Drag synthesis alkylation

Diphenoxylate Diphenoxylate, ethyl ester of l-(3-cyano-3,3-diphenylpropyl)-4-phenylpiperidine-4-carboxylic acid (3.1.58), is also a drag of 4-phenylpiperidine series. In practice there are two ways of making it. The first way is by the alkylation of the ethyl ester of 4-phenylpiperidine-4-carboxylic acid (3.1.56) with 2,2-diphenyM-bromobutyronitrile, which in turn is synthesized from l-benzyl-4-phenyM-cyanopiperidine. The product undergoes ethanolysis in the presence of acid, followed by benzylation. The second way is a synthesis accomplished by alkylation of diphenylacetonitrile using ethyl ester of l-(2-chloroethyl) -phenylpiperidine-4-carboxylic acid (3.1.57), which is synthesized by... 

Sufentanyl Sufentanyl, iV-(4-(methoxymethyl)-l-[2-(2-thienyl)ethyl]-iV-phenylpropanamide (3.1.72), is a drag that is analogous to alfentanil, but that differs by the substituent on the nitrogen atom of the piperidine ring. Its synthesis contains many of the same elements as the synthesis of alfentanil, and it only differs in the last stage, where alkylation of 4-methoxymethyl-4-iV-propionilanihnopiperidine (3.1.68) is carried out with 2-hydroxy-ethylthiophofene methanesulfonate [44-46]. 

An interesting synthesis of highly enantioenriched acyclonucleosides has been described employing as key step the addition of 9//-purines to alkyl substituted enals catalyzed by 7 (Scheme 11.19 (c)). Acyclonucleosides, which are potential antiviral drags, were obtained in 82-89% yield and up to 99% ee. 

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