M Nitrobenzaldehyde

Potassium and sodium borohydride show greater selectivity in action than lithium aluminium hydride thus ketones or aldehydes may be reduced to alcohols whilst the cyano, nitro, amido and carbalkoxy groups remain unaffected. Furthermore, the reagent may be used in aqueous or aqueous-alcoholic solution. One simple application of its use will be described, viz., the reduction of m-nitrobenzaldehyde to m-nitrobenzyl alcohol ... 

Kinetic investigation of the reaction of cotarnine and a few aromatic aldehydes (iV-methylcotarnine, m-nitrobenzaldehyde) with hydrogen eyanide in anhydrous tetrahydrofuran showed such differences in the kinetic and thermodynamic parameters for cotarnine compared to those for the aldehydes, and also in the effect of catalysts, so that the possibility that cotarnine was reacting in the hypothetical amino-aldehyde form could be completely eliminated. Even if the amino-aldehyde form is present in concentrations under the limit of spectroscopic detection, then it still certainly plays no pfi,rt in the chemical reactions. This is also expected by Kabachnik s conclusions for the reactions of tautomeric systems where the equilibrium is very predominantly on one side. 

A useful reaction sequence has been developed for conversion of an aromatic aldehyde into the next higher homologous acid. The nitro analog of 45, prepared from m-nitrobenzaldehyde, is converted into the azide 51 by hydrazinolysis and treatment with nitrous acid. The... 

A Preparation of a-Ethyl-m-Nitrocinnamic Acid This acid is prepared from 100 g of m-nitrobenzaldehyde, 210 g of butyric anhydride and 73 g of sodium butyrate. The crude a-ethyl-m-nitrocinnamic acid is crystallized from ethanol giving about 105 g, MP 140° to 142°C. From the filtrates there may be isolated a small amount of a stereoisomer, which when pure melts at 105° to 106°C. 

Acetoacetic acid N-benzyl-N-methyiaminoethyl ester -Aminocrotonic acid methyl ester m-Nitrobenzaldehyde... 

A mixture of 4.98 g of acetoacetic acid N-benzyl-N-methylaminoethyl ester, 2.3 g of aminocrotonic acid methyl ester, and 3 g of m-nitrobenzaldehyde was stirred for 6 hours at 100°C in an oil bath. The reaction mixture was subjected to a silica gel column chromatography (diameter 4 cm and height 25 cm) and then eluted with a 20 1 mixture of chloroform and acetone. The effluent containing the subject product was concentrated and checked by thin layer chromatography. The powdery product thus obtained was dissolved in acetone and after adjusting the solution with an ethanol solution saturated with hydrogen chloride to pH 1 -2, the solution was concentrated to provide 2 g of 2,6-dimethyl-4-(3 -nitrophenyl)-1,4-dihydropyridlne-3,5-dicarboxylic acid 3-methylester-5- -(N-benzyl-N-methylamino)ethyl ester hydrochloride. The product thus obtained was then crystallized from an acetone mixture, melting point 136°Cto 140°C (decomposed). 

The oxidations of formic acid by Co(III) and V(V) are straightforward, being first-order with respect to both oxidant and substrate and acid-inverse and slightly acid-catalysed respectively. The primary kinetic isotope effects are l.Sj (25°C)forCo(IU)and4.1 (61.5 C°)for V(V). The low value for Co(lII) is analogous to those for Co(IIl) oxidations of secondary alcohols, formaldehyde and m-nitrobenzaldehyde vide supra). A djo/ h20 for the Co(III) oxidation is about 1.0, which is curiously high for an acid-inverse reaction . The mechanisms clearly parallel those for oxidation of alcohols (p. 376) where Rj and R2 become doubly bonded oxygen. 

This new type of photoredox reaction of p- and m-nitro-substitutcd aromatic derivatives is not observed in organic solvents, and is99,100 extended to m-nitrobenzyl derivatives 162 containing alcohol, alkyl ether, ester or amine functions these compounds undergo photooxidation to produce m-nitrobenzaldehyde (or m-nitroacetophenone) as the major isolable product100 (equation 79). 

A rapidly stirred mixture of 10 gm (0.185 mole) of potassium borohydride and 250 ml of ethanol containing a small amount of potassium hydroxide is heated to the reflux temperature. Then a solution of 5.0 gm (0.033 mole) of m-nitrobenzaldehyde in a small amount of ethanol is added and heating is continued for 24 hr. After this period, half of the solvent is removed by distillation under reduced pressure. The residue is cooled and added, with stirring, to a mixture of ice and concentrated hydrochloric acid. The crude product is collected on a filter, washed free of excess acid with water, and dried. The product is ultimately recrystallized. Yield 4.3 gm (71 %), m.p. 82°-83°C. 

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