2- Methoxy-3-methyl-1,4-benzoquinone

Zheng, Z., Dutton, P.L. and Gunner, M.R. (2010) The measured and calculated affinity of methyl- and methoxy-substituted benzoquinones for the Q(A) site of bacterial reaction centers. Proteins Struct. Fund. Bioinform., 78 (12), 2638-2654. 

Fumigatin [484-89-9] (3-hydroxy-2-methoxy-5-methyl-/>-benzoquinone) is isolated from metabolism of Aspergillusjumigatus and is used as an antimicrobial. 5-Allyl-l,6-dimethoxy-2,3-methylenedioxybenzene (dillapiole) (62) is a synergist for pyrethrum. Derivatives have been prepared and evaluated (216). 

A related example with 2-methoxy-6-methyl-benzoquinone and penta-l,3-dien-5-ol has been reported Gras, J.-L. Tetrahedron Lett. 1977, 4117... 

Benzoquinone, which also may be employed as retarder (used as stabilizer for methyl methacrylate), gives a phenoxy radical as a result of a rapid addition of the radicals present in the system to the C=0 double bond. The addition is facilitated by aromatic stabilization (452-454). The relative reactivities of alkyl- and methoxy-substituted benzoquinones have been correlated to their redox potentials and steric factors of the substituents (455,456). Industrially, hydroquinone is often added to monomers, although hydroquinone itself acts neither as an inhibitor nor as a retarding agent. However, if oxygen or peroxides are present in the system, the hydroquinone will be oxidized to quinone. Hydoquinone therefore acts in two ways it reduces the peroxides that may initiate the polymerization and acts as an inhibitor in its oxidized quinone form. 

Chemical Name 2,5-Bis(1 -azlridinyl)-3-(1 -methoxy-2-carbamoyloxyethyl)-6-methyl-1,4-benzoquinone... 

In 10 ml of ethanol was dissolved with heating 200 mg of 2-methyl-6-(1-methoxy-2-carba-moyloxyethyl)-1,4-benzoquinone and the resulting solution was cooled. To the cooled solution was added 0.5 ml of aziridine and then the resulting mixture was allowed to stand In a refrigerator at 5°C to 8°C for 4 days. Thereafter, the crystalline substance which precipitated in situ was recovered by filtration and washed with ethanol to give 50 mg of the desired product as red crystals melting at 200°C (with decomposition). 

In a search for allelopathic agents from common weeds, Amaranthus palmerl S. Wats (Palmer amaranth) and Ambrosia artemisiifolia L. (Louisiana annual ragweed) have been analysed for their organic natural products. From A. palmerl phytol, chondrlllasterol, vanillin, 3-methoxy-4-hydroxynitrobenzene and 2,6-dimethoxy- benzoquinone were isolated. From the roots of Ambrosia artemisiifolia four polyacetylenes, a mixture of sesquiterpene hydrocarbons, methyl caffeate, and a mixture of 8-sitosterol and stlgmasterol were obtained. 

Addition of the arylamines 117 to 2-methoxy-3-methyl-l,4-benzoquinone 118 affords regioselectively the 5-arylamino-2-methoxy-3-methyl-l,4-benzo-quinones 119 (Scheme 37). Palladium(II)-catalyzed oxidative cyclization leads to the carbazole-l,4-quinones 28 [135,136],previously obtained by the iron-mediated approach (cf. Scheme 14). Regioselective addition of methyllithium to the quinones 28 provides carbazomycin G 29a and carbazomycin H 29b [96,135]. Reduction of 29a with lithium aluminum hydride followed by elimination of water on workup generates carbazomycin B 23a [135]. Addition of heptylmag-... 

Capuchin monkeys (Cebusspp.) in Venezuela self-anoint with a benzoquinone-secreting millipede. Two of the compounds by themselves also release selfanointing. These are 2-methyl-l,4-benzoquinone and 2-methoxy-3-methyl-l,4-benzoquinone. These compounds repel mosquitoes (Valderrama et al, 2000 Weldon etciZ., 2003). 

