Acid Acetic Fused

The reaction of 3-amino-4-cyanofurazan with (3-dicarbonyl compounds in the presence of catalytic amounts of nickel acetylacetonate (Ni(acac)2) gave labile enamines that on treatment with acetic acid afforded fused pyridines of type 100 in 80-95% total yields (Scheme 51) (94MC57). Eurther syntheses of furazano-pyridines can be found in the review by Sheremetev (99RCR137, 99UK154). 

Triazinethiones have been used frequently for the syntheses of triazino-triazines in the literature. Reaction of 6-methyl-5-[substituted styryl]-2/7-[l,2,4]triazine-3-thiones 39 with thiourea or acetylthiourea in dimethylformamide (DMF) led to the formation of N,N -disubstituted thioureas 40. Heating the compound 40b with glacial acetic acid and fused sodium acetate under reflux led to the formation of the compounds 4,7-dimethyl-8-[2-ethenylfuran]-2-thioxo-l,3,5-triazino[5,6- ][l,2,4]triazine 22 (Scheme 6) <2003PS279>. 

Steroidal r,2, 4 -triazolidine-3 -thiones 434 react with chloroacetic acid and fused sodium acetate to give steroidal oxospirothiazolotriazines 435 in good yield (Equation 93) < 1999IJC(B) 1218>. 

Alkyl groups attached to the triazine ring are quite prone to halogena-tion [77CCC2182 84MI7 89H(29)2253 90H(31)1933], A 70% yield of 6-dichloromethyl-5-trichloromethyl-2-phenyl-l, 2,4-triazine was obtained when 5,6-dimethyl-2-phenyl-l,2,4-triazine was heated at 90°C with chlorine dissolved in an acetic acid-acetic anhydride-sodium acetate mixture [90H(31)1933]. Thionyl chloride similarly chlorinated 58 in the fused saturated ring [89H(29)2253] (Scheme 53). 

The pyrazine ring is relatively stable to oxidation, and many pyrazine-carboxylic acids have been prepared from quinoxalines, phenazines, and other fused pyrazines by oxidation with potassium permanganate. This reaction has been most used for the oxidation of quinoxalines, for example, 77 -> 78. The oxidations are usually carried out with potassium permanganate in alkali (397), but may also be effected without added base (398). Crippa and Perroncito (399) have also used chromic oxide in acetic acid-acetic anhydride to oxidize benzo(/]quinoxalines (79). Pyrazines prepared by this method are summarized in Table 11.9 (397-419). 

Aldehyde (2-benzoxazolyl)hydrazones (177 X = O) and (2-benzimidazolyl)hydrazones (177 X = NH) (from aromatic aldehydes and 2-hydrazinobenzoxazole and 2-hydrazinobenzimidazole, respectively) when boiled with glacial acetic acid or fused with air oxidation, undergo ring closure... 

A mixture of benzaldehyde, acetic acid, and fused Na-acetate added to ethyl hydrazinoacetate in water, warmed 15 min. at 50-60°, cooled to 20°, ground K-cyanate added during 15 min., and stirred 2hrs. ethyl l-benzylidene-2-semicarbazidoacetate. Y 87%. F. methods s. S. Smolik and J. Kopecky, Cesk. Farm. 15, 466 (1966) (Czech) C. A. 67, 3036. 

Dissolve 1 0 g. (or 10 ml.) of the amine and 1 0 g. of 2 4-dinitrochloro-benzene in 5-10 ml. of ethanol, add a slight excess of anhydrous potassium carbonate or of powdered fused sodium acetate, reflux the mixture on a water bath for 20-30 minutes, and then pour into water. Wash the precipitated solid with dilute sodium carbonate solution, followed by dilute hydrochloric acid. Recrystallise from ethanol, dilute alcohol or glacial acetic acid. 

Few appHcations for fluoronaphthalenes and related polycycHc stmctures have materialized. The fused-ring bicycHc, suHndac [38194-50-2] a monofluorinated indene-3-acetic acid, is used as an antiinflammatory agent. 

Amino groups are acetylated normally and are converted to hydroxy compounds with nitrous acid. Tlie 2,3-diamino [2,3-f>] derivative gives an imidazolo fused pyridopyrazine with acetic anhydride (75USP3898216). The oxidative removal of hydrazino groups has been used to give ring-unsubstituted derivatives (79JHC305). 

This azlactone is prepared readily from benzaldehyde according to the procedure given for the azlactone of a-ben-zoylamino-/3-(3,4-dimethoxyphenyl)-acrylic acid (Org. Syn. 13, 8). From 53 g. (0.5 mole) of benzaldehyde, 89.5 g. (0.5 mole) of hippuric acid, 41 g. of fused sodium acetate, and 153 g. of acetic anhydride there is obtained 78-80 g. (62-64 per cent yield) of an almost pure product melting at 165-166° (corr.). This material is sufficiently pure for use in the preparation of phenylalanine. By crystallization from 150 cc. of benzene a product melting at 167-168° (corr.) is obtained. 

Benzoic acid [65-85-0] M 122.1, m 122.6-123.1, pK 4.12. For use as a volumetric standard, analytical reagent grade benzoic acid should be carefully fused to ca 130 (to dry it) in a platinum crucible, and then powdered in an agate mortar. Benzoic acid has been crystd from boiling water (charcoal), aq acetic acid, glacial acetic acid, C6H6, aq EtOH, pet ether (b 60-80 ), and from EtOH soln by adding water. It is readily purified by fractional crystn from its melt and by sublimation in a vacuum at 80. ... 

Picric acid [88-89-1] M 229.1, m 122-123 , pK 0.33 (0.37). Crystd first from acetic acid then acetone, toluene, CHCI3, aqueous 30% EtOH, 95% EtOH, MeOH or H2O. Dried in a vacuum oven at 80° for 2h. Alternatively, dried over Mg(C104)2 or fused and allowed to freeze under vacuum three times. Because it is EXPLOSIVE, picric acid should be stored moistened with H2O, and only small portions should be dried at any one time. The dried acid should NOT be heated. 

Trinitrobenzene [99-35-4] M 213.1, m 122-123 . Crystd from glacial acetic acid, CHCI3, CCI4, EtOH aq EtOH or EtOH/ benzene, after (optionally) heating with dil HNO3. Air dried. Fused, and crystd under vacuum. 

The predominant, if not exclusive, formation of 5/7-fused hydroxy ketones was observed in the case of 4-alkylated dienones [(204) (205) (R = CH3) 6 1 from (201) (R = CH3)] ° and of prednisone 21-acetate [(206)-> (207)]. It appears therefore likely that intermediates which represent the conjugate acids of the postulated zwitterionic intermediates in the dienone photoisomerizations [c/. (202), (203)] participate both in the acid-catalyzed transformations of (200) and in the dienone photochemistry in protic solvents. 

Commercial acetic acid is manufactured fiom pyroligneous acid obtained in the destructive distillation of wood. The latter is neutralised with lime, and separated by distillation from wood-spirit and acetone. The crude calcium acetate, which has a dark colour, is then distilled with the requisite quantity of concentrated hydrochloric acid. Anhydrous or glacial acetic acid is obtained by distilling fused sodium acetate with concentrated sulphuric acid. 

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