2-Methoxy-l,4 naphthoquinone

Wang YC, Li WY, Wu DC, Wang JJ, Wu CH, Liao JJ, Lin CK. (2009) In vitro activity of 2-methoxy-l, 4-naphthoquinone and stigmasta-7,22-diene-3P-ol from Impatiens balsamina L. against multiple antibiotic-resistant Helicobacter pylori. Evid Based Complement. Alternat Med 9 1-8. 

N.A. Balsaminones, 2-methoxy-l, 4-naphthoquinone, saponins, quercitin, kaempferol derivatives, balsaminasterol, parinaric acid, hosenkosides.302 Remedy for rashes, pain caused by insect bites, anti-inflammation. 

Phytochemistry Aboveground parts contained flavonoid glycosides (0.43 %), alkaloids (0.016 %), resins (3.53 %), vitamin C (7.2 mg%), and traces of carotene. The compounds N-oxy-benzoic acid, vaniUic, gentisinic, ferulic acid, N-coumarinic and caffeic acids, as well as 2-methoxy-l,4 naphthoquinone have been isolated from the leaves (Khalmatov 1964). Oil from the seeds contains parinaric acid (Tsevegsuren et al. 1998). 

In the case of the addition of />-nitroaniline to 1,4-naphthoquinone, or the replacement of the methoxy group in 2-methoxy-l,4-naphthoquinone, the catalytic effect was ascribed to coordination of cerium to a carbonyl group. 

Nucleophilic Substitution Reactions. Many of the transformations reali2ed through Michael additions to quiaones can also be achieved usiag nucleophilic substitution chemistry. In some iastances the stereoselectivity can be markedly improved ia this fashion (100), eg, ia the reaction of ben2enethiol with esters (R = CH C O) and ethers (R = 3) 1,4-naphthoquiaones. 2-Bromo-5-acetyloxy-l,4-naphthoquiQone [77189-69-6J, R = Br, yields 75% of 2-thiophenyl-5-acetyloxy-l,4-naphthoquinone [71700-93-1], R = SC H. 3-Bromo-5-methoxy-1,4-naphthoquinone [69833-10-9], R = Br, yields 82% of 3-thiophenyl-5-methoxy-l,4-naphthoquinone [112740-62-2] R = SC H. ... 

Identical kinetics are exhibited in the analogous oxidations of 1- and 2-methoxynaphthalene to 4-methoxyl-l-naphthyl acetate and 2-methoxy-1,4-naphthoquinone respectively . In these cases the radical-cations may react with acetate ion thus... 

Fig. 10. The structures of 2-methoxy-1,4-naphthoquinone and stigmasta-7,22-diene-3P-ol (spinasterol) with anti-HP activities, isolated from Impatiens balsamina L.

Phenoxazin-3-ones and phenothiazin-3-ones can be prepared by the oxidation of the parent heterocycles in acidic media, but it is often more practical to employ condensation reactions between 2-amino-phenols or -thiols and quinones. Alizarin Green G (263), for example, is obtained from the aminophenol (261) and the 1,2-naphthoquinone (262). Similarly, 2-aminothiophenols (264) and 6-chloro-2-methoxy-l,4-benzoquinone (265) afford phenothiazin-3-ones (266) bearing methoxyl groups at position 1. 

Another substitution reaction that is initiated by photochemical hydrogen abstraction is the replacement of the bromine atom in 2-bromo-8-methoxy-l, 4-naphthoquinone by an acyl group757. Irradiation of a solution in benzene of the quinone, butyraldehyde or capraldehyde and pyridine yields mixtures of acylated quinone and acylated hydro-quinone. In the first step, the excited quinone abstracts the aldehyde hydrogen atom and this is followed by bond formation between the acyl radical and C-2 of the quinone. The radical that is formed after departure of a bromine atom may either lose a hydrogen atom and yield acylated quinone or take up a hydrogen atom and become acylated hydro-quinone. 

Recovered starting material (N-[2-methoxy-4-methylphenyl]-2-amino-l,4-naphthoquinone). Isolated yield of 4-methoxy-2-methyl-5H-benzo[l)]carbazole-6,ll-dione. 

