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The Regioselective 3-Alkylation Of Piperidine, Richard Dunn Todd
The Regioselective 3-Alkylation Of Piperidine, Richard Dunn Todd
Chemistry & Biochemistry Theses & Dissertations
The compounds: 3-allylpiperidine, 3-ethylpiperidine and 3-n-butylpiperidine have been synthesized by regioselectively alkylating the three position of piperidine. Piperidine was converted to N-chloropiperidine and then dehydrohalogenated to produce Δ1-piperideine. The enamide anion was generated by adding solutions of Δ1-piperideine to ethylmagnesium bromide or lithium diisopropylamide. Addition of alkylhalides produced 3-alkyl- Δ1-piperideine which could be reduced or alkyllithiated to give 3-alkylpiperidines or 2,3-dialkylpiperidines respectively.
The yields of products were low and the reaction generated a continuum of mono- and di-alkylpiperidines and there was evidence that several dimeric piperideines were formed. The low yields were discussed in …
Synthesis Of Dihydroisoquinolines And Tetrahydroisoquinolines, John J. Schlager
Synthesis Of Dihydroisoquinolines And Tetrahydroisoquinolines, John J. Schlager
Chemistry & Biochemistry Theses & Dissertations
Dihydroisoquinolines and tetrahydroisoquinolines are compounds which possess a variety of pharmacological activities. New easier methods of synthetic manipulations of these structures is of constant interest in the pharmaceutical industry.
This paper describes a new three step method of preparing 1-alkyl- and 1-aryl-tetrahydroisoquinolines from a tetrahydroisoquinoline. The synthesis involves the N-chlorination of tetrahydroisoquinoline followed by dehydrohalogenation with potassium superoxide. The reaction products are the dihydroisoquinolines. Overall yields range from 85-96%. The unsubstituted, 1-methyl-, and 1-phenyl-J,4-dihydroisoquinolines have been formed. Organometallation of the unsubstituted dihydroisoquinoline provides the 1-substituted tetrahydroisoquinoline. The 1-benzyl-, 1-n-butyl-, 1-ethyl-, 1-methyl-, and 1-phenyl-1,2,J,4-tetrahydroisoquinolines were prepared. The use of Grignard and …