Acetyl-6-methoxybenzaldehyde

The hypothesis of Gray and Bonner (31, 32) that 3-acetyl-6-methoxybenzaldehyde, which is found in the leaves of Encelia farinosa and in the soil beneath these plants, is responsible for the suppression of other plant species has not been substantiated by Muller (33, 34). The same is true for the presumed role of trans-cinnamic acid in "soil sickness associated with guayule (Parthenium argentatum), for the amygdalin of peach roots, and for the phlorizin of apple roots or its breakdown products (35), which were thought to be associated with the "soil sickness" of orchards. 

AlUcin 1. 3-Acetyl-6-methoxybenzaldehyde 1. Ethylene 1. Decomposition products of amyadalln (e.g. HCN)... 

Another interesting case of phytotoxicity, mentioned by Bonner (1950), is that of Encelia farinosa, a desert shrub. This plant, unlike most desert shrubs, does not harbor a growth of annuals under its branches. Investigations gave no indication of excretion of toxins from the roots but when leaves were added to soil, pepper, tomato and com plants were severly injured or killed barley, oats and sunflower were little affected. The toxic substance was shown to have the structure 3-acetyl-6-methoxybenzaldehyde. When leaves of the plant fall on the ground they retain their toxicity for a year or more even though much of the phytotoxin is leached into the soil. 

In the Mojave desert of California, the well-known plant physiologist Fritz Went observed that the soil was usually bare around the shrub Encelia farinosa (Asteraceae) (Went, 1970). He suggested that this situation was produced by the toxic effects of the root exudates. Exudates of the plant are apparently not self-inhibitory, but they inhibit growth of most annual plants. An active substance was later identified as 3-acetyl-6-methoxybenzaldehyde (82) (Fig. 8.22). Although primarily produced in the leaves, this toxin is released when the leaves fall to the ground and decompose. It is persistent and is not removed, except by very heavy rains (Muller, 1953 Harbome, 1982). 

Isochorismis acid is probably the precursor of L-3-carboxyphenylalanine and its derivatives shown in Fig. 147. L-3-Hydroxymethylphenylalanine and l-4-hydroxy-3-hydroxymethylphenylalanine are poisonous to animals by inhibition of L-phenylalanine uptake. They are of significance as feeding deterrents (E 5.5.3). L-3-Carboxyphenylalanine may be an intermediate in the biosynthesis of 3-acetyl-6-methoxybenzaldehyde, a compound involved in the allelopathic interactions between higher plants (E 5.3). 

Acetylmethionine nitrile [538-14-7] M 172.3, m 44-46°- Crystd from diethyl ether. 5-Acetyl-2-methoxybenzaldehyde [531-99-7] M 166.2, m 144°. Crystd from EtOH or Et20. 

Anhalonine and Lophophorine. Spath and Gangl showed that each of these alkaloids contains a methylenedioxy group and that the quarternary iodide prepared from dZ-anhalonine is identical with lophophorine methiodide so that lophophorine must be N-methylanhalonine. Anhalonine was synthesised from 3 4-methylenedioxy-5-methoxybenzaldehyde by condensation with nitromethane, reduction of the product to the corresponding -ethylamine, the acetyl derivative (VII) of which, on treatment with phosphoric anhydride, condensed to 6-methoxy-7 8-methylenedioxy-l-methyl-3 4-dihydrofsoquinoline, m.p. 60-2°. This, on reduction, furnished the corresponding tetrahydrofsoquinoline, which proved to be anhalonine (VIII), and on conversion to the quaternary methiodide the latter was found to be lophophorine (IX) methiodide. The possible alternative, 8-methoxy-6 7-methylenedioxy-l 2-dimethyl-l 2 3 4-tetrahydrofsoquinoline, was prepared by Freund s method and the methiodide shown not to be identical with lophophorine methiodide. 

Acetyl-2-methoxybenzaldehyde [531-99-7] M 166.2, m 144°. Crystd from EtOH or Et20. 

Acetyloxy)-3-methoxybenzaldehyde 2-(Acetyloxy)-1-phenylethanone 1-(Acetyloxy)-2-propanone (Acetyloxy)tributylstannane (Acetyloxy)triphenylstannane 4-Acetyl phenyl acetate... 

The kinetics of acid hydrolysis of the p-methoxybenzaldehyde-O-acyloximes (7) in SDS micelles modified by BuOH has also been fitted to the PIE model [86]. The substrates differ only in their hydrophobicities, and while the acetyl derivative partitions between water and micelles, the octanoyl derivative is wholly micelle-bound. The simple PIE model fits rate data in dilute HCl [Eq. (6)], but it underpredicts observed rate constants in more concentrated acid. This increased rate was analyzed in terms of a model that does not involve a constant value of a but allows concentrations of reactive and inert ions, and Na" ", in the micellar pseudophase to increase, following Langmuir isotherms [106]. This model was reasonably satisfactory except at high 1-butanol concentration. Alternatively, the rate data in more concentrated acid can be fitted in terms of Eq. (12). 

Acetyl-2(6)-methoxybenzaldehyde [531-99-7] M 166.2, m 144 . Extract a solution of the aldehyde in CsHs with 20% aqueous sodium bisulfite, and the bisulfite adduct in the aqueous solution is decomposed by acidifying and heating whereby the aldehyde separates. It is collected, washed with H2O, dried in a vacuurrr. It is recrystallised from EtOH (m 140-141°) and then from Et20 (m 143-144°). [Gray Bormer 7.4w Chem Soc 70 1249 1948, Angyal et al. J Chem Soc 2142 1950, Beilstein 8 IV 1984.]... 

Acetylbenzoic acid Me ester, in A-80015 5-Acetyl-2-methoxybenzaldehyde, in A-80022 Coniferaldehyde, C-80148... 

Preparation by reaction of 3% hydrogen peroxide on 3-acetyl-2-hydroxy-4-methoxybenzaldehyde into solution of 1 N sodium hydroxide (Dakin reaction) (62-65%) [2358,2816]. 

Acetyl-2-hydroxy-3-methoxybenzaldehyde, 1728 5-Acetyl-3-hydroxy-2-methoxybenzaldehyde, 1728 2-(Acetyloxy)-l-(2-hydroxyphenyl)ethanone, 1693 2-(Acetyloxy)-l-(4-hydroxyphenyl)ethanone, 1693 l,l -(4,6-Dihydroxy-l,3-phenylene)bis-ethanone, 1720... 

Methoxyphenyl)-l-(2,4,6-trihydroxyphenyl)ethanone, 1707 [112579-47-2] 5-Acetyl-2-hydroxy-3-methoxybenzaldehyde, 1728... 

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