Urea, 1,1-Dimethyl

Oligomers of phosgene, such as diphosgene [503-38-8] (COCl2)2, have found use in the laboratory preparation of isocyanates. Carbamoyl chlorides, A[,A/-disubstituted ureas, dimethyl- and diphenylcarbonates, and arylsulfonyl isocyanates have also been used to convert amines into urea intermediates, which are subsequendy pyroly2ed to yield isocyanates. These methods have found appHcations for preparation of low boiling point aUphatic isocyanates (2,9,17). 

Phenyl urea herbicides (e.g., 3-[3-chlorophenyl]l,1-urea dimethyl-(3,3,4- dichlorophenyl]urea)... 

An alternative synthetic approach to Boc-protected l -aminoferrocene-l-carboxylic acid 40 was recently described by Rapic and co-workers, and is shown in Scheme 12.7. Hydrolysis of carbamate-ester by an equimolar amount of sodium hydroxide in aqueous ethanol gave 90% of tert-butyl l -carboxy-l-ferrocenecarbamate.52 During the synthesis the symmetrical ferrocenyl-substituted urea, dimethyl l, l -ureylenedi(l-ferrocenecarboxylate) 39 was formed as a by-product (Scheme 12.7).53 The ferrocenium molecules were conjugated through a urea linker, which upon deprotection may be used in condensation reactions. 

With the replacement of formaldehyde with such polymerising agents as urea, dimethyl methylene and ether and the introduction of a more complex variety of aromatic base groups, a very wide range of synthetic tanning materials (syntans) have become available commercially. 

Acetonyl urea dimethyl hydantoin (CH3)2 128-13 tri-/al- 175 subl- S- S- S-... 

Dixon, N., Jackson, W., Marty, W. and Sargeson, A. (1982) Base hydrolysis of pentaammineco-balt(ll) complexes of urea, dimethyl sulfoxide and trimethyl phosphate. Inorganic Chemistry 21, 688-697. 

Bromo-2-nitropropane-1,3-diol Diazolidinyl urea Dimethyl oxazolidine Hydroxyethyl-s-triazine 2[(-Hydroxymethyl) amino] ethanol Methylchloroisothiazolinone Sodium o-phenylphenate 2,2 -Thiobis (4-chlorophenol) biocide, nonprotein glues Tris (hydroxymethyl) nitromethane biocide, nonprotein sizes Tris (hydroxymethyl) nitromethane biocide, oil field applies. 

Dimethoxypropane Dimethylol urea Dimethyl phthalate Dimethyl sulfoxide 4,6-Dinitro-o-cresol... 

It has been reported that reaction of tran.s-1,2-diaminocyclohexane 1136a with either phosgene or phosgene equivalents such as l.l -carbonyldiimidazole, urea, dimethyl carbonate, or methyl chloroformate does not give the desired imidazolidin-2-one 1139a, but rather an oligomeric product [806]. This indicates that the in-termolecular reaction competes effectively with the intramolecular cyclization, a result that has some precedent in the reaction of 1,2-diaminoethane (ethylenedi-amine) with urea [807]. 

Denaturation and renaturation of lentinan by urea, dimethyl sulfoxide (DMSO) or sodium hydroxide (NaOH). (a) Lentinan was mixed with urea (solid circle) or DMSO (open circle) for 30 min at room temperature. Renatured lentinan was prepared by removal of urea (solid square) or DMSO (open square) through dialysis against distilled water, (b) Lentinan was denatured with NaOH by mixing at 25° C for 10 min (solid circle). Renatured lentinan was obtained by neutralization, followed by dialysis against distilled water after mixing with NaOH at 0° C for 30 min (open circle), or 25° C for 10 min (open square) [32]. 

Facilitating the introduction of the metal carboxylates into the epoxy compositions is possible by complexing them with such volatile, coordinating, and electron-donating solvents as dimethyl formamide, dimethyl sulfoxide, dimethyl sulfolane, tetramethyl urea, dimethyl acetamide, methylcaprolactam, or methyl pyrrollidone. These solvents evaporate when applied to a surface to reactivate the salt catalysts by the formation of the occupied coordination sites, which results in the reaction of the epoxy oligomers with the carboxylic acid anhydrides [214]. 

