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All 7 posts Subject: 3,4-Methylenedioxyphenylacetaldehyde, etc. Please login to post Down

Rhodium
(Chief Bee)
02-13-03 23:49
No 407531
User Picture       3,4-Methylenedioxyphenylacetaldehyde, etc.

Homopiperonal und seine Derivate
Berichte 41, 2751-53 (1908)

Zur Unterscheidung derjenigen Bestandteile der ätherischen Öle, welche zur Benzolreihe gehören und in der Seitenkette eine Allyl- bezw. Propenylgruppe aufweisen, besitzen wir verschiedene Mittel: wir können nach. Balbiano¹durch Behandlung mit Quecksilberacetat usw. zu verschiedenen Derivaten kommen, je nachdem die Allyl- oder Propenylgruppe vorliegt; hierbei wird jedoch das Molekül als solches zuweilen angegriffen, und es gelingt nicht immer, das Ausgangsmaterial leicht zu regenieren; nach Semmler² kann man durch Behandlung mit konzentrierter Ameisensäure Propenylderivate zerstören, während sich die Allylverbindungen beim Kochen mit konzentrierter Ameisensäure nur wenig verändern.

Oxydiert man hierher gehörige Propenylverbindungen, wie Anethol, Asaron, Isosafrol usw., mit Ozon, so erhält than die zugehörigen Aldehyde, also Anisaldehyd, Asaronaldehyd, Piperonal usw. Wir konnten nun feststellen, dass bei Oxydation der Bestandteile ätherischer Öle, die eine Allylgruppe aufweisen, wie Safrol, Eugenol usw., durch Ozon das Molekül ebenfalls an der doppelten Bindung angegriffen wird und die Oxydation unter bestimmten Vorsichtsmaßregeln nicht weiter geht. Hiernach lassen sich also die korrespondierenden Homoverbindungen, wie Homopiperonal, Homovanillin usw., gewinnen; nebenher entstehen natürlich die zugehörigen Säuren.

Homopiperonal

Je 7 g Safrol werden in der gleichen Menge Benzol gelöst und mit ~3g Wasser vermischt. Hierauf wird ein lebhafter Ozonstrom ~4 Stunden lang hindurchgeleitet; alsdann treibt man durch das Reaktionsprodukt Wasserdampf, wobei Benzol und unangegriffenes Safrol übergehen. Der durch Zersetzung des Ozonids zurückbleibende Aldehyd wird unter Aussalzen ausgeäthert und im Vakuum destilliert; die gleichzeitig entstandene Säure wird dein Äther durch Soda entzogen.

Eigenschaften des Homopiperonals: Sdp₁₀ = 143-144°C, d20 = 1.295, nD = 1.57117. Der Aldehyd erstarrt alsbald und schmilzt, aus Methylalkohol umkrystallisiert, bei 69°C (Piperonal hat Schmp. 37°C). Der Geruch des Aldehyds ist von jenem des Piperonals deutlich verschieden, aber jedenfalls angenehm. Das Semicarbazon, in der üblichen Weise dargestellt, schmilzt, aus Methylalkohol umkrystallisiert, bei 189°C. Der Schmelzpunkt des Piperonal-semicarbazons liegt bei 236-238°C. Das Oxim zeigt den Sdp₁₀ = 180-181°C und schmilzt, aus Wasser umkrystallisiert, bei 124-125°C.

Das Homopiperonylsäurenitril wurde durch Kochen dieses Oxims mit der dreifachen Menge Essigsäureanhydrid dargestellt und zeigt folgende Eigenschaften: Sdp₁₀ = 153-156°C, d20 = 1.231, nD = 1.53698.

