Formyl compounds

A convenient synthesis of A -3-ketones in the 5 5 series uses DDQ in one step. This introduction has to be done indirectly because of the unfavorable direction of enolization. In this scheme, advantage is taken of the equilibrated formylation at C-2 of 5i5-3-ketones. Dehydrogenation of the 2-formyl derivative (72) proceeds rapidly with DDQ and deformylation is achieved in the presence of a homogeneous catalyst. A related approach involves preparation of the 2i -bromo-5i5-3-ketone by bromination of the 2-formyl compound (72). ... 

The preparative value of this compound lies in the surprising fact that bis(l,3-diphenylimidazolidinylidenc-2) behaves in many reactions ie.g., with aromatic aldehydes,2,7 and with carbon acids 2 7-fJ) as if it dissociated to form a nucleophilic carbene. The hydrolytic cleavage of these derived imidazolidine derivatives makes possible the preparation of formyl compounds, so that the amino olefin can be considered as a potential carbonyla-tion reagent. In many reactions it is not necessary to isolate... 

Crude product. b Determined by HNMR. c Mixture of C-6 isomers (—1 1). d Mixture of C-8 isomers (-1 1). e Obtained as the 6-formyl compound. 

Benzene and naphthalene compounds can be formylated under Vil-smeir conditions. The formyl compounds, with or without isolating, can be condensed with amino arenes to give leuco compounds. In this reaction, the benzhydrol intermediate is not isolated.21,79,84 86 The reaction is generally carried out in an alcohol solvent such as isopropanol, butanol, or pentanol and an acid catalyst such as hydrochloric acid, sulfuric acid, or methanesul-fonic acid.87 Acetic acid can also be used both as catalyst and as the solvent. Urea sometimes is added as catalyst.84,88 Terephthaldehyde reacts with W-diethyl-3-methylaniline89 and substituted azulenes to give a bis-triphenylmethane21 57 and 58, respectively. 

Thus, the rule of Keulemans (49), that a-quaternary carbon formyl compounds are not formed, was followed. The olefin isomerized to allow formyl attachment to a primary carbon atom. Addition of phosphine, which decreases isomerization, resulted in no reaction. 

The corresponding reaction with formaldehyde gave HOs3(OMe)(CO)10, and this is thought to occur via the bridged formyl compound, R = H. 

From these observations they concluded that 5fHi,F is rapidly metabolized to 5mHi,F, although a very small amount may be absorbed as the intact 5-formyl compound. Perry and Chanarin49 found similar results in urine samples. 

Azulene-substituted methyl cations were prepared as illustrated in Figure 7. The hydro derivatives (7a-d) became good precursors for the methyl cations. These derivatives were readily obtained by the reaction of azulenes 6a-d with 1-formyl compounds 5a-d under acidic conditions. The synthesis of the tri(l-... 

The potassium compound 19 is readily transformed into 20 (R = alkyl) by the action of alkyl halides. The products are converted into salts of alkylamines RNH2 by acidic hydrolysis50. Uses of di-t-butyl imidodicarboxylate (21) have been reviewed46. Treatment of formamide with di-t-butyl dicarbonate 22 gives the unstable formyl compound 23, which yields 21 by the action of 2-diethylaminoethylamine (equation 18)51. 

It is reasonable to assume that the initial step in the cycloaddition reaction is an electrophilic attack by the carbene on the nitrogen atom to form the A -ylid. Where proton shift is possible, cyclization does not occur and the A-ylid produces the N-formyl compound (Scheme 7.30) [36]. 

The general principle of methyl group reactivity is also seen in the oxidation of 7,9,10-trimethylbenz[c]acridine to give the 7-formyl compound (68), the 9- and 10-methyl groups being unaffected (Scheme 62) (64JCS5622). 

The condensation of 5-acetyl derivative 404 instead of the corresponding 5-formyl compound, with ethyl acetoace-tate, ethyl benzoylacetate, and diethyl acetone-1,3-dicarboxylate, by heating in the absence of base gave the respective 6-acylpyrido[2,3-4]pyrimidin-7(8//)-ones 406. The reaction of 404 with diethyl malonate afforded the 6-carboxylate 407 <2005RCB784>. Reaction of 405 with triethyl phosphonoacetate yielded 408 <2001W02001070741>. 

