3-Formyl-4-hydroxy

Ebenfuran I (= 2-(2,4-Dihydroxyphenyl)-5-hydroxy-6-methoxy-benzofuran) (benzofuran) Ebenfuran II (= 2-(2,4-Dihydroxyphenyl)-3-formyl-4-hydroxy-6-methoxy-benzofuran) (benzofuran)... 

Introduction of a formyl group at C3 on methyl ethers can be performed by direct treatment with dichloromethyl methyl ether under titanium tetrachloride catalysis (82CJC2821), as in the conversion of 153 into 154 or by modification of the side chain of pyrone 2, including an oxidation step on methyl ether 156, to afford 157 (87TL1175). 3-Formyl-4-hydroxy-6-methyl-... 

Bei Verwendung von Acrolein im OberschuB entsteht dagegen in einer Cyclisierungsreak-tion das 3 -Formyl-4-hydroxy-tetrahydropyran... 

Analogous to the preparation of coumarins (equation 2), treatment of 2-methy 1-3-formyl-4-hydroxy-quinoline (23) with acetic anhydride and triethylamine affords the pyranoquinoline (24 equation 14). When sodium acetate was employed as the base, instead of triethylamine, no pure (24) could be isolated. 

Schroter HB, Neumann D, Katritzky AR, Swinboume FJ (1966) Withasomnine. A pyrazole alkaloid from Withania somnifera Dun. Tetrahedron 22 2895-2897 Schulte KE, Rucker G, El-Kersch M (1972) Nicotin und 3-Formyl-4-hydroxy-2H-pyran aus... 

Preparation by adding 30% hydrogen peroxide solution to the solution of 3-formyl-4-hydroxy-benzophenone in 10% sodium hydroxide and stirring the mixture at r.t. for 2 h (Dakin oxidation) (42%) [277]. 

An asymmetric synthesis of -formyl -hydroxy esters was also examined by treating the keto aminal 10 a with metal enolates of ethyl acetate. Zinc enolates... 

Einige Formyl-hydroxy- bzw. Alkoxy-formyl-arene, die in jiingerer Zeit nach Gatter-mann-Adams619 synthetisiert wurden, sind in Tab. 19 (S. 96) zusammengestellt. 

Formyl-hydroxy-arene (mit 1,3,5-Triazin/Chlorwasserstoff) allgemeine Herstellungsvorsclirift ... 

Tab. 21 Formyl-hydroxy-arene aus Phenolen durch Duff-Reaktion... 

Formyl-hydroxy-arene durch Dnff-Reaktion in Essigsaure allgememe Versnchsbedingungen 0,1 mol des Hy-... 

Hadacidin (N-formyl hydroxy-aminoacetic acid), which is known to inhibit adenylosuccinate synthetase (7), blocked synthesis of adenosine nucleotides from IMP (Table 1). There was a significant decrease (83%, p <. 001 Student s T test for unpaired values) in newly synthesized ATP and in total adenylates (ZA). The concentration of ATP and the level of the adenylate pool were not decreased. There was a decrease in labelled guanylate in PRBC exposed to hadacidin. 

Hadacidin (N-formyl hydroxy amino acetate)-bound ternary enz)mie-Mn(II)-GTP (or -GDP) complex in the presence of IMP D= 1,000 Presence of IMP increases D significantly (9.35 GHz) (RM)... 

Hydroxy-4-methylthiazole failed to react when submitted to Friedel-Crafts benzoylation conditions (349) on the other hand, it reacted normally in Gattermann and in Reimer-Tiemann formylation reactions, affording the 5-formyl derivative (348). 4-Methylthiazole is insufficiently activated and fails to react under the same conditions. 2,4-Dimethylthiazole undergoes perfluoroalkylation when heated at 200° for 8 hr in a sealed tube with perfluoropropyl iodide and sodium acetate (116) (358). 

Miscellaneous Reactions. The Reimer-Tiemaim reaction of sahcyhc acid (1) with chloroform and alkah (eq. 1) results in the 3- and 5-formyl derivatives. If the reaction is carried out with carbon tetrachloride, the corresponding dicarboxyhc acids form (eq. 2). The products (2) and (3) are 2-hydroxy-l,3-ben2enedicarboxyhc acid [606-19-2] and 4-hydroxy-l,3-ben2enedicarboxyhc acid [636-46-4] respectively. 

The effect of substituents on the reactivity of heterocyclic nuclei is broadly similar to that on benzene. Thus mem-directing groups such as methoxycarbonyl and nitro are deactivating. The effects of strongly activating groups such as amino and hydroxy are difficult to assess since simple amino compounds are unstable and hydroxy compounds exist in an alternative tautomeric form. Comparison of the rates of formylation and trifiuoroacetylation of the parent heterocycle and its 2-methyl derivative indicate the following order of sensitivity to substituent effects furan > tellurophene > selenophene = thiophene... 

Substituted pyrazoles are formylated (Vilsmeier-Haack reaetion) and aeetylated (Friedel-Crafts reaction) at C-4 (B-76MI40402). Both hydroxy and amino substituents in positions 3 and 5 facilitate the reaetion (80ACH(105)127,80CHE1), but the heteroatoms eompete with the C-substitution. For instanee, when the amino derivative (91 R = = Ph, R = H)... 