Aus diesem Nitril wurde durch Verseifen (1 g Nitril in 35g 10% alkoholischer Kalilauge) übergeführt in die Homopiperonylsäure. Die Säure wurde aus Wasser umkrystallisiert und schmolz alsdann bei 127°C. Ein Teil des Nitrils wurde reduziert zum Amin : Sdp₁₀ =146-148°C, d20= 1.225, nD =1.5620. Die ätherische Lösung dieses Amins gab mit einer ätherischen Lösung von Pikrinsäure ein sofort ausfallendes Pikrat, das bei 160°C unter Zersetzung schmilzt. Der Methylester der Homopiperonylsäure wurde aus der letzteren in Methylalkohol durch Einleiten von Chlorwasserstoff gewonnen; diese homopiperonylsäure war gleichzeitig neben dem Homopiperonal bei der Oxydation des Safrols mit Ozon entstanden. Der Methylester zeigte folgende Eigenschaften: Sdp₁₀ = 153-155°C, d20 = 1.246, nD = 1.534, Dieser Ester wurde zum Homopiperonylalkohol, in absoluten Alkohol mit Natrium reduziert: Sdp₁₀ = 156°C, nD = 1.54780. Der Alkohol erinnert im Geruch. an Ylang-Ylangöl.

Das auf diese Weise dargestellte Homopiperonal ist frei von Piperonal, so dass die Oxydation des Safrols und analoger Allylverbindungen mit Ozon unter Lösung der doppelten Bindungen Ozonide liefert, welche sich beim Kochen mit Wasser in die zugehörigen Aldehyde spalten.

Jedoch scheint eine weitere Abspaltung von Kohlenstoff, also z. B. in dein vorliegenden Falle beim Safrol, unter Bildung von Piperonal bezw. Piperonylsäure nicht stattzuhaben. Die Ausbeute an Homopiperonal bezw. Homopiperonylsäure beträgt ca. 50% der Theorie.

[1] Azione delia soluzione aquosa di acetato mercurico, Rom 1905.
[2] Berichte 41, 2185 (1908).

Aurelius
(Hive Addict)
02-19-03 19:17
No 409823
      English version please?

somebody?

thallium
(Newbee)
02-19-03 19:32
No 409829
      I'll translate it if noone else is working on...

I'll translate it if noone else is working on it:)

Video meliora proboque; Deteriora sequor. -Ovid

Aurelius
(Hive Addict)
02-19-03 19:55
No 409834
      greatly appreciated!

Thanks!

thallium
(Newbee)
02-19-03 23:13
No 409890
      Homopiperonal and its derivatives Report 41,...
(Rated as: excellent)

Homopiperonal and its derivatives
Report 41, 2751-53 (1908)

We have several different ways to separate allyl- and propenylbenzenes, occurring in essential oils, from each other:

We can according to Babiano (1) react the oil with mercuric acetate to get derivatives corresponding to the allyl- or propenyl benzene; but the molecules are attacked in such a way that it is not always easy to recover them. According to Semmler (2) propenyl derivatives are destroyed by concentrated formic acid; while boiling allyl derivatives with concentrated formic acid only slightly changes them.

If you oxidize the propenyl benzenes (like anethole, asarone, iso-safrole etc.) with ozone; you get the corresponding aldehydes (anisaldehyde, asaronealdehyde, piperonal etc.) We can now conclude that oxidation of the allyl benzenes (found in essential oils; like safrole, eugenole etc.) with ozone also attacks the double bond; and that the ozone won't react further, under the below mentioned conditions. Thus you get the corresponding homocompounds: homopiperonal, homovanilline etc.; in addition to the produced acids.

Homopiperonal

7g safrole is dissolved in the same amount of benzene, and mixed with approx. 3g water. Ozone is bubbled lively thru for around 4 hours. Then steam is bubbled thru; which makes the benzene and unreacted safrole pass over to the receiver. The aldehyde (from the "destroyed" ozonide) is salted out of the liquid and separated from it. It is distilled in vacuum, and the acid from the reaction is separated by reacting it with Na2CO3.

Properties of homopiperonals: bp10 = 143-144°C, d20 = 1.295, nD = 1.57117. The aldehyde solidifies immediately, and melts (crystals from methanol) at 69°C (Piperonal mp. 37°C). The smell of the aldehydes is easily separated from that of the piperonals; but still pleasant. The semicarbazone, prepared in the usual manner, melts (crystals from methanol) at 189°C. The melting point of the piperonal-semicarbazones is around 236-238°C. The oxim has a bp10 = 180-181°C, and melts (crystals from water) at 124-125°C.

