Amino group, 738 table

Nitrogen heterocycles undergo C-allylation in the presence of metalacyclic iridium-phosphoramidite catalysts. Recently, Yu and coworkers reported the C-allylation of indoles with the iridium catalyst derived from LI [86] and from phosphoramidites containing 2-methylindoline- and 2-methyl-l,2,3,4-tetrahydro-quinoline as the amino group (Table 4) [87]. No N-allylation was reported. However,... 

Since the same type of amino acid in a protein can have very different degrees of reactivity, these differences can sometimes be used to classify them into fast and slow, and sometimes even intermediate, degrees of reactivity. When this can be done, there may be only a few amino acids of a particular type in one of these classifications. If one of the amino acids in a classification is essential for the function of the protein, then it may be possible to do a kinetic analysis relating the loss of activity to the modification of residues in that particular class. It is then frequently a simple procedure to determine whether there are one, two, or more amino acid side chains required for activity. This was used to relate losses of activities with numbers of essential amino groups in ovomucoids. Turkey and penguin ovomucoids were easily shown to have one essential amino group (Table V) (27). 

Of particular importance are the carbonyl and amino groups (Table 3.6.1). Each of these has two forms depending on pH an ionized and a nonionized form. This will be discussed further in Section 3.7.4. 

Which of the common amino acids have more than one carboxyl group Which have more than one amino group (Table 20.3)... 

Primary Amines, The spectra of these bases usually possess two bands ( N—H = 3380, 3300 cm ) of medium-to-weak intensity. These bands are assigned to the antisymmetric and symmetric N—H stretching modes, respectively, of the primary amino group (Table 8.17 also see Chapter 8W, IR <=(www) section. Fig. W8.32). 

The introduction of a trimethylsilyl group into an alkyl group increases the base strength, the pKg, values of both trimethylsilyl-methylamine and di(trimethylsilylmethyl) amine being appreciably higher than the values for methylamine and dimethylamine, respectively. The effect diminishes, however, the further the trimethylsilyl group is removed from the amino group (Table 5). 

The deamination in water-acetic acid mixtures, lean in water, is very similar to that in glacial acetic acid (section 5) and Table 13). In the deamination of frattr-/rans-2-decalylamine (axial amino group) (Table 13), the decalol is formed with overall retention of configuration up to a solvent composition of 75 mole % water-25 mole % acetic acid presumably the retention path ((d), equation 146) is one of the chief reaction modes operating. The decalyl acetates (the solvolysis products) are formed with overall inversion of configuration in all the solvent mixtures and the proportion of inveraon increases with water... 

Biological Formation and Reactions of the Amino Group Table 1. Common a-L-amino acids. 

Oxoselenazolines with a 2-(disubstituted amino) group are obtained by the action of a-halocarboxylic acid or rather their esters on N-disubstituted selenoureas (Scheme 63, Table X-14) (27. 67. 68). 

TABLE M4. SUBSITTUTION EFFECTS OUALITATTVE VARIATIONS OF 7T NET CHARGE INDUCED BY THE SUBSTITUTION OF A CHLORINE OR AN AMINO GROUP (123) ... 

The most used EIA reagents conjugate a fluotophote such as fluorescein-isothiocyanate (EITC) or thodarnine—isothiocyanate to antibody (or antigen) free amino groups. Examples of other commonly used fluotophotes for EIA and their spectral characteristics ate presented in Table 3. EIA assays ate available in sandwich and competitive formats similar to EIAs. Unlike EIA kits which can be used directly with visual color deterrnination, EIAs require a fluorometer, and thus ate primarily laboratory-based. 

Monomer Reactivity. The poly(amic acid) groups are formed by nucleophilic substitution by an amino group at a carbonyl carbon of an anhydride group. Therefore, the electrophilicity of the dianhydride is expected to be one of the most important parameters used to determine the reaction rate. There is a close relationship between the reaction rates and the electron affinities, of dianhydrides (12). These were independendy deterrnined by polarography. Stmctures and electron affinities of various dianhydrides are shown in Table 1. 

Sundower Seed. Compared to the FAO/WHO/UNU recommendations for essential amino acids, sunflower proteins are low in lysine, leucine, and threonine for 2 to 5-year-olds but meet all the requirements for adults (see Table 3). There are no principal antinutritional factors known to exist in raw sunflower seed (35). However, moist heat treatment increases the growth rate of rats, thereby suggesting the presence of heat-sensitive material responsible for growth inhibitions in raw meal (72). Oxidation of chlorogenic acid may involve reaction with the S-amino group of lysine, thus further reducing the amount of available lysine. 

Pyridoxal Derivatives. Various aldehydes of pyridoxal (Table 3) react with hemoglobin at sites that can be somewhat controlled by the state of oxygenation (36,59). It is thereby possible to achieve derivatives having a wide range of functional properties. The reaction, shown for PLP in Figure 3, involves first the formation of a Schiff s base between the amino groups of hemoglobin and the aldehyde(s) of the pyridoxal compound, followed by reduction of the Schiff s base with sodium borohydride, to yield a covalendy-linked pyridoxyl derivative in the form of a secondary amine. 

Bis-Pyndoxal Tetraphosphate. A second class of bifunctional reagents, described in 1988, involves two pyridoxal groups linked by phosphates of different lengths (89). As shown in Table 4, the yield of intramolecularly cross-linked hemoglobin increases dramatically with increasing length of the phosphate backbone. It is beheved that the site of reaction of (bis-PL) is between the amino-terminal amino group of one P-chain and the... 

The ahphatic alkyleneamines are strong bases exhibiting behavior typical of simple aUphatic amines. Additionally, dependent on the location of the primary or secondary amino groups iu the alkyleneamines, ring formation with various reactants can occur. This same feature allows for metal ion complexation or chelation (1). The alkyleneamines are somewhat weaker bases than ahphatic amines and much stronger bases than ammonia as the piC values iadicate (Table 2). 

The 3- or 5-aminopyrazoles are the synthons used most frequently. The second heterocyclic ring is created between the amino group and the 1-position (if unsubstituted) or between the amino group and the 4-position. Thus 3-substituted 5-aminopyrazoles react with 1,3-difunctional compounds to afford pyrazolo[l,5-a]pyrimidine derivatives (538) (Table 34). Aminopyrazolinones (R = OH) can be used instead of aminopyrazoles. Similarly 3-aminoin-dazole yields pyrimido[l,2-h]indazoles (539). 

As can be seen from Table 3, only modifications at the 6/3-amino groups have been successful in producing penicillins of medical significance up to this time. Several reviews have dealt with the structure-activity relationship in this area in considerable detail B-80MI51102, B-77MI51106, B-75MI51102) and should be consulted for the actual effects of structural modification on antibacterial activity. 

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