An efficient synthesis of furanocoumarins

Zubı́a, Eva; Luis, F. Rodriguez; Massanet, Guillermo M.; Collado, Isidro G.

doi:10.1016/s0040-4020(01)92200-8

Cited by 55 publications

(35 citation statements)

References 20 publications

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“…Compounds 2-20 were synthesised in the laboratory according to methods previously reported in the literature: 4-methylcoumarin (2), 7 7-methylcoumarin (3), 7 4-hydroxycoumarin (4), 7 7-hydroxycoumarin (5), 8 4,7-dihydroxycoumarin (6), 7 5,7-dihydroxycoumarin (7), 9 4-hydroxy-3-methylcoumarin (8), 7 3,6-dimethyl-4-hydroxycoumarin (9), 7 7,8-dihydroxy-4-methylcoumarin (10), 7 7-methoxycoumarin (11), 10 5,7-dimethoxycoumarin (12), 10 4-hydroxy-7-methoxycoumarin (13), 7 4-hydroxy-7-methoxy-3-methylcoumarin (14), 7 7-hydroxy-6-methoxycoumarin (15), 11 7-chlorocoumarin (16), 8 6-bromo-7-hydroxycoumarin (17), 12 6-bromo-7-methoxycoumarin (18), 12 7-hydroxy-8-iodocoumarin (19), 13 8-iodo-7-methoxycoumarin (20). 14 -5,7-dimethoxycoumarin (22).…”

Section: Chemicalsmentioning

confidence: 99%

A study of the electrospray ionisation of selected coumarin derivatives and their subsequent fragmentation using an ion trap mass spectrometer

Concannon¹,

Ramachandran²,

Smyth³

2000

Rapid Commun. Mass Spectrom.

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Section: Chemicalsmentioning

confidence: 99%

A study of the electrospray ionisation of selected coumarin derivatives and their subsequent fragmentation using an ion trap mass spectrometer

Concannon¹,

Ramachandran²,

Smyth³

2000

Rapid Commun. Mass Spectrom.

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“…11 This compound has been isolated from a number of plant sources and has been the subject of some recent syntheses. 12, 13 Thus the commercially available 7-hydroxycoumarin 49 was formylated with complete regioselectivity, though in low yield, by the Duff reaction to give the 8-formyl compound 50. 14 Allylation under standard conditions gave 51, which was subjected to a Wittig reaction to give the propenoate precursor 52 which was purified by chromatography on silica.…”

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confidence: 99%

Synthesis of fused furans by gas-phase pyrolysis of 2-allyloxyarylpropenoic esters 1

Black¹,

Cadogan²,

McNab³

et al. 1997

J. Chem. Soc., Perkin Trans. 1

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Flash vacuum pyrolysis of 2-allyloxypropenoic esters (e.g. 7) gives benzo[b]furans (e.g. 32) in synthetically useful yields by sequential generation of a phenoxyl radical, cyclisation and ejection of the carboxylic ester function as a free radical leaving group. The method is compatible with a range of substituents on either the benzene ring or the propenoate chain, and is particularly effective for 2-substituted benzo[b]furans. The natural products 5-methoxybenzo[b]furan 1 and angelicin 2 have been synthesised in three and four steps respectively from commercially available starting materials by this route. Related cyclisations to give naphtho[2,1-b]furan 40 were complicated by competitive formation of naphtho-[2,1-b]pyran-3-ones (e.g. 41 and 42), but the yield of the required product could be optimised by the choice of the radical precursor. Annelation of a furan ring onto a thiophene is also possible by this method, but lower yields are obtained in such pyrolyses.In earlier papers we have reported application of the technique of flash vacuum pyrolysis (FVP) to the gas-phase generation of aryloxyl radicals, and their reactions with adjacent aromatic systems. 2,3 These processes are often dominated by hydrogen abstractions, and relatively small amounts of useful cyclisation products are formed. In extending this work to the properties of aryloxyls with adjacent alkene systems, it became apparent at an early stage that the carboxylic ester function behaves as a specific and highly efficient radical leaving group under these conditions, leading to a useful synthetic route to benzo[b]-furans. 1 We now present full details of this work, and its extensions, which have led to concise syntheses of the natural products 5-methoxybenzo[b]furan 1 and angelicin 2. The results of preliminary attempts to annelate a furan ring onto fivemembered heterocyclic systems are also reported.As in our previous work, 2,3 we have employed O-allyl or Obenzyl ethers as radical generators, made in high yield from the corresponding phenol by treatment with the appropriate bromoalkane in dimethylformamide containing anhydrous potassium carbonate. The alkene function was made from an appropriate carbonyl compound by Wittig or Knoevenagel methodology (Scheme 1). In many cases, the order of the allylation and Wittig steps was unimportant, though in practice 2-allyloxybenzaldehyde 3 was used to make the Wittig products 4 and 14 (obtained in low, but unoptimised yields) and the Knoevenagel products 5, 19 and 20 (61-97%). Compounds 5 and 20 were made from the appropriate active methylene compound using piperidinium acetate catalyst, but it proved necessary to use more vigorous conditions (titanium tetrachloridepyridine) for the synthesis of the diester 19. The precursors 7, 9, 11, 13, 16 and 18 were made by allylation of the phenols 6, 8, 10, 12, 15 and 17 (80-100%) respectively, which were themselves made by Wittig reactions with salicylaldehydes, to give predominantly-often exclusively-the E-isomers (75-90%). 4 The alkoxynaphthols 22-24 and 26 we...

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“…[18][19][20][21] When coumarin 4 was dissolved in 5 % aqueous sodium hydroxide (step c), followed by direct iodination with iodine (step d) and lactone ring closure with hydrochloric acid (step e), nearly quantitative yield of the desired coumarin 1 was obtained.…”

Section: Resultsmentioning

confidence: 99%

Fluorogenic Transformations Based on Formation of CC Bonds Catalyzed by Palladium: An Efficient Approach for High Throughput Optimizations and Kinetic Studies

2008

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Abstract:We have developed novel fluorogenic transformations based on formation of C À C bonds catalyzed by palladium using iodocoumarin 1 as a model aryl iodide, where fluorescence is quenched completely due to effects of the heavy, polarizable iodine atom. Substitution of the iodine atom for the carbon using Sonogashira, Suzuki-Miyaura and Heck couplings results in a dramatic fluorescence enhancement. This approach has been used successfully for the optimization of reaction conditions and kinetic studies in high throughput format.

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An efficient synthesis of furanocoumarins

Cited by 55 publications

References 20 publications

A study of the electrospray ionisation of selected coumarin derivatives and their subsequent fragmentation using an ion trap mass spectrometer

A study of the electrospray ionisation of selected coumarin derivatives and their subsequent fragmentation using an ion trap mass spectrometer

Synthesis of fused furans by gas-phase pyrolysis of 2-allyloxyarylpropenoic esters 1

Fluorogenic Transformations Based on Formation of CC Bonds Catalyzed by Palladium: An Efficient Approach for High Throughput Optimizations and Kinetic Studies

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