title: Preparation of racemic 2r-carboxy-trans, trans-3,4-dideutero-pyrrolidine (DL-trans, trans-3,4-dideutero-proline) and unambiguous assignment of protons in the 1H n.m.r. spectrum of proline.
abstract: Racemic trans-3,4-dideutero proline has been prepared by catalytic deuteration of 3-pyrroline-2-carboxylic acid. The stereospecificity of the reduction (i.e. trans to the carboxylic group) was ascertained after transformation of the dideutero compound into the diketopiperazide c/Pro, Aib/, for which unambiguous proton assignments in the 1H n.m.r. spectrum had been obtained previously. The identification of the configuration of the dideuteroproline allows for the affirmation of the correctness of proton assignments as previously proposed in literature.
mesh_terms: D055598:Chemical Phenomena; D002621:Chemistry; D003903:Deuterium; D007536:Isomerism; D008968:Molecular Conformation; D011392:Proline / Q000031:analogs & derivatives* / Q000138:chemical synthesis; D011522:Protons; D013057:Spectrum Analysis
chemical_list: D011522:Protons; C002195:3,4-dehydroproline; D011392:Proline; D003903:Deuterium