Date of Award

Winter 1984

Project Type

Dissertation

Program or Major

Chemistry

Degree Name

Doctor of Philosophy

Abstract

The literature methods for the determination of chemical purity and ratio of cis and trans diastereoisomers of 1,2-diaminocyclohexane (DACH) from commercial sources were evaluated. Carbon-13 nuclear magnetic resonance spectroscopy was found to be most convenient for routine analysis. Gas chromatographic analysis after the Eschweiler-Clarke N-methylation was found to give a faulty isomer ratio unless special precautions were taken to insure complete reaction, since the cis isomer was found to undergo unusually slow conversion to its tetramethyl derivative compared to the rate of conversion of the trans isomer.

Optically active cis-2,3-diphenyldecahydroquinoxaline and trans-2,3-diphenyldecahydroquinoxaline were prepared by stereoselective reductions of 2,3-diphenylhexahydroquinoxaline obtained by the condensation of benzil and (-)-(R,R)-DACH enantiomer. Optically active N,N'-dibenzyl-1,2-diaminocyclohexane (DBDACH) was prepared by the NaBH(,4) reduction of the diimine obtained by the condensation of benzaldehyde and (-)-(R,R)-DACH enantiomer.

Three diamines were added to suspensions of lithium aluminum hydride (LAH) in ether to produce chirally modified LAH reagents. Propiophenone was reduced to (R)-1-phenylethanol in 36% enantiomeric excess (e.e.) by the DBDACH-LAH reagent. The reduction of propiophenone by LAH reagents modified with the two chiral decahydroquinoxalines resulted in carbinol with (S)-configuration but with small asymmetric inductions (less than 5% e.e.).

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