Of 4-nitrobenzaldehyde

Zinc-mediated benzylation of carbonyl compounds in aqueous media was reported by Bieber.214 The benzylation of 4-nitrobenzaldehyde... 

The photochemistry of 4-nitrobenzaldehyde has been reinvestigated In aqueous solution, 4-nitrosobenzoic acid is formed. A ketene has been proposed as intermediate... 

Experiments in deoxygenated ethanol solution in the dark showed that, by stirring, 4-nitrobenz-aldehyde is obtained in 60% yield, accompanied by 13% 2-(4-nitrobenzyl)-2-nitropropane. Under the same conditions, but with sonication, the yields are 23% of 4-nitrobenzaldehyde and 48% of 2-(4-nitrobenzyl)-2-nitropropane (Einhorn et al. 1990). The importance of this result consists in the following conclusion The ultrasonic irradiation has a marked influence on the relative rates of the competing reactions and stimnlates just the ion-radical one. 

Kohler et al. (4) extruder processed polyphenylenesulfide containing the bisazo-methine of 4-nitrobenzaldehyde and bis-(4-aminophenyl)methane with 40 wt% glass fibers and the product used molding compositions. 

A powerful solvent effect occurs in the reaction of 4-nitrobenzaldehyde with sulfur tetrafluoride. The reaction conducted in a benzene solution gives the expected l-(difluoromethyl)-4-nitro-benzene (16), while without a solvent bis[fluoro(4-nitrophenyl)methyl] ether (17) is formed as the sole product and in high yield.79 Other benzaldehydcs do not give a-fluoro ethers under any conditions, probably because of instability of such ethers under acid conditions.79... 

Direct inspection (by NMR) of mixtures of 4-nitrobenzaldehyde, or pyridine-4-carbaldehyde, in hexadeutero DMSO and piperidine reveals the presence of 140 in the... 

S)-Proline also catalyzed the Mannich-type reactions of unmodified aldehydes and N-PMP-protected imines to afford the corresponding enantiomerically enriched / -aminoaldehydes at 4 °C (Table 2.13) [71b]. The products were isolated after reduction with NaBH4, though oxidation to the / -amino acid is also possible. These reactions also provided the syn-isomer as the major diastereomer with high enantioselectivities, and proceeded well in other solvents (e.g., dioxane, THF, Et20). In the reaction of propionaldehyde and the N-PMP-imine of 4-nitrobenzaldehyde in DMF, the addition of water (up to 20%, v/v) did not affect the enantioselectivity. Similar results were obtained for the (S)-proline-catalyzed Mannich-type reactions with the glyoxylate imine where water did not reduce enantioselectivity [71b]. However, the enantioselectivity of the reaction of propionaldehyde and the N-PMP-imine of benzaldehyde in DMF was decreased by the addition of water or MeOH [71b]. 

The title compound, 319, has been prepared311 in three steps starting with nucleophilic displacement of the nitro group of 4-nitrobenzaldehyde 321 with [18F]CsF, followed by reduction of the [18F]4-fluorobenzaldehyde 322 with LiAlH4 and treatment of crude alcohol with 47% HI. 320 has been obtained in the reaction of 319 with spiperone (equation 138). 

Various bases can be used as the catalyst instead of the fluoride ion. Thus, the reaction of 4-nitrobenzaldehyde with trimethyl(perfluoro-6-chlorohexyl)silane (16) occurs in the presence of methoxide. " ... 

Olefination of aromatic and aliphatic aldehydes was achieved using either P4-t-Bu or KOH-TBAB as the base. Aromatic aldehydes gave the products in which the E isomer is dominant, with the exception of 4-nitrobenzaldehyde— P4-t-Bu (Table 18, entry 5). In reaction with cyclohexanecarboxaldehyde, stereoselectivity was lower and the Z-isomer was obtained as the major product. 

However, in reactions of sulfones equipped with anion-stabiUzing groups, the addition step may be reversible. For example, hydroxysulfone 262 (Scheme 84, prepared from trans stilbene oxide and 2-mercapto-benzothia-zole) when treated with LDA in the presence of 4-nitrobenzaldehyde, afforded styrene 263 and nitrostyrene 264. Consequently, the stereochemical outcome of the reaction is decided in the following steps. 

