The discovery of vitamins as essential factors in the diet was a scientific breakthrough that changed the world. Diseases such as scurvy, rickets, beriberi, and pellagra were recognized to be curable with an adequate diet. These diseases had been prevalent for thousands of years and had a dramatic impact on societies as well as on economic development. This Review highlights the key achievements in the development of industrial processes for the manufacture of eight of the 13 vitamins.
Three 2,2'-bipyridine (2,2'-bpy) complexes of Pt(IV) have been synthesized, characterized by X-ray crystallography, and their solution behavior in D(2)O studied by (1)H NMR spectroscopic analysis: mer-[PtCl(3)(2,2'-bpy)(MeNH(2))]ClH(2)O (4), trans-[PtCl(2)(2,2'-bpy)(MeNH(2))(2)]Cl(2) (5), and trans-[Pt (2,2'-bpy)(MeNH(2))(2)(OH)(2)]Cl(2) (6; MeNH(2)=methylamine). Complexes 4 and 5 undergo hydrolysis of the Cl(-) ions, both in the dark and daylight, as evident from a drop in the pH value. Two solvolysis products were detected in the case of 4, which is indicative of species with equatorial and axial OH(-) groups. The hydrolysis reaction of 5 implies that an axial Cl(-) group is replaced by an OH(-) moiety; in contrast, 6 remains virtually unaffected. Ordinary daylight, in particular irradiation with a 50-W halogen lamp, initially causes ligand-isomerization processes, which are followed by the reduction of 4 and 5 to Pt(II) species. This reduction of 4 and 5 is accompanied by the formation of hypochlorous acid, as demonstrated qualitatively in the decoloration test of indigo, and loss of MeNH(2), which is particularly pronounced in the case of 5. The formation of Pt(II) compounds is established on the basis of the J coupling constants of (195)Pt with selected (1)H NMR resonances. The results obtained herein are possibly also relevant to the chemistry of Cl-containing Pt(IV) antitumor agents and their reactions with DNA.
Die Entdeckung der Vitamine als lebenswichtige Verbindungen in der Nahrung vor 100 Jahren stellte einen wissenschaftlichen Durchbruch dar, der die Welt veränderte. Die Erkenntnis, dass sich früher weit verbreitete Krankheiten wie Skorbut, Pellagra, Rachitis und Beriberi durch eine ausgewogene Ernährung vermeiden oder heilen lassen, hatte einschneidende Auswirkungen auf Gesellschaft und wirtschaftliche Entwicklung. Dieser Aufsatz fasst Schlüsselerfolge in Entwicklung und industrieller Herstellung von acht der insgesamt dreizehn Vitamine zusammen.
Pyrimidine
synthesis starting from acrylonitrile has been known
since the 1960s. The new Lewis acid-catalyzed condensation reaction
allows the synthesis of 4-aminopyrimidines starting from the easily
accessible chemical acrylonitrile without the need for carcinogenic
chemicals and costly derivatization in up to 90% yield. The method
is versatile and applicable for industrial-scale synthesis of biologically
relevant substances such as vitamin B1 and trimethoprim.
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