Picrate salt

Thermal decomposition of the Meisenheimer zwitterion 88 gave rise to the 2-hydroxy-7-oxa-4-azoniaspiro[3.51-nonane picrate salt 90 by cleavage of the 1,3-dioxolane ring followed by intramolecular cyclization (Scheme 9) <2000RJOC706>. 

The relative inaccessibility of C-AIR (107) promoted Shaw and co-workers [66JCS(C)2270] to use the 5-aminoimidazole-4-carboxylate (111 R = H) as a model compound since this was readily obtained as a crystalline sodium salt, in two steps from ethyl Af-(cyano-ethoxycarbonylmethyl)for-mimidate (110) and cyclohexylamine (Scheme 12) [62JCS(C)2937]. 5-Amino-l-cyclohexylimidazole (112 R = H) was obtained as the picrate salt (22%) from the sodium salt of the acid (111 R = H) by treatment of... 

Thus, 5-amino-2-mercapto-l-methylimidazole (96 R = Me, R2 = SH) (65%) was obtained (48JCS2028) from 5-amino-2-methylaminothiazole (113 R1 = Me) on treatment with aqueous sodium carbonate. The aminoim-idazole (96 R1 = Me, R2 = SH) was found to be unstable in air, but gave a stable hydrochloride salt and on treatment with Raney nickel was desulfurized to give 5-amino-1-methylimidazole (96 R = Me, R2 = H) (58%), which was also unstable in air and was characterized as its picrate salt. 

CAS 555-77-1 817-09-4 (Hydrochloride salt) 6138-32-5 (Picrate salt) RTECS YE2625000... 

CAS 4368-28-9 39920-04-2 (Racemic mixture) 629653-73-2 (Acetate salt) 18660-81-6 (Citrate salt) 17522-62-2 (Formate salt) 4664-41-9 (Hydrobromide salt) 4664-40-8 (Picrate salt) 129497-92-3 (Trifluoroacetate salt)... 

Log ZTlp values for picrate salt complexes with crown ethers [77] in CDClj at 24°C ... 

Solutions were 2 x 10-3 mol dm-3 in compound, and potentials were determined with reference to the SCE, b Three-electron reversible oxidation process. Two-electron reversible oxidation process. Separation between anodic and cathodic peak potentials values for ferrocene under identical conditions ranged from 80 to 90 mV. Shift in respective ferrocenyl oxidation potential produced by presence of guest cation (2 equiv) added as their thiocyanate salts for potassium and ammonium, and their picrate salts for methylammonium and phenethyl-ammonium. 

The general trend is similar for the four hosts, although some discrepancy appears along these data. In spite of some systematic errors arising from the extraction method, it must be underlined for example the discrepancy of data for Ag. The silver(I) cation is much better extracted by the thioether-substituted host 12g probably because Ag can interact not only with the phosphorylated binding sites of the cavitand, but also with the thioether functionality of the lower rim. Furthermore, it must be pointed out that the Hpophihcity of the host can interfere in the extraction process. For both al-kahne and alkaline-earth picrate salts, the extractability increases with the... 

The reaction of aminoguanidine bicarbonate (84) with sodium nitrite in the presence of excess acetic acid produces 1,3-ditetrazolyltriazine (89), another nitrogen-rich heterocycle (C2H3N11 = 85 % N) which readily forms explosive metal salts. The reaction of aminoguanidine bicarbonate (84) with sodium nitrite in the presence of mineral acid yields guanyl azide (90), of which, the perchlorate and picrate salts are primary explosives. Guanyl azide (90) reacts with sodium hydroxide to form sodium azide, whereas reaction with weak base or acid forms 5-aminotetrazole. ... 

N02)2CH.CH2C8H4N mw 197-15, N21.32% erysts, mp 55-7°. Prepd by treating with 25% H202 and 93% HNOa a mixture of methylol-4-ethyl pyridines at 100°. There is a Picrate salt, mp 137°... 

Table 4. Free energies of binding of picrate salt guests to hosts at 298 K in CHCI3 saturated with H2O...

The complex of 11 with the short chain guest propanediammonium picrate has a relatively low because the guest cannot stretch in the cavity and coordinate to both crown ether rings simultaneously. For the longer chain picrate salt (n = 4), the crown ether bridges must fold slightly toward each other... 

Fig. 11. Schematic representation of complex formation between picrate salts of H3N(CH2) NH3 (n = 3-9) and 11. (Reproduced with permission from the American Chemical Society)...

To a flask containing 60 gm (1.0 mole) of urea is added 126 gm (1.0 mole) of methyl sulfate, and the stirred reaction mixture is warmed for 7 hr at 40°C. Stirring is continued until the reaction mixture is clear. The O-methylisourea is isolated as the picrate salt by adding 350-400 ml of 2 M lithium picrate in 300 ml of ethanol. The resulting mixture is boiled on the steam bath for 5 min. Most of the picrate dissolves but precipitates on slowly cooling to 0°C. The picrate is filtered, washed with ethanol, and air-dried to afford 182 gm (60%), m.p. 177°C. 

Addition of a second crown produces the loose ion pair A, Cr,K, Cr. However, the complexation constant for adding the second crown is 1800 M 1 for the fluorenyl carbanion and only 200 M 1 for the picrate salt. The lower value for picrate may in part be due to less charge delocalization, e.g., the free ion dissociation constant for potassium fluorenyl in TEF is 1.6 x 10 7M (18) as compared to 9.2 x 10 M for potassium picrate (17). The two N02 substituents close to the 0 bond in picrate may also hinder the enlargement of this ionic bond and the insertion of a crown ether molecule because of electronic or sterlc effects. 

As to salts, this last recipe above, taken from the literature, is the only claim of a valid hydrochloride salt of DMT. In the original synthesis, by Manske, the following description appears. "The hydrochloride could be obtained only as a pale yellow resin which, when dried in a vacuum desiccator over potassium hydroxide, became porous and brittle." I have found no attempts at its synthesis in the literature, and I have personally had no success at all. The picrate salt is well defined, used mostly for isolation and purification. The oxalate is used occasionally in animal studies. Early human studies involving the injection of solutions of the hydrochloride apparently made by dissolving DMT base in dilute aqueous HCI, and neutralizing this with base to achieve an end pH of appropriate 6. The fumarate is the salt specifically approved by the FDA for human studies, and this was the form used for human intravenous injection employed in the recent New Mexico studies. 

Bis (3 niiro-anilino)-rnethane, orn-yel ndls (from ale), mp 213° almost insol in ale insol in w, ether, chlf St benz. It was prepd by addg a 40% formaldehyde soln to a hot coned soln of 3 nitroaniline in ale. It forms a Picrate salt, Ci3Hj.2N404 +2CbH3N307, yel ndls, mp 120°(Ref 3, p 702)... 

Designolle and Brugere suggested that picrate salts could be used as a propellant, while in 1871, Abel proposed the use of ammonium picrate as an explosive. In 1873, Sprengel showed that picric acid could be detonated to an explosion and Turpin, utilizing these results, replaced blackpowder with picric acid for the filling of munition shells. In Russia, Panpushko prepared picric acid in 1894 and soon realized its potential as an explosive. Eventually, picric acid (1,2) was accepted all over the world as the basic explosive for military uses. 

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