Abstract Generated abstract
This paper reports the synthesis and characterization of unsaturated alpha-alkylallyl and alpha-alkylcrotonyl esters of arsenious acid, prepared by reacting arsenic trichloride with secondary unsaturated alcohols in the presence of pyridine. The authors describe the resulting compounds as colorless, moisture-sensitive liquids soluble in common organic solvents, give boiling points, densities, refractive indices, molar refractions, and arsenic analyses, and compare their boiling points with analogous phosphorous acid esters. Reactions with acetic and benzoic anhydrides are shown to form mixed anhydrides of substituted arsenious acids, which are also air-unstable and readily hydrolyzed. The study further notes that these arsenious esters polymerize only weakly under conditions where related phosphorous esters show greater polymerization tendency.
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CHEMISTRY
GIL'M KAMAI and R. K. ZARIPOV
ON α-ALKYL DERIVATIVES OF ALLYL AND CROTONYL ESTERS OF ARSENIOUS ACID
(Presented by Academician A. E. Arbuzov, 9 XI 1961)
In the last decade, the study of unsaturated organoelement compounds has been developing intensively. Unsaturated arsenic compounds and, in particular, esters of arsenic acids with unsaturated radicals have been little studied \((^{1})\). In our laboratory, work on the synthesis of the allyl ester of arsenious acid was begun as early as 1947 \((^{2})\); it was continued somewhat later.
In developing our investigations in this direction, we set ourselves the goal of studying the reactions of arsenic trichloride with secondary unsaturated alcohols in the presence of pyridine according to the schemes:
\[ 3 \cdot \begin{matrix} \mathrm{CH_2{=}CH}\\[-2pt] \backslash\\[-2pt] \mathrm{CHOH}\\[-2pt] /\\[-2pt] \mathrm{R} \end{matrix} + \mathrm{AsCl_3} + 3\mathrm{C_5H_5N} \rightarrow \left( \begin{matrix} \mathrm{CH_2{=}CH}\\[-2pt] \backslash\\[-2pt] \mathrm{CHO}\\[-2pt] /\\[-2pt] \mathrm{R} \end{matrix} \right)_3 \mathrm{As} + 3\mathrm{C_5H_5N \cdot HCl}, \tag{1} \]
\[ 3 \cdot \begin{matrix} \mathrm{CH_3{-}CH{=}CH}\\[-2pt] \backslash\\[-2pt] \mathrm{CHOH}\\[-2pt] /\\[-2pt] \mathrm{R} \end{matrix} + \mathrm{AsCl_3} + 3\mathrm{C_5H_5N} \rightarrow \left( \begin{matrix} \mathrm{CH_3{-}CH{=}CH}\\[-2pt] \backslash\\[-2pt] \mathrm{CHO}\\[-2pt] /\\[-2pt] \mathrm{R} \end{matrix} \right)_3 \mathrm{As} + 3\mathrm{C_5H_5N \cdot HCl}. \tag{2} \]
As a result of the experiments carried out, we synthesized the following unsaturated α-alkylallyl and α-alkylcrotonyl esters of arsenious acid, given in Table 1. The α-alkylallyl and α-alkylcrotonyl esters of arsenious acid that we isolated are colorless liquids with a characteristic odor. They are readily hydrolyzed by atmospheric moisture and dissolve in ether, benzene, heptane, and alcohol. They also readily enter into reaction with mercuric chloride, forming crystalline products.
The atomic refraction of arsenic for these unsaturated esters of arsenious acid remains more or less constant (on average 8.56), but lower than for the fully alkyl esters of arsenious acid.
Table 2 gives the boiling points of the α-alkylallyl esters of arsenious acid and, for comparison, the analogous esters of phosphorous acid synthesized earlier by one of us \((^{3})\).
