The reaction of an aromatic heterocycle with a proton is called a protonation. One of articles about this theory is 《Intermediate products in the Arbuzov rearrangement》. Authors are Arbuzov, B. A.; Fuzhenkova, A. V.; Vinogradova, V. S.; Tolkacheva, T. G..The article about the compound:2,3-Dibromopropionic acidcas:600-05-5,SMILESS:O=C(O)C(Br)CBr).Recommanded Product: 2,3-Dibromopropionic acid. Through the article, more information about this compound (cas:600-05-5) is conveyed.
The literature on the subject is reviewed with 16 references. In a study of intermediates formed in the Arbuzov rearrangement the composition-property isotherms were determined for mixtures of (RO)3P and RX. Such diagrams for d. at 40°, 50°, and 70° with (EtO)3P-EtI mixture and for n at 50° and 70° for the same mixture are slightly convex toward the composition axis; viscosity of this system determined at 40°, 50°, 60°, and 70° gives values indicative of irrational systems with formation of a chem. dissociable compound which yields a decided viscosity maximum; at 40° this is located at 30 mole-% (EtO)3P, at 50° it is at 50 mole-%, at 60° it is at 35 mole-%, and at 70° (very sharp) it is at 25 mole-% (EtO)3P; this appears to indicate an increasing degree of dissociation with elevation of temperature The d. and viscosity isotherms for (EtO)3P-EtBr system taken at 75° are shown; the d plot shows a slight convexity toward the composition axis, while the viscosity plot shows a decided maximum near 50 mole-% composition; a very large maximum is found for the conductivity of this system in the same range of composition at 75°. Plots of d and n at 20° of the (EtO)3P-BrCH2CHBrOEt system show slight convexities toward the composition axis, while the viscosity plot is S shaped crossing the 45° diagonal at about 60 mole-% ester. Ultraviolet spectra are shown for (EtO)3P prepared either with the use of Et3N, Me2NPh, or EtONa; only the latter are free of absorption maximum typical of amine contaminations (cf. Halmann, C.A. 48, 10432b). Individual spectra of (EtO)3P and EtBr are shown along with those of 1:1 mixtures at temperatures to 100°; the latter show a purely additive effect at room temperature, but at 40-60° there is an increase of absorption at 2800-3100 A., becoming very pronounced at 80°, and declining once again at 100°; heating causes a shift of the maximum toward longer wavelengths, with results up to 190° being shown. The results indicate a formation of intermediate complex and eventual approach of the spectrum to that of a binary mixture of EtBr-EtP(O)(OEt)2; the fall of absorption at 100° and an increase at 120-70° are not explained. Similar curves with the phosphite prepared with Et3N are shown; these show the same pattern but the total absorption level is higher and the decline at 100° is smaller. Curves taken with the phosphite made with Et2NPh are masked by the residual amine absorption. Determinations of dipole moments are preliminarily reported. While the moment of MeI is 1.62 D and that of (PhO)3P is 1.59, their adduct in C6H6 shows a moment of 6.39 D; similarly, EtBr (1.79 D) and (EtO)3P (1.96 D) give an adduct intermediate whose moment rises with elevation of temperature (curves shown) and is either near 3.5 D or 2.3 D, depending on which mol. weight is used for the calculation (adduct or average values, resp.); the results indicate a formation of a complex beginning at 40-50°. The results also indicate by the high dipole moment after heating to 100-80°, that there may exist an equilibrium between RX and RP(O)(OR)2 at these conditions, forming an adduct of quasiphosphonium type; thus the dipole moment of a 1:1 mixture of EtBr and EtP(O)(OEt)2 is 2.38 D at 20°, 2.69 at 40°, and 2.75 at 60°. It is pointed out that deHauss (C.A. 47, 966a) reports data which are duplicates of those reported earlier by Milobendzki and Borowski (C.A. 33, 61562) without a reference to their paper.
This compound(2,3-Dibromopropionic acid)Recommanded Product: 2,3-Dibromopropionic acid was discussed at the molecular level, the effects of temperature and reaction time on the properties of the compound were discussed, and the optimum reaction conditions were selected.
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