2.4- dimethoxyphenyl 4-methoxyphenyl

Dimethoxyphenyl)(2-methoxyphenyl)methanone, 570 (2,4-Dimethoxyphenyl)(3-methoxyphenyl)methanone, 570 (2,4-Dimethoxyphenyl)(4-methoxyphenyl)methanone, 570 (2,5-Dimethoxyphenyl)(2-methoxyphenyl)methanone, 571 (2,5-Dimethoxyphenyl)(3-methoxyphenyl)methanone, 652 (2,5-Dimethoxyphenyl)(4-methoxyphenyl)methanone, 571 (3,4-Dimethoxyphenyl)(2-methoxyphenyl)methanone, 652 (3,4-Dimethoxyphenyl)(3 -methoxyphenyl)methanone, 640 (3,4-Dimethoxyphenyl)(4-methoxyphenyl)methanone, 572 (2-Hydroxy-6-methoxy-4-methylphenyl)(4-methoxyphenyl)methanone, 622 Phenyl[2,3,4-trihydroxy-5-(l-methylethyl)phenyl]methanone, 637 Phenyl(2,4,6-trimethoxyphenyl)methanone, 569... 

A variant on this structure, dioxyline, has much the same activity as the natural product but shows a better therapeutic ratio. Reduction of the oxime (113) from 3,4-dimethoxyphenyl-acetone (112) affords the veratrylamine homolog bearing a methyl group on the amine carbon atom (114). Acylation of this with 4-ethoxy-3-methoxyphenyl acetyl chloride gives the corresponding amide (115). Cyclization by means of phosphorus oxychloride followed by dehydrogenation over palladium yields dioxyline (116). ... 

Primary 1,2-diamines can be obtained by hydrogenolysis of the benzylic N-auxiliary bond over Pd/C, e.g., the preparation of 249d. The cleavage is not selective in the presence of other benzylic bonds in the molecule, e.g., aryl substituents at Cl - C2. However, in the presence of methoxyphenyl or dimethoxyphenyl C substituents, the N substituents can be selectively removed, as exemplified by the preparation of the primary 1,2-diamine... 

Later, Patterson and Hibbert (S3) stated that ultraviolet absorption of lignin corresponded with the absorptions of hydroxy derivatives of 4-(4,hydroxy-3,methoxyphenyl)-l-propanone and l-(4,hydroxy-3, 5,dimethoxyphenyl)-4-propanone. These authors, therefore, assumed the presence in lignin of a carbonyl group, or of an ethylenic double bond conjugated with an aromatic nucleus. They ascribed the 280 mp band to m-position freedom in the benzene ring and the 310 mp baud to a masked carbonyl group in conjugation with a benzene nucleus. 

It is synthesized by the reaction of 3,4-dimethoxyphenyl-2-amine and l-(4-methoxyphenyl)-3-butanone with a simultaneous reduction of formed imine, giving the product (11.1.30), the methoxyl-protecting groups of which are cleaved by hydrogen bromide, giving dobutamine (11.1.31) [32,33]. 

Peschko and Steglich reported the first biomimetic total synthesis of purpurone (281) starting from 3-(3,4-dimethoxyphenyl)pyruvic acid (1084), 2-(4-methoxyphenyl) ethylamine (1085) and 2, 2, 2 -trichloroethyl-2-bromo-2-(3,4-dimethoxyphenyl)acetate... 

Amide nitrogens can be protected by 4-methoxyphenyl or 2,4-dimethoxyphenyl groups. The protective group can be removed by oxidation with ceric ammonium nitrate.79... 

The following arylacetamides have been prepared from the corresponding nitriles by the same method in the indicated yields 4 -methylphenylacetamide (70%), -isopropylphenylacet-amide (90%), 1-naphthylacetamide (54%), 5,6,7,8-tetrahydro-2-naphthylacetamide (90%), />-methoxyphenyl acetamide (76%), 3,4-dimethoxyphenylacetamide (82%), and 2,3-dimethoxyphenyl-acetamide (91%). Only in the cases of the alkoxy-substituted nitriles are the resulting amides soluble in the reaction mixture the other nitriles do not dissolve completely at any time during the reaction. 

