3.4- Dihydro-8-methoxy-2//-1 -benzopyran

Benzoic acid, 1,1-dimethylethyl ester [Benzoic acid, fe/7-butyl ester] as impurity in /erV-butyllithium, 55, 125 Benzoic acid, 4 methoxy, methyl ester [Anisic acid, methyl ester], 55, 40, 41 3//-2-BENZOPYRAN-3-ONE, 1,4-dihydro-... 

CN 5-[[4-(3,4-dihydro-6-hydroxy-2,5,7,8-tetramethyl-2//-l-benzopyran-2-yl)methoxy]pheny ]methyl-2,4-thiazolidinedione... 

Chantrapromma, K. et al., 5-Hydroxy-7-methoxy-2-phenyl-4H-l-benzopyran-4-one (tectochrysin) and 2,5-dihydroxy-7-methoxy-2-phenyl-2,3-dihydro-4H-l-benzopyran-4-one isolation from Uvaria rufas and X-ray structures, Aust. J. Chem., 42, 2289, 1989. 

One of six chromenone glycosides isolated from the tubers of Eranthis hyemalis and structurally identified by a combination of FAB-MS and 2D (COSY, COLOC) NMR techniques was compound (15), a / -D-glucopyranoside of 7-(hydroxymethyl)-2,3-dihydro-2-(l-hydroxy-l-methylethyl)-4-methoxy-5/7-furo[3,2- ][l]benzopyran-5-one <91HCA611). 

In a TTN-mediated oxidative rearrangement route to certain linear pyranoisoflavones, the aurones (2-alkylidene-6,7-dihydro-4-methoxy-7,7-dimethyl-5//-furo[3,2- ][l]benzopyran-3(277),5-diones) (45 R1 = R2 = H, OMe) were obtained in low yields (Equation (20)) <89BCJ826,92H(34)505>. A signal at d 6.45 ppm in the H NMR spectrum due to the benzylidene proton was noted as being characteristic of the aurone system. 

Photooxygenation of natural visnagin (87) affords a variety of products including 4,9-dihydro-4,9-epidioxo-4-methoxy-7-methylidenylfuro[3,2-g]-benzopyran-5,6-dione and 9-hydroperoxy-4-methoxy-7-methyl-5H-furo[3,2-g]benzopyran-5-one. ° Similar studies have also been reported on the 4-hydroxyl derivative. 

Thionyl chloride is one of the most common and effective reagents to effect cyclodehydration of 2-acylamino ketones. For example, Litak and Kauffman refluxed 446 in SOCI2 and isolated 4-[2-(3,4-dihydro-2//-l-benzopyran-6-yl)oxazol-5-ylpyridine 447 in excellent yield (Scheme 1.123). Both 447 and 441 were starting materials for reactive fluorescent stains to be used in fluorescence microscopy. Reck and Friedrichsen refluxed 448 in SOCl2/chloroform and prepared 4-(methoxy-carbonyl)-2-methyl-5-oxazoleacetic acid methyl ester 449 (Scheme 1.123). This material was a precursor of the novel diene 4-methoxy-2-methyl-furo[3,4-ti]ox-azole-6-carboxylic acid methyl ester 450. 

Boiled chestnut (only) n-Heptane Hexanal 2-Decenal 2-Undecenal n-Tridecane Eicosene 2,5-Dihydro-3-methylfurandione 2-Methoxy-6-methylpyrazine 6,7-Dimethoxy-2H-1 -benzopyran-2-one Mono(2-ethylhexyl) hexanedioate Eicosanoic acid Docos oic acid Heptacosane Cyclotetracosane 1-Docosanol Hexyl acetate 2,3-Dimethylpyrazine 2-Acetylthiazoline ... 

A mixture of 5.67 g 4-(l,2-dihydro-2-oxo-l-pyridyl)-6-methoxy-2,2-dimethyl-2//-l-benzopyran (20 mmol) and 6.93 g pyridine hydrochloride (60 mmol) was heated to melt at 170°C for 2 h. The hot solution was poured into 150 mL 2% H2SO4, and the product was extracted with CH2CI2. The organic layer was dried over MgS04 and evaporated. The... 

