Formyl reaction

Hydroxy-4-methylthiazole failed to react when submitted to Friedel-Crafts benzoylation conditions (349) on the other hand, it reacted normally in Gattermann and in Reimer-Tiemann formylation reactions, affording the 5-formyl derivative (348). 4-Methylthiazole is insufficiently activated and fails to react under the same conditions. 2,4-Dimethylthiazole undergoes perfluoroalkylation when heated at 200° for 8 hr in a sealed tube with perfluoropropyl iodide and sodium acetate (116) (358). 

Alkyl substituents. The steric effect of 1-alkyl substituents in the pyrrole series has been demonstrated in, for example, Vilsmeier formylation reactions. Thus as the bulk of the alkyl substituent on nitrogen is increased e.g. from Me to Bu ) so does the proportion of /3 substitution (70JCS(C)2573). A similar trend has been observed in a series of experiments on the trifiuoroacetylation of A-alkylpyrroles with trifluoroacetic anhydride (80JCR(S)42). 

Imidazole, 2-ethyl-1 -(o-nitrophenyl)-cyclization, S, 431 Imidazole, 4-ethyl-2-phenyl-oxidation, S, 405 Imidazole, ethynyl-Michael addition, S, 437 Imidazole, 4-ethynyl-2-phenyl-synthesis, S, 494 Imidazole, 1-formyl-reactions, S, 452 Imidazole, 2-formyl-mass spectra, S, 360 Imidazole, 4-formyl-synthesis, S, 475-476 Imidazole, 2-formyl-1,5-dimethyl-mass spectra, S, 360 3-oxide... 

Pyrrole, l-(2-acylaminophenyl)-intramolecular aeylation, 4, 223 Pyrrole, 3-acyl-2-ehloromethyl-reactions, 4, 274 Pyrrole, 3-acyl-2-formyl-reactions... 

Thiophene, 2-amino-3-cyano-5-phenyl-synthesis, 4, 888-889 Thiophene, 3-amino-4,5-dihydro-cycloaddition reactions, 4, 848 Thiophene, 2-amino-3-ethoxycarbonyl-ring opening, 4, 73 Thiophene, 2-amino-5-methyl-synthesis, 4, 73 Thiophene, 2-anilino-synthesis, 4, 923-924 Thiophene, aryl-synthesis, 4, 836, 914-916 Thiophene, 2-(arylamino)-3-nitro-synthesis, 4, 892 Thiophene, azido-nitrenes, 4, 818-820 reactions, 4, 818-820 thermal fragmentation, 4, 819-820 Thiophene, 3-azido-4-formyl-reactions... 

In 1927 Putochin studied the effect of temperature on the nature of the products formed when the formylation reaction was carried out in benzene and observed that 1-formyl derivatives were the major products obtained at low temperatures, whereas the 3-formyl derivatives predominated at higher temperatures. Britton et al. in 1947 claimed that the formation of the 3 -formylindole derivative is probably favored, relative to the alternate 1-formylation process, by elevated temperatures and pressures.However, it was apparently not possible to suppress completely the formation of the 1-formyl derivatives and yields of the order of 40% of both products were usually obtained. 

Another formylation reaction, which is named after Gattermann, is the Gatter-mann-Koch reaction. This is the reaction of an aromatic substrate with carbon monoxide and hydrogen chloride (gas) in the presence of a Lewis acid catalyst. Similar to the Gattermann reaction, the electrophilic agent 9 is generated, which then reacts with the aromatic substrate in an electrophilic aromatic substitution reaction to yield the formylated aromatic compound 10 ... 

While the Friedel-Crafts acylation is a general method for the preparation of aryl ketones, and of wide scope, there is no equivalently versatile reaction for the preparation of aryl aldehydes. There are various formylation procedures known, each of limited scope. In addition to the reactions outlined above, there is the Vdsmeier reaction, the Reimer-Tiemann reaction, and the Rieche formylation reaction The latter is the reaction of aromatic compounds with 1,1-dichloromethyl ether as formylating agent in the presence of a Lewis acid catalyst. This procedure has recently gained much importance. 

The formylation of a phenol 1 with chloroform in alkaline solution is called the Reimer-Tiemann reaction. It leads preferentially to formation of an ortho-formylated phenol—e.g. salicylic aldehyde 2 —while with other formylation reactions, e.g. the Gattermann reaction, the corresponding /jara-formyl derivative is obtained as a major product. The Reimer-Tiemann reaction is mainly used for the synthesis of o-hydroxy aromatic aldehydes. 

The reaction of electron-rich aromatic compounds with yV,A -dimethylformamide 2 and phosphorus oxychloride to yield an aromatic aldehyde—e.g. 3 from the substituted benzene 1—is called the Vilsmeier reaction or sometimes the Vilsmeier-Haack reaction. It belongs to a class of formylation reactions that are each of limited scope (see also Gattermann reaction). 

