O-vanillin

Pyrogallol monomethyl ether has been prepared by the methylation of pyrogallol with dimethyl sulfate or methyl iodide by the decarboxylation of 2,3-dihj droxy-4-methoxy-benzoic acid and by the methylation of pyrogallol carbonate with diazomethane and subsequent hydrolysis. The method described is taken from the improved procedure of Baker and Savage for the preparation of pyrogallol monomethyl ether from o-vanillin by oxidation with hydrogen peroxide. 

Ein Dimethoxyazulen [5], wahrscheinlich 4,5-Dimethoxy-azulen, wurde analog von W.Treibs und A. Stein (145) aus o-Vanillin liber das... 

RuX3(EPh3)(tSB) (X=C1, Br E=P, As tSB=tridentate Schiff base made from anti-pyrine and salicylaldehyde, o-vanillin, o-phenylenediamine) are made from the... 

Effects of other additives such as o-vanilline [411], Triton X-10, sodium methylene bis (naphthalene sulfonate). 

Keywords Meldrum s acid, o-vanillin, Knoevenagel condensation, 3-carboxy-coumarin... 

Vanillic acid, hi32 Vanillin, hi 31 o-Vanillin, hi 30 Vanillyl alcohol, hi 35 Veratraldehyde, d430 Veratric acid, d434 Veratrole, d431 Veronal, d280 Vinylacetic acid, b403 Vinyl bromide, b284... 

A general methodology for the construction of quaternary carbon atoms at the carbonyl carbon of ketones has been successfully exploited for the facile synthesis of ( )-lycoramine (299) (Scheme 30) (165). Thus, the O-allylated o-vanillin 322 was allowed to react with vinyl magnesium bromide followed by Jones oxidation, and the acid-catalyzed addition of benzyl IV-methylcarbamate to the intermediate a,(3-unsaturated ketone furnished 323. Wadsworth-Emmons olefination of 323 with the anion derived from diethyl[(benzylideneami-no)methyl]phosphonate (BAMP) provided the 2-azadiene 324. The subsequent regioselective addition of n-butyllithium to 324 delivered a metalloenamine that suffered alkylation with 2-(2-bromoethyl)-2-methyl-l,3-dioxolane to give, after acid-catalyzed hydrolysis of the imine and ketal moieties, the 8-keto aldehyde 325. Base-catalyzed cycloaldolization and dehydration of 325 then provided the 4,4-disubstituted cyclohexenone 326. The entire sequence of reactions involved in the conversion of 323 to 326 proceeded in very good overall yield and in one pot. 

The compound proposed as having the structure of lagerine (55) was synthesized by Hanaoka et al. (45) in a similar way from o-vanillin (167a), pelletierine, and methyl 4-benzyloxy-3-bromohydrocinnamate. In the condensation of pelletierine with 167a in aqueous sodium hydroxide two compounds were formed, a trans-fused quinolizidone (164) and a cw-hemiacetal (165) in the ratio of 1 3. 

ZT-1 is a Schiff base derivative from natural HA, and its chemical name is [51 -(5a,9p,ll )]-5- [(5-chloro-2-hydroxy-3-methoxyphenyl)methylene]amino -ll-ethylidene-5,6,9,10-tetrahydro-7-methyl-5,9-methanocycloocta[b]pyridin-2(lH)-one. ZT-1 is a prodrug and is transformed nonenzymatically into the active compound HA. In aqueous solution, ZT-1 is rapidly degraded into HA and 5-Cl-o-vanillin by hydrolysis. Now, ZT-1 is being developed as a drug candidate for the treatment of AD by Debiopharm S.A. of Switzerland. 

A solution of 1 mole of salicylaldehyde in 1 1. of 1 iV sodium hydroxide is treated at room temperature with 1.2 moles of 3% hydrogen peroxide. The solution darkens and the temperature rises to 45-50°. After 15-20 hrs. the mixture is neutralized with acetic acid and evaporated to dryness at room temperature, and the residue is extracted with toluene. A procedure later applied to o-vanillin specifies that the reaction be run in a stream of nitrogen. ... 

Remko, M. 1979. MO investigations on Ugnin model compounds. Vni. A PCILO study of intramolecular hydrogen bond in guaiacol and o-vanillin. Adv. Mol Relax. Int. Pr. 14(4) 315-320. 

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