Reimlinger, Hans K. published the artcile3(5)-Diazopyrazole, Application In Synthesis of 3553-12-6, the publication is Chemische Berichte (1961), 1036-41, database is CAplus.
3(5)-Aminopyrazole (I) prepared from pyrazole-3(5)-carboxylic acid hydrazide (II) gave with iso-AmONO the diazonium chloride (III). The diazotization in weakly acidic solution yielded the diazoamino compound III was converted in weakly alk. solution to the CHCl3-soluble unstable 3(5)-diazopyrazole (IV). III and IV gave with HI the 3(5)-iodopyrazole (V) and with 2-C10H7OH (VI) an O-free coupling product. Et 3(5)-pyrazolecarboxylate (342 g.) (from 300 g. N2CHCO2Et and C2H2) in 200 g. anhydrous N2H4 heated 8 h. on the water bath and evaporated in vacuo yielded 390 g. II, m. 166-8° (MeOH). II (390 g.) in 2.5 l. 2N HCl treated with stirring at 0° with solid NaNO2 in small portions gave 340 g. pyrazole-3(5)-carboxylic acid azide (VII), m. 158-60°. VII (340 g.) in 500 cc. absolute EtOH heated 24 h. on the water bath gave 299 g. Et N-[3(5)-pyrazolyl]urethane (VIII), m. 155-7° (MeOH). VIII (299 g.) and 920 g. Ba(OH)2.8H2O in 1.6 l. H2O refluxed 36 h., filtered, concentrated to half-volume, and extracted continuously with Et2O yielded 127 g. I, b1.5 115-16°, m. 38-40°. VIII (10 g.), 20 cc. concentrated HCl, and 10 cc. AcOH refluxed 10 h., evaporated in vacuo, the viscous residue dissolved in saturated aqueous Na2CO3, and the solution extracted continuously with Et2O yielded 5.3 g. N-Ac derivative of I, m. 22-3° (dioxane). I (3 g.) in 150 cc. MeOH saturated at 0° with HCl, filtered, the residue in 100 cc. MeOH treated during 5 min. with dry HCl and then with stirring at 0° with 10% excess iso-AmONO, and the mixture diluted after 1.5 h. with 250 cc. Et2O gave III, decomposed at 180-5°. I (3 g.) in 150 cc. 85% H3PO4 treated with stirring at 0° slowly with concentrated aqueous NaNO2 and then with saturated aqueous NaOAc yielded 3(5),3′(5′)-diazoaminopyrazole, C6H7N7, yellowish crystals, decomposed at 186-7.5° (MeOH-NH4OH). III (0.7 g.) in CHCl3 adjusted at 0° with 50 cc. saturated aqueous Na2CO3 to pH 8, the aqueous phase extracted with CHCl3, and the CHCl3 solution evaporated cold in vacuo gave long needles of IV, which decomposed rapidly at room temperature with the formation of brown insoluble products. III (1 g.) in 150 cc. CHCl3 treated at -10° with 3 cc. Et3N gave a solution of IV. IV in solution treated carefully with CHCl3 saturated with HCl yielded III. III (from 4 g. I) in a little H2O treated at 0° with 7 g. NaI in 150 cc. H2O, the mixture heated 0.5 h. on the water bath, evaporated in vacuo, and the residue extracted with Et2O yielded 6% V, needles, m. 72-3° (H2O). IV (from 1.2 g. I) in CHCl3 treated at 0° with 4 g. 68% HI, the mixture warmed to room temperature, and worked up in the usual manner gave V. A solution of III (from 3.5 g. I added dropwise at 0° to 12.5 g. VI in 10% aqueous NaOH) gave 2.8 g. coupling product, C13H8N4, yellow needles from much H2O, yellow-red platelets from aqueous MeOH, m. 192-4°; the filtrate gave addnl. product. IV solution from III in CHCl3 treated with concentrated VI in CHCl3 and evaporated also gave the coupling product, yellow-red leaflets, m. 192-4° (aqueous MeOH). The UV and IR absorption spectra of III and IV were recorded.
Chemische Berichte published new progress about 3553-12-6. 3553-12-6 belongs to pyrazoles-derivatives, auxiliary class Pyrazole,Amine,Amide, name is 3-Acetamidopyrazole, and the molecular formula is C5H7N3O, Application In Synthesis of 3553-12-6.
Referemce:
https://en.wikipedia.org/wiki/Pyrazole,
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