The homopiperonylacetonitrile is prepared by boiling one part of this oxim with three parts acetic anhydride. It has the following properties: bp10 = 153-156°C, d20 = 1.231, nD = 1.53698.

This nitrile is reacted with alkali (1 g nitrile in 35g 10% KOH/ethanol) to create homopiperonylic acid. Mp (crystals from water) = 127°C. Some nitrile is reduced to the amine: bp10 =146-148°C, d20= 1.225, nD =1.5620. A solution of this amine in ether gave with a solution of picric acid in ether crystals of the picrate which melts with dec. at 160°C.

The methylester of the homopiperonylic acid is prepared by dissolving the acid in methanol and bubbling HCl thru the solution. This homopiperonylic acid was also created during the oxidation of safrole with ozone. The methyl ester has the following properties: bp10 = 153-155°C, d20 = 1.246, nD = 1.534. This ester is reduced with Na in absolute alcohol to homopiperonylic alcohol: bp10 = 156°C, nD = 1.54780. This alcohol smells somewhat like Ylang-Ylang oil.

The in this way prepared homopiperonal is free from piperonal; so the oxidation of safrole and allyl-analogues with ozone in solution gives ozonides; that can be split by boiling with water to the corresponding aldehyde.

“Jedoch scheint eine weitere Abspaltung von Kohlenstoff, also z. B. in dein vorliegenden Falle beim Safrol, unter Bildung von Piperonal bezw. Piperonylsäure nicht stattzuhaben.“

(I cannot manage to translate this, sorry!)

The yield of homopiperonal/homopiperonylic acid was 50%.

[1] Azione delia soluzione aquosa di acetato mercurico, Rome 1905.
[2] Reports 41, 2185 (1908).

Remind me never to volunteer to translate German again; I had forgotten much more than I thought blush I hope someone can correct me if I've made any errors smile

Video meliora proboque; Deteriora sequor. -Ovid

ylid
(Newbee)
04-21-03 15:07
No 428394
User Picture       Reduction of allylbenzene ozonide using Zn/AcOH

Here is the text of an old reference that uses Zn/AcOH to reduce the products of ozonolysis of an allylbenzene to the acetaldehyde. It contradicts a previous process Patent DE097620 which claimed that ozonolysis of safrole in AcOH, followed by decomposition using H₂O, yields piperonal.

Behavior of phenols and phenol ethers with unsaturated side chains towards ozone.
Harries C, Haarmann R. Ber. (1915) 48:32-41.

The present work has cleared up the apparent contradiction in the results of Otto and Verley (Ann. chim. phys. (1898) 13:120), who obtained vanillin from isoeugenol and O₃, and those of Witt, who tested the patent of Otto and Verley Patent DE097620 for the German Patent Office. Witt's lack of success, as also that of a French firm which attempted to prepare vanillin on a commercial scale by this method, was due to the use of too concentrated O₃. It has also been found that the usual direct decomposition of the ozonides, also that by means of Al-Hg in Et₂O (Ber. (1906) 38:2850), does not lead to the desired result; this was finally effected by means of Zn dust and AcOH in well cooled Et₂O.

The O₃ used (1.02%) was prepd. by passing 14% O₃ through 5% NaOH, then concentrated H₂SO₄ and finally a 40cm P₂O₆ tube. 5g isoeugenol in 250ml hexane saturated with this O₃ gives a yellow, slightly explosive syrup having, after precipitation from AcOEt-petroleum ether and drying in vacuo, the composition of the normal ozonide, C₁₀H₁₂O₅. Further concentration of the hexane in vacuo at 20°C gave a small amount of a highly explosive yellowish oil.

From 20g isoeugenol in 160g AcOH saturated with O₃, then heated 15 min. on the H₂O bath, freed from AcOH in vacuo and fractionated, were obtained a yellow oil, b12 150-200°C, and 8g tarry residue; the oil, on repeated fractionation, gave 7.0g pure vanillin (yield, 37.8%).