In contrast to the reactivity of the nitroethylenes, acrylonitrile generally reacts with indoles to form the l-(2-cyanoethyl) derivatives (B-70MI30500,79MI30501), whereas Michael addition at the 3-position requires the catalytic effect of copper(II) salts. The addition-elimination reaction of pyrroles and indoles with l,l-dicyano-2-ethoxyethylene proceeds in low yield (<30%) to give the dicyanovinyl derivatives, which can be converted by standard procedures into the formyl compounds (81H(16)1499). Tetracyanoethylene forms charge transfer complexes with indoles, which collapse to the Michael adduct anions and subsequently eliminate a cyanide ion with the formation of the tricyanovinylindole (B-70MI30500). 

Russian workers (74KGS58) carried out Vilsmeier reactions on 4,5-disubstituted 2-acylthienylamines and cyclized the resulting 3-formyl compounds with substances containing active methylene groups (Scheme 60). A versatile new synthesis of thieno[2,3-6]pyridines is also based on the Vilsmeier formylation of 2-acetamidothiophenes. Whereas with equimolar amounts of DMF and phosphorus oxychloride 3-formyl derivatives are obtained,... 

The conversion of CO + H2 (syn-gas) to hydrocarbons and oxygenates (Fischer-Tropsch chemistry)119 is of considerable industrial importance and recently the activation and fixation of carbon monoxide in homogeneous systems has been an active area for research.120,121 The early transition elements and the early actinide elements, in particular zirconium124 and thorium,125 126 supported by two pentamethylcyclopentadienyl ligands have provided a rich chemistry in the non-catalytic activation of CO. Reactions of alkyl and hydride ligands attached to the Cp2M centers with CO lead to formation of reactive tf2-acyl or -formyl compounds.125,126 These may be viewed in terms of the resonance forms (1) and (2) shown below. 

Depending on the work-up conditions, Vilsmeier-Haack formylation of 4-oxo-6,7,8,9-tetrahydro-4//-pyrido[l,2-a]pyrimidines gave various 9-sub-stituted pyrido[l,2-a]pyrimidines (240 -242).284,319 The 9-aminomethylene derivatives (240) were transformed by hydrolysis in 0.5 N hydrochloric acid to the 9-formyl compounds (241 R3 = H), by ethanolic hydrogen chloride to... 

The commonly encountered compounds in this class are the formyl, acetyl and benzoyl derivatives. The formation of the N-formyl compound is readily accomplished by heating the amino compound with formic acid in the presence of acetic anhydride.223 Alternatively, formic acid in the presence of dicyclohexl-carbodiimide (DCC) in pyridine solution is a suitable method for the protection of amino acid esters.224... 

AT-Formylnor-reticuline, on treatment with 2,3-dichloro-5,6-dicyano-l,4-benzoquinone in methanol, is oxidized to the 4-methoxy-compound (35), which can be cyclized to N-norbisnorargemonine (36) (converted by N- and O-methylation into argemonine) by mineral acid or to the isopavine N-formyl-northalidine (37) by treatment with methanesulphonic acid in acetonitrile. The N-formyl compounds can be reduced to AT-methyl by borane or converted into the secondary bases by hydrazinolysis.69... 

Three hemolytic constituents were isolated from the Japanese hy-droid Solanderia secunda and identified as l-hexadecyl-sn-glycerol-3-phosphorylcholine (311), 1 -tetradecyl-sw-glycerol-3-phosphorylcholine (312), and l-(l-hexadecenyl)-s/i-glycerol-3-phosphorylethanolamine (313) (254) Eighteen long-chain aliphatic a,w-bisisothiocyanates (314-331) and three a-isothiocyano-w-formyl compounds (332-334) were isolated from a Fijian sponge (Pseudaxinyssa sp.) (255). 

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