Nitro compounds ammonium formate

Formic acid is a good reducing agent in the presence of Pd on carbon as a catalyst. Aromatic nitro compounds are reduced to aniline with formic acid[100]. Selective reduction of one nitro group in 2,4-dinitrotoluene (112) with triethylammonium formate is possible[101]. o-Nitroacetophenone (113) is first reduced to o-aminoacetophenone, then to o-ethylaniline when an excess of formate is used[102]. Ammonium and potassium formate are also used for the reduction of aliphatic and aromatic nitro compounds. Pd on carbon is a good catalyst[103,104]. NaBH4 is also used for the Pd-catalyzed reduction of nitro compounds 105]. However, the ,/)-unsaturated nitroalkene 114 is partially reduced to the oxime 115 with ammonium formate[106]... 

Ttinitroparaffins can be prepared from 1,1-dinitroparaffins by electrolytic nitration, ie, electrolysis in aqueous caustic sodium nitrate solution (57). Secondary nitroparaffins dimerize on electrolytic oxidation (58) for example, 2-nitropropane yields 2,3-dimethyl-2,3-dinitrobutane, as well as some 2,2-dinitropropane. Addition of sodium nitrate to the anolyte favors formation of the former. The oxidation of salts of i7k-2-nitropropane with either cationic or anionic oxidants generally gives both 2,2-dinitropropane and acetone (59) with ammonium peroxysulfate, for example, these products are formed in 53 and 14% yields, respectively. Ozone oxidation of nitroso groups gives nitro compounds 2-nitroso-2-nitropropane [5275-46-7] (propylpseudonitrole), for example, yields 2,2-dinitropropane (60). 

Hydrogen gas can be replaced by ammonium formate for the reduction of nitro compounds to amines. The ammonium formate method is efficient, and the rapid workup procedure by simple filtratkin makes it widely used for converting the NO to the NH. ° For example, ct-nitro esters are reduced to ct-amino esters in excellent yields on treatment v/ith HCO NH and PdAZ in methanol. ... 

Zinc in the presence of ammonium chloride reduces primary, secondary and tertiary aliphatic nitro compounds but yields of hydroxylamines are moderate and formation of coupling products is common. Zinc with or without ammonium chloride reduces aromatic nitro compounds (e.g. 75, equation 49) into hydroxylamines in moderate to good yield. However, it has been mentioned that the reaction is sensitive to the grade and quality of zinc dust (equation 50) and aromatic amines have been obtained as major products in zinc reduction reactions. ... 

The particularly good activity against protein kinases of a-aminoquinazoline derivatives is borne out by their activity against both in vitro and in vivo models of human tumors. The examples that follow are but two of a number of compounds from this structural class that have emerged from the focus that has been devoted to this stmctural class. Nitration of the benzoate (78-1) with nitric acid affords the nitro derivative. Hydrogenation converts this to the anthrandate (78-2). In one of the standard conditions for forming quinazolones, that intermediate is then treated with ammonium formate to yield the heterocycle (78-3). Reaction of this last product with phosphorus oxychloride leads to the corresponding enol chloride (78-4). Condensation of this last intermediate with meta-iodoanUine (78-5) leads to displacement of chlorine and the consequent formation of the aminoquinazoline... 

Clemmensen-type reduction.1 Aromatic ketones can be reduced to the corresponding methylene compounds with ammonium formate on transfer hydrogenation in acetic acid catalyzed by 10% Pd/C. The reduction is usually complete in 10-30 minutes at 110°. Halo and nitro substituents can be reduced under these conditions, and a,p-unsaturated carbonyl groups are reduced to saturated carbonyl groups. 

Nitro compounds are easily reduced, catalytically or chemically, to amino compounds. Incomplete reduction can lead to a hydroxylamino derivative or to binuclear azo, azoxy, and hydrazo compouds, e.g., 789 790, 791. Examples include reduction of 3-nitropyridines using aqueous sodium hydrosulfite at room temperature <2005JME5104> and of 2-nitropyridine by transfer hydrogenation in the presence of 10% Pd/G and recyclable polymer-supported formate, prepared from aminomethylpolystyrene resin and ammonium formate <2005SC223>. A nitro group can be reduced in the presence of an A-oxidc group, e.g., 784 782. 

Partial reduction of aromatic polynitro compounds leads to nitro amines. The most successful reagents are the alkali metal or ammonium sulfides in aqueous alcoholIn some instances, sodium bicarbonate combined with sodium sulfide gives better results because of the formation of sodium hydrosulfide, which is believed to be the main reducing agent. Also, aqueous methanol is preferred to aqueous ethanol. Nitro compounds that are sparingly soluble in alcohol solutions may be reduced by hydrogen sulfide in pyridine solution. ... 

Catalyzed reductions with ammonium formate proceed with retention of configuration, at least for the case of nitro compounds. Treatment of steroid derivative (12) with ammonium formate in methanolic solution and a catalytic amount of palladium on charcoal gave exclusively amino steroid (13), as shown in equation (13). A similar technique has been used to produce members of the ephedrine family. 

The selective and rapid reduction of nitro compounds is an active area of research, particularly when other potentially reducible moieties are present in the molecules. Anhydrous ammonium formate has been developed as a catalytic hydrogen transfer agent for selectively reducing nitro groups in the presence of acid, ester, amide, halogen and nitrile groups (equation 13). ... 

