3- -benzyl hydroxycoumarin

Reaction of 2-chloromethyl-4//-pyrido[l,2-u]pyrimidine-4-one 162 with various nitronate anions (4 equiv) under phase-transfer conditions with BU4NOH in H2O and CH2CI2 under photo-stimulation gave 2-ethylenic derivatives 164 (01H(55)535). These alkenes 164 were formed by single electron transfer C-alkylation and base-promoted HNO2 elimination from 163. When the ethylenic derivative 164 (R = R ) was unsymmetrical, only the E isomer was isolated. Compound 162 was treated with S-nucleophiles (sodium salt of benzyl mercaptan and benzenesulfinic acid) and the lithium salt of 4-hydroxycoumarin to give compounds 165-167, respectively. 

A variety of other carbon nucleophiles have been alkylated with alcohols including malonate esters, nitroaUcanes, ketonitriles [119, 120], barbituric acid [121], cyanoesters [122], arylacetonitriles [123], 4-hydroxycoumarins [124], oxi-ndoles [125], methylpyrimidines [126], indoles [127], and esters [128]. Selected examples are given in Scheme 35. Thus, benzyl alcohol 15 could be alkylated with nitroethane 147, 1,3-dimethylbarbituric acid 148, phenylacetonitrile 149, methyl-pyrimidine 150, and even f-butyl acetate 151 to give the corresponding alkylated products 152-156. 

The nucleophilic core of 4-hydroxycoumarin (Scheme 18) represents the enolic form of 1,3-dicarbonyl functionality, which was efficiently alkylated with a low amount of Bi(OTf)3 (Schemes 11 and 12). Therefore, Rueping et al. investigated a Bi(OTf)3-catalyzed benzylation of 4-hydroxycoumarins [52],... 

Methyl n-amyl carbinol. 247, 254 Methyl n-amyl ketone, 482 Methylaniline (mono), pure, from commercial methylaniline, 562, 570 P-Methylanthraquinone, 728, 740 Methyl benzoate, 780, 781 p-Methyl benzyl alcohol, 811,812 Methyl benzyl ketone, 727, 735 Methyl y-bromocrotonate, 926, 927 2-Methyl-2-butene, 239 Methyl n-butyl carbinol, 247,255 Methyl n-butyl ether, 314 Methyl n-butyl ketone, 475, 481 4-Methylcarbostyril, 855 p-Methylcinnamic acid, 719 4-Methylcoumarin, 853, 854 Methyl crotonate, 926, 927 Methylethylacetic acid, 354, 358 Methylethylethynyl carbinol, 468 Methyl ethyl ketone, 335, 336 purification of, 172 Methyl n-hexyl ether, 314 Methyl n-hexyl ketone, 335, 336 Methyl n-hexyl ketoxime, 348 Methyl hydrogen adipate, 938 Methyl hydrogen sebacate, 938,939 4-Methyl-7-hydroxycoumarin, 834 Methyl iodide, 287 Methyl isopropyl carbinol, 247,255 Methyl 4-keto-octanoate, 936... 

A PMR study of warfarin (57) and phenprocoumon (58), oral anticoagulants, has revealed that the chemical shift of the benzylic proton can be used to indicate conformational preferences of the substituent in some 3-substituted 4-hydroxycoumarins (78JMC231). 

In the presence of a ruthenium catalyst, 3-diazochroman-2,4-dione 716 undergoes insertion into the O-H bond of alcohols to yield 3-alkyloxy-4-hydroxycoumarins 717 (Equation 285) <2002TL3637>. In the presence of a rhodium catalyst, 3-diazochroman-2,4-dione 716 can undergo insertion into the C-H bond of arenes to yield 3-aryl-4-hydroxy-coumarins (Equation 286) <2005SL927>. In the presence of [Rh(OAc)2]2, 3-diazochroman-2,4-dione 716 can react with acyl or benzyl halides to afford to 3-halo-4-substituted coumarins (Equation 287) <2003T9333> and also with terminal alkynes to give a mixture of 477-furo[3,2-f]chromen-4-ones and 4/7-furo[2,3-3]chromen-4-ones (Equation 288) <2001S735>. 

