3,3 ,4,4 -tetramethoxy

Crockett R G M, Campbell A J and Ahmed F R 1990 Structure and molecular-orientation of tetramethoxy-tetraoctoxy phthalocyaninato-polysiloxane Langmuir-Blodgett-films Po/yme/ 31 602-8... 

Thianthrene, 2,3,7,8-tetramethoxy-dication, 3, 968 Thianthrenedicarboxylic acids applications, 3, 993 Thianthrene-2,6-dicarboxylic acids... 

Xanthone, 2-hydroxy-1,3,4,7-tetramethoxy-molecular dimensions, 3, 624 Xanthone, 1,3,7-trihydroxy-synthesis, 3, 837 Xanthone-1-carboxylic acid reactions... 

Concern for the conservation of energy and materials maintains high interest in catalytic and electrochemistry. Oxygen in the presence of metal catalysts is used in CUPROUS ION-CATALYZED OXIDATIVE CLEAVAGE OF AROMATIC o-DIAMINES BY OXYGEN (E,Z)-2,4-HEXADIENEDINITRILE and OXIDATION WITH BIS(SALI-CYLIDENE)ETHYLENEDIIMINOCOBALT(II) (SALCOMINE) 2,6-DI-important industrial method, is accomplished in a convenient lab-scale process in ALDEHYDES FROM OLEFINS CYCLOHEXANE-CARBOXALDEHYDE. An effective and useful electrochemical synthesis is illustrated in the procedure 3,3,6,6-TETRAMETHOXY-1,4-CYCLOHEX ADIENE. ... 

Laudanosine contains four methoxyl groups. By exhaustive methyla-tion it yields trimethylamine and laudanosene (tetramethoxy-o-vinyl-stilbene), CH2=CH—C6H2(OCH3)2—CH=CH—C6H3(OCH3),. On oxidation with manganese dioxide and sulphuric acid it furnishes, in addition to the interesting by-product 2 3 6 7-tetramethoxy-9 10-dihydroanthracene, veratraldehyde and 4 5-dimethoxy-2 )3-methyl-... 

To dehydrolaudanosoline chloride Robinson and Sugasawa, and independently Schopf and Thierfelder ascribe formula (VI), which makes it 2 3 11 12-tetrahydroxy-8-methyldibenzotetrahydropyrrocolinium chloride. The primary tetracetyl-derivative, m.p. 148°, is represented by (VII R = acetyl) and the second acetyl derivative, m.p. 215°, by (VII R = acetyl) with an ethylenic linkage between carbon atoms 15 and 16. Similarly, the initial tetramethoxy-derivative is to be represented by (VI) with the four hydroxyl groups replaced by methoxyl groups the primary product formed on heating, by loss of methyl chloride, will be represented by (VII R = OMe), and the second product, m.p. 201-3°, of the reaction will be represented by (VII R = OMe), with an ethylenic linkage between and C e-... 

Proof of formula (VI) for dehydrolaudanosoline salts was provided by a study of its exhaustive methylation, the products at the first and second stages of the application of this process being 5 6-dimethoxy-2-(3 4 -dimethoxy-6 -vinylphenyl)-l-methyldihydroindole (VIII) and 6-dimethyl-amino-3 4 3 4 -tetramethoxy-6 -vinylstilbene (IX) respectively. 

Nitrogen cannot be eliminated from the latter by further methylation, but (VIII) on catalytic hydrogenation has its vinyl group converted into ethyl and the product, on methylation followed by reduction with sodium amalgam, yields 6-dimethylamino-3 4 3 4 -tetramethoxy-6 -ethyl-a)3-diphenylethane (X), and this, on repetition of the methylation, and reduc-... 

In extension of this work, Sugasawa and Yoshikawa have shown that d/- omolaudanosoline (XIII), on oxidation by chloranil in presence of acetic acid, also gives rise to a dehydro-product, which on methylation furnishes 2 3 11 12-tetramethoxy-8-methyl-6 7 15 16-tetrahydro-5 18 9 14-dibenzopyridocolinium salts (XIV). 

