L-Proline, ethyl ester → Pyrrolidinium, 1-(1,3-dithiol-2-ylidene)-2-(ethoxycarbonyl)-, perchlorate

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Reaction Steps

To 30 ml of tetrahydrofuran, 1.4 g of proline ethyl ester was dissolved, and 2.0 g of 2-methylthio-1,3-dithiolium perchlorate was gradually added under stirring at room temperature. The mixture was stirred at room temperature for 1 hour, and the precipitated crystals were collected by filtration and recrystallized from methanol-ethyl ether, whereby 2.1 g (yield: 76%) of 1-(1,3-dithiol-2-ylidene)-2-ethoxycarbonylpyrrolidinium perchlorate (Compound No. 41) was obtained as crystals having a melting point of from 113° to 114° C.

Provenance & Evidence