Deoxy carbon-13 nuclear magnetic resonance

As indicated in Section 11,4 (p. 64), direct treatment of alkyl halides with sodium cobalt tetracarbonyl, carbon monoxide, and methanol at elevated temperatures and pressures yields esters. Surprisingly, application of this reaction at 60° (using methanol instead of ether) to methyl tri-0-acetyl-2-deoxy-2-iodo-/3-D-glucopyranoside gave, almost exclusively, the elimination product (88) (in deacetylated form) and a compound presumed to be (on the basis of nuclear magnetic resonance evidence only) the branched-chain ester (87) in less than 0.5 % yield. It is thought that, in the presence of methanol, the sodium cobalt tetracarbonyl dissociates to yield sodium methoxide, and that this causes deacetylation of the substrate. 

Products of considerable potential interest for the synthesis of 2-amino-2-deoxyaldose derivatives have been obtained by the addition of nitrosyl chloride to acetylated glycals. Tri-O-acetyl-n-glucal and di-O-acetyl-n-arabinal react smoothly in carbon tetrachloride at 0° to give crystalline products which, on the basis of their chemical reactivities and their nuclear magnetic resonance spectra, have been assigned the structures of tri-0-acetyl-2-deoxy-2-nitroso-Q -D-glucopyranosyl chloride (32) and di-O-acetyl-2-deoxy-2-nitroso-j3-n-arabinopyranosyl chloride (33). It was not estab-... 

Nuclear magnetic resonance (NMR) spectroscopy is an invaluable instrumental technique for the structural determination of all flavonoids including 3-deoxy-anthocyanins. As well as providing information on the chemical environment of each proton or carbon nucleus in the molecule, the technique can be employed to determine linkages among nearby nuclei, often enabling a complete structure to be assembled. The reader is referred to Refs. 44 and 45 for details of the principles of NMR and general interpretation of NMR spectra. 

---