Using Reimer-Tiemann reaction conditions on 3-alkyl-6-hydroxy-1,2-benzisoxazoles results in formylation occurring at the 7-position (77UC(B)1056). 

Acridine, 9,10-dihydro-9,9-dimethyl-as antidepressant, 1, 169 Acridine, 9-formyl-synthesis, 2, 507 Acridine, 3-hydroxy-formylation, 2, 322 Acridine, 9-hydroxy-N-oxide... 

Imidazole, 4-formyl-5-hydroxy-l-phenyl-mesoionic, 5, 372 Imidazole, 2-formyl-1-methyl-mass spectra, S, 360 Imidazole, 2-formyl-l,4,5-trimethyl-... 

Pyran-2-one, 5,6-dibromo-5,6-dihydro-reactions, 3, 735 Pyran-2-one, 5,6-dihydro-allylic bromination, 3, 799 dehydrogenation, 3, 724, 799 H NMR,3, 581 synthesis, 3, 841, 843 Pyran-2-one, 4,6-dimethyl-irradiation, 3, 677 photochemistry, 3, 678 Pyran-2-one, 5,6-dimethyl-chloromethylation, 3, 680 conformation, 3, 631 Pyran-2-one, 5-f ormyl-IR Spectra, 3, 595 Pyran-2-one, 6-formyl-IR spectra, 3, 595 Pyran-2-one, 5-halo-synthesis, 3, 799 Pyran-2-one, 3-hydroxy-IR spectra, 3, 595 Pyran-2-one, 4-hydroxy-methylation, 2, 57 3, 676 pyran-4-one synthesis from, 3, 816 reactions with phosphorus oxychloride, 2, 57 synthesis, 3, 792, 794, 795, 798 tautomerism, 2, 56 3, 642 Pyran-2-one, 4-hydroxy-6-methyl-methylation, 3, 692 reactions... 

Pyrazole, C-formyl-conformation, 5, 209 Pyrazole, fluoro-reactions, 5, 263, 267 Pyrazole, 4-fluoro-5-hydroxy-tautomerism, 5, 214 Pyrazole, 1-germyl-synthesis, 5, 236 Pyrazole, halo-halogenation by, 5, 54 reactions, 5, 104, 105, 266 reduction, S, 105, 106, 266 Pyrazole, 3-halo-1-phenyl-quaternary salts... 

N-alkylation, 4, 236 Pyrrole, 2-formyl-3,4-diiodo-synthesis, 4, 216 Pyrrole, 2-formyl-1-methyl-conformation, 4, 193 Pyrrole, 2-formyl-5-nitro-conformation, 4, 193 Pyrrole, furyl-rotamers, 4, 546 Pyrrole, 2-(2-furyl)-conformation, 4, 32 Pyrrole, 2-halo-reactions, 4, 78 Pyrrole, 3-halo-reactions, 4, 78 Pyrrole, 2-halomethyl-nucleophilic substitution, 4, 274 reactions, 4, 275 Pyrrole, hydroxy-synthesis, 4, 97 Pyrrole, 1-hydroxy-cycloaddition reactions, 4, 303 deoxygenation, 4, 304 synthesis, 4, 126, 363 tautomerism, 4, 35, 197 Pyrrole, 2-hydroxy-reactions, 4, 76 tautomerism, 4, 36, 198... 

Pyrrole-2-carboxylic acid, 4,5-dimethyl-ethyl ester formylation, 4, 217 Pyrrole-2-carboxylic acid, 3-hydroxy-... 

The preparation of 17j -hydroxy-4a-methyl-5a-androstan-3-one (3) which cannot be obtained by direct alkylation or via formyl or oxalyl ketones was achieved by Schaub in 40% yield by the Stork " alkylation procedure. As discussed in the introduction this method proceeds by trapping the A -enolate (2), obtained from (1) and lithium in liquid ammonia, with methyl iodide. 

Ozonization of A -steroids usually gives complex mixtures (however, see ref. 48). Ozonolysis became a practical step in the general synthesis of B-norsteroids with the discovery that added methanol" (or formaldehyde ) improves yields significantly. Thus, Tanabe and Morisawa prepared 5/ -hydroxy-6/ -formyl-B-norsteroids (74) from cholesterol acetate, dehydroepiandrosterone acetate and pregnenolone acetate in overall yields of 64-74% by the reaction sequence represented below. 

Apparently the role of methanol is to intercept unstable species which otherwise tend to polymerize or rearrange. The methoxy peroxide (72) can be isolated in crystalline form if desired, but it is preferable to treat the methylene dichloride solution at 0° with zinc dust and acetic acid until the mixture shows a negative potassium iodide test. The resulting crude seco-aldehyde (73) is then cyclized to (74) by stirring with neutral alumina in benzene at room temperature for 3 hr. ° Wechter has recently reported a number of transformations of a 5yS-hydroxy-6yS-formyl-B-norpregnane prepared in 8% yield by photolysis and hydrolysis of a 5a-hydroxy-6 -azidopregnane. 

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