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2- Amino-3-hydroxy 4-naphthoquinone

The shikimate pathway is the major route in the biosynthesis of ubiquinone, menaquinone, phyloquinone, plastoquinone, and various colored naphthoquinones. The early steps of this process are common with the steps involved in the biosynthesis of phenols, flavonoids, and aromatic amino acids. Shikimic acid is formed in several steps from precursors of carbohydrate metabolism. The key intermediate in quinone biosynthesis via the shikimate pathway is the chorismate. In the case of ubiquinones, the chorismate is converted to para-hydoxybenzoate and then, depending on the organism, the process continues with prenylation, decarboxylation, three hydroxy-lations, and three methylation steps. - ... [Pg.102]

Lau and Gompf359 prepared a series of 2-amino-6-hydroxybenzo[d]-thiazoles and corresponding naphtho[l,2-d]thiazoles on treating 1,4-benzoquinone and 1,4-naphthoquinone with thiourea in acidic media at room temperature. At high temperature the products of the reaction with 1,4-benzoquinone are 5-hydroxy benz[d]-l,3-oxathiol-2-ones... [Pg.151]

Bcnzofuran-4,7-dioncs have been synthesized regioselectively by [3 + 2] photoaddition of 2-hydroxy-1,4-benzoquinones with a range of alkenes (equation 185)664. The reaction occurs in 30-60% yield and is a useful method for the synthesis of the benzofuran ring system, which is important in natural products like acamelin665. Substituted naphthoquinones may also be used in this reaction666,667 and this has lead to a very simple two-step synthesis of maturinone. In a similar reaction, a [3 + 2] photoaddition reaction of 2-amino-1,4-naphthoquinones with electron-rich alkenes gave 13-82% yields of 2,3-dihydro-177-bcn/ /]indole-4,9-diones in a single-step process which involved photolysis followed by oxidation (equation 186)668,669. [Pg.757]

Hydroxylated 1,4-benzoquinones and 1,4-naphthoquinones gave similarly the corresponding dipoles [164]. The amino analogs reacted in the same way to afford first isolable iodonium salts and then the imino dipoles (Scheme 54) [165]. It is noted that the open-chain methyl 2-aminocrotonate gave with [hydroxy(tosyloxy)iodo]benzene only the iodonium salt, i.e. -MeC(NH2) = C(COOMe)I+Ph TsO- [166]. [Pg.93]

The more intensely colored 1,4-naphthoquinones with amino and/or hydroxyl groups in the 5- and 8-positions are analogous to the commercial anthraquinone dyes, but are generally more bathochromic [10], For example, 5-methylamino-1,4-naphthoquinone has Xmax 529 nm in cyclohexane, whereas 1-methylaminoanthraquinone has Xmax 495 nm. This is also true for the 5,8-disubstituted naphthoquinones, but this potential advantage has not proved of commercial significance, and few such compounds have been considered as textile dyes. An exception is 5-amino-2,3-dichloro-8-hydroxy-l,4-naphthoquinone (4) [68217-33-4], which has been claimed as a violet disperse dye for acetate fibers [14], Naphthazarin (1) is an example of a 5,8-disubstituted naphthoquinone of greater value as an intermediate than as a dyes. [Pg.331]

To a stirred suspension of 2-amino-1,4-naphthoquinone (173 mg, 1 mmol) in dichloromethane (15 ml) was added [hydroxy(tosyloxy)iodo]benzene (411 mg, 1.05 mmol). After 20 min, the yellow iodonium salt which separated was collected, washed with dichloromethane and dried (520 mg, 95%). This salt (547 mg, 1 mmol) was added to a cold aqueous solution of 2% sodium hydroxide (2 mmol). The mixture was stirred until the yellow colour turned red, about 20 min the precipitate was collected, washed with water and ether and dried to give 2-phenyliodonio-l,4-naphthoquinone-3-imide (263 mg, 70%), m.p. 115-117°C. [Pg.181]

Hydroxy-naphthochinon-( 1,2), 7-Hydroxy-1,2-naphthoquinone). (HO).CioHs (0)2, mw 174.16, OB to CO2 —183.74%, dark red microcrysts, mp 203 —204° (decompn). Sol in ale AcOH. Prepn from l-amino-2,7-dioxy-naphthalene by oxidation with chromic-sulfuric acid Refs 1) Beil 8, 299, (634) 2542 2) S. Mededeco O. Bloch, ChemZtr (1935), 2670... [Pg.204]

It will be recalled that when para-di-hydroxy benzene, hydro-quinol, and also other para di-substitution products of benzene are oxidized there is obtained the compound known as quinone or benzo-quinone (p. 636). In a similar way para di-suhstituied naphthalenesy especially hydroxyl and amino compounds, and in fact naphthalene itself when oxidized with chromic acid, yield a quinone analogous to benzoquinone and which is known as alpha-naphthoquinone. [Pg.790]

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. [Pg.680]

A variety of heterocyclic compounds of the indole and benzofuran type can be made via photoaddition of alkenes to 2-amino- or 2-hydroxy-1,4-naphthoquinone. These products, described by H. Suginome probably derive from an intramolecular trapping reaction of the intermediary 1,4-biradicals or 1,4-zwitterions. [Pg.71]