The same mixture, treated with dry O for 120h, yielded 4.1g unchanged isoeugenol, 4.6g dark oil (a), b18 148-240°C, 1.3g dark oil (b), b18 240-60°C, and 10g brown tarry residue. (a) could not be made to solidify but that it contained vanillin was shown by the fact that it easily formed the p-nitrophenylhydrazone. The yield of vanillin was therefore at least 12%.

20g isoeugenol in 1kg AcOEt was saturated with O₃, freed from the AcOEt in vacuo at 20°C, taken up in 300ml Et₂O, treated gradually with 120g pure Zn dust (Merck) and 60g AcOH, filtered, shaken for some hours with 100g precipitated CaCO₃ and 200ml H2O, the Et₂O layer seperated, the aqueous solution again shaken out with Et₂O, the combined Et₂O extracts evaporated and fractionated under 12mm; this gave 2g isoeugenol, 13g vanillin (yield, about 71%) and 3g tar; the yield of vanillin is considerably increased by distilling under 0.3-0.5 mm.

Acetisoeugenol, even with 1% O₃ in very dilute AcOEt solution, takes up more than the calculated amount of O₃; the product, twice precipitated from AcOEt-petroleum ether, solidifies in vacuo to a crystalline mass showing the ozonide reactions and containing 47.53-8.34% C and 5.02-5.04 H; on decomposition with AcOH it gives acetvanillic acid in not very large yield.

Eugenol ozonide (Riedl, Diss. Kiel 1911), an oil considerably more explosive and stable than the iso compound, when heated with AcOH, gives a brown oil, b0.5 120-200°C, that immediately resinifies. When, however, 40g eugenol is ozonized as above and treated with Zn dust and AcOH, it gives 6.0g eugenol, a little tar, and 17.7g homovanillin, b0.4 108-26°C, which on further fractionation yielded 8.5g thick oil, b0.43 111-4°C, showing a milky turbidity which could not be removed by repeated distillation.

Analysis showed that it probably contained a little peroxide (found, 64.28% C and 5.98% H). It at once oxidizes fuchsin-SO₂ in MeOH, reduces cold Fehling solution, dissolves in very dilute NaOH with light yellow color, at once resinifies with more concentrated NaOH. p-Nitrophenylhydrazone, dark yellow needles from alcohol, mp 150°C. Semi-carbazone, prisms from MeOH, mp 173°C. Oxime, leaves or needles from AcOEt, mp 115°C. With NaHSO₃ is at once obtained a difficultly soluble, white powdery double compound, which, apparently, does not have the normal comp. Aceteugenol yields a normal ozonide, C₁₂H₁₄O₃, tablets and needles from Et2O, m. 63°C. Decomp. with AcOH gave an oil, apparently containing, besides vanillin, acethomovanillin (p-nitrophenyl-hydrazone, light yellow leaflets, mp 179°C), and a solid, acethomovanillic acid, mp 134°C. Methyleugenol ozonide (Majima, C. A. 4, 203) on decomposition in AcOH gives only methylvanillin, but with Zn dust and AcOH is obtained methylhomovanillin, b0.4 112-3°C, light yellow, reddens fuchsin-SO₂, reduces Fehling solution; p-nitrophenylhydrazone, mp 157°C; semicarbazone, mp 181°C.

Who do you believe, me or your own eyes?

ylid
(Newbee)
04-21-03 15:29
No 428397
User Picture       Reduction of allylbenzene ozonides using Pd/C

Another way of getting to the acetaldehyde.

Homovanillin
Challis AAL, Clemo GR. (1947) J. Chem. Soc. 1692-7.

O-Carbethoxyeugenol (10g) in 100ml AcOEt, cooled to -70°C, treated 6h with 5% O₃ at 50cc/min, the ozonide hydrogenated in the presence of Pd-C, and the residue in ether washed with saturated NaHCO₃ (0.1g O-carbethoxyhomovanillic acid (I), mp 125-6°C), gives 7.5g O-carbethoxyhomovanillin (II), b2 150-5°C (2,4-dinitrophenylhydrazone, yellow, mp 129-30°C; p-nitrophenylhydrazone, orange-red, mp 85-6°C). II (4.5g) in 75ml absolute EtOH, treated with 1.5g HCl and heated 1h at 60°C, gives 3.2g homovanillin (III), b2 147-9°C.

