P-Dimethylaminobenzaldehyde

Amongst products isolated from Heliotropium spathulatum (Boraginaceae) were 9 mg of a new alkaloid which gave a positive Ehrlich reaction with p-dimethylaminobenzaldehyde The molecular formula determined by mass spectrometry is CisH2sNOs. What is the structure of the alkaloid given the set of NMR results 54 Reference is useful in providing the solution to this problem. Conditions CDCI3, 9 mg per 0.3 ml, 25 °C, 400 MHz ( //), 100 MHz ( C). (a) HH COSY plot ... 

All acid-catalyzed electrophilic substitution reactions are held by Treibs to occur by way of the distinct reactive species (23), thus the very greatly accelerated interaction of pyrrole and formaldehyde in acid solution involves attack of neutral formaldehyde on (23). Another example is the interaction of 2,3,4,6-tetramethylpyrrole with p-dimethylaminobenzaldehyde in acid solution, for which the following reaction (Scheme 2) is given,(23a) being presumably intended... 

Diacyl peroxide] = [amine] = 1.0 x 10 mol/L,45 C HDMA p-hydroxymethyl-A/,A/-dimethylaniline NDMA p-nitro-A/,A/-dimethylani-line DMAB p-dimethylaminobenzaldehyde. 

Patel and Naravane have published an assay utilizing p-dimethylaminobenzaldehyde and nitrite154. 

A frequently reported spectrophotometric technique for the determination of hydralazine is based on reactions with aromatic aldehydes to form hydrazones with absorption in the visible region. Luk yanchikova et al (5 +) used p-nitrobenzaldehyde Wesley-Hadzija and Abaffy (55) and Ruggieri (56) used p-dimethylaminobenzaldehyde Luk yanchi-kova (57,58) used cinnamaldehyde Schulert (33) used p-hydroxybenzaldehyde and Zak et al (59) used p-methoxy-benzaldehyde, after testing cinnamaldehyde, salicylaldehyde, 3, +,5-trimethoxybenzaldehyde, and 1-naphthaldehyde. 

The conversion of a Grignard or an organolithium reagent to an aldehyde has been accomplished by a variety of reagents. The methods include such reagents as N-ethoxymethyleneaniline 2 ethyl ortho-formate 2" p-dimethylaminobenzaldehyde 25 dimethyl formamide 3 a... 

Ehrlich p-Dimethylaminobenzaldehyde (100 g l"1) in cone. HC1. Mix 1 volume with 4 volumes of acetone. No heat required. Reacts within 20 min Trp Citrulline Pink/red Yellow Some indoles, aromatic amines and ureides react. Use after ninhydrin in multiple-dip sequences... 

Compounds 122, prepared from benzotriazole, p-dimethylaminobenzaldehyde and primary aromatic amines, are decomposed to the secondary amines 123 by sodium tetrafluoroborate124. 

Hydroxyproline assay. Hydroxyproline was determined according to Jamall et al. (1981). The assay employs p-dimethylaminobenzaldehyde (Ehrlich s reagent), which forms colored products with pyrroles originating from hydroxyproline oxidation. The values thus determined for hydroxyproline mass were multiplied by 8.0 to obtain the corresponding collagen mass. 

Reaction of the amine with p-dimethylaminobenzaldehyde (Ehrlich reagent) or p-diethylaminobenzaldehyde to produce a colored Schiff base [23—25]. The color formation is ascribed to a resonance hybrid between a protonated Schiff base and a quinoid system (Eq. (2)) ... 

Other reactions with electrophiles that have been recorded are those with aryldiazonium salts, with p-dimethylaminobenzaldehyde, and with alkyl halides. 

Phenyl isocyanate reacts with p-dimethylaminobenzaldehyde at 190°C to give the imine in quantitative yield [50],... 

Methylquinolizinium iodide (21, X = I) has been condensed with p-dimethylaminobenzaldehyde to yield the corresponding styryl derivative (22). Reaction of the same compound with p-nitrosodi-methylaniline affords the Schiff base 23.6 The simple 2-styrylquino-lizinium bromide was reported recently by Hansen and Amstutz.14... 

Procedure. Transfer ca 0.2-g accurately weighed sample to a 100-ml vol flask and add distd w to the mark. Stopper and shake until completely dissolved. Pipette out 5 ml and add 1 ml of the reagent (prepd by dissolving 1 g of p-dimethylaminobenzaldehyde in 50 ml absol ale and 5 ml coned HCl). If hydrazinium ion is present, the soln turns yel at first and then, after 10-15 mins, intensely red-orange. Compare the intensity of coloration of similarly treated solns (standards) contg 0.0001 mg to 1 mg of NaH4 per ml... 

Condensation of 2-methyl-4-phenylpyrimido[2,l-a]isoquinolinium perchlorate (173) with p-dimethylaminobenzaldehyde in acetic acid at 120-125°C for 10 min gave 2-(p-dimethylaminostyryl) derivative 174 (74KGS1148). Reaction of 1 lb-methyl-1,3,4,6,7,1 lb-hexahydro-2/f-pyrimido[2,l-a]isoquinolin-2-one (111) with aromatic aldehydes in acetic acid in the presence of acetic anhydride at 100°C for 4-5 h afforded lib-sty ryl derivatives (175) (93KGS499). 

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