1 - cytosine triazines

The 5-aza analog of cytosine could be taken as 4-amino-2-oxo-l,2-dihydro-1,3,5-triazine (40) which was prepared by the reaction of... 

Two types of addition to pyrimidine bases appear to exist. The first, the formation of pyrimidine photohydrates, has been the subject of a detailed review.251 Results suggest that two reactive species may be involved in the photohydration of 1,3-dimethyluracil.252 A recent example of this type of addition is to be found in 6-azacytosine (308) which forms a photohydration product (309) analogous to that found in cytosine.253 The second type of addition proceeds via radical intermediates and is illustrated by the addition of propan-2-ol to the trimethylcytosine 310 to give the alcohol 311 and the dihydro derivative 312.254 The same adduct is formed by a di-tert-butyl peroxide-initiated free radical reaction. Numerous other photoreactions involving the formation by hydrogen abstraction of hydroxyalkyl radicals and their subsequent addition to heterocycles have been reported. Systems studied include 3-aminopyrido[4,3-c]us-triazine,255 02,2 -anhydrouri-dine,256 and sym-triazolo[4,3-fe]pyridazine.257 The photoaddition of alcohols to purines is also a well-documented transformation. The stereospecific addition of methanol to the purine 313, for example, is an important step in the synthesis of coformycin.258 These reactions are frequently more... 

Binder et al. [92,93] have reported on the formation of poly(etherketone) poly(isobutylene) networks formed by the respective endgroup-modified telechelics. The relevant interactions investigated relied on the 2,6-diamino-1,3,5-triazine/thymine and the much weaker cytosine/2,6-diamino-1,3,5-triazine-modified polymers (Fig. 18). In addition to the pure hydrogenbonding interaction, phase-separation energies resulting from the strongly microphase separating PEK- and PIB polymers were expected. The association behavior was followed in solution via NMR-association experiments. 

Aminocoumaiins Aminoindazoles Aminopurines Aminopyridines Aminopyrimidines Aminouracils Aminopyrazines Aminopytidazines Aminoquinazolines Amino-1,2,4-triazines Amino-1,2,4-triazoles Aminopteridines Aminobenzimidazole Aminopyrimidopyrimidines Aminobenzotriazines Cytosines... 

Many supramolecular polymers are derived directly from DNA s nucleobases adenine (A), cytosine (C), guanine (G), and thymine (T) [9]. Although each nucleobase can homodimerize, as described in the previous section, heterodynamic complexation is favored to different degrees. The G-C complex involves three H-bonds, and it is two or three orders of magnitude more stable than the A-T complex, involving only two H-bonds. 2,6-Diamino triazine derivatives strongly associate with thymine, and this pair has formed the basis for many studies. 

Cyanine dyes 393 Cyanocobalamin 233, 557 Cyanuric chloride see 2,4,6-trichloro-1,3,5-triazine Cyanuric acid 512 Cyclazine 153 Cycloserine 196 Cytisine 423 Cytokinin 480 Cytosin 470... 

---