Triazine hydroxy derivatives

SnCl2 reduction produced the 4-hydrazinoisoxazole (243). In ethanol the diazonium salt reacted with the 4-aminoisoxazole to produce the linear triazine (244) (Scheme 85). Diazoisoxazoles can also be treated with KI or H20/urea to produce the 4-iodo or 4-hydroxy derivatives (63AHC(2)365). These Sandmeyer reactions have been extended to a variety of isoxazole systems (77JMC934, 63AHC(2)365). 

Direct bromination readily yields the 6-bromo derivative (111), just as with uracil. Analogous chlorination and iodination requires the presence of alkalies and even then proceeds in low yield. The 6-chloro derivative (113) was also obtained by partial hydrolysis of the postulated 3,5,6-trichloro-l,2,4-triazine (e.g.. Section II,B,6). The 6-bromo derivative (5-bromo-6-azauracil) served as the starting substance for several other derivatives. It was converted to the amino derivative (114) by ammonium acetate which, by means of sodium nitrite in hydrochloric acid, yielded a mixture of 6-chloro and 6-hydroxy derivatives. A modified Schiemann reaction was not suitable for preparing the 6-fluoro derivative. The 6-hydroxy derivative (115) (an isomer of cyanuric acid and the most acidic substance of this group, pKa — 2.95) was more conveniently prepared by alkaline hydrolysis of the 6-amino derivative. Further the bromo derivative was reacted with ethanolamine to prepare the 6-(2-hydroxyethyl) derivative however, this could not be converted to the corresponding 2-chloroethyl derivative. Similarly, the dimethylamino, morpholino, and hydrazino derivatives were prepared from the 6-bromo com-pound. ... 

When it was found later that enzymatic oxidation of 2-azaadenine yields its 8-hydroxy derivative (4-amino-6-hydroxyimidazo [4,5-d]-u-triazine), its synthesis was also achieved by the procedure already described/ ... 

Reaction of the triazine 1-oxides (54a,b) with HN02 gave the corresponding 3-hydroxy derivatives (204a,b) in 88% and 78% yield, respectively. Subsequent treatment of compounds (204a,b) with hot... 

Silylation and alkylation are other methods of modifying triazines. An HMDS—TMCS mixture was used for the preparation of TMS derivatives [492]. Flint and Aue [493], who evaluated several reagents, recommended performing silylation with the aid of BSTFA by heating at 150°C for 15 min. Under these conditions, hydroxy derivatives of simazine, atrazine and propazine provided one large peak and few by-products, identified as mono-, di- and trisilyl derivatives 10% of OV-17 was used as the stationary phase. 

Due to lack of adequate TLC visualization, secondary confirmation of some metabolites by TLC comparison with synthetic reference standards was not possible. Chemical conversion of a number of thiomethyl triazines to their respective hydroxy-derivatives was carried out in order to obtain more easily visualized products. After 6 N HCl hydrolysis, ametryn was converted exclusively to 6-hydroxy-atrazine (CG-7). 

Remarkable in the metabolism shown in the scheme is that, while 2-chloro-4,6-bis(alkylamino)->triazines in plants and soil are converted first to the hydroxy derivative, the decomposition does not yield the hydroxy derivative until the third... 

Muller and Payot (196S) established by the radioactive-isotope method that the methylthio group of bis(alkylamino)-2-methylthio-. -triazines is oxidised in plants first to the sulfoxy then to the sulfon group, which is then quickly hydrolysed to the inactive hydroxy derivative ... 

The aromatic nature of 1,2,3-triazines is suggested by various spectral data, which are given in Section 6.10.2. In terms of tautomerism, there is little information concerning the monocyclic series. 5-Hydroxy derivatives have been isolated and appear to exist in the 0x0 forms (see Section 6.10.6). Benzotriazin-4-one ( 4-hydroxybenzotriazine ) has long been known to exist in the 3H form, and its 1- and 2-oxides are likewise 3H structures. The pK values have been determined for all of these compounds, and for 3-hydroxybenzotriazin-4-one <89JCS(P1)543>. 

HPLC is directly applicable to 1,3,5-triazines and their degradation products. Hydroxy derivatives have been separated in RP systems with acidic and weakly alkaline mobile phases. The chromatographic behavior of 18 1,3,5-triazines has been studied in a RP system with a separon SLC 18 stationary phase and a mobile phase of aqueous sodium dihydrogen phosphate and methanol... 

The lateral-nuclear rearrangement of aryloxy-l,3,5-triazines had previously received the attention of Shizuka and co-workers.194 The same research school now reports the effect of irradiation on a large number of aryloxy-sym-triazines (160).195 In general o- and/or p-hydroxy-derivatives of aryl-sym-triazines (161)... 

For the synthesis of this ring system, two routes have mainly been employed. Mono- or bicyclic 1,2-diaminopyridinium salts were reacted with 1,2-dicarbonyl compounds or AT-aminopyridinium salts were treated with various azirines. 1,2-Diaminopyridinium salts (140) with arylglyoxals gave 2-arylpyrido[l,2-h][l,2,4]triazines (141), whereas 3-aryl-2-hydroxy derivatives (142) were formed under neutral conditions (Scheme 10). The latter compounds could then be dehydrated <70KGSl 148, 73KGS1266, 92T8459). 

In the past decade, a shift of emphasis in 1,2,3-triazine chemistry is to be noted from preparative to theoretical work. Interest in theoretical predictions of molecular properties of the parent 1 was evident from the literature over the past 40 years and has increased recently. On the other hand, benzotriazinones of type 3 receive attention primarily for the biological activity of many derivatives, and the 3-hydroxy derivative serves as a basis for active esters as coupling reagents in peptide synthesis. Via ring-chain tautomerism, 4-hydroxy-3,4-dihydrobenzotriazines derived from 12 are opened to triazenes which show cytotoxicity. 

UV absorbers have been found to be quite effective for stabilization of polymers and are very much in demand. They function by the absorption and harmless dissipation of the sunlight or UV-rich artificial radiation, which would have otherwise initiated degradation of a polymer material. Meyer and Geurhart reported, for the first time in 1945 [10], the use of UV absorber in a polymer. They found that the outdoor life of cellulose acetate film was greatly prolonged by adding phenyl salicylate (salol) [10]. After that, resorcinol monobenzoate, a much more effective absorber, was introduced in 1951 [11] for stabilization of PP, but salol continued to be the only important commercial stabilizer for several years. The 2,4-dihydroxybenzophenone was marketed in 1953, followed shortly by 2-hydroxy-4-methoxybenzophenone and other derivatives. Of the more commonly known UV absorbers, the 2-hydroxybenzophenones, 2-hy-droxy-phenyl-triazines, derivatives of phenol salicylates, its metal chelates, and hindered amine light stabilizers (HALS) are widely used in the polymer industry. 

A. T. Au. Acyl derivatives of tniy-hydroxy-ethyl-perhydro-1,3,5-triazine. Patent US 4605737, 1986. 

DAST-type FBAs may contain by-products (such as 11.13) derived from hydrolysis of one or more of the chloro substituents in cyanuric chloride (11.10). One such troublesome byproduct is 2,4-bis(anilino)-6-hydroxy-s-triazine (11.62). Not only is this compound environmentally undesirable, it may also interact with certain bleaching agents and its presence can lead to the development of unpleasant odours on storage of a detergent... 

