Atomic Rabbit

Polydioxolanes exist predominantly in gauche conformation, because in the anti- form the polymer would be of higher energy due to the repulsion of the non-bonded electrons of the oxygen atoms ( rabbit ears effect) ... 

There are two reasons for this First, there are two destabilizing syn-parallel interactions between the four pairs of unshared electrons on two oxygen atoms (rabbit-ear effect) and second, in the gauche-gauche conformation there are two stabilizing ew fo-anomeric effects. 

Cover of Atomic Rabbit 9 (Charlton Comics, 1957). Atomic Rabbit was one of a cadre of atomic animals in the 1950s and 1960s that helped recast "the atom" from a source of fear to one of strength and justice. 

Alkylamines and diamines are generally classified as corrosive to the skin based on results from laboratory animal (rabbit) studies performed in accordance with the Department of Transportation (DOT) test method (84) rabbits are considered to be especially sensitive to alkylamines which even at low concentrations can induce skin redness and swelling. Oleylamine has been shown to induce mild to moderate skin irritation in laboratory rats when appHed at a concentration of 0.3% in mineral oil (Chemical Manufacturer s Association, 1985). Fatty amines which contain alkyl chains of 10—14 carbons are considered more irritating than related products which contain alkyl chains of 14—18 carbon atoms. Ethoxylation generally decreases the irritation potential of alkylamines. 

Oae and coworkers oxidized several diaryl, dialkyl and alkyl aryl sulfides to their corresponding sulfoxides using purified cytochrome P-450 obtained from rabbit liver microsomes138. In agreement with expectations, this enzyme did not exhibit much stereospecificity. Some examples including the observed e.e. values are shown by 121-125. A model was proposed to account for the absolute configurations of the sulfoxides produced (126). The sulfur atom is preferentially oxidized from the direction indicated. 

Attention has been drawn to the potential of phosphoric acid anhydrides of nucleoside 5 -carboxylic acids (14) as specific reagents for investigating the binding sites of enzymes. For example, (14 B = adenosine) inactivates adenylosuccinate lyase from E. coli almost completely, but has little effect on rabbit muscle AMP deaminase. The rate of hydrolysis of (14) is considerably faster than that of acetyl phosphate, suggesting intramolecular assistance by the 3 -hydroxyl group or the 3-nitrogen atom. 

It was next important to determine the effect of altering the groups adjacent to the fluorine atom. Thus methyl a fluoro propionate (II) and a-fluoroisobutyrate (III) were prepared. Both these compounds were relatively non-toxic. The first, for example, at a concentration of 1/20,000 (0-24 mg./l.) killed 0/23 of a batch of 3 rabbits, 4 guinea-pigs, 6 rats and 10 mice. The second at the same concentration killed only 2/23. 

Chloro-2-fluoroethane, easily obtained3 from fluoroethanol, was found to be non-toxic. A concentration of 0-184 mg./l. failed to kill any animals, whereas a similar concentration of fluoroethanol or of methyl fluoroacetate would have killed some 50 per cent of a batch of rabbits, guinea-pigs or rats. The chlorine atom in chlorofluoroethane was found to be un-reactive towards a variety of reagents, and this fact no doubt... 

Fluoroethyl fluoroacetate is a compound of considerable toxicity. Its l.c. 50 for rabbits (inhalation) is 0-05 mg./l., i.e. about half as great as for M.F.A. It is therefore placed in class A. Other factors apart from hydrolysis to fluoroethanol and fluoroacetic acid appear to be operative, and it seems that the molecule is toxic per se. The related fluoroacetylimino-2-fluoro-ethyl ether hydrochloride, [CH2F C( NH2) O CH2 CH2F]+CT, is also placed in class A. This is understandable as it is readily hydrolysed by water to 2-fluoroethyl fluoroacetate. Other fluoroacetylimino ether hydrochlorides containing, however, only one fluorine atom fall into class B, as does also fluoroacet-amidine hydrochloride itself. 

Figure 16. Influence of one, two, or three chlorine atoms in the phenyl ring on blood pressure in anaesthetized rabbits...

The first systematic study of the metabolic hydrolysis of primary aliphatic amides was carried out by Bray et al. in 1950 [1]. The substrates were incubated in rabbit liver preparations for 5 h at 37°. In Fig. 4.2, the effect of chain length on the degree of hydrolysis of amides containing 1 to 18 C-atoms (4.1) is shown. The extent of hydrolysis was very small for the first three homo-... 

In order to investigate the active sites of these proteins, laccases I and III were subjected to ESR (electron spin resonance) spectroscopic analysis. The ESR spectra shown in Figure 5 indicate clear differences in peaks 2 and 6 which support the concept that the copper atoms in laccases I and III have different conformations in each molecule. Furthermore, immunological similarity between laccases I and III was also investigated. Antibody specific for laccase III was prepared from rabbit serum by conventional methods. When applied to Ouchterlony diffusion plates containing laccase I, no precipitation lines developed (Figure 6). This result showed that there were no conserved epitopes on the surfaces laccases I and III. 

This was verified by Kobuch and Hoerauf by histological studies [36,28]. Different fluorinated compounds with a linear backbone of 8 C-atoms and a different degree of fluorination were filled into the vitreous cavity of vitrectomised rabbit eyes. 

Deamination. Amine groups can be removed oxidatively via a deamination reaction, which may be catalyzed by cytochromes P-450. Other enzymes, such as monoamine oxidases, may also be involved in deamination reactions (see below). The product of deamination of a primary amine is the corresponding ketone. For example, amphetamine is metabolized in the rabbit to phenylacetone (Fig. 4.27). The mechanism probably involves oxidation of the carbon atom to yield a carbinolamine, which can rearrange to the ketone with loss of ammonia. Alternatively, the reaction may proceed via phenylacetoneoxime, which has been isolated as a metabolite and for which there are several possible routes of formation. The phenylacetoneoxime is hydrolyzed to phenylacetone. Also N-hydroxylation of amphetamine may take place and give rise to phenylacetone as a metabolite. This illustrates that there may be several routes to a particular metabolite. 

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