Author Topic: Novel high-yielding C=C reduction of nitrostyrenes  (Read 15177 times)

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« Reply #20 on: June 12, 2003, 10:53:00 PM »
Will this procedure (Ketone formation by nef reaction) work with MD2NP -> MDP2P?

I am VERY interested in that.

Thanks for all your hard work~


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« Reply #21 on: June 13, 2003, 01:17:00 PM »
I don't know if MDP2NP would be converted cleanly to MDP2P with this method, but I suspect that a decent yield can be achieved. Sulfuric acid is very gentle to the MD-bridge as opposed to the other mineral acids. My guess is that the reaction between the sodium salt of the nitroalkane and the acid should proceed in a way that the liberated nitrogen oxides is allowed to get in contact with the ketone or nitroalkane is little as possible. This should prevent oxidative destruction.


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Nef Reaction Review
« Reply #22 on: June 23, 2003, 05:54:00 AM »
If you are looking for other Nef reaction variations, here ia a review article of the Nef Reaction:

Chem. Rev. 55, 137 (1955)



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Reverse Addition of LAH to Nitroölefins - A
« Reply #23 on: July 01, 2003, 10:13:00 AM »
The original text can be found on Rh's site:

J Am Chem Soc 74(7) (1952) 1837-1842

( Thank you both Rh and Lego for offering me the requested text. As you both replied to my request within a period of time I was absent, I was unable to erase the request in time. Sorry...

[Contribution no 247 from the department of Organic Chemistry and Enzymology, Fordham University.]

Reverse Addition of Lithium Aluminium Hydride to Nitroölefins

by RT Gilsdorf 1 and FF Nord

The reverse addition of lithium aluminium hydride (LAH) to 1-phenyl-2-nitropropene-1 was studied in detail in order to correlate this method with those previously recorded in the literature for the reduction of nitroölefins. A variety of products was isolated by varying the reaction temperature and the ratio of reactants. Among them was 1-phenyl-2-nitropropane, arising from the selective reduction of the double bond. By employing acidic hydrolysis of the intermediary organometallic complex, phenylacetone was obtained via a modified Nef reaction. Several other alpha-aryl ketones were similarly prepared. A study on the reverse addition of LAH to omega-nitrostyrene, led to the development of a novel method of converting benzaldehyde to its next higher homolog.

A. Reduction of 1-Phenyl-2-Nitropropene-1


It has been shown 2,3 that when compounds of the type ArCH=CRX, where X is a polar group such as CHO, COOH or NO2, are treated with LAH via normal addition, the double bond, as well as the functional group, is reduced. However experiments 4 on the reverse addition of the above reagent to cinnamaldehyde demonstrated that the carbonyl function could be selectively reduced by such a method. In view of the above findings and of the fact that nitroölefins prepared from aromatic aldehydes conform to the type ArCH=CRX, where X is NO2, the reverse addition of LAH to nitroölefins was studied, as a continuation of our earlier investigation, 3 to correlate this method with those previously reported 5 for the reduction of nitroölefins. In these latter cases a wide variety of products has been obtained but at no time has any uncondensed 6 beta-aryl nitroalkane been isolated.
The nitroölefins chosen for study was 1-phenyl-2-nitropropene-1.


Reduction of 1-phenyl-2-nitropropene-1 to beta-phenylisopropylamine and N-(beta-phenylisopropyl)-hydroxylamine. - In a three-necked two-liter flask equipped with a mechanical stirrer, dropping funnel and a condenser through which was suspended a low temperature thermometer (openings protected with calcium chloride tubes), a solution of 12.2 g (0.075 mole) of 1-phenyl-2-nitropropene-1 in 300 mL of absolute ether was cooled to below -30°C with an acetone-dry ice bath. During rapid stirring, a solution of 4.25 g (0.112 mole, the calculated amount for the reduction of the nitro group) of LAH in 100 mL of absolute ether, was added at such a rate that the temperature of the reaction mixture was maintained between -30°C and -40°C. Exothermic reaction progressed during the addition and the color of the nitroölefin was discharged. The temperature in the reaction flask was then allowed to fall below -40°C, the freezing bath was removed and the temperature allowed to rise to 15°C. Hydrolysis was carried out with 400 mL of 20% aqueous sodium potassium tartrate. The addition of the first few drops of this solution caused slight reaction indicating that the hydride had not been completely utilized. The qaueous layer was extracted with two additional 50-mL portions of ether and the combined ethereal extracts, after drying over Drierite, yielded, on rectification, 4.4 g (44%) of beta-phenylisopropylamine, bp 72-74°C (4.0 mm) and 2.6 g (23%) of N-(beta-phenylisopropyl)-hydroxylamine, bp 116-118°C (4.0 mm). The latter substance was solidified. Recrystallization from light petroleum ether afforded a white crystalline solid, mp 63-64°C. Anal.: Calcd for C9H13NO: C, 71.42; H, 8.66. Found: C, 71.69; H, 8.42.
The beta-phenylisopropylamine isolated was characterized as its hydrochloride and phenylthioreide: the hygroscopic hydrochloride, prepared by bubbling anhydrous hydrogen chloride through a solution of the amine in absolute ether, after recrystallization from an absolute alcohol-ether combination, had a mp of 147-148°C. In the literature 7, the mp is listed as 145-147°C. Anal.: Calcd for C9H14ClN: N, 8.15. Found: N, 8.30. The phenylthioreide, prepared in the usual way 8, had a mp of 131.5-132.5°C after recrystallization from alcohol. Anal.: Calcd for C14H18N2S: C, 71.07; H, 6.71. Found: C, 71.30; H, 6.38.
The previously unreported N-(beta-phenylisopropyl)-hydroxylamine readily reduced Tollens reagent at room temperature. It had the same melting point as, and did not depress the melting point of, N-(beta-phenylisopropyl)-hydroxylamine synthesized according to an earlier method 9: A mixture of 1.5 g (0.01 mole) of phenylacetoxime dissolved in 25 mL of 70% alcohol containing 0.365 g of HCl and 0.1 g of platinum black was shaken under hydrogen until 0.01 mole was taken up. The catalyst was removed by filtration. The volume of the filtrate was increased to 75 mL with water and extracted with ether. The aqueous portion was then neutralized with aqueous sodium bicarbonate and the precipitate was collected. On recrystallization from light petroleum ether, there was obtained 0.64 g (42%) of N-(beta-phenylisopropyl)-hydroxylamine, mp 63-64°C, which was not depressed when mixed with the sample obtained from the reverse addition of LAH to 1-phenyl-2-nitropropene-1.