By contrast if (40a) is reacted with trifiuoroacetic anhydride (TFAA) at low temperatures and the reaction then allowed to warm, the (Z)-alkene is obtained, presumably by a cyclic ester Q pe elimination (Scheme 6). The isolated yields (72-77%) of (Z)-alkene are rather lower than the yields for the ( )-al-kene process, as are the stereoselectivities. In Ae case of 4-nitrobenzaldehyde the process shows little stereoselectivity. ... 

As a test reaction to determine the activity of this catalyst, the coupling of 4-nitrobenzaldehyde with methyl vinyl ketone, a paradigmatic example of the Baylis-Hillman reaction, was selected. The major product was the corresponding p-hydroxyketone 110 accompanied by minor amounts of the Michael adduct 111 that appeared at high conversions when an excess of methyl vinyl ketone was utilized (Scheme 3.31). 

A mixture of products was produced in the case of 4-nitrobenzaldehyde due to competing reduction of the nitro group as observed by the reduction of nitrobenzene in an independent experiment and also with aliphatic aldehydes. No coupling of 4-chlorobenzaldehyde took place when methanol was replaced by THF, but when methanol was replaced by MeCN, a mixture of containing starting aldehyde, the corresponding alcohol and the diol was obtained. 

Nitrofurazone was one of the first furan derivatives to be useful as a chemotherapeutic agent. The semicarbazones of 4-nitrobenzaldehyde, 5-nitro-thiophenaldehyde, and of 5-nitropyrrolaldehyde were less effective and not suitable for clinical use . Antibacterial activity is conferred on non-nitrated furans if a nitro group is introduced in the 5-position of the furan ring. Later this was recognized to be an indispensable prerequisite. Microbiologists of the Norwich Pharmacal Co. have summarized the activity against representative species of bacteria (Table 6.22). The six tested nitrofurans, however. 

A comprehensive study of the solvent dependence of the photophysical properties of 9,9 -bianthryl shows that the fluorescence lifetime is essentially constant in low polarity solvents. In more polar solvents, light-induced electron transfer occurs to form a perpendicular ICT state having D2d symmetry and which is weakly fluorescent. Reports have appeared that describe the photoisomerization of 4-nitrobenzaldehyde, 5-hydroxytropolone, 4-hydroxybenzonitrile, methyl-benzonitrile, and cinnamaldehyde. ... 

Nanosecond laser photolysis and conductimetric detection have been used to show that the photoisomerisation of 4-nitrobenzaldehyde to 4-nitrosobenzoic acid in aqueous solution occurs via the mechanism in Scheme 4 The... 

Asymmetric aldol reaction of 4-nitrobenzaldehyde with cyclohexanone. 

Table 2.32 Aldol Reaction of 4-Nitrobenzaldehyde With Cyclohexanone ...

Zhao el al. have developed an efficient and recyclable hairy particle-sup-ported 4-A,A-dialkylaminopyridine (DAAP) catalyst (393), which is efficient in eatalyzing the MBH reaction of 4-nitrobenzaldehyde and methyl vinyl ketone... 

ProUnamide-catalyzed aldol reactions of 4-nitrobenzaldehyde (2a) with... 

Nitroaldol reaction of 4-nitrobenzaldehyde with 2-nitropropane in the presence of triethylamine combined with lipase-catalysed acylation afforded corresponding... 

Chromyl chloride and esters are not usual oxidants. A new preparation of these potentially useful reagents has been foimd using sonochemical mediods. An illustration of their synthetic potential is given with the preparation of 4-nitrobenzaldehyde. 

The aldol reaction (aldol condensation) is one of the fundamental reactions of organic chemistry because it leads to the formation of a new carbon-carbon bond (see Experiment [20] for a very similar example of the Qaisen-Schmidt type of aldol reaction). In this version, the condensation of 4-nitrobenzaldehyde (an aldehyde without an a-hydrogen atom) with acetophenone (a ketone) gives frans-4-nitrochalcone.The aldol condensation of the unsubstituted aromatic aldehyde, benzaldehyde with acetophenone, yields frans-l,3-diphenyl-2-propenone (PhCH CHCOPh), which has the common name, chalcone.Thus, the substituted derivatives of this system are known collectively as chalcones. 

Reagents and Equipment. Weigh and place 500 mg (3.31 mmol) of 4-nitrobenzaldehyde in a 50-mL Erlenmeyer flask containing a magnetic stir bar. Now add 20 mL of 95% ethanol and 488 gL of acetophenone. 

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