Triazines, nomenclature

According to the triazine nomenclature, 5-azauracil is 2,4-dioxo-l,2,3,4-tetrahydro-l,3,5-triazine (2). The subject index of Chemical Abstracts prefers s-triazine-2,4(lH,3H)-dione. Furthermore, some authors use a name derived from the lactim structure, 2,4-dihydroxy-s-triazine (3). The numbering of the substituents is the same for all these types of nomenclature. 

According to systematic triazine nomenclature, 6-azauracil is 3,5-dioxo-2,3,4,5-tetrahydro-1,2,4-triazine (42). The indexes of the Chemical Abstracts describe it as as-triazine-3,5(2H,4H)-dione. In addition ... 

Detailed appendix on triazine nomenclature, chemical structures, and properties. 

Hsynthesis from, 3, 767 Indenobenzazepines pharmacological properties, 7, 546 Indenone oxide, 2,3-diphenyl-photochromic compound, 1, 385 In deno[ 1,2-c][ 1,2,4]triazines synthesis, 3, 434 Indicated hydrogen nomenclature, 1, 33 Indigo, I, 317, 318-319, 4, 370 Baeyer synthesis, 1, 319 colour and constitution, 1, 344-345 molecular structure, 4, 162 photochromic compound, 1, 386 synthesis, 4, 247 Indigoid dyes... 

It should be stated that the nomenclature of the triazine derivatives is not uniform, e.g., in Chemical Abstracts the compounds are often indexed according to another sy.stem than that used in the original papers, and an additional system could have been used for this review. To avoid further complications, the author will u.se the commonest nomeclature in accordance with the representative monographs in this field (see references 12 and 45.)... 

In all types of nomenclature based on triazine the numbering of the substituents is shifted by one as compared with the nomenclature of 6-aza analogs of pyrimidines. 

The systematic nomenclature used originally the term imidazo-1,2,3-triazine. The Chemical Abstracts indexes use the more accurate name imidazo[4,5-d]-Z -triazine (141). The numbering of the substituents is different in the two systems of nomenclature as may be seen in the formulas. 

Dihydroxytriazinylformaldoxime, Dihydroxy-triazinylmethanol Oxime or 3,4-Dihydro-6-hydroxy-4-oxo-s-triazine-2-carboxaldehyde Oxime CA Nomenclature). 

The 1,3,5-triazines are amongst the oldest known organic molecules. Originally they were called the symmetric triazines, usually abbreviated to s- or sym- triazines. The numbering follows the usual convention of beginning at the heteroatom as shown for the parent compound 1,3,5-triazine (1). Rather non-systematic nomenclature is prevalent even in the current literature, because some of the compounds have been known for at least 150 years. The non-systematic names of some of the more important 1,3,5-triazines are listed in Table 1. The terms melamine, cyanuric acid and cyan uric chloride will be used throughout this chapter, and the term triazine will refer to 1,3,5-triazines only. In addition to the above names, 2,4,6-trialkoxy-l,3,5-triazines (2) are called cyanurates. Similarly, 1,3,5-trialkyl-1,3,5-triazines (3) are called isocyanurates. 

The nomenclature of several 1,3,5-triazines which were prepared in the early days of organic chemistry is clearly nonsystematic however, it has been used in the literature until the present day and is partially adopted in this section (Table 1). 

Thiatriazines arc not naturally occurring compounds. The nomenclature of 1,2,4,6-thia-triazines is based on the IUPAC rules and Chemical Abstracts.1 2 The valence state of the sulfur atom is assigned with the Greek letter lambda (/.). In this section, the chemistry of the ring system of 124,2,4,6-thiatriazines with three-coordinated sulfur and of the l/4,2,4,6-thiatriazine 1-oxides or 1-imides with four-coordinated sulfur with maximum unsaturation is described. A review of the literature until 1990 is available3 and also a more recent review.82... 

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