反应详情

0.400 g of trans-4-(4-tert-butoxycarbonylmethylcyclohexyl)benzoic acid (1.26 mmol, 1 eq.) is placed in 8 mL of dichloromethane with stirring, at room temperature, under a nitrogen atmosphere. 0.21 mL of oxalyl chloride (2.51 mmol, 2 eq.) and 2 drops of dimethylformamide are successively added. The reaction medium is stirred for 2 hours and concentrated under vacuum. The tert-butyl trans-4-(4-chlorocarbonylphenyl)cyclohexaneacetate formed is dissolved in 15 mL of acetone and placed under nitrogen. The mixture is cooled in an ice bath and 0.147 g of potassium thiocyanate (1.51 mmol, 1.2 eq.) is added. The reaction mixture is stirred at room temperature for 2 hours. 0.669 g of 2-[(3R,6S/3S,6R)-5,5-dimethylhexahydro-1′H-spiro[1,3-dioxane-2,2′-pentalen]-5′-yl]acetohydrazide (2.37 mmol, 1.89 eq.) dissolved in 10 mL of acetone is then added and the mixture is refluxed for 16 hours. The reaction medium is diluted with dichloromethane and washed three times with water. The organic phase is dried over sodium sulfate and concentrated under vacuum. The residue is chromatographed on silica gel, eluting with a mixture of ethyl acetate and heptane in a 1/2 ratio. After triturating in ethanol, 0.286 g of tert-butyl (trans-4-{4-[(5-{[(3R,6S/3S,6R)-5-ethoxyoctahydropentalen-2-yl]methyl}-1,3,4-thiadiazol-2-yl)carbamoyl]phenyl}cyclohexyl)acetate is obtained.

1. stirringThe reaction medium is stirred for 2 hours
2. concentrationconcentrated under vacuum