Knorr, by the action of ammonia on aceto-acetic ester, obtained (3-imidobutyric ester, which with nitrous acid yields a-isonitroso-(3-imidobutyric ester, CH 3 C(:NH) C(:N OH) CO 2 C 2 H 5.
Amino derivatives similarly result from thio-ureas and a-haloid ketones; the oxy derivatives from a-sulphocyanoketones by the action of caustic alkali; and the carboxylic acids from chloro-aceto-acetic ester, &c. and thioamides.
Of foremost importance are the reactions termed the malonic acid and the aceto-acetic ester syntheses; these are discussed under their own headings.
Aceto-acetic ester >>
ANTIPYRINE (phenyldimethyl pyrazolone) (C11H12N20), is prepared by the condensation of phenylhydrazine with acetoacetic ester, the resulting phenyl methyl pyrazolone being heated with methyl iodide and methyl alcohol to loo-110° C.: CH 0=N CH3 C-N CH3 >N C6H5 - II >N C6H6 CH 2 -CO HC-CO Phenyl methyl pyrazolone Antipyrine On the large scale phenylhydrazine is dissolved in dilute sulphuric acid, the solution warmed to about 40° C. and the aceto-acetic ester added.
Hantzsch has shown that aldehydes condense with aceto-acetic ester and ammonia to produce the homologues of pyridine, thus: R R [[Rooc Ch 2 Cho Ch 2 Coor Rooc C - Ch - C Coor]] + + 1 = Ii II +3H20.
Acetonyl acetone, CH 3 CO CH 2 CH 2 CO -CH a liquid boiling at 194° C., may be obtained by condensing sodium aceto-acetate with mono-chloracetone (C. Paal, Ber., 1885, 18, p. 59), CH3000H2C1+Na CH [[Coch3(Coor) ->Ch3co Ch2 Ch 000h,(Coor) -Ch3co]] CH2 CH2 000H3; or by the hydrolysis of diaceto-succinic ester, prepared by the action of iodine on sodium aceto-acetate (L.
Claisen by condensing ethoxymethylene aceto-acetic esters and similar compounds with /3-ketonic esters and with 1.3 diketones.
The ethoxymethylene aceto-acetic esters are prepared by condensing aceto-acetic ester with ortho-formic ester in the presence of acetic anhydride (German patents 77354, 79087, 79863).
C ACETO-ACETIC ESTER 6 11 10 O 3 or CH 3 ï¿½ CO.
Wanklyn have shown that pure ethyl acetate free from alcohol will not react with sodium to produce aceto-acetic ester.
Oc 2 H 5 H Chï¿½C]](ONa) :CHï¿½000C2H5; and on acidification this last substance gives aceto-acetic ester.
Aceto-acetic ester is a colourless liquid boiling at 181°C.; it is slightly soluble in water, and when distilled undergoes some decomposition forming dehydracetic acid C 8 H 8 0 4.
Scheele's green is a basic copper arsenite; Schweinfurt green, an aceto-arsenite; and Casselmann's green a compound of cupric sulphate with potassium or sodium acetate.
It is soluble in water, the solution showing an acid reaction, owing to the formation of aceto-acetic acid, and with alkalis it yields acetates.
The solution, known as baryta-water, finds an extensive application in practical chemistry, being used in gas-analysis for the determination of the amount of carbon dioxide in the atmosphere; and also being used in organic chemistry as a hydrolysing agent for the decomposition of complex ureides and substituted aceto-acetic esters, while E.
Hantzsch (Ann., 1882, 215, p. I; Ber., 1882, 15, p. 2914) which consists in the condensation of two molecules of aceto-acetic ester with one of an aldehyde and one of ammonia: RO 2 C CH 2 R' CHO CH 2 CO 2 R RO 2 C C CHR' C C02R CH 3 CO + NH 3 + CO CH 3 -' CH3 C-NH-C CH3 The resulting dihydro-compound is then oxidized with nitrous acid, the ester hydrolysed and the resulting acid heated with lime; carbon dioxide is eliminated and a trisubstituted pyridine of the type CH C(CH3) is obtained.
CH2 CHz?CU; CO CH 3 CO CH2 from sodio-malonic ester and 0-unsaturated ketones or ketonic esters: /CH, CO (R02C)2CH2+ Ph CH :CH /CH:>; CH(C02R) C07 from aceto-acetic ester and esters of a$-unsaturated acids, followed by elimination of the carboxyl group: CH2 CR', CH 3 CO CH 2.
Acids may be prepared by the action of dihalogen paraffins on sodio-malonic ester, or sodio-aceto-acetic ester (W.
C 6 H 7 0, is obtained by condensing sodium aceto-acetate with methylene iodide, the ester so formed being then hydrolysed.