Potassium acetate, fused

In a 3-I. round-bottomed flask provided with a mechanical stirrer and a 90-cm. air-cooled condenser are placed 288 g. (3 moles) of freshly distilled furfural, 460 g. (425 cc., 4.5 moles) of acetic anhydride, and 294 g. (3 moles) of dry, pulverized, freshly fused potassium acetate (Note 1). The ingredients are mixed thoroughly, stirring is started, and the flask is heated in an oil bath at 150° (bath temperature) for four hours, without interruption (Note 2). It is well to make provision for acetic acid vapor which escapes through the air condenser. 

The condensation of furo[3,2- ]pyrrole-type aldehydes 8g and 265-267 with hippuric acid was carried out in dry acetic anhydride catalyzed by potassium acetate as is shown in Scheme 26. The product methyl and ethyl 2-[( )-(5-oxo-2-phenyl-l,3-oxazol-5(4//)-ylidene)methyl]furo[3,2- ]pyrrol-5-carboxylates 268a-d were obtained. The course of the reaction was compared with the reaction of 5-arylated furan-2-carbaldehydes with hippuric acid. It was found that the carbonyl group attached at G-2 of the fused system 8 is less reactive than the carbonyl group in 5-arylated furan-2-carbaldehydes in this reaction <2004MOL11>. The configuration of the carbon-carbon double bond was determined using two-dimensional (2-D) NMR spectroscopic measurements and confirmed the (E) configuration of the products. 

In a well-ventilated hood, behind an explosion shield, to a finely divided suspension of 2.6 gm (0.01 mole) of fumardianilide in 90 ml of glacial acetic acid, 30 ml of acetic anhydride, and also containing 8 gm of freshly fused potassium acetate and 2 gm of phosphorus pentoxide, cooled to +7°C is added, slowly, with vigorous stirring, 25 ml of a 20 % solution of nitrosyl chloride (5 gm of nitrosyl chloride, 0.08 mole) in acetic anhydride. After the addition has been completed, stirring is continued for 2 hr while the reaction temperature is maintained between 7° and 12°C. During this period, much of the suspended material dissolves. 

The procedure described here is based on a method outlined in U. S. patent 2,444,536.2 N-Phenylmaleimide has also been prepared by the dry distillation of the aniline salt of malic acid, 4 by treating the aniline salt of malic acid with phosphorus pent-oxide,5 and by treating maleanilic acid with phosphorus trichloride or with phosphorus pentoxide.5 Ring-substituted N-phenylmaleimides, viz., N-(/>-methoxyphenyl)-, N-(p-ethoxy-phenyl)-, and N-(/>-nitrophenyl)maleimide, have been prepared by treatment of the appropriate maleanilic acids with acetic anhydride and fused potassium acetate.7... 

Method II.—200 gms. of pure potassium acetate are fused in a shallow dish, as described on p. 509, except that, unlike sodium acetate, the crystals contain no water of crystallisation, and only melt once. The solidified salt is finely powdered, and while still warm placed in a desiccator. 

Fused potassium acetate should be freshly prepared following the procedure described for sodium acetate (Section 4.2.69, p. 464). It may, however, be replaced by an equivalent quantity of freshly fused sodium acetate, but the reaction is slower and a further 3-4 hours heating is necessary. 

A procedure which dispenses with the isolation of the nitroso derivative has been employed in one instance.8 Addition of a benzene solution of nitrosyl chloride to a benzene solution of acetanilide in the presence of fused potassium acetate at 5°, followed by wanning at 30° for two hours, gave a 40% yield of biphenyl. 

Ethyl 2-Iodophenyl Tellurium5 In 100 ml of pure chloroform containing 100 mg of 18-crown-6 are suspended 15.9 g (0.05 mol) of 2-iodobenzenediazonium tetrafluoroborate and the suspension is cooled to 0°. 23.4 g (0.075 mol) of diethyl ditellurium are added, the mixture is stirred Vigorously, and 10 g (10 mmol) of finely ground, fused potassium acetate are added. The mixture is allowed to warm to 20° and is stirred for 4 h. It is then filtered, the residue is washed with chloroform, the filtrate is washed with water, and the chloroform layer is dried. The chloroform is distilled and the residue is fractionally distilled under vacuum yield 4.5 g (25%) b.p. 12671 torr. 

Benzotellurazole1 14.3 g (50 mmol) of 2-formylphenyl butyl tellurium, 3.8 g (55 mmol) of hydroxyl-amine hydrochloride, and 5.9 g (60 mmol) of fused potassium acetate are added to 100 ml of absolute ethanol and the mixture is heated under reflux with stirring for 2 h. The mixture is then concentrated, extracted with chloroform, and the extract is concentrated. The residue (the crude oxime) is added to a mixture of 50 ml of 85% phosphoric acid and 100 g of phosphorus pentoxide. This mixture is stirred and heated at 100° for 1 h, cooled, and poured into a mixture of ice and aqueous ammonia. The mixture is filtered, the solid is extracted with chloroform and the extract is dried and evaporated. The residue is recrystallized from methanol yield 4.6 g (40%) m.p. 173. ... 

Fused potassium acetate, according to the experiments of Lassar-Cohn,8 yields at the cathode methane, hydrogen, and... 

Starting from 1-methyl-17/-pyrrole-2-carboxylic acid, the tricyclic fused quinolin-4-one and naphthyridin-4-one derivatives 441 were prepared, in only three steps, by an intramolecular Heck cyclization of derivative 440 (Scheme 94) <2005EJ02091>. This reaction was performed in DMA as solvent, with potassium acetate as base and Pd(PPh3)4 as catalyst. The use of microwave irradiation, in some cases, gives better yields of cyclized products. 

A convenient approach to the synthesis of fused furofuran derivatives is provided by the tetrabutylammonium peroxydisulfate-mediated oxidative cycloaddition of 1,3-dicarbonyl compounds to cyclic enol ethers. In the presence of a base such as potassium acetate in acetonitrile, several fused acetal derivatives of type 39 have been prepared in 82-90% yield (Equation 62) <200081091 >. 

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