Who do you believe, me or your own eyes?

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	All 7 posts		Subject: 3,4-Methylenedioxyphenylacetaldehyde, etc.		Please login to post		Down


		Rhodium (Chief Bee) 02-13-03 23:49 No 407531				3,4-Methylenedioxyphenylacetaldehyde, etc.
						Homopiperonal und seine Derivate Berichte 41, 2751-53 (1908) Zur Unterscheidung derjenigen Bestandteile der ätherischen Öle, welche zur Benzolreihe gehören und in der Seitenkette eine Allyl- bezw. Propenylgruppe aufweisen, besitzen wir verschiedene Mittel: wir können nach. Balbiano¹durch Behandlung mit Quecksilberacetat usw. zu verschiedenen Derivaten kommen, je nachdem die Allyl- oder Propenylgruppe vorliegt; hierbei wird jedoch das Molekül als solches zuweilen angegriffen, und es gelingt nicht immer, das Ausgangsmaterial leicht zu regenieren; nach Semmler² kann man durch Behandlung mit konzentrierter Ameisensäure Propenylderivate zerstören, während sich die Allylverbindungen beim Kochen mit konzentrierter Ameisensäure nur wenig verändern. Oxydiert man hierher gehörige Propenylverbindungen, wie Anethol, Asaron, Isosafrol usw., mit Ozon, so erhält than die zugehörigen Aldehyde, also Anisaldehyd, Asaronaldehyd, Piperonal usw. Wir konnten nun feststellen, dass bei Oxydation der Bestandteile ätherischer Öle, die eine Allylgruppe aufweisen, wie Safrol, Eugenol usw., durch Ozon das Molekül ebenfalls an der doppelten Bindung angegriffen wird und die Oxydation unter bestimmten Vorsichtsmaßregeln nicht weiter geht. Hiernach lassen sich also die korrespondierenden Homoverbindungen, wie Homopiperonal, Homovanillin usw., gewinnen; nebenher entstehen natürlich die zugehörigen Säuren. Homopiperonal Je 7 g Safrol werden in der gleichen Menge Benzol gelöst und mit ~3g Wasser vermischt. Hierauf wird ein lebhafter Ozonstrom ~4 Stunden lang hindurchgeleitet; alsdann treibt man durch das Reaktionsprodukt Wasserdampf, wobei Benzol und unangegriffenes Safrol übergehen. Der durch Zersetzung des Ozonids zurückbleibende Aldehyd wird unter Aussalzen ausgeäthert und im Vakuum destilliert; die gleichzeitig entstandene Säure wird dein Äther durch Soda entzogen. Eigenschaften des Homopiperonals: Sdp₁₀ = 143-144°C, d20 = 1.295, nD = 1.57117. Der Aldehyd erstarrt alsbald und schmilzt, aus Methylalkohol umkrystallisiert, bei 69°C (Piperonal hat Schmp. 37°C). Der Geruch des Aldehyds ist von jenem des Piperonals deutlich verschieden, aber jedenfalls angenehm. Das Semicarbazon, in der üblichen Weise dargestellt, schmilzt, aus Methylalkohol umkrystallisiert, bei 189°C. Der Schmelzpunkt des Piperonal-semicarbazons liegt bei 236-238°C. Das Oxim zeigt den Sdp₁₀ = 180-181°C und schmilzt, aus Wasser umkrystallisiert, bei 124-125°C. Das Homopiperonylsäurenitril wurde durch Kochen dieses Oxims mit der dreifachen Menge Essigsäureanhydrid dargestellt und zeigt folgende Eigenschaften: Sdp₁₀ = 153-156°C, d20 = 1.231, nD = 1.53698. Aus diesem Nitril wurde durch Verseifen (1 g Nitril in 35g 10% alkoholischer Kalilauge) übergeführt in die Homopiperonylsäure. Die Säure wurde aus Wasser umkrystallisiert und schmolz alsdann bei 127°C. Ein Teil des Nitrils wurde reduziert zum Amin : Sdp₁₀ =146-148°C, d20= 1.225, nD =1.5620. Die ätherische Lösung dieses Amins gab mit einer ätherischen Lösung von Pikrinsäure ein sofort ausfallendes Pikrat, das bei 160°C unter Zersetzung schmilzt. Der Methylester der Homopiperonylsäure wurde aus der letzteren in Methylalkohol durch Einleiten von Chlorwasserstoff gewonnen; diese homopiperonylsäure war gleichzeitig neben dem Homopiperonal bei der Oxydation des Safrols mit Ozon entstanden. Der Methylester zeigte folgende Eigenschaften: Sdp₁₀ = 153-155°C, d20 = 1.246, nD = 1.534, Dieser Ester wurde zum Homopiperonylalkohol, in absoluten Alkohol mit Natrium reduziert: Sdp₁₀ = 156°C, nD = 1.54780. Der Alkohol erinnert im Geruch. an Ylang-Ylangöl. Das auf diese Weise dargestellte Homopiperonal ist frei von Piperonal, so dass die Oxydation des Safrols und analoger Allylverbindungen mit Ozon unter Lösung der doppelten Bindungen Ozonide liefert, welche sich beim Kochen mit Wasser in die zugehörigen Aldehyde spalten. Jedoch scheint eine weitere Abspaltung von Kohlenstoff, also z. B. in dein vorliegenden Falle beim Safrol, unter Bildung von Piperonal bezw. Piperonylsäure nicht stattzuhaben. Die Ausbeute an Homopiperonal bezw. Homopiperonylsäure beträgt ca. 50% der Theorie. [1] Azione delia soluzione aquosa di acetato mercurico, Rom 1905. [2] Berichte 41, 2185 (1908).



