1- Methylurea

The acetylmethylurea is converted by concentrated hydrochloric acid into methylurea the latter yields nitrosomethylurea with nitrous acid ... 

An alternative method of preparation involves the interaction of methylamine hydrochloride with urea to give methylurea, followed by interaction with nitrous acid as above ... 

Meihylamine hydrochloride method. Place 100 g. of 24 per cent, methyl-amine solution (6) in a tared 500 ml. flask and add concentrated hydrochloric acid (about 78 ml.) until the solution is acid to methyl red. Add water to bring the total weight to 250 g., then introduce lSO g. of urea, and boil the solution gently under reflux for two and three-quarter hours, and then vigorously for 15 minutes. Cool the solution to room temperature, dissolve 55 g. of 95 per cent, sodium nitrite in it, and cool to 0°. Prepare a mixture of 300 g. of crushed ice and 50 g. of concentrated sulphuric acid in a 1500 ml. beaker surrounded by a bath of ice and salt, and add the cold methylurea - nitrite solution slowly and with mechanical stirring and at such a rate (about 1 hour) that the temperature does not rise above 0°. It is recommended that the stem of the funnel containii the methylurea - nitrite solution dip below the surface of the acid solution. The nitrosomethylurea rises to the surface as a crystalline foamy precipitate. Filter at once at the pump, and drain well. Stir the crystals into a paste with about 50 ml. of cold water, suck as dry as possible, and dry in a vacuum desiccator to constant weight. The yield is 55 g. (5). 

The carbonylation of some alkyl halides such as iodocyclohexane (911) can be carried out under neutral conditions in the presence of N,N,N.N-tetre,-methylurea (TMU), which is a neutral compound, but catches generated hydrogen halide. Molecular sieves (MS-4A) are used for the same pur-pose[768]. Very reactive ethyl 3-iodobutyrate (912) is carbonylated to give ethyl methylsuccinate (913) in the presence of TMU. The expected elimination of HI to form crotonate, followed by carbonylation, does not occur. 

The reaction conditions can be varied so that only one of those monomers is formed. 1-Hydroxy-methylurea and l,3-bis(hydroxymethyl)urea condense in the presence of an acid catalyst to produce urea formaldehyde resins. A wide variety of resins can be obtained by careful selection of the pH, reaction temperature, reactant ratio, amino monomer, and degree of polymerization. If the reaction is carried far enough, an infusible polymer network is produced. 

The primary synthesis of alkoxypyrimidines is exemplified in the condensation of dimethyl malonate with O-methylurea in methanolic sodium methoxide at room temperature to give the 2-methoxypyrimidine (854) (64M207) in the condensation of diethyl phenoxymalonate with formamidine in ethanolic sodium methoxide to give the 5-phenoxypyrimidine (855) (64ZOB1321) and in the condensation of butyl 2,4-dimethoxyacetoacetate with thiourea to give 5-methoxy-6-methoxymethyl-2-thiouracil (856) (58JA1664). 

Linear descendants of the antimicrobial sulfonamides, the orally active sulfonylureas continue to be of interest as alternatives to insulin injections in patients with adult-onset diabetes. Tolpyrramide (153) is synthesized from unsymmetrical O-methylurea... 

Reactions were carried out in a glass vessel closed with a septum cap. Neither molecular sieve nor drying gas was used. The glycosyl donor (0.41 mmol, 1 equiv) in CH2C12 (3 ml) was treated with Ph3P (3 equiv) and CBr4 (3 mol equiv) and stirred for 3h at room temperature. Then, the N,N-tetra-methylurea (300 pi) and the glycosyl acceptor (3 equiv) were added and stirred at room temperature. The reaction was monitored by TLC analysis until the bromide donor was... 

Chlorobromuron (3,4 (bromo-3-chloro-phenyl) 1-1 methoxy 1-methylurea)... 

Miscellaneous urea herbicides (chlorobromuron (3,4(bromo-3-chlorophenyl)-1 -methoxy-1 -methylurea), Chlorotoluron (3(3 chlorotoluyl) dimethyl urea), Diuron (N-(3,4 chlorophenyl) N,N dimethyl urea), Monolinuron (3(4, chlorophenyl-1-methoxy-1 -methylurea), Linuron (3,(3,4 dichlorophenyl)-1 -1 -methoxy-1 -methylurea) Chloroxuron (3, (3,4 dichlorophenyl-1,1 dimethylurea)... 

The potential triple A D D D A A interaction between cytosine and bis(amidino-0-methylurea)ethane, when co-ordinated to copper(II), is shown in Scheme 12 (l.h.s.). Alternative complementary interactions between amidino-O-alkylureas and DNA pyrimidine bases include the double D A A-D interaction with thymine shown in Scheme 12 (r.h.s.). 

Reaction with amines gives substituted ureas (cf. methylurea p. 271) —with hydrazine for example, semicarbazide ... 

It is estimated that over 100,000 acres in Hawaii and some 250,000 acres in Louisiana each year are treated with herbicides, mostly 2,4-D and TCA (sodium salt of trichloroacetic acid), for pre- and postemergence weed control. Johnson grass on ditch banks on some 50,000 to 75,000 superficial acres in Louisiana is controlled with sodium chlorate or TCA. Some trials with CMU [3-(p-chlorophenyl)-l,l-di-methylurea] are in process. Florida cane growers use 150,000 pounds of 2,4-D amine salt of Karmex W on 43,000 acres of cane and anticipate using up to 100,000 pounds per year. Of the growers in Puerto Rico, 60% are said to use herbicides as either pre- or post-emergence sprays. 

The purpose of the present study was to investigate the adsorption behavior of the metobromuron (3-(4-bromophenyl)-l-methoxy-l-methylurea) at the high area ACC from aqueous solutions and thus the possibility of removal of that pesticide from waters. 

Under aerobic conditions, mixed cultures isolated from pond water and sediment degraded diuron (10 pg/mL) to 3-(3-chlorophenyl)-l,l-dimethylurea (CPDU), 3,4-dichloroaniline, 3 (3,4-dichlorophenyl)-l-methylurea, carbon dioxide, and a monodemethylated product. The extent of biodegradation varied with time, glycerol concentration, and microbial population. The degradation half-life was <70 d at 30 °C (Ellis and Camper, 1982). 

Chlorophenoxyacetic acid, see 2,4-D 4-(4-Chlorophenoxy)aniline, see Chlnrnxiiron IV-(4 -Chlorophenoxy) phenyl-A -methylurea, see... 

Chlorophenyl)-l-methylurea, see Monuron lV-(3-Chlorophenyl)propanamide, see Propanil... 

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