With respect to aromatic substrates, the Vilsmeier formylation reaction works well with electron-rich derivatives like phenols, aromatic amines and aromatic heterocycles like furans, pyrroles and indoles. However various alkenes are also formylated under Vilsmeier conditions. For example the substituted hexatriene 6 is converted to the terminal hexatrienyl aldehyde 7 in 70% yield ... 

Several chlorophyll derivatives have been prepared by electrophilic substitution, inter alia by formylation reactions. Adopting methods from corrin chemistry.50 alkylation with chloro-methyl methyl ether (caution toxic),32k chloromethyl methyl sulfide,51 and dichloromethyl methyl ether (caution toxic)52 in the presence of Lewis acids are the methods of choice to introduce carbon residues into the chlorin frame work. The compounds listed below have been prepared by these methods. 

This review account will summarize latest research results on the design, development and properties of functionalized primary phosphines. In particular, the focus would be centered around recent results from our laboratory on the chemical architecture of heteroatom functionahzed primary bisphosphines. We wiU also discuss synthetic protocols for the formylation reactions of functionalized primary phosphines to produce structurally diverse water-soluble hydroxymethyl phosphines. Finally, we will discuss the utility of carboxylate functionahzed primary bisphosphines for incorporation on to peptides and their potential apphcations in catalysis and biomedicine. 

These thioether functionalized primary bisphosphines 9 and 10 showed modest oxidative stabilities and have found applications as novel precursors in the development of functionalized water-soluble phosphines via formylation reactions across P-H bonds (see below) [47]. 

At high pressures the presence of the H02 radical also contributes via HCO + H02 — H202 + CO, but H02 is the least effective of OH, O, and H, as the rate constants in Appendix C will confirm. The formyl radical reacts very rapidly with the OH, O, and H radicals. However, radical concentrations are much lower than those of stable reactants and intermediates, and thus formyl reactions with these radicals are considered insignificant relative to the other formyl reactions. As will be seen when the oxidation of large hydrocarbon molecules is discussed (Section H), R is most likely a methyl radical, and the highest-order aldehydes to arise in high-temperature combustion are acetaldehyde and propionaldehyde. The acetaldehyde is the dominant form. Essentially, then, the sequence above was developed with the consideration that R was a methyl group. 

Formylation reactions of organic halides, palladium-catalyzed, 26 330, 331 Fouling, 26 378... 

Group VA Donor Ligands. The paramagnetic compounds, [Co(CO)2(PR3)]3 (R3 = Bu5, Bu2 Ph, or Phj), have been isolated during stoicheiometric hydro-formylation reactions of linear a-olefins " viz ... 

Deuterium labelling can, in principle, provide mechanistic information on hydro-formylation reactions, but complications may arise if scrambling of the D-label bet veen a metal hydride and D2 is fast. The isotopic exchange reaction shown in Eq. (9) was probed by rapid scan HP IR spectroscopy (1.3 scans s" ) where 21 is the bidentate pyrrolyl-based phosphorus amidite ligand illustrated [8]. 

The steps in the hydro formylation reaction are closely related to those that occur in the Fischer-Tropsch process. The Fischer-Tropsch process is the reductive conversion of carbon monoxide to alkanes. It occurs by a repetitive series of carbonylation, migration, and reduction steps which can build up a hydrocarbon chain. 

Microemulsions with different structures, like micelles, reverse micelles or bicontinuous networks, can be used for several inorganic, organic [72] or catalytic reactions which require a large contact area between oil and water. Besides enzyme catalysis, this can be the formation of nanoparticles [54, 73, 74], hydro-formylation reactions [75] or polymerisations [76-78]. 

A similar mechanism may explain the formation of formate esters in the hydro-formylation reaction (90, 64). 

Similarly, poly (p-formyloxy styrene) (IV) can be prepared by formylation of poly(p-hydroxystyrene) using formic acid-acetic anhydride mixture as a formylating agent (Scheme 4). The formylation reaction is best... 

The reaction of phenol with isoprene dibromide and sodium affords ( )-2-isopropenyl-2,3-dihydrobenzofuran (219) in high yield (78CL253) an additional formylation reaction led to fomannoxin (220), a toxin isolated from Heterobasidion annosum (77TL651). ( )-Tremetone (221) was synthesized by the same route and oxidized by selenium dioxide in acetic anhydride to give ( )-5-acetyl-2-(l-acetoxymethylvinyl)-2,3-dihydrobenzofuran. 

Gray et a I.146 radiolabeled a PNA using [14C]formaldehyde in a reductive formylation reaction to specifically methylate the exocyclic amino groups of the nucleotide bases. 

C and a total pressure of 1-300 atm (the pressure of the hydro-formylation reaction), depending on the reactivity of the olefin. After the cobalt carbonyl hydride has passed from the aqueous phase into the organic phase (Reaction 3), stoichiometric hydroformylation (6, 7, 8) takes place (Reactions 4-8). 

The formylation reaction of vinylic, aryl, and heterocyclic halides proceeds in good yields, generally at 115 to 150° under several hundred pounds pressure. The hydrogenation does not take place at atmospheric pressure. Examples of the formylation reaction appear in Table IV. 

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