Hydroxy urea

Urea hydrogen peroxide Urea hydroperoxide. See Urea peroxide Urea, hydroxy-. See Hydroxyurea Urea/melamine/formaldehyde resin CAS 25036-13-9... 

Supplement (combined with Volume IV) III, 2nd 1929 195-449 Hydroxy-carboxylic acids Carbonic acid, 3. GlycoUic acid, 228. Lactic acid, 261. Tartaric acid, 481. Citric acid, 556. Urea, 42. Cyanamide, 74. Thiocyemic acid, 140. 

Hexamethylolmelamine can further condense in the presence of an acid catalyst ether linkages can also form (see Urea Eormaldehyde ). A wide variety of resins can be obtained by careful selection of pH, reaction temperature, reactant ratio, amino monomer, and extent of condensation. Eiquid coating resins are prepared by reacting methanol or butanol with the initial methylolated products. These can be used to produce hard, solvent-resistant coatings by heating with a variety of hydroxy, carboxyl, and amide functional polymers to produce a cross-linked film. 

A variety of a-amino acid derivatives, including the acids themselves, haUdes, esters, and amides can be transformed iato hydantoias by coadeasatioa with urea (67). a-Hydroxy acids and thek nitriles give a similar reaction (68) ... 

SnCl2 reduction produced the 4-hydrazinoisoxazole (243). In ethanol the diazonium salt reacted with the 4-aminoisoxazole to produce the linear triazine (244) (Scheme 85). Diazoisoxazoles can also be treated with KI or H20/urea to produce the 4-iodo or 4-hydroxy derivatives (63AHC(2)365). These Sandmeyer reactions have been extended to a variety of isoxazole systems (77JMC934, 63AHC(2)365). 

Ketones react with formaldehyde and perchloric acid to produce 2-isoxazolines and also with urea in a-methylnaphthalene at 200 °C (75MIP41600, 75ZOB2090, 79MI41612) with N-hydroxyurea they produce 3-hydroxy-2-carbamoylisoxazolidines or, after acid treatment, 2-isoxazolines are formed (Scheme 123) (75TL2337). 

Common Name 1-(p-toluenesulfonyl)-3-(2-endo-hydroxy-3-endo-D-bornyl)urea... 

The suspension is dissolved by the addition of 20 ml of 1 N caustic soda. The alkaline solution is extracted with ether, acidified with dilute hydrochloric acid and filtered. The precipitate is washed with water and recrystallized from alcohol/water to yield 1-(p-toluene-sulfonyl)-3-(2-endo-hydroxy-3-endo-bornyl)-urea having a melting point of 193° to 195°C. 

A mixture of 24.1 g (0.10 mol) of 3-o-methoxyphenoxy-2-hydroxy-1 -propyl carbamate and 6.0 g (0.10 mol) of urea was heated rapidly to the temperature range of 180°C to 200°C, and maintained there for five hours. The reaction melt was poured into 50% ethyl alcohol, from which the product crystallized as a white solid. The crude yield was 18.3 g (82%) melting point 131.5°C to 137 t. Crystallization from water and 95% alcohol gave 9.0 g (40.3%) of pure 5-o-methoxyphenoxymethyl-2-oxazolidone melting point 141°Cto 143. This melting point was not depressed when the material was mixed with an authentic sample. In additional runs acetone was used Instead of ethyl alcohol with equivalent results. 

The 5-methyl-5-ethyloxazolidine-2,4-dione may be prepared by reacting methyl ethyl ketone with sodium cyanide and with ammonium thiocyanate followed by desulfurization. This intermediate may also be prepared by condensing a-hydroxy-a-methylbutyramide with ethyl chlorocarbonate or by condensing ethyl a-hydroxy-a-methylbutyrate with urea. Another method described (Traube and Aschar, Ber., 46, 2077-1913) consists in the condensation of ethyl a-hydroxy-a-methylbutyrate with guanidine followed by hydrolysis. 

To a cooled solution of 23 parts of sodium in 400 parts of dry ethanol are added 60 parts of dry urea and 132 parts of ethyl o-hydroxy-isobutyrate. The mixture is heated on a steam bath under reflux for about 16 hours and the liberated ammonia is removed from the solution by drawing a current of dry air through it at the boiling point. The solution of the sodium salt of 5,5-dimethyloxazolidine-2,4-dione so obtained is cooled and treated with 284 parts of methyl iodide. The mixture is allowed to stand at room temperature for 3 days, excess methyl iodide and ethanol are then removed by distillation under reduced pressure. 

Use of the valine derived (4S )-3-acetyl-4-isopropyl-1,3-oxazolidine (8)92, the C2-symmetric reagents (2.5,55)-l-acetyl-2,5-bissubstituted pyrrolidine 994, or the doubly deprotonated acetyl urea /V-acetyl- V..V -bis[(.S)-l-phcnylethyl]urea (10), also does not lead to sufficient induced stereoselectivity combined with acceptable chemical yield. When the acetyl urea enolate is reacted with aliphatic and aromatic aldehydes, the diastereomeric adducts (ratios ranging from 1 1 to 3 1) may be separated by column chromatography to give ultimately both enantiomers of the 3-hydroxy acids in 99% ee110. 

Aminotrimethanephosphonic acid is formed from formamide, acetamide, urea, or alkanenitriles with phosphorous acid [296]. By reaction of monoalkyl phosphite or P406 with glacial acetic acid or the corresponding anhydride ethane-1 -hydroxy-1,1-diphosphonic acid is formed after hydrolysis [297,298]. P406 can be obtained from P4 and 02 in a high yield of 85-90% [299]. 

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