The value of the catalytic transfer hydrogenation route is demonstrated by the selective, high yield and rapid reduction of nitro aliphatic compounds to their corresponding amine derivatives using anhydrous ammonium formate (equation 26). A wide variety of nitro compounds are reduced in the presence of other functional groups including acids, esters and nitriles. Furthermore, the method is stereospecific and proceeds with retention of configuration pure racemic syn-nitro alcohols (39a) and (39b) were converted to the 5yn-amino alcohols (40a) and (40b) and the axial nitrosteroid (41a) afforded the 63-amine (41b). 

Reduction The stable Ni(0) complex is a useful catalyst for reduction of carbonyl compounds (to alcohols), sulfonyl azides (to sulfonamides), imines and nitro compounds (to amines) with ammonium formate. 

Conversion of Phenols to Amines. Aniline and some diphenylamine are formed when phenol and NHs solution are heated under pressure in the presence of FeCh, Al(OH)s, or Fe(OH)j. When NH and phenol or ortho-or para-cresols are reacted in the vapor phase over an AljO catalyst, yields of up to 88 per cent of the corresponding amines are obtained. However, these amines are customarily obtained by reducing the parent nitro compound, except in cases where it is difficult to obtain the required nitro isomer. For example, it is considered that the amination of symr xylenol is the best method of preparing sym-xylidine (l-amino-3,5-di-methylbenzene). When sym-xylenol is heated under pressure to 320 C with ammonium chloride, about equal amounts of sj/m-xylidine and sym-dixylylamine (5-imino-bis-l,3-dimethylbenzene) are formed. The ortho-and para-nitrophenols and nitrocresols can be aminat more readily. 2-Nitro-p-cresol [OH(l), N02(2), CHj(4)] and o-nitrophenol have been aminated in aqueous ammonia containing ammonium salts of weak acids to inhibit decomposition. Phosphoric, boric, carbonic, and formic acids were used. In one case it is claimed that 55-65 per cent yields of 2-nitro-p-toluidine (MNPT of commerce) were obtained when 2-nitro-p-cresol, 28 per cent aqueous NHj, and monoammonium phosphate, 1 11.5 0.2 molar ratio, were heated under pressure for 10 hr at 140-150°C and then 5 hr at about 160 C. Earlier workers, employing somewhat similar conditions, claimed excellent yields of MNPT when 1 mole of ammonium formate was used per mole of 2-nitro-p-cresol. ... 

Several modifications of this reduction involve formates and are effective for reduction of various functional groups. A mixture of formic acid and ethyl magnesium bromide was used to reduce decanal to decanol in 70% yield. Decanal was also reduced to decanol in 69% yield by using sodium formate in N-methyl-2-pyrrolidinone as a solvent. Functional groups other than carbonyl derivatives can be reduced under relatively mild conditions with formate derivatives. Ammonium formate, in the presence of palladium on carhon was used to reduce an azide to a primary amine.Aliphatic nitro compounds are also converted to an amine with this reagent. l°... 

Gowda, D. C. Mahesh, B. Catalytic transfer hydrogenation of aromatic nitro compounds by employing ammonium formate and 5% platinum on carbon. Synth. Commun. 2000, 30, 3639-3644. 

To introduce additional diversity, the 3-nitrophenyl and 4-nitrophenyl derivatives in the R position were further functionalized. For example, the nitro group and enol ether of 3-nitrophenyl 39 were reduced, and the resulting aniline was acylated to give 41 (Scheme 7.9). Alternatively, selective reduction of the nitro group worked most effectively in the presence of ammonium formate to give compounds 42. 

Pd-catalyzed reactions of allylic esters such as aUyl acetates, carbonates, and phosphates with soft carbon nucleophiles such as malonate esters are useful for carbon-carbon bond formation (Sects. V.2.1.1-V.2.1.5). hi this section, Pd-catalyzed substitution reactions of nitrogen-containing allylic derivatives such as allylic amines, ammonium salts, tosylim-ides, and nitro compounds are described (Scheme 1). The allylic derivatives of other group 15 atoms have never been used as allyl unit source in Pd-catalyzed alkylation reactions so far. 

Scheme 8.11 Photocatalytic leductirai of nitro compounds to amino compoimds in water with the addition of ammonium formate (HCOONH4) for quenching photogenerated holes under N2 atmosphere...

Co -", Ni "", Cu -", and Zn ) [73], GR-Pd-CdS [76], and hierarchical CdS-ZnO-GR hybrids [108]. It is found that their photoactivities for reduction of nitro compounds to amino compounds with ammonium formate (HCOONH4) for hole scavenger in N2 atmosphere (Scheme 8.11) under visible light irradiation are all remarkably enhanced as compared to the blank semiconductors [73,100-102,106, 107]. It has been concluded that the selective reduction efficiency can be driven by appropriate introduction of GR into the matrix of pure semiconductor, which can boost the transfer and prolong the lifetime of the electrons photoexcited from the semiconductor due to the tighter connection between GR and the semiconductor, as well as the optimization of the atomic charge carrier transfer pathway across the interface between GR and the semiconductor. 

Saha A, Ranu B (2008) Highly chtanoselective reduction of aromatic nitro compounds by copper nanoparticles/ammonium formate. J Org Chem 73 6867-6870... 

Reduction of the nitro group in 70 with zinc in hot sodium hydroxide results in formation of pyrrolo[2,l-(f][l,2,5]benzotriazepine 71 by intramolecular coupling of the amino group with the newly formed nitroso group (Scheme 16). If the reduction is carried out under the less rigorous conditions of zinc in aqueous ammonium chloride the intermediate hydroxy compound is formed <96T10751>. 

---