C*Carbamylation

N-(halogenoformyl)imino-halides 28, 383 isocyanates 26,295 C-Carbamylation, homolytic, of heterocyclics 25, 480 Carbamyl azides... 

Carbamyl chlorides, N-deal-kylation via - 32, 15 N- C-Carbamyl group migration 31, 983 Carbamyl halides... 

Carbamides s. Ureas C-Carbamylation with carbamyl cyanides 14, 885 N-Carbamylation 4, 413... 

The most important commercial process is the reaction of MDA with an excess of phosgene to form the corresponding isocyanate, 4,4 -methylene-diphenyldiisocyanate, MDI, C H qN202- The reaction proceeds through the formation of a primary carbamyl chloride that is decomposed with heating and the removal of HQ. 

C rb myl tion. Modification of the amino-terminal groups of hemoglobin (Hb) by the carbamylation reaction using isocyanic acid [75-13-8]... 

Hlasta and Deng have developed a two-step solid-phase method for the decoration of azoles at C-2 [188]. First, imidazole was loaded onto a polystyrene-bound carbamyl chloride via a benzaldehyde bridge (Fig. 40). The 2-substi-tuted imidazole was efficiently cleaved in good yields in the presence of various nucleophiles (i.e., water, alcohols, and amines), trifluoroacetic acid, and boron trifluoride under microwave irradiation in a closed vessel at 120 °C for 5 min. 

C31H36N2(V0.03 Ca2+H20 7-(3-0-Carbamyl-5,5-di-C-methyl-4-0-methyl-a-L-lyxopyranosyl)-4-hydroxy-3-[4-hydroxy-3-(3-methyl-2-butenyl)benzamido]-8-methylcoumarin, monohydrate (novobiocin, monohydrate) (NIVBIO)270... 

By photolysis of iV-chloro-4-butenyloxazolidin-2-one 350 at 300 nm in CH2C12 at — 78 °C, the intermediate carbamyl radical 351 underwent 5-diastereomeric mixture of bicyclo[3.3.0]azaoctanes 352 (Scheme 51) <1999T3495>. 

Diphenyl carbamyl diethanolamine, (C H gN-CO.NfCHgCHaOH) crysts (from. 

N-carbamyl-/ -aminoisobutyric acid is prepared by the alkaline hydrolysis of dihydrothymine [10]. Dissolve dihydro thymine in 0.1 M NaOH and hydrolyze at 37°C for 1 h. Neutralize the solution with HC1. The stable-isotope-labeled 2H6-N-carbamyl-/Taminoisobutyric acid and 15N2/3 4C4-N-carbamyl-/ -alanine are prepared by alkaline hydrolysis of the corresponding stable-isotope-labeled dihydropyrimidines. 

Fig. 7.1.3 High-performance liquid chromatography/electron spin ionization-tandem mass spectrometry profiles of urines from patients with a dihydropyrimidine dehydrogenase (upper panel), dihydropyrimidinase (middle panel) and a /Tureidopropionase deficiency (lower panel). The inserts show the profiles of a control urine, note the differences in scale. N-C-fi-ala-nine N-Carbamyl-j6-alanine, N-C-fi-AIB N-carbamyl-/Taminoisobutyric acid...

Bohme and Schiirhoff131 have measured the rate of hydrolysis of ethyl chloroformate and found it to be quite slow (kx = 2.0x 10"4sec-1 in water at 25°C). Hall118, investigating the hydrolysis of ethyl chloroformate and dimethyl carbamyl chloride, found the rate sequence for neutral hydrolysis to be... 

AN76 C3H nC 1N2O (CsHnC 105) see A0l6 l+-carbamyl -1-ethyl -pyridtnium chloride T6NJ A2 DVZ G MeCN PY Bu4NC104 - - - DME/SCE — C=0.1-1... 

Temperature is also an important parameter for controlling the resolution of enantiomers in HPLC. The enthalpy and entropy control of chiral resolution on antibiotic CSPs is similar to the case of polysaccharide-based CSPs (Chapter 2). Armstrong et al. [1] have studied the effect of temperature on the resolution behavior of proglumide, 5-methyl-5-phenylhydantoin and A-carbamyl-D-pheny-lalanine on the vancomycin column. The experiments were carried out from 0°C to 45°C. These results are given in Table 6 for three chiral compounds. It has been observed that the values of k, a, and Rs for the three studied molecules have decreased with the increase in temperature, indicating the enhancement of chiral resolution at low temperature. In another work, the same workers [22] have also studied the effect of temperature on the resolution of certain amino acid derivatives on the teicoplanin chiral stationary phase. They further observed poor resolution at ambient temperature, whereas the resolution increased at low... 

Fig. 6.11. The (Krebs-Henseleit) ornithine cycle. Numbers refer to enzymes as follows. (1) Carbamyl phosphate synthetase (E.C.2.7.2.a). (2) Ornithine transcarbamylase (E.C.2.1.3.3). (3) Arginino-succinate synthetase (E.C.6.3.4.5). (4) Arginino-succinate lyase (E.C.4.3.2.1). (5) Arginase (E.C.3.5.3.1). (After Smyth, 1969.)...

Stadtman has demonstrated (42) the conversion of carbamyl phosphate and acetate to acetyl phosphate, catalyzed either by a crude lysine system or by a purified acetate kinase from C. sticklandii. ADP and... 

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