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Review on 4-Hydroxycoumarin Chemistry: Synthesis, Acylation and Photochemical Properties

Jules Yoda*, Abdoulaye Djandé, Lamine Cissé, Akoun Abou, Léopold Kaboré, Adama Saba

Laboratory of Molecular Chemistry and Materials, Research Team: Organic Chemistry and Phytochemistry, University Joseph KI-ZERBO, 03 BP 7021 Ouagadougou 03, Burkina Faso

Abstract: Hydroxycoumarins are important compounds exhibiting several physical, chemical and biological properties. These compounds represent a part of secondary metabolites that are natural compounds and are studied for their importance in organic synthesis. Among the most well-known hydroxycoumarins are 7-hydroxycoumarin and 4-hydroxycoumarin. The objective of this review is to raise awareness of the reactivity of 4-hydroxycoumarin and its applications. In this study, we review the methods of synthesis and acylation of this compound as well as studies on the photochemical properties of its derivatives. Several methods for the synthesis of 4-hydroxycoumarin have been described in the literature, most of which use simple phenol and 1-(2-hydroxyphenyl)ethanone or 2’-hydroxyacetophenone as starting compounds. Other synthesis pathways exist, but they are based on intermediate synthesis compounds. About 4-hydroxycoumarin acylation, the literature reports two main types of acylation such as C-acylation and O-acylation. Several authors have synthesized and studied C-acylation in liquid medium and the solvent free. As for O-acylation, its compounds are more recent and less studied. Some studies have also been conducted on the photochemical properties of 4-hydroxycoumarin and its derivatives. Some compounds have proven to be excellent UV absorbers, others have fluorescent properties. With regard to the photo-acid properties generally sought in the hydroxycoumarins group, studies have shown that 4-hydroxycoumarin, unlike 7-hydroxycoumarin, cannot be considered as an active photo-acid.

Keywords: coumarin, 4-hydroxycoumarin, acylation, photochemical properties, fluorescence

Received September 15, 2019; Revised November 04, 2019; Accepted November 18, 2019

Citation: Jules Yoda, Abdoulaye Djandé, Lamine Cissé, Akoun Abou, Léopold Kaboré, Adama Saba, Review on 4-Hydroxycoumarin Chemistry: Synthesis, Acylation and Photochemical Properties. World Journal of Organic Chemistry, 7 (1). 19-30. January 2019. doi:10.12691/wjoc-7-1-4

1. Introduction

Coumarins are one of the most significant families of natural product compounds and are also important in synthetic organic chemistry. They have been widely used as starting materials or precursor molecules in the pharmaceutical sciences [1,2,3,4,5,6]. They are used in perfumery [7,8,9], cosmetic [10] and agrochemical industries [11,12]. Coumarin derivatives are also used as fluorescent coumpounds due to their inherent photochemical characteristics. Many coumarin derivatives have been commercialized as blue-green lasers for fluorescent labels and fluorescent probes [13,14,15,16,17,18,19]. They exhibit intense fluorescence upon substitution with various functional groups at different positions [20].

This study focuses on hydroxycoumarins, specifically 4-hydroxycoumarin 1, this compound (Figure 1) which known as 4-hydroxy-2H-chromen-2-one and 4-hydroxy-1-benzopyran-2-one or 2-Hydroxychromen-4-one in IUPAC system. It has other lesser-known names such as 4-coumarinol and benzotetronic acid. Its structure contains three tautomeric keto-enol forms [21,22] (Figure 2).

Figure 1. Numbered structure of 4-hydroxycoumarin

Figure 2. Tautomeric forms of 4-hydroxycoumarin

4-hydroxycoumarin represent nowadays, an important precursor in the realm of organic synthesis; its derivatives have shown a remarkably broad spectrum of biological activities [23,24,25,26,27,28,29,30]. They can be among others, anticoagulant [23,24], antibacterial [25,26], anti-inflammatory [27] and anti-tumoral [28] anti-pyretic [29] and anti-viral [30] properties. The acyl derivatives in particular have different biological activities for variable acyl groups. It has been reported by Crovatto et al. [31] that the activity evolves with the length of the carbon chain of the acyl group. With a short-chain acyl group, the compound has high ovicide rates, but the longer the chain, the lower the activity. The 3-acyl-4-hydroxycoumarins possessing long-chain (carbon number 10) with a terminal ethylene bond, have a high antibacterial activity. This review is not exhaustive, the objective of the study is to enhance the title compound, its reactivity, its acyl derivatives and its applications. Thus, in this review, we report the synthesis and acylation of 4-hydroxycoumarin. The photochemical properties of this compound and its derivatives will then be investigated. Herein, the discussion is supported by numerous lucid diagrams and reaction schemes, figures are supported by relevant and up-to-date references from the original literature.

2. Synthetic routes

2.1. Chemical reactions

Shah et al. [32] were among the first to be interested in the synthesis of 4-hydroxycoumarin and its derivatives. In their investigation, they noted the existence of three main methods for the synthesis of 4-hydroxycoumarins. Among these, a synthetic pathway first leads to the 3-substituted 4-hydroxycoumarin and this intermediate can then be converted to 4-hydroxycoumarin 1. This is the condensation reaction of acetyl salicyloyl chlorides with acetoacetic, cyanoacetic or malonic ester. They subsequently discovered a new simple process in which phenol is treated with an equimolar proportion of malonic acid in the presence of a mixture of a double to triple molar amount of each anhydrous zinc chloride and phosphorus oxychloride as a condensation agent. In recent advances, there are many synthetic approaches to 4-hydroxycoumarin 1 [33], but the synthetic pathways using 2’-hydroxyacetophenone or phenol as starting marterials are still the most conventional (Figure 3).

