Naphthoquinone Imine

O-" naphthoquinone imine 1 benzalaniline, phenyl-glyoxylic acid imine, sali-cylaldoxime, benzo-phenone hydrazone, benz-hydrazidine... 

An aq. soln. of Na-)5-naphthoquinone-4-sulfonate refluxed 10 min. with p-ethoxy-aniline in alcohol, and the product isolated after several hrs. -> N-(4-ethoxy-phenyl) -2-hydroxy-a-naphthoquinone imine. Y 90%. F. e. s. I. Oeriu and M. Cracea, >K. S3, 1127 (1963) G. A. 59, 12803d. 

A-(4 -Dimethylaminophenyl)-1,4-naphthoquinone imine, D-00820 5-[(4-Dimethylamino)phenyl]-2,4-pentadienal, D-00821... 

The chemistry of azaquinones centers around the electron-deficient imine double bond. For example, water, methanol, ammonia, methyl-amine, nitromethane, m-xylene, and enamines all add readily to the imine double bond in aza-3-phenyl-l, 4-naphthoquinone. On the other hand azaquinones are also potent dienophiles and thus can function as starting materials for a large variety of highly substituted new heterocyclic compounds. 

Dinitronaphthalene could be expected from the coulometric data [110] to undergo ring closure on reduction, but suitable conditions have not been found yet. The diamine [111] and 8-amino-5-hydroxy-l,4-naphthoquinone-1-imine [112] have been reported as products. 

Benzenesulfonic acid, 882 Benzenesulfonic anhydride, 46 Benzenesnlfonyl chloride, 46-48, 867, 1280 Benzenesulfonyl esters, 47 Benzenesnlfonyl isocyanate, 48 N-Benzenesulfonyl-1,4-naphthoquinone-4-imine, 559... 

Miscellaneous oxidations. Lead tetraacetate in acetic acid at 35° oxidizes 1-benzenesulfonamidonaphthalene (1) to N-benzenesulfonyl-l,4-naphthoquinone-4-imine (2) and it oxidizes 2-benezenesulfonanudonaphthalene (3) to 2-benzene-sulfonamido-1,4-naphthoquinone (4). ... 

In general, the reaction of heteroaromatic JV-imines with a,/ -unsaturated carbonyl compounds gives cycloaddition products as described later (Section IV,C). However, in some cases they can act as nucleophiles. Thus, pyridine N-ethoxycarbonylimine, in the presence of silicic acid, reacts with fumarate, maleic anhydride, (V-phenylmaleimide, p-benzoquinone, and a-naphthoquinone to give the corresponding enamines in good yields (Eq. 23).176 Pyridine JV-imine also reacts with dimethyl maleate to give dimethyl aminofumarate.164... 

This group " also diverted the usual Diels-Alder cycloaddition pathway of Reissert salts with olefinic esters to a 1,3-dipolar cycloaddition pathway by the addition of triethylamine. Thus treatment of munchnone imine 364 with ethyl acrylate and triethylamine affords the 1,3-dipolar cycloaddition product 366 (30%) as the major product, formed by fragmentation of cycloadduct 365 (Fig. 4.121). The Diels-Alder product (not shown) is formed in 15% yield. Similar products to 366 are formed with dimethyl and diethyl maleate and fumarate. Laude and coworkers " also were able to trap munchnone imine 367 with dipolarophiles to furnish 368 (Fig. 4.122). No Diels-Alder cycloadducts derived from the oxazolium salt were detected. In contrast, fumarate and acrylate esters give only Diels-Alder cycloadducts from the tautomeric oxazolium salt (not shown). However, benzo-quinones and 1,4-naphthoquinone react in a 1,3-dipolar fashion with munchnone imine 372 derived from Reissert compound 369 to give 373 (Scheme 4.11). " Diels-Alder cycloadducts derived from oxazolium salt 371 were not observed. In a... 

Lately, Soliman et al. [67] replaced isocyanates in the above reactions by the monoanils of benzil (90), o-naphthoquinone or triketones (such as 91) only to obtain the corresponding azetidinones (92, 93) with each of ylides 2, 82 or 88 (Scheme 19). However, reactions were not run at 2 1 (imine ylide) stoichiometry. 

Keywords Bioorthogonal reaction Photo-triggered reaction Photoclick Tetrazole Nitrile imine Azirine Cyclopropenone o-Naphthoquinone methide o-Quinodimethanes Hetero Diels-Alder reaction... 

The choice of the most effective catalyst system is highly dependent on the type of olefin under consideration. Polymerization of CO and aliphatic a-olefines is most suitably carried out employing a catalytic system modified with a symmetrical, Cs-bridged aryldiphosphine ligand (2,71). However, these systems are not suitable for copolymerization of CO and styrene (41). For this reaction palladium(II)-based catalysts modified with a conjugated diimine (39,41), a bisoxazoline (43,44), a phosphine-phosphite (43), or a phosphine-imine ligand (43) have been employed, in, under chain-transfer conditions, combination with an oxidant promotor, such as 1,4-benzoquinone or 1,4-naphthoquinone (39-47,72), or a polar, acidic type of solvent (73,74). 

With regard to the mechanism, it was assumed that the reaction of diphenylprolinol ether 128 with o(,P-unsaturated aldehyde resulted in an intermediary imininm ion (Scheme 1.83). Subsequent 1,4-addition of 2-hydroxy-l,4-naphthoquinone 189 to imin-ium ion followed by isomoizalion gives rise to the adduct 191. Alia-hydrolysis, acetyliza-tion yields the desired l,4-ni5)hthoquinones 190 with regeneration of the catalyst... 

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