Aldehydes 2-aminobenzaldehyde

Virus replication comprises numerous biochemieal transformations that might provide suitable targets for antiviral therapy. The antiviral effect of thiosemicarbazones was first demonstrated by Hamre et al. [53, 54], who showed that p-aminobenzaldehyde-3-thiosemicarbazone and several of its derivatives were active against vaccinia virus in mice. These studies were extended to include thiosemicarbazones of isatin, benzene, thiophene, pyridine, and quinoline derivatives, which also showed activity against vaccinia-induced encephalitis. The nature of the aldehyde/ketone moiety was not as significant as the presence of the thiosemicarbazide side chain the latter was deemed essential for antiviral activity. 

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. 

This reaction is particularly useful in the Fricdlander quinoline synthesis, the use of which has been limited hy the inaccessibility of o-aminobenzaldehydes. Thus a one-pot synthesis of quinolines is now possible by reduction of an o-nitrobenz-aldehyde with the reagent in the presence of an a-mcthylene ketone. 

Polyaza rings suffer complete hydrolytic ring cleavage. Monocyclic 1,2,3-triazines are hydrolyzed by acid to yield 1,3-dicarbonyl compounds (Scheme 15). 1,2,3-Benzotriazines are easily converted into derivatives of 2-aminobenzaldehyde. 1,2,4,5-Tetrazines (180) are hydrolyzed with a base to give aldehyde hydrazones, RCH = NNHCOR. 

Reaction LIV. (c) Condensation of o-Aminobenzaldehydes with Aldehydes, Ketones, Ethyl acetoacetate, etc., under the influence of a trace of Sodium Hydroxide, to give Quinoline Derivatives (B., 16,1835 25,1752). —The first stage is the formation of an o-aminostyryl ketone. 

Nothing is known about analogous condensation reactions of o-alkyl-aminobenzaldehydes with a,/3-unsaturated cyclopentenones leading to pseudoazulenes 39, 43, or 46. Acid-catalyzed reaction of o-aminobenz-aldehyde with cyclopentenones produces 3//-cyclopenta[b] quinolines that can be transformed to 4H-cyclopenta[b]quinolines by quaternization and subsequent deprotonation.51... 

AMINOBENZ ALDEHYDE, 31,6 -Aminobenzaldehyde hydrazone, 31, 7 -Aminobenzaldehyde oxime, 31, 7 -Aminobenzaldehyde phenylhydra-zone, 31, 7... 

An aldehyde which carries substituents sensitive to alkali may undergo other changes involving these groups. An example is found in o-acetyl-aminobenzaldehyde, which undergoes an intramolecular condensation leading to 2-hydroxyquinoline.72... 

Dinitro 4-aminobenzaldehyde. Yel crysts (from ale), mp 171 easily sol in chlf, bz, AcOH and et acet diff sol in eth and pet eth. Can be prepd by treating 3,5 dinitroanis. aldehyde with alcoholic NH, or by nitrating (4-aminobenzal)aniline with mixed HNO,-HjSO at not higher than 5-6 . Its expl... 

Quadridentate ligands can be obtained by condensing suitably substituted aldehydes and ketones with bidentate primary amines, and the resulting Schiff bases closely resemble the porphin ring system. Generally, one of the structural units—N=C—C=N—,—N=C—NHC=N—, N=C—NH—N=C—, —C=N—CH=CH—N=C—, or —C=N— CH2—CH2—N=C—is incorporated into the structure for maximum stability. For example, if or /io-aminobenzaldehyde is condensed with ortho-... 

Vilsmeier and Haack found that the reagent forms a 1 1 complex with phosphoryl chloride and that this attacks an aromatic compound of adequate reactivity to give a product hydrolyzed by water to an aromatic aldehyde. They prepared p-dimethyl-aminobenzaldehyde, but did not record full details ... 

A general synthesis of quinazoline 1,3-dioxides and their 1,2-dihydro derivatives was devised by Taylor and Bartulin. In this synthesis o-hydroxyl-aminobenzaldehyde oxime condensed with aldehydes and ketones to yield 2,2-disubstituted 1,2-dihydro-l-hydroxyquinazoline 3-oxides (63). When the dihydro compounds (63 = H) derived from aldehydes or from formalde-... 

Heating the aminoacetal (2.1) with ethanolic hydrogen chloride produces a quinoline [2612], but sulphuric acid causes the cyclization to follow another course (see Chapter 3, Section II. 1). n-Aminoaldehydes are cyclized by heating with a reactive methylene-containing ketone, ester or nitrile but in the reaction with the pyrazole aldehyde (2.2), yields seem to depend greatly on the nature of the A -substituent for example, when R = R = CN, the product is obtained in either 3.6% or 83% yields according to whether R is methyl or phenyl [2798]. The chemistry of a-cyanothioacetamide (2.4), which is used in the conversion of 2-aminobenzaldehyde (2.3) to 2-aminoquinoline-3-thiocarboxamide [2926], has been reviewed [3331]. 

Deduce structures for the heterocyclic products from the following combinations (i) C11H7N3O2 from 2-aminobenzaldehyde and barbituric acid (ii) CmHuNOs from 4,5-methylenedioxy-2-aminobenzaldehyde and dimethyl acetylenedicarboxylate (iii) CmHuNS from 2-aminoacetophenone and 2-acetylthiophen (iv) C21H19NO from 2-aminobenzophenone and dimedone (v) C15H12N2O2S from 2-aminopyridine-3-aldehyde and 1-phenylsulfonylacetone (vi) C15HHN3 from 4-amino-pyrimidine-5-aldehyde and a-tetralone. 

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