Synthesis and Spectroscopic Study of Coumarin Derivatives

Five new coumarin amide derivatives were synthesized with coupling reagent,the structures of which were characterized by IR,1H NMR,13C NMR,MS and element analysis.Their spectral properties were studied in dichloromethane,in N,N-dimethylformamide（DMF） and in solid state.Solvent polarity has less influence on the UV-Vis maximum absorption at about 430 nm.The maximum emission wavelengths change from 464 nm to 474 nm in dichloromethane,from 476 nm to 482 nm in DMF and from 521 nm to 548 nm in solid state,respectively.The fluorescence intensities of compounds 8 and 9 were extremely strong in solvents or in solid state.Compounds 8 and 9 exhibited high fluorescenct quantumn yields in solution compared to compounds 4 ＂7.The fluorescence lifetimes of all the compounds in solvents were measured.

Synthesis,Crystal Structure and Photoluminescence of Ethyl Coumarin-3-carboxylate Derivatives

The ethyl coumarin-3-carboxylate （1） and its two derivatives, ethyl 7-methoxy-2- oxo-2H-chromene-3-carboxylate （2） and ethyl 7-（3-methylbut-2-enyloxy）-2-oxo-2H-chromene-3- carboxylate（3）, were synthesized, characterized and their UV-vis spectra and photoluminescence were investigated. Compound 2 crystallizes in the monoclinic system with space group C2/c, a = 25.884（4）, b = 6.8365（11）, c = 13.816（2） A, β = 104.876（2）°, V= 2362.9（7） A3, Z = 8, Dc= 1.396 g/cm3, Mr. = 248.23, F（000） = 1040 and g = 0.108 mm-1. Compound 3 crystallizes in the monoclinic system with space group P21/c, a = 15.685（6）, b = 8.373（3）, c = i3.063（5） A, β = 111.862（6）°, V= 1592.2（10） A3, Z = 4, Dc = 1.261 g/cm3, M,.= 302.31, F（000） = 640 and p = 0.093 mm^-1. Both the absorption and emission of the two derivatives were stronger than that of ethyl coumarin-3-carboxylate due to the larger conjugation of their electron donor group moiety at the 7-position. Under ultraviolet light excitation, the two derivatives exhibit strong blue-violet emission.

Synthesis of some new fused coumarin derivatives

2-Hydrazino-4-hydroxy-5H-[1]-benzopyrano-[4,3-d]-pyrimidin-5-one (3) was prepared via condensation of 2 with hydrazine hydrate. Treatment of 3 with methylene chloride, ethyl chloroformate, ethyl chloroacetate and benzaldehyde yielded the corresponding 2 - ( substituted ) hydrazino - 4 -hydro-xy-5H-[1]-benzopyrano-[4,3-d]-pyrimidin-5-one (4, 5, 6, and 10), followed by cyclization of 4, 5 and 6 with dimethyl formamide and fused sodium acetate under reflux, while compound 10 was cyclized with bromine and sodium acetate in acetic acid. Compound 3 reacted with β-(toloyl) acrylic acid, ethyl α-cyano-p-methoxycinnamate, diethyl malonate and acetyl chloride affording the corresponding 2-(substituted) hydrazino-4-hydroxy-5H-[1]-benzopyrano-[4,3-d]-pyrimidin-5-one (12, 13, 14, 15 and 16).

Synthesis and comparative study of reactivities of δ-lactone,estor group and oxazinone ring in coumarin derivatives towards carbon or nitrogen nucleophiles

Condensation of methyl 7-methylcoumarin-4-acetate(2)with primary amines and with an- thranilic acid gave 7-methyl-2-oxo-N-aryl-2H-[1]-benzopyran-4--acetamide(4a—d)and(7),respectively. Compound 7 underwent cyclization to give 2-(7-methyl-2-oxo-2H-[1]-benzopyran-4-yl)-methyl-4H-3,1- benzoxazin-4-one(3).The reaction of 3 with aromatic amines gave the corresponding quinazolone derivatives 5 which tautomerises to the thermodynamically more stable isomer 6,whereas its reaction with Grignard reagents and aromatic aldehydes gave 8a,8b,and 9a,9b,respectively.

