Benzo 5-hydroxy

Triazole derivatives have such typical nomenclature as benzo-, hydroxy-, dioxy-, etc... 

In peptide syntheses, where partial racemization of the chiral a-carbon centers is a serious problem, the application of 1-hydroxy-1 H-benzotriazole ( HBT") and DCC has been very successful in increasing yields and decreasing racemization (W. Kdnig, 1970 G.C. Windridge, 1971 H.R. Bosshard, 1973), l-(Acyloxy)-lif-benzotriazoles or l-acyl-17f-benzo-triazole 3-oxides are formed as reactive intermediates. If carboxylic or phosphoric esters are to be formed from the acids and alcohols using DCC, 4-(pyrrolidin-l -yl)pyridine ( PPY A. Hassner, 1978 K.M. Patel, 1979) and HBT are efficient catalysts even with tert-alkyl, choles-teryl, aryl, and other unreactive alcohols as well as with highly bulky or labile acids. 

To a stirred ice-cold solution of ethyl 3,6-dihydro-5-hydroxy-8-methyl-6-(phenylsulfonyl)benzo[l,2-b 4,3-b ]dipyrrole-l-carboxylate (368 mg, 0.85 mmol) in TEA (3ml) was added EtjSiH (1.5 ml), After 15 min the solution was allowed to come to room temperature and stirred for an additional 2h. The solution was evaporated in vacuo and the residue dissolved in CH2CI2 (10 ml), washed.with aq. NaHCOj and dried over MgS04. The solution was mixed with AcjO (1ml) and CH2C12 (1ml) and kept at room temperature for 2 h. The reaction mixture was evaporated and the residue purified by chromatography on silica gel using CHjClj-EtOAc (3 1) for elution. The product (271 mg) was obtained in 71 % yield. 

Table 11 summarizes the main results on the tautomerism of mono-hydroxy-, -mercapto-, -amino- and -methyl-azines and their benzo derivatives, in water. At first sight the equilibrium between 2-hydroxypyridine (71) and pyridin-2-one (72) is one between a benzenoid and a non-benzenoid molecule respectively (71a 72a). However, the pyridinone evidently... 

Benzo[6]furan, cis-5-acetyl-2,3-dihydro-3-hydroxy-2-isopropyl-... 

Benzo[6]furan, 5-acetyl-6-hydroxy-2-isopropenyl-UV, 4, 589 (71AJ093)... 

Benzo[b]furan, cis-2,3-dihydro-3-hydroxy-2-methyl-7-trimethylammonio- H NMR, 4, 571 <71JOC1805>... 

Benzo[c]furan-4,7-dione, l-(2-hydroxy-6-methoxyphenyl)-5-methyl-X-ray, 4, 540 <80JCS(P1)2447> Benzo[c]furan-l(3H)-one, 5-methyl-4,7-dimethoxy-... 

H-Benzo[a]carbazole, 4,4a,5,l 1,1 la,l Ib-hexahydro-synthesis, 4, 283 Benzo[b]carbazole, N-acetyl-photochemical rearrangements, 4, 204 Benzo[/]chroman-4-one, 9-hydroxy-2,2-dimethyl-synthesis, 3, 851 Benzochromanones synthesis, 3, 850, 851, 855 Benzochromones synthesis, 3, 821 Benzocinnoline-N-imide ring expansion, 7, 255 Benzocinnolines synthesis, 2, 69, 75 UV, 2, 127 Benzocoumarins synthesis, 3, 810 Benzo[15]crown-5 potassium complex crystal stmcture, 7, 735 sodium complex crystal stmcture, 7, 735 Benzo[ 18]cr own-6 membrane transport and, 7, 756 Benzo[b]cyclohepta[d]furans synthesis, 4, 106 Benzocycloheptathi azoles synthesis, 5, 120... 

Benzo[b]furan, 2,3-dihydro-2-phenyl-synthesis, 4, 697 Benzo[b]furan, 2,3-dihydroxy-tautomerism, 4, 37 Benzo[6]furan, 4,6-dimethoxy-acylation, 4, 606 Benzo[6]furan, 2,3-dimethyl-acetylation, 4, 606 bromination, 4, 605 photooxygenation, 4, 642 Benzo[b]furan, 5,6-dimethyl-2,3-diphenyl-applications, 4, 709 Benzo[b]furan, 1,3-diphenyl-vertical ionization potential, 4, 587 Benzo[b]furan, 2-ethoxy-5-hydroxy-synthesis, 4, 127... 

Benzo[b]furan, 3-(2-hydroxy-3,5-dichlorophenyl)-5,7-dichloro-properties, 4, 708 Benzo[b]furan, 2-lithio-synthesis, 4, 652 Benzo[i]furan, 3-lithio-ring opening, 4, 79 Benzo[b]furan, methoxy-mass spectrometry, 4, 583 Benzo[b]furan, 6-methoxy-2,3-diphenyl-synthesis, 4, 679... 

Benzo[b]furan-2-carboxylic acid, 6,6 -[(2-hydroxy-l,3-propanediyl)bis(oxy)]bis(3-hydroxy-diethyl ester trisodium salt trihydrate applications, 4, 709... 