N-(beta-phenylisopropyl)-hydroxylamine oxalate. - When 0.18 g (0.02 mole) of oxalic acid dissolved in 10 mL of absolute ether, was added, with stirring, to a solution of 0.6 g (0.04 mole) of N-(beta-phenylisopropyl)-hydroxylamine in 10 mL of absolute ether, there was obtained a white precipitate of the neutral oxalate which, on recrystallization from an absolute methanol-ether mixture, melted at 175-176°C. Anal.: Calcd for C20H28N2O6: C, 61.21; H, 7.19. Found: C, 61.30; H, 6.99.

N-(beta-phenylisopropyl)-p-nitrophenylnitrone. - The procedure employed here was essentially reported previously. 10 There were mixed together 0.3 g (0.02 mole) N-(beta-phenylisopropyl)-hydroxylamine dissolved in 6 mL of absolute alcohol and 0.3 g (0.02 mole) p-nitrobenzaldehyde in 10 mL of absolute alcohol. After standing 24 hours, the alcohol was removed under reduced pressure and the residue was recrystallized from absolute ether (freezer). There was thus obtained a light yellow crystalline product, mp 119-120°C. Anal.: Calcd for C16H16N2O3: C, 67.59; H, 5.67. Found: C, 67.45; H, 5.67.

beta-Phenylisopropylamine. - A solution of 6.0 g (0.04 mole) of N-(beta-phenylisopropyl)-hydroxylamine in 80 mL of absolute ether was treated with 1.9 g (0.05 mole) of LAH dissolved in 150 mL of absolute ether in the usual manner and refluxed for an additional hour. After cooling, a sample of the reaction mixture gave a positive Gilman-Schultz color test 20 indicating an excess of the hydride. Hydrolysis was carried out with 400 mL of 20% aqueous sodium potassium tartrate and after separation of the layers, the aqueous portion was extracted with two additional 75-mL volumes of ether. Rectification afforded 2.0 g (37%) of beta-phenylisopropylamine, bp 72-74°C (4.0 mm), identified by is phenylthioreide.

N-(beta-phenylisopropyl)-hydroxylamine and phenylacetoxime. - When 2.13 g (0.056 mole, half the amount necessary for the reduction of the nitro group) dissolved in 100 mL of absolute ether, was added to 12.2 g (0.075 mole) of 1-phenyl-2-nitropropene-1 in 300 mL of absolute ether at -30° to -40°C, as before, and after hydrolysis with 20% aqueous sodium potassium tartrate, there were obtained 1.1 g (8%) of beta-phenylisopropylamine, bp 72-74°C (4.0 mm), and 5.6 g of a fraction 11, bp 116-118°C (4.0 mm), which failed to reach rigid solidity after 2 days in a vacuum desiccator over sulfuric acid. A portion of this material was treated with warm petroleum ether (bp 30-60°C). After decantation petroleum ether, on cooling, yielded crystalline N-(beta-phenylisopropyl)-hydroxylamine.
Another aliquot of the higher boiling fraction was dissolved in ether and shaken with an excess of cold 1 N HCl to remove the hydroxylamine derivative. The ether layer was then washed well with water and dried over Drierite. Removal of the ether on the steam-bath afforded an oil which on chilling and scraping, solidified. Recrystallization from petroleum ether (bp 60-75°C) yielded phenylacetoxime of mp 68.5-70°C. In the literature 12 the mp is recorded as 68-70°C. Anal.: Calcd. for C9H11NO: C, 72.45; H, 7.43. Found: C, 72.40; H, 7.24.
A third aliquot of the higher boiling fraction was weighed (2.0 g) and dissolved in 100 mL of 6 N HCl. Steam was passed through the solution until phenylacetone (identified as its semicarbazone) ceased to be distilled. The clear acidic hydrolytic solution was made basic with 4 N sodium hydroxide, afforiding 1.36 g of N-(beta-isopropyl)-hydroxylamine. Assuming that the ketone was quantitatively hydrolyzed and that there was no loss of the hydroxylamine in handling, this experiment allows the estimation of the ketoxime content of the mixture as being 32%. This corresponds to over-all yields of 8% beta-phenylisopropylamine, 16% phenylacetoxime and 34% N-(beta-phenylisopropyl)-hydroxylamine.

