4- Chlorobenzaldehyde

Chlorobenzaldehyde [J04-88-]] M 140.6, m 47 . Crystd from EtOH/water (3 1), then sublimed twice at 2mm pressure at a temperature slightly above the melting point. 

Tetrasubstituted phosphonium halides are just as effective as their ammonium counterparts. A combination of tetraphenylphosphonium bromide and either 18-crown-6 or polyethylene glycol dimethyl ether with spray-dried potassium fluoride converts 4-chlorobenzaldehyde to 4-fluorobenzaldehyde in 74% yield [67] In addition, the halogen of a primary alkyl chloride or bromide is easily displaced by fluorine in aqueous saturated potassium fluoride and a catalytic amount of hexadecyltributylphosphonium bromide [68] (Table 7 Procedure 4, p 194)... 

A solution of 4-chlorobenzaldehyde is reacted with (3-mercaptopropionic acid and with methylamine. The mixture is refluxed in benzene and water is removed from an overhead separator. The reaction mixture was cooled, washed with dilute ammonium hydroxide and water, and the benzene was removed by distillation in vacuo. The oily residue was taken up in ether from which it crystallized. The precipitate was recrystallized twice from ether to yield 2-(4-chlorophenvl)-3-methyl-4-metathiazanone. 

Chlorobenzaldehyde Chlormezanone Chlorobenzene Methixene HCI p-Chlorobenzene sulfonamide Chlorpropamide... 

A mixture of 1.4 g (10 mmol) of 4-chlorobenzaldehyde and 0.71 g (5 mol %) of the chiral polymer E is stirred in 10 mL of dry toluene for 15 h, under a dry nitrogen atmosphere, to form the Schiff base. After cooling to 0lC, 15 mL (15 mmol) of 1 M diethyl/inc in hexane is added and the mixture is stirred for a further 24 h at O C. 1 N HC1 is then added dropwise at O C, and the chiral polymer is removed by filtration. The polymer is washed several times with 11,0 and Et,0. The aqueous layer is separated and extracted with Et20. The combined organic layer is dried over MgS04 and concentrated under reduced pressure. The crude product is purified by column chromatography (silica gel, CHC1,) yield 1.61 g (95 %) 99 % ee [a]2,0 —23.9 (r = 4.93, benzene). 

C7H5CIO 89-98-5) see Amlodipine Clobenzorex Clopidogrel hydrogensulfate Cloxacillin 4-chlorobenzaldehyde... 

The poor performance of the distyryldiphenyl derivative 11.15 at higher washing temperatures is a serious drawback in some countries. In an attempt to overcome this disadvantage, product 11.15 has been marketed in admixture with an analogous FBA (11.64) derived from 4-chlorobenzaldehyde-3-sulphonic acid (see Scheme 11.5). This much less soluble variant is highly effective at high washing temperatures. 

Multicomponent reaction of 2-aminomethylpiperidine benzyl isocyanate and 4-chlorobenzaldehyde in the presence of InCl3 as catalyst provided 4-benzylimino-3-(4-chlorophenyl)pyrido[l,2-+]pyrazinium chloride <2005OL2329>. First, a 3,4-dihydro-477 derivative was formed, which was oxidized under the reaction conditions. Reaction of... 

The nucleophilic displacement of suitable para substituents in analogues of malachite green is used as a means of synthesis of some important acid dyes. For example, Cl Acid Blue 83 (6.176 R = H) is made by the aldehyde method, using 4-chlorobenzaldehyde and N-ethyl-N-(3-sulphobenzyl)aniline. The resulting leuco base is oxidised to the colour salt,... 

The diendo- and diexo-norbornane- and norbornene-fused quinazolinones 272 and 273 were prepared from the corresponding carboxamides and 4-chlorobenzaldehyde (87CB259). 

Chlormezanone Chlormezanone, 2-(p-chlorophenyl)-tetrahydro-3-methyl-4H-l,3-tiazin-4-on-1,1-dioxide (5.2.8), is synthesized by joint condensation of mercaptopropionic acid, methylamine, and 4-chlorobenzaldehyde, evidently through the intermediate stage of formation of 4-chlorobenzylidenemethylamine, giving the aminothioacetal 2-(p-chlorophenyl)-tetrahydro-3-methyl-4H-l,3-tiazin-4-one (5.2.7). Oxidation of the sulfur atom using potassium permanganate gives chlormezanone (5.2.8) [62,63]. 

Chloropyramine Chloropyramine, iV-(4-chlorobenzyl)-iV, iV -dimethyl-iV-2-pyridylethyl-enediamine (16.1.9), is synthesized in a somewhat different manner, which is by reacting 2-brompyridine with iV-(4-chlorobenzyl)-iV, Af -dimethylethylenediamine (16.1.8). iV-(4-Chlorobenzyl)-iV, iV -dimethylethylenediamine (16.1.8), in turn, is synthesized by condensation of 4-chlorobenzaldehyde c iV,iV-dimethylethylenediamine with subsequent reduction of the imine group [13-19]. 

