Methyl-methoxy-naphthoquinone

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 ... 

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. 

Diel -AldeT catalyst. Kelly and Montury have examined the effect of three Lewis acids on the Diels-Alder reaction of perf-hydroxylated naphthoquinones with l-methoxy-3-methyl-l,3-butadiene magnesium iodide, boron trifluoride etherate, and boron triacetate. All three increase regioselectivity. BF, etherate and B(OAc)3... 

The analogue of 1 hydroxylated at C-6, e.g. 3-deoxyrabelomycin (20), was synthesized by Kraus and Wu using the excellent Michael acceptor properties of the extremely electron-deficient 3-acetyl-5-methoxy-1,4-naphthoquinone (17) [31, 32] (for related reactions of Eugster et al. compare [33]). The addition of 5-methyl-l,3-cyclohexadione (18) proceeded at 20-25 C without catalyst to afford adduct 19 after methylation. The subsequent intramolecular Michael-type reaction followed by elimination of methanol afforded more drastic conditions (NaOH, MeOH, 140 °C) and gave relatively low yields (27%) of a tetracyclic intermediate which was demethylated in the usual manner with AICI3 to yield 3-deoxyrabelomycin (20, Scheme 6). 

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. 

Prekinamycin (35), like kinamycins A-F, was isolated from Streptomyces murayamaensis. Carbazole 33, a regioisomer of 7-deoxyprekinamycin (34), was synthesized in only four steps utilizing Pd(OAc), promoted oxidative cyclization as the pivotal step [27]. Similar to Furukawa s approach, the anilino-l,4-naphthoquinone 32 was obtained via Michael addition of the corresponding 2-methoxy-4-methyl-aniline to 1,4-naphthoquinone. Oxidative cyclization proceeded in 84% yield. 

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-... 

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). 

Javanicin, 5,8-Dihydroxy-6-methoxy-2-methyi-3-(2-oxopropyt)-I,4-naphthalenedione 3-acetonyi-5,8-dihydr-oxy-6-methoxy-2-methyl-1,4-naphthoquinone. C,(H,4Ot ... 

However, oxidation of 2-naphthol methyl ether (nerolin) leads to a quinone, namely, 4-(2 -methoxy-l -naphthyl)-1,2-naphthoquinone. 

An ethereal soln. of 4-methoxy-2-methyl-3-(2-methyl-l-propenyl)-l-naphthyl piva-late added dropwise to LiAlH4 in ether, refluxed 1 hr., the intermediate 4-methoxy-1-naphthol dissolved in aq. 50%-acetonitrile, treated with a soln. of FeClg in the same solvent mixture, and stirred 15 min. -> 2-methyl-3-(2-methyl-l-propenyl)-1,4-naphthoquinone. Y 88%. F. e., also oxidation in ether-ethanol-water, s. W. E. Bondinell et al., J. Org. Chem. 33, 4351 (1968). 

Me ether [39058-18-9]. 5-Hydroxy-2-methoxy-7-methyl-1,4-naphthoquinone C12H10O4 M 218.209... 

Acetyl-2-hydroxy-8-methoxy-6-methyl-1,4-naphthoquinone, in A-10017 1 -(3,4-Dihydroxyphenyl)-1 -(2,4,6-trihydroxyphenyl)ethylene, D-20176 Orientalone, in A-10017 Pratenol A, P-20136... 

Geranyloxy-5-hydroxy-7-methoxy-6-methyl-1,4-naphthoquinone, in T-10164 Glyasperin D, in T-10068 Glyasperin I, in T-10068 Kanzonol R, in T-30076 Wallichinin, W-20001... 

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