6-Methyl-1,4-naphthoquinone

Vitamin K — Fat-soluble vitamin K is a group name for fat-soluble compounds which have in common a methylated naphthoquinone ring structure. Vitamin K is found in nature in two forms - Ki or phylloquinone is found in plants and vitamin K2 or menaquinone can be synthesized by many bacteria. Vitamin K3 (menadione) is a synthetic form of this vitamin. Vitamin K is used... 

The alloxan and dialuric acid groups which arise from the oxidation and reduction processes and which constitute a redox system, were fixed to the gel. The reduction of an aqueous solution of alloxan to dialuric acid with the use of hydrogen gas was possible only in the presence of platinum. The alloxan present in the copolymer could not leave the gel and, therefore, the soluble redox system 2-methyl-naphthoquinone/ 2-methyI-naphthohydroquinone (vitamin K component) was added to the solution. The soluble redox system transferred the redox action to the fixed system in the interior of the gel. 

Several substances having vitamin K. activity have been isolated from natural sources. Vitamin Ki from alfalfa oil, is 2-methyl-3-phytyl-1,4-naphthoquinone. 

The term vitamin K2 was applied to 2-methyl-3-difarnesyl-l,4-naphthoquinone, m.p. 54 C, isolated from putrefied fish meal. It now includes a group of related natural compounds ( menaquinones ), differing in the number of isoprene units in the side chain and in their degree of unsaturation. These quinones also appear to be involved in the electron transport chain and oxidative phosphorylation. 

Donor substituents on the vinyl group further enhance reactivity towards electrophilic dienophiles. Equations 8.6 and 8.7 illustrate the use of such functionalized vinylpyrroles in indole synthesis[2,3]. In both of these examples, the use of acetyleneic dienophiles leads to fully aromatic products. Evidently this must occur as the result of oxidation by atmospheric oxygen. With vinylpyrrole 8.6A, adducts were also isolated from dienophiles such as methyl acrylate, dimethyl maleate, dimethyl fumarate, acrolein, acrylonitrile, maleic anhydride, W-methylmaleimide and naphthoquinone. These tetrahydroindole adducts could be aromatized with DDQ, although the overall yields were modest[3]. 

Quinones of various degrees of complexity have antibiotic, antimicrobial, and anticancer activities, eg, a2iddinornitosene [80954-63-8] (36), (-)-2-methyl-l,4-naphthoquinone 2,3-epoxide [61840-91 -3] (37), and doxombicin [23214-92-8] (adriamycin) (38) (see Antibiotics Chemotherapeutics, anticancer), ah of these natural and synthetic materials have stimulated extensive research in synthetic chemistry. 

Sequential applications of these methods yield naturally occurring anthraquinones, eg, macrosporin [22225-67-8] (86) in 83% yield from 2-chloro-6-methyl-7-hydroxy-l,4-naphthoquinone [76665-67-3] (87), which is produced in 78% yield from (26) (84). 

Thallium trinitrate oxidi2es naphthols and hydroquinone monoethers, respectively, to quinones and 4,4-diaIkoxycyclohexa-2,5-dienones, eg, 4,4-dimethoxy-2-methyl-2,5-cyclohexadienone [57197-11 -2] (108) (111,112). The yield of (108) is 89%. Because the monoacetal is easily converted to the quinone, the yield of 5-hydroxy-l,4-naphthoquinone [481-39-0] is 64%. 

In order to circumvent this problem, there has been significant activity directed toward the search for a less environmentally toxic and more selective oxidizing agent than chromium. For example, Hoechst has patented a process which uses organorhenium compounds. At a 75% conversion, a mixture of 86% of 2-methyl-l,4-naphthoquinone and 14% 6-methyl-l,4-naphthoquinone was obtained (60). Ceric sulfate (61) and electrochemistry (62,63) have also been used. 

Animals caimot synthesize the naphthoquinone ring of vitamin K, but necessary quantities are obtained by ingestion and from manufacture by intestinal flora. In plants and bacteria, the desired naphthoquinone ring is synthesized from 2-oxoglutaric acid (12) and shikimic acid (13) (71,72). Chorismic acid (14) reacts with a putative succinic semialdehyde TPP anion to form o-succinyl benzoic acid (73,74). In a second step, ortho-succmY benzoic acid is converted to the key intermediate, l,4-dihydroxy-2-naphthoic acid. Prenylation with phytyl pyrophosphate is followed by decarboxylation and methylation to complete the biosynthesis (75). 