Action of 2,4-dinitrophenylhydrazine sulfate on phenylacetoxime. - When phenylacetoxime was treated with 2,4-dinitrophenylhydrazine sulfate in the usual manner 13, precipitation occurred immediately. Recrystallization from an ethyl acetate-alcohol mixture afforded orange crystals of mp 152.5-153.5°C which was not depressed when mixed with an authentic sample of the 2,4-dinitrophenylhydrazone of phenylacetone. This mp was originally reported as 155.5-156.5°C 14. Anal.: Calcd for C15H14N4O4: N, 17.83. Found: N, 17.70.

Phenylacetone (via phenylacetoxime). - A solution of 2.13 g (0.056 mole, half the amount necessary for the reduction of the nitro group) of LAH in 100 mL of absolute ether, was added to 12.2 g (0.075 mole) of 1-phenyl-2-nitropropene-1 in 300 mL of absolute ether, at -30° to -40°C , as above. After the temperature of the reaction mixture had been allowed to rise to 15°C, 300 mL of 6 N HCl was introduced to hydrolyze the intermediate organometallic complex. The layers were seperated and the ethereal layer was successively washed with two 100-mL volumes of 6 N HCl. The combined aqueous acidic portions were steam distilled. The distillate was extracted with the original ether layer and two additional 50-mL portions of ether. Rectification afforded 2.9 g (29%) of phenylacetone, bp 73-74°C (4.0 mm)
The 2,4-dinitrophenylhydrazone was prepared and recrystallized as previously indicated. Its mp was 152.5-153.5°C.
The semicarbazone was prepared according to the usual procedure 15. Recrystallization from 75% alcohol afforded a white crystalline product of mp 186-187°C. This mp was previously reported 16 as 187°C. Anal.: Calcd. for C10H13N3O: C, 62.80; H, 6.85. Found: C, 63.25; H, 6.61.

1-Phenyl-2-nitropropane. - A. LAH (0.855 g, 0.0225 mole, a 20% excess of the amount required for the reduction of the double bond) in 100 mL of absolute ether, was added to 12.2 g (0.075 mole) of 1-phenyl-2-nitropropene-1 in 300 mL of absolute ether at -40° to -50°C as described above. The organometallic complex was hydrolyzed with 20% aqueous sodium potassium tartrate. On rectification, there was obtained 4.7 g (38%) of 1-phenyl-2-nitropropane, bp 103-104°C (4.0 mm). Anal.: Calcd for C9H11O2: C, 65.43; H, 6.71. Found: C, 65.99; H, 6.69.
B. When the above experiment was repeated using as the hydrolytic agent the calculated amount of 1 N HCl which was introduced dropwise over the course of three quarters of an hour, 1.5 g (15%) of phenylacetone and 6.9 g (56%) of 1-phenyl-2-nitropropane were obtained.
1-Phenyl-2-nitropropane gave a definite blue-green coloration characteristic of the pseudo-nitroles produced by secondary nitro compounds when treated according to the conditions of the nitrous acid test. 17 The coloration was chloroform extractable. A similar test performed omitting the sodium nitrite, gave only a very faint green color.

beta-Phenylisopropylamine. - By the normal addition, 1.65 g (0.01 mole) of 1-phenyl-2-nitropropane in 50 mL of absolute ether, was treated with 0.68 g (0.018 mole, a 20% excess) of LAH in 70 mL of absolute ether. Hydrolysis was brought about by means of 150 mL of 20% aqueous sodium potassium tartrate. Upon distillation of the ethereal layer, there was obtained a small amount of oil which gave a phenylthioureide of mp 131.5-132.5°C which was not depressed when mixed with an analyzed sample of the phenylthioureide of beta-phenylisopropylamine.

Nef reaction 18 on 1-phenyl-2-nitropropane. - One-half of a gram of 1-phenyl-2-nitropropane was dissolved in 10 mL of aqueous solution containing 0.5 g of sodium hydroxide. This solution was added dropwise to a solution of 2.5 mL of concentrated sulfuric acid and 16 mL of water during rapid stirring and cooling with an ice-bath. An oil separated with the characteristic odor of phenylacetone. It was extracted with ether and after the removal of the ether, was treated with semicarbazide hydrochloride and sodium acetate in the usual manner for the preparation of a semicarbazone 15. In this way, there was obtained a white crystalline product, which, after recrystallization from 80% alcohol, had the same mp as, and did not depress the mp of, an authentic sample of the semicarbazone of phenylacetone (186-187°C).

Absorption data. The IR curves (Figs 2, 3, 4 - (refer to original text)) were obtained on a Perkin-Elmer 21-Double beam spectrophotometer using Nujol mulls of the samples.


