Benzaldehyde, o-nitro

Nitro compounds have also been reported to undergo photocyclizations. The intermediacy of an isoxazoline in the photorearrangement of o-nitro-benzaldehyde to o-nitrosobenzoic acid is now in doubt,318 but intramolecular hydrogen abstraction by an excited nitro group in nitrobenzene derivatives can result in the formation of heterocycles. 4-tm-Butyl-3-methoxy-2,6-dinitrotoluene (384) on irradiation in methanolic sodium hydroxide solution... 

For the reduction of nitro-compounds containing a group which may be attacked by nascent hydrogen, as, for example, an aldehyde group, an unsaturated side chain, and so on, special methods must he applied. In such cases ferrous hydroxide or iron powder (cf. Chap. VII. 5, arsanilic acid) are often used. The reduction is carried out thus a weighed amount of ferrous sulphate is caused to act, in the presence of alkali (potassium or sodium hydroxide, baryta), on the substance to he reduced. In this way it is possible to reduce, for example, o-nitro-benzaldehyde to aminobenzaldehyde, and o-nitrocinnamic acid to amino-cinnamic acid. 

Very pure material can be obtained by dissolving o-nitro-benzaldehyde in toluene and precipitating with petroleum ether, according to earlier instructions.3... 

Because the phosphonate-phosphate rearrangement requires P-C bond breakage and formation of the P-O bond kinetic isotope studies by means of 13C NMR were chosen.50 13C KIEs were derived from NMR analysis of substrate-o-nitro-benzaldehyde or product-phosphate. Samples of aldehyde were prepared using the dead-end method. To the solution of phosphite 3 and triethylamine in acetonitrile an excess of aldehyde was added and solution was heated at 65°C to complete conversion of phosphonate 4 to phosphate 5 monitored by 31P NMR. The aldehyde conversions 0.2-0.8 were calculated from the balance of concentrations. The changes of 13C composition were determined for carbonyl carbon atom using signal of meta aryl carbon as an internal standard. KIE 1.0223(14) was calculated from the slope of linear relationship of isotopic ratio R and fraction of reaction,... 

The reduction is effected by adding to the substance to be reduced, in tire presence of an alkali (potassium-, sodium-, or barium-hydroxide), a weighed quantity of ferrous sulphate. By this reaction, o-nitro-benzaldehyde is reduced to o-amidobenzaldehyde o-nitrocinnamic acid to o-amidocinnainic acid. 

Baeyer-Drewson indigo synthesis. Formation of indigos by an aldol addition of o-nitrobenzal-dehydes to acetone, pymvic acid, or acetaldehyde. Of interest mainly as a method of protecting o-nitro-benzaldehydes. 

Once we determined the best reaction conditions, the scope was explored. Products I-16a-h of [2-I-2-I-2] cycloaddition were isolated from enyne I-15a in 21-85 % yield, along with 1,3-dienes I-17a-h (Table 2.4). The reaction proceeded readily with electron-rich aldehydes. Conversely, in the reaction of I-15a with o-nitro-benzaldehyde, no adduct was formed (Table 2.4, entry 17), which is in contrast with the previously reported results for 1,6-enynes bearing a terminal aUcene moiety 1-9 [Refs. 226, 228 in Chap. 1]. 

The structural volume changes photoinduced in solution during the proton transfer between o-nitro-benzaldehyde and hydroxyls in water have been recently studied by means of LIOAS. Upon photoexcitation, o-nitrobenzaldehyde is converted to o-nitro-... 

Benzaldehyde, o nitro, 46,81 Benzaldehyde, 2,4,6-trimethyl-, 47,1 Benzaldehydes, halogen- and methyl-substituted, preparation from diazomum salts and formal doxime, 46, IS... 

Slightly greater effects are observed for the B-bands of m-hydroxy-benzaldehyde and ra-nitrophenol (D, H-bond +68 and +96 A), although the nitro and formyl groups may not be terminal. Greater displacements should have been expected for the B-bands of o-hydroxy benzaldehyde and o-nitrophenol, but, owing to the formation of intramolecular hydrogen bonds by these derivatives (cf. below), an experimental confirmation is, unfortunately, not possible. 