		Aurelius (Hive Addict) 02-19-03 19:17 No 409823				English version please?
						somebody?



		thallium (Newbee) 02-19-03 19:32 No 409829				I'll translate it if noone else is working on...
						I'll translate it if noone else is working on it:) Video meliora proboque; Deteriora sequor. -Ovid



		Aurelius (Hive Addict) 02-19-03 19:55 No 409834				greatly appreciated!
						Thanks!



		thallium (Newbee) 02-19-03 23:13 No 409890				Homopiperonal and its derivatives Report 41,... (Rated as: excellent)
						Homopiperonal and its derivatives Report 41, 2751-53 (1908) We have several different ways to separate allyl- and propenylbenzenes, occurring in essential oils, from each other: We can according to Babiano (1) react the oil with mercuric acetate to get derivatives corresponding to the allyl- or propenyl benzene; but the molecules are attacked in such a way that it is not always easy to recover them. According to Semmler (2) propenyl derivatives are destroyed by concentrated formic acid; while boiling allyl derivatives with concentrated formic acid only slightly changes them. If you oxidize the propenyl benzenes (like anethole, asarone, iso-safrole etc.) with ozone; you get the corresponding aldehydes (anisaldehyde, asaronealdehyde, piperonal etc.) We can now conclude that oxidation of the allyl benzenes (found in essential oils; like safrole, eugenole etc.) with ozone also attacks the double bond; and that the ozone won't react further, under the below mentioned conditions. Thus you get the corresponding homocompounds: homopiperonal, homovanilline etc.; in addition to the produced acids. Homopiperonal 7g safrole is dissolved in the same amount of benzene, and mixed with approx. 3g water. Ozone is bubbled lively thru for around 4 hours. Then steam is bubbled thru; which makes the benzene and unreacted safrole pass over to the receiver. The aldehyde (from the "destroyed" ozonide) is salted out of the liquid and separated from it. It is distilled in vacuum, and the acid from the reaction is separated by reacting it with Na2CO3. Properties of homopiperonals: bp10 = 143-144°C, d20 = 1.295, nD = 1.57117. The aldehyde solidifies immediately, and melts (crystals from methanol) at 69°C (Piperonal mp. 37°C). The smell of the aldehydes is easily separated from that of the piperonals; but still pleasant. The semicarbazone, prepared in the usual manner, melts (crystals from methanol) at 189°C. The melting point of the piperonal-semicarbazones is around 236-238°C. The oxim has a bp10 = 180-181°C, and melts (crystals from water) at 124-125°C. The homopiperonylacetonitrile is prepared by boiling one part of this oxim with three parts acetic anhydride. It has the following properties: bp10 = 153-156°C, d20 = 1.231, nD = 1.53698. This nitrile is reacted with alkali (1 g nitrile in 35g 10% KOH/ethanol) to create homopiperonylic acid. Mp (crystals from water) = 127°C. Some nitrile is reduced to the amine: bp10 =146-148°C, d20= 1.225, nD =1.5620. A solution of this amine in ether gave with a solution of picric acid in ether crystals of the picrate which melts with dec. at 160°C. The methylester of the homopiperonylic acid is prepared by dissolving the acid in methanol and bubbling HCl thru the solution. This homopiperonylic acid was also created during the oxidation of safrole with ozone. The methyl ester has the following properties: bp10 = 153-155°C, d20 = 1.246, nD = 1.534. This ester is reduced with Na in absolute alcohol to homopiperonylic alcohol: bp10 = 156°C, nD = 1.54780. This alcohol smells somewhat like Ylang-Ylang oil. The in this way prepared homopiperonal is free from piperonal; so the oxidation of safrole and allyl-analogues with ozone in solution gives ozonides; that can be split by boiling with water to the corresponding aldehyde. “Jedoch scheint eine weitere Abspaltung von Kohlenstoff, also z. B. in dein vorliegenden Falle beim Safrol, unter Bildung von Piperonal bezw. Piperonylsäure nicht stattzuhaben.“ (I cannot manage to translate this, sorry!) The yield of homopiperonal/homopiperonylic acid was 50%. [1] Azione delia soluzione aquosa di acetato mercurico, Rome 1905. [2] Reports 41, 2185 (1908). Remind me never to volunteer to translate German again; I had forgotten much more than I thought I hope someone can correct me if I've made any errors Video meliora proboque; Deteriora sequor. -Ovid



