2-Hydroxy-4,6-dimethoxybenzaldehyd

C9H10O4 2-hydroxy-4,6-dimethoxybenzaldehyde 708-76-9 477.23 41.700 2 16900 C9H11N 2,3-dihydro-1 H-inden-4-amine 32202-61-2 499.21 43.808 2... 

The second synthesis of lasubine II (6) by Narasaka et al. utilizes stereoselective reduction of a /3-hydroxy ketone O-benzyl oxime with lithium aluminum hydride, yielding the corresponding syn-/3-amino alcohol (Scheme 5) 17, 18). The 1,3-dithiane derivative 45 of 3,4-dimethoxybenzaldehyde was converted to 46 in 64% yield via alkylation with 2-bromo-l,l-dimethoxyethane followed by acid hydrolysis. Treatment of the aldol, obtained from condensation of 46 with the kinetic lithium enolate of 5-hexen-2-one, with O-benzylhydroxylamine hy-... 

C9H10O4 3-hydroxy-4,5-dimethoxybenzaldehyde 29865-90-5 20.50 1.1984 2 16943 C9H11N02 3-amino-3-phenylpropionic acid 614-19-7 22.13 1.1160 2... 

The amino group of hydrazides react with aldehydes and ketones. For example, 2-hydrazinocarbonylpyrazine refluxed with acetone-ethanol gave 2-isopropylidene-hydrazinocarbonylpyrazine (51) [which was reduced in methanol over palladium-charcoal to 2-(2 -isopropylhydrazinocarbonyI)pyrazine] (1366,1428,1429). Other references to similar reactions include the following reactions 2-hydrazinocarbonylpyrazine with p-acetamidobenzaldehyde (138) 4-hydroxy-, 4-hydroxy-3-methoxy-and 2-carboxy-3,4-dimethoxybenzaldehydes (1319) furfural (1201) and pyruvic acid (1201) 2-amino-3-hydrazinocarbonylpyrazine with acetone and benzaldehyde (1214) and 2-hydrazinocarbonyl-5,6-dimethyl-3-methylaminopyrazine with acetone (428). 

On standing, the mixture of 2-hydroxy-5-methoxybenzaldehyde, potassium carbonate and dimethyl sulfate as in Example 1 at room temperatures the reaction was completed in 7 days. This was confirmed by gas chromatography. By treating the reaction mixture as described in Example 1, 44.5 g of 2,5-dimethoxybenzaldehyde having a melting point of 47° C were obtained (yield 81.5%). 

Hydroxy-3,5-dimethoxy-benzeneacetic acid, methyl ester (methyl homosyringate) 4-Hydroxy-3,5-dimethoxy-benzoic acid (syringic acid) 4-Hydroxy-3,5-dimethoxy-benzoic acid ethyl ester (ethyl syringate) 4-Hydroxy-3,5-dimethoxy-benzoic acid methyl ester (methyl syringate) 4-Hydroxy-3,5-dimethoxybenzaldehyde (syringaldehyde) 4-Hydroxy-3-methoxy-benzeneacetic acid methyl ester (methyl homovanillate) 4-Hydroxy-3-methoxy-benzoic acid (vanillic acid)... 

The Darzens condensation of aldehydes with a-halo lactones has been investigated as a method for a homologation of the type ArCHO ArCHiCCXIHaCOMe. Addition of an equimolar mixture of 3,5-dimethoxybenzaldehyde and a-bromo-y-valerolactone (mixture of cis and trans isomers) to a solution of Bu OK affords the epimeric mixture of lactones (47) in 78% yield with high stereoselectivity (addition to the carbonyl). Saponification followed by irradiation affords the decarboxylated 3-hydroxy ketone (49) in 62% yield, accompanied by the secondary photolysis product (51). Oxidation of (49) with Jones reagent affords the diketone (50), characterized as its copper(II) chelate (Scheme 12). Methodology has... 

The reactivity of nucleophilic sites of phloroglucinol nucleis with aldehydes has been known for a long time. Using formaldehyde a condensation product is formed which precipitates and can be determined gravimetrically [111]. Colorimetric procedures using substituted benzaldehydes are more popular. The most often used substituted benzaldehyde is vanillin (4-hydroxy-3-methoxybenzaldehyde). Protocols based on dimethylaminocinnamaldehyde have gained interest in the last few years, whereas 2,4-dimethoxybenzaldehyde [132]- although more sensitive than vanillin [133] - is not anymore used. 

In a similar way, 2,3-dimethoxybenzaldehyde with HO-protected 6-chlorohexan-1-ol and lithium afforded after acidic treatment 1,2-dimethoxy-3-(7-hydroxy-heptyl)benzene. Demethylation and bromide formation with boron tribromide gave 1,2-dihydroxy-3-(7-bromohepty0benzene which interacted with lithium-1-octyne in tetrahydrofuran containing hexamethylphosphoric triamide to give after selective catalytic hydrogenation, (15 1)-urushiol (ref. 138). In a different approach this has been synthesised in moderate yield from 2,3-dimethoxyphenyllithium and 1,7-dibromheptane as shown in the following scheme (ref. 139)... 

Kuwanon H (26), an amorphous powder, [a]o — 536°, had a molecular formula C45H44O11. The UV spectrum was similar to that of kuwanon C (33). The MS of 26 showed fragments at w/z 420 (111) and 205 (119). Treatment of 26 with dimethyl sulfate gave a hexamethyl ether 26 a and octamethyl ether 26 b. The hexamethyl ether was pyro-lyzed to give 2 -hydroxy-3 -y,Y-dimethylallyl-2,4,4 -trimethoxychalcone (=morachalcone A trimethyl ether, 120 a), a sample of which was synthesized by reaction of 2 -hydroxy-3 -y,Y-dimethylallyl-4 -methoxyace-tophenone with 2,4-dimethoxybenzaldehyde. The C-NMR spectrum is listed in Table 3. From the spectral data, the difference between kuwanons G (25) and H (26) is the presence of a prenyl group at the C-24 position of 26. 

Preparation from 4-hydroxy-3-methoxybai-zyl methyl ether (SM) in two steps first, direct lithiation of SM with n-butyl lithium in tetrahydrofuran at r.t., followed by quenching with 2,3-dimethoxybenzaldehyde. Then, oxidation of the 8-(2,3-dimetho xyphenyl)-2,7-di-methoxybicyclo[4.2.0] octa-l,3,5-triene-3,8-diol formed (good yield) [1171]. 

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