Heterocyclic carbonyls

Figure 4 IR frequencies (cm ) for keto heterocycles (carbonyl stretching frequencies bracketed frequencies are for C=C stretches)...

It is common for names of simple heterocyclic carbonyl derivatives to be contracted, with loss of the -ine ending of the parent name, e.g. pyridone, quinolone, acridone, pyrrolidone, thiazolidone. 

The a-oxoketene dithioacetal 6.40 is derived from indoxyl (l,2-dihydroindol-3-one), a heterocyclic carbonyl precursor, and its reaction with simple allyl anions will also yield the corresponding Jl-annulation product. Thus when 6.40 was reacted with allyl anions 65 the corresponding carbinol acetals 66 formed insitu underwent smooth BF3.Et20 assisted cyclization to afford the corresponding carbazoles 67 in high yields <99T11563>. 

Also in the (R)-class of Hnls, although of more limited application, is the (R)-mandelonitrile lyase from Phlebodium aureum [35] which catalyses the addition to some aromatic and heterocyclic carbonyls but only poorly to aliphatic carbonyls. 

The configuration of rhenium(I) requires ligand systems which are able to accept electron density from the electron-rich metal center. Thus, frequently phosphines, nitrogen heterocycles, carbonyls, or isocyanides are encountered. Most of the octahedral products possess a high thermodynamic stability and kinetic inertness as is expected for 18-electron systems. 

Another cyclic thiourea—4,5-dihydrothiazole-2-ylamine 67—reacted with unsaturated heterocyclic carbonyls 68, yielding tricyclic compounds 69 [71] (Scheme 3.21). 

Cyclomethine Dyes can be prepared by condensing N-heterocyclic carbonyl compounds with secondary amines. Intensely colored products such as 4 are obtained by condensing 3-phenylpyrazoline with compounds such as /V-cthyl-naphtholactam. This compound dyes polyacrylonitrile a brilliant, lightfast yellow. Orange-red dyes are obtained by condensing acridone with secondary amines [6],... 

Various types of structures 895 and 896 were obtained with use of transformation (4.58) applied to iminoalcohol derivatives of heterocyclic carbonyl compounds used as ligands [220,225], The structure of 895 [225] and 896 [220] was proved by x-ray analysis ... 

The purpose of this work was to correlate catalytic activity with chemical structure for various aromatic and heterocyclic carbonyl compounds. Gel time, gel time as a function of initiator concentration, and gel time as a function of temperature were used to measure catalytic activity for the unsaturated polyester styrene systems used throughout this work. 

Control of carbon versus oxygen acylation of enolate anions of heterocyclic carbonyl derivatives 890PP179. 

In contrast to the alkene theory the predominant mode of oxidation of the alkyl radicals is by oxygen addition and the alkylperoxy radical so formed then undergoes homogeneous intramolecular rearrangement (reaction (14)). Decomposition of the rearranged radical (reaction (16)) usually leads to a hydroxyl radical and stable products which include O-heterocycles, carbonyl compounds and alcohols with rearranged carbon skeletons relative to the fuel and alkenes. The chain-cycle is then completed by unselective attack on the fuel by the hydroxyl radical (reaction (12)). 

A variety of methods are available for the synthesis of heterocyclic carbonyl compounds by radical cyclization. For example, the cyclization of alkoxycarbonyl radicals is particularly useful for the synthesis of five- and six-membered ring lactones [80]. Recent applications of this cyclization method include Zard s photoly-tical transformation of an alkoxycarbonyl dithiocarbonate having a double bond which can serve as a key step in the synthesis of ( )-cinnamolide and RA. Evans s enantioselective synthesis of 4-hydroxy butenolide terminus, which is applicable to the synthesis of mucocin [81J. Amidyl radical cyclizations are frequently utilized for the synthesis of five- and six-membered ring lactams [82]. However, this section only focuses on recent methods for heterocyclic carbonyl compounds by an n-i-1 type strategy based on radical carbonylations. 

Representative examples of Pd-catalyzed heterocycle carbonylation reactions are shown below. Alkoxycarbonylation of 2,3-dichloro-5-(methoxymethyl)pyridine (79) took place regioselectively at C(2) to give ester 80 [79]. Aminocarbonylation of 2,5-dibromo-3-methylpyridine also proceeded preferentially at C(2) to give amide 81 despite the steric hindrance of the 3-methyl group [80]. 