Figure 3. 4-hydroxycoumarin synthesis routes

2.2. Use of Phenol and 2’-hydroxyacetophenone as Starting Marterial

2.2.1. Phenol as Starting Material

The Pechman reaction is one of the methods widely applied in a practical sense, to synthesize coumarins, because it involves the condensation of phenols with β-ketoesters or carboxylic acids. To obtain 4-hydroxycoumarin 1 with a quantitative yield of 64%, Phenol 2 is treated with an equimolar proportion of a malonic acid 3 in phosphorus oxychloride (POCl₃) containing two equimolars of the amount of anhydrous zinc chloride (ZnCl₂) [34] (Figure 4).

The mixture of phenol 2 with Meldrum’s acid or isopropylidene malonate 4 under solvent-free condition leads to an intermediate compound 3-oxo-3-phenoxypropanoic acid 5. This compound is then converted into 4-hydroxycoumarin 1 by two routes with different yields. 3-oxo-3-phenoxypropanoic 5 is treated with the Eaton reagent (7.7 wt % phosphorus pentoxide solution in methane sulfonic acid) or polyphosphoric acid (PPA) to give 4-hydroxycoumarin 1 (Figure 5) [35,36,37].

2.2.2. 2’-hydroxyacetophenone as Starting Material

1-(2-hydroxyphenyl)ethanone or 2’-hydroxyacetophenone 6 reacts with an equimolar amount of acylating agents 7 such as phosgene 7a, dimethyl carbonate 7b or diethyl carbonate 7c. The reaction is carried out in the presence of a suitable base in toluene or anhydrous xylene to give 4-hydroxycoumarin 1 with variable yield (Figure 6). When analysing the different yields, it is found that sodium hydride is the most effective base (Table 1) [38,39,40,41].

Figure 4. Compound 1: Synthesis by Pechman reaction

Figure 5. Compound 1: Synthesis using Meldrum’s acid

Figure 6. Compound 1: synthesis using 2’-hydroxyacetophenone

Table 1. Experimental conditions for obtaining compound 1

Figure 7. Compound 1: formation by condensation of 1-(2-hydroxyphenyl)ethanone

The condensation of 2’-hydroxyacetophenone 6 with trichloroacetonitrile in the presence of N-methylanilinomagnesium bromide gives (Z)-3-amino-3,4,4-trichloro-1-(2-hydroxyphenyl)but-2-en-1-one 9, which is transformed into 2-(trichloromethyl)chromones 10 during treatment with concentrated hydrochloric acid. Hydrolysis catalyzed by potassium hydroxide results in 4-hydroxycoumarin 1[42] (Figure 7).

2.3. Use of Acyl Derivatives of 4-hydroxycoumarin

Liao et al. [43] reported a novel synthesis pathway to switch from O-acylation 11 compound to C-acylation 12 compound of 4-hydroxycoumarin 1. The reaction first leads to a 4-coumarinyl carboxylate 11 corresponding to the O-acylation derivative. In the presence of potassium cyanide, this compound gives 3-acyl-4-hydroxycoumarin by the displacing of the acyl group (RCO). Using this method, 4-hydroxycoumarin can be obtained after acid hydrolysis (Figure 8).

2.4. Use of Cleavage Reaction

Ganguly et al. [44] described a method of synthesizing 4-hydroxycoumarin 1 from 4-allyl-coumarinyl ether. The cleavage reaction uses a catalytic amount of palladium on activated carbon in methanol, in combination with ammonium formate This reaction can also be catalyzed by other reagents such as molecular iodine [45] (Figure 9).

2.5. Use of Deacylation and Decarboxylation Reactions

Jung et al. [46] published a simple and facile method for obtaining 4-hydroxycoumarin. This synthesis pathway uses 3-acetyl-4-hydroxycoumarin 14 as the starting compound. By a deacylation reaction catalyzed by HCl acid, 4-hydroxycoumarin 1 is isolated in a 90% yield (Figure 10). Similarly, 3-carbethoxy-4-hydroxycoumarin 15 leads to 4-hydroxycoumarin-1 through acid-catalyzed hydrolysis and decarboxylation [46] (Figure 11).

Figure 8. Compound 1 : formation using 4-acyl-3-hydroxycoumarin and 4-coumarinyl carboxylate

Figure 9. Compound 1: formation by cleavage reaction

Figure 10. Compound 1: formation by deacylation reaction

Figure 11. Compound 1 formation by decarboxylation reaction

2.6. Photooxygenation of Chromone-2-carboxylic Acid

Another approach was reported by Kawata et al. [47] via the photooxygenation of chromone-2-carboxylic acid 16 in ethanol solution. The reaction seems to proceed via the decarboxylation followed by the addition of the oxygen molecule (Figure 12).

