Dicyclohexylcarbodiimide → Ethyl cyclopentanecarboxylate

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

To a solution of cis-2-(3-methylbutylamino)-cyclopentanecarboxylic acid ethyl ester (53.5 mg, 0.237 mmol) in N,N-dimethylformamide (3.0 mL) was added (7-methanesulfonylamino-1,1-dioxo-1,4-dihydro-1λ6-benzo[1,2,4]thiadiazin-3-yl)-acetic acid (prepared as described in Example 1j, 157.4 mg, 0.472 mmol) and a 1.0 M solution of N,N′-dicyclohexylcarbodiimide in dichloromethane (0.47 mL, 0.47 mmol). After stirring at 25° C. for 12 h, the mixture was diluted with dichloromethane and the precipitated N,N′-dicyclohexylurea byproduct was removed by filtration. The filtrate was concentrated and dried in vacuo to afford the crude product, cis-2-[2-(7-methanesulfonylamino-1,1-dioxo-1,4-dihydro-1λ6-benzo[1,2,4]thiadiazin-3-yl)-acetyl]-(3-methylbutyl)amino]-cyclopentanecarboxylic acid ethyl ester, which was used in the next step without further purification. LC-MS (ESI) calcd for C23H34N4O7S2 542.19, found 543.2 [M+H+].

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