Dimethyl aminobenzaldehyde

It is found in civet and in the wood of Celtis reticulosa. It forms crystals melting at 95° and boiling at 265° to 266°. It yields a hydrochloride, 2(C9HgN). HCl, melting at 167° 10 168°, and a picric acid compound melting at 172° to 173°. Skatol yields a blue colour with a solution of dimethyl-aminobenzaldehyde. 

High performance liquid chromatography is used to determine the purity of calcitriol, and to separate it from related compounds. Using a 10 micron silica column of 25 cm length, and a mobile phase of spectroquality heptane ethyl acetate. methanol (50 50 1) at a flow rate of 1.7 ml/ minute, separation and quantitation are achieved. p-Dimethyl-aminobenzaldehyde may be used as an internal standard to compensate for variations in injection technique and instrumental conditions. With a 254 nm ultraviolet absorbance detector, 0.01 ug of calcitriol may be detected (3). 

Collagen determination. In order to calculate the amount of collagen in a sample, hydroxyproline was measured in acid hydrolyzates (Jamall et al., 1981). After oxidation, hydroxyproline reacts with p-dimethyl-aminobenzaldehyde to give a red colour, which is measured by spectrophotometry. For bovine dentin, collagen mass was estimated as 8.0 x the hydroxyproline value as calculated from previous data (Volpin and Veis, 1973). To calculate the molar quantities of collagen, a molecular mass of 300 kDa was used. 

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). 

Hydrazine solutions may be analyzed by various colorimetric methods. Low concentrations of hydrazine in aqueous samples at ppm level may be determined by treating the sample with an acidified solution of dimethyl-aminobenzaldehyde and the absorbance of color formed is measured at 485 nm with a spectrophotometer. 

Methyl groups a or y to the cationic nitrogen are active towards condensation as illustrated (Scheme 120) by the reaction of 2,4-dimethyl-l-azaquinoIizinium ion with p-dimethyl-aminobenzaldehyde (72UKZ262). 

The reaction product of dimethyl malonate and 1,6-hexanediol with dimethyl-aminobenzaldehyde, 4-methoxy-benzaldehyde, and 3-nitrobenzaldehyde was previously prepared by the authors (2) and used in ophthalmic applications. 

SFE, Supercritical-fluid extraction MSTFA, N-methyl-N-(trimethylsily)trifluoro-acetamide OPA, o-phthalaldehyde DMBA, p-dimethyl-aminobenzaldehyde. 

The pyridine used must be free of pyrrole since as little as 0.001% of pyrrole will markedly decrease the yield. The checkers found it most satisfactory to use spectroquality pyridine supplied by Matheson, Coleman and Bell. The submitters purified their pyridine by distillation from potassium hydroxide. To test for the presence of pyrrole, a 0.5-ml. sample of pyridine is diluted with 2.5 ml. of water, and 2 ml. of concentrated hydrochloric acid is added followed by 0.5 ml. of a 5% solution of -dimethyl-aminobenzaldehyde in dilute hydrochloric acid (1 10 dilution of concentrated hydrochloric acid). If pyrrole is present, a red-purple color appears. Spectroquality pyridine gives a negative result in this test. 

Methyl groups at positions 2 and/or 4 of the pyrido[l,2-a]pyrimidinium salts may be condensed with p-dimethyl-aminobenzaldehyde in acetic anhydride.3,4,13... 

A colorimetric method for the analysis of etodolac has been reported which is based on the formation of colored complexes with p-dimethyl-aminobenzaldehyde in the presence of sulfuric acid and ferric chloride [19]. Absorbance measurements were made at 591.5 nm, and the method was found to be linear over the concentration range of 10 to 80 pg/mL. This method was used to determine etodolac in bulk powder and other dosage forms. 

The quantity of fat from the cocoa shell that ends up in the cocoa butter can be measured by testing with p-dimethyl-aminobenzaldehyde, which reacts with dried fruit pulp adhering to the shell. The reaction gives an intense fluorescence and has been used with TLC and fluorescence spectrophotometry (Kleinert, 1964). Shell fat is softer than nib fat because it contains higher levels of linoleic acid (18 2) and its presence softens the butter (Timms and Stewart, 1999). However, its presence can be usually due to poor separation of shell from nib rather than direct adulteration. 

Ethoxy-7-methoxy-2-methyl-l-benzotellurinium fluorosulfate reacted with 4-dimethyl-aminobenzaldehyde to form 2-[2-(4-dimethylaminophenyl)-ethenyl]-4-ethoxy-7-methoxy-1-benzolellurinium fluorosulfate1. 

When calycanthine is boiled in ethanol with a trace of p-dimethyl-aminobenzaldehyde (Ehrlich s reagent) and hydrochloric acid, it gives a clear pink color diagnostic of a monosubstituted indole. 

Reaction of compounds of the type 225 (R3 = CH3) withp-dimethyl-aminobenzaldehyde in pyridine or acetic anhydride gave 240,270 while the same compound with ethyl orthoformate gave a trimethine cyanine.270... 

Colour Tests. Ammoniacal Silver Nitrate—black p-Dimethyl-aminobenzaldehyde—red/- Ferric Chloride—green-brown Folin-Ciocalteu Reagent—blue Methanolic Potassium Hydroxide—red Millon s Reagent—red-orange Nessler s Reagent—black Palladium Chloride—orange - brown Potassium Dichromate—brown. 

The m-hydroxybenzoic acid is obtained in S>4% yield. m- and p-Dimethyl-aminobenzaldehydes are unaffected by concentrated potassium hydroxide solution. 

An alternative method of studying the reaction is by dinitrophenylation of the acid hydrazides (see above). The DNP derivatives are red in alkali and can be determined colorimetrically. Gallop et al. (1959) first used hydrazine to demonstrate ester links, but gave few details except that the fall of molecular weight was similar to that produced by hydroxylamine. The bound hydrazides were demonstrated by the reaction with p-dimethyl-aminobenzaldehyde, by dinitrophenylation, and by reduction of copper salts. 

This is obtained by reducing 3-methylamino-4-hydroxyph ylarsinic acid with hydrosuiphite. The dihydrochloride is a greyish-white, micro-crystalline powder. It gives a brownish-orange liquid with p-dimethyl-aminobenzaldehyde, but no subsequent precipitate separates as noted... 

Speculate on the structure of the compound formed when 4-dimethyl-aminobenzaldehyde is condensed with 4-chlorobenzaldehyde. 

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

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 ... 

In the light of the above facts, the behaviour of 4-(dimethyl)aminobenzaldehyde,... 

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