The method is of great value in dealing with substances which are sensitive to strong acids or bases, such as o-nitro- and amino-benzaldehydes, nitro- and amino-benzamides and benzoylureas, and is also of service in the preparation of other ammo acids. 

The complexes ML2, where M = Co, Cu, Ni, Zn HL = 2-hydroxy-5-(chloro/ nitro)-benzaldehyde[4-(3-methyl-3-mesitylcyclobutyl)-l,3-thiazol-2-yl]hydra-zone, give IR spectra indicating chelation of L through azomethine N and phenolate O atoms.509 Coordination of the 5-(2 -carboxyphenylazo)-8-hydro-xyquinoline to Co, Ni, Cu or U022+ via CN, N=N, COOH and OH was shown by IR spectroscopy.510 IR data for M(II) (=Co, Ni, Cu, Zn) complexes of A -salicyloyl-A"-/)-hydroxythiobenzohydrazide and related ligands show coordination by thiolato S, enolic O and two hydrazine N atoms.511... 

AI3-02415 Benzaldehyde, 2-nitra- Benzaldehyde, o-nitro- CCRIS 2322 EINECS 209-025-3 2-Nitro-benzaldehyde 0-Nitrobenzaldehyde NSC 5713. Used in the synthesis of dyes, pharmaceuticals, surface active agents. Yellow needles mp = 43.5° bp23 = 153" d = 1.1111 Xm = 252 nm ( - 4400, MeOH) slightly soluble in H2O, CHCI3, very soluble in EtOH, Et20, Me2CO, CeHe. Lancaster Synthesis Co. Penta Mfg. 

Nitro-benzaldehyde sind bereits mit relativ schwachen Basen alkylidenylierbar (s.o.). Weitere Beispiele zeigt Tab. 71 (S. 418). Lactole aromatischer Aldehydsauren reagieren un-ter Ringoffnung z.B.823 ... 

Nitro-benzaldehyd kondensiert in Gegenwart von Piperidin mit l-Thiomalonsaure-3-O-ethylester-1 -O-isopropylester zu (4-Nitro-benzyliden)-l-thiomalonsaure-3-ethylester-l-0-isopropylester (85%)66,vs,a-67. Audi iiber die Michael-Additionen CH-adder Thiocarbonsaure-O-ester an Acrylnitril oder Acrylsaureester werden neue Thiocarbonsaure-O-ester zuganglich65,66 ... 

Benzaldehyde, nt-HYDROXY-, 26, 55 Benzaldehyde, > -methoxy-, 29, 63 Benzaldehyde, o-nitro-, 24, 75 Benzaldehyde, tiMiasiO-, dihetbyi acetal, 29, 72... 

Although acridone was not first synthesized by Lehmstedt, it was Lehmstedt who extensively explored the methods for the preparation of acridones, including the reaction between anthranilic acid and chloro-nitrobenzene, desulfurization of thioacridone by copper, and treatment of ortho-nitro benzaldehyde with chloro-nitrobenzene and sulfuric acid. Among these methods, the one between o-nitrobenzaldehyde and halobenzene is known as the Lehmstedt-Tanasescu method or Lehmstedt-Tanasescu reaction. In addition, this preparation of acridone is also referred to as the Tanasescu synthesis. ... 

Reductions of aromatic nitro compounds provide a simple and general access to various heterocyclic compounds through the domino process (Scheme 9.23). Quinolines are important skeletal moieties present in various natural products and biologically active compounds [58]. Most common methods of their preparation involve condensation of o-amino benzaldehydes with an enolizable carbonyl compound (Friedlander synthesis) [59]. Miller et al. [60] reported an efficient synthesis of quinolines 109, in which a reduction of o-nitroaryl carbaldehyde by SnCl2 followed by condensation with an enolizable carbonyl compound in the presence of ZnCl2 yielded 109 through a domino process. In 2001, Bunce et al. [61] reported a domino nitroarene reduction/reductive amination sequence for the preparation of tetrahydroquinoline-4-carboxylic ester 110 with excellent yields. 

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