Synthesis and Photochromic Behavior of Novel Annelated 2H-Chromenes Derived from Hydroxy-9H-xanthen-9-ones

Coelho, Paulo J.; Carvalho, Luís M.; Silva, José C.; Oliveira‐Campos, Ana M. F.; Samat, A.; Guglielmetti, R.

doi:10.1002/1522-2675(20010131)84:1<117::aid-hlca117>3.0.co;2-f

Cited by 17 publications

(12 citation statements)

References 8 publications

(10 reference statements)

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“…The GSS reaction (Scheme 1) [11] offers a convenient method for preparing hydroxyxanthones and still enjoys a great popularity, due to usually accessible materials [for recent examples see [12][13][14][15][16][17][18][19][20][21][22][23][24][25]. It requires a salicylic acid derivative (1) and a suitable phenol (2) that are heated together with zinc chloride in phosphoryl chloride as solvent.…”

Section: Classical Methodsmentioning

confidence: 99%

“…Using Friedel-Crafts intramolecular cyclobenzylation in the preparation of xanthenes, by the action of dichloromethyl methyl ether and TiCl 4 on 4,4'-di-tert-butyldiphenyl ether has allowed an electrophilic substitution ortho to the diphenyl ether linkage and yielded 2,7-di-tert-butylxanthene in 38% along with 2,7-di-tert-butylxanthone in 38% [63]. In the diaryl ether condensation (Scheme 2 , c)) , microwave methodology has already assisted and replaced the common heating in the Ullmann reaction [17]. Microwave irradiation of a mixture of sodium 2-methoxyphenolate, sodium 2-chlorobenzoate, CuCl, and tris [2-(2-methoxyethoxy)-ethyl]amine gave 2-(2'-methoxyphenoxy)benzoic acid, which was then treated with polyphosphoric acid to provide 4-methoxyxanthone in 41% yield.…”

Section: Modifications To the Classical Methodsmentioning

confidence: 99%

“…Consequently, 1,2-dihydroxyxanthone (16) was first obtained as a major product by a multi-step synthesis through its intermediate 1-formyl-2-hydroxyxanthone (15) in very low yields (Scheme 5 a)) [70]. Snieckus and co-workers have accomplished the LDA-mediated synthesis of the natural products 2-hydroxy-1-methoxyxanthone (18) and 6-deoxyjacareubin (20) from the appropriate diaryl ether 2-carboxamides (17) and (19), respectively (Scheme 5 b)) [ direct metalation groups in contrast with the electrophilic substitution of the corresponding carboxylic acids and is probably driven by the Complex Induced Proximity Effect (CIPE) [71]. A CIPE has also been attributed to the success of an anionic Fries rearrangement (Scheme 2, f)), applied in the synthesis of dihydro-O-methylsterigmatocystin (see Table 2) [38].…”

Section: Modifications To the Classical Methodsmentioning

confidence: 99%

“…In order to investigate the photochromic properties of pyranoxanthones, their synthesis was achieved by condensation of 1,1-diphenylprop-2-yn-1-ol with the appropriate hydroxyxanthone under pyridinium ptoluenosulfonate (PPTS) catalysis [17]. However, 1-hydroxyxanthone (63), due to the hydrogen bonding between the hydroxyl group on C1 and the carbonyl at C9, failed to react with 1,1-diphenylprop-2-yn-1-ol in the presence of PPTS to give the pyranoxanthone (66).…”

Section: Pyranoxanthones and Furanoxanthonesmentioning

confidence: 99%

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Synthesis of Xanthones: An Overview

Sousa¹,

Pinto

2005

CMC

122

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Among the known synthetic routes to obtain xanthones, the Grover, Shah, and Shah reaction, the cyclodehydration of 2, 2'-dihydroxybenzophenones and electrophilic cycloacylation of 2-aryloxybenzoic acids are the most popular methods. Due to important biological applications of xanthones, some synthetic strategies leading to more complex derivatives have been widely explored in the past years. Thus, the purpose of this review is to report some recent improvements of the classical synthetic methods as well as of some non-classical methods to obtain simple oxygenated xanthones. The strategies for introduction of substituents into the xanthonic nucleus are also summarized. Furthermore, different approaches used to synthesize complex structures, with an emphasis on the total synthesis of bioactive natural products, accomplished in the last twenty years, are also discussed. Besides the synthesis of xanthones, the reactivity of the xanthonic nucleus and its role as a key intermediate for the synthesis of other important classes of compounds are also highlighted.