In the Sepracor synthesis of chiral cetirizine di hydrochloride (4), the linear side-chain as bromide 51 was assembled via rhodium octanoate-mediated ether formation from 2-bromoethanol and ethyl diazoacetate (Scheme 8). Condensation of 4-chlorobenzaldehyde with chiral auxiliary (/f)-f-butyl sulfinamide (52) in the presence of Lewis acid, tetraethoxytitanium led to (/f)-sulfinimine 53. Addition of phenyl magnesium bromide to 53 gave nse to a 91 9 mixture of two diastereomers where the major diasteromer 54 was isolated in greater than 65% yield. Mild hydrolysis conditions were applied to remove the chiral auxiliary by exposing 54 to 2 N HCl in methanol to provide (S)-amine 55. Bisalkylation of (S)-amine 55 with dichlonde 56 was followed by subsequent hydrolysis to remove the tosyl amine protecting group to afford (S)-43. Alkylation of (5)-piperizine 43 with bromide 51 produced (S)-cetirizine ethyl ester, which was then hydrolyzed to deliver (S)-cetirizine dihydrochloride, (5)-4. 

Schiff bases (112) derived from 4-chlorobenzaldehyde and 1-substituted-5-amino-3-methylthio-l,2,4-triazoles (111) underwent cyclization with phe-noxyacetyl chloride or dichloroacetic acid in the presence of phosphoryl chloride and dimethylformamide to give the 7-(4-chlorophenyl)-fram-6,7-dihydro-3-methylthio-6-phenoxy-l-substituted-l,2,4-triazolo[4,3-a]pyrimidin-5-one 113 and l-substituted-6-chloro-7-(4-chlorophenyl)-3-methylthio 1,2,4-triazolo[4,3-a]pyrimidin-5-one 114, respectively (88JHC173) (Scheme 47). 

Compared with asymmetric ethylation, reports on asymmetric phenylation are limited. We disclosed the enantioselective phenylation using diphenylzinc prepared in situ from phenyl Grignard reagent and zinc chloride. This method needs a stoichiometric amount of chiral amino alcohol DBNE 18 but good ee of 82% was achieved [32], A catalytic phenylation was examined using planar chiral compound 1 based on ferrocene, and chiral diaryl carbinols of moderate ee were provided from diphenylzinc and 4-chlorobenzaldehyde (Scheme 10) [33]. A catalytic and highly enantioselective phenylation was realized by binaphthyl-based chiral catalyst 23. In this reaction, the addition of 2 equivalents of diethyl-zinc against catalyst increases the yield and ee [34]. Recently, chiral amino alcohol DPMPM 9 was also reported to be an efficient catalyst for asymmetric phenylation [35]. 

In rare cases, the one-electron oxidized products are also readily oxidized, and the three-electron oxidized product is observed. A case in point is the oxidation of the 4-chlorobenzyl radicals by Fe(CN)63 to the corresponding benzaldehyde. The 4-chlorobenzylalcohol is not the intermediate that is further oxidized by Fe(CN)63, and thus the mechanism of the formation of 4-chlorobenzaldehyde is rather complex (Merga et al. 1996). Since Fe(CN)63 is commonly used as a simple and effective oxidant also in DNA free-radical chemistry, such potential complexities have to be kept in mind. 

Fig. 11.5 (A) Eigen-type plot for the general base-catalysed reactions of 4-chlorobenzaldehyde with a substituted hydrazine [8] the line is calculated from log kg = —0.341 log(1 + 106 09 pffa). (B) Eigen-type plot for general acid catalysis in the reaction of cyanic acid (HNCO) with aniline, and an alternative interpretation [9] the dashed line has a Bronsted slope of —0.19 and the break at p/fa near 10 in the solid line is consistent with proton transfer to an addition intermediate (PhNH2+CONH ).

Fig. 11.7 (A) E1cB mechanism for the elimination reactions of 4-nitrophenylethylpyridinium ions catalysed by OH deprotonation is rate limiting at pKa s below the breakpoint data are from reference [16] and the line is calculated from Eqaution 11.11. (B) Effect of increasing 3-quinuclidinol buffer concentration on the rate constants for 2-methyl-3-thiosemicarbazone formation from 4-chlorobenzaldehyde at pH 11.10 results are consistent with a change in the rate-limiting step from proton transfer to formation of the intermediate data from reference [8],...

Electrochemical trifluoromethylation of 4-chlorobenzaldehyde preparation of 2,2,2-trifluoro-1-(4-chlorophenyl)ethanol6... 

Introduce into the cell dry DMF (40 mL), purge with argon, add tetrabutylammonium bromide (322 mg, 1 mmol), 4-chlorobenzaldehyde (2.81 g, 20 mmol), and stir the mixture. 

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