As is known, the simplest arsenic compounds have higher boiling points than the corresponding phosphorus compounds. This is clearly seen from our comparison of the temperature data for these esters; the difference ranges from 10 to 12°. We studied the reaction of α-alkylallyl and α-alkylcrotonyl esters of arsenious acid with acetic anhydride. As a result of the experiments performed, it was shown that alkyl derivatives of allyl and crotonyl esters of arsenious acid react with acetic anhydride upon heating, forming mixed anhydrides of the corresponding secondary di-α-alkylallyl- or di-α-alkylcrotonylarsen-
Table 1
| No. | Formula | B.p., °C/mm | \(d^{20}_{4}\) | \(n^{20}_{D}\) | \(MR_D\) | \(AR_D\mathrm{As}^{3+}\) | As, % found | As, % calc. |
|---|---|---|---|---|---|---|---|---|
| α-Alkyl allyl esters of arsenious acid | ||||||||
| 1 | \(\left(\begin{array}{c}\mathrm{CH_2{=}CH}\\[-2pt]\diagdown\ \mathrm{CHO}\\[-2pt]\diagup\ \mathrm{CH_3}\end{array}\right)_3\mathrm{As}\) | 103–104/10 | 1.1199 | 1.4637 | 70.99 | 8.20 | 26.15 | 25.99 |
| 2 | \(\left(\begin{array}{c}\mathrm{CH_2{=}CH}\\[-2pt]\diagdown\ \mathrm{CHO}\\[-2pt]\diagup\ \mathrm{C_2H_5}\end{array}\right)_3\mathrm{As}\) | 134/10 | 1.0857 | 1.4639 | 83.96 | 8.23 | 22.57 | 22.69 |
| 3 | \(\left(\begin{array}{c}\mathrm{CH_2{=}CH}\\[-2pt]\diagdown\ \mathrm{CHO}\\[-2pt]\diagup\ \mathrm{C_3H_7}\end{array}\right)_3\mathrm{As}\) | 150–151/12 | 1.0446 | 1.4645 | 98.49 | 8.55 | 20.12 | 20.26 |
| 4 | \(\left(\begin{array}{c}\mathrm{CH_2{=}CH}\\[-2pt]\diagdown\ \mathrm{CHO}\\[-2pt]\diagup\ \mathrm{C_4H_9}\end{array}\right)_3\mathrm{As}\) | 145–146/2–3 | 1.0140 | 1.4642 | 112.81 | 8.61 | 18.08 | 18.28 |
| 5 | \(\left(\begin{array}{c}\mathrm{CH_2{=}CH}\\[-2pt]\diagdown\ \mathrm{CHO}\\[-2pt]\diagup\ \mathrm{C_5H_{11}}\end{array}\right)_3\mathrm{As}\) | 182–183/3–4 | 0.9941 | 1.4647 | 127.14 | 8.74 | 16.41 | 16.27 |
| 6 | \(\left(\begin{array}{c}\mathrm{CH_2{=}CH}\\[-2pt]\diagdown\ \mathrm{CHO}\\[-2pt]\diagup\ \mathrm{C_6H_5}\end{array}\right)_3\mathrm{As}\) | 218–220/3 | 1.1973 | 1.5781 | 123.63 | 8.63 | 15.79 | 15.66 |
| α-Alkyl crotonyl esters of arsenious acid | ||||||||
| 1 | \(\left(\begin{array}{c}\mathrm{CH_3{-}CH{=}CH}\\[-2pt]\diagdown\ \mathrm{CHO}\\[-2pt]\diagup\ \mathit{iso}\text{-}\mathrm{C_4H_9}\end{array}\right)_3\mathrm{As}\) | 149–150/1 | 0.9895 | 1.4662 | 127.59 | 9.22 | 16.30 | 16.41 |