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second part...
« Reply #24 on: July 01, 2003, 10:37:00 AM »

The experiments carried out on 1-phenyl-2-nitropropene-1 and its reductive derivatives are outlined in Figure 1 (refer to original text). These reactions demonstrated that the reduction was stepwise and capable of regulation so as to afford the amine, hydroxylamine derivative, oxime or nitroparaffin in various mixtures. While the formation of Complex I was undoubtedly the favored reaction at -40 to -50°C since the nitroparaffin, 1-phenyl-2-nitropropane, was obtained in 56% yields, and while some of Complex II must have been formed at -30 to -40°C to account for the phenylacetoxime isolated, neiter reaction has been proven as being mutually exclusive of each other at the temperatures involved.
The preparation of its hydrochloride and phenylisothioureide served to characterize the beta-phenylisopropylamine formed. The identity of the N-(beta-phenylisopropyl)-hydroxylamine was proven by its ready reduction of Tollens reagent, the preparation of its oxalate, the nitrone formation and by the fact that it did not depress the melting point of an authentic sample prepared according to the method of Vavon and Crajcinovic. 9 The phenylacetoxime was characterized by virtue of its melting point, hydrolysis to phenylacetone and conversion to the 2,4-dinitrophenylhydrazone. The blue-green coloration, manifested by pseudonitroles which are formed by secondary nitro compounds under the conditions of the V Meyer nitrous acid test 17, its reduction to beta-phenylisopropylamine with LAH and conversion to phenylacetone when treated according to the conditions of the Nef reaction, established the structure of 1-phenyl-2-nitropropane.
The reduction of N-(beta-phenylisopropyl)-hydroxylamine to beta-phenylisopropylamine with LAH is novel since we have been able to find no report in the literature on the reduction of a hydroxylamine derivative with this reagent.
It is noteworthy that the phenylacetoxime and N-(beta-phenylisopropyl)-hydroxylamine distilled together in the fraction obtained at 116-118°C (4.0 mm) The fact that the distillate failed to crystallize readily, led to the assumption that it might be a mixture. This contention was verified by the chemical separation of the components and supported by the IR absorption data. Curve H was obtained for N-(beta-phenylisopropyl)-hydroxylamine. It is noticed that there is a strong absorption band at 1108 cm-1 which is absent in curve O. Curve O, that of phenylacetoxime, demonstrateds absorption at 1666 cm-1 assignable to the C=N bond of the oxime group. Curve D, that of the reaction distillate, shows absorption at both the above frequencies and, in general, has all the peaks present in curves H and O.
The major portion of the phenylacetone formed when one half the amount of LAH was added at -30 to -40°C, probably arose from the acidic hydrolysis of the oxime which, itself, was isolated by applying hydrolysis with 20% aqueous sodium potassium tartrate.
The conversion of the nitroölefin to the corresponding nitroparaffin, 1-phenyl-2-nitropropane, is novel since no similar reduction, i.e., the selective reduction of the double bond, has been reported in the aryl series without condensation 6.
The fact that either 1-phenyl-2-nitropropane or phenylacetone can be isolated from the same reaction mixture depending on the type of hydrolysis, indicates that the mechanism of the ketone formation when the lower concentration of hydride was used, is a modified Nef reaction. The transitory blue color which is characteristic of the Nef reaction, and which was observed during the hydrolysis, supports this contention.
In view of the findings by Hochstein and Brown 4 on the reduction of cinnamyl alcohol to hydrocinnamyl alcohol, it is possible that the reduction of 1-phenyl-2-nitropropene-1 to 1-phenyl-2-nitropropane involves only the double bond 19 and is effected by 0.25 mole of LAH per mole of nitroölefin.


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Reverse Addition of LAH to Nitroölefins - B
« Reply #25 on: July 01, 2003, 03:01:00 PM »
B. Synthesis of other alpha-aryl ketones


Preparation of other alpha-aryl ketones and N-(beta-aralkyl)-hydroxylamines. - By treating the corresponding nitroolefins with a 20% excess of the amount of LAH necessary for the reduction of the double bond via reverse addition at -40 to -50°C, followed by hydrolysis by means of the rapid introduction of 400 mL of 6 N HCl, and steam distillation of the aqueous phase, the ketones, listed in Table I (cf original text), were prepared. The corresponding N-(beta-aralkyl)-hydroxylamines were isolated in low yields by making the aqueous acidic solution through which the steam had been passed, alkaline and extracting with ether.

1-o-Chlorophenyl-2-nitropropene-1. - A. Modified Knoevenagel-Walter Synthesis. There were refluxed together for 8 hours, 28.1 g (0.2 mole) of o-chlorobenzaldehyde, 15.0 g (0.2 mole) of nitroethane, 1.74 g (0.02 mole) of n-amylamine and 30 mL of absolute alcohol. On cooling, the mixture was stored in the refrigerator until the precipitation was complete. The mixture was filtered and the precipitate washed with a few mL of absolute alcohol. There were thus obtained 20.0 g of 1-o-chlorophenyl-2-nitropropene-1. An additional amount of 2.0 g was obtained by concentration of the filtrate and washings, bringing the total yield to 56%. B. Knoevenagel-Walter synthesis. 21 - When the same quantities of the above reagents were mixed and allowed to stand at room temperature for 2 weeks, and the product was isolated in the same manner, there was obtained a total yield of 24.1 g (61%) of 1-o-chlorophenyl-2-nitropropene-1. Recrystallization from absolute ethanol produced bright yellow crystals, mp 40°C. Anal.: Calcd for C9H8ClNO: C, 55.00; H, 4.08. Found: C, 54.98; H, 3.88.

