 ml) to afford the corresponding products. All of the 2-aminobenzothiazole products were identified by physical and spectroscopic data as reported below, compared and contrasted with authentic samples. Spectral data for selected products 6-Bromo-1,3-benzothiazol-2-amine (2e) Yellow solid; Yield = 93 %; m.p. =202-204°C; (m.p. = 203°C), FT-IR (KBr)/t(cm^-1): 3315, 3012, 2835,1580, 1476, 1261, 920, 742, 512. ¹H NMR (400 MHz, CDCl₃)/d ppm: 5.44 (s, 2H, NH2) 7.4-7.5 (d, 2H, Ar-H), 7.71 (s, 1H, Ar-H); ¹³C NMR/(100 MHz, DMSO-d6)/d ppm: 119, 120.9, 125.15, 126.07, 133.1, 152.15, 167.75.

References:

Naeimi, Hossein;Heidarnezhad, Arash [Research on Chemical Intermediates,2016,vol. 42,# 12,p. 7855 - 7868]