Figure 12. Compound 1: formation by photooxygenation of chromone-2-carboxylic Acid

3. Acylation of 4-hydroxycoumarin

3.1. Acylation Reaction

Hydroxycoumarins react remarkably quickly with several acyl chlorides to give coumarin acyl derivatives [48,49,50,51,52,53,54,55,56,57,58,59,60,61]. Previous works has shown that phenols, particularly hydroxycoumarins and some similar compounds such as homophthalic anhydrides (isochroman-1,3-dione), are suitable for acylation reactions with different results. Indeed, in the case of homophthalic anhydride, in the case of homophthalic anhydride, there is only C-acylation, where as in the case of hydroxycoumarin derivatives, acylation could be either O-acylation or C-acylation [48,51]. In the literature, several processes for the acylation of 4-hydroxycoumarin have been described. According to the mechanism of this acylation in a basic medium, an alcoholate anion 1i is formed at the hydroxyl function. This anion could be in equilibrium with mesomeric carbanion 1ii as follows (Figure 13). In general, triethylamine (Et₃N), pyridine (Py), piperidine and potassium cyanide (KCN) are used as appropriate bases.

3.2. C-acylation of 4-hydroxycoumarin

3.2.1. Synthesis of 3-acyl-4-hydroxycoumarin

Cravotto et al. [51] studied the acylation of 4-hydroxycoumarin 1 using various long-chain acid chlorides 16 as acylating agents and piperidine as an appropriate base. The action of acid chlorides (RCOCl) with an aliphatic R group on 4-hydroxycoumarin 1 is carried out under the effect of 21 KHz ultrasound. The authors obtained a quantitative C-acylation in the presence of catalytic amount of piperidine (Figure 14). Similarly, 3-(10'-undecenoyl) chroman-2,4-dione 17a (n = 8) was prepared by acetylation of 4-hydroxycoumarin 1 with 10-undecenoyl chloride 16a in pyridine also containing a catalytic amount of piperidine [52,53].

The method proposed by Liao et al., for the acylation of 4-hydroxycoumarin 1 [43] is rather classical. The substrate reacts with acid chloride 18 in the presence of both triethylamine in methylene chloride to give the corresponding enol ester (o-acyl derivatives) which were further treated with potassium cyanide without purification at ambient temperature for two days to obtain a good yield of the 3-acyl-4-hydroxycoumarin (Figure 15).

Figure 13. Mesomeric equilibrium between alcoholate anion and carbanion from 4-hydroxycoumarin

Figure 14. 3-acyl-4-hydroxycoumarin synthesis under ultrasound

Figure 15. Formation of 3-acyl-4-hydroxycoumarin with R= Alkyl or aryl

Figure 16. Formation of 3-formyl-4-hydroxycoumarin

Rad-Moghadam and Mohseni [60], in the absence of solvent, were able to obtained 3-formyl 4-hydroxy coumarin 20. The reaction is performed under the effect of microwaves between 4-hydroxycoumarin and ethyl orthoformate H-C(OEt)3 in the presence of a catalytic amount of p-toluenesulfonic acid (APTS). The final compound is obtained with a quantitative yield (Figure 16).

3.2.2. Synthesis of 3-acetyl-4-hydroxycoumarin

Many synthetic approaches to 3-acetyl-4-hydroxycoumarin 22 have been reported using 4-hydroxycoumarin as starting material. Abdoullah S. AL-AYED et al. [50] prepared 3-acetyl-4-hydroxycoumarin 22 using the method described by Dholakia et al. [57]. This method involves reacting 4-hydroxycoumarin 1 with glacial acetic acid 21, in the presence of phosphorus oxychloride (POCl3) as the catalyst (Figure 17).

The direct acetylation of 4-hydroxycoumarin 1 in the presence of triethylamine in methylene chloride 23 gave the corresponding enol esters (acetate of 4-coumarinyl) 24, which were further treated with trichlorophosphate in acetic acid or potassium cyanide with triethylamine in dichloromethane. Using pyridine or piperidine as a catalyst to obtain 3-acetyl-4-hydroxycoumarin 22 [54,55,56] (Figure 18).

Figure 17. Formation of 3-acetyl-4-hydroxycoumarin

Figure 18. Formation of 3-acetyl-4-hydroxycoumarin via acetate of 4-coumarinyl

Figure 19. Formation of 3-acetyl-4-hydroxycoumarin using phosphorous oxychloride

Synthetic routes for 3-acetyl-4-hydroxycoumarin 22 have been published via the reaction using 1 with acetic acid or acetic anhydride 25 in the presence of phosphorous oxychloride as a catalyst [56] (Figure 19).

We note that the most recent studies mention C-acylation. To obtain O-acylation therefore seems rather difficult. However, the work of Tapase et al. and Saba et al. have recently led to the development of new O-acylation derivatives of 4-hydroxycoumarin, as indicated below.