Heterocyclic carbonyl compounds, synthesis of 81WCH231 79S633. 

Rotational isomerism of five-membered heterocyclic carbonyl compounds ... 

Ohler, E., El-Badawi, M., and Zbiral, E., Dialkyl (l,2-epoxy-3-oxoalkyl)phosphonates as synthons for heterocyclic carbonyl compounds. Synthesis of acyl-substituted thiazoles, indolizines, imidazo[ 1,2-fii]pyridines and imidazo[l,2-fii]pyrimidines, Chem. Ber., 118, 4099, 1985. 

Ring closure by reaction between an amino and a fluoro function is a frequently used method (see Chapter 9) it is sometimes convenient to use a heterocyclic carbonyl group as a precursor of the amine, and thus reduce the number of compounds that have to be isolated and purified in a multistep synthesis. Pyrimidinediones are susceptible to this type of conversion as is demonstrated in the synthesis of a diaza-acridinone. 

It is well established that in a nonpolar solvent, So-> (> ) transitions of heterocyclic carbonyl groups are blue shifted (because of intramolecular hydrogen bonding) and are hence partially hidden by the stronger Sq-> (ti, n ) absorption. This phenomenon is also observed in the case of (19) and... 

Firmenich R., G., R-E. and F-H. (Firmenich Cie) (1969k) Heterocyclic carbonyl compounds (furanes, pyrroles, thiazoles). Br. Patent 1156478. 

Catalytic hydrogenation is commonly used for the reduction of alkenes, alkynes, aromatic hydrocarbons, and aromatic heterocycles, carbonyl derivatives, nitriles, and nitro compounds. The reaction with alkenes proceeds on the surface of a heterogeneous metal catalyst, via cleavage of diatomic hydrogen and adsorption... 

Residue functionality Heterocyclic, phosphoesteric Amino, carboxyl, hydroxy, phenolic thiol, aromatic, heterocyclic Carbonyl, hydroxy, amino, carboxylic... 

The research focus of the Coates Group is the development of new catalysts for the synthesis of macromolecules as well as small molecules. Professor Coates research concentrates on developing new methods for reacting commodity feedstocks in unprecedented ways. His current research centers on the development of homogeneous catalysts for olefin polymerization, heterocycle carbonylation, epoxide homo- and copolymerization, and utilization of carbon dioxide in polymer synthesis. 

CFaiN RfCOF + hvRr + COF Rr + CFjiN- -> RpN CFj. Extension of this to the bis-acyl fluorides FOC (CF2)3-COF and FOC-(CF2>4-COF, however, gives low yields of perfluoro-(Af-methylpyirolid-2-one) (15 %) and perfluoro-(A -methylplperidin-2-one) ca. 10%), respectively, instead of the imines CFg N-(CF2) N CF2 (a = 3 or 4), presumably via the sequence of events shown in Scheme 39. Fluoride-initiated (CsF) reactions between the formaldazine and these, and other, acyl fluorides leads to novel heterocyclic carbonyl compounds which suffer decarbonylation when irradiated with u.v. light (see Scheme 40). Carbonyl fluoride and oxalyl fluoride react with the formaldazine in the presence of caesium fluoride to yield the acylic and cyclic product (57) (70%) and (58) (ca. 55%), respectively the latter fragments to trifluoromethyl isocyanate when exposed to u.v. light. 

Note that in the macrocyclic systems derived from heterocyclic carbonyl compounds and primary diamines, C=N bonds are situated in cis positions with respect to donor atoms (N or X) [200, 201]. In the light of this it becomes obvious that thiophenedialdehyde, which exists in solution in the c,c conformation, is the most suitable with which to form macrocycles. In the cases of other heterocyclic dialdehydes the required c,c conformation is achieved on coordination to a template centre. 

The catalytic carbonylation of allenes can be employed for the synthesis of heterocyclic carbonyl compounds, as shown in Scheme 11.10 [13], which may proceed through oxidative addition of -SH (not Ar-I) to Pd and the following hydropalladation of allene. 

Several papers have been devoted to the oximes of heterocyclic carbonyl compounds [82-84, 86-89], e.g., to the oximes of nitropyr-role-2-aldehydes [82], and formylpyridines [83, 84]. The three isomeric oximes of formylpyridines [84] give one irreversible four-electron wave for the protonated form which decreases at pH > 10. 

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