2.4- Dimethoxy-6- benzoic

The Birch reduction of 3,4,5-trimethoxybenzoic add 17a b (cognate preparation in Expt 7.19) is of interest in that the product is 1,4-dihydro-3,5-dimethoxy-benzoic add (46) thus revealing that in this reduction the 4-methoxy group is removed by hydrogenolysis. The product possesses two methyl vinyl ether residues which are labile under aqueous acidic conditions to yield the saturated diketone, 3,5-diketocyclohexanecarboxylic add (47). 

The synthesis of A -Ddz-protected amino acids is generally achieved with the 2-(3,5-di-methoxyphenyl)prop-2-yl azidoformate (Ddz-Nj) which is obtained from 3,5-dimethoxy-benzoic acid by a multistep procedure. ] Protection is performed either under Schotten— Baumann conditions, or preferentially, by acylation of the amino acid benzyltrimethylam-monium salts in pyridine.b l N -Acylation of the amino acid methyl esters followed by saponification has been reported to produce the desired derivatives in higher overall yields. 

In some situations, the pH of the buffer can be very critical. An example of such a critical pair of components is given in Fig. 1 a mixture of benzoic and 2,3-dimethoxy benzoic acid, analyzed around pH 4.67. A... 

Hofmann degradation of the crystalline mesembrine methiodide afforded a definite desmethylmesembrine but further degradation failed (11). Alkali fusion, degradation by ozone, and selenium dehydrogenation (6) were also without success. Oxidation with potassium permanganate produced 3,4-dimethoxyphenylglyoxylic acid and 3,4-dimethoxy-benzoic acid (7). 

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)... 

Hexachlorocyclotriphosphatriazeneb (also known as phosphonitrilic chloride trimer, PNC) has also been found to promote the polycondensation of carboxylic acids and phenols to yield carboxylic esters in high yields. This process has been successfully applied to the preparation of polyesters directly from p- and m-hydroxy-benzoic acids and also from a combination of dicarboxylic acids and bisphenols (Table 18)13, especially from 4-hydroxy 3,5-dimethoxy benzoic acid (syringic acid) in high yield. 

Pseudaconine is the parent of four ester-alkaloids found in nature two of these, pseudaconitine (54) and a-pseudaconitine (61), are certainly isomeric since on hydrolysis they both yield acetic acid, 3,4-dimethoxy-benzoic acid, and pseudaconine. The physical properties of the two isomeric alkaloids and their salts are very similar (cf. Table 13), and it appears (61) that they may differ only in the position of attachment of the 3,4-dimethoxybenzoyl group since the difference between the 3,4-dimethoxybenzoylpseudaconines (the intermediate hydrolysis products) is much greater than that between the diesters. 

In a regiocontrolled single-step domino process, the (N-cyclohexyllamide of 3,5-dimethoxy-benzoic acid and ethyl vinyl ether react in the presence of (F3CS02)20 (lequiv.) and 2-chloropyridine (1 equiv.) in DCM solution at — 78-> 0°C. After aqueous workup, a product A is obtained in 97% yield. 

Gourmelon and Graff " ° have examined the reaction of 3,5-dimethoxy-benzoic acid 155 with MA. In addition to acylation product 156, a significant amount of the spiro compound 157 was formed. A rigorous structure proof for the products was given. 

Obtained by reaction of 2,3-dimethoxy-benzoic acid with 1,2,3,5-tetramethoxy-benzene in trifluoroacetic anhydride for 23hatr.t. [1185]. m.p. and Spectra (NA) TLC [1185],... 

Preparation by reaction of 2,5-dimethoxy-benzoic acid with l-acetoxy-3,4,5-trimeth-oxybenzene in the presence of trifluoroacetic anhydride for two weeks at r.t., followed by hydrolysis of the reaction mixture (52%) [1186], (45%) [1160]. 

HO" COCH3 ing chlorobenzene (71%) [2395]. The starting material (SM) was prepared by a three-step procedure from 3,5-dimethoxy-benzoic acid. 