The reaction of diazo(trimethylsilyl)methane (1) with quinones leads mainly to indazoles, the products of a [3 + 2] cycloaddition between the diazo function and a C-C double bond followed by desilylation and oxidation.In contrast, 2-methyl-l,4-naphthoquinone and 2-methoxy-1,4-naphthoquinone require higher reaction temperatures, and no trace of a heterocyclic compound can be detected, rather the trimethylsilyl-substituted cyclopropanes 5 are formed as a mixture of diastereomers. 

Isochromans. - The antibiotic ( )-nanaomycin A (111) has been synthesized by two routes from 2-bromo-8-methoxy-l,4-naphthoquinone. Readily accesssible indanones have been converted into isochromans, which have been elaborated into 9-demethoxyeleutherin (112) and 9-deoxynanaomycin A methyl ester (113). Some pharmacological interest has appeared in l-(piper-... 

Cultured plant cells may also serve as sources of various naphthoquinones and benzoquinones, whether or not they are present in the whole plants. For example, suspension cultures of Panax ginseng C. A. Meyer were treated with either an elicitor preparation from the phytopathogenic Botrytis cinerea or a yeast elicitor preparation, and the accumulation of a new compound (2,5-dimethoxy-l,4-benzoquinone), which was not detected in non-elicited cultures, was observed [345], Induction of naphthoquinone formation in Impatients balsamina cell cultures was achieved by using parent plants yielding high levels of 2-methoxy- 1,4-naphthoquinone as initiated explants. The cell cultures were capable of producing two naphthoquinones, lawsone... 

Fusarubin. 374-Dihydro-3,6,9-trihydroxy-7-nietti-oxy-i-metbyi-1 H-nophtho 2,3-cjpyran-5,10-diune 5,8-di-h ydroxy-2-hydroxy-methyl)-6-methoxy-l, 4-naphthoquinone oxyjavanicin. C HmO, mol wt 306.26. C 58.82%, H 4.61%, O 36.57%. 1 solti from Fusarium solani Ruelius, Gauhe, Ann. 569, 38 (]950). Structure Hardegger et al. Helv. Chim. Acta 47, 2027 (1964). Efficient total synthesis Y, Tanoue ei al. Bull Chem. Soc. 60, 2927 (1987). 

Kinetic and thermodynamic control. Phosphoric and formic acids (1 1) added to a soln. of 2-jd-hydroxypropyl-5-methoxy-l,4-naphthoquinone (prepn. s. 158) in acetaldehyde and some acetone, allowed to stand 24 hrs. at 20° -> mixture of 89-94% ( )-eleutherin and 6-11% ( )-isoeleutherin. Y 69%.—Kinetic control gives mostly ( )-eleutherin whereas thermodynamic control (s. original) gives a larger amount of ( )-isoeleutherin. W. Eisenhuth and H. Schmid, Helv. 41, 2021 (1958). 

A different class of polycyclic naphthoquinone dyes is based on the n apht h 12,361 i ndolizine -6,11 -dione system 14, which is readily accessible by condensation of 2,3-dichloro-l,4-naphthoquinone with active methylene compounds in the presence of pyridine [22], or by reaction of 2-methoxy-3-pyridino-1,4-naphthoquinone with an active methylene compound [23], In 14, the bridgehead nitrogen atom acts as an effective auxochrome, and hence orange to red colors are observed without further substitution. Derivatives of 14 (R = amide group) are of particular value as vat dyes and pigments. Related isomeric heterocyclic structures have also attracted interest, e.g., 15, a yellow disperse dye for polyester [24],... 

Many synthetic applications have been reported of the photochemical reactions of halogen-substituted 1,4-naphthoquinones with 1,1-diarylethenes487 90, and with related electron-rich alkenes such as 1-aryl-l-trimethylsilyloxyethenes491 93, 2-trimethylsilyloxy-1-alkenes494, 2-methoxy-l-alkenes495 and allyltributylstannane496,497. The process is exemplified by the reaction of 2-bromo-3-methoxy-1,4-naphthoquinone derivatives (152) with 1,1-diphenylethene487 (equation 129). 

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