3.3. O-acylation of 4-hydroxycoumarin

3.3.1. Solvent-free Synthesis under Microwave

The principle of preparation of coumarinyl carboxylates is an O-acylation of 4-hydroxycoumarin by the action of acyl chlorides or equivalent acid anhydrides in a basic medium [61]. Tapase et al. [48] prepared a series of O-acylated coumarins by the action of acid halides with 4-hydroxycoumarin, either in basic medium (NaOH) or in the presence of copper salts. The reactions were carried out in a microwave oven in the absence of solvent. The authors used 2.5 mmol of 4-hydroxycoumarin in an aqueous solution of sodium hydroxide. The mixture is then irradiated in 600 W for 60 seconds to obtain a solid coumarin salt. An organic halide (3.0 mmol) is then mixed with the resulting solid and a few drops of water have been added. The reaction mixture was irradiated at the specified power for the specified time. After cooling to room temperature, the final product was washed with water to remove unreacted salt and excess sodium hydroxide. Finally, it was purified by recrystallization (Figure 20).

Figure 20. Microwave synthesis of O-acylated 4-hydroxycoumarin derivatives

It was observed that the presence of a few drops of water was very important for the NaOH method. The main effect was that the water could effectively couple to the microwaves or make the reaction mixture homogeneous. According to the authors, the absence of water would affect the efficiency of the reaction.

3.3.2. Synthesis Using HSAB Theory

Saba et al, [62,63] have developed an acylation method based on the "Hard and Soft Acid Base" (HSAB) theory developed by R. G. Pearson [64], in the choice of experimental conditions. It is indeed necessary to choose the base to be used taking into account the nature of the acylating agent. The research of Pearson has shown that hard bases react quickly and easily with hard acids while soft bases react well with soft acids. The choice of solvent is also an important factor that directly influences performance. This approach allowed isochromandione and hydroxycoumarins to be acylated [65,66,67,68,69]. Through this method, new O-acyl 27a-e derivatives have been synthesized with good yield (Table 2), by an esterification reaction of 4-hydroxycoumarin with various benzoyl chlorides (Figure 21).

These new compounds 27 (27b-e) were analyzed by X-ray diffractometry to highlight the crystallographic data that justify their 3D structures [66,67,68,69]. A summary of the crystal data, experimental details and refinement results are given below in Table 4 (Figure 22 - Figure 25).

Table 2. Microwave synthesis yields of compounds 26

Figure 21. Carboxylate of 4-coumarinyl synthesis using HSAB theory

Table 3. Preparation of 4-coumarinyl carboxylate by HSAB theory

Table 4a. Crystallographic data of compounds 27b-e

Table 4b. Crystallographic data of compounds 27b-e

Figure 22. Ortep structure of compound of 27b

Figure 23. Ortep structure of compound 27c

Figure 24. Ortep structure of compound of 27e

Figure 25. Ortep structure of compound of 27d

4. Photochemical properties

4.1. Absorption characteristics

2-Hydroxychromen-4-one 1, trivially designated 4-hydroxycoumarin 1, represents one of the most widespread and interesting classes of simple coumarins, which can play an important role related to their photochemical properties [61,70,71,72,73]. Recently, 4-hydroxycoumarin and its derivatives have attracted considerable attention for electronic and photonic applications. Ervina Becic et al. [70] studied the absorption characteristics of 4-hydroxycoumarin and its 3-substitute derivatives containing phenyl-prop-2-enoyl group at the 3-position 28 (Figure 26, Table 5), in solvents with different polarity (chloroform and acetonitrile) in regard to the influence of the substitution at the phenyl ring and influence of H⁺ ion concentration. This study also provides a qualitative assessment of the new hydroxycoumarin derivatives as ultraviolet absorbers compared to specified organic UV absorbers such as benzophenone-3 29 (Figure 27) and butylmethoxydibenzoylmethane 30 (Figure 28). Indeed, these compounds are organic UV absorbers that are often used for cosmetics and sun creams. They have wide bands in a wide range of UV spectrum [74]. These 4-hydroxycoumarin derivatives also showed high intensity broad-band UV spectra and good absorption over a wide region of 200-550 nm taking into account the property of substituents, polarity and pH of solvents. According to the results of their studies, these new compounds would be good candidates for UV absorbers.

Figure 26. Structure of compound 28

Figure 27. Structure of compound 29

Figure 28. Structure of compound 30

Table 5. Chemical structure of synthesized molecules 28a-b

4.2. Fluorescence Properties

Most coumarin derivatives possess good fluorescent properties, and as such are used as fluorescent markers and dyes for use in analyses, stains and clinical use [73,75]. A number of hydroxycoumarins have been synthesized and explored the possibility of their application to electro-optic materials, such as laser dyes, fluorescent probes or labels, solar collector systems, organic scintillators and photoelectronic sensitizers [75,76]. Specifically, 4-hydroxycoumarins are widely used due to their high emission yields, photo stability, extended spectral range and good solubility in various solvents [61,76]. Djandé et al.[61] studied the fluorescence of series of the new O-acyl derivatives of 4-hydroxycoumarin 27a-27e in liquid medium with acetonitrile as solvent. From this investigation it appears that all the compounds 27 synthesized by considering the substitutes R with variable electron donation capacity, have a considerable fluorescence emission with a wavelength ranging from 372 to 394 nm (Table 6). (Coumarin-4-yl)-4-dimethylaminobenzoate (compound 27e) showed the most intense fluorescence (Figure 29).

