Picrolonic acid

Supplement 1936 3458-3793 Picrolonic acid, 51. Hydantoin, 242. Uracil, 312. Indigo, 416. Barbituric j acid, 467. Alloxan, 500. ... 

Analytical applications of pyrazolones have been reviewed by Busev et al. (65RCR237). Organic bases are easily characterized by formation of highly crystalline salts with picrolonic acid (l-(4-nitrophenyl-3-methyl-4-nitro-5-hydroxypyrazole). The last-named compound is used as a reagent for alkaloids, tryptophan, phenylalanine and for the detection and estimation of calcium (B-76MI40404). 

As expected, heterocyclic enols and potential enols (i.e, compounds existing mainly in the CH form) behave toward diazomethane similarly to the open chain and isocyclic enols, i.e. they form enol methyl ethers by reactions of the SnI type (cf. footnote 29). Examples of this behavior are barbituric acid, picrolonic acid, dchydroacetic acid (64), 3-methyl-l-phenylpyrazolin-5-one, 1-phenylpyrazoli-dine-3,5-dione, 1,2-diphenylpyrazolidine-3,5-dionc, 3-hydroxy-... 

Picrolonic Acid [l-(4-Nitro-phenyl)-4 nitro-3-methyl-Pyrazolone-(5)]. 

Wolfgang and Dodson in a further study suggested a method of separation using the picrolonic acid precipitation of Hg(I). In perchlorate media even with reactant concentrations as low as 10 M, complete exchange was always observed by these workers, except in the presence of added CN" ( [Hg(II)]) when the kinetics could be examined. With reactant concentrations in the ranges Hg(I) 6x 10 to 7x 10 M, and Hg(II) 1.6x 10 to 1.6x 10 M the rate law found was... 

Ethyl Cydopentanone Carboxylate Picrolonic Acid as-Diphenylethylene Amylene from acetone Xylose Glyoxal... 

Thiadiazoles are weak bases. They form readily hydrolyzable salts with mineral acids and addition compounds with heavy-metal salts. Amino-1,2,4-thiadiazoles also form salts with picric acid and picrolonic acid (65AHC(5)il9). 

Upon addition of hot aqueous solutions of picric acid or picrolonic acid to aqueous solutions of 1,4-oxatellurane 4,4-dihydroxide, the corresponding hydroxide picrate or picrolonate precipitated6. 

Picrolonic acid (or l-p-nitrophenyl-3-methyl-4-nitro-5-pyrazolone) reagent... 

Place a drop of the test solution (either neutral or acidified with acetic acid) in the depression of a warm spot plate and add 1 drop of a saturated solution of picrolonic acid. Characteristic rectangular crystals are produced. 

Picrolonic add (saturated). Shake 1 g picrolonic acid, C10H7O5N4, with S ml water, and use the clear supernatant liquid for the tests. 

Only a few 4-nitro-2-pyrazolin-5-ones are known. They are listed in Table XXIX. The best-known of these compounds is picrolonic acid, which is 4-nitro-3-methyl-l-(4-nitrophenyl)-2-pyrazolin-5-one. This compound is widely used to form salts of basic compounds for isolation or identification. The hydrogen atom at C-4 is acidic in the 4-nitro-2-pyrazolin-5-ones because of the two adjacent electron-withdrawing groups. This hydrogen is easily replaced by metals when treated with metal alkoxides1642 and reacts with diazomethane.478... 

The alkylation of 4-nitro-2-pyrazolin-5-ones at C-4 with diazomethane478 has already been mentioned. This hydrogen atom is also replaceable with bromine.1642 Reduction of the nitro group with stannous chloride forms the corresponding amine.478,480 Picrolonic acid condenses with itself to form a bis(2-pyrazolin-5-one) connected by a double bond at the 4,4 -position, with elimination of two moles of nitrous acid.690 Condensation also occurs in the presence of phenyl-hydrazine, but 4,4 -bis[3-methyl-l-(4-nitrophenyl)-2-pyrazolin-5-one] is formed.690... 

Phthalazinedione, 331-332 Phthaldehyde, 156, 157 Phthalaldehydic acid, 157 Phthalhydrazide, 332, 399 Phthalic acid, 190, 373 Phthalic anhydride, 427, 441 Picrolonic acid, 213 Pimaric acid, 190 Pinacolone, 79 Pinacolone, 79 10a-Pinane-2/5-ol, 169, 170 a-Pinene, 343 0-Pinene, 239, 362 a-Pinene oxide, 344 rra/w-Pinocarveol, 362 Piperidine, 28, 332 Pivalic acid, 353 Platinous chloride, 272 Platinum catalysts, 332-333 Podocarpic acid, 342... 

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