A third ring was fused to 3-hydroxycoumarin by its reaction with benzyl-ideneacetone to give the ketone (197), which cyclized to the pyranobenzo-pyran (198) under acetylation conditions. Treatment of 3-amino-7-hydroxycoumarin with bromoacetone and cyclization of the product has given psoralen derivatives such as (199). In a new example of the addition... 

In the bicyclic series, the reaction (ref. 46) of umbelliferone (7-hydroxycoumarin) with prenyl bromide (RBr) in dioxan containing silver oxide afforded, osthenol, 7-hydroxy-8 prenylcoumarin (7%), (Table 12.2, ref. 47), 7-hydroxy-6-prenylcoumarin (3%), 7-prenyloxycoumarin (9%) and a prenyl derivative at the benzylic position of the pyrano cyclisation product of osthenol. 

Synonyms/Trade Names 3-(a-Acetonyl)-benzyl-4-hydroxycoumarin 4-Hydroxy-3-(3-oxo-1-phenyl butyl)-2H-1-benzopyran-2-one WARF ... 

Synonyms Bromadialone 3-[3-(4 -Bromobiphenyl-4-yl)-3-hydroxy-1-phenylpropyl]-4-hydroxucoumarin 3-(3-(4 -Bromo(1,1 -biphenyl)-4-yl)-3-hydroxy-1-phenylpropyl)-4-hydroxy-2H-1-benzpyran-2-one Bromone 3-(a-(p-(p-Bromophenyl)-P-hydroxyphenethyl)benzyl)-4-hydroxycoumarin Broprodifacoum Empirical C3oH2sBr04... 

Other possible intermediates are 3-benzyl-4-hydroxycoumarins. Starting from the parent compound (41) the reaction to 3-benzyl-4-chromone (42) is achieved in moderate yield by reduction with diborane, followed by oxidation with sodium bichromate in aqueous sulfuric acid 42). 

Ohnishi, M., Sugawara, R., and Kusano, T. Structure-activity relationship between the hydrophobicity of alkali metal salts of warfarin [3-(acetonyl-benzyl)-4-hydroxycoumarin] and the effectiveness of the taste response to these salts in mice. Biosci. Biotech. Biochem. 1995, 59, 995—1001. 

The seeds contain glucides (coniferin, syrin-gin, benzyl-P-D-glucopyranoside and others), monoterpenoid alcohols, 2-8% (usually 3-7%) volatile oil, about 15% lipids, 20% protein, a (3(1 4) mannan, and flavonoids (quercetin-3-glucuronide, isoquercitrin, etc.), furano- and hydroxycoumarins, among others (jiANGSu marsh wichtl). "... 

A recent pubHcation has described the efficient ruthenium-catalyzed C-3 reductive alkylation of 4-hydroxycoumarin by dehydrogenative oxidation of benzylic alcohols. The optimization of reaction parameters, such as type of catalyst, type of solvent, activation method, reaction time, temperature, and base, was performed (Scheme 48). Under optimized conditions, using [RuCl2(PPh3)3] as catalyst in /erf-amyl alcohol under MW irradiation at 140 °C for 2 h, afforded a satisfying selectivity/conversion. 

Scheme 48 MW-assisted selective C-3 alkylation of 4-hydroxycoumarin with benzyl alcohol. ...

A Study by Xu and coworkers examined a series of cinchona alkaloid derivatives with a benzyl or 1-phenylethyl group at the second nitrogen atom of the squaramide moiety [91]. The catalyst with 1-phenylethyl group and a C6 methoxy group (32) gave the highest yield and enantioselectivity for the conjugate addition of 4-hydroxycoumarins to a-keto esters (Scheme 6.42). 

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