DiMethyl amino benzaldehyde and

Note It is reported that the use of chlorobenzene as solvent is essential when the reagent is to be used to detect aromatic amines [1]. In the case of steroids, penicillins, diuretics and alkaloids the reaction should be accelerated and intensified by spraying afterwards with dimethylsulfoxide (DMSO) or dimethylformamide (DMF), indeed this step makes it possible to detect some substances when this would not otherwise be possible [5,9-11] this latter treatment can, like heating, cause color changes [5,9]. Penicillins and diuretics only exhibit weak reactions if not treated afterwards with DMF [10, 11]. Steroids alone also yield colored derivatives with DMSO [9]. Tlreatment afterwards with diluted sulfuric acid (c = 2 mol/L) also leads to an improvement in detection sensitivity in the case of a range of alkaloids. In the case of pyrrolizidine alkaloids it is possible to use o-chloranil as an alternative detection reagent however, in this case it is recommended that the plate be treated afterwards with a solution of 2 g 4-(dimethyl-amino)-benzaldehyde and 2 ml boron trifluoride etherate in 100 ml anhydrous ethanol because otherwise the colors initially produced with o-chloranil rapidly fade [12]. 

Method using Dimethyl Amino Benzaldehyde—Diphenylamine Paper. Phosgene, even if present in traces in the air, can be detected by means of papers prepared with dimethyl amino benzaldehyde and diphenylamine. 

Identification of trichloromethyl chloroformate may also be made by using dimethyl amino benzaldehyde and diphenylamine paper, prepared as described on p. 81. In presence of trichloromethyl chloroformate this turns yellow as in the presence of phosgene. 

The relative reactivities of indole, 2- and N-methylindole, pyrrole, thiophene, and furan have been determined in alkylation by a benzenonium ion coordinated to iron tricarbonyl (73CC540). The effects of methyl substituents in pyrrole were determined in alkylation by 4-(7V,7V-dimethyl-amino)benzaldehyde [76JCS(P2)696]. In neither of these methods, nor in the alkylation of indole by aziridinium tetrafluoroborate [67AG(E)178], nor in self-alkylation of a X5-phosphorinyl tetrafluoroborate [73AG (E)753], is a catalyst required. 

These papers are specific for phosgenfe and are more sensitive than the dimethyl amino benzaldehyde papers. Sensitivity o 8 mgm. of phosgene per cu. m. of air. ... 

The colorimetric methods recommended for the determination of total fusel oil contents in beverages are based on a color reaction. In this reaction, 2-methyl-l-propanol, 2-methyl-l-butanol, and 3-methyl-l-butanol lose water during heating in a strongly acidic solution and the unsaturated hydrocarbons formed yield colored complexes with vanillin, salicylaldehyde, and 4-dimethyl-amino-benzaldehyde. The absorbance is measured spectro-photometrically at 445 and 560 nm. 

Diethyl dl-1 -aminobenzylphosphonate has been prepared by a Mannich reaction of diethyl phosphite, benzaldehyde, and ammonia, resolved as its D-mandelate salt, and hydrolysed to give (+)-l-aminobenzylphosphonic acid.27 While the tetraethyl-diamide (33) reacts with benzaldehyde to give the expected phosphonic diamide (34), the corresponding tetramethyl-diamide reacts, with migration of the dimethyl-amino-group, to give (35).28... 

Normal nucleophilic substitution reactions of alkyl and aryl chloropyrazines have been examined as follows 2-chloro-3-methyl- and 3-chloro-2,5-dimethyl(and diethyl)pyrazine with ammonia and various amines (535, 679, 680) 2-chloro-3(and 6)-methylpyrazine with methylamine and dimethylamine (681, 844), piperidine and other amines (681, 921) 2-chloro-5(and 6)-methylpyrazine with aqueous ammonia (362) alkyl (and phenyl) chloropyrazines with ammonium hydroxide at 200° (887) 2-chloro-3-methylpyrazine with aniline and substituted anilines (929), and piperazine at 140° (759) 2-chloro-3-methyl(and ethyl)pyrazine with piperidine (aqueous potassium hydroxide at reflux) (930,931) [cf. the formation of the 2,6-isomer( ) (932)] 2-chloro-3,6-dimethylpyrazine with benzylamine at 184-250° (benzaldehyde and 2-amino-3,6-dimethylpyrazine were also produced) (921) 2-chloro-3,5,6-trimethylpyrazine with aqueous ammonia and copper powder at 140-150° (933) and with dimethylamine at 180° for 3 days (934,935) 2-chloro-6-trifluoromethylpyrazine with piperazine in acetonitrile at reflux (759) 2-chloro-3-phenylpyrazine with aqueous ammonia at 200° (535) 2-chloro-5-phenylpyrazine with liquid ammonia in an autoclave at 170° (377) 2-chloro-5-phenylpyrazine with piperazine in refluxing butanol (759) but the 6-isomer in acetonitrile (759) 5-chloro-2,3-diphenylpyrazine and piperidine at reflux (741) and 5-chloro-23-diphenylpyrazine with 2-hydroxyethylamine in a sealed tube at 125° for 40 hours (834). 

