59734-19-9Relevant academic research and scientific papers
The dutch resolution variant of the classical resolution of racemates by formation of diastereomeric salts: Family behaviour in nucleation inhibition
Dalmolen, Jan,Tiemersma-Wegman, Theodora D.,Nieuwenhuijzen, Jose W.,Van Der Sluis, Marcel,Van Echten, Erik,Vries, Ton R.,Kaptein, Bernard,Broxterman, Quirinius B.,Kellogg, Richard M.
, p. 5619 - 5624 (2007/10/03)
The resolution of racemates through their diastereomeric salts can be positively affected by the addition of small amounts of suitable nucleation inhibitors. This discovery is a logical extension of "Dutch Resolution", in which equimolar amounts of resolving agents that are members of the same family (i.e., structurally related) are used. We conducted a systematic search for nucleation inhibitors of the resolving agent 1-phenylethylamine. A wide range of amines that bear possible family resemblances to 1-phenylethylamine was investigated. It was found that (R)-1-phenylbutylamine is a good inhibitor of (R)-1-phenylethylamine. Results of turbidity measurements showed that, for the model case of mandelic acid resolution, the chief effect of this inhibitor was to widen the metastable zone for the more soluble diastereomer. This observation is in accordance with previous experience. Further scouting for possible family members revealed a wide variation in the effectiveness of inhibitors, dependent on their structure. By far the most effective inhibitors are bifunctional 1-phenylethylamine and/or 1-phenylbutylamine analogues. The effect of racemic inhibitors was found to approach that of enantiomerically pure inhibitors of the same absolute configuration of the 1-phenylethylamine used for resolution. The most effective inhibitors were tested for the resolution of a structural variety of racemates, and were shown to be broadly applicable.
Nitrogen-15 Nuclear Magnetic Rasonance Spectroscopy. Natural Abundance Nitrogen-15 Spectra of the cis and trans Isomers of Secondary Alkylformamides
Nakanishi, Hiroshi,Roberts, John D.
, p. 7 - 12 (2007/10/02)
The 15N NMR chemical shifts were measured of a number of N-substituted formamides and acetamides at the natural abundance level.The ratios of the cis and trans isomers for several N-alkylformamides were also determined.Substituent effects on the 15N chemical shifts of formamides are compared with those of some other nitrogen-containing compounds.There is a consistent pattern of behavior of the one bond spin-spin coupling constants 1J(15NH)> wherein the trans isomers of N-alkylformamides are larger than those of the cis isomers.
