Unsaturated aromatic amides

On the other hand, a slight modification of the latter reaction protocol can be employed for the synthesis of o -bromo- -lactams when the starting material is a a. -unsaturated aromatic amide, with catalysis by NaOAc instead of LiOAc (eq 33). ... 

The only other type noted concerned the photocyclization of the unsaturated pyrazine amide (425) to (426) with subsequent selenium dioxide aromatization (72CPB2264). 

This procedure illustrates a general method for preparing aliphatic and, in certain cases, aromatic /3-lactarns containing a free NH group and substituted in either the 4 position or in both the-3 and 4 positions of the 2-azetidinone ring. The major byproduct of the cycloaddition step is a /3,7-unsaturated carbox-amide-N-sulfonyl chloride which, in the case of certain aromatic olefins, may predominate. Reactions of both /3-lactam-N-sulfonyl chlorides and the /3,y-unsaturated carboxamide-N-sulfonyl chlorides have been tabulated.3... 

Many of the known examples involve base-promoted carbanion formation from aromatic amides. For example, indol-2-one derivatives 161 have been made by treatment of N-acyl-o-haloanilines 160 with LDA in THF, or KNH2 in liquid ammonia [132-134] (Scheme 35). Similarly, a,P-unsaturated anilides 162 afford the ring-closed 3-alkylideneoxindoles 163 on irradiation and treat-... 

A few diamides have been converted to diamines. For the most part, the conversion of unsaturated amides is unsatisfactory however, a-allylphenylacetamide is transformed to a-allylbenzylamine in a 90% yield. Aromatic amides having free or methylated phenolic groups are treated preferably with sodium hypochlorite rather than hypobromite in order to avoid excessive ring halogenation. Certain amino acids like anthranilic acid and /3-alanine have been synthesized from the appropriate imides. ... 

There are a few efficient methods for the stereoselective synthesis of vinyl halides, and this transformation remains a synthetic challenge. Research by S. Roy showed that the Hunsdiecker reaction can be made metal free and catalytic catalytic Hunsdiecker reaction) and can be used to prepare ( )-vinyl halides from aromatic a,p-unsaturated carboxylic acids. The unsaturated aromatic acids were mixed with catalytic amounts of TBATFA and the A/-halo-succinimide was added in portions over time at ambient temperature. The yields are good to excellent even for activated aromatic rings which do not undergo the classical Hunsdiecker reaction. The fastest halodecarboxylation occurs with NBS, but NCS and NIS are considerably slower. The nature of the applied solvents is absolutely critical, and DCE proved to be the best. This strategy was extended and applied in the form of a one-pot tandem Hunsdiecker reaction-Heck coupling to prepare aryl substituted (2 ,4 )-dienoic acids, esters, and amides. 

A minimum of three chiral constraints are used to maintain planarity at unsaturated bonds (aromatic, amide, ester, etc.) atoms 1-2-3-4, 1-5-6-3, and... 

Recently, Rouquet and Chatani reported a ruthenium-catalysed ortho-C-H alkylation of aromatic amides by 1,4-addition to various a,p-unsaturated ketones with the aid of a removable bidentate directing group, 8-aminoquinoline. For this approach RuCl2(PPh3)3 and NaOAc in toluene at 100 °C were employed. Both electron-rich and electron-deficient amides were monoallq lated with a variety of allq l and aryl enones. 

The products, obtained from the cycloaddition of chlorocarbonyl ketenes 126 with N-unsubstituted a, 8-unsaturated amides or aromatic amides are quite different from the those obtained from the cycloaddition of... 

The chemical resistance of polyester amide glass fibre composite is excellent [126]. A solvent mixture of CF3COOH/CHCI3 was used as a solvent for thermotropic LC polyester, based on 4-chlorocarbonyl phenyl esters of aromatic dicarboxylic acids and phenols or aliphatic diols for viscosity measurement. This indicates thermal stability in various organic solvents. [127]. Unsaturated aromatic LC polyesters, synthesized with the aim to fix the LC state, can be crosslinked by using styrene. The crosslinked matrix can be degraded by refluxing in 3 M aqueous sodium hydroxide solution and methanol in a vol. ratio of 3 2 [128]. 

Unsaturated N,N-dialkylamides and aromatic amides, such as benz-amide, do not react to give imides. 

A series of cross-linkable copoly(amide—imides) is known to be possible from aromatic diamines and substituted isophthaloyl chlorides containing unsaturated imide rings as a pendent function (13). 

Although fluorocarbons are considered very stable compounds, they can be defluonnated to unsaturated denvatives under certain mild conditions. Hexa-decafluorobicyclo[4.4.0]dec-I(6)-ene reacts with activated zinc powder at 80-100 °C to yield partially and fully aromatized products [61] The final product composition depends on the solvent. Dioxane, acetonitrile, and dimethylform-amide, m this order, effect increasing unsaturation (equation 30). 

The chemistry of indium metal is the subject of current investigation, especially since the reactions induced by it can be performed in aqueous solution.15 The selective reductions of ethyl 4-nitrobenzoate (entry 1), 2-nitrobenzyl alcohol (entry 2), l-bromo-4-nitrobenzene (entry 3), 4-nitrocinnamyl alcohol (entry 4), 4-nitrobenzonitrile (entry 5), 4-nitrobenzamide (entry 6), 4-nitroanisole (entry 7), and 2-nitrofluorenone (entry 8) with indium metal in the presence of ammonium chloride using aqueous ethanol were performed and the corresponding amines were produced in good yield. These results indicate a useful selectivity in the reduction procedure. For example, ester, nitrile, bromo, amide, benzylic ketone, benzylic alcohol, aromatic ether, and unsaturated bonds remained unaffected during this transformation. Many of the previous methods produce a mixture of compounds. Other metals like zinc, tin, and iron usually require acid-catalysts for the activation process, with resultant problems of waste disposal. 

This section contains dehydrogenations to form alkenes and unsaturated ketones, esters and amides. It also includes the conversion of aromatic rings to alkenes. Reduction of aryls to dienes is found in Section 377 (Alkene-Alkene). Hydrogenation of aryls to alkanes and dehydrogenations to form aryls are included in Section 74 (Alkyls from Alkenes). 

Prasad and Joshi121 presented a conceptually different catalyst system—zinc amides of oxazolidine. Because the addition of dialkylzinc to aldehyde is known to involve a chiral zinc alkoxide with a coordinately unsaturated tricoordinated center, they anticipated that a zinc amide with dicoordinate zinc should be a better Lewis acid. Examining three different zinc species 128-130, zinc amide derived from the corresponding oxazolidine 130 was found to lead to a very fast reaction (4 hours, 0°C) and 100% ee (Scheme 2-50). The reaction proceeds even faster at room temperature (completed within 1 hour) without significant loss of stereoselectivity. This reaction can provide excellent ee for aromatic aldehydes,... 

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