Chlorination of 1,4-dihydroxythioxanthen-9-one

Loskutov, V. A.; Gatilov, Yu. V.; Mamatyuk, V. I.

doi:10.1134/s1070428008040295

Cited by 5 publications

(7 citation statements)

References 8 publications

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“…IR spectrum, ν, cm -1 : 1764 (C=O ester), 1628 (C=O thioxanthene). 1 Reaction of quinizarin with SOCl 2 . 0.56 g of quinizarin was added to 70 ml of SOCl 2 cooled to 0°C, the mixture was stirred at room temperature for 4 h and left standing without stirring for 20 h, then it was poured on ice, and the red precipitate was separated.…”

Section: 3-dichlorothioxanthene-149-trione (Ii)mentioning

confidence: 99%

“…The reaction in DMSO gave a complex mixture of products where by TLC and 1 H NMR we found 2-and 3-monochlorothioxanthenones III and V, and also small quantities of 2,3-dichlorothioxanthenone VI [1] and thioxanthenone I. According to the 1 H NMR data the ratio of isomers III and V in the mixture was ~1 : 4, evidently due to the activation of the position 3 in compound IV toward the nucleophilic addition of a chloride ion thanks to the protonation of the carbonyl group C 1 =O and the formation therewith a hydrogen bond with the oxygen atom of the group C 9 =O (cf.…”

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confidence: 98%

“…We established that thioxanthenone I at heating with SOCl 2 same as in the reaction with chlorine [1], underwent oxidative chlorination giving 2,3-dichlorothioxanthenetrione (II). We succeeded in avoiding the oxidative effect of the thionyl chloride by lowering the reaction temperature to ambient.…”

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confidence: 99%

“…We formerly described [1] a chlorination of 1,4-dihydroxythioxanthen-9-one (I) whose derivatives merit attention as biologically active compounds [2] and photoinitiators of the polymerization of unsaturated compounds [3]. It was established that in the reaction with molecular chlorine at 20-25°C the products of oxidative chlorination were obtained, dichlorothioxanthenand tetrachlorotetrahydrothioxanthene -1,4,9-triones. In this investigation we studied the possibility of introduction of the chlorine atoms into thioxanthenone I avoiding the oxidation of the hydroquinone system of the molecule into a quinoid structure.…”

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Syntesis of 2- and 3-chloro-1,4-dihydroxythioxanthen-9-ones

2010

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Section: 3-dichlorothioxanthene-149-trione (Ii)mentioning

confidence: 99%

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Syntesis of 2- and 3-chloro-1,4-dihydroxythioxanthen-9-ones

2010

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“…Acid II was converted into 1,4-dihydroxythioxanthen-9-one (I) by the action of concentrated sulfuric acid [6]. We found in [9] that analogous cyclization occurs in polyphosphoric acid, and the structure of thioxanthenone I thus obtained was confirmed by comparison of its spectral parameters with those reported in [10]. However, our attempts to effect cyclization of 1,4-naphthoquinone and 1,4-anthraquinone derivatives V, VIII, and XI in concentrated sulfuric acid were unsuccessful.…”

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Reaction of thiosalicylic acid with 1,4-quinones and cyclization of the resulting arylsulfanylbenzoic acids

Loskutov

Beregovaya

2009

Russ J Org Chem

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Thiosalicylic acid reacts with 1,4-benzoquinone to give 2-(1,4-dihydroxyphenylsulfanyl)benzoic acid which undergoes intramolecular cyclization to 1,4-dihydroxythioxanthen-9-one in the presence of dehydrating agents. Cyclization of arylsulfanylbenzoic acids obtained by reaction of thiosalicylic acid with 1,4-naphtho-and anthraquinones leads to 1,4-quinone derivatives, benzo-and naphthothioxanthenetriones.Dihydroxythioxanthene derivatives were found to exhibit biological activity [1-4] and initiate photochemical polymerization [5]. The most widely known representative of this series of compounds is 1,4-dihydroxythioxanthen-9-one (I) which was synthesized about 100 years ago [6] by cyclization of 2-[(2,5-dihydroxyphenyl)sulfanyl]benzoic acid (II); the latter was prepared from benzoquinone III and thiosalicylic acid (IV) in acetic acid (Scheme 1).1,4-naphthoquinone (VII) in ethanol gave 2-(1,4-dioxo-1,4-dihydronaphthalen-2-ylsulfanyl)benzoic acid (V) and benzothioxanthene VI (Scheme 2). However, the parameters of the products given in [4] are not fully consistent with the assumed structures. In particular, the 1 H NMR spectrum of acid V lacks a signal typical of quinoid compounds which should be located in a stronger field than signals from aromatic protons [7]. Therefore, the assignment of structures of compounds I and II made in [4] seems to be insufficiently substantiated. The goal of the present work was to elucidate the structure of compounds formed by reaction of thiosalicylic acid (IV) with 1,4-benzo-, 1,4-naphtho-, and 1,4-anthraquinones and of their cyclization products, thioxanthen-9-one derivatives.We have found that acid IV reacts with 1,4-benzoquinone (III) at room temperature not only in acetic acid [6] but also in other solvents (such as diethyl ether and ethanol) and that the reaction occurs as 1,4-addition of the nucleophile at the conjugated bond system of quinone III with participation of one carbonyl group (which is typical of quinones), followed by rearrangement of the adduct to produce dihydroxy-substituted diphenyl sulfide II. The 1 H NMR spectrum of the isolated product contained signals from aromatic protons and three signals assignable to hydroxy protons. A broadened downfield signal at δ 12-14 ppm was assigned to proton in the carboxy group, and the position of the two other OH signals (2′-OH and 5′-OH; δ 8.93 and 9.03 ppm) indicated equal contributions of the corresponding protons to exchange processes. In the IR

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Recent Advances in Organic Reactions Involving Elemental Sulfur

2017

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Elemental sulfur hasb een known since Antiquity and found widespread applications in the preparation of black gunpowder,t he synthesis of sulfuric acid as well as other sulfur-containing compounds,a nd the vulcanization of rubber.O ver the last several years,wehave come to better understand its properties andd iscover more applications of elementals ulfuri ns ynthetic organic chemistry.T his review summarizes the advancesf rom 2000i nt he construction of organic molecules using elemental sulfur via sulfuration, oxidation, reduction and redox condensation processes.

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Chlorination of 1,4-dihydroxythioxanthen-9-one

Cited by 5 publications

References 8 publications

Syntesis of 2- and 3-chloro-1,4-dihydroxythioxanthen-9-ones

Syntesis of 2- and 3-chloro-1,4-dihydroxythioxanthen-9-ones

Reaction of thiosalicylic acid with 1,4-quinones and cyclization of the resulting arylsulfanylbenzoic acids

Recent Advances in Organic Reactions Involving Elemental Sulfur

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