ChemicalBook CAS DataBase List 8-Chloro-5,6-dihydro-11H-benzo[5,6]cyclohepta[1,2-b]pyridin-11-one

8-Chloro-5,6-dihydro-11H-benzo[5,6]cyclohepta[1,2-b]pyridin-11-one synthesis

9synthesis methods

Product Name:8-Chloro-5,6-dihydro-11H-benzo[5,6]cyclohepta[1,2-b]pyridin-11-one
CAS Number:31251-41-9
Molecular formula:C14H10ClNO
Molecular Weight:243.69

3-[2-(3-Chlorophenyl)ethyl]-2-pyridinecarbonitrile

31255-57-9

31251-41-9

General procedure for the synthesis of 8-chloro-5,6-dihydro-11H-benzo[5,6]cyclohepta[1,2-b]pyridin-11-one from 3-(3-chlorophenylethyl)pyridine-2-carbonitrile: 8-chloro-5,6-dihydro-11H-benzo[5,6]cyclohepta[1,2-b]pyridin-11-one (10 g) obtained in step C was dissolved in trifluorosulfonic acid (80 ml) and the reaction was stirred at 60 °C for 1 hour. Subsequently, aqueous 6N hydrochloric acid (80 ml) was added slowly and dropwise at room temperature. The reaction mixture was refluxed for 1 hour and poured into ice water. The reaction solution was neutralized with 50% aqueous sodium hydroxide, the precipitate precipitated was separated, washed with water and recrystallized by solvent mixture of isopropanol/water (3:1) to afford the target product 8-chloro-5,6-dihydro-11H-benzo[5,6]cyclohepta[1,2-b]pyridin-11-one. The mother liquor was concentrated and the residue was washed sequentially with water and chloroform to afford additionally 8-chloro-5,6-dihydro-11H-benzo[5,6]cyclohepta[1,2-b]pyridin-11-one (9.4 g, yield 94%).1H NMR (MeOD-d4) δ: 3.3-3.4 (m, 2H), 3.4-3.5 (m, 2H), 7.5 (m, 2H), 8.1-8.2 (m, 2H), 8.7 (d, 1H), 8.9 (d, 1H).

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Yield:31251-41-9 94%

Reaction Conditions:

Stage #1:3-[2-(3-chlorophenyl)ethyl]-2-pyridine-carbonitrile with trifluorormethanesulfonic acid at 60; for 1 h;
Stage #2: with hydrogenchloride in water at 20; for 1 h;Heating / reflux;

Steps:

3.D
The title compound of Step C (10 g) above was dissolved in trifluorosulfonic acid (80 ml) and stirred at 60⁰C for 1 h. At rt 6 N aqueous HCl (80 ml) was dropwise added. The reaction was refluxed for 1 h and subsequently, poured on ice. After neutralization with 50% aqueous NaOH the precipitate was separated, washed with water and recrystallized from isopropanol/water (3.1) affording the title compound. The mother liquor was concentrated and the residue washed with water and chloroform to afford additional title compound (9.4 g; 94 %).¹HNMR δ (MeOD-Ci₄) 3.3-3,4 (m, 2H), 3.4-3.5 (m, 2H)₅ 7.5 (m, 2H), 8.1-8.2 (m, 2H), 8.7 (d, IH), 8.9 (d, IH)

References:

ALANTOS PHARMACEUTICALS, INC. WO2006/116157, 2006, A2 Location in patent:Page/Page column 56-57

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