On the basis of these results they assigned formula (II) to ehelerythrine, and this was confirmed by the further observation that dihydrocheler -thrine, m.p. 166-7°, on treatment with phloroglucinol and sulphuric acid and subsequent methylation of the dihydric phenolic base so formed, yields tetramethoxy-A -methyldihydro-a-naphthaphenanthridine (VI), m.p. 182-3°, also obtainable from sanguinarine. ... 

EtOH), is insoluble in benzene or ether, and sparingly in chloroform, but dissolves readily in alkali, the solution darkening in air. The salts are crystalline but unstable. The base forms a crystalline metbiodide and contains two methoxyl and two phenolic hydroxyl groups. On methyla-tion it yields a mixture of corydine and fsocorydine. On exhaustive methylation corytuberine yields eventually trimethylamine and 3 4 5 6-tetramethoxy-8-vinylphenanthrene, m.p. 69°. 

These results the authors consider cannot be aeeounted for on the basis of a 6-membered ring B and the adoption of a 5- or 7-membered ring B introduces a difficulty in explaining the formation of 2 3 4 7-tetramethoxyphenanthraquinone in the oxidation of deaminocolchinol methyl ether. There is, however, a precedent in Weitzenbock s oxidation of 4 5 6 7-dibenzo-d -c /cZoheptatriene-l-aldehyde (X) to phenanthraquinone, for representing the a -unsaturated ketone as 9 12 13 14-tetramethoxy-3 4 5 6-dibenz-d -c /cZoheptatriene-7-one (XI CH2 at —> CO), using the system of numbering adopted by... 

These results indieate that deaminoeolehinol methyl ether is 9 12 13 14-tetramethoxy-3 4 5 6-dibenz-d = -cycloheptatriene (XI j... 

The above described reaction has been extended to the application of the AlMe-BINOL catalyst to reactions of acyclic nitrones. A series chiral AlMe-3,3 -diaryl-BINOL complexes llb-f was investigated as catalysts for the 1,3-dipolar cycloaddition reaction between the cyclic nitrone 14a and ethyl vinyl ether 8a [34], Surprisingly, these catalysts were not sufficiently selective for the reactions of cyclic nitrones with ethyl vinyl ether. Use of the tetramethoxy-substituted derivative llg as the catalyst for the reaction significantly improved the results (Scheme 6.14). In the presence of 10 mol% llg the reaction proceeded in a mixture of CH2CI2 and petroleum ether to give the product 15a in 79% isolated yield. The diastereoselectiv-ity was the same as in the acyclic case giving an excellent ratio of exo-15a and endo-15a of >95 <5, and exo-15a was obtained with up to 82% ee. 

On oxidation with permanganate of potassium, this phenol ether yields tetramethoxy benzoic acid, C H(OCH3)4COOH, melting at 87°. 

A mixture of 38.6 g (0.1 mol) of 3,4,3, 4 -tetramethoxy-6-(a-acetopropyl)-benzophenone, 5.5 g (0.11 mol) of 100% hydrazine hydrate or 3.52 g (0.11 mol) of hydrazine, and 500 ml of absolute ethanol is boiled for 5 hours. After adding 100 ml of benzene, 400 ml of solvent mixture Is distilled off from the reaction mixture by slow boiling for 3 hours. After cooling for 8 hours, 19 g of 5H-2,3-benzodiazepine derivative are separated from the residue as small, white crystals. The melting point is 133°C to 1 36°C (after recrystallizing from absolute ethanol, 136°C). 

Eine fur das Laboratorium angepaBte Variante ermoglicht die Herstellung in siedendem Tetrahydrofuran Natriumboranat wird bei der Reaktion abgeschieden, Natrium-tetramethoxy-borat bleibt in Losung9 ... 

Dichloro-5,8-dimethoxyquinoxalme reacted abnormally with thiourea to give a separable mixture of bis(3-chloro-5,8-dimethoxyquinoxalin-2-yl) sulfide (164) and 1,4,8,ll-tetramethoxy-[l,4]dithiino[2,3- 5,6- ]diquinoxaline (165) [H2NCSNH2 (1 equiv), Et N, Me2NCHO, reflux, 5 h 23% and 52%, respect vely]. analogs likewise " ... 

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