Cyan-acetic acid

Cyan-acetic Acid.—Moore obtained at the positive pole carbon dioxide besides traces of nitrogen, and ethylene cyanide at the negative pole hydrogen and potassiuin hydroxide, bodies analogous to the decomposition products of sodium acetate. 

The procedure is as follows 200 c.c. of the oil are concentrated to 25 c.c. in a Wurtz flask under a pressure which should not exceed 15 mm. The 175 c.c. of terpenes contain a little citral, but the quantity is so small that it may be neglected. Ten c.c. of the residue, of which the specific gravity is known, are sh aken with a solution of 5 grms. cyan-acetic acid and 5 grms. ordinary EOH in 30 c.c. water in a small absorption flask with a long gi uated neck, and the non-absorbed residue read off as usual. (The specific gravity of citral is so near that of the concentrated oil used that it may M taken as identical.)... 

Finally a general approach to synthesize A -pyrrolines must be mentioned. This is tl acid-catalyzed (NH4CI or catalytic amounts of HBr) and thermally (150°C) induced tea rangement of cyclopropyl imines. These educts may be obtained from commercial cyan> acetate, cyclopropyl cyanide, or benzyl cyanide derivatives by the routes outlined below. Tl rearrangement is reminiscent of the rearrangement of 1-silyloxy-l-vinylcyclopropancs (p. 7 83) but since it is acid-catalyzed it occurs at much lower temperatures. A -Pyrrolines constitut reactive enamines and may be used in further addition reactions such as the Robinson anei lation with methyl vinyl ketone (R.V. Stevens, 1967, 1968, 1971). 

Methyl Malonate.—This ester is an artificially prepared body, having a fruity odour, somewhat similar to the above-described esters of the fatty acids. It has the formula CH2(C02CHg)2, and boils at 181°. It may be prepared by treating potassium cyan-acetate with methyl alcohol and hydrochloric acid. On saponification with alcoholic potash it yields malonic acid, which melts at 132°, and serves well for the identification of the ester. 

The next higher hydroxy acid is hydroxy acetic acid CH2(OH)— COOH, known also as glycolic acid. It may be prepared (a) from chlor acetic acid, (b) from the cyan-hydrine obtained from formic aldehyde, or (c) hy the oxidation of ethylene glycol, by reactions which have been already discussed. Its relation to ethylene glycol gives it the name of glycolic acid. It may be considered as a direct oxidation product of ethane. 

S3mthesis of Xanthine.— The synthesis of xanthine which is the immediate mother substance of theobromine, theophylline and caffeine has been accomplished as follows Starting with urea or carbamide, this is treated with cyano acetic acid in the presence of phosphorus oxychloride whereby the cyan acetyl radical is introduced into urea. The cyan acetyl urea by treatment with sodium hydroxide yields an isomeric imino compound. 

A. N. Dey (174) has described an independent synthesis of the alkaloids. Michael condensation of ethyl 7-ethoxy- or 7-phenoxy-crotonate (LI, R = OEt, R = Et or Ph) with ethyl malonate or cyan-acetate, followed by ethylation and hydrolysis, furnished a mixture of the two racemic forms of the glutaric acid, LII, which were separated by virtue of their different ease of anhydride formation. On treatment with hydrobromic acid, they gave rise to dl-homopilopic acid and dl-homo-isopilopic acid (LIII, R = OH), respectively. Corresponding methyl ketones (LIII, R = Me) were obtained by a similar synthesis from... 

In the electrolysis of cyan-acetic ester the formation of dicyan-succinic ester could not be observed likewise a union of the anions of benzyl-malonic ester, acetyl-malonic ester, and acetyl-dicarboxylic ester did not take place. Electrolysis of acid amides in the... 

Fig. 2 MS signal (black) for a 10 )iM reserpine solution (50 % methanol in water with 0.1% acetic acid) as a function of the applied voltage/ electrospray operating regime (Adapted with permission from Ref. [5], copyright American Chemical Society), (b) MS signal (black) and spray current (cyan) for a 5 pM leucine enkephalin solution (33 % acetonitrile in water with 1 % trifluoroacetic acid) as a function of applied voltage (Adapted with permission from Ref. [6], copyright American Chemical Society)...

The free OH can be modified by further chemical manipulation, and reaction with benzoyl chloride (BzCl) and pyridine (Py) gives 146 (the 0-benzyl group is in blue in the illustration). Treatment of 146 with 10% aqueous acetic acid cleaves the orthoester and gives a 1 1 mixture of hydroxy acetates 147 and 148, where the acetate units are marked in cyan. If 147 is isolated and treated with dihydropyran (see Chapter 26, Section 26.4.2) and an acid catalyst, the 2 -hydroxyl is converted to a dihydropyranyl ether (149) where the P3rranyl ether unit is marked in green. It is therefore possible to protect and deprotect the 5 -, 3 -, and 2 -hydroxyl groups selectively, although the abihty to differentiate the 2 - and 3 -hydroxyls is more difficrdt to achieve. 

Feiri-. ferric, ferri-, iron(III). -acetat, n. ferric acetate, iron(IIl) acetate, -ammonsulfat, n. ammonium ferric sulfate, -bromid, n. ferric bromide, iron(III) bromide, -chlorid, n. ferric chloride, iron(lll) chloride, -chlor-wasserstoff, -chlorwasserstoffsMure, /. fer-richloric acid. -cyan, n. ferricyanogen. -cyaneisen, n. ferrous ferricyanide (Turn-bull s blue), -cyanid, n. ferric cyanide, iron(III) cyanide ferricyanide. 

When heated with dilute sulphuric acid lactic acid is split into acetaldehyde and formic acid. The reaction resembles the reverse of the reaction of its formation from acet-aldehyde through the cyan hydrine. H H... 

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