ChemicalBook CAS DataBase List Ramelteon Impurity 6

Ramelteon Impurity 6 synthesis

11synthesis methods

Product Name:Ramelteon Impurity 6
CAS Number:221530-38-7
Molecular formula:C13H15NO2
Molecular Weight:217.26

1092507-02-2 Synthesis

(R)-2-(2,6,7,8-tetrahydro-1H-indeno[5,4-b]furan-8-yl)acetic acid

1092507-02-2
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221530-38-7
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Yield:221530-38-7 94%

Reaction Conditions:

Stage #1: (S)-2-(2,6,7,8-tetrahydro-1H-indeno[5,4-b]furan-8-yl)acetic acidwith chloroformic acid ethyl ester;triethylamine in dichloromethane at -10 - 5;
Stage #2: with ammonia in dichloromethane at 0 - 5; for 1 h;

Steps:

6

A solution of (85)-l,2,6,7-tetrahydro-8/f-indeno[5,4-δ]furan-8-yl)acetic acid (35.0 gr, 0.1605 mol) in 350 ml of dichloromethane was cooled to between -10⁰C. Triethylamine (19.25 gr, 0.1905 mol) was added dropwise to the reaction mixture, and the obtained reaction mixture was maintained at 0⁰C. The reaction mixture was cooled to -10⁰C and ethyl chloroformate (19.95 gr, 0.1838 mol) was added dropwise to the reaction with cooling, which was then stirred for 2 hours at 0-5⁰C. Then, the reaction mixture was quenched in 550 ml of 2-5 % ammonia solution in dichloromethane at 0-5⁰C,. The reaction mixture was stirred for an hourl at 0-5⁰C. The solvent was distilled out under vacuum at 40 -45⁰C and 245 ml of water and sodium bicarbonate (8.75 gr) were added. 2-[(8S)-1, 6,7, 8-tetrahydro-2/f-indeno[5,4- δ]furan-8-yl]acetamide was isolated by filtration and washed with water. Yield: 94%. Purity: 99.79%.

References:

WO2010/45565,2010,A1 Location in patent:Page/Page column 33-34

196597-78-1 Synthesis