Unlike in the case of phenols, direct oxidative dimerization of quinones only takes place under drastic conditions and requires a hydroxy or amino group on the quinonoid double bond, as in Lawson 4c, the dye in Arabian henna. Since the work of Pummerer (1937), however, it has been known that monomeric 1,4-quinones can be oligomerized much more easily under acidic or basic conditions. [8] In pyridine/ethanol, or by wanning in glacial acetic acid, we have converted naphthoquinone, 1,4-anthraquinone, and nu-... [Pg.333]

Naphthoquinones (xee Quinones) NmmJES (see also Amino niinles. Cyanohydrins, Hydroxy nitriles)... [Pg.399]

The aza analogues of 417, iodine-nitrogen zwitterions 419, have been prepared by the reaction of 2-amino-1,4-naphthoquinone (418) with [hydroxy(tosyloxy)iodo]arenes (Scheme 2.122) [205,562,563]. Ylides 419 show interesting reactivity upon heating, aryl migration from iodine to nitrogen occurs, giving product 420,... [Pg.102]

Ainino-l 2-naphthoquinone (4-Amino- naphthoquinone, 2-hydroxy-oL-naphtkoquinonim-ine)... [Pg.112]

Dehydroquinic acid, shikimic acid, and chorismic acid are carboxylated compounds containing a six-membered carbocyclic ring with one or two double bonds (Fig. 143). The secondary products derived from these substances either still contain the ring and the C -side chain of the acids (see the structure of the benzoic acid derivatives, of anthranilic and 3-hydroxyanthranilic esters, D 8, D 8.2, D 8.4 and D 8.4.1) or have additional rings (see the formulae of naphthoquinones and anthraquinones, D 8.1, of quinoline, acridine, and benzodiazepine alkaloids, D 8.3.2). The carbon skeletons may be substituted by isoprenoid side chains (see the structure of ubiquinones, D 8.3) and may carry different functional groups, e.g., hydroxy, carboxy, methoxy, and amino groups. [Pg.259]

The [l,4,2]-oxazaphosphinane naphthoquinones 51 were obtained from a short synthesis based on transformation of 2,3-dichloro-l,4-naphthoqui-none into 2-amino-3-hydroxy-1,4-naphthoquinone 50 by a double Michael addition of water and of nitrite, followed by the reduction of the nitro group into an amino group using sodium dithionite (Scheme 11). Then, a three component reaction, mixing various ketones, alkyl dichloro-phosphate, and quinone 50 furnished fused the quinonic systems 51 in yields ranging from 60% to 95%. The monoester derivative 52 is readily obtained by treatment of the ester 51 ((R = Et, = R = Me) with TMSBr in chloroform, followed by methanolysis of the sdyl ester intermediate. [Pg.145]

Vitamin K3 (menadione, MK-0,2-methyl-1,4-naphthoquinone) is a synthetic substance. The product of menadione reduction, known as menadiol (2-methylnaphthalene-l,4-diol), and derived compounds, such as the fat-soluble menadiol diacetate or menadiol dibutyrate and the water-soluble sodium salt of menadiol diphosphate, are referred to as vitamin K4. Activity of vitamin K was also detected in the synthetic monoamino analogues and diamino analogues of menadiol, for example, in l-amino-4-hydroxy-3-methylnaphthalene (vitamin K5), l,4-diamino-2-methylnaphthalene (vitamin Kg) and l-amino-4-hydroxy-2-methylnaphthalene (vitamin K ). [Pg.369]

Kobayashi, K., Uchida, M., Watanabe, S Takanohashi, A., Tanmatsu, M., Morikawa, O., and Konishi, H., Synthesis of 1-amino and l-hydroxy-9,10-anthraquinone derivatives based on reaction sequences between 2-acetyl-l,4-naphthoquinone and enamines. Tetrahedron Lett., 41, 2381-2384, 2000. [Pg.1801]

Amino-4,6-dimethylphenol and 2-hydroxy-1,4-naphthoquinone heated 90 min. at 100° in glacial acetic acid 6,8-dimethyl-3,4-benzo-2-phenoxazone. Y 97%. —The yield decreases and the formation of anilinoquinones increases if less basic o-aminophenols are used. F. e. s. A. Butenandt, E. Biekert, and W. Schafer, A. 632, 134 (1960). [Pg.119]


See other pages where 2- Amino-3-hydroxy 4-naphthoquinone is mentioned: [Pg.203]    [Pg.194]    [Pg.195]    [Pg.84]    [Pg.249]    [Pg.326]    [Pg.50]    [Pg.77]    [Pg.121]    [Pg.198]    [Pg.169]    [Pg.332]    [Pg.77]    [Pg.121]    [Pg.113]    [Pg.231]    [Pg.45]    [Pg.261]    [Pg.95]    [Pg.206]    [Pg.79]    [Pg.80]    [Pg.1789]    [Pg.1747]   
See also in sourсe #XX -- [ Pg.145 ]




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1 : 4-Naphthoquinone

Amino hydroxy

Naphthoquinone 2-amino

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