Dihydro-5-hydroxy-7-methoxy-2,3-dimethyl-6-(3-methyl-2-butenylV4-oxo-P-phenyl-2 -l-benzopyran-8-propanoic acid, 9CI... 

Dihydro-6-methoxy-2,8-dimethyl-2ir-l-benzopyran-2-yl)methyl)-l,2,3,3a,7,7a-hexahydro-5-(2-hydroxy-2-methylpropyl)-3a,7a-dimethyl-4. 7-inden-4-one, 9CI [148270-16-0]... 

Me ether 3,4-Dihydro-4,6,8 trihydroxy-7 methoxy-3-methyl- IH-2-benzopyran-1-one. Lignicol CjiHiA M 240.212... 

Dihydro-7-methoxy-2,3-dimethyl-2-(4-oxopentyl)-4 -furo[3,2-c][l]benzopyran-4-one, 9CI... 

Dihydro-8- l-hydroxy-l-methylethyl)-5-methoxy-2Y -furo[2,3-h]-l-benzopyran-2-one, 9CI. 

Antiarone C, in P-20032 Antiarone D, in P-20032 Antiarone E, in P-20033 Antiarone G, in T-20056 Antiarone H, in T-20055 3,4-Dihydro-5-hydroxy-7-methoxy-2,3-dimethyl-6-(3-methyl-2-butenyl)-4-oxo-)ff-phenyl-2//-1 -benzopyran-8-propanoic acid, D-30110... 

Bolegrevilol, in T-20106 6-[(3,4-Dihydro-6-methoxy-2,8-dimethyl-2/7-l-benzopyran-2-yl)methyl]-l,2,3,3a,7,7a-hexahydro-5-(2-hydroxy-2-methylpropyl)-3fl,7a-dimethyl-4//-inden-4-one, D-30118 6-[(3,4-Dihydro-6-methoxy-2,8-dimethyl-2//-1 -benzopyran-2-yl)methyl]-l,2,3,3a,7,7fl-hexahydro-5-(2-hydroxy-2-methylpropyl)-3a,7fl-dimethyl-4/7-inden-4-one 2 -Epimer, in D-30118... 

Figure 7. Tenuifodione (24), tenuifone (25), izalpinin (3,5-dihydroxy-7-methoxyflavone, 26), alpinone (27), arborinone (28), irilin B (5,7,2, -tiihydroxy-6-methoxyisflavone, 29), irisone A (7-(2-methoxyphenyl)-9-hydroxy-8H-l,3-dioxolo[4,5-g][l]benzopyran-8-one, 30) irisone B (7-(2-hydroxyphenyl)-9-hydroxy-8H-l,3-dioxol[4,5-g][l]tenzopyran-8-one, 31), betavulgarin (2 -hydroxy-6,7-methylenedioxy-5-methoxyisoflavone, 14) (Figure 5), p-sitosterol (32), 5,7-dihydroxy-2 ,6-dimethoxyisoflavone (33), 2 ,5-dihdroxy-6,7-methylenedioxy flavanone (34), irisoid A (l,8,10-trihydroxy-9-methoxy-5,7-dihydro[2]benzopyrano[4,5-b][l]benzopyran-7-one, 35) and ethyl-P-D-gJueopyranoside (36).

Dihydro- ll-hydroxy-5-methoxy-2,2-dimethyl-2H,8li-benzofuro[3,2-c]pyrano[2,3-f [l]benzopyran-8-one, 9CI [23013-86-7]... 

Dihydroxyphenyl)-2,3-dihydro-5-hydroxy-7-methoxy-6-methyl-4H-l-benzopyran-4-one. 2, 4, 5-Trihydroxy-7-methoxy-6-methylisoflavanone [1236-43-7]... 

De-Me [58210-35-8]. a,oL-Dimethylallylcyclolobin, 4- 3,4-Dihydro- 7-hydroxy-2H-1 -benzopyran- 3-yl)-6-, 1 -dimethyl-2-propenyl)-3-methoxy-1,2-benzenediol, 9CI C21H24O5 M 356.418... 

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