4-hydroxyphenyl dimethylformamide

A special process for the production of coppered l,5-bis(2-hydroxyphenyl)-formazans 32 is based on the demethylative copperization of 1,5-bis(2-methoxy-phenyl)formazans [63], The method involves heating for a short time in pyridine, formamide, or dimethylformamide. 

Under a nitrogen blanket, a mixture of 3 g of 4-(2-piperidinoethoxy)benzoic acid hydrochloride, 2 drops of dimethylformamide, 2.5 ml of thionyl chloride and 40 ml of chlorobenzene was heated at 70°-75°C for about one hour. The excess thionyl chloride and 15-20 ml of solvent were then distilled off. The remaining suspension was cooled to ambient temperature, and to it were added 100 ml of dichloromethane, 2.7 g of 6-methoxy-2-(4-methoxyphenyl) benzo[b]thiophene and 10 g of aluminum chloride. The solution was stirred for about one hour, 7.5 ml of ethanethiol was added, and the mixture was stirred for 45 minutes more. Then 40 ml of tetrahydrofuran was added, followed by 15 ml of 20% hydrochloric acid, with an exotherm to reflux. Fifty ml of water and 25 ml of saturated aqueous sodium chloride was added. The mixture was stirred and allowed to cool to ambient temperature. The precipitate was collected by filtration and washed successively with 30 ml of water, 40 ml of 25% aqueous tetrahydrofuran, and 35 ml of water. The solids were then dried at 40°C under vacuum to obtain 5.05 g of product, which was identified by NMR as 6-hydroxy-2-(4-hydroxyphenyl)-3-[4-(2-piperidinoethoxy)benzoyl] benzo[b]thiophene hydrochloride melting point 217°C. 

A mixture of l-(4-hydroxyphenyl)-4-(l-methylethyl)piperazine, cis-[2-(2,4-dichloro-phenyl)-2-(lH-l,2,4-triazol-l-ylmethyl)-l,3-dioxolan-4-ylmethyljmethanesulfonate, potassium carbonate and N,N-dimethylformamide is stirred and heated overnight at 120°C. The reaction mixture is cooled and poured onto water. The product is extracted twice with dichloromethane. The combined extracts are washed twice with a potassium carbonate solution, dried, filtered and evaporated. The residue is taken up in methanol and a sodium methanolate solution 30% are added. The whole is stirred and refluxed for 1 h. The mixture is poured onto water and the layers are separated. The organic phase is dried, filtered and evaporated. The cis-l-(4-((2-(2,4-dichlorophenyl)-2-(lH-l,2,4-triazol-l-ylmethyl)-l,3-dioxolan-4-yl)methoxy)phenyl)-4-(l-methylethyl)piperazine was obtained, melting point 116.3°C. 

A mixture of 2-chlorothiazole (5.0 g), ethyl 2-(4-hydroxyphenyl)propionate (8.1 g), potassium carbonate powder (8.65 g) and dimethylformamide (80 ml) is stirred at 150°-155°C for 2.5 hours. The solvent is distilled out under reduced pressure. To the residue is added water and extracted with ether. The extract is washed with a 10% aqueous solution of sodium hydroxide and water and dried. The ether is evaporated. The residue is subjected to chromatography using silica gel and eluted with 50% benzene-hexane, benzene and 10% ether-benzene to yield ethyl 2-[4-(2-thiazolyloxy)-phenyljpropionate (5.8 g). 

Hydroxyphenyl)-telliirophene 0.92 g (11 mmol) of sodium ethanethiolate are dissolved in 9 ml of dimethylformamide (DMF), the solution is stirred under nitrogen, and 0.4 g (1.4 mmol) of 2-(4 -meth-ox) phenyl)-tellurophene in 9 ml of DMF are added. The mixture is heated at 80° for 144 h, cooled, diluted with water, and extracted with diethyl ether. The aqueous phase is acidified with 10% hydrochloric acid, the acidified aqueous phase is extracted with diethyl ether, and the organic extracts are combined, dried with anhydrous sodium sulfate, filtered, and concentrated under vacuum. The residue is chromatographed on silica gel with light petroleum ether (b.p. 40-60°)/diethyl ether (4/1, v/v) as the mobile phase. The product is recrystaUized from ligroin/chloroform (1/1, v/v) yield 0.1 g (26%) m.p. 160 . 

Amino-l,3-dimethyl-5-nitrosouracil stirred ca. 10 min. at 0-2° with equimolar amounts of salicylaldehyde and 80%-hydrazine hydrate in dimethylformamide, then gently refluxed for 3 hrs. l,3-dimethyl-6-o-hydroxyphenyl-7-azalumazine. Y 85%. F. e. s. F. Yoneda et al., J. Heterocyclic Chem. 7, 1443 (1970). 

Monomer and polymer syntheses of PAI were performed as reported previously (9). Diacids with preformed imide groups were reacted with diamines to yield the PAI in one step (9-11). The diphenol 2,2-bis(4-hydroxyphenyl)hexafluoropropane for the PEI synthesis was obtained from Aldrich. The analogous diol with 4 methyl groups ortho to the hydroxy moiety (2,2-bis(3,5-dimethyl-4-hydroxyphenyl)hexafluoropropane) was synthesized by condensing hexafluoroacetone hydrate with 2 moles of 2,6-dimethylphenol following a patent (12). PEFs were obtained from diacids and diols in dry N,N-dimethylformamide (DMF)/pyridine (1/1) and an excess (2.6 mole/mole diacid) of tosyl chloride (13). Reaction time was 3 to 5 h at 120 °C under a dry argon flux. Reduced viscosities (0.5% at 30°C in N-methylpyrrolidone (NMP)) of > 0.35 dUg were required for the preparation of free-standing, non-brittle, methanol stable films. 

Tris(o-hydroxyphenyl)triazine possesses structural features similar to 8-hydroxyquinoline. Linear polymers can be prepared by reaction of this trifunctional ligand with divalent metal salts in solution (32, 34). Reaction in bulk leads to the formation of cross-linked network polymers. Exactly how the difference in polymer structures [31] and [32] was determined was not made clear because both products were insoluble and infusible. It was postulated that the linear structure was obtainable because it precipitated from the reaction solvent before reaction with a third metal ion. Dimethylformamide was used in conjunction with an alcohol, such as methanol or ethanol, for the solution reaction. Temperatures up to 330°C were used for the bulk reaction. 

The preparation of metal chelate polymers from bis(o-hydroxyazo) ligands has been reported. Bis[(o-hydroxyphenyl)azo]- [49] (18-20) and bis(3-hydroxy-4-azopyrazolone) [50] (19,20) compounds are polymerizable. With both classes of ligands, black, intractable products were obtained on reaction with metal salts. Only Cu(II) polymers have been investigated. Dimethylformamide, dioxane, and dioxane-ethanol mixtures were used as solvents. The products were not characterized because of their insolubility. 

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