4- Chloro-l,2-naphthoquinone

Photolytic. The UV absorption band for dichlone is 330 nm (Gore et al., 1971). Irradiation of dichlone in a variety of organic solvents (benzene, isopropanol, ethanol) using UV light produced dehalogenated compounds. In the absence or presence of oxygen, 2-chloro-l,4-naphthoquinone,... 

This enzyme [EC 1.14.99.27] catalyzes the reaction of 5-hydroxy-l,4-naphthoquinone with AH2 and dioxygen to produce 3,5-dihydroxy-l,4-naphthoquinone, A, and water. The enzyme can also use 1,4-naph-thoquinone, naphthazarin, and 2-chloro-l,4-naphthoquinone as substrates, but not other related compounds. 

Many furanquinones, derivatives of 84, were formed in the reaction of 2,3-dichloro-1,4-naphthoquinone with reactive methylene compounds in the presence of various basic reagents. The reaction can proceed in one step or by a two-step route via 3-substituted 2-chloro-l,4-naphthoquinones (1900CB2402 53P1A(A)534 57JA5489 65JOC3819 71ZOR1031). 

Among 64 derivatives of 2-chloro-l. 4-naphthoquinone two (III and IV) showed high activity ... 

Chemical/Physical. An aqueous solution containing chlorine dioxide in the dark for 3.5 d at room temperature oxidized 2-methylnaphthalene into the following l-chloro-2-methylnaphtha-lene, 3-chloro-2-methylnaphthalene, l,3-dichloro-2-methylnaphthalene, 3-hydroxymethylnaphtha-lene, 2-naphthaldehyde, 2-naphthoic acid, and 2-methyl-l,4-naphthoquinone (Taymaz et al., 1979). 

Exposure of 2-AI-ethylaniIino-3-chloro-l,4-naphthoquinone (CCLIX) in ethanol to sunlight yields 2-anilino-3-chloro-l,4-naphthoquinone (CCLX). The mechanism of the reaction is not clear.296... 

Quinoline derivatives (60) have been synthesized by the reaction of 5-alkyl-l,3,4-thia-diazol/oxadiazol-2-thiols with 7-chloro-6-uoro-2,4-dimethylquinoline and by the reaction of 2-hydroxy-l,4-naphthoquinone with 2-chloro-3-formyl-4-methyl/ 6-methyl/7-methyl/8-methylquinolines, respectively, on basic alumina using micro-waves (Kidwai et al., 2000). 

Amino-3-chloro-l, 4-naphthoquinone, 300 9-(2-Amino-2-deoxy-/3-D-glucopyranosyl)... 

The aziridine 9, prepared from 2,3-dichloro-l,4-naphthoquinone by displacement of the first chlorine with alanine, acetylation, and replacement of the remaining chlorine with aziridine, is converted into the benzoquinoxaline dione 10 on treatment with acid. ° 2-Amino-3-chloro-l,4-naphthoquinone is converted by successive treatment with chloroacetyl chloride and diethylamine into the benzoquinoxaline trione 12. The intermediate 11 is not isolated, but with other... 

A series of 2-substituted 3-chloro-1,4-naphthoquinones were synthesized and their anti-inflammatory activities were evaluated. The structure-activity relationships in this series were also examined. Most of the 2-alkyl/arylcarboxamido derivatives of 3-chloro-l,4-naphthoquinones showed potent activity [122,123], Selected naphthoquinone compounds were investigated for 5-lipoxygenase inhibiting and antioxidative properties. There is a clear-cut correlation of both qualities in those compounds with a 3-hydroxy function and with two, one or without any tert-butyl group at the phenyl moiety [124],... 

McLachlan calculation of spin densities as a function of twist angle.-EPR spectra simulated with a-values from ENDOR in fairly good agreement with experiment. ) Or 2-chloro- or 2-br9mo-l,4-naphthoquinone. ... 

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). 

Bromo-3-hydroxy-l,4-naphthoquinone (bromolawsone) and 2,3-di-chloro-1,4-naphthoquinone react similarly [93CCC1191,93IJC(B)365]. Further examples have been reported (85MI1). 

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. 

A solution of sodium nitrate (0.69 g, 10 mmol) in water (5 ml) was added at 0-5°C to a solution of 6-amino-2,3-dimethoxy-l,4-naphthoquinone (1.17 g, 5 mmol) in 5 1 acetic acid water (25 ml) containing concentrated hydrochloric acid (1.7 ml). A further quantity of sodium nitrite (0.69 g) was then added to the reaction mixture after cooling to -5°C, followed by a solution of cuprous chloride (0.6 g) in concentrated hydrochloric acid (5 ml). The mixture was allowed to warm to room temperature and solid cuprous chloride was added portionwise until the mixture assumed a green color. Water was then added to the reaction mixture and the precipitated yellow solid filtered off, washed with water and recrystallized from methanol water (2 1) giving 1.01 g of 6-chloro-2,3-dimethoxy-l,4-naphthoquinone, melting point 93-94°C (from ether-petrolium ether). 

A photoinduced substitution reaction initiated by electron transfer has also been proposed to account for the formation of 2-chloro-3-(2-thienyl)-1,4-naphthoquinones (217) from 2,3-dichloro-l, 4-naphthoquinone (215) and thiophenes (216)623 (equation 160). 

Chloro-3-(o -cyano-Q -carbethoxy)methyl-l,4-naphthoquinone 603 is cyclized by using Na2S to yield the corresponding thiophene 604 <1999JHC15>. Treatment of the 3-bromopropene 605 with NaSH affords tetrasubstituted thiophene 606 <2005SC2251>. 

The bisquinone 70 was obtained by condensation of 2-anilino-3-chloro-1,4-naphthoquinone with sodium sulfide and 2,3-dichloro-l,4-naphthoqui-none. The product, a pentacyclic thiazine, lost sulfur upon heating to give 70. This diquinone can be reduced with SnCl2 and subsequent oxidation with air yielded the monoquinone 71 (23CB1291). 

From 3-chloro-l,4- or -1,2-naphthoquinones and sodium sulfide, the ben-zolog of 395, and with o-aminothiophenol the isomeric quinone 396, were prepared (71ZOR1031 86JCS(P1)2233). Compound 396 rapidly isomerizes... 

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