A Novel and Efficient Method for the Synthesis of New Hydroxythioxanthone Derivatives

Sharghi, Hashem; Beni, Ali Reza Salimi

doi:10.1055/s-2004-831253

Cited by 28 publications

(6 citation statements)

References 11 publications

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“…mp 288-289°C (from DMSO-EtOH). The IR and 1 H NMR spectra of compound I were consistent with those reported in [10].…”

Section: Methodssupporting

confidence: 77%

“…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.…”

supporting

confidence: 70%

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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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“…mp 288-289°C (from DMSO-EtOH). The IR and 1 H NMR spectra of compound I were consistent with those reported in [10].…”

Section: Methodssupporting

confidence: 77%

supporting

confidence: 70%

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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“…Bis(2,4,6-trichlorophenyl) oxalate (TCPO) was synthesized from the reaction of 2,4,6-trichlorophenol and oxalyl chloride in the presence of tri-ethylamine as described elsewhere [16]. Luminophore DMT was synthesized and purified as reported before [17] and b-CD was purchased from Fluka and used directly.…”

Section: Chemical Reagents and Apparatusesmentioning

confidence: 99%

Peroxyoxalate chemiluminescence of 1,4-dihydroxy-3-methyl-thioxanthone and quenching effect of β-cyclodextrin

Yari

Karami

2011

J Incl Phenom Macrocycl Chem

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The chemiluminescence generated from the reaction of bis(2,4,6-trichlorophenyl) oxalate (TCPO), hydrogen peroxide and 1,4-dihydroxy-3-methyl-thioxanthone (DMT) was investigated. Effects of reacting components, solvent and concentrations of TCPO, sodium salicylate, hydrogen peroxide and DMT were studied and their optimal values were determined. In addition, the influences of b-Cyclodextrin (b-CD) on the peroxyoxalate chemiluminescence (PO-CL) system of DMT were examined at optimized condition. The results showed that the presence of b-CD causes both enhancing and quenching effects on PO-CL system of DMT based upon its concentration. The Stern-Volmer quenching constant (K q ) was evaluated as 2.32 9 10 4 M -1 (R 2 = 0.991) by creating a linear regression plot on experimentally obtained data. This study resulted in satisfactorily determination of b-CD in the range 5.0 9 10 -6 to 1.0 9 10 -4 M.

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“…Synthetic organic routes followed by using heterogeneous catalysts have advantages over their counterparts in which, used-catalyst can be easily recycled [21]. As a part of our continued efforts to utilize heterogeneous catalysts for developing organic reactions [37][38][39][40][41][42][43][44][45][46][47][48][49][50], herein we report on a new and reused catalyst system based on copper on charcoal (Cu/C). This heterogeneous catalyst system exhibits an excellent catalytic performance for the construction of the 2-arylbenzimidazoles framework.…”

Section: Introductionmentioning

confidence: 99%

Simple, Efficient, and Applicable Route for Synthesis of 2-Aryl(Heteroaryl)-Benzimidazoles at Room Temperature Using Copper Nanoparticles on Activated Carbon as a Reusable Heterogeneous Catalyst

et al. 2011

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A Novel and Efficient Method for the Synthesis of New Hydroxythioxanthone Derivatives

Abstract: We describe the synthesis of some new hydroxythioxanthones by treatment of thiosalicylic acid (TSA) with various substituted phenols in the presence of Al 2 O 3-CH 3 SO 3 H (AMA). Most of the reactions show high regioselectivity and produce thioxanthones in good yields.

Cited by 28 publications

References 11 publications

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

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

Peroxyoxalate chemiluminescence of 1,4-dihydroxy-3-methyl-thioxanthone and quenching effect of β-cyclodextrin

Simple, Efficient, and Applicable Route for Synthesis of 2-Aryl(Heteroaryl)-Benzimidazoles at Room Temperature Using Copper Nanoparticles on Activated Carbon as a Reusable Heterogeneous Catalyst

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