Brucine salts

This substance (dA, I A) contains a free carboxyl group and is treated in warm acetone solution with an equimolecular quantity of the optically active base brucine (IB) upon cooling, the brucine salt (dA, IB) separates out first in a moderately pure condition, whilst the brucine salt (lA, IB) remains in solution ... 

The latter upon decomposition with dilute hydrochloric acid yields laevo sec.-octyl hydrogen phthalate the crystalline brucine salt, when similarly treated, affords the dextro sec.-octyl hydrogen phthalate. These are reerystallised and separately hydrolysed with sodium hydroxide solution to yield pure I- and d-sec.-octyl alcohols ... 

Introduce 197 g. of anhydrous brucine or 215 g. of the air-dried dihydrate (4) into a warm solution of 139 g. of dZ-acc.-octyl hj drogen phthalate in 300 ml. of acetone and warm the mixture vmder reflux on a water bath until the solution is clear. Upon cooling, the brucine salt (dA, IB) separates as a crystalline solid. Filter this off on a sintered glass funnel, press it well to remove mother liquor, and wash it in the funnel with 125 ml. of acetone. Set the combined filtrate and washings (W) aside. Cover the crystals with acetone and add, slowly and with stirriug, a slight excess (to Congo red) of dilute hydrochloric acid (1 1 by volume about 60 ml.) if the solution becomes turbid before the introduction of... 

The filtrates from the decomposition of the brucine salts with dilute hydrochloride acid should be carefully preserved. The brucine Is recovered by the addition of an excess of dilute ammonia solution (1 4) if the solution becomes turbid before all the ammonia solution is added, introduce a little alcohol until the solution becomes clear. After several hours in an open beaker, filter oft the brucine, wash it well with cold water and dry it in the air. 

The resolution of sec.-octyl alcohol was first described by Pickard and Kenyon. The method employed by these authors differed from the foregoing in the following respects. The brucine salt of sec.-octyl hydrogen phthalate was crystallized several times from acetone until it reached optical purity and was then decom-... 

Dehydrocorydaline eontains four methoxyl groups. On reduetion it furnishes two stereoisomerides of eorydaline, m.p. 135°, and m.p. 158-9° (163-4° vac.), Spath) the latter ( 2f.9oeorydaline) by erj stallisation of the d-eamphorsulphonate can be partially separated into d- and Z-forms, the d-form of which is not identical with natural corydaline.The second isomeridc, m.p. 135°, has not been resolved into optically active components, but from the sulphonic acid the Z-compoiient has been isolated by crystallisation of the brucine salt, and this is taken to indicate that the inactive corydaline, m.p. 135°, is dZ-corydaliiie. °... 

The active variety of the terpene d-sylvestrene has been prepared synthetically by preparing the methyl-cyclohexane-carboxylic acid described above, and recrystallising its brucine salt. The acid contains a small quantity of the A acid, although the A variety predominates. The A acid was resolved by the brucine crystallisations, and an acid of rotation -t- 90° obtained. The synthetic process was then proceeded with, and the resulting terpene was found to be d-sylvestrene, having a rotation of -1- 66°. 

Optically active (+)- and (—)-p-(/-propylmethylphenylstannyl) benzoic acids (56) and their methyl esters (57) were similarly prepared by Lequan four years later 38) (see Table 3). They are characterized by very low optical rotations. Furthermore, the diastereomeric brucine salts via which the acids were resolved, are characterized by almost identical NMR spectra that cannot be used to follow their separation so that no precise information is available about the optical purity of (56) and (57). 

Lewis201 postulated maltosone as the first product in the oxidation of maltose by Fehling solution, but no osone was detected when maltose was treated with Fenton s reagent.23 Oxidation of maltosone with bromine water gave 2-oxo-maltobionic acid, isolated as its brucine salt.191... 

The first successful attempt in asymmetric synthesis was made by Marckwald in 1904 who prepared an active (-) -valeric acid by heating the half brucine salt of ethyl methyl malonic acid at 170°C. 

Having accomplished the resolution, it was found, however, that only one brucine salt could be isolated and that it mutarotated rapidly in solution from an initial reading of [a]o+30 35 to a final activity of... 

The acid which was isolated from this salt racemized to zero from an initial activity of [aJc —The occurrence of an opposite direction in the rotation of the free acid as compared with the brucine salt from which-it was isolated is not an uncommon occurrence (51). The brucine salt which was obtained from the filtrate after the insoluble salt was removed gave rise to an inactive acid. This, undoubtedly, was due to mutarotation taking place while the volume of the solution was reduced. 

The synthesis was then continued with both, the racemic diester and the pure enantiomer (-)-30a which was prepared by hydrolysis of the racemic diester, resolution of the corresponding acid via the brucine salt and reesterification. 

It had been known from at least the time of Pasteur that the presence of sodium or potassium phosphate aided the progress of a yeast fermentation. Later intensive study showed that a complex group of enzymes (phosphatases and phosphorylases) was responsible for the phosphorylation, dephosphorylation and interconversion of D-glucose 6-phosphate, D-fructose 6-phosphate, D-fructose 1,6-diphosphate and similar substances in various types of cells and muscle tissue. Detailed reviews of the field are available. - A further advance was made in 1936, when Cori and Cori noted that in certain circumstances well-washed frog muscle immersed in a sodium phosphate buffer utilized the inorganic phosphate to produce a new hexose phosphate (the Cori ester). This compound was later shown to be a-D-glucopyranose-l-phosphate and yielded crystalline dipotassium and brucine salts. The Cori ester arose because... 

The first optically active example was 117 ([a]D + 71 ° in ethanol through its brucine salt) for which a racemization barrier of 113 kJ mol-1 was found 127). In order to establish the mode of racemization the optically active derivatives, 118 and 119 were prepared through their cinchonidine and brucine salts, respectively ([a]D —21 and —78°, respectively)128), From racemization experiments with the methylesters of 118 and 119 (with barriers of 130 and 105 kJ mop1, respectively) it could be concluded that a biradical rearrangement predominates in 118, whereas for 117 and 119 a simple ring inversion process is in accordance with the results 128). 

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