		ylid (Newbee) 04-21-03 15:07 No 428394				Reduction of allylbenzene ozonide using Zn/AcOH
						Here is the text of an old reference that uses Zn/AcOH to reduce the products of ozonolysis of an allylbenzene to the acetaldehyde. It contradicts a previous process Patent DE097620 which claimed that ozonolysis of safrole in AcOH, followed by decomposition using H₂O, yields piperonal. Behavior of phenols and phenol ethers with unsaturated side chains towards ozone. Harries C, Haarmann R. Ber. (1915) 48:32-41. The present work has cleared up the apparent contradiction in the results of Otto and Verley (Ann. chim. phys. (1898) 13:120), who obtained vanillin from isoeugenol and O₃, and those of Witt, who tested the patent of Otto and Verley Patent DE097620 for the German Patent Office. Witt's lack of success, as also that of a French firm which attempted to prepare vanillin on a commercial scale by this method, was due to the use of too concentrated O₃. It has also been found that the usual direct decomposition of the ozonides, also that by means of Al-Hg in Et₂O (Ber. (1906) 38:2850), does not lead to the desired result; this was finally effected by means of Zn dust and AcOH in well cooled Et₂O. The O₃ used (1.02%) was prepd. by passing 14% O₃ through 5% NaOH, then concentrated H₂SO₄ and finally a 40cm P₂O₆ tube. 5g isoeugenol in 250ml hexane saturated with this O₃ gives a yellow, slightly explosive syrup having, after precipitation from AcOEt-petroleum ether and drying in vacuo, the composition of the normal ozonide, C₁₀H₁₂O₅. Further concentration of the hexane in vacuo at 20°C gave a small amount of a highly explosive yellowish oil. From 20g isoeugenol in 160g AcOH saturated with O₃, then heated 15 min. on the H₂O bath, freed from AcOH in vacuo and fractionated, were obtained a yellow oil, b12 150-200°C, and 8g tarry residue; the oil, on repeated fractionation, gave 7.0g pure vanillin (yield, 37.8%). The same mixture, treated with dry O for 120h, yielded 4.1g unchanged isoeugenol, 4.6g dark oil (a), b18 148-240°C, 1.3g dark oil (b), b18 240-60°C, and 10g brown tarry residue. (a) could not be made to solidify but that it contained vanillin was shown by the fact that it easily formed the p-nitrophenylhydrazone. The yield of vanillin was therefore at least 12%. 20g isoeugenol in 1kg AcOEt was saturated with O₃, freed from the AcOEt in vacuo at 20°C, taken up in 300ml Et₂O, treated gradually with 120g pure Zn dust (Merck) and 60g AcOH, filtered, shaken for some hours with 100g precipitated CaCO₃ and 200ml H2O, the Et₂O layer seperated, the aqueous solution again shaken out with Et₂O, the combined Et₂O extracts evaporated and fractionated under 12mm; this gave 2g isoeugenol, 13g vanillin (yield, about 71%) and 3g tar; the yield of vanillin is considerably increased by distilling under 0.3-0.5 mm. Acetisoeugenol, even