Table 6. Excitation wavelengths (λex), emission wavelengths (λem) and fluorescence intensities (IF)

4.3. Photoacid Properties

Photo-acids are generally hydroxyaryl compounds with low acidity in the basic state, while in their first electronic state they are much stronger acids. According to the pKa*, the pKa in the excited state, there are strong and weak photo-acids [77]. The photoacidity of hydroxycoumarins, particularly 7-hydroxycoumarin, is reportedly used for resistance to mould, fungal and bacterial infections by plants [78]. Luís Pinto da Silva et al. [77], in their research on photo-acids, studied 4-hydroxycoumarin using theoretical and experimental methods. Their theoretical studies were in agreement with the results of the experimental studies. It appears that, unlike the 7-hydroxycoumarins previously studied [78], 4-hydroxycoumarin cannot be considered as an active photoacid, and its non-radiative level is much higher than that of 7-hydroxycoumarins in the used solvents.

Figure 29. Fluorescence emission of compound 27e in acetonitrile

5. Conclusion

In this review, we discussed the synthesis, acylation and photochemical properties of 4-hydroxycoumarin 1. The aim of this review is to inform the readers of this review of the current interest of the scientific community in the chemical reactivity and photochemical properties of this compound. With regard to photochemical properties, we mentioned in particular the fact that the structure of the molecule positively influences the behaviour of derivatives, particularly with regard to fluorescence emission. It seems likely that this compound will remain a popular building block for synthetic chemists and that in the future, others innovative developments and applications will be discovered.

References

[1]   | Pierson J. T., Dumetre A., Hutter S., Delmas F., Laget M., Finet J.P., Azas N., Combes S. Synthesis and antiprotozoal activity of 4-arylcoumarins. Europ. J. Med. Chem. 2010, 45 (3): 864-869.
[2]   | Huang L., Yuan X., Yu D., Lee K. H., Chen, C. H. Mechanism of action and resistant profile of anti- HIV-1 coumarin derivatives. Virology 2005, 332 (2): 623-628.
[3]   | Goodman L. S. and Gilman A. The pharmacological basis of therapeutics. 5th Ed., MacMillan, New York, 1975.
[4]   | Kostova I. Synthetic and natural coumarins as cytotoxic agents. Curr. Med. Chem. Anticancer Agents 2005, 5(1): 29-46.
[5]   | Stefanou V., Matiadis D., Melagraki G., Afantitis A., Athanasellis G., Igglessi- Markopoulou O., McKee V., and Markopoulos J. Functionalized 4-Hydroxy Coumarins: Novel Synthesis, Crystal Structure and DFT Calculations. Molecules 2011, 16, 384-402.
[6]   | Dekić B. R., Radulović N.S., Dekić V.S., Vukićević R.D., Palić R.M. Synthesis and antimicrobial activity of new 4-heteroarylamino coumarin derivatives containing nitrogen and sulfur as heteroatoms. Molecules 2010, 15, 2246-2256.
[7]   | Clark G. S. Coumarin. An aroma chemical profile. Perfumer & Flavorist 1995, 20, 23-34.
[8]   | Bedoukian P. Fougère Royale by Houbigant. Perfumer & Flavorist 1993, 18, 35-37.
[9]   | Jaubert J. N., Tapiero C. & Doré J. C. The field of odors: Toward a universal language for odor relationships. Perfumer & Flavorist 1995, 20, 1-16.
[10]   | Bettero A., & Benassi C. A. Determination of coumarin and 6-methylcoumarin in cosmetics by high-performance liquid chromatography. Journal of Pharmaceutical and Biomedical Analysis 1983, 1(2): 229-233.
[11]   | Grundschober F. Coumarin - Determination in alcoholic beverages by high performance liquid chromatography. Zeitschrift fur Lebensmittel-Untersuchung und -Forschung 1997, 204(5): 399.
[12]   | Izquierdo M. E. H., Granados J. Q., Mir V. M., Martinez M. C. L. Comparison of methods for determining Coumarins in distilled beverages. Food Chem. 2000, 70, 251-258.
[13]   | O’Kennedy R., Thornes R. D. Coumarins: Biology, Applications and Mode of Action, Eds., John Wiley and Sons: Chichester, UK, 1997.
[14]   | Liang C., Jiang H., Zhou Z., Lei D., Xue Y., Yao Q. Ultrasound-promoted greener synthesis of novel trifurcate 3-substituted-chroman-2,4-dione derivatives and their drug-likeness evaluation. Molecules 2012, 17, 14146-14158.
[15]   | Key J. A., Koh S., Timerghazin Q. K., Brown A., and Cairo C. W. Photophysical characterization of triazolesubstituted coumarin fluorophores. Dyes and Pigments 2009, 82, (2) 196-203.
[16]   | Ryu H. G., Singha S., Jun Y. W., Reo Y. J. and Ahn K. H. Two-photon fluorescent probe for hydrogen sulfide based on a red-emitting benzocoumarin dye. Tetrahedron Letters 2018, 59(1): 49-53.

[17]  
Murata C., Masuda T., Kamochi Y., Todoroki K., Yoshida H., Nohta H., Yamaguchi M., Takadate A. Improvement of fluorescence characteristics of coumarins: syntheses and fluorescence properties of 6-methoxycoumarin and benzocoumarin derivatives as novel fluorophores emitting in the longer wavelength region and their application to analytical reagents. Chemical and Pharmaceutical Bulletin 2005. 53 (7): 750-758.