Furukawa et al. reported the total synthesis of murrayaquinone A (107) by a palladium(II)-mediated oxidative cyclization of the corresponding 2-arylamino-5-methyl-l,4-benzoquinones. 2-Anilino-5-methyl-l,4-benzoquinone (842) was prepared starting from 2-methyl-l,4-benzoquinone 841 and aniline 839, along with the regio-isomeric 2-anilino-6-methyl-l,4-benzoquinone (844). The oxidative cyclization of 2-anilino-5-methyl-l,4-benzoquinone (842) with stoichiometric amounts of palla-dium(ll) acetate provided murrayaquinone A (107) in 64% yield. This method was also applied to the synthesis of 7-methoxy-3-methylcarbazole-l,4-quinone (113) starting from 3-methoxyaniline (840) (623). Seven years later, Chowdhury et al. reported the isolation of 7-methoxy-3-methylcarbazole-l,4-quinone (113) from the stem bark of Murraya koenigii and named it koeniginequinone A (113) (49) (Scheme 5.101). 

Our palladium(II)-catalyzed approach for the carbazomycins G (269) and H (270) requires the carbazole-l,4-quinones 941 and 981 as precursors (compare the iron-mediated synthesis, see Scheme 5.137). These intermediates should result from oxidative cyclization of the arylamino-l,4-benzoquinones, which in turn are prepared from the arylamines 839 and 984 and 2-methoxy-3-methyl-l,4-benzoqui-none (939) (652) (Scheme 5.138). 

One of the carbazole-l,4-quinones, 3-methoxy-2-methylcarbazole-l,4-quinone (941), required for the total synthesis of carbazomycin G (269), was already used as a key intermediate for the total synthesis of carbazoquinocin C, and was obtained by the addition of aniline (839) to 2-methoxy-3-methyl-l,4-benzoquinone (939), followed by oxidative cyclization with catalytic amounts of palladium(II) acetate (545,645) (see Schemes 5.124 and 5.125). Similarly, in a two-pot operation, 4-meth-oxyaniline (984) was transformed to 3,6-dimethoxy-2-methylcarbazole-l,4-quinone... 

Cyclohexadienes are available by the methodology of Birch, and the reactions of l-methoxy-, 1,3-dimethoxy-, l,3-bis(trimethyl-silyloxy)-, and l-methoxy-4-methyl-l,3-cyclohexadiene with a number of 1,4-benzoquinones have been investigated. Acid treatment of the adducts and subsequent dehydrogenation provides a synthesis of 2-dibenzofuranols. Thus the adduct 159 (Scheme 41) from 1,4-benzoquinone and 1,3-dimethoxy-1,3-cyclohexadiene, on treatment with a trace of concentrated hydrochloric acid in ethanol at room temperature, affords the tetrahydrodibenzofuranone 161. When the adduct 159 is heated under reflux in aqueous methanol, the reaction can be arrested at the dihydrodibenzofuran 160. The tetrahydrodibenzofuranone 161 on dehydrogenation with palladized charcoal affords 2,7-dibenzofurandiol. ... 

Treatment of veratrole (191) with excess of 2,5-dichloro- (192) or 2,6-dichloro-1,4-benzoquinone in 70% sulfuric acid yields dibenzofurans and other products. Thus 2,5-dichloro-1,4-benzoquinone (192, Scheme 49) affords the dibenzofuran 193, the diarylquinone 194 and the triphenylene 195. The quinol formed by acid-catalyzed addition of veratrole (191) to the quinone 192 is presumably oxidized to the arylquinone 196, which can form the dibenzofuran 193 or undergo further arylation. The quinone 196 is also available by arylation of 2,5-dichloro-1,4-benzoquinone (192) with 3,4-di-methoxybenzenediazonium chloride in buffered solution. On treatment with 70% sulfuric acid, the arylquinone 196 affords the dibenzofuran 193 (88%). The cyclization can also be effected photochemically. The aryl-quinones available by treatment of 2,5- and 2,6-dichloro-1,4-benzoquinones with buffered solutions of diazotized 4-methoxy-3-methyl- and 3-methoxy-4-methylaniline have been cyclized to 2-dibenzofuranols by the agency of aluminum chloride in hot benzene. ... 