An attempt to utilize this conversion of amines into aldehydes in an isoquinoline synthesis was not successful.439 Instead, reaction between 2-(3,4-dimethoxyphenyl)ethylamine and isatin afforded only the spiro compound 150.439 Reaction between isatin and 2-(3-hydroxy-4-methoxyphenyl)ethylamine gave a mixture of two spiro compounds, while a reaction of isatin, this amine, and benzylamine gave 6-hydroxy-7-methoxy-l-phenyl-1,2,3,4-tetrahydroisoquinoline.439... 

An important extension of this method has made it possible to synthesize polycyclic benzofurans under the influence of various demethylating and dehydrating media.335 For such ring closures, pyridine hydrochloride is especially suitable thus coumestan has been synthesized from 4-hydroxy-3-(2-methoxyphenyl)coumarin.8 4,7-Di hydroxy-3-(2,4-dimethoxyphenyl)coumarin gives coumestol with aniline hydrochloride 336 other polymethoxycoumestans have been obtained with pyridine hydrochloride or with HBr (or HI) and acetic acid.337-339... 

Figure 3.20. Visible spectrum of open form of 2-(2,4-dimethoxyphenyl)-2-(4-methoxyphenyl)-2//-benzo(fe)thieno[3,2- h -1 -benzopyran.

Notes MOP = methoxyphenyl DMOP = dimethoxyphenyl TMOP = trimethoxyphenyl (-) nonphotochromic and (+) photochromic. 

The synthesis of bufotenine itself followed closely upon the proof of its structure. Hoshino and Shimodaira reduced the ethyl ester of 5-ethoxy-indole-3-acetic acid by the Bouveault-Blanc procedure to the corresponding primary alcohol, which was treated with phosphorus tribromide and then dimethylamine, to give the ethyl ether of bufotenine, which was demethylated with aluminum chloride (130). In a later synthesis, 2,5-dimethoxybenzyl cyanide (XXIII) was alkylated by Eisleb s method with dimethylaminoethyl chloride in the presence of sodamide to give l-(2,5-dimethoxyphenyl)-3-dimethylaminopropyl cyanide (XXIV), which was then hydrogenated over Haney nickel to yield 2-(2,5-di-methoxyphenyl)-4-dimethylaminobutylamine (XXV R = Me). De-methylation of this with hydrobromic acid, followed by oxidation of the product (XXV R = H) with potassium ferricyanide yielded bufotenine (XIX) via the related quinone (109). 

Conversion of a 1,2- or 1,3-diol to the p-methoxyphenyl acetal (see below) followed by regioselective reductive cleavage of the acetal using diisobutylalane can be used for the differential protection of a 1,2- or 1,3-dioL. In the example shown in Scheme 4.198, two regioisomeric cleavage products were obtained (8 1) with the major p-methoxybenzyl ether being isolated in 72% yield.144 A related transformation has been applied to 3,4-dimethoxyphenyl acetals.365... 

H p-Hydroxyphenyl (4-hydroxyphenyl) G guaiacyl (4-hydroxy-3-methoxyphenyl) S syringyl (4-hydroxy-3,5-dimethoxyphenyl) C catechol (3,4-dihydroxyphenyl) R SEt ... 

F Berthold, CT Lindgren, ME Lindstrom. Formation of (4-hydroxy-3-methoxyphenyl)-glyoxylic Acid and (4-hydroxy-3,5-dimethoxyphenyl)-glyoxylic Acid during Polysulfide Treatment of Softwood and Hardwood. Holzforschung 52 197-199, 1998. 

T Oki, K Oknbo and H Ishikawa. The oxidative degradation by peracetic acid of 2-(2-methoxyphenoxy)- l-(4-hydroxy-3-methoxyphenyl) ethanol and 2-(2-methoxyphenoxy)-l-(3,4-dimethoxyphenyl) ethnnol. Mokuzai Gakkaishi 18 601-610, 1972. 

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