2-Chloro-1,4-diazine

By analogy with 4- and 2-chloropyrimidines, it is reasonable to predict the relation 5-as-triazinyl > 3-os-triazinyl. The substantial activation by additional ring-nitrogens, especially in the optimal 1,3,6 arrangement, is evident in the fact that chloro-s-triaasines, even when deactivated by one or two substituents, are equally or more reactive than many chloro-azines or chloro-diazines. For example, 2,4,6-trichloro-s-triazine reacts with various nucleophiles to give monosubstituted derivatives at 0-10°, disubstituted at 20-30°, and trisubstituted at... 

Metalation of Sensitive Heterocycles and Functional Group Tolerance. Several sensitive heteroarenes such as pyridazines, pyrimidines, and pyrazines can be cleanly zincated at 25 °C using the nuld hase TMPZnCl-LiCl (eq 2). Thus, the treatment of 3,6-dichloropyridazine with TMPZnCl-LiCl (1.1 equiv, 25 °C, 30 min) readily leads to the corresponding zincated species with full conversion. Similarly, the zincation of other sensitive chloro-diazines such as 4,6-dichloropyrimidine or 2,6-dichloropyrazine furnishes the corresponding zincated arene at room temperature, also in excellent conversion. ... 

Diazine A -oxides can be regioselectively formed with H2O2 in formic acid as exemplified by the reaction of 2-chlorobenzo[/]cinnolines, 2-chloro-5,6-dihydrobenzo[/]cinnolines, and 3-chloro-9//-indeno[2,l-f]pyridazines <2000AP341>. This area was extensively discussed in CHEC(1984) <1984CHEC(2)1>. 

In the sense of an inter molecular amination with heterocyclic amidine derivatives, such as amino azines and diazines, and 2-chloro-3-iodopyridines followed by an intramolecular amination, Maes and coworkers [93] have established a facile synthesis of dipyrido[l,2-a 3, 2 -d]imidazole and its benzo-and aza-analogs 101-106 (Scheme 36). 

Chloro - 3 - dichloromethyl -3,4 - dihydro - 2H-1,2,4- benzothia-diazine-7-sulphonamide 1,1 -dioxide C8H8Cl3N304S2 = 380.6 CAS-IS3-67-5... 

Gohlke, H., Giindisch, D, Schwarz, S., Seitz, G., Tilotta, M.C., and Wegge, T. 2002. Synthesis and nicotinic binding studies on enantiopure diazine analogues of the novel (2-chloro-5-pyridyl)-9-azabicyclo[4.2. l]non-2-ene UB-165. J Med Chem 45, 1064-1072. 

HIV-1 revcr.se transcriptase inhibitor (L-7.38,372) 6-chloro-4-cycIopropyl-4- 2-(2-pyridyl)cthinyl]-3,4-dihydro-benz.o-1,3-diazin- 1 H)-2-one polyacrylamide of (S)-Phc ethyl ester (Chiraspher) 1197]... 

With azines the situation is varied. In the radical cations of pyridine and diazines the semi-occupied orbital is largely confined to the nn orbital(s) (see Scheme 2, structure 2), while the radical cation is of the n type with monoazanaphthalenes, -phenanthrenes and -anthracenes. The situation might change with substitution. As an example, alkylpyridine radical cations are of the n type, like the parent compound, whereas for the 2,5-dimethyl, 2-chloro, and 2-bromo derivatives the structure is of the n type [13]. Likewise, with benzo[c]cinnoline the parent compound and its alkyl derivatives give an n radical cation, but with some dimethoxy derivatives a n structure is found [14] and a switch from n to 7t structure occurs also in passing from 1,2,4,5-tetrazine to its 3,6-diamino derivatives [15]. 

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