2-Thienylacetoxime. - When 2-thienylacetone was treated in the usual manner 22 for the preparation of an oxime there was obtained, on recrystallization from petroleum ether (bp 60-75°C), a white crystalline product, mp 91-92°C, which was not depressed when mixed with a sample prepared according to the method of Bouveault and Wahl 2e by the action of aluminium amalgam on 1-(2-thienyl)-2-nitropropene-1.


The preparation of the ketones listed in Table I demonstrated the general applicability of this method of synthesizng carbonyl compounds from beta-arylnitroölefins. In general, the yields were good, the lowest (43%) being obtained from the relatively unstable 1-(2-thienyl)-2-nitropropene-1. The ketones are assumed to arise via the same mechanism as did phenylacetone in the previous experiment, i.e. by a modified Nef reaction after the selective reduction of the double bond of the nitroalkene.
The substituted hydroxylamines listed in Table I all readily reduced Tollens reagent at room temperature.
The experiments on the synthesis of the previously unreported 1-o-chlorophenyl-2-nitropropene-1 showed a slightly higher yield for the Knoevenagel-Walter synthesis (61% vs 56%) as compared to the much shorter reaction time of the modified Knoevenagel-Walter synthesis (8 hours vs 14 days).
The authenticity of the oxime prepared from 2-thienylacetone was proven by means of the mixed melting point determination with the sample obtained by the reduction of 1-(2-thienyl)-2-nitropropene-1 with aluminum amalgam.

C. Reduction of omega-nitrostyrene


Reduction of omega-nitrostyrene to beta-phenylethylamine, N-(beta-phenylethyl)-hydroxylamine and phenylacetaldoxime. - When 2.13 g (0.056 mole, half the amount necessary for the reduction of the nitro group) of LAH dissolved in 100 mL of absolute ether, was added to 11.2 g (0.075 mole) of omega-nitrostyrene at -30 to -40°C as before and after hydrolysis with 20% aqueous sodium potassium tartrate, a mixture of products was obtained. Upon distillation, there was isolated 0.5 g (6%) of beta-phenylethylamine, bp 72-77°C (6.0 mm). The residue 11b in the distilling flask was dissolved in ether and extracted with an excess of 1 N HCl. After removal of the ether by distillation there was obtained 1.6 g (16%) of phenylacetaldoxime which melted at 97-98°C after recrystallization from petroleum ether (bp 60-75°C). The recorded 23 mp is 97-99°C. Anal.: Calcd for C8H9NO: C, 71.09; H, 6.71. Found: C, 71.03; H, 6.45. Neutralization of the acidic washings with dilute aqueous sodium carbonate afforded 3.4 g (33%) of N-(beta-phenylethyl)-hydroxylamine. After recrystallization from light petroleum ether, it melted at 83-84°C. Anal.: Calcd for C8H11NO: C, 70.04; H, 6.71. Found: C, 70.12; H, 7.93.

Phenylthioureide of beta-phenylethylamine. - This white crystalline substance was synthesized according to the previously utilized procedure 4. Its mp was 110-110.5°C. The mp was previously reported 24 as 111°C. Anal.: Calcd for C15H16N2S: C, 70.27; H, 6.29. Found: C, 70.38; H, 6.10.

beta-Phenylethylamine hydrochloride. - This compound was prepared by the previously described procedure. It was recrystallized from an absolute alcohol-ether combination. It mp was 215-217°C. Literature 25 records the mp as 217°C.

Action of 2,4-dinitrophenylhydrazine sulfate on phenylacetaldoxime. - When 0.5 g of phenylacetaldoxime was treated according to the prveiously utilized procedure for the preparation of a 2,4-dinitrophenylhydrazone, there was obtained an orange crystalline solid, mp 121-121.5°C, which did not depress the mp of an authentic sample of the 2,4-dinitrophenylhydrazone of phenylacetaldehyde.

N-(beta-phenylethyl)-p-nitrophenylnitrone. - When 2.7 g (0.02 mole) of N-(beta-phenylethyl)-hydroxylamine dissolved in 6 mL of absolute alcohol, and 0.3 g (0.02 mole) of p-nitrobenzaldehyde dissolved in 10 mL of absolute alcohol had been mixed together, the solution started to deposit yellow crystals after 2 hours standing at room temperature. After 24 hours the precipitate was filtered and recrystallized from absolute alcohol. In this way there was obtained a yellow crystalline solid, mp 157-158°C. Anal.: Calcd for C15H14N2O3: C, 66.65; H, 5.22. Found: C, 66.75; H, 5.29.

N-(beta-phenylethyl)-hydroxylamine oxalate. - The neutral oxalate was prepared as previously described and recrystallized from a methanol-ether combination. Its mp was 165.5-167°C with decomposition. Anal.: Calcd for C18H24N2O6: C, 59.30; H, 6.59. Found: C, 59.85; H, 6.49.