C- F coupling constants, 4, 569 Benzo[b]furan-5-carboxylic acid, 4-hydroxy-2-isopropyl-synthesis, 3, 698... 

Ben2o[fa]selenophene, 2-hydroxy-tautomerism, 4, 945 Benzo[h]selenophene, 3-hydroxy-tautomerism, 4, 37, 945 Benzo[h]selenophene, 4-hydroxy-synthesis, 4, 969... 

Benzo[h]selenophene, 7-hydroxy-synthesis, 4, 969 Benzo[h]selenophene, 3-lithio-synthesis, 4, 955 Benzo[h]selenophene, 2-methyl-mass spectra, 4, 942 synthesis, 4, 961 Benzo[h]selenophene, 3-methyl-mass spectra, 4, 942 synthesis, 4, 956... 

Benzo[6]thiophene, 2-acetyl-3-hydroxy-synthesis, 4, 892 Benzo[6]thiophene, 2-acyl-synthesis, 4, 918 Benzo[6]thiophene, 3-acyl-synthesis, 4, 918- 19 Benzo[6]thiophene, acylamino-synthesis, 4, 815 Benzo[6]thiophene, alkenyl-synthesis, 4, 917 Benzo[6]thiophene, 2-alkoxy-synthesis, 4, 929 Benzo[6]thiophene, 3-alkoxy-synthesis, 4, 929 Benzo[6]thiophene, 4-alkoxy-synthesis, 4, 930 Benzo[6]thiophene, 2-alkyl-synthesis, 4, 877-878 Benzo[6]thiophene, 2-alkylthio-synthesis, 4, 931 Benzo[6]thiophene, 2-amino-diazotization, 4, 810 reactivity, 4, 797 stability, 4, 810 synthesis, 4, 869, 924-925 tautomerism, 4, 38 Benzo[6]thiophene, 3-amino-cycloaddition reactions, 4, 68 synthesis, 4, 109, 881, 925 Benzo[6]thiophene, 4-amino-synthesis, 4, 925 Benzo[6]thiophene, 5-amino-synthesis, 4, 925 Benzo[6]thiophene, 7-amino-synthesis, 4, 925 Benzo[6]thiophene, 3-t-amyl-synthesis, 4, 915 Benzo[6]thiophene, 2-aryl-synthesis, 4, 881... 

Cinnolin-4(lH)-one, 8-hydroxy-iodination, 3, 21 Cinnolin-4-ones synthesis, 3, 56 Circular dichroism indolizidines, 4, 450 pyridines and benzo derivatives, 2, 126... 

Propionaldehyde, 3-(7 -benzo[fe]thiophenyl)-synthesis, 4, 906 Propionaldehyde, 3-hydroxy-... 

Some other inhibitors from the patent literature include hydroquinone [129], ionoP [130], and quinone [131]. Other inhibitors used to stabilize MMA include butylated hydroxy toluene (BHT), phenothiazine, methylene blue, hydroxy-diphenylamine and di-/jc/<3-napthol [132]. Several good reviews of inhibition and inhibitors have been written [133-136]. The mechanisms of inhibition are subtle and complicated. For example, it has been reported that highly purified benzo-quinone acts as a retarder rather than an inhibitor [137]. It has been proposed... 

Hydroxy-l,l-dioxo-l,2-dihydro-lX -benzo [e] [1,2] thiazine-3-carboxylic acid isopropyl ester (55)... 

Ratio of Zwittbrion Form to Hydroxy Form (pXr) fob Pyridines and Azines in Which a Benzo Ring Carries a Hydroxyl Group... 

In comparison with mercapto-, hydroxy-, and amino-pyridines, methylpyridines should show an even greater tendency to exist in the methyl form [instead of as pyridmethines (297)] than do the amino compounds to exist as such. If the methyl carbon atom carries an electron-withdrawing group, it might be expected that structures of type 297 would be stabilized. Fused benzo groups should also tend to stabilize the methine form, and tautomerism involving 298 has, in-... 

A tautomeric equilibrium of 4-hydroxy-benzo[c]furan-3(l//)-ones of type 199 has been reported [R, R = Me, (CH2)4, (CH2)5] (89KGS24). 

Very little is known concerning the simple, monocyclic 3-hydroxy-furans (cf. reference 15). Both the oxo and hydroxy forms of the substituted 3-hydroxyfurans 26 and 27 (R = H, CcHn) have been isolated/ but the individual tautomers slowly undergo interconversion. The enol forms give a positive reaction with ferric chloride, react rapidly with bromine, and form a peroxide with oxygen. From chemical evidence, the benzo derivatives of 3-hydroxyfuran, 28 and 29, appear to exist predominantly in the oxo form, and this is further supported by ultraviolet spectral data. Stefanye and Howard- ... 

Chemical Name 4-Hydroxy-a-(4-hydroxy-2-oxo-2H-1-benzopyran-3-yl)-2-oxo-2H-1-benzo-pyran-3-acetic acid ethyl ester... 

Chemical Name 4-Hydroxy-3-(5-methyl-3-isoxazolocarbamyl)-2-methyl-2H-1,2-benzo-thiazine 1,1 -dioxide... 

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