Coumarin dihydro

Coumarin, 3,4-dihydro-4-phenyl-synthesis, 3, 848 Coumarin, 6,7-dihydroxy-molecular structure, 3, 622 Coumarin, 7,8-dihydroxy-molecular structure, 3, 622 Coumarin, 6,7-dimethoxy-mass spectra, 3, 610... 

Coumarin, 7-diethylamino-4-methyl-fluorescence, 3, 879 Coumarin, dihydro-chroman synthesis from, 3, 785 4H-chromene synthesis from, 3, 765 coumarin synthesis from, 3, 810 mass spectra, 2, 23 synthesis, 3, 848 Coumarin, 3,4-dihydro-4,4-disubstituted synthesis, 3, 754... 

Coumarin, 7-diethylamino-4-methy 1-fluorescence, 3, 879 Coumarin, dihydro-... 

Miscellaneous Reactions. Palladium dba has been employed as a catalyst for effecting various annulation reactions. Mediumsized nitrogen heterocycles have been prepared from allenes and amino alkenyl hahdes in the presence of a Pd(dba)2/PPh3 catalyst system. 1,3-Dienes can be converted to benzofuran derivatives upon reaction with o-iodoacetoxy arenes and this reaction has been applied in the synthesis of new coumarins. Dihydro-quinoxalines and quinoxalinones have been obtained via reductive annulation of nitro enamines (eq 26). ... 

Coumarin, 4-alkyl-3-phenyl-3,4-dihydro- H NMR, 3, 583 Coumarin, 3-amino-synthesis, 3, 806 Coumarin, 7-amino-application... 

Compound 24a was also obtained in 17% yield by heating of 4-hydroxy-3-nitrocoumarin 27 [12] with hydrazine hydrate in ethanol. A similar reaction of 27 with methylhydraine in boiling ethanol did not afford 24b because of the decomposition of the starting coumarin. However, when 27 was treated with methylhydrazine at room temperature for 24 h without solvent, the ring-opened methylhydrazine adduct 28 (36% yield) and 1,2-dihydro-5-(2-hydroxyphenyl)-l-methyl-4-nitro-3H-pyrazol-3-one 26 (ll%yield) were... 

Wakselman, M. Hamon, J.-F. Vilkas, M. Lactones phenoliques halomethylees, inhibi-teurs bifonctionnels de proteases II. Preparation de derives halomethyles de la dihydro-3,4-coumarine et de la benzofuranone-2. Tetrahedron 1974, 30, 4069-4078. 

Mor, A. Maillard, J. Favreau, C. Reboud-Ravaux, M. Reaction of thrombin and proteinases of the fibrinolytic system with a mechanism-based inhibitor, 3,4-dihydro-3-benzyl-6-chloromethyl-coumarin. Biochim. Biophys. Acta 1990, 1038, 158-163. 

Formica sanguinea W-HG Trail following antennal responses 3,4 - Dihydro - 8 -hydroxy- 3,7- dim e thyliso-coumarin 120 3-ethyl-3,4-dihydro-8-hydroxy-7-methylisocoumarin 130 [172,173]... 

Lasius fuliginosus W-HG Trail following antennal responses (3R)-(-)-3,4-Dihydro-8-hydroxy-3-methyliso-coumarin 129 2,3-dihydro-3,5-dihydroxy-6-methyl-4H-pyran-4-one 134 [175]... 

The compound 7-(4-chloro-benzyl)-2-(4-chloro-phenyl)-3,8a-dihydro-pyridazino[4,3-( ][l,3,4] thiadiazin-8-one 42 has been reported to be active against Bacillus Escherchia coli, Staphylococcus aureus, and Pseudomonas aeruginosa by a serial dilution method <2001IJB475>. Triazino-thiadiazines 24f, 25b, 25c, and 25f <2002IJH287> have been reported to be active against S. aureus-, sydnone derivatives of triazino-thiadiazine 24f <2002IJH287> are more reactive than coumarin derivatives. 

Formation of mixtures of the above type, which is common with internal olefins, do not occur with many functionalized alkenes. Thus, tertiary cinnamates and cinnamides undergo cycloadditions with benzonitrile oxides to give the 5-Ph and 4-Ph regioisomers in a 25-30 75-70 ratio. This result is in contrast to that obtained when methyl cinnamate was used as the dipolarophile (177). 1,3-Dipolar cycloaddition of nitrile oxides to ethyl o -hydroxycinnamate proceeds regiose-lectively to afford the corresponding ethyl fra s-3-aryl-4,5-dihydro-5-(2-hydro-xyphenyl)-4-isoxazolecarboxylates 36 (178). Reaction of 4-[( )-(2-ethoxycarbo-nylvinyl)] coumarin with acetonitrile oxide gives 37 (R = Me) and 38 in 73% and 3% yields, respectively, while reaction of the same dipolarophile with 4-methoxy-benzonitrile oxide affords only 37 (R = 4-MeOCr>H4) (85%) (179). 

In contrast to the benzoannelated nitrogen heterocycles, only a few kinds of benzoannelated systems without nitrogen have been described (Fig. 3.15). Five-mem-bered rings such as benzo[b]furans (336) [184, 461] and hydrobenzo[b]furans (337) (Scheme 3.41) [337, 462, 463] and six-membered rings like 4H-l-benzopyran-4-ones (4-chromones) (338) and 2H-l-benzopyran-2-ones (coumarines) (339) [96, 464, 465] 2,3-dihydro-4H-l-benzopyran-4-ones (chroman-4-ones) (340) [466] and 3,4-dihydro-lH-2-benzopyrans (isochromans) (341) [444] have been reported. 

Coumaric acid, para Rt ° °, Call Coumarin, iso, 3 4 dihydrO 8 hydroxy-6 mehoxy-d-methyl Rt Call Tiss Coumarin, iso RtDC 59 Cpsmosiin ... 

Dihydro-7-hydroxy-2R, 3R dimethyl-2-[4,8-imethyl-3 (E), 7 -nonadieny 1] -furo[3,2-C]coumarin ... 

Dihydro-7-hydroxy-2S, 3R -dimethyl-3-[4-methyl-5- (4-methy 1-2-furyl) -3(E)-pentenyl]-furo[3,2-C]coumarin Rt AOSZ... 

Dihydro- 7 -methoxy-2S, 3 R -dimethyl-2-[4,8-dimethyl-3(E),7-nonadien-6-onyl]-furo-[3,2-C]coumarin Rt AOSO... 

C9H6O2, Mr 146.15, pi.33kPa 153.9 °C, df 0.935, occurs widely in nature and determines, for example, the odor of woodruff. It forms white crystals mp 70.6 °C) with a haylike, spicy odor. When treated with dilute alkali, coumarin is hydrolyzed to the corresponding coumarinic acid salt (cw-2-hydroxycinnamic acid). Heating with concentrated alkali or with sodium ethanolate in ethanol results in the formation of o-coumaric acid salts (trans-2-hydroxycinnamic acid). 3,4-Dihydro-coumarin is obtained by catalytic hydrogenation, for example, with Raney nickel... 

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