Absolute configuration of 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol formed metabolically from 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone
Stephen S. Hecht,
Thomas E. Spratt and
Neil Trushin
The structures of the enantiomers of 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL) reported in this paper are reversed. In Figure 2, the correct order of elution should be [S-(Z)]NNAL-(S)-MTPA, [S-(E)]NNAL-(S)-MTPA, [R-(Z)]NNAL-(S)-MTPA, and [R-(E)]NNAL-(S)-MTPA. These were prepared by reaction of racemic NNAL with (R)-(-)MTPA chloride. The correct assignments in Figure 3B and Table I are: entry 1, (S)-NNAL-(S)-MTPA; entry 2, (R)-NNAL-(S)-MTPA; entry 3, (R)-NNAL(R)-MTPA; entry 4, (S)-NNAL-(R)-MTPA. The origin of the mistake is the following: the acid chlorides used in the reactions to prepare the MTPA esters were (R)-(-)-MTPA chloride and (S)-(+)-MTPA chloride, not (S)-(-)-MTPA chloride and (R)-(+)-MTPA chloride as stated in the paper. Because of a quirk of nomenclature, (R)-(-)-MTPA chloride corresponds to (S)-()-MTPA as well as (S)-MTPA esters while (S)-(+)-MTPA chloride corresponds to (R)-(+)-MTPA and (R)-MTPA esters. The absolute configuration of 4-hydroxy-4-(3-pyridyl)butanoic acid (hydroxy acid) enantiomers were also assigned based on our original NNAL assignment and therefore are also reversed (1,2). We are aware of three other papers in which the NNAL assignments are reversed (35). The authors apologize for the confusion which may have been caused by this error.
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