ChemicalBook CAS DataBase List 2-Cyano-6-methoxybenzothiazole

2-Cyano-6-methoxybenzothiazole synthesis

12synthesis methods

Product Name:2-Cyano-6-methoxybenzothiazole
CAS Number:943-03-3
Molecular formula:C9H6N2OS
Molecular Weight:190.22

Typical routes to 2-cyano-6-methoxybenzothiazole include the classical Rosenmund-von Braun and Sandmeyer reactions. These methods proceed with low atom economy and require toxic reagents such as KCN, NaCN, Zn(CN)2, or TMSCN, which are also challenging to handle in a large-scale synthesis. Shahmoradi et al. introduced a Cu-catalyzed cyanation of 2-iodo-6-methoxybenzothiazole to synthesize 2-cyano-6-methoxybenzothiazole. K4[Fe(CN)6] was applied as a source of cyanide, and CuI in the presence of N, N N′, N′-tetramethylethylenediamine (TMEDA) was used as part of the catalyst system. 2-Amino-6-methoxybenzothiazole as a starting material was synthesized from p-anisidine as shown below and subsequently converted into 2-iodo-6-methoxybenzothiazole using a simple and efficient one-pot sequential diazotization-iodination method. The one-pot cyanation of 2-iodo-6-methoxybenzothiazole to 2-cyano-6-methoxybenzothiazole was achieved using 0.25 mmol of K4[Fe(CN)6], 0.25 mmol of CuI and 3 mmol of TMEDA in acetonitrile at 160°C. In addition, 1 mmol of mystril trimethyl bromide (MTMAB) was used as a phase transfer agent. The presence of a phase-transfer catalyst is essential for a successful cyanation reaction. Under these conditions, 2-cyano-6-methoxybenzothiazole was produced in a 90% yield[1].

32338-02-6
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$14.00/1g

75318-43-3 Synthesis

4,5-Dichloro-1,2,3-dithiazolium chloride

75318-43-3
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$32.00/100mg

943-03-3
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$9.00/100mg

Yield:943-03-3 64%

Reaction Conditions:

Stage #1:2-bromo-4-methoxyaniline;4,5-dichloro-1,2,3-dithiazolium chloride in dichloromethane at 20; for 1 h;Inert atmosphere;
Stage #2: with 1,8-diazabicyclo[5.4.0]undec-7-ene in dichloromethane at 5 - 40; for 5 h;Inert atmosphere;

Steps:

General procedure for the one-pot, base-mediated, metal free synthesis of 6-substituted 2-c yanobenzothiazoles from monobrominated para -substituted anhlines
General procedure: Appel’s salt and an aniline were allowed to stir in CH2CI2 (DCM) for 1 h at room temperature under a nitrogen atmosphere. The solution was then cooled to below 5 00 and base (preferably DBU orDBN) was added, dropwise over 30 mm, to the stirring solution maintained at 5 00 all under a nitrogen atmosphere. After the addition, the resulting mixture was stirred for 30 mm while allowing it to warm to room temperature, after which it was ref luxed at 40 C for 4 h. Upon cooling to room temperature (rt), ethyl acetate (EtOAc) was added. The reaction mixture was then washed with saturated NH4CIaq solution, and H20. The organic phase was dried over Na2SO4 and concentratedin vacuo. The crude material was purified by silica gel chromatography to provide the corresponding benzothiazoles.

References:

UNIVERSITY OF CAPE TOWN;JARDINE, Moegamat Anwar;RYLANDS, Marwaan WO2019/21202, 2019, A1 Location in patent:Page/Page column 26

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