2-Bromobenzaldehydes

The crude product (Note 2) is transferred to a 2-I. flask and mixed thoroughly with 200 g. of powdered calcium carbonate. About 300 cc. of water is added and the mixture is heated cautiously (Note 3) and then refluxed for fifteen hours to effect hydrolysis. The product is then distilled in a rapid current of steam (Note 4), and the distillate is collected in soo-cc. portions, cooled, and the />-bromobenzaldehyde is collected and dried in a desiccator. From the first liter of distillate 50-60 g. of -bromo-benzaldehyde melting at 55-57° is obtained. An additional... 

Bromobenzaldehyde has been prepared by the oxidation of -bromotoluene with chromyl chloride/ by saponification of the acetal from />-bromophenylmagnesium bromide and orthoformic ester/ by the oxidation of ethyl -bromobenzyl ether with nitric acid/ by the oxidation of /j-bromobenzyl bromide with lead nitrate/ and by the hydrolysis of i-bromobenzal bromide in the presence of calcium carbonate. ... 

Z)-3-(Tributylstannyl)allylamine participates in a palladium-catalyzed cross-coupling reaction with 2-bromobenzaldehyde (73, R = H) to give 3//-2-benzazepine (75, R = H). A similar reaction with the corresponding acetophenone 73 (R = Me) produces 1 -methyl-3//-2-benzazepine (75 R = Me), whereas with ethyl 2-bromobenzoate (73, R = OMe), 3//-2-benzazepin-(12/7)-one (74) is formed.237... 

The submitters report that -bromobenzaldehyde may be prepared by the same procedure, substituting 62 g. (0.37 mole)... 

Bromobenzaldehyde, 17, 20 18, 62 Jl-BttOMOBF.NZALDrACETA.TF, 18, 63 J-Bromobenzoic acid, 17, 21 p-B romobiphenyl, 16, 85 ar-Bromo-iso-caproic acid, 11, 22 a-Bromo-B-caproic acid, 11, 22 Bromocyanogen, 11, 30 /9-Bromoethylamtoe hydrobromide, 18,13, 77... 

This category of primary synthesis is extremely rare in the quinoxaline series, although a few examples have been reported in recent literature. Thus a mixture of neat 1,2-benzenediamine (331) and an excess of p-bromobenzaldehyde heated at 350°C for 5 min afforded (with aerial oxidation ) 2,3-bis(p-bromophenyl) quinoxaline (332) in 50% yield " " and analogs were made similarly but usually in poor to mediocre yield after separation from byproducts." " In addition, an... 

A one-pot synthesis of thiohydantoins has been developed using microwave heating [72]. A small subset of p-substituted benzaldehydes, prepared in situ from p-bromobenzaldehyde by microwave-assisted Suzuki or Negishi reactions, was reacted in one pot by reductive amination followed by cyclization with a thioisocyanate catalyzed by polystyrene-bound dimethyl-aminopyridine (PS-DMAP) or triethylamine, all carried out under microwave irradiation, to give the thiohydantoin products in up to 68% isolated yield (Scheme 16). 

Bromobenzaldehyde and 4-fluorophenylboronic acid were coupled in DMF using tetrakis(triphenylphosphine)palladium(0) as catalyst [85] (see a more extended description in [42]). 

OS 45] [R 17] [noprotocol] For the reaction of 3-bromobenzaldehyde and 4-fluorophenylboronic acid, improved conversion was found for a micro reactor, composed... 

Organic synthesis 74 [OS 74] Reaction between 4-bromobenzaldehyde and the silyl enol ether of cyclohexane [15]... 

P 55] Before synthesis, a micro-mixing tee chip micro reactor (Figure 4.85) (with two mixing tees and four reservoirs) was primed with anhydrous tetrahydrofuran (THF). A 40 gl volume of a 0.1 M solution of tetrabutylammonium fluoride trihydrate in anhydrous THF is filled into one reservoir of a micro-mixing tee chip reactor [15], 40 gl of a 0.1 M solution of 4-bromobenzaldehyde in anhydrous THF is added to a second reservoir, 40 gl of a 0.1 M solution of the silyl enol ether (masking the enolate of a carbonyl compound such as cyclohexanone) in anhydrous THF is added to a third reservoir and anhydrous TH F is filled into the fourth collection reservoir. Electrical fields of417,455,476 and 0 V cm are applied to transport the reaction species from the respective reservoirs. The reaction is carried out at room temperature. 

OS 74] ]R 4b] ]P 55] For the reaction of 4-bromobenzaldehyde with the silyl enol ether of cyclohexanone, only 1% conversion was achieved on applying protocol [P 55] [15]. Changing the set of electrical fields so that the concentration of tetrabutylammonium fluoride trihydrate was raised resulted in 100% conversion (417, 341, 333 and 0 V cm" ). 

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