Anilinopiperidines

A mixture of 4-carbamoyl-4-N-anilinopiperidine and formamide is heated for 12 hours at 170°C. After cooling, the reaction mixture is divided between 100 parts water and 900 parts chloroform. The organic layer is separated, dried over MgSO, filtered and the filtrate is evaporated. The semisolid residue is stirred in ethyl acetate. The undissolved part is filtered off, washed with ethyl acetate, and dried, yielding 1-oxo-4-phenyl-2,4,8-triazaspiro-(4.5)decane. 

In addition, A -tetrazoUne-5-ones are interesting molecules for medicine in the field of anesthesia and obesity. Fentanyl (165), which is a synthetic opioid from the family of anilinopiperidines [126], is a very potent analgesic, though its action is difficult to control. Based on the structure of fentanyl... 

A stirred soln. of 1 M butyllithium in tetrahydrofuran at —78° treated with 4-methyl-thiazole via syringe under argon, 10 min later a soln. of l-benzyl-4-cyano-4-anilino-piperidine added rapidly via cannula, warmed to 0° over 0.5 h, and quenched with water - l-benzyl-4-(4-methylthiazol-2-yl)-4-anilinopiperidine. Y 87%. cf. Synth. Meth. 7, 858. F.e. incl. 2-furyl, 2-thienyl, and 2-pyridyl derivs. s. L.A. Kudzma et al.. Tetrahedron Letters 29, 6827-30 (1988) review of synthesis and properties of a-aminonitriles s. Y.M. Shafran et al., Russ. Chem. Rev. 58, 148-62 (1989). 

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