Under the same conditions the even more reactive compounds 1,6-dimethylnaphthalene, phenol, and wt-cresol were nitrated very rapidly by an autocatalytic process [nitrous acid being generated in the way already discussed ( 4.3.3)]. However, by adding urea to the solutions the autocatalytic reaction could be suppressed, and 1,6-dimethyl-naphthalene and phenol were found to be nitrated about 700 times faster than benzene. Again, the barrier of the encounter rate of reaction with nitronium ions was broken, and the occurrence of nitration by the special mechanism, via nitrosation, demonstrated. 

Alkylation of bis(4-methyl-2-thiazolyl)urea (257) with dimethyl sulfate gives product 258 dimethylated on the ring nitrogens (Scheme 154) (488). Alkylation of l-alkyl-3-(2-thiazolyl)urea from its derived anion formed by NaH gives 259 (Scheme 155). 

Propylene Urea Resins. In similat fashion to ethyleneurea, dimethyl-olpropyleneurea [3270-74-4] [l,3-bis(hydroxymethyl)tetrahydro-2-(m)-pyrimidinone] is the basis of propyleneurea—formaldehyde resin [65405-39-2], Its preparation is from urea, 1,3-diaminoptopane [109-76-2] and formaldehyde. 

Pesticide Solvent. The majority of organic fungicides, insecticides, and herbicides (qv) are soluble in DMSO, including such difficult-to-solvate materials as the substituted ureas and carbamates (see Fungicides, agricultural Insect control technology Pesticides). Dimethyl sulfoxide forms cosolvent systems of enhanced solubiUty properties with many solvents (109). 

Uracil reacts with hydrazine to give pyrazol-3(2if)-one (944) and urea N-methyl- and dimethyl-hydrazine behave similarly to give the 2-methyl- and 1,2-dimethyl derivatives. The reactions of hydrazines with uridine and related nucleosides and nucleotides is well studied (67JCS(C)1528). The tautomerism and predominant form of uracil are discussed in Section 2.13.1.8.4. 

In contrast to the above additions A-allyl- and substituted A-allyl-amides, -urethanes, -ureas and -thioureas undergo intramolecular cyclization only in 6(3-96% sulfuric acid to give the corresponding oxazolinium and thiazolinium salts. Treatment of these cations with base yields 2-oxazolines and 2-thiazolines in moderate to good yields. The reaction is illustrated by the conversion of A-2-phenylallylacetamide (342) into 2,5-dimethyl-5-phenyl-2-oxazoline (343) in 70% yield 70JOC3768) (see also Chapter 4.19). 

Dichlorophenyl)-l,1-dimethyl urea (Diuron) [330-54-1] M 233.1. Crystd four times from 95% EtOH [Beck et al. J Am Chem Soc 108 4018 1986]. 

Columns can be washed with solvents and solvent combinations suitable to remove adsorbed contaminants. When considering the adsorption of analytes, think not only of the diol functionality, but also of the adsorption to residual silanols. Often, the injection of small amounts (500 /d) of dimethyl sulfoxide removes contamination that has accumulated on the column. Aqueous solutions of sodium dodecyl sulfate, guanidine hydrochloride, or urea are compatible with Protein-Pak columns. 

In the hands of Collie and Tickle in 1899 this reaction gave the first crystalline pyrylium salts. The salt character of the compounds was proved by conductivity measurements the basicity of 2,6-dimethylpyrone was found to be a little higher than that of urea. Basicities of other pyrones decrease in the order 2,6-dimethyl-> 2-phenyl-6-methyl-> 2,6-diphenylpyrone, paralleling the dipole moments. These hydroxypyrylium salts hydrolyze in water to pyrones. " The formation of salts of 2,6-dimethylpyrone with organic acids was investigated by Kendall,and with mineral acids by Cook. 11 ... 

Preparation of Di-(0-Pheny/-a,a-Dimethylethyl)Urea 3.5 grams of a,a-dimethyl-(3-phenyl-propionamide in 420 cc of water was added to a solution of 87.5 grams of potassium hydroxide and 35 grams of bromine in 350 cc of water. After 2 hours at 60°C, the product was obtained on crystallization from ethanol, melting at 184°C. 

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