T»-Nitrobenzaldehyde

Scheme 6 Two routes for the synthesis of photodegradable polymers using T-nitrobenzaldehyde...

Oxaziridine formation by photoisomerization of nitrones was discovered almost simultaneously with the peracid procedure (58JOC65l>. The t-butyl nitrones of benzaldehyde and 4-nitrobenzaldehyde yielded about 90% of oxaziridines (254) and (255) on UV irradiation. 

Acetoxy-3-methoxybenzaldehyde, 3290 4-Acetoxy-3-methoxy-2-nitrobenzaldehyde, 3266 t Acrylaldehyde, 1145... 

Azidobenzaldehyde, 2697 t Benzaldehyde, 2731 t Butyraldehyde, 1607 Chloroacetaldehyde oxime, 0787 2-Chloro-6-nitrobenzaldehyde, 2650... 

The reaction of barbiturate and 1,3 -dimethylbarbiturate ions with 2- and 4-nitrobenzaldehyde and 2,4-dinitrobenzaldehyde represented generally in Scheme 5 involves a diffusion-controlled (viscosity effects on rates) proton transfer from hydronium ion to an addition intermediate T in the slow step.14 The addition of water and ring-opening reactions of the protonated benzoxazines (14) involves the cyclic intermediate (15). At low buffer concentrations buffer-catalysed collapse of the intermediate is rate limiting but, at high buffer concentrations, the addition of water is the rate-limiting step.15 The anionic tetrahedral intermediate (16) is involved in the hydrolysis of the 2, 2, 2,-trifluoroethyl monoester of 1,8-naphthalic acid (17).16... 

The starting aldehyde H signal (S = 10.36) was shifted to S = 5.33 as required for a change of sp2 to sp3 hybridization by passing from 4-nitrobenzaldehyde to derivative 140 (equation 27). Similar behaviour was observed for mixtures of aromatic aldehydes and of some primary amines (butylamine, t-butylamine) the presence of the 1,1-aminoalcohol (141) was observed for short times, after the imine (142)215 had been formed (equation 28). 

Chloromethylphenyl acetate, (4-Acetoxyphenyl)methyl chloride, see 4-Acetoxybenzyl chloride, 3132b 2-Chloro-5-methylphenylhydroxylamine, 2792 Chloromethylphenylsilane, 2806 f 3-Chloro-2-methyl-l-propene, 1548 2-Chloromethylthiophene, 1836 A-Chloro-3-morpholinone, 1485 /V- C h I o ro -4 - n i t ro a n i I i n e, 2224 2-Chloro-5-nitrobenzaldehyde, 2645 2-Chloro-6-nitrobenzaldehyde, 2646... 

The synthesis of ( )-7-ACA 81a is shown in Scheme 19. Reaction of 77 with 4-nitrobenzaldehyde followed by treatment with Hilnig s base gave a 2 3 mixture of cis/trans isomers of the Schiff base 79. Compound 79 was therefore cleaved with Girard s reagent T and amines 77 and 80 were obtained after chromatography. Amine 80 was converted to ( )-7-ACA 81a as outlined below. 

We have also examined the use of cyclodextrin-derived artificial enzymes in promoting bimolecular aldol reactions, specifically those of m-nitrobenzaldehyde (57) and ofp-t-butylbenzaldehyde (58) with acetone [141]. Here, we examined a group of mono-substituted cyclodextrins as catalysts (e.g. 59), as well as two disubstituted (3-cyclodextrins (e.g. 60) (10 catalysts in all). They all bound the aldehyde components in the cyclodextrin cavity and used amino groups of the substituents to convert the acetone into its enamine. An intracomplex reaction with 58 and hydrolysis of the enamine product then afforded hydroxyketone 61 (cf. 62). These catalysts imitate natural enzymes classified as Class I aldolases. 

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. 

Cyclohexanecarbaldehyde 4-Nitrobenzaldehyde 4-r-Butylcyclohexanone PhTi(OPr )3 HiTi(OPr )3 PhTi(OPr )3 THF Et20 Et20 1.0 0.5 15.0 -10 -15 r.t. Cyclohexylf nylmethanol (4-Nittophenyl)phenylniethanol 1 -Hienyf-4+-butylcyclohexanol 84 (95) 94 95 a ... 

Ogawa, H., Hosoe, T., Senda, H. Na-zeolites promoted Cannizzaro reaction of p-nitrobenzaldehyde in liquid phase. Tokyo Gakugei Daigaku Kiyo, Dai-4-bumon Sugaku, Shizen Kagaku 2003, 55, 35-38. 

Separation of aldehydes.2 o-Nitrobenzaldehyde (302 mg) and reagent T (502 mg) was stirred in EtOH (5 mL) under reflux. After cooling the water sofabte hycrazone 2 (406 mg), mp 229-230°C was obtained. Add hydrolysis gave back the aldehyde. 

In the 2010s, Aitken et al. demonstrated that a solvent-free organocata-lysed aldol reaction could be achieved by addition of 2-hydroigr-cyclobutanone 11 n = 1) to 4-nitrobenzaldehyde in the presence of L-threonine (Scheme 12.4). The temperature played an important role in the stereochemical outcome, as the -adduct 12 was obtained at low temperature, whereas the same reaction performed at 25 °C and/or in wet DMF led mainly to the a t/-adduct regardless of the amino acid structure. 

Thus, reactions which need only local translation or rotation of reactants are supposed to proceed even below T for example, photochemical chain scission of polymaic ketones by Hartley and Guillet photochromic reacticms of spirobenzopyran by Gardlund photoisomerization of azocompounds by Kamogawa et al. and photorearrangement of o-nitrobenzaldehyde by C owell and Pitts Following those... 

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