Phenylglyoxal hydrate

Polyquinoxalines are prepared by the solution polymerization of aromatic b is (0-diamines) such as 3,3,4,4,-tetraminobiphenyl and aromatic bis(glyoxal hydrates) such as 4,4 -oxybis(phenylglyoxal hydrate) ... 

C8H602 phenylglyoxal hydrate 1075-06-5 530.90 46.861 2 13026 C8H7CI03 3-chloro-4-hydroxy-5-methoxybenzaldehyde 19463-48-0 522.15 46.016 2... 

The aldehyde sets to a stiff gel on standing, probably as the result of polymerization. It may be recovered without appreciable loss by distillation. Phenylglyoxal may be preserved also in the form of the hydrate, which is conveniently prepared by dissolving the yellow liquid in 3.3-4 volumes of hot water and allowing crystallization to take place (Note 8). 

The product (2) on dehydrogenation with manganese dioxide hydrate affords the diazomethyl ketone (5) on treatment with nitrous acid it affords phenylglyoxal (6). 

Section II3). It seems therefore that the compound originally formulated as the 3-methyl compound on the basis of covalent hydration studies is in fact the 2-methyl isomer 23. Only one product has been isolated from the reaction of 3,4-diaminopyridine and phenylglyoxal under a variety of conditions. As the isomer was obtained under weakly acidic conditions it was formulated as the 2-phenyl derivative 25 by analogy with the arguments used for the orientation of pyrido[2,3-h]pyrazines. 

Treatment of the dithioketal 118 with hydrazine hydrate and phenylglyoxal in basic medium afforded the corresponding 4-nitro-6-phenyl-3-methylthiopyiidazine 119, while the double amination of 118 yielded aminal 120 that was again reacted with phenylglyoxal to yield the corresponding 3-amino-4-nitropyridazine 121 (2006COR277 Scheme 21). 

Phenylglycol Phenylglycol ether. See Phenoxyethanol Phenylglyoxal 2-diethyf acetal. See 2,2-Diethoxyacetophenone Phenyl hydrate. See Phenol Phenyl hydride. See Benzene Phenyl hydroxide. See Phenol... 

A cetonaphthone, Anthrone Benzalacetone Phenylglyoxal a-Diketone Acetylacetone, Benzoylacetone Quinones, p-Benzoquinone, Anthraquinone Diphenoquinones Ketenes, CH2 = CO, Ph C = CO Monosaccharides T>-Lactose hydrate HCOCOOH Pyruvic acid, Levulinic acid Acetals (NHJ COs... 

Benzoylformaldehyde (phenylglyoxal, see A) forms a relatively stable hydrate, particularly in aqueous solution. The hydrate formed from phenylacetalde-hyde (B) is not very stable under the same conditions. Briefly explain. 

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