Hydrochloric Acid → (3S)-8-(3-methylbutylidene)-4-(4-methylpentanoyl)-1-thia-4-azaspiro[4.5]-decane-3-carboxylic acid

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Reaction Steps

In 8 ml of methylene chloride are dissolved 0.79 g of (3S)-8-(3-methylbutylidene)-1-thia-4-azaspiro[4.5]decane-3-carboxylic acid and 1.20 ml of triethylamine. Into the solution thus obtained are dropwise added a solution of isocaproyl chloride (prepared from 0.48 ml of isocaproic acid, 0.38 ml of oxalyl chloride and 5 ml of methylene chloride) in methylene chloride at 5-10° C., and stirred at ambient temperature for 2 hours. The whole was acidified to pH 2.0 with 2 mol/L HCl and extracted with CHCl3. The combined organic extracts were washed with water and brine, dried on MgSO4 and concentrated under reduced pressure. The residue was purified by chromatography, [eluent; chloroform:methanol=9:1] to obtain 1.10 g of (3S)-8-(3-methylbutylidene)-4-(4-methylpentanoyl)-1-thia-4-azaspiro[4.5]-decane-3-carboxylic acid as a colorless crystalline product.

Provenance & Evidence