[18]   | García-Beltrán O., Cassels B. K., Pérez C., Mena N., Núñez M. T., Martínez N. P., Pavez P., Aliaga M. E. Coumarin-based fluorescent probes for dual recognition of copper(II) and iron(III) ions and their application in bio-imaging. Sensors 2014, 14, 1358-1371.
[19]   | Tasior M., Kim D., Singha S., Krzeszewski M., Ahn K. H., and Gryko D.T. π-expanded coumarins: synthesis, optical properties and applications. Journal of Materials Chemistry C 2015, 3 (7): 1421-1446.
[20]   | Jones G., Griffin S. F., C. Y. Choi, and W. R. Bergmark. Electron donor-acceptor quenching and photoinduced electron transfer for coumarin dyes. Journal of Organic Chemistry 1984, 49 (15): 2705-2708.
[21]   | Traven V. F., Manaev A.V., Safronova O. B., Chibisova T. A. Photoelectron spectra and structure of 4-hydroxycoumarin. J.Electron. Spectrosc. Relat. Phenom. 2002, 122 (1): 47-55.
[22]   | Sousa C. C. S., Morais V. M. F., Matos M. A. R. Energetics of the isomers: 3- and 4-hydroxycoumarin. J. Chem. Thermodyn. 2010, 42(11): 1372-1378.
[23]   | Au N., Rettie A. E. Pharmacogenomics of 4-hydroxycoumarin anticoagulants. Drug Metab. Rev. 2008, 40 (2): 355-375.
[24]   | Joseph K. S., Moser A. C., Basiaga S. B. G., Schiel J. E., Hage D. S. Evaluation of alternatives to warfarin as probes for Sudlow site I of human serum albumin. J. Chromatogr. A 2009, 1216 (16): 3492-3500.
[25]   | Vukovic N., Sukdolak S., Solujic S., Niciforovic N. Substituted imino and amino derivatives of 4-hydroxycoumarins as novel antioxidant, antibacterial and antifungal agents: synthesis and in vitro assessments. Food Chem. 2010, 120 (4): 1011-1018.
[26]   | Chohan Z. H., Shaikh A. U., Rauf A., Supuran, C. T. Antibacterial, antifungal and cytotoxic properties of novel N-substituted sulfonamides from 4-hydroxycoumarin. J. Enzym. Inhib. Med. Chem. 2006, 21, 741-748.
[27]   | Luchini A. C., Rodrigues-Orsi P., Cestari S. H., Seito L. N., Witaicenis A., Pellizzon C. H. Intestinal Anti-inflammatory Activity of Coumarin and 4-Hydroxycoumarin in the Trinitrobenzenesulphonic Acid Model of Rat Colitis. Biol. Pharm. Bull. 2008, 31, 1343-1350.
[28]   | Dong Y., Nakagawa-Goto K., Lai C., Morris-Natschke S., Bastow K., Lee K. Antitumor agents 278. 4-Amino-2H-benzo[h]chromen-2-one (abo) analogs as potent in vitro anticancer agents. Bioorg. Med. Chem. Lett. 2010, 20, 4085-4087.
[29]   | Stern P., Dezelic M., Kosak R. Analgesic & antipyretic effects of vitamin K & dicumarol with special reference to 4-hydroxycoumarin. Arch. Exp. Pathol. Pharmakol 1957, 232 (1): 356-359.
[30]   | Chiang C. C., Mouscadet J. F., Tsai H. J., Liu C.T., Hsu L.Y. Synthesis and HIV-1 integrase inhibition of novel bis- or tetracoumarin analogues. Chem. Pharm. Bull. 2007, 55 (12): 1740-1743.
[31]   | Cravotto G., Tagliapietra S., Cappello R., Palmisano G., Curini M., Boccalini M. Long-chain 3-acyl-4- hydroxycoumarins: Structure and antibacterial activity. Arch. Pharm. Chem. Life Sci. 2006, .339, 129-132.
[32]   | Shah V. R., Bose J. L., Shah R. C. New Synthesis of 4-Hydroxycoumarins. J.Org .Chem. 1960, 25, 677.
[33]   | Abdou M. M., El-Saeed A. R., Bondock S. Recent advances in 4-hydroxycoumarin chemistry. Part 1: Synthesis and reactions, Arabian Journal of Chemistry (2015) in press.
[34]   | Naveen S., Adlakha P., Upadhyay K., Shah A., Anandalwar S. M., Prasad, S., Crystal structure of 3-nitro-4-hydroxycoumarin. X-Ray Struct. Anal. Online 2006, 22 (4): x103-x104.
[35]   | Gao W.T., Hou W. D., Zheng M. R., Tang L. J. Clean and convenient one-pot synthesis of 4-hydroxycoumarin and 4-hydroxy- 2-quinolinone derivatives. Synth. Commun. 2010, 40 (5): 732-738.
[36]   | Park S. J., Lee J. C., Lee K. I. A facile synthesis of 4-hydroxycoumarin and 4- hydroxy-2-quinolone derivatives. Bull.Korean Chem. Soc. 2007. 28 (7): 1203-1205.
[37]   | Zhi Qiang D., Shi J. B., Song B. A., Liu X. H. Novel 2 Hchromenderivatives: design, synthesis and anticancer activity. Roy. Soc. Chem. Adv. 2014. 4 (11), 5607-5617.
