Aluminium spectral properties

Selenous acid produces the corresponding selenadiazole (191 X = Se). The condensed thiadiazole (191 X = S) is resistant to oxidation, but is reconverted into (190) (90%) by reduction with lithium aluminium hydride. The spectral properties (n.m.r., u.v.) and half-wave potentials of the compounds (191 X = S or Se) point to coplanarity of the phenyl substituent with the bicyclic heteronucleus. ... 

The keto ether (187) on treatment with diethyl carbonate in presence of sodium hydride in 1,2-dimethoxyethane afforded the keto ether (188), which was made to react with methyl-lithium in ether, to obtain the tertiary alcohol (189). This on being refluxed with methanolic hydrochloric acid yielded the phenol (190). It was methylated to yield(191) and heated with zinc, zinc iodide and acetic acid to produce pisiferol (192). Its methyl derivative (193) on oxidation with Jones reagent at room temperature, followed by esterification, furnished the keto ester (194). Reduction of (194) with metal hydride produced an alcohol whose tosyl derivative on heating with sodium iodide and zinc dust furnished the ester (195). Its identity was confirmed by comparing its spectral data and melting point with an authentic specimen [77]. The transformation of the ester (195) to pisiferic acid (196) was achieved by treatment with aluminium bromide and ethanethiol. The identity of the resulting pisiferic acid (196) was confirmed by comparison of its spectroscopic properties (IR and NMR) with an authentic specimen [77]. 

Only at the end of the article were there a few words about Mendeleev s note. Boisbaudran admitted that he had read it with great interest since classification of simple substances interested him for a long time. He had never known about Mendeleev s prediction of eka-aluminium properties but it did not matter Boisbaudran believed that his discovery of gallium was facilitated by his own laws of spectral lines of elements with similar chemical properties. In his opinion, spectral analysis played a decisive role. And not a word that Mendeleev in his prediction of eka-aluminium also underlined the prominent role of spectral analysis in the discovery of the new element. According to Boisbaudran, Mendeleev s predictions had nothing to do with the discovery of gallium. 

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