3,3,5-Trimethylcyclohexanol → 3,3,5-Trimethylcyclohexyl N-benzyloxycarbonyl-L-pyroglutamate

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Reaction Steps

34.2 g (0.13 mol) of N-benzyloxycarbonyl-L-pyroglutamic acid (prepared according to Berichte 97, 2434 [1964] or Annalen 649, 183 [1961]) are added to 150 ml of dimethylformamide, followed by 2 g of dimethylaminopyridine and then 18.48 g (0.13 mol) of 3,3,5-trimethylcyclohexanol (mixture of 90% trans isomer and 10% cis isomer) diluted in 50 ml of dimethylformamide. 26.8 g (0.13 mol) of dicyclohexylcarbodiimide are then run in over a period of about 15 minutes, the reaction medium being kept at +5° C. The mixture is then stirred at room temperature for 24 hours, after which the solvent is evaporated off, the residue is taken up with dilute hydrochloric acid and extraction is carried out with chloroform.

Provenance & Evidence