Vitamin K

Abstract

A brief history of the vitamin is presented from its early discovery to structural and, finally, stereochemical determination. An overview of synthetic approaches to vitamin K 1 is discussed. Work by researchers in the late 1930s largely forms the basis of the modern‐day industrial synthesis. Since this early work, industrial research has been directed toward process improvements in the basic methodology. Of particular note is the search for improved condensation catalysts, refinements in the oxidation of the naphthohydroquinone to the naphthoquinone, and more environmentally attractive routes to vitamin K 3 . In the case of vitamin K 3 there has been significant work on replacements to the historical chromium reagents. A number of patents on biotechnological approaches to the K vitamins have appeared. A synopsis of this work as well as a review of the biosynthesis is discussed. A brief review of the physiological role of vitamin K is presented. In addition to its well‐understood role in blood coagulation, its specific importance in bone mineralization as well as its general metabolic function are active areas of research.

Possibilities and Limitations of ICP-Spectrometric Determination of the Total Content of Tin, Its Inorganic and Organic Speciations in Waters with Different Salinity Levels—Part 1: Determination of the Total Tin Content

“…In the ICP analysis of waters containing tin (IV) chloride and OTC, one can expect a significant underestimation of AS Sn [ 16 ]. To a certain extent, this fact can be explained by the high thermal stability of the OTC [ 45 , 46 , 47 ]. For example, tributyltin chloride boils without decomposition above 170 °C [ 45 ], trimethyl tin chloride boils at 154 °C [ 46 ] and tetrabutyl tin chloride boils at 145 °C [ 47 ].…”

“…To a certain extent, this fact can be explained by the high thermal stability of the OTC [ 45 , 46 , 47 ]. For example, tributyltin chloride boils without decomposition above 170 °C [ 45 ], trimethyl tin chloride boils at 154 °C [ 46 ] and tetrabutyl tin chloride boils at 145 °C [ 47 ]. The thermal stability of tin (IV) chloride (boils at 114.15 °C) [ 48 ] does not affect the determination of inorganic tin in the ICP analysis of natural waters with low salinity [ 16 ].…”