Hantzsch sentence example

hantzsch
  • Hantzsch (Ber., 1901, 34, p. 3337) has shown that in the action of alcohols on diazonium salts an increase in the molecular weight of the alcohol and an accumulation of negative groups in the aromatic nucleus lead to a diminution in the yield of the ether produced and to the production of a secondary reaction, resulting in the formation of a certain amount of an aromatic hydrocarbon.
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  • Hantzsch (Ber., 1889, 22, p. 1238) succeeded in ob R taining derivatives of o-diketo-R-hexene, which yield R-pentene and aliphatic compounds on decomposition.
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  • The quinonoid structure of many coloured compounds has been proved experimentally, as, for example, by Hewitt for the benzene-azo-phenols, and Hantzsch for triaminotriphenyl methane and acridine derivatives; but, at the same time, many substances cannot be so explained.
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  • The theories of colour have also been investigated by Hantzsch, who first considered the nitro-phenols.
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  • The proof of this was left for Hantzsch, who traced a connexion with the nitrolic acids of V.
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  • Hantzsch explains the transformation of the colourless acid into red salts, which on standing yield more stable, colourless salts, by the following scheme: N R.0N O H R CA O R'CC NO 2Na 2 O?
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  • (3) If a colourless compound gives a coloured one on solution or by salt-formation, the production of colour may be explained as a particular form of ionization (Baeyer), or by a molecular rearrangement (Hantzsch).
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  • Hantzsch and L.
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  • Hantzsch (Ber., 1891, 24, p. 13) has made use of the Beckmann reaction, whereby they are converted into acid-amides.
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  • Hantzsch (Ber., 33, p. 522).
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  • Hantzsch, Ber., 18 97, 3 0, p. 2356).
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  • Hantzsch (Ann., 1896, 2 9 2, pp. 34 0 et seq.) hyponitrous acid and nitramide are to be regarded as stereoisomers, being the anti-and synforms of the same compound.
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  • Hantzsch (Ber., 18 99, 3 2, pp. 577 et seq.) are probably derived from the isomeric iso-nitro compounds R: NO(OH), and thus the nitro derivatives are to be looked upon as pseudo-acids.
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  • Hantzsch, Ber., 1899, 32, p. 631).
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  • Hantzsch on Pseudo-acids, Ber., 18 99, 3 2, p. 575, 1902, 35, pp. 210, 226, 1001, 1906, 39, pp. 1 39, 1073 et seq.).
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  • Hantzsch and 0.
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  • Hantzsch, Ber., 1906, 39, p. 139): Ordinary temperature Cyamelide (CNOH) 3 Cyanic acid CNOH HO ions 1 High Cyanuric acid Decomposes with temperature
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  • Hantzsch (Ber., 18 99, 3 2, pp. 59 o, 3089) considers that the oxyazo compounds are to be classed as pseudoacids, possessing in the free condition the configuration of quinone hydrazones, their salts, however, being of the normal phenolic type.
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  • Hantzsch and A.
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  • Hantzsch has shown that aldehydes condense with aceto-acetic ester and ammonia to produce the homologues of pyridine, thus: R R [[Rooc Ch 2 Cho Ch 2 Coor Rooc C - Ch - C Coor]] + + 1 = Ii II +3H20.
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  • Hantzsch, Ber.,i 891,24, p. 13).
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  • Hantzsch, Ber., 1900, 33, p. 2 553).
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  • Hantzsch and J.
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  • Hantzsch, Ber., 1900, 33, p. 2551).
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  • Hantzsch and E.
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  • Hantzsch (Ber., 18 9 6, 2 9, p. 947 1898, 31, p. 1253) has shown that the chlorand bromdiazoniumthiocyanates, when dissolved in alcohol containing a trace of hydrochloric acid, become converted into the isomeric thiocyanbenzene diazonium chlorides and bromides.
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  • Hantzsch and W.
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  • Hantzsch, Ber., 1896, 29, p. 1067; 1898, 31, p. 636.
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  • Hantzsch).
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  • Hantzsch, Ber., 1895, 28, p. 1 734).