Conversion of 3-Carbethoxy-4-methyl Coumarin Derivatives into Several New Annelated Coumarin Derivatives

The reaction of ethyl esters of 4-methyl-2-oxo-2H-l-benzo (naphtho)pyran-3-carboxylic acids (1) with aromatic aldehydes in the presence of piperidine yielded4-styryl-3-carboxami-dopiperidyl coumarin derivatives 4. The reaction of hydrazine hydrate with 1gave acetophenone hydrozone derivatives 5 and acetophenone azine derivatives 6. The reaction of 1with primary amines afforded compounds 7―9. And the treatment of la with Grignard reagents afforded3-aroyl-4-methyl coumarin derivatives 10.

Synthesis,Structure and Fluorescence Study of 3-Bromo-7-methyloxy-4-methylcoumarin

Coumarin derivative 3-bromo-7-methyloxy-4-methylcoumarin（C11H9BrO3） was synthesized and characterized by FT-IR,1H NMR spectra,and thermal analysis.The crystal structure was determined by X-ray single-crystal diffraction.The title compound crystallizes in the mono-clinic system,space group P21/n,with a = 7.770（16）,b = 12.501（3）,c = 10.627（2）,β = 98.46（3）°,Mr = 269.09,V = 1021.0（4） 3,Z = 4,Dc = 1.751 g/cm3,μ = 4.008 mm-1,F（000） = 536,R = 0.0650 and wR = 0.1463.The optimization of the title compound was obtained by quantum chemical method at the SVWN5/6-31G＊＊ level.In the structure,the measured angles of the crystal structure are similar to those calculated,while the measured bond lengths are shorter than the calculated values due to the crystal field which functions to the molecule.The title compound also shows good fluorescent behaviors and good linear relationship with the equal concentration gradient in methanol.

Photocycloaddition of (4-methyl-7-coumarinyl) Oxyacetic Acid Propanediol Diester and X-ray Crystal Structure of Product

The photocycloaddition of (4-methyl-7-coumarinyl) oxyacetic acid propanediol diester 1 (C_27H_24O_10) in chloroform produced a single product 2 characterized to be syn head-tail. Crystal structure of 2 has been determined by X-ray diffraction analysis. The crystal belongs to orthorhombic system, space group Pbca, with cell parameters a=10. 745(5), b= 13. 443(4), c=33. 358(9) A, V=4791 (5) A￣3, M_r=508. 49,Z= 8, D_c=1. 41 g/cm￣3, μ= 1. 015 cm￣-1, F(000)=1064. The final R=0. 065 for 1587 observed reflections. Compound 2 has a large ring resulted from [2+2] photocycloaddition. The four-member ring of 2 has poor coplanarity, the two diagonal atoms of four-member ring are above the least-squares plane, and another diagonal atom couple is below the least-squares plane, the deviations of two couples are approximately equal.

Recent advances in the biosynthesis of coumarin and its derivatives

Coumarin and its derivatives,presenting in many organisms(plants,fungi,and bacteria),are critical metabolites composed of fused benzene andα-pyrone rings.With unique biological and chemical properties,coumarin derivatives possess great technological potential in the agrochemicals,pharmaceuticals,food,and cosmetic industries.The increasing demand for coumarin derivatives accelerates the research in biological and chemical synthesis to provide stable and scalable sources of coumarins.However,the complex structures and unknown pathways have limited the progress in the biosynthesis of coumarin derivatives.Here,we summarize recent developments and provide a detailed analysis of coumarin derivative biosynthetic pathways in different organisms.

