Diazoacetic acid, sodium salt

Diazoacetic Acid, (called Diazoessigsaure in Get), N2CH.COOH mw 86.05, N 32.56% The free acid is not stable, but it forms some metallic salts which are expl Potassium salt, KC2HN2O2, yel ndls or lemon-yel Iftlts, explodes violently with a loud noise on heating (Refs 1 2) and Sodium salt, NaC2HN202, yel cry Sts (from w), gm-yel ndls (from w + alc-eth), detonates on heating (Ref 1)... 

Curtius began work at Kolbe s suggestion on Dessaignes synthesis of hippuric acid (see p. 315) and at Baeyer s suggestion in Munich he used the ethyl ester of glycocoll, which he prepared. By the action of hydrochloric acid and sodium nitrite on this he discovered diazoacetic ester, the first aliphatic diazo-compound. He discovered hydrazine by the action of hot dilute acids on what he supposed was triazoacetic acid C3H3Ne(COOH)3, the sodium salt of which he obtained by the action of concentrated sodium hydroxide on diazoacetic ester.The starting material was later shown to be bisdiazoacetic... 

Hydrazine salts have been prepared by the action of hypochlorites on ammonia1 or urea 2 by the hydrolysis of salts of sulfohydrazimethylene disulfonic acid 3 by the hydrolysis of triazoacetic acid 4 by the reduction of diazoacetic ester 5 by the reduction of nitroguanidine followed by hydrolysis 6 by the reduction of the nitroso derivatives of hexamethylene tetramine 7 by the reduction of nitrates or nitrites with zinc in neutral solution 8 by the action of sodium bisulfite on hyponitrous acid... 

A [3 + 3] atom fragment method for the preparation of dihydro-1,2,4,5-tetrazines is the dimerization of diazo compounds under the influence of bases. In 1900 Hantzsch and Lehmann observed the formation of a new compound when ethyl diazoacetate (312) was treated with sodium hydroxide (00CB3668). The structure which they proposed originally was incorrect it was shown later that the product isolated was the disodium salt of l,2-dihydro-l,2,4,5-tetrazine-3,6-dicarboxylic acid (313) (or the 1,4-dihydro compound) <78HC(33)1075, p. 1078). 

Hydrazine salts have been prepared by the action of hypochlorites on ammonia (1) or urea (2) by the hydrolysis of salts of sulfohydrazimethylene disiilfonic acid (3) by the hydrolysis of triazoacetic acid (4) by the reduction of diazoacetic ester (5) by the reduction of nitroguanidine followed by hydrolysis (6) by the reduction of the nitroso derivatives of hexamethylene tetramine (7) by the reduction of nitrates or nitrites with zinc in neutral solution (8) by the action of sodium bisulfite on hyponitrous acid followed by reduction (9) by the reduction of K2S03N202 (10) by the action of ammonia on dichlorourea (11) by the reduction of nitrosoparaldimin (12) by the action of copper sulfate on ammonia at high temperatures (13) by the reduction of methylene diisonitrosoamine (14) by the hydrolysis of the addition product of diazoacetic ester and fumaric or cinnamic esters (15). 

The total synthesis started with a Birch reduction of p-methoxytoluene (382) to obtain the dihydro compound 383, which was treated with p-toluenesulfonic acid to obtain acetal 384. CyclopropanatiOTi with ethyl diazoacetate and transaceta-lization led to compound 385, which reacted to the unsaturated keto ester 386 on treatment with base. In the next step, the keto ester 386 was methylated with methylmagnesium chloride, and it reacted selectively at the 2-positon to yield 387. Lactonization with further methylation with methyl iodide afforded homo-lactone 389, which reacted with lithium salt 390 to alkyne 391 and was reduced with sodium borohydride to diol 392. Partial reductiOTi of the triple bond to the double bond was obtained with sodium in ammonia and further treatment with acid led to hydrolysis of the acetal, which subsequently cychzed to 394 (Scheme 8.1). 

---