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  • Hantzsch and his pupils seems to invalidate this view (Ber., 1894, 27, pp. 1702 et seq.; see also A.
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  • Hantzsch, DieDiazoverbindungen).
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  • According to Hantzsch the isomeric diazo hydroxides are structurally identical, and the differences in behaviour are due to stereo-chemica l relations, the isomerism being comparable with that of the oximes.
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  • On such a hypothesis, the relatively unstable normal diazo hydroxides would be the syn-compounds, since here the nitrogen atoms would be more easily eliminated, whilst the stable iso-diazo derivatives would be the anti-compounds, thus: R N R N HO-N N OH Normal hydroxide Iso hydroxide (Syn-compound) (Anti-compound) In support of this theory, Hantzsch has succeeded in isolating a series of syn - and anti-diazo-cyanides and -sulphonates (Ber.,1895,28, p.666; 1900, 33, P. 2161; 1901, 34, p. 4166).
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  • The isolation of these compounds is a powerful argument in favour of the Hantzsch hypothesis which requires the existence of these three different types, whilst the Bamberger-Blomstrand view only accounts for the forma tion of two isomeric cyanides, namely, one of the normal diazonium type and one of the iso-diazocyanide type.
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  • Hantzsch, Ber., This assumption also shows the relationship of the diazonium hydroxides to other quaternary ammonium compounds, for most of the quaternary ammonium hydroxides (except such as have the nitrogen atom attached to four saturated hydrocarbon radicals) are unstable, and readily pass over into compounds in which the hydroxyl group is no longer attached to the amine nitrogen; thus the syn-diazo hydroxides are to be regarded as pseudo-diazonium derivatives.
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  • Hantzsch, Ber., 18 99, 32, p. 3109; 1900, 33, p. 278.) It is generally accepted that the iso-diazo hydroxides possess the oxime structure R N: N OH.
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  • Hantzsch explains the characteristic reactions of the diazonium compounds ky the assumption that an addition compound is first formed, which breaks down with the elimination of the hydride of the acid radical, and the formation of an unstable syn-diazo compound, which, in its turn, decomposes with evolution of nitrogen (Ber., 18 97, 30, p. 2 54 8; 1898, 31, p. 2053).
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  • Soc., 1907, 91, p. 1049) suggested a quinonoid formula for diazonium salts, which has been combated by Hantzsch (Ber., 1908, 41, pp. 353 2 et seq.).
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  • Hantzsch, Ann., 1898, 299, p. 99).
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  • Hantzsch, Ber., 1900, 33, p. 2 55 1).
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  • Hantzsch (Ann., 1882, 215, p. I; Ber., 1882, 15, p. 2914) which consists in the condensation of two molecules of aceto-acetic ester with one of an aldehyde and one of ammonia: RO 2 C CH 2 R' CHO CH 2 CO 2 R RO 2 C C CHR' C C02R CH 3 CO + NH 3 + CO CH 3 -' CH3 C-NH-C CH3 The resulting dihydro-compound is then oxidized with nitrous acid, the ester hydrolysed and the resulting acid heated with lime; carbon dioxide is eliminated and a trisubstituted pyridine of the type CH C(CH3) is obtained.
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  • Hantzsch (Ber., 1886, 19, p. 31) by condensing methyl iodide and potassium nicotinate at 150° C. the resulting iodide being then decomposed by moist silver oxide.
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  • Hantzsch, Ann., 1896, 2 9 2, p. 3 1 7); by the action of hydroxylamine sulphate on alkaline nitrites in the presence of lime or calcium carbonate, the mixture being rapidly heated to 60° C.; or by the hydrolysis of dimethyl nitroso-oxyurea, (CH 3) 2 N CO N(NO) OH (A.
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  • Hantzsch (Ber., 1886, 19, p. 31) by condensing methyl iodide and potassium nicotinate at 150° C. the resulting iodide being then decomposed by moist silver oxide.
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  • Hantzsch, Ber., 1887, 20, p. 2780; 1889, 22, p. 1238), this type of reaction being generally brought about by the action of chlorine on phenols in the presence of alkalis (see Chemistry: Organic).
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