Amino Aminobenzaldehyde

The alkaloid vasicine was first isolated from Adhatoda vasica in 1925 but the structure (996) was elucidated only after a great amount of work, culminating in two independent syntheses in 1935 (B-53MI21301). It was made subsequently by a simple route from 2-aminobenzaldehyde and 4-amino-2-hydroxybutyraldehyde (994) followed by dehydration of the tricyclic intermediate (995) (60TL(25)44>. Vasicine has bronchodilatory activity of a low order. Two related unnamed alkaloids (997) and (998) were obtained in 1965 from members of the Araliaceae family, viz. Mackinlaya subulata and M. macrosciadia both had been synthesized earlier (66AJC151). 

Amidation, of thiocyanic acid with o-chloroaniline, 31, 21 Amino acid, 30, 7 -Ahinobenzaldehyde, 31, 6 -Aminobenzaldehyde hydrazone, 31, 7 / -Aminobenzaldehyde oxime, 31, 7 -Aminobenzaldehyde phenylhydra-zone, 31, 7... 

Azoic coupling can be achieved on silk where free amino groups have been introduced into the fibroin structure by condensation with 4-aminobenzaldehyde. The diazotised material can then be treated with an azoic coupling component [109]. 

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. 

Similar reducing effects are obtained from alkali sulfides, hydrosulfides and polysulfides [241]. A peculiar reaction believed to be due to sodium polysulfide formed in situ by refluxing sulfur in aqueous-ethanolic sodium hydroxide is a conversion of p-nitrotoluene to p-aminobenzaldehyde [242]. Oxidation of the methyl group by the polysulfide generates hydrogen sulfide which then reduces the nitro group to the amino group. 

Hantzsch-type reaction between 5-amino-3-methyl-l-phenylpyrazole, 4-dimethyl-aminobenzaldehyde, and 2-aroylbenzimidazole is followed by elimination of 4-dimethylaminophelyl substituent [75]. The treatments that were carried out in boiling glacial acetic acids for 2 h yielded pyrazolopyridines 44 when Ry 4-NO2C6H4 (Scheme 19). 

Aminoquinazolines can be prepared by the reaction of guanidine with 2-aminobenzaldehydes, although yields are only moderate, as shown by the synthesis of 2-amino-5-bromoquinazoline 841 which occurred in only an 18% yield <2003JA2084>. 

Test for indole Indole is a component of the amino acid tryptophan, which can he broken down by the bacterial enzyme tryptophanase. When tryptophan is broken down, the presence of indole can be detected through the use of Kovacs reagent. Kovacs reagent, which is yellow, reacts with indole and produces a red colour on the surface of the test tube. Kovacs reagent is prepared by dissolving 10 g of p-aminobenzaldehyde in 150 mL of isoamylalcohol and then slowly adding 50 mL of concentrated HCl. 

Amide reduction with lithium aluminum hydride, 39, 19 Amine oxide formation, 39, 40 Amine oxide pyrolysis, 39, 41, 42 -Aminoacetanilide, 39, 1 Amino adds, synthesis of, 30, 7 2-Amino-4-anilino-6-(chloro-METHYl) -S-TRIAZINE, 38, 1 -Aminobenzaldehyde, 31, 6 hydrazone, 31, 7 oxime, 31, 7 phenylhydrazone, 31, 7 > -Aminobenzoic add, 36, 95 2-Aminobenzophenone, 32, 8 c-Aminocaproic acid, 32, 13 6-Aminocaproic acid hydrochloride,... 

The self-condensation of 2-aminobenzaldehyde in the presence of suitable metal ions to form the cyclic tetramer (1), and sometimes the trimer (2), is the best-known example of this reaction type (Scheme 2). The cyclization of the / -amino ketone complex (5) provides an aliphatic example... 

Complexes of nickel(II), copper(II), cobalt(III), zinc(II), iron(II), palladium(II), platj-num(II) and vanadyl can be obtained. Although the reaction sequence is fairly general for metal ions, it is not easily extendable to substituted 2-aminobenzaldehydes. However, 2-amino-5-me-thylbenzaldehyde has recently been used successfully in the macrocyclization reaction.147... 

Tri- and Tetra-Substituted Benzaldehydes. No important deviation from the limitations discussed above are to be noted when further substituents are present, provided that at least one position ortho to the formyl group is open. When an ortho or para hydroxyl group is present neither dismutation nor cleavage occurs under the usual conditions of the reaction. An ortho-amino group acts similarly 2,5-dichloro-6-aminobenzaldehyde was recovered after treatment with 50% KOH at 100° for four hours.78 0... 

The ligands NiV -bis-(2-aminoacetophenone)ettiylenediamine, NN -bis-(2-amino-benzophenone)ethylenediamine, and AiV -bis-(2-aminobenzaldehyde)ethylene-diamine (LH2) form mononuclear (CoLX) complexes and the more unusual bi- and tri-metallic derivatives (56) and (57).342... 

The 6-amino 88 (58%) and 6-hydroxy 90 (84%) derivatives were synthesized by the cyclization of imine 87 and ketone 89, respectively (79JHC753). 1,3-Disubstituted derivatives 92 were prepared by the reaction of pyrylium salts 91 with o-aminobenzaldehyde (71% for 92 R = Me) (71TL553). 

Other functional groups may be present during reduction. Aromatic amino ethers are prepared by the same general procedures described above, e.g., 772-aminoanisole (80%) and 2-aminodiphenyl ether (94%). The reduction of o-nitrobenzaldehyde to the sensitive o-aminobenzaldehyde is successfully accomplished by the action of ferrous sulfate and ammonia (75%). m-Dimethylaminobenzaldehyde is formed by reduction of the nitro acetal in aqueous solution with sodium sulfide followed by methyla-tion (74% over-all) or by catalytic reduction of m-nitrobenzaldehyde in... 

Amino-5-deoxy-D-xylopyranose (17) has the structure of a cyclic a-amino alcohol and should, accordingly, react with nucleophiles, leading to a-amino alkylation. " These reactions generally proceed under acid catalysis, and are only applicable to 17 if they provide rapid formation of stable products otherwise, rearrangement to 22 results. The condensation of 17 with o-aminobenzaldehyde at pH 5 gives the quinazolinium derivative (36), isolated as a red, crystalline picrate. This reaction serves as a specific chromatographic indicator for 16 17. 

Condensation of 2-amino-N-phenacylpyridinium bromide (280) with p-dimethyl-aminobenzaldehyde (281) (76lJC(B)55i) and that of 2-acetoacetylaminopyridine (283) with... 

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