Phenylacetaldehyde. - When 0.855 g (0.0225 mole, a 20% excess for the reduction of the double bond) of LAH was treated with 11.2 g (0.075 mole) of omega-nitrostyrene via reverse addition at -40 to -50°C and hydrolysis was brought about by 400 mL of 6 N HCl introduced rapidly, there was obtained after steam distillation of the acidic hydrolytic mixture and rectification, 0 to 0.46 g (0-5%) of phenylacetaldehyde, bp 61-65°C (5.0 mm).
When hydrolysis of the intermediate organometallic complex was effected with the calculated amount of 1 N HCl, added slowly, the ether layer afforded a crude yellow oil which, when treated according to the nitrous acid test, gave an orange-red coloration comparable in shade and intensity to that given by 1-nitrobutane when similarly treated.
The crude oil was then triturated with a solution of 4.0 g of sodium hydroxide in 75 mL of water to yield a dispersion which, when added to an ice cold solution of 12.5 mL of sulfuric acid in 80 mL of water during rapid stirring (Nef reaction), allowed the separation of 0.92 g (10%) of phenylacetaldehyde, bp 63-64°C (5.0 mm).
The methone derivative of phenylacetaldehyde was prepared by the usual method. 26 Its mp was 164-165°C, the same as reported previously. 27
The 2,4-dinitrophenylhydrazone of phenylacetaldehyde was prepared as before. Its mp was 121-121.5°C which was not depressed when mixed with an authentic sample.


In general, the experiments on the reduction of omega-nitrostyrene via the reverse addition of LAH indicated that it behaved similarly to 1-phenyl-2-nitropropene-1. In most cases, the same derivatives were prepared to characterize the various products.
However, a dissimilarity showed itself in the synthesis of the carbonyl derivative insofar as the yield of phenylacetaldehyde was very low. It is believed that here the mechanism of the reduction is still comparable while the ease of hydrolysis differs. The facts that a positive nitrous acid test was obtained for a primary nitro group and that the yield of phenylacetaldehyde marks the first reliable synthesis of the next higher homolog of benzaldehyde via omega-nitrostyrene, since the reported reduction of omega-nitrostyrene to the aldoxime followed by hydrolysis to the aldehyde, 28 has been described as being incapable of repetition. 29.


1. condensed from a part of the dissertation submitted to the Graduate Faculty of Fordham University in partial fulfillment for the degree of Doctor of Philosophy.
2. (a) RF Nystrom e.a. JACS 69, 1197 (1947) (b) 69, 2548 (1947) (c) 70, 3738 (1948).
3. RT Gilsdorf e.a. JOC 15, 807 (1950).
4. FA Hochstein e.a. JACS 70, 3484 (1948).
5. (a) G Alles. ibid. 54, 271 (1942) (b) O Schales. Ber 68, 1579 (1935) (c) J Kindler e.a. Ann 511, 209 (1934) (d) B Reichert e.a. Arch Pharm 273, 265 (1935) (e) L Beauvault e.a. CR 134, 1145 (1902) (f) A Sonn e.a. Ber 50, 1513 (1917) (g) H Cerf de Mauney. Bull Soc Chim [5] 7, 133 (1940) (h) EP Kohler e.a. JACS 43, 1281 (1923).
6. The reduction of omega-nitrostyrene to 2,3-diphenyl-1,4-dinitrobutane has been reported 5f.
7. DH Dey. JCS 18 (1930).
8. RL Shriner, RC Fuson. Identification of Organic Compounds", 3rd ed, J Wiley and Sons, Inc, NY 1948, p 206.
9. G Vavon e.a. Bull Soc Chim [4] 43, 231 (1928).
10. GW Watt e.a. JOC 8, 540 (1943).
11. (a) This fraction was incorrectly described as benzyl methyl ketimine in our preliminary communication, JACS 72, 4327 (1950). The hydrated trimer of the imine mentioned, actually was the hydroxylamine derivative; (b) similarly, a mixture of phenylacetaldoxime and N-(beta-phenylethyl)-hydroxylamine was mistaken for phenylacetaldimine and the compound erroneously described as the hydrated trimer of the aldimine, was actually the hydroxylamine derivative.
12. PW Neber e.a. Ann 449, 109 (1926).
13. RL Shriner, RC Fuson. Identification of Organic Compounds", 3rd ed, J Wiley and Sons, Inc, NY 1948, p 171.
14. WD McPhee e.a. JACS 66, 1132 (1944).
15. RL Shriner, RC Fuson. Identification of Organic Compounds", 3rd ed, J Wiley and Sons, Inc, NY 1948, p 170.
16. PA Levene e.a. J Biol Chem 90, 81 (1931).
17. V Meyer. Ann 175, 120 (1875).
18. HB Hass e.a. Chem Rev 32, 399 (1943).
19. It is also quite possible that the reduction may occur via a 1,4-addition especially in view of the polarity of the nitro group and of the fact that the reduction takes place at -40 to -50°C. It was reported 4 that the reduction of the double bond of cinnamyl alcohol proceeds slowly at room temperature after the rapid interaction of the polar alcoholic group with the hydride.
20. HB Hass e.a. JOC 15, 8 (1950).
21. E Knoevenagel e.a. Ber 37, 4502 (1902).
22. RL Shriner, RC Fuson. Identification of Organic Compounds", 3rd ed, J Wiley and Sons, Inc, NY 1948, p 202.
23. W Dollfus. Ber 25, 1917 (1892).
24. J von Braun e.a. Ber 45, 2188 (1912).
25. K Kindler,

Patent DE362714

26. EC Horning e.a. JOC 11, 93 (1946).
27. KH Lin e.a. JCS 2005 (1938)
28. L Bouveault e.a. Bull Soc Chim [3] 29, 518 (1903).
29. HB Hass e.a. Chem Rev 32, 399 (1943).


