Amino side groups

We have prepared a copolymer-bearing amino side group and used it either alone or in combination with BP to initiate the photopolymerization of MM A [89]. The gel permeation chromatography (GPC) plot of PMMA initiated by the former system showed a bimodal distribution of molecular weight because both the radicals produced initiate polymerization as follows ... 

The second approach to linear polysilanes is based on the modification of polysilanes prepared by the reductive coupling method. The severe conditions of this reaction allow only alkyl or aryl substituents at the silicon atom in the starting dichlorosilane. Therefore only alkyl or aryl substituted polysilanes are known. We have successfully prepared new polysilanes with pendant alkoxy and amino side groups. This approach allows fine tuning of the properties of... 

Wurtz coupling of dibutylaminotrimethyl-l-2-dichlorodisilane forms a partially networked polymer.79 This networked polymer shows an absorption maximum at 360 nm, that is 30 nm red shifted relative to the absorption of poly (dialkylsilanes). The shift is due to the nonbonding electron pair of the amino substituents extending the a-conjugation of the silicon backbone. Two broad emission bands at 440 nm and 400 nm are observed and assigned to the network silicon units and the linear silicon chains, respectively. The unusual photophysical properties arise from both the amino side groups and the networked structure. 

Dorzolamide was the first commercially available topical CAI to show significant ocular hypotensive activity in hmnans.The addition of an alkyl amino side group allows this compoimd to alternate between an acidic and basic form. This property enhances both lipid and water solubility, thereby allowing increased corneal and scleral penetration. 

Synthesis and Photoluminescence of Cyclohexasilanes Bearing Siloxy-and Amino Side Groups... 

Sulfonation Via the Use of Sultones. Direct sulfonation is generally not possible when aliphatic side chains are present. However, sulfonated aliphatic side chains can be produced via the reactions of polyphosphazenes that bear aliphatic amino side groups widi sultones (55) (Scheme IV). The pendent terminal amino units must be introduced by a protection-deprotection route (see later). 

Figure 15 shows the 3D plot of s relative to neutralized chitosan, evidencing the a process in the high temperature-low frequency range whose Arrhenius-type temperature dependence of relaxation times is shown in the inset. The secondary process observed in the low-temperature region is due to local main chain motion via the glycosidic bond, influenced by the amino side group (see [149] for discussion). 

The synthesis of an ampholytic block copolymer, namely PMAA-PDEAEMA, carrying carboxylic and tertiary amino side groups, has been also realized by ATRP, as has been reported by Tam and coworkers [15]. Initially, the synthesis of the tert-butyl protected PMAA block was performed using p-toluenesulfonyl chloride as an initiator and CuCl complexed with N,N,N ,N ,N ,N -hexamethyltriethylenetetraamine as a catalyst in 50 vol % anisole at 90 °C. The obtained polymer was used as the macroinitiator for the subsequent polymerization of the second monomer, DEAEMA, imder similar reaction conditions. Figure 3. The resulted copolymer was subjected to selective hydrolysis, imder acidic conditions, for removal of the tert-butyl protecting group. 

Amines are simple compounds derived from ammonia (NH3) in which one or more hydrogen atoms is replaced by carbon. Replacement of one, two or three hydrogen atoms results in primary, secondary and tertiary amines respectively. Amino acids and alkaloids are derived from amines however, in one group of alkaloids the only nitrogen atoms occur in the amino side group attached to a benzene ring—they are not heterocyclic. Hence alkaloidal amines are often regarded as pseudo alkaloids . The precursors for alkaloidal amines are aromatic amino acids—phenylalanine, tyrosine and tryptophan. 

The thermal stability, also, depends on the types of side groups present. Amino side groups usually condense at high temperatures to yield crosslinked matrices. 

Amino side groups give rise to higher Tg values than do alkoxy side groups, and this can be attributed to the enhanced steric effects associated with -NR2 groups, or the opportunities for hydrogen bonding when -NHR residues are present. 

---