Formamides nitro compounds

In the examples, a nitro group is substituted for a hydrogen atom, and water is a by-product. Nitro groups may, however, be substituted for other atoms or groups of atoms. In Victor Meyer reactions which use silver nitrite, the nitro group replaces a hahde atom, eg, I or Br. In a modification of this method, sodium nitrite dissolved in dimethyl formamide or other suitable solvent is used instead of silver nitrite (1). Nitro compounds can also be produced by addition reactions, eg, the reaction of nitric acid or nitrogen dioxide with unsaturated compounds such as olefins or acetylenes. 

Nitroalkanes react with Jt-deficient alkenes, for example, p-nitro ketones are produced from a,P-unsaturated ketones [41], whereas allylic nitro compounds have been prepared via the Michael-type addition of nitroalkanes with electron-deficient alkynes (Table 6.19). The reaction in either dimethylsulphoxide [42] or dimethyl-formamide [43] is catalysed by potassium fluoride in the presence of benzyltriethyl-ammonium chloride the reaction with dimethyl acetylenedicarboxylate is only successful in dimethylsulphoxide [42], Primary nitroalkanes produce double Michael adducts [42,44], A-Protected a-aminoacetonitriles react with alkynes under catalysed solidiliquid conditions to produce the Michael adducts [45] which, upon treatment with aqueous copper(Il) sulphate, are converted into a,p-unsaturated ketones. 

Some studies seeking preferred conditions for this reaction have been made. Optimum yields are obtained when the amount of water present is appreciable, and it was noted that the rate of hydrogen evolution increases with increasing water content. A 75% formic acid system appears generally preferred. Under the reaction conditions examined by the submitters, olefins, ketones, esters, amides, and acids are inert, but nitro compounds are reduced to the formamide derivative. 

In addition, manganese oxide oxidizes benzylic methyl or methylene to carbonyl [814] and cleaves the carbon bonds of vicinal diols [577, 522]. It converts amines into imines [577, 525] tertiary amines into secondary amines [572], formamides [526, 527, 525], or ketones aromatic primary amines [575, 525] and hydrazo compounds [525] into azo compounds hy-droxylamines into nitroso [576] or nitro compounds [525] hydrazones into diazo compounds [520] phosphines into phosphine oxides [575] thiols into disulfides [576] and sulfides into sulfoxides [541]. 

Nickel-aluminum/formic acid Formamides from nitro compounds... 

Very little has been done on the use of iron compounds in the synthesis of carbamates and ureas from nitro compounds. It has long been known [191] that heating aliphatic nitro compounds with an excess of Fe(CO)s (1.4 mol for 1.0 mol of nitro compound) in diglyme at 120-132 °C for 15-17 h affords low yields of formamides and ureas, but the yield of urea is at best 18.5 % (in the case of nitrocyclohexane yields were even lower for 1- or 2-nitropropane, 2-methyl-2-nitropropane, and 1-nitroadamantane). These experiments were among the first... 

Primary, secondary, and tertiary aliphatic nitro compounds give formamides and ureas in modest yields by reaction with Fe(CO)s in dry diglyme at 120-135 °C for 15-17 h (eq. 22) [123] ... 

Hydrocarbonylation of aromatic nitro compounds yields the corresponding aromatic formamides [74] ... 

Nitrous oxide is reduced by CO in the presence of [Rh(C0)2C1]2 and base to N2 and C02 21 The mechanism of the reduction of aromatic nitro compounds by CO to give isocyanates has been studied by IR the catalyst is trans-PdCl2(pyridine)2.212 PeiCOg, Ru3(C0)x2 Rh6(C0)xg convert ortho-nitrostyrenes and CO into indoles in up to 75 selectivity (eq.21).213 Nil2(PPh3)2 under CO pressure catalyses the conversion of nitrobenzene and aniline to diphenylurea and CO2 the amine is used as the solvent.214 Ru3(C0)i2 catalyses the carbonylation of amines to formamides and the hydroamidation of olefins to carboxylic amides.215... 

Modest amounts, of formamides and/or ureas resulted from reaction of aliphatic and cycloalkyl nitro compounds with Fe(CO)s (Alper, 1972b). Photoreduction of aromatic nitro compounds to nitroso compounds or... 

The amino-substituted five-membered heterocycles are unstable compounds, but their acetyl and formyl derivatives can be isolated. N-(Selenienyl-3)formamide can be obtained via the reaction route shown in Scheme ll.134 An ortho, electron-attracting substituent, such as formyl or nitro, renders amino compounds stable. However, the yield of 2-nitro-3-aminoselenophene is quite low. 

Reductions with zinc are carried out in aqueous [160 as well as anhydrous solvents [163 and at different pHs of the medium. The choice of the reaction conditions is very important since entirely different results may be obtained under different conditions. While reduction of aromatic nitro groups in alkali hydroxides or aqueous ammonia gives hydrazo compounds, reduction in aqueous ammonium chloride gives hydroxylamines, and reduction in acidic medium amines (p. 73). Of organic solvents the most efficient seem to be dimethyl formamide [164 and acetic anhydride [755]. However, alcohols have... 

The reductive cyclization of 2-nitrobenzyl-A, A -bis(formamide) with zinc in acetic acid to quinazoline was first described by RiedelT ° The reaction is used successfully for the synthesis of larger quantities of quinazoline and its benzene-ring-substituted derivatives 12 from 2-ni-trobenzyl-A, A -bis(formamides) 11. The method is suitable only for the preparation of 4-un-substituted quinazolines, because 2-nitro-substituted phenones do not condense with aliphatic amides to yield bis(amide) derivatives. Zinc in acetic acid is the reducing agent of choice, but iron in hydrochloric acid or Raney nickel can also be used. " Applications of compounds other than bis(formamides) [e.g., bis(acetamides) ] and preparation of 2-substituted quinazolines by Riedel s synthesis are scarce. 

Fluorinated aromatic compounds. Finger and Kruse found that an aromatic chlorine or bromine atom activated by an o- or p-nitro group is subject to nucleophilic displacement by fluoride ipn on reaction with potassium fluoride in solvents such as succinonitrile, dimethyl formamide, or dimethyl sulfoxide. Unpublished work at Olin Mathieson Chemical Corporation indicates that best results are obtained with dimethyl sulfoxide as solvent and with potassium fluoride that has been finely ground (<100 mesh) and dried in a vacuum oven at 100° for at least 4 hrs. prior to use. In a typical case a mixture of p-nitrochlorobenzene, potassium fluoride, and dimethyl sulfoxide is stirred under reflux at 180° for 8-9 hrs., the cooled mixture... 

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