Lithium aluminium hydride analysis using

A new, stereospecific synthesis of (+)-isoretronecanol, by a transannular route, has been developed by Leonard et al. Dieckmann cyclisation of NN-bis-(y-ethoxycarbonylpropyl)benzylamine gave ethyl l-benzyl-5-oxo-l-azacyclo-octane-4-carboxylate (20), whose perchlorate was shown to possess a bicyclic structure. Hydrogenation of this perchlorate in ethanol, using palladised charcoal catalyst, afforded ethyl ( )-isoretronecanolate perchlorate (22) as sole product, presumably by stereospecific addition of hydrogen at the less hindered face of the intermediate debenzylated immonium ion (21). Reduction of the free base corresponding to (22), by means of lithium aluminium hydride, gave (+ )-isoretronecanol (23), the stereochemical purity of which was shown by g.l.c. analysis to be >98%. 

If the purity of the synthetic standards is questionable, the following is suggested use the (impure) ng/yl standards to obtain retention time and the detector linear range. Then, during the analysis, add the appropriate phenyltin chloride directly to a test tube and derivatize with lithium aluminium hydride, eliminating the usual extraction and concentration steps. Since the conversion occurs quantitatively, peak heights from these derivatization standards can be used to construct a standard curve. The procedure calls for... 

Phenolic (and amine) antioxidants in extracts of PVC have been titrated electrometrically with lithium aluminium hydride, using platinum or silver electrodes. Small amounts of water in the sample or analysis solvent have an influence on the results obtained by these procedures. 

Tri-O-acetyl-D-glucal has been used for the synthesis of a number of functionalized cir-decalins, via pyranone 79. Intramolecular Diels-Alder reaction of 79 gives the tricylic intermediate 80. Lithium aluminium hydride reduction affords a 1 1.7 mixture of alcohols which are separated and elaborated to 81 and 82 (Scheme 15). Ferrier rearrangement converts these to cir-decalins 83 the structures of which were proven by single crystal X-ray analysis. ... 

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