Vitamin K3 (2-methyl-l,4-naphthoquinone, Menadione, Menaphthone) [58-27-5] M 172.2, m 105-106", 105-107". Recrystd from 95% EtOH, or MeOH after filtration. Bright yellow crystals which are decomposed by light. Solubility in EtOH is 1.7% and in C6H6 it is 10%. It IRRITATES the mucous membranes and skin. [Fieser J Biol Chem 133 391 1940.]... 

Methyl-l,4-naphthoquinone [ 1,4 -Naphthalenedione, 2-methyl-] Cyclopropanecarboxylie [Cyclopropan ecarboxylic acid] 2 -Cyclopropyl -3 -methyl [ 1,4-Naphthalenedione, 2-cyclopropyl-3-methyl-] 37 3... 

Acetoxy-1,4- naphthoquinone [ 1,4-Naphthalenedione, 2-(aoetyloxy)-] 4-Methyl-3-pentenoic [3-Pentenoic acid, 4-methyl-] 2-Acetoxy-3-(y,y-dimethylallyl) [1,4 -Naphthalen ed i one, 2-(acetyloxy)-3-(3-methyl-2-butenyl)-] 73 4... 

A = Acrylonitrile B = Benzoquinone C = Naphthoquinone D = 5,8-Quinolinequinone E = Methyl vinyl ketone F = Dimethyl acetylene dicarboxylate G = Methyl acrylate ... 

Acetoxy-3-(3-methyl-2-butenyl)-l,4-naphthoquinone, 56, 70 2-Acetoxy-1,4-naphthoquinone, 56, 70 Acrolein, 59, 2, 10, 203 Acrylonitrile, 59, 54... 

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. - ... 

The introduction of a substituent, especially a free or methylated hydroxyl group, determines a bathochromic shift of band II in the visible region. The 1,4-naphthoquinone absorption bands are at 245, 257, and 335 nm and the bands are at 243, 263, 332, and 405 nm for anthaqninone. The introduction of a substituent (especially a hydroxyl group) in the aromatic ring of a naphthoquinone determines a strong bathochromic effect (up to 100 nm) and some UV bands are shifted into the visible (vis) region. 

Sandur, S.K. et ah, Plumbagin (5-hydroxy-2-methyl-1,4-naphthoquinone) suppresses NF-kappa B activation and NF-kappa B-regulated gene products through modulation of p65 and I-kappa-B-alpha kinase activation, leading to potentiation of apoptosis induced by cytokine and chemotherapeutic agent, J. Biol. Chem., 281, 17023, 2006. 

The transformation of arenes in the troposphere has been discussed in detail (Arey 1998). Their destruction can be mediated by reaction with hydroxyl radicals, and from naphthalene a wide range of compounds is produced, including 1- and 2-naphthols, 2-formylcinnamaldehyde, phthalic anhydride, and with less certainty 1,4-naphthoquinone and 2,3-epoxynaphthoquinone. Both 1- and 2-nitronaphthalene were formed through the intervention of NO2 (Bunce et al. 1997). Attention has also been directed to the composition of secondary organic aerosols from the photooxidation of monocyclic aromatic hydrocarbons in the presence of NO (Eorstner et al. 1997) the main products from a range of alkylated aromatics were 2,5-furandione and the 3-methyl and 3-ethyl congeners. 

Thor, H., Smith, M.T., Hartzell, P., Bellomo, G., Jewell, S.A. and Orrenius, S. (1982). The metabolism of menadione (2-methyl-1,4-naphthoquinone) by isolated hepatocytes. A study of the impact of oxidative stress in the intact cell. J. Biol. Chem. 257, 12419-12425. 

The 13C NMR spectral data for 9, 16, and 17 are shown in Table 2. The chemical shifts of carbonyl carbons of anthraquinones are characteristically observed at about 180 ppm.9 The chemical shifts for carbonyl carbons of 1,4-naphthoquinone and 1,4-benzoquinone appear at about 185 ppm, while those of carbonyl carbons adjacent to a methylene or methyl carbon are at about 200 ppm. The chemical shifts of the Cl and C4 of 9 are observed at 200.8 ppm and assigned to the 1,4-diketo form 9a. In the 13C spectrum of 17, the chemical shifts of carbonyl carbons are at 199.9 and 172.2 ppm. The former value corresponds to a carbonyl carbon adjacent to the methylene carbon, and the latter corresponds to the carbonyl carbon in the 9-position. The methylene carbons of 17 show two signals at 34.5 and 23.8ppm. From these results, 17 is considered to exist exclusively as an unsymmetrical 4,9-diketo form, 17a. Thus, these NMR spectral data suggest... 

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