ChemicalBook CAS DataBase List 4-Chloro-7-methylisatin

4-Chloro-7-methylisatin synthesis

4synthesis methods

Product Name:4-Chloro-7-methylisatin
CAS Number:61258-72-8
Molecular formula:C9H6ClNO2
Molecular Weight:195.6

Acetamide, N-(5-chloro-2-methylphenyl)-2-(hydroxyimino)-

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Yield:-

Reaction Conditions:

with sulfuric acid at 70 - 75; for 0.5 h;

Steps:

2

To a mixture of chloral hydrate (0.39 kg, 2.36 mole) in water (3.6 L) was charged sodium sulfate (1.22 kg). A mixture of 5-chloro-2-methylaniline (0.40 kg, 2.15 mole), water (1.84 L) and concentrated HCl (0.22 kg) were added to the aqueous chloral hydrate mixture followed by a solution of hydroxylamine hydrochloride (0.488 kg) in water (0.96 L). The mixture was heated to 70-75° C. and stirred for a minimum of 6 h until less than 10% 5-chloro-2-methylaniline remains by TLC. The mixture was cooled to room temperature, filtered and the cake washed with water (2×1.2 L). The wet solid (5-chloro-2-methylisonitrosoacetanilide) was added to hot sulfuric acid (2.94 kg) at 70-75° C. and stirred for a minimum of 30 mins until less than 2% starting material remains by TLC. The mixture was cooled and quenched into ice water (6.4 L) over 40 mins. The precipitated solids are filtered, reslurried in water (2.4 L) and filtered. The wet cake was washed with heptane (3×0.80 L). The solid was dried (65° C., 10 mm Hg, 24-48 h) to give 4-chloro-7-methyl isatin in 63% overall yield from the starting aniline.

References:

US2006/58532,2006,A1 Location in patent:Page/Page column 9