[38]   | Jung J. C., Jung Y. J., Park O. S. A. Convenient one-potsynthesis of 4-hydroxycoumarin, 4-hydroxythiocoumarin and 4-hydroxyquinolin-2(1H)-one. Synth. Commun 2001, 31 (8): 1195-1200.
[39]   | Kasabe A., Mohite V., Ghodake J., Vidhate J. Synthesis, characterization and primary antimicrobial, antifungal activityevaluation of schiff bases of 4-chloro-(3-substituted-phenylimino)-methyl-[2H]-chromene-2-one. E-J. Chem. 2010, 7 (2): 377-382.
[40]   | Payne S. L., Rodriguez-Aristegui S., Cano C., Golding B. T., Hardcastle I. R., Griffin, R. J., Bardos J., Peacock M., Parveen N. Mapping the ATP-binding domain of DNA-dependentprotein kinase (DNA-PK) with coumarin- and isocoumarinderivedinhibitors. Bioorg. Med. Chem. Lett 2010, 20 (12): 3649-3653.
[41]   | Zhao P. L., Wang L., Zhu X. L., Huang X., Zhan, C. G., Wu, J. W., Yang, G. F. Subnanomolar inhibitor of cytochrome bc1complex designed by optimizing interaction with conformationallyflexible residues. J. Am. Chem. Soc. 2010, 132 (1): 185-194.
[42]   | Sosnovskikh Ya. V., Kutsenko V. A., and Ovsyannikov S. I. Condensation of 2- hydroxyacetophenones with trichloroaeetonitrileas a route to 2-trichloromethylchromones and 4-hydroxycoumarins. Russian Chemical Bulletin, Fol. 2000, 49(3): 478-481.
[43]   | Liao Y.-X., Kuo P-Y., Yang D.-Y. Efficient synthesis of trisubstituted [1]benzopyrano [4,3-b] pyrrol-4(1H)-one derivatives form 4-hydroxycoumarin. Tetrahedron Letters 2003, 44, 1599-1602.
[44]   | Ganguly N.C., Dutta S., Datta M. Mild and efficient deprotection of allyl ethers of phenols and hydroxycoumarins using a palladium on charcoal catalyst and ammonium formate. Tetrahedron Lett. 2006, 47 (32): 5807-5810.
[45]   | Nawghare B. R., Sakate S. S., Lokhande P. D. A new methodfor the facile synthesis of hydroxylated flavones by using allylprotection. J. Heterocyclic Chem. 2014, 51 (2): 291-302.
[46]   | Jung J. C., Kim J. C., Park O. S. Simple and cost effective syntheses of 4-hydroxycoumarin. Synth. Commun. 1999, 29 (20): 3587-3595.
[47]   | Kawata H., Kumagai T., Niizuma S. Photooxygenationof chromone-2-carboxylic Acid: identification of ketohydroperoxideusing a chemiluminescence technique. Chem. Lett. 1999, 9, 985-986.
[48]   | Tapase B. A, Suryawanshi V. S., Shinde D N., Shinde B. D. Solvent Free Microwave Assisted O - Alkylation and Acylation of 4 - Hydroxy Coumarin. Bull. Environ. Pharmacol. Life Sci. 2012, 1 (7) : 30 - 33.
[49]   | Dupont R., & Cotelle P. Reaction of aryl-2-hydroxypropenoic derivatives with boron tribromide. Tetrahedron Letters 2001, 42(4): 597-600.
[50]   | AL-AYED A. S. Synthesis of New Substituted Chromen[4,3-c]pyrazol-4-ones and Their Antioxidant Activities. Molecules 2011, 16(12): 10292 - 10302.
[51]   | Cravotto G., Tagliapietra S., Cappello R., Palmisano G., Currini M. and Bocalini M. Long-Chain 3-Acyl-4-hydroxycoumarins: Structure and Antibacterial Activity. Archiv der. Pharmazie 2006, 338(3): 129-132.
[52]   | Cravotto G., Balliano G., Tagliapietra S., Oliaro-Bosso S., Nano G. M. Novel squalene-hopene cyclase inhibitors derived from hydroxycoumarins and hydroxyacetophenones. Chem. Pharm. Bull. 2004a 52 (10): 1171-1174.
[53]   | Cravotto G., Balliano G., Tagliapietra S., Palmisano G., Penoni A. Umbelliferone aminoalkyl derivatives, a new class of squalene-hopene cyclase inhibitors. J. Med. Chem. 2004b, 39 (11): 917-924.
[54]   | Stadlbauer W., Hojas G. Ring closure reactions of 3-arylhydrazonoalkyl-quinolin-2-ones to 1-aryl-pyrazolo[4,3-c]quinolin-2-ones. J. Heterocycl. Chem. 2004, 41(5): 681-690.
[55]   | Kravchenko D.V., Chibisova T. A., Traven V. F. Intermolecular character of the Fris rearrangement in the series of acyloxycoumarins. Russ. J. Org.Chem. 1999, 35 (6): 899-909.
[56]   | Traven V. F., Manaev A.V., Safronova O. B., Chibisova T. A., Lysenko K. A., Antipin M. Y. Electronic structure of π systems: XVIII. Photoelectron spectrum and crystal structure of 3-acetyl-4-hydroxycoumarin. Russ. J.Gen. Chem. 2000, 70(5): 798-808.
