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ChemicalBook CAS DataBase List 5-Methoxyisatin
39755-95-8

5-Methoxyisatin synthesis

10synthesis methods
Using water as solvent, 5-methoxyaniline reacted with chloral hydrate and hydroxylamine hydrochloride at 90 ℃ for 3.5h to obtain p-methoxyisonitrosoacetanilide in 95% yield. After hydrolysis, 5-methoxyisatin was obtained in 88% yield by cyclization at 92℃ with concentrated H2SO4 (75%).
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Yield:39755-95-8 88%

Reaction Conditions:

with sulfuric acid in water at 70 - 80; for 1.25 h;

Steps:

2) 5-Methoxy-isatin

Concentrated sulfuric acid (176 mL) containing 5 mL of water was warmed to 70 0C and N-(2-hydroximino-acetyl)anisidine (25 g, 0.13 mol) was added portionwise over 1 h maintaining the temperature between 70-80 0C. After complete addition the mixture was refluxed at 80 0C for 15 minutes. Then mixture was poured into 500 g of ice and 800 mL of cold water. The black precipitate was collected by vacuum filtration, washed with cold water to pH 7 and dried on air to give 21.78 g (88 % yield) of 5-methoxy-isatin. mp (exp.) = 201-205 0C (mp [2] = 204-204.5 0C). Spectrum NMR 1 (CDCl3, δ, ppm, J, Hz): 3.74 (s, 3); 6.84 (d, 1, J =8.6); 7.06 (s, 1); 7.17 (dd, 1H, J =1.0, J =2.5); 10.86 (s, 1).

References:

Zaryanova, Ekaterina V.;Lozinskaya, Nataly A.;Beznos, Olga V.;Volkova, Maria S.;Chesnokova, Nataly B.;Zefirov, Nikolay S. [Bioorganic and Medicinal Chemistry Letters,2017,vol. 27,# 16,p. 3787 - 3793] Location in patent:supporting information

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