Microbiological transformations. Part 12. The stereochemistry of some derivatives of 2,6-dimethyl-1,2,3,4-tetrahydroquinolin-4-ol. Single crystal X-ray analyses of cis- and trans-1-benzoyl-4-benzoyloxy-2,6-dimethyl-1,2,3,4-tetrahydroquinoline

Abstract

Configurational and conformational assignments have been made on cis- and trans-2,6-dimethyl-1, 2,3,4-tetrahydroquinolin-4-ol 1 and 2 and the N-benzoyl and N,O-dibenzoyl derivatives 3-6 from NMR spectroscopic measurements and single crystal X-ray crystallographic analyses of the dibenzoyl derivatives 5 and 6. On the basis of this work, previously isolated products of the microbial transformations of certain N-substituted 2-methylated 1,2,3,4-tetrahydroquinolines with the fungi Aspergillus niger and Cunninghamella elegans were characterised. Subsequent incubation of 1benzoyl-2-methyl-1,2,3,4-tetrahydroquinoline 7 with A. niger and C. elegans was determined to yield, predominantly, the cis-1-benzoyl-2-methyl-1,2,3,4-tetrahydroquinolin-4-ol 8.