| 2 | \(\left(\begin{array}{c}\mathrm{CH_3{-}CH{=}CH}\\[-2pt]\diagdown\ \mathrm{CHO}\\[-2pt]\diagup\ \mathit{n}\text{-}\mathrm{C_4H_9}\end{array}\right)_3\mathrm{As}\) | 163–165/3 | 0.9936 | 1.4698 | 127.48 | 9.11 | 16.36 | 16.41 |
| 3 | \(\left(\begin{array}{c}\mathrm{CH_3{-}CH{=}CH}\\[-2pt]\diagdown\ \mathrm{CHO}\\[-2pt]\diagup\ \mathrm{C_6H_{11}}\end{array}\right)_3\mathrm{As}\) | 186–187/2 | 0.9798 | 1.4611 | 140.37 | 9.35 | 14.88 | 15.03 |
Table 2
| No. | Ester formula | B.p., °C/mm | Difference, °C | No. | Ester formula | B.p., °C/mm | Difference, °C |
|---|---|---|---|---|---|---|---|
| 1 | \(\left(\begin{array}{c}\mathrm{CH_2{=}CH}\\[-2pt]\diagdown\ \mathrm{CHO}\\[-2pt]\diagup\ \mathrm{CH_3}\end{array}\right)_3\mathrm{P}\) | 92–93/9 | 11 | 4 | \(\left(\begin{array}{c}\mathrm{CH_2{=}CH}\\[-2pt]\diagdown\ \mathrm{CHO}\\[-2pt]\diagup\ \mathrm{C_2H_5}\end{array}\right)_3\mathrm{As}\) | 134/10 | 10 |
| 2 | \(\left(\begin{array}{c}\mathrm{CH_2{=}CH}\\[-2pt]\diagdown\ \mathrm{CHO}\\[-2pt]\diagup\ \mathrm{CH_3}\end{array}\right)_3\mathrm{As}\) | 103–104/10 | 11 | 5 | \(\left(\begin{array}{c}\mathrm{CH_2{=}CH}\\[-2pt]\diagdown\ \mathrm{CHO}\\[-2pt]\diagup\ \mathrm{C_3H_7}\end{array}\right)_3\mathrm{P}\) | 137–139/13 | 12 |
| 3 | \(\left(\begin{array}{c}\mathrm{CH_2{=}CH}\\[-2pt]\diagdown\ \mathrm{CHO}\\[-2pt]\diagup\ \mathrm{C_2H_5}\end{array}\right)_3\mathrm{P}\) | 123–124/10 | 10 | 6 | \(\left(\begin{array}{c}\mathrm{CH_2{=}CH}\\[-2pt]\diagdown\ \mathrm{CHO}\\[-2pt]\diagup\ \mathrm{C_3H_7}\end{array}\right)_3\mathrm{As}\) | 150–151/12 | 12 |
arsenious and acetic acids according to the scheme:
\[ \left( \begin{array}{c} \mathrm{CH_2{=}CH}\\[-2mm] \backslash\ \mathrm{CHO}\\[-2mm] /\\[-2mm] \mathrm{R} \end{array} \right)_3 \mathrm{As} + \begin{array}{c} \mathrm{CH_3{-}CO}\\[-1mm] \backslash\\[-1mm] \mathrm{O}\\[-1mm] /\\[-1mm] \mathrm{CH_3{-}CO} \end{array} \to \left( \begin{array}{c} \mathrm{CH_2{=}CH}\\[-2mm] \backslash\ \mathrm{CHO}\\[-2mm] /\\[-2mm] \mathrm{R} \end{array} \right)_2 \mathrm{AsO{-}C(=O){-}CH_3} + \mathrm{CH_3COOCH} \begin{array}{c} \mathrm{CH{=}CH_2}\\[-1mm] |\\[-1mm] \mathrm{R} \end{array} \]
Some data on these mixed anhydrides are given by us in Table 3.
