1-heptaldehyde

Dissolve 57 g. of dry malonic acid in 92 5 ml. of dry P3rridine contained in a 500 ml. round-bottomed flask, cool the solution in ice, and add 57 g. (70 ml.) of freshly distilled n-heptaldehyde (oenanthol) with stirring or vigorous shaking. After a part of the aldehyde has been added, the mixture rapidly seta to a mass of crystals. Insert a cotton wool (or calcium chloride) tube into the mouth of the flask and allow the mixture to stand at room temperature for 60 hours with frequent shaking. Finally, warm the mixture on a water bath until the evolution of carbon dioxide ceases (about 8 hours) and then pour into an equal volume of water. Separate the oily layer and shake it with 150 ml. of 25 per cent hydrochloric acid to remove pyridine. Dissolve the product in benzene, wash with water, dry with anhydrous magnesium sulphate, and distil under reduced pressure. Collect the ap-nonenoic acid at 130-13272 mm. The yield is 62 g. 

Knoevenagel condensation of malonic acid with heptaldehyde [111-71-7] followed by ring closure, gives the fragrance y-nonanoic lactone [104-61-0] (6) (14). Beside organic synthesis, malonic acid can also be used as electrolyte additive for anodization of aluminum [7429-90-5] (15), or as additive in adhesive compositions (16). 

H-C-H 1 1 H-C-H 1 I H-C-H I Pyrolysis High heat Undecylenic acid, heptaldehyde... 

Pyrolytic Decomposition. The pyrolytic decomposition at 350—460°C of castor oil or the methyl ester of ricinoleic acid spHts the ricinoleate molecule at the hydroxyl group forming heptaldehyde and undecylenic acids. Heptaldehyde, used in the manufacture of synthetic flavors and fragrances (see Elavors and spices Perfumes) may also be converted to heptanoic acid by various oxidation techniques and to heptyl alcohol by catalytic hydrogenation. When heptaldehyde reacts with benzaldehyde, amyl cinnamic aldehyde is produced (see Cinnamic acid, cinnamaldehyde, and cinnamyl... 

In a 12-1. flask fitted with a mechanical stirrer and a short reflux condenser are placed 1800 g. (32.2 moles) of iron filings (Note i), 3 1. (52.5 moles) of glacial acetic acid, 3 1. of water, and 450 g. (3.95 moles) of heptaldehyde (Note 2). The mixture is heated on the steam bath, with stirring, for six to seven hours (Note 3). The flask is then fitted to an apparatus for steam distillation (Org. Syn. 2, 80) and the mixture distilled in a current of steam (Note 4) until no more oil passes over (7-8 1. of distillate). The oil is then separated, and the aqueous part distilled to recover a small quantity of dissolved or suspended heptyl alcohol. 

The heptaldehyde should be a freshly distilled product, boiling at 154-156°. 

Heptyl alcohol has been prepared by the reduction of heptaldehyde with zinc dust and acetic acid,i with sodium amalgam and acetic acid, with sodium in toluene and acetic acid, and with hydrogen and a platinum catalyst. Heptaldehyde has also been reduced biochemically by adding it to a fermenting sugar solution. Heptyl alcohol has been prepared by the reduction of heptoamide with sodium and amyl alcohol. ... 

It has been frequently noted that certain lots of iron filings are not satisfactory for the reduction of heptaldehyde to heptyl alcohol in acetic acid solution. E. E. Reld and J. R. Ruhoff have found that the addition of a solution of 20 g. of nickel cliloride hexahydrate in 50 cc. of water immediately after the addition of the aldehyde will cause the reaction to start at once and wiU greatly accelerate the rate of reaction so that it is complete in two hours instead of the usual six to seven hours. The checkers have found this to be the case even with a lot of iron which could not be made to react when reduced in hydrogen. It is also recommended that the reaction mixture be divided between two 12-I. flasks and that 3 1. of water be added to each half immediately at the end of the reaction. This prevents the mixture from setting to a hard mass in case the steam distillation is not carried out at once, and also reduces the amount of foaming. 

Cracking of the ester at about 500°C leads to the formation of the undecylenic acid ester together with such products as heptyl alcohol, heptanoic acid and heptaldehyde. Undecylenic acid may then be obtained by hydrolysis of the ester. Treatment of the acid by HBr in the presence of a peroxide leads to w-bromoundecanoic acid together with the 10-isomer, which is removed. Treatment of the w-bromo derivative with ammonia leads to w-aminoundecanoic acid, which has a melting point of 50°C (Figure 18.8). 

To a solution of 18.9 grams (0.166 mol) n-heptaldehyde in 25 ml of isopropanol is added, with stirring, a solution of 19,1 grams (0.166 mol) of 1-aminohydantoin in 110 ml water acidified with concentrated HCI. The heavy white precipitate formed is filtered and washed, until acid free, with small amounts of water and ether. The yield of N-(n-hBptylidenB)-1-aminohydantoin is 14 grams of MP 150°C (with decomposition). This may be recrystal-lized from dimethylformamide. 

Aldol condensation reactions have also been conducted. A good example is provided by Climent et al. (1998) for making a-n-amyl cinnamaldehyde (Jasmin aldehyde) by condensing benzaldehyde with n-heptaldehyde, in the presence of mesoporous MCM-41 aluminosilicates. Mesoporous silica-aluminas with a narrow range of pore diameter such as MCM-41 also... 

According to the submitters, methyl amyl ketone (800 g.) and ammonia (600 cc.) have been converted to 2-aminoheptane, b.p. 139-141°, in exactly the same manner, in 50-55 per cent yields. A slightly modified procedure was used in the preparation of w-heptylamine and furfurylamine. Heptaldehyde (320 g.) was dissolved in 500 cc. of methanol, and 150 cc. of liquid ammonia was added the reduction was conducted as above. w-Heptyla-mine, b.p. 57-58°/23 mm., was obtained in yields of 53-63 per cent. Freshly distilled furfural (290 g.) was dissolved in 500 cc. of methanol, 150 cc. of liquid ammonia was introduced, and the reduction carried out as usual. The product was removed, filtered, and fractionated directly. Furfurylamine, b.p. 144-146°, was obtained in 50 per cent yield. 

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