1-Chloroethyl chloroformate → (4-Isopropoxy-3-methyl-phenyl)-[10-(3-methyl-1,2,4-oxadiazol-5-yl)-11-oxa-3,8-diazaspiro[5.5]undecan-3-yl]methanone hydrochloride salt

Beteiligte Stoffe

Reaktionsschritte

A solution of 1-chloroethyl chloroformate (89 μL, 0.80 mmol) in DCE (0.1 mL) was added to a stirred solution of [8-benzyl-10-(3-methyl-1,2,4-oxadiazol-5-yl)-11-oxa-3,8-diazaspiro[5.5]undecan-3-yl]-(4-isopropoxy-3-methyl-phenyl)methanone (67 mg, 0.13 mmol) in DCE (488 μL) under an atmosphere of nitrogen and the reaction mixture was heated to reflux. After 1 hour, an additional aliquot of 1-chloroethyl chloroformate (89 μL, 0.80 mmol) was added and the reaction mixture was heated to reflux for a further 8 hours. After 8 hours, an additional 1-chloroethyl chloroformate (89 μL, 0.80 mmol) was added and the reaction mixture was heated to reflux for a further 15 hours. The excess solvent was removed under reduced pressure and the carbamate intermediate was dissolved in MeOH (2 mL) and heated at reflux for 1 hour. The reaction mixture was cooled to room temperature, filtered and purified by Waters mass directed LC/MS-HPLC: (10-99% ACN/H2O (5 mM HCl)) to afford (4-isopropoxy-3-methyl-phenyl)-[10-(3-methyl-1,2,4-oxadiazol-5-yl)-11-oxa-3,8-diazaspiro[5.5]undecan-3-yl]methanone hydrochloride salt (28 mg, 47%). ESI-MS m/z calc. 414.2. Found 415.7 (M+1)+; Retention time: 1.54 minutes (3 min run).

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