Containing Three Nitrogen Atoms

Pyrido[2,3-/ ]pyrazine Pyrido[3,4-rf]pyrimidine Pyrido[2,3-tf]pyridazine 

There are 12 isomers for compounds containing two rings with two nitrogens in each (excluding those compounds with nitrogen bridgeheads). All are very unreactive, and the only one of significant interest is pteridine (11.39). 

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Diacylhydrazines (32) on heating with a primary amine undergo cyclization to the 1,2,4-triazole derivative (38). It is assumed that the amidrazone (37) is an intermediate in the reaction. Most practical syntheses of 1,2,4-triazoles now utilize an amidrazone or a derivative of this alicyclic intermediate containing three nitrogen atoms, and these variations are discussed in Chapter 4.12. 

The following compound contains three nitrogen atoms. Rank them in order of increasing basicity. 

RING SYSTEMS CONTAINING THREE NITROGEN ATOMS... 

IX. Reduction of Heterocycles Containing Three Nitrogen Atoms 89... 

In the case of a polymer, and model, containing three nitrogen atoms ... 

Triazine A six-membered heterocyclic compound containing three nitrogen atoms. For example, 1,3,5-triazine is illustrated below. 

Triazole An aromatic five-membered ring that contains three nitrogen atoms and two carbon atoms. Isomeric with osotriazole. 

Hi. Containing three nitrogen atoms. Analogous condensation reac-tions " have been used for the synthesis of triazoles and some examples are shown (Scheme 20, Eqs. 54, 55, 56, 57, and 58 "). Oxadiazoles may also be used as precursors (Scheme 20). 

The structure of (AAf-diethylnicotinamide)cadmium dithiocyanate consists of a three-dimensional network linked by bridges of thiocyanate anions and nicotinamide molecules. The co-ordination sphere of the metal atom contains three nitrogen atoms (Cd-N from 2.292 to 2.355 A), two sulphur atoms (Cd-S at 2.621 and 2.704 A), and one oxygen atom (Cd-O at 2.373 A). The nicotinamide molecule co-ordinates through the pyridine nitrogen atom and the amide carbonyl group. 

Triazoles are five-membered aromatic heterocycles that contain three nitrogen atoms located at the 1,2,3 or 1,2,4 positions in the ring. A large munber of ionic compounds that contain a triazole derivative are described as energetic materials. 

Triazoles are similar to triazines in that they also contain three nitrogen atoms in their ring structures, though they have only two carbon atoms in the ring structure. Amitrole and triadimefon are commonly used triazoles. Different groups of atoms that branch off the central ring structure determine the activity of the compound. The triazole compounds are systemic fungicides that inhibit the s)mthesis of a form of vitamin D. Most triazole compounds are stable in water. 

Five-Membered Ring Heterocycles Containing Three Nitrogen Atoms. Starting with Rink amide resin 341, 4 equiv of Fmoc-amino acid 342 was used in the presence of 4 equiv of ED AC (1 -ethyl-3-(3-dimethylaminopropyl)carbodiimide) and HOBt in DMF overnight (Scheme 9.40). After removal of the Fmoc group with 20%... 

Pyrridazinoindoles can be considered as azaanalogs of different caibolines, and especially p- and y-, the condensed ring system of which represent the basis of many compounds of high physiological activity. Therefore the unified aromatic system of isomeric pyrridazinoindoles containing three nitrogen atoms in different positions and their derivatives have attracted great attention of researchers. 

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