Oxidation of 4-methyl-2-tert-butylphenol (225, Scheme 57) by 2,3-di-chloro-5,6-dicyano-l,4-benzoquinone in methanol affords the dibenzofuran 228. The intermediate oxepinobenzofuran 226, as its valence isomer 227, undergoes nucleophilic attack by methanol and subsequent dienone-benzene rearrangement with the migration of the methoxy group. 

Three of the four possible azepinediones have been isolated from the Schmidt reaction on 2-methoxy-5-methyl-p-benzoquinone 3-methyl-6-methoxy-l//-azepine-2,5-dione is the missing isomer (74CJC3327). 

Lewis acids are frequently employed in catalyzing the Diels-Alder reaction. Particularly fascinating is the observation of the different regiochemistry arising from monodentate and bidentate chelation of 2-methoxy-5-methyl-l,4-benzoquinone with boron trifluoride and stannic chloride, respectively [177],... 

Alkaline hydrolysis of benzal acetone structures to the corresponding aldehyde (XIX) and acetone and subsequent oxidation of the aldehyde (XIX) to the corresponding benzoic acid (V) do not seem to represent an actual degradation stage since oxidizing the aldehyde (XIX) under our mild standard conditions yielded only traces of the corresponding benzoic acid (V). The aldehyde (XIX) was rapidly decomposed via Dakin reaction to formic acid and 3-methoxy-S-methyl-o-benzoquinone, which is immediately degraded to phenolic humic compounds. 

Sodium methylate acting on 2-chloroanthraquinone substitutes the methoxy group for chlorine and produces anion radicals of the substrate (Shtemshis et al. 1973). The study of kinetics has demonstrated that the amount of the substrate anion radical first increases and then sharply decreases. The inhibitor (p-benzoquinone) decelerates the formation of the anion radicals. The rate of formation of 2-methoxyanthraquinone also decreases. If the anion radicals were produced on the side pathway, the rate of formation of the end product upon the introduction of the inhibitor should not have decreased. Moreover, it should even rise, because oxidation of the anion radicals regenerates the uncharged molecules of the substrate. Hence, the anion radical mechanism controls this reaction. 

AT-Formylnor-reticuline, on treatment with 2,3-dichloro-5,6-dicyano-l,4-benzoquinone in methanol, is oxidized to the 4-methoxy-compound (35), which can be cyclized to N-norbisnorargemonine (36) (converted by N- and O-methylation into argemonine) by mineral acid or to the isopavine N-formyl-northalidine (37) by treatment with methanesulphonic acid in acetonitrile. The N-formyl compounds can be reduced to AT-methyl by borane or converted into the secondary bases by hydrazinolysis.69... 

Molecular electrostatic potentials have been used to explain the regioselectivity exhibited in the Diels-Alder cycloaddition reactions between 1-trimethylsilyloxy-butadiene and the quinones 5-formyl-8-methyl-1,4-naphthoquinone, 5-methoxy-7-methyl-1,4-phenanthrenequinone, and 5,6,7-trimethyl-1,4-phenanthrenequinone.128 The intramolecular Diels-Alder reaction of masked o-benzoquinones (123) with a variety of dienes provides adducts (124) which rearrange to functionalized ris-decal ins (125) with complete stereocontrol of up to five stereocentres. This methodology ... 

X- 3-Methoxy-l,2-benzoquinone/Cellulose JK- 4-Methyl-l,2-benzoquinone/Cellulose... 

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