Carbamoyl moiety

The major toxin, gonyautoxin-III was degraded to locate the radioactivity in the carbamoyl moiety. Thus gonyautoxin-III was converted to saxitoxin by treating with zinc and hydrochloric acid (8), which was then hydrolyzed with 6.7 N HCl to decarbamoylsaxitoxin and carbon dioxide (9). About one-third of the total activity (28%) was found to be associated with the released carbon dioxide and the rest with decarbamoylsaxitoxin (Scheme 2). The result seems to be in Scheme 2... 

Although OPPs and carbamates exhibit very similar modes of action in various animal species, i.e, acetylcholinesterase inhibition in the CNS with resulting paralysis—there is an important difference between the two classes of pesticides. Carbamates do not require metabolic conversion prior to exhibiting their toxicity. Furthermore the enzyme activity may at times be rapidly regenerated by reversal of inhibition. The kinetics of the inhibition (carbamoylation) reaction have been well studied in it electrophilic carbamoyl moieties form covalent bonds with enzyme esteratic sites. This is followed by carbamate transfer of an acidic group to the site to yield the acetylated enzyme complex (ref. 176). 

ATCase and ornithine carbamoyltransferase (OTCase) catalyze analogous reactions. ATCase transfers the carbamoyl moiety from carbamoyl phosphate to aspartate, and OTCase transfers the carbamoyl moiety from carbamoyl phosphate to ornithine. They both share a common N-terminal functional domain, which binds carbamoyl phosphate. The C-terminal domains of these enzymes are structurally similar but have... 

One of the most important steps in the SAR study was to assess the optimal arrangement of sulfur and oxygen atoms in the carbamoyl moiety. Data in Table I show that compounds 5 and 6, both thiolesters, were most effective. Clearly, the confplete loss of activity in carbamate 8 highlighted the importance of sulfur in the molecule. 

In the biosynthesis of both pyrimidine and urea (or arginine) (Chapter 17), carbamoyl phosphate is the source of carbon and nitrogen atoms. In pyrimidine biosynthesis, carbamoyl phosphate serves as donor of the carbamoyl group to aspartate with the formation of carbamoyl aspartate. In urea synthesis, the carbamoyl moiety of carbamoyl phosphate is transferred to ornithine, giving rise to citrulline. 

Giacobbe, S., Di Fabio, R., Baraldi, D., Cugola, A., Donati, D., 1999. Synthesis of substituted indole-2-carboxylates versatile introduction of a carbamoyl moiety at the C-position. Synth. Commun. 29, 3125-3135. 

Natural substrate (guanidinium) and inhibitors (carbamoyl) differ by the presence or absence of a positive charge on this part of the molecule. Thus, addition of water (as OH ) to the carbamoyl moiety and hydrolysis of the inhibitor would result in the development of charge rather than in its dispersal (as for the natural substrate ) in the partially hydrophobic environment of the active site. This explains why carbamoyl sarcosine acts as inhibitor for creatinase. In succinamic acid, the central NCH3 is replaced by CH2 and the proton transfer reaction (step 3) cannot occur. 

Carbamazepine essentially contains a dibenzazepine ring system with a carbamoyl moiety hooked on to the nitrogen atom. 

The concept of structural modification amongst the aminoalcohol carbamates has crept up due to the introduction of non-polar functions on the unsubstituted N of the carbamoyl moiety in the following general formula ... 

Carmofur 193 is a chemotherapy drug that is given as a treatment for some types of cancer and orally active cytostatic derivative of 177. The introduction of carbamoyl moiety into 177 significantly affects the toxicity and tumor affinity of 177. ... 

An unusual rearrangement of the carbamoyl moiety was reported by Hill et The reaction of the iron trifluoromethyl complex Fe( -OCNTr2)(CF3)(CO)2(PPh3) with KTp led to the formation of the novel ferraoxetene TpFe /c = C(NTr2) 0CF2 (C0) in 73% yield with loss of CO and PPh3 via a postulated difluorocarbene intermediate (Scheme 5). 

Stereochemistry of the product from this reduction system can be explained in terms of the discussion previously mentioned that methyl benzoylformate is reduced through a transition state where the polar group in the substrate (methoxycarbonyl moiety) interacts with the polar group in the reductant (carbamoyl moiety). This orientation of methyl benzoylformate with the predominant conformer of R-5S which is shown in Fig. 19 should give methyl S-mandelate, which is in accord with the experimental result. The low e.e. value in the reduction of a,a,a-trifluoroacetophenone with R-ZS is due to the low... 

Regarding the effect of the carbamoyl moiety, the compounds having a cycloalkyl group were favorable for acaricidal activity. Among them, cyclohexyl group was the most suitable substituent for the activity. When another alkyl group was introduced into the carbamoyl nitrogen, the activity was decreased remarkably (Table 4). 

Metoplmazine, antiemetic. Dog, rabbit. Dog sulfoxidation, hydro-xylation (M), and hydrolysis of carbamoyl moiety conj. metabolites (glue. ) and UP in urine. Metabolites in feces. Rabbit metabolism same as dog hydrolysis of carbamoyl... 

The reactions of ammonia with either Ru3H(/i-H)( 7-GO)(GO)io or Os3H(/x-H)(GO)n in GD2GI2 solutions yield [NH4][M3( -H)(/i-GO)(GO)io] (M = Ru, Os). When the reactions are followed at low temperature (183 K) by means of H, G, and NMR spectroscopy, it is possible to detect the formation of kinetic products which are derived from the addition of an ammonia molecule to a carbonyl carbon atom. In the Ru case, ammonia is bonded to the bridging carbonyl carbon atom and maintains its wholeness. In the Os system a carbamoyl moiety is formed by transfer of one hydrogen atom from NH3 to the oxygen atom of the carbonyl group to form an O-H bond. ... 

Despite the poor yield of pyrrolizine with carbamoyl moiety 28b and the corresponding configuration of vinylpyrrole 27b, the reaction remains chemoselective among two functional groups capable of participating in the cyclization (amide and nitrile), only the latter is active. 

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