  • Guest
Good Work
« Reply #26 on: July 01, 2003, 11:49:00 PM »
impressive to having posted all that GC,

thank you for the hard time  ;) .


  • Guest
Cuisiner avec GC/MS: la Soupe Stupéfiante
« Reply #27 on: July 03, 2003, 01:56:00 PM »
I have tried Ba's method, but usually in a more or less adapted way. I never added all nitrostyrene (NS) at once, as he did. Barium uses a small molar excess of NaBH4 in his procedure. Maybe the small molar excess is sufficient to bring the reaction to a good end, but it is not for the way I do it.

Ingredients: 50 mmol NS, 1.1 molar eq NaBH4, 0.3 g Aliquat 336, 25 mL toluene.

Procedure: The NaBH4 is weighed and dissolved in aqueous NaOH (I have a stock solution for this purpose, containing 0.4 g NaOH in 0.500 mL dH2O). This solution is added to a 250 mL RB flask containing 0.3 g Aliquat 336 and 25 mL toluene. The mixture is stirred vehemently for 5 minutes, after which the NS is added in portions. The rate of addition is determined by the colour of the reaction mixture. When adding the NS, the reaction mixture turns yellow. An exothermic reaction sets is and the colour becomes more or less colourless. When the reaction colour is colourless again, a new spoontip of NS crystals is dropped in. This way, the reaction temperature is kept under control as well. However, I noticed that the reaction mixture colour remained yellow once roughly 70-80% of the NS was added. When adding new NS crystals, there was no sizzling of the reaction mixture. My conclusion was that the NaBH4 was depleted. When adding an extra 0.5 molar eq NaBH4, the reaction continued smoothly. When all NS was added, the reaction was continued for 45 minutes and residual NaBH4 was neutralized with GAA. Workup according Ba's method resulted in a 86% yield of 4-methoxy-phenyl-2-nitropropane, which was a pale yellow oil. Addition of all Ns consumed 1.5-2 hours.

Repeating the experiment with 50 mmol phenyl-2-nitropropene and 2.0 molar eq NaBH4 resulted in a smoothly running reaction and there was no need to add extra NaBH4 during the reaction. Phenyl-2-nitropropane was obtained in 90% yield as very pale yellow oil. Addition of all NS consumed about 1.5 hours.

Identity has been checked with MS, and both nitroalkanes displayed M+ which were 2 amu higher then the M+ in the spectra of their nitroalkene analogues.


  • Guest
Have you tried it with 2,5 DMNS ?
« Reply #28 on: July 03, 2003, 02:35:00 PM »
Nitropropenes are less prone to dimerization. I've tried it with 2,5 DMNS in microscale and the TLC was not really good. It's not enough to conclude anything, I could fuck something.


  • Guest
« Reply #29 on: July 03, 2003, 02:50:00 PM »
I could fuck something

You aren't expecting me to reply on that, do you?  ;D


  • Guest
No, of course.
« Reply #30 on: July 03, 2003, 05:23:00 PM »
What I want to know is if you have tried it with nitrostyrenes.


  • Guest
« Reply #31 on: July 04, 2003, 02:54:00 AM »
He tried it first with 50 mmol nitrostyrene (NS) and got a 86% yield of 4-methoxy-phenyl-2-nitropropane.
Then he repeated the reaction with phenyl-2-nitropropene and excess, better said, enough NaBH4 and got 90% yield of phenyl-2-nitropropane.

Who's making a typo here, GC_MS or Sunlight?  LT/  :)


  • Guest
No typo, just unclarity
« Reply #32 on: July 04, 2003, 03:36:00 AM »
Phenyl-2-nitropropene is a beta-methyl-substituted beta-nitrostyrene, so there is nothing wrong with calling nitropropenes nitrostyrenes (Shulgin does that all the time). However, Sunlight wants to know if it has been tried on plain nitrostyrenes (without that beta-methyl), as they are more prone to dimerization.


  • Guest
« Reply #33 on: July 04, 2003, 08:20:00 AM »
NS = nitrostyrenes; phenyl-2-nitropropene = alfa-methyl-NS  :P

Sunlight, no, not tested (yet).


  • Guest
« Reply #34 on: July 05, 2003, 01:35:00 AM »
This once more indicates that we should restrict ourselfs to IUPAC or/and CAS nomenclature.
And include those nrs in important procedures, for the precursors and endproducts.

There must be one Hive-guideline for nomenclature, and we should discuss elsewhere which nomenclature we must follow :

The HTML version of IUPAC "Blue Book" Nomenclature of Organic Chemistry, Pergamon
Press, Oxford, 1979 and A Guide to IUPAC Nomenclature of Organic Compounds.
Description: Recommendations 1979 and 1993. Nicely organized and searchable.

Basic Organic Nomenclature, An Introduction.
Dave Woodcock ©1996,2000  Okanagan University College. UP to DATE! IUPAC Chemical Nomenclature Searchable:

IUPAC International Union of Pure and Applied Chemistry :
USA     :



  : Search IUPAC.


UK      :

Systematized Nomenclature of Medicine, better known as SNOMED® :

Released in January 2002. SNOMED users include many leading organizations in the health care industry and health information technology field, from nationwide provider organizations and HMOs to pharmaceutical companies, Web portals and government agencies.

