P- Methoxybenzaldehyde

CH3Q—CH — p-Methoxybenzaldehyde Ketones yield secondaiy alcohols ... 

To a hot solution of 20.6 g of sodium in 400 ml of absolute ethanol, there is added a solution of 110 g of phthalide and 110 g of p-methoxybenzaldehyde. A vigorous reaction ensues and one-helf of the alcohol is distilled off over a two hour period. Ice and water are added to the red solution end the diluted solution is ecidified with hydrochloric acid. The resulting gum solidifies end the aqueous phase is removed by decantation. The crude solid is recrystallized twice from two liters of ethenol yielding 2-(p-methoxyphenyl)-1,3-indandione as pale yellow crystals, MP155°-156°C. 

The adduct derived from (a-benzyloxyacetaldehyde (97 % ee) is an important intermediate en route to compactin and mevinolin [76]. In contrast, modest enantioselectivity was attained when the cycloadditions were catalyzed by a chiral BINOL-ytterbium-derived catalyst [77]. Pyridines were used as additives, and the best enantioselection (93% ee) was attained only in the case of p-methoxybenzaldehyde using 2,6-lutidine. 

Methoxybenzaldehyde, 54, 42 p-Methoxybenzaldehyde, by reduction of p-methoxybenzo-nitrile with Raney nickel alloy, 51, 22... 

Methidathion oxon, see Methldathion Methiocarb sulfone, see Methlocarb Methiocarb sulfoxide, see Methiocarb Methionine, see Thiram Methoxyacetaldehyde, see Alachlor Methoxyacetic acid, see 1,4-Dioxane p-Methoxybenzaldehyde, see Methoxychlor p-Methoxybenzoic acid, see Methoxychlor... 

Reduction ofp-methoxybenzaldehyde, typical procedure method A To lithium phenyltel-lurolate prepared from PhLi (2.1 M, 4 8 mL, 10 mmol) and Te (1.27 g, 10 mmol) in THF (30 mL) under Nj is added p-methoxybenzaldehyde (0.272 g, 2 mmol) at -78°C followed by TFA (0.77 mL, 10 mmol). The solution is stirred for a further 2 h, and allowed to warm at room temperature. H O (200 mL) is added and the product is extracted with ether. The extract is dried (Na2S04), evaporated and the residue separated by SiOj chromatography from the formed diphenyl ditellnride, giving p-methoxybenzyl alcohol (0.23 g (93%)). 

Anisindione Anisindione, 3-(/7-methoxyphenyl)indan-l,3-dion (24.2.11), differs from phenidione only in the presence of a p-methoxy group in the phenyl ring, and it is synthesized in the same manner as phenindione, but by using p-methoxybenzaldehyde or p-methoxyphenylacetic acid [30-32]. 

The benzenesulfonyl substituent has also been used in conjunction with the lithiation of an azaindole derivative (86FRP2574406 89FRP26274931), and thus 1-benzenesulfonyl-1//-pyrrolo[3,2-c ]pyridine was able to be successfully lithiated and alkylated with p-methoxybenzaldehyde, although reaction with more hindered ketones could not be achieved (Scheme 19)[91JCS(P1)3I73]. 

Removal of the p-methoxybenzyl group is accomplished by treatment with dichloro-dicyanoquinone (DDQ), which forms quantitatively aminal 17 in an 11.5 1 diastereomeric ratio (Yu and Levy, 1984). The solution is treated with sodium methoxide in methanol, which decomposes the aminal into the desired amine 18 and p-methoxybenzaldehyde. Due to the difficulties in separating the p-methoxybenzaldehyde from amino alcohol 18, the aldehyde is reduced in situ with sodium borohydride. The amino alcohol 18 is crystallized from the reaction mixture after neutralization with acetic acid. Additional recrystallization provides the desired amino alcohol 18 in 94% yield. 

Aryl alkyl amines gave hydroxylamine 0-arylsulfonates when reacted with arylsul-fonyl peroxide. The products were later decomposed to azomethine and further hydrolysis results in the corresponding amine with one less carbon atom. Thus when p-methoxy-benzylamine was treated with p-nitrophenylsulfonyl peroxide at —78 °C in ethyl acetate, p-methoxybenzaldehyde and p-methoxyaniline were obtained . Cyclic amines with p-nitrophenylsulfonyl peroxide were converted to the Al-(p-nitrophenylsulfonyloxy)amine derivatives, which further rearranged to ring-expanded cyclic imines in good yields (equation 9 f. ... 

The use of hydroxy oxazolines 26 in catalytic aryl transfer reactions was investigated subsequently (specifically, addition of BPhs to p-methoxybenzaldehyde in the presence of dimethyl poly(ethylene glycol) (DiMPEG) for details of this... 

Problem 15.14 Synthesize (a) p-methoxybenzaldehyde from benzene (b) cyclohexylethanal by hydrobora-tion and oxidation (c) phenylacetaldehyde, using 1,3-dithiane (d) phenyl n-propyl ketone from a dithiane (e) cyclohexyl phenyl ketone from PhCOOH and RLi (/) 2-heptanone, using a cuprate ... 

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