with 1% O₃ in very dilute AcOEt solution, takes up more than the calculated amount of O₃; the product, twice precipitated from AcOEt-petroleum ether, solidifies in vacuo to a crystalline mass showing the ozonide reactions and containing 47.53-8.34% C and 5.02-5.04 H; on decomposition with AcOH it gives acetvanillic acid in not very large yield. Eugenol ozonide (Riedl, Diss. Kiel 1911), an oil considerably more explosive and stable than the iso compound, when heated with AcOH, gives a brown oil, b0.5 120-200°C, that immediately resinifies. When, however, 40g eugenol is ozonized as above and treated with Zn dust and AcOH, it gives 6.0g eugenol, a little tar, and 17.7g homovanillin, b0.4 108-26°C, which on further fractionation yielded 8.5g thick oil, b0.43 111-4°C, showing a milky turbidity which could not be removed by repeated distillation. Analysis showed that it probably contained a little peroxide (found, 64.28% C and 5.98% H). It at once oxidizes fuchsin-SO₂ in MeOH, reduces cold Fehling solution, dissolves in very dilute NaOH with light yellow color, at once resinifies with more concentrated NaOH. p-Nitrophenylhydrazone, dark yellow needles from alcohol, mp 150°C. Semi-carbazone, prisms from MeOH, mp 173°C. Oxime, leaves or needles from AcOEt, mp 115°C. With NaHSO₃ is at once obtained a difficultly soluble, white powdery double compound, which, apparently, does not have the normal comp. Aceteugenol yields a normal ozonide, C₁₂H₁₄O₃, tablets and needles from Et2O, m. 63°C. Decomp. with AcOH gave an oil, apparently containing, besides vanillin, acethomovanillin (p-nitrophenyl-hydrazone, light yellow leaflets, mp 179°C), and a solid, acethomovanillic acid, mp 134°C. Methyleugenol ozonide (Majima, C. A. 4, 203) on decomposition in AcOH gives only methylvanillin, but with Zn dust and AcOH is obtained methylhomovanillin, b0.4 112-3°C, light yellow, reddens fuchsin-SO₂, reduces Fehling solution; p-nitrophenylhydrazone, mp 157°C; semicarbazone, mp 181°C. Who do you believe, me or your own eyes?



		ylid (Newbee) 04-21-03 15:29 No 428397				Reduction of allylbenzene ozonides using Pd/C
						Another way of getting to the acetaldehyde. Homovanillin Challis AAL, Clemo GR. (1947) J. Chem. Soc. 1692-7. O-Carbethoxyeugenol (10g) in 100ml AcOEt, cooled to -70°C, treated 6h with 5% O₃ at 50cc/min, the ozonide hydrogenated in the presence of Pd-C, and the residue in ether washed with saturated NaHCO₃ (0.1g O-carbethoxyhomovanillic acid (I), mp 125-6°C), gives 7.5g O-carbethoxyhomovanillin (II), b2 150-5°C (2,4-dinitrophenylhydrazone, yellow, mp 129-30°C; p-nitrophenylhydrazone, orange-red, mp 85-6°C). II (4.5g) in 75ml absolute EtOH, treated with 1.5g HCl and heated 1h at 60°C, gives 3.2g homovanillin (III), b2 147-9°C. Who do you believe, me or your own eyes?

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