[57]   | Dholakia V. N., Parekh M. G., Trivedi N. K., Improved and rapid synthesis of new coumarinyl chalcone derivatives and their antiviral activity . Aust. J. Chem. 1968, 22, 345-2347.
[58]   | Akoun A., Djande A., Sessouma B., Saba A. and Kakou-Yao R. 4-[(4-Chlorophenyl)(hydroxy)methylidene]isochromane-1,3-dione. Acta Cryst., E 67, 2011: 20011, 2269-2270
[59]   | Akoun A., Djande A., Kakou-Yao R., Saba A. and A. J. Tenon. 2-Oxo-2H-chromen-4-yl 4-methylbenzoate. Acta Cryst. E69, 2013, 1081-1082.
[60]   | Rad-Maghadam K., Mohseni M., A Route to the Synthesis of Novel Coumarins. Monatshefte fur chemie 2004, 135 (7): 817-821.
[61]   | Djandé A., Cissé L., Yoda J., Kaboré L. and Duvernay F. Synthesis and fluorescence study of a series of 4-hydroxycoumarin o-acylation derivatives. world journal of pharmacy and pharmaceutical sciences 2019, 8 (1):116-130.
[62]   | Saba A. Recherche dans la série des sels de benzopyrylium: Synthèse et étude de la structure des sels de 2-benzopyrylium. Thèse d’Etat 1996, Université de Ouagadougou, Burkina Faso.
[63]   | Saba A., Sib F. S., Faure R. and Aycard J. P. NMR and AM1 study of the tautomeric equilibrium of isochroman-i,3-diones. Spectrosc. Lett. 1996, 29(8): 1649-1657.
[64]   | Pearson R. G. Hard. Soft Acids and Bases J. Amer. Chem. Soc. 1963, 85, 3583.
[65]   | Djandé A., Cisse L., Kaboré L., Saba A., Tine A. and Aycard J. P. Synthesis and fluorescence properties of 4-acylisochroman-1,3-diones. Heterocyclic communications 2008 14(4): 237-244.
[66]   | Abou A., Djandé A., Kakou-Yao R., Saba A. and Tenon A. J. 2-Oxo-2H-chromen-4-yl 4-methylbenzoate. Acta Cryst., E69, 2013, o1081-o1082.
[67]   | Abou A., Sessouma B., Djandé A., Saba A. and Kakou-Yao R. 2-Oxo-2H-chromen-4-yl 4-tert-butylbenzoate. Acta Cryst., E68, 2012, o537-o538.
[68]   | Abou A., Djandé A., Danger G., Saba A. and Kakou-Yao R. 2-Oxo-2H-chromen-4-yl 4-methoxybenzoate. Acta Cryst., E68, 2012, o3438-o3439.
[69]   | Abou A., Djandé A., Sessouma B., Saba A. and Kakou-Yao R. 2-Oxochromen-4-yl 4-(dimethylamino) benzoate. Acta Cryst., E67 (2011): o2269-o2270.
[70]   | Becic E., Sober M., Imamovic B., Zavrsnik D., Spirtovic-Halilovic S. UV/VIS absorption and fluorescence spectroscopic study of some 3-substituted derivatives of 4-hydroxycoumarin. Pigment & Resin Technology 2011, 40 (5): 292-297.
[71]   | Al-Haiza M., Mostafa M. S. and El-Kady M. Y. Synthesis and biological evaluation of some new coumarin derivatives. Molecules 2003, 8 (2): 275-86.
[72]   | Fylaktakidou K. C., Hadjipavlou-Litina D. J., Litinas K. E.and Nicolaides D. N. Natural and synthetic coumarin derivatives with anti inflammatory/antioxydantactivities, Current Pharmaceutical Design 2004, 10 (30): 3813-33.
[73]   | Al-MajedyY. K., Al-Amiery A. A., Kadhum A. A. H., Mohamad A. B. 4-Hydroxycoumarins as New Fluorescent Compounds: Synthesis and Characterization. American Journal of Chemistry 2015, 5 (3A): 48-51.
[74]   | Salvador A. and Chisvert A. Analysis of Cosmetic Products, Elsevier, Amsterdam, (2007):83-121.
[75]   | Sosso S., Yoda J., Djandé A., Coulomb B. (Coumarin-3-yl)-benzoates as a Series of New Fluorescent Compounds: Synthesis, Characterization and Fluorescence Properties in the Solid State. American Journal of Organic Chemistry 2018, 8(2): 17-25.
[76]   | Gikas E., Parissi-Poulou M., Kazanis M. and Vavagiannis A., Properties of a new fluorescent coumarin derivatization reagent employing molecular modelling techniques. Journal of Molecular Structure: THEOCHEM 2005, 724 (1-3): 135-42.
[77]   | Luís Pinto da Silva, Ron Simkovitch, Dan Huppertb, Joaquim C.G. Esteves da Silva. Combined experimental and theoretical study of the photochemistry of 4- and 3-hydroxycoumarin. Journal of Photochemistry and Photobiology A: Chemistry 338 (2017): 23-36
[78]   | Simkovitch R., Huppert D. Photoprotolytic processes of umbelliferone and proposed function in resistance to fungal infection. J. Phys. Chem. 2015, B 119, 14683-14696.