Table 3
| No. | \(R\) | B.p., °C/mm | \(d_4^{20}\) | \(n_D^{20}\) | \(AR_D^{As^{2+}}\) | As, % found | As, % calc. |
|---|---|---|---|---|---|---|---|
| \multicolumn{7}{c}{\(\mathrm{CH_3{-}COOAs}\left(\begin{array}{c}\mathrm{OCH}\\[-1mm] | \\[-1mm] \mathrm{R}\end{array}\ \begin{array}{c}\mathrm{CH{=}CH_2}\end{array}\right)_2\)} | |||||||
| 1 | \(\mathrm{CH_3}\) | 106—107/10 | 1.2285 | 1.4611 | 10.48 | 26.92 | 27.12 |
| 2 | \(n\)-\(\mathrm{C_3H_7}\) | 141—142/14 | 1.0832 | 1.4608 | 10.75 | 22.49 | 22.55 |
| 3 | \(n\)-\(\mathrm{C_4H_9}\) | 131—132/2 | 1.0792 | 1.4602 | 10.76 | 20.61 | 20.79 |
| 4 | \(n\)-\(\mathrm{C_5H_9}\) | 147—148/2 | 1.0657 | 1.4632 | 10.77 | 19.32 | 19.25 |
| \multicolumn{7}{c}{\(\mathrm{CH_3{-}COOAs}\left(\begin{array}{c}\mathrm{OCH}\\[-1mm] | \\[-1mm] \mathrm{R}\end{array}\ \begin{array}{c}\mathrm{CH{=}CH{-}CH_3}\end{array}\right)_2\)} | |||||||
| 5 | iso-\(\mathrm{C_4H_9}\) | 141—143/11 | 1.0501 | 1.4636 | 11.25 | 19.07 | 19.25 |
| 6 | \(n\)-\(\mathrm{C_4H_9}\) | 132—133/2 | 1.0699 | 1.4178 | 10.90 | 19.12 | 19.25 |
The isolated mixed anhydrides are colorless liquids which are unstable in air and hydrolyze with formation of a white precipitate of arsenic trioxide and the corresponding secondary unsaturated alcohol. In connection with the latter reaction, it was of interest to study the reaction of benzoic anhydride with \(\alpha\)-alkylallyl or \(\alpha\)-alkylcrotonyl esters of arsenious acid.
As a result of the experiments carried out, we established that when 1 mole of benzoic anhydride is allowed to act on 1 mole of \(\alpha\)-amylallyl ester of arsenious acid at an elevated temperature of about \(190^\circ\), the mixed anhydride of di-\(\alpha\)-amylallylarsenious and benzoic acids is formed according to the scheme:
\[ \left( \begin{array}{c} \mathrm{CH_2{=}CH}\\[-2mm] \backslash\ \mathrm{CHO}\\[-2mm] /\\[-2mm] \mathrm{C_5H_{11}} \end{array} \right)_3 \mathrm{As} + \begin{array}{c} \mathrm{C_6H_5CO}\\[-1mm] \backslash\\[-1mm] \mathrm{O}\\[-1mm] /\\[-1mm] \mathrm{C_6H_5CO} \end{array} \to \mathrm{C_6H_5COOAs} \left( \begin{array}{c} \mathrm{OCH}\\[-1mm] /\ \mathrm{CH{=}CH_2}\\[-1mm] \backslash\ \mathrm{C_5H_{11}} \end{array} \right)_2 + \mathrm{C_6H_5COOCH} \begin{array}{c} \mathrm{CH{=}CH_2}\\[-1mm] |\\[-1mm] \mathrm{C_5H_{11}} \end{array} \]
B.p. of the mixed anhydride 193—194° at 2 mm, \(d_4^{20}\) 1.0910, \(n_D^{20}\) 1.4992. Under analogous conditions, on interaction of benzoic anhydride with the \(\alpha\)-butylcrotonyl ester of arsenious acid, a mixed anhydride was isolated,
\[ \mathrm{C_6H_5COOAs} \left( \begin{array}{c} \mathrm{OCH}\\[-1mm] /\ \mathrm{CH{=}CH{-}CH_3}\\[-1mm] \backslash\ \mathrm{C_4H_9} \end{array} \right) \]
with b.p. 184—186° at 2—3 mm, \(d_4^{20}\) 1.0889 and \(n_D^{20}\) 1.4988.
The isolated mixed anhydrides are unstable in air and are readily hydrolyzed.
It should be noted that the $\alpha$-alkylallyl and $\alpha$-alkylcrotonyl esters of arsenious acid synthesized by us, in contrast to their analogs—the corresponding esters of phosphorous acid—do not possess a high capacity for polymerization in the presence of benzoyl peroxide and potassium bifluoride. Thus, for example, $\alpha$-phenylallyl ester of arsenious acid, when heated (90–130°) with 5% benzoyl peroxide in a sealed tube, after 30 days had acquired the state of a transparent semisolid resin that became turbid with time.
Kazan Chemical-Technological Institute
named after S. M. Kirov
Received
4 XI 1961
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