2-formylphenyl

Sodium pyrazolate and 3,5-dimethylpyrazolate, [( " -cod)Rh(/A-Cl)]2, carbon monoxide, 3-(diphenylphosphino)benzoic acid, or (2-formylphenyl)diphenyl-phosphine give rise to complexes 120 (R = H, Me) and 121 (R = H, Me) [94JOM(469)213]. However, 2-(diphenylphosphino)benzoic acid (the carboxyl group in the ortho position) leads to formation of the mononuclear complexes 122. The products appear to be catalysts for hydroformylation reactions [93MI2]. 

Chiacchio and co-workers <97T13855> reported a stereoselective synthesis of 133 via an intramolecular 1,3-dipolar cycloaddition. Intermediate 132 was generated in situ by the reaction of tra .v-/V-(2-formylphenyl)-i -methyl-2-phcnylcthenc- l -sulfonamide 131 with N-methylhydroxylamine and afforded a tricyclic benzothiazine 133 in 51% yield (Scheme 36). 

Since the pioneering synthesis of this type of glycoconjugate first described by Maillard el al. in the late 1980s via condensation of 2-formylphenyl tetra-O-acetvl-/)-D-glucopyranoside with pyrrole,132 improved synthetic methodologies have generated... 

Finally, Schiff base macrocycles incorporating telluroether functions are obtained by condensation of fe(2-formylphenyl)telluride with 1,2-diamino-ethane (analogues with Se incorporated have also been prepared).8,114... 

Carboxybenzotellurophene A mixture of 15.5 g (53 mmol) of 2-formylphenyl car-boxymethyl tellurium, 50 niL of pyridine and 50 niL of acetic anhydride is heated under reflux for 2 h. Most of the solvent is then evaporated under vacuum, and the residue is extracted with boiling of 1 M aqueous sodium hydroxide solution. The extract is neutralized, the precipitate is filtered off and the solid is recrystallized from ethanol/benzene. Yield 11.6 g (80%) m.p. 206-208°C. 

Esterification of salicylaldehydes with acetic acid derivatives forms 2-formylphenyl acetate intermediates, which cyclize in high yield to afford 3-substituted coumarins (Scheme 168) <2004SC3129>. 

Formylphcnyl tellurium bromide and benzenethiol in refluxing pyridine produced 2-formylphenyl phenylthio tellurium2. 

Formylphenyl Phenylthio Tellurium2 2.5 g (8.0 mmol) of 2-formylphenyl tellurium bromide are dissolved in 25 ml of pyridine, 0.88 g (8.0 mmol) of benzenethiol are added, and the mixture is heated under reflux for 2 h. The resultant mixture is poured into aqueous hydrochloric acid/ice and extracted with chloroform. The organic phase is separated, dned, filtered, and chloroform is distilled from the filtrate. The residue is recrystallized from hexane/benzene yield 1.4 g (50%) m.p. 73°. 

Bis[2-formylphenyltelluro] selenium was converted upon sublimation under reduced pressure to bis[2-formylphenyl] ditellurium and 2-formylphenyl 2-formylphenyltelluro... 

Hydrogen chloride converted bis[2-formylphenyltelluro] selenium quantitatively to 2-formylphenyl tellurium chloride2. 

R = H X = Cl 2-formylphenyl tellurium chloride4 X = Br 2-formylphenyl tellurium bromide4 X = J 2-formylphenyl tellurium iodide4 R = CH3 X - Br 2-ace tylphenyl tellurium bromide4... 

SchiflF bases of 2-formylphenyl butyl tellurium reacted with the stoichiometrically required amounts of thionyl chloride3, sulfuryl chloride4-5, bromine3-5 or iodine4-5 to produce the tellurium halides that are stabilized by coordination between the tellurium and nitrogen atoms. 

The Schiff base prepared from 2-formylphenyl butyl tellurium and 1,2-diaminoethane and a five-fold molar excess of bromine reacted to give the tellurium bromide3. With thionyl chloride the corresponding tellurium chloride (m.p. 246-248-1, from benzene) was obtained in 70% yield3. 

Refluxing a solution of 2-formylphenyl tellurium bromide, hydroxylaminc hydrochloride, and potassium acetate in absolute ethanol produced the corresponding oxime2. 

The Schiff base prepared from 2-formylphenyl butyl tellurium and 1,2-diaminoethane was converted to tellurium trihalides by excess sulfuryl chloride or bromine2. 

Formylphenyl ethyl tellurium was obtained by lithiation of 1,3-dimethyl-2-phenylimidazolidine, reaction of the lithiated product with diethyl ditellurium, and hydrolytic cleavage of the imidazolidine ring1. 

Formylphenyl Methyl Tellurium1 20 g (0.05 mol) of 2-formylphenyl dimethyl telluronium iodide are dissolved in 100 m/of pyridine and the solution is heated under reflux for 3 h. The solution is then cooled and poured into a mixture of ice and dilute hydrochloric acid. The mixture is extracted with diethyl ether, the extract is washed with water, dried with magnesium sulfate, the solvent is distilled off, and the residue is fractionally distilled under vacuum yield 9.8 g (77%) b.p. 120 13070.1 torr (13.3 Pa). 

The alkyltelluro group is generally introduced into aldehydes and ketones protected in the form of their acetals. The acetal groups in the protected acetylphenyl alkyl and 2-formylphenyl alkyl tellurium compounds are hydrolyzed by strong sulfuric or hydrochloric acid to carbonyl groups without affecting the C — Te — C moiety. 

Butyl 2-Formylphenyl Tellurium5 A well-stirred mixture of 9.0 g (25 mmol) of butyl 2-(diethoxymethyl)-phenyl tellurium and 10 ml of concentrated hydrochloric acid is heated for 0.5 h. The solution is then cooled, extracted with diethyl ether, the extracts are dried with anhydrous magnesium sulfate, the solvent is evaporated, and the residue is distilled under reduced pressure yield 5.5 g (80%) b.p. 140-142°/0.1 torr. 

The oxidation of the formyl group in 2-formylphenyl butyl tellurium by silver oxide gave bis[2-curboxyphenyl] ditellurium in addition to the expected butyl 2-carboxyphenyl tellurium6. 

Dimethyl 2-Formylphenyl Telluronium Iodide3 10 g (2.1 mmol) of 2-(diethoxymethyl)phenyl dimethyl telluronium iodide are added to 100 ml of 4 molar hydrochloric acid, the mixture is heated with stirring for 2 h, cooled, and the solid is filtered off yield 7.4 g (90%) m.p. 125-130° (from glacial acetic acid or methanol). 

Suitably substituted phenyl alkyl tellurium derivatives are potential starting materials for the preparation of benzotellurophenes. Two examples of these reactions have been reported in the literature1, z. 2-R-carbonylbenzotellurophenes were obtained in 80% yield by refluxing 2-formylphenyl R-carbonylmethyl telluriums in a mixture of pyridine/acetic anhydride1,3. 

---