Synthesis,Crystal Structure and Characterization of3-Ethyl-3,4,4a,10a-tetrahydro-2H-1,5-dioxa-3-aza-phenanthren-6-one:C_(13)H_(13)NO_3

3-Ethyl-3,4,4a, 10a-tetrahydro-2H- 1,5-dioxa-3-aza-phenanthren-6-one （C13H13NO3, Mr = 231.24） was synthesized and characterized by FT-IR, H NMR spectra, and thermal analysis. The crystal structure was determined by X-ray single-crystal diffraction. It crystallizes in methanol. The crystal is of orthorhombic system, space group Pbca with a = 8.9250（18）, b = 12.605（3）, c = 20.552（4） A, Z = 8, V = 2312.1（8） A3, Dc = 1.329 mg/m3, p = 0.095 mm-, F（000） = 976, R = 0.0583 and wR = 0.1340. Thermal analysis reveals that it is stable below 100 C. Fluorescence spectra analysis shows that its fluorescence intensity is twice as that of 7-hydroxylcoumarin in methanol solution with the same concentration.

Synthesis and Crystal Structure of 8-Methyl-7-(3-nitrophenyl)-10-phenyl-10,11-dihydrochro-meno[4,3-b]pyrazolo[4,3-e]pyridin-6-(7H)-one

The title compound（C26H18N4O4） has been synthesized via a three-component reaction and it was characterized by means of IR and 1H NMR.Its crystal and molecular structures were determined by X-ray diffractometry.It belongs to the triclinic system,space group P1 with a = 7.7288（15）,b = 11.168（2）,c = 12.645（3） ,α = 107.02（3）,β = 90.85（3）,γ = 101.93（3）°,V = 1017.9（3） 3,Mr = 450.44,Z = 2,Dc = 1.470 g/cm3,λ = 1.54178 ,μ = 0.836 mm-1,F（000） = 468,the final R = 0.0488 and wR = 0.1180.A total of 11903 reflections were collected,of which 3642 were independent（Rint = 0.0377） and 3025 were observed with I 2σ（I）.

Lanthanide complexes with β-diketones and coumarin derivates:synthesis,thermal behaviour,optical and pharmacological properties and immobilisation

The paper presents the results of the synthesis of complexes of the ty pe Eu(DBM) 3 and Eu(DBM) 3·Q(DBM-dibenzoylmethane,Q-1,10-phenantroline or 4,7-d iphenyl-1,10-phenantroline) and of Tb-and Nd-complexes with the newly-synthesis ed coumarin derivates 3,3’-[(4-chlorphenyl) methylene) bis(4-hydroxy-2H-chromen-2-one) ,3,3’-[(3,5-dimethoxy-4-hydroxy) methylene) bis(4-hydroxy-2H-chromen-2-one) ,etc. Elemental and thermogravimetric analysis,IR,UV,NMR and fluorescence spe ctroscopy and X-ray analysis were applied for characterisation of the complexes. Some peculiarities of the synthetic procedures for both types of complexes were discussed and the influence of the synthetic approach,pH of the reaction mediu m,temperature of synthesis and drying of the complexes on the composition,stab ility and optical properties was reported. The immobilisation of the complexes i n thin films based on sol-gel produced SiO2 and on polymethylmethacrylate was st udied. The optimal conditions for preparation of the matrices(composition of th e starting system,temperature and time of sol aging,etc.) were recommended. Th e film morphology was evaluated by fluorescence,scanning electron and atomic fo rce microscopy. The interaction of the lanthanide ions with the matrices and the influence of their nature,the effect of the in-situ polymerisation and other f actors on photoluminescent excitation and emission spectra and excited state lif e-times of the complexes were followed. The effect of the second ligand on the p hotoluminescence properties of the immobilised diketonates was further elucidate d. Processes involved in the thermal decomposition of the complexes and microcom posites produced on their base were proposed. Preliminary results on the pharmac ological properties of the coumarin complexes reported showed unambiguously high er cytotoxicity of the Nd complex in comparison with that of the respective ligand.

Chemical behaviours of 3-[1'-chloro-3'-(2"-phenyl-1",3"-oxazol-5"-one-4"-ylidene)propen-l'-yl]coumarin towards some nucleophilic reagents

The chemical behaviours of 3-[1'-chloro-3'-(2'-phenyl-1',3'-oxazol-5'-one-4'-ylidene)-propen-1'-yl]coumarin towards nucleophilic reagents (such as hydrolysis,aminolysis,hydroxyl-aminolysis,methanolysis and hydrazinolysis) were described.