Nitro-acids

The nitration of phthalic anhydride with a mixture of concentrated sulphuric and nitric acids yields a mixture of 3-nitro- and 4 nitro phthalic acids these are readily separated by taking advantage of the greater solubility of the 4 nitro acid in water. Treatment of 3 nitrophtlialic acid with acetic anhydride gives 3 nitrophthahe anhydride. 

The mother liquors from the washings and recrystallisations are saved for the recovery of the 4-nitrophthalic acid. The combined mother liquors ore concentrated to a small bulk and the acid is extracted with ether. Upon esterification by the Fischer - Speier method, the 3-nitro acid forms only the acid ester and may be removed by shaking the product with sodium carbonate solution, whilst the neutral ester of 4-iiitrophthalic acid remains unaffected. Hydrolysis of the neutral ester gives the pure 4-nltrophthalio acid, m.p. 165°. 

Thiophene, 2-methyl-5-(mesitylsulfonyl)-Truce-Smiles rearrangement, 4, 825 Thiophene, 2-methyl-3-nitro-acidity, 4, 799... 

Nitro-pJienols and Nitro-acids dissolve in ctiustic alkahs as a rule with a deep yellow or orange colour. On reduction with st. innous chloride or zinc dust, as described above, they yield the amino-derivatives. In the case of the amino-phenol, the solution is made alkaline with caustic soda, satuiated with CO.j, salt added and extracted w ith ether. In the case of the amino-acid, the method used is that desciibed under Prep. 91 (p. 201). 

Alicyclic hydroxamic acids undergo several specific oxidative cleavage reactions which may be of diagnostic or preparative value. In the pyrrolidine series compounds of type 66 have been oxidized with sodium hypobromite or with periodates to give y-nitroso acids (113). Ozonolysis gives the corresponding y-nitro acids. The related cyclic aldonitrone.s are also oxidized by periodate to nitroso acids, presumably via the hydroxamic acids.This periodate fission was used in the complex degradation of J -nitrones derived from aconitine. 

Because the anioas of nitroalkanes are stable, retro-acyladoc smoothly In the presence of a base catalyst. This type of reacdo organic synthesis." Nucleophilic attack of water or alcohol to ct-the ring cleavage v/ith the formadon of Oj-nitro acids and Oj-niti... 

Nitrosylsulfuric Acid (Nitroso, Nitrosyl Sulfate, Nitrosulfuric Acid, Nitroxylsulfuric Acid, Nitro-sulfonic Acid, Nitrosyl Hydrogen Sulfate, Nitro Acid Sulfite). HNOs S, NO HS03, HNOS04, ONOSO3H, mw 127.08, N 11.02%, colorl prisms mp, decomps 73.5°. In moist air the crysts decomp with the formation of sulfuric and nitric... 

Here too there is an enol that tautomerizes to the product. The mechanism is illustrated for the case of P-keto acids, ° but it is likely that malonic acids, a-cyano acids, a-nitro acids, and P,y-unsaturated acids behave similarly, since similar six-membered transition states can be written for them. Some a,P-unsaturated acids are also decarboxylated by this mechanism by isomerizing to the p,y-isomers before... 

Explosive decomposition occurred during attempted vacuum distillation, attributed either to the presence of some trinitro compound in the unpurified dinitrophenylacetic acid used, or to the known instability of o-nitro acid chlorides. A previous publication (ibid., 407) erroneously described the decomposition of 2,4-dinitrobenzoyl chloride. 

In 2008, Chakraborty el al. reported that Michael addition of nitromethane to the sugar olefinic derivative 36 provided the sugar-based (I-nitro acid ester 37 (Scheme 14), which was used as starting material for the preparation of a novel type of cyclohexyl amines.36... 

Intramolecular Henry reactions of nitro sugars are usually diastereo-selective sometimes a single isomer results from an epimeric mixture, on account of the reversivility of the Henry reaction, which allows equilibration through open chain intermediates.49 A recent example involving the D-glucose derived nitro acid ester 26 is shown in Scheme 22. 

It may be mentioned in passing that Chapman and coworkers148 determined rate coefficients for the reactions at 30 °C of phenylacetic acid and various meta- or /zara-substituted phenylacetic acids with DDM in 10 alcohols as solvents. The nitro acids were included. There were some interesting indications of solvent dependence for the apparent a values of /zara-substituents, including N02, for which values ranging from 0.69 to 0.77 were... 

Recently, time-resolved resonance Raman spectroscopic studies47 of the excitation of 2-(2, 4 -dinitrobenzyl)-pyridine 58 and 4-(2, 4 -dinitrobenzyl)pyridine have shown that three transient intermediates are involved they are aci-nitro acid 59, aci-nitro anion 60 and N—H... 

Etbyl-3-nitrobenzoate, monoclinic prisms, mp 47°, bp 296° It may be prepd by saturating an ale soln of the acid with. HCl gas from the acid salt of 3 nitrobenziminoethylether from the 3-nitro acid and diazoethane and from the >nitro benz in bulling abs ale and HCl gas Ref Beil 9, 378, (151), (154) [248] Etbyl 4-nitrobenzoate, pi tits (from ale), mp 57°. It may.be prepd from the acid in ale in the presence of HCl, from the methyl ester and excess ale in the presence of KOCH3 Ref Beil 9, 390 [258]... 

Cyclization to the hexahydro-l,4-benzodiazocinone (204) was carried out in 60% yield by hydrogenation of the nitro acid (203) and carbodiimide dehydration. The diamine (205) was obtained by hydride reduction (71CJC2023). 

The presence of nitrates in the solution will cause the formation of nitro acids when the final acidification takes place. 

Hydrolysis of the ester is achieved by refluxing in aqueous N or 2N NaOH solution until the insoluble ester dissolves. The solution is then cooled, and the alcohol is extracted into a suitable solvent, e.g. ether, toluene or alcohol-free chloroform. The extract is dried (CaSO4, MgSO4) and distilled, then fractionally distilled if liquid or recrystallised if solid. (The nitro acid can be recovered by acidification of the aqueous layer.) In most cases where the alcohol to be purified is readily freed from ethanol, the hydrolysis of the ester is best achieved with N or 2N ethanolic NaOH or 85% aqueous ethanolic N NaOH. The former is prepared by dissolving the necessary alkali in a minimum volume of water and diluting with absolute alcohol. The ethanolic solution is refluxed for one to two hours and hydrolysis is complete when an aliquot gives a clear solution on dilution with four or five times its volume of water. The bulk of the ethanol is... 

Kinetic template effects have been postulated in more typical organic aldol condensations, where metals such as lithium and zinc are likely to coordinate both the enolate or enamine nucleophile and the aldehyde in the transition state. The examples shown in Schemes 58184 and 59185 are illustrative of these reactions and the degree of selectivity obtained. The carboxylation of ketones and nitroalkanes by methyl magnesium carbonate to produce P-keto acids and a-nitro acids respectively provides early examples of similar reactions (Scheme 60).186 187 See also Section 61.1.4.4. 

The terminal nitroso group in perfluorinated m-nitroso aliphatic carboxylic acids is readily oxidized by hydrogen peroxide and also by dinitrogen tetroxide to give nitro acids 11.250... 

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