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Section: Classical Methodsmentioning

confidence: 99%

Section: Modifications To the Classical Methodsmentioning

confidence: 99%

Section: Modifications To the Classical Methodsmentioning

confidence: 99%

Section: Pyranoxanthones and Furanoxanthonesmentioning

confidence: 99%

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Synthesis of Xanthones: An Overview

Sousa¹,

Pinto

2005

CMC

122

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“…uraloides was subjected to column chromatography on silica gel, Sephadex LH-20, RP-18, as well as preparative HPLC to afford four new compounds, 1 -4 ( Fig. 1), and 16 known compounds: uralodin A (5) [20], furohyperforin (6) [21], quercetin [22], quercetin 3-O-a-l-rhamnofuranoside [23], quercetin 3-O-b-d-glucuronopyranoside [24], 3,4-epoxy-5-hydroxycyclohex-1-enecarboxylic acid [25], 1,5,6-trihydroxy-3-methoxyxanthone [26], 1,3,7-trihydroxyxanthone [27], 1,3,5trihydroxyxanthone [28], calycinoxanthone D [29], 1,3,5,8-tetrahydroxyxanthone [29], 1-hydroxyxanthone [30], 2,5-dihydroxyxanthone [31], kielcorin [32], 1,3,5,6-tetrahydroxy-4-prenylxanthone [33], and epicatechin-(7,8-bc)-4b-(hydroxyphenyl)-dihydroxy-2(3H)-pyranone [34].…”

mentioning

confidence: 99%

Polycyclic Polyprenylated Acylphloroglucinols and Chromone O‐Glucosides from Hypericum henryi subsp. uraloides

Chen

Cheng

et al. 2010

Chemistry & Biodiversity

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Two new C(30)-epimeric polycyclic polyprenylated acylphloroglucinols (PPAPs), named uralodins B and C (1 and 2, resp.), were isolated from the aerial parts of Hypericum henryi subsp. uraloides together with two new chromone glucosides, urachromones A and B (3 and 4, resp.), as well as 16 known compounds. Their structures were established by extensive NMR techniques and MS analysis. The epimers 1 and 2 always behaved like a single compound when examined by TLC, and were separated by HPLC. Their configuration was distinguished by comparative analysis of the NMR data with known analogues together with the ROESY experiment. All the isolated PPAPs were evaluated for their cytotoxic activities against HepG2, SGC7901, HL-60, and K562 cell lines. Compound 1 showed modest cytotoxic activities against SGC7901 and HL-60 cell lines, and 2 showed modest cytotoxic activities against HepG2, SGC7901, HL-60, and K562 cell lines.

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Synthesis of Photochromic Dyes Based on Annulated Coumarin Systems

Cerqueira

Oliveira‐Campos

Coelho

et al. 2002

HCA

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Novel 2H-chromenes derived from hydroxycoumarins were synthesized, and their photochromic behaviour was studied under flash-photolysis conditions, showing a wide absorption range in the visible region. All the compounds exhibit low fluorescence, which apparently has no negative effect on their photochromic properties.1. Introduction. ± Photochromic systems have the ability to undergo a reversible transformation between two states giving rise to different absorption spectra, induced, at least in one direction, by electromagnetic radiation [1]. If one of the states absorbs in the visible region under appropriate conditions, a noticeable, reversible change of color occurs as a consequence of the transformation. Such phototransformations open a wide field of potential applications based upon the reversible color change or upon reversible changes in physical or chemical properties as a consequence of the structural modification accompanying such transformations [2].In the last two decades, the commercial success of plastic ophthalmic lenses that darken in sunlight, increased the interest in the search for new matrix-compatible organic molecules that allow the development of photochromic systems with enhanced properties. In the field of these variable-transmission optical materials, the main characteristics strived for, are i) the ability to be activated by sunlight (heliochromism) and bleached through a thermal process, ii) extended absorption in the visible region to provide a neutral colour upon irradiation, iii) a suitable fading rate (which is related to the stability of the coloured state), iv) high efficiency of coloration upon irradiation (−colorability×), and v) a high resistance to photodegradation (−fatigue resistance×) [3].Together with spiro-pyrans and spiro-oxazines, the 2H-chromenes (2H-[1]benzopyrans) have been extensively studied. These colorless molecules undergo, upon near-UV irradiation, a photo-induced reversible cleavage of the C(2)ÀO bond, followed by isomerization, leading to a (quasi-planar) colored open form that returns to the starting material by heating or by irradiation with visible light (Scheme 1).In the activated state, these molecules display a yellow-orange color (400 ± 500 nm) making them very attractive to be incorporated into lenses together with spirooxazines. The latter are excellent photochromic compounds, but they exhibit relatively narrow absorption bands, usually in the 560 ± 630 nm range, making it difficult to obtain

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Synthesis and Photochromic Behavior of Novel Annelated 2H-Chromenes Derived from Hydroxy-9H-xanthen-9-ones

Cited by 17 publications

References 8 publications

Synthesis of Xanthones: An Overview

Synthesis of Xanthones: An Overview

Polycyclic Polyprenylated Acylphloroglucinols and Chromone O‐Glucosides from Hypericum henryi subsp. uraloides

Synthesis of Photochromic Dyes Based on Annulated Coumarin Systems

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