Benzoic acid, 2-benzoyl-, methyl ester [606-28-0,21204-864], 63 Benzoic acid, 4-bromo- [586-76-5], 86 Benzoic acid, 4-chloro- [74-11-3], 86 Benzoic acid, 2-[(diethylamino)carbonyl]-, methyl ester [2659344-2], 63 Benzoic acid, 2,4-dimethoxy- [91-52-1 ], 31 Benzoic acid, 3,4-dimethoxy- [93-07-2], 31 Benzoic acid, 3,4-dimethyl- [619-04-5], 31 Benzoic acid, 3,5-dimethyl- [499-06-9], 86 Benzoic acid, 4-hydroxy- [99-96-7], 60 Benzoic acid, 3-methyl- [99-04-7], 86 Benzoic acid, 4-methyl- [99-94-5], 86 Benzoic acid, 2,4,6-tnmethyl- [480-63-7],... 

All cements that contain eugenol inhibit the polymerization of acrylates, and those of EBA-eugenol are no exception. In order to remedy this and other defects, Brauer and his coworkers examined alternatives to eugenol (Figure 9.7). These included the esters of vanillic acid (3-methoxy-4-hydroxybenzoic acid, HV) and syringic acid (3,5-dimethoxy-4-hydroxy-benzoic acid). Both are 3-methoxy-4-hydroxy compounds and are thus chemically related to eugenol and guaiacol. Both are solids and have to be dissolved in EBA where they form satisfactory cements with EBA zinc oxide powder. The vanillate (EBA-HV) cements are the more important. 

Figure 12.12 THM GC/MS curves of a Winsor Newton lemon alkyd paint (a) and of an alkyd sample taken from Fontana s work Concetto spaziale (1961) (b). Peak assignments 1, 1,3 dimethoxy 2 propanol 2, 1,2,3 trimethoxy propane 3, 3 methoxy 1,2 propandiol 4, 4 chloro benzenamine 5, 3 methoxy 2,2 bis(methoxymethyl) 1 propanol 6, 3 chloro N methyl benzenamine 7, 3 methoxy 2 methoxymethyl 1 propanol 8, 4 chloro N methyl benzenamine 9, phthalic anhydride 10, 3 chloro 4 methoxy benzenamine 11, suberic acid dimethyl ester 12, dimethyl phthalate 13, azelaic acid dimethyl ester 14, sebacic acid dimethyl ester 15, palmitic acid methyl ester 16, oleic acid methyl ester 17, stearic acid methyl ester 18, 12 hydroxy stearic acid methyl ester 19, 12 methoxy stearic acid methyl ester 20, styrene 21, 2 (2 methoxyethoxy) ethanol 22, 1,1 oxybis(2 methoxy ethane) 23, benzoic acid methyl ester 24, adipic acid dimethyl ester 25, hexadecenoic acid methyl ester 26, dihydroisopimaric acid methyl ester 27, dehydroabietic acid methyl ester 28, 4 epidehydroabietol...

Convert benzoic acid to 3,5-dihydroxybenzoic acid (alpha-resorcyclic acid) (I). 50 g (I), 134 g dimethylsulfate, 60 g NaOH, 300 ml water add 35 g NaOH and reflux to obtain about 50 g 3,5-dimethoxybenzoic acid (II) which is converted to dimethoxybenzoyl chloride (HI) with PCI5. Extract the (HI) with ether and filter. Saturate the ether with NH3 at 0° C and filter. Wash with ether and water and reciystallize from hot water to get 3,5-dimethoxy-benzamide (IV). To a solution of 1 M of n-hexyl bromide (or 1,2-dimethylheptyl bromide, etc.) add 24.3 g Mg in 200 ml ether to... 

Mono(2,6-dimethoxybenzoyl)tartaric acid Butanedioic acid, 2-[(2,6-dimethoxybenzoyl)oxy-3-hydroxy-, [R-(R, R )]- (12) (116212-44-3) 2,6-Dimethoxybenzoic acid Benzoic acid, 2,6-dimethoxy- (8,9) (1466-76-8) Trifluoroadetic anhydride Acetic acid, tritluoro-, anhydride (8,9) (407-25-0) Borane-Tetrahydrofuran Furan, tetrahydro-, compd. with borane (1 1) (8,9) (14044-65-6)... 

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