Illustrated below is the mechanism of the reaction between benzaldehyde and dimethyl O -amino acetaldehyde. 

Benzaldehyde and a little acetic acid added to an ethanolic soln. of 3-(o-amino-anilino)-5,5-dimethyl-2-cyclohexen-l-one, and allowed to stand 1 hr. at room temp. 3,3-dimethyl-2,3,4,5,10,ll-hexahydro-ll-phenyl-lH-dibenzo[b,e][l,4]di-azepin-l-one. Y 94.3%. F. e, s. S. Miyano and N. Abe, Chem. Pharm. Bull. 20, 1588 (1972). 

Benzaldehyde dimethyl acetal 121 reacts, for example, with the silylated allylic alcohol 645, in the presence of SnCl2-MeCOCl, via an intermediate analogous to 641, to the 3-methylenetetrahydrofuran 646 and methoxytrimethylsilane 13 a [182], whereas benzaldehyde dimethyl acetal 121 reacts with the silylated homoallylalco-hol 640 in the presence of TMSOTf 20 to afford exclusively the ds 4-vinyltetrahy-drofuran 647 and 13 a [183]. A related cyclization of an a-acetoxy urethane 648 containing an allyltrimethylsilane moiety gives the 3-vinylpyrrohdine 649 in 88% yield and trimethylsilyl acetate 142 [184, 185]. Likewise, methyl 2-formylamido-2-trimethylsilyloxypropionate reacts with allyltrimethylsilane 82 or other allyltri-methylsilanes to give methyl 2-formamido-2-aUyl-propionate and some d -unsatu-rated amino acid esters and HMDSO 7 [186] (Scheme 5.56). 

An amino alcohol was found to accelerate the addition reaction of diethlylzinc to aldehyde [8], and then chiral amino alcohols were proved to be efficient chiral catalysts for asymmetric alkylation by using dialkylzinc reagents [9], Oguni reported a remarkable asymmetric amplification in chiral amino alcohol-promoted alkylation (Scheme 9.4). In the presence of (-)-l-piperidino-3,3-dimethyl-2-butanol (5) of 11% ee, benzaldehyde is alkylated enantioselectively to give (/ )-l-phenylpropanol with 82% ee [10]. Asymmetric amplification was also observed by Noyori using partially resolved (2.S )-3-exo-(dimethylamino)isobomeol (6) [11]. 

The amino group of hydrazides react with aldehydes and ketones. For example, 2-hydrazinocarbonylpyrazine refluxed with acetone-ethanol gave 2-isopropylidene-hydrazinocarbonylpyrazine (51) [which was reduced in methanol over palladium-charcoal to 2-(2 -isopropylhydrazinocarbonyI)pyrazine] (1366,1428,1429). Other references to similar reactions include the following reactions 2-hydrazinocarbonylpyrazine with p-acetamidobenzaldehyde (138) 4-hydroxy-, 4-hydroxy-3-methoxy-and 2-carboxy-3,4-dimethoxybenzaldehydes (1319) furfural (1201) and pyruvic acid (1201) 2-amino-3-hydrazinocarbonylpyrazine with acetone and benzaldehyde (1214) and 2-hydrazinocarbonyl-5,6-dimethyl-3-methylaminopyrazine with acetone (428). 

To a solution of 0.51 g (/ )-(+)-2-phenylglycinol (3.72 mmol) in 10 mL dry toluene containing 0.5 g 3A molecular sieves was added 0.38 mL benzaldehyde (3.74 mmol), and the resulting solution was stirred at room temperature for 2 h until an aliquot showed completion by the presence of the imino proton at 8 8.51. The reaction was filtered through Celite, and 0.31 mL dimethyl thiophosphite (3.69 mmol) was added. The reaction mixture was stirred at 0°C for 12 h, concentrated to an oil and subjected to column chromatography using hexanes/Et20 as the eluent. A major diastereomer of 0,0-dimethyl (R5)- [(l/ )-2-hydroxy-1 -phenylethyl]amino (phenyl)methyl-phosphonothioate, in the amount of0.578 g was obtained, in a yield of 44.2%, and 0.14 g minor diastereomer (10.7%) and 0.27 g diasteromeric mixture (20.6%) were obtained as well. 

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