CAS, Chemical Abstracts Service HomePage :

  World's largest and most comprehensive chemical database with over 21 million document records.

The CAS Substance Databases:   
 * help you identify over 21 million organic and inorganic substances and 29 million sequences, each with a unique CAS Registry Number
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 = Regulated Chemicals Information:

, read, then go to:

  CHEMLIST contains national inventory information from Australia, Canada, Europe, Israel, Japan, Korea, Philippines, Switzerland, Taiwan, and the United States. These are NOT the CONTROLLED Substances lists!
 * verify that the substance is available from a supplier
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Where can I find CAS REGISTRY Numbers? Find CAS Registry Numbers in online databases  :

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You can use STN with confidence because the system and the more than 200 databases (

) it brings you are operated by some of the most respected scientific organizations in the world.

Opinions ? LT/


  • Guest
« Reply #35 on: July 08, 2003, 01:10:00 AM »
make own sticky thread for this, too important to bee hidden
inside an exciting thread like this.
(not implying that nomenclature is boring...)


  • Guest
« Reply #36 on: July 27, 2003, 07:10:00 PM »
Even though it gives good yields I've never been completely happy with Aliquat 336 as PTC in this reduction. Finally the need of this PTC is no more and I'm happily singing a little tune.  :)

Reduction of 2,5-dimethoxy-beta-nitrostyrene to 2-nitro-1-(2,5-dimethoxyphenyl)ethane

10,5 g (50 mmol) 2,5-dimethoxy-beta-nitrostyrene was added during 5 minutes to a solution of 2,4 g  (63 mmol, 1,25 mol eq.) sodium borohydride in 50 ml water and 25 ml IPA1. The temperature rose from 20 to 50°C while the orange color faded to a slightly yellow. 2N HCl was then carefully2 added until pH 4 was reached followed by enough solid NaCl to cause the IPA to form a separate layer containing the product. Two volumes of water was added to the isolated IPA layer which caused 2-nitro-1-(2,5-dimethoxyphenyl)ethane to separate as a clear yellow oil and was isolated by extraction with 2x15 ml toluene. The organic phase dried over MgSO4 and the solvent removed under vacuum leaving the product as a clear yellow oil. Yield 9,7 g (46 mmol, 92%) 2-nitro-1-(2,5-dimethoxyphenyl)ethane.

Low-pressure hydrogenation of 2-nitro-1-(2,5-dimethoxyphenyl)ethane to 2C-H

The 2-nitro-1-(2,5-dimethoxyphenyl)ethane isolated above was added to a suspension of 2g 5%Pd/C in 50 ml EtOH (which had been treated with hydrogen under 4 bar pressure at 55°C for 10 minutes) followed by 15 ml GAA and 20 ml water. The pressure was kept at 5 bar for three hours and the temperature at 55°C. The reactor was opened and the catalyst removed by filtration then the EtOH was distilled away under reduced pressure. The remaining solution was extracted with 2x30 ml toluene, saturated with NaCl then the pH was raised to 14 and the amine isolated by extraction with 2x30 ml toluene. The organic phase was dried over MgSO4 and the solvent removed by distillation under reduced pressure leaving 2C-H as a slightly yellow oil. The amine was dissolved in EtOAc and acidified to pH 4 with 5N HCl/IPA and the hydrochloride isolated by filtration and dried to constant weight. Yield 7,8 g (36 mmol, 78%) 2C-H*HCl as white crystals.

[1] The reaction is so quick that the addition of NaOH to stablize the borohydride solution is not necessary.
[2] 1,25 Mol eq. borohydride was used to reduce the nitrostyrene. I believe less borohydride can be used since so much was left after the reaction was over as evidenced during acidification. About 1,05-1,1 mol eq. is probably enough.


  • Guest
« Reply #37 on: July 27, 2003, 10:27:00 PM »
If you continue to improve the synthesis of 2C-H at the same rate as you have been doing the past year, I believe that before the spring of 2005 the 2C-H will practically synthesize itself already when storing the reagents close to each other in an unventilated room  ;)


  • Guest
Not only 2C-H
« Reply #38 on: July 28, 2003, 03:42:00 PM »
Not only 2C-H but even the fully active 2C-C since 2C-H.HCl is obtained and he menaged to get 2C-C from 2C-H.HCl according to another superb hall-of-fame BariumTM writeup...


  • Guest
Please help with rxn, mentioned above.
« Reply #39 on: October 03, 2003, 03:30:00 PM »
Hi, bees!
SWIT got problem with wet reduction of 2,5DMNS.

Last night he did rxn, which was recommended by Barium:

10,5 g (50 mmol) 2,5-dimethoxy-beta-nitrostyrene was added during 5 minutes to a solution of 2,4 g  (63 mmol, 1,25 mol eq.) sodium borohydride in 50 ml water and 25 ml IPA. The temperature rose from 20 to 50°C while the orange color faded to a slightly yellow...
The mixture turn deep yellow, not slightly. It was stirred about 20 minutes, and then 2N HCl was added till pH=4, after this step SWIT had 2 layer: water-layer and deep orange oil, which collected on the bottom of beaker... Trying to separate this oil gave him a tar  :(  
Please, help.
What did he do wrong? May bee one need to stir solution more long or what???