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ChemicalBook CAS DataBase List Ethyl 5-formyl-2,4-dimethyl-1H-pyrrole-3-carboxylate
2199-59-9

Ethyl 5-formyl-2,4-dimethyl-1H-pyrrole-3-carboxylate synthesis

7synthesis methods
-

Yield:2199-59-9 100%

Reaction Conditions:

with hydrogenchloride in N-methyl-acetamide;(2S)-N-methyl-1-phenylpropan-2-amine hydrate;dichloromethane;trichlorophosphate;

Steps:

80 5-[5-Fluoro-2-oxo-1,2-dihydro-indol-(3Z)-ylidenemethyl]-2,4-dimethyl-1H-pyrrole-3-carboxylic Acid (2-diethylamino-ethyl)-amide

Dimethylformamide (322 g) and dichloromethane (3700 mL) were cooled in an ice bath to 4° C. and phosphorus oxychloride (684 g) was added with stirring. Solid 2,4-dimethyl-1H-pyrrole-3-carboxylic acid ethyl ester (670 g) was slowly added in aliquots over 15 minutes. The maximum temperature reached was 18° C. The mixture was heated to reflux for one hour, cooled to 10° C. in an ice bath and 1.6 L of ice water was rapidly added with vigorous stirring. The temperature increased to 15° C. 10 N Hydrochloric acid (1.6 L) was added with vigorous stirring. The temperature increased to 22° C. The mixture was allowed to stand for 30 minutes and the layers allowed to separate. The temperature reached a maximum of 40° C. The aqueous layer was adjusted to pH 12-13 with 10 N potassium hydroxide (3.8 L) at a rate that allowed the temperature to reach and remain at 55° C. during the addition. After the addition was complete the mixture was cooled to 10° C. and stirred for 1 hour. The solid was collected by vacuum filtration and washed four times with water to give 5-formyl-2,4-dimethyl-1H-pyrrole-3-carboxylic acid ethyl ester (778 g, 100% yield) as a yellow solid. 1H-NMR (DMSO-d6) δ 1.25 (t, 3H, CH3), 2.44, 2.48 (2*s, 2*3H, 2*CH3), 4.16 (q, 2H, CH2), 9.59 (s, 1H, CHO), 12.15 (br s, 1H, NH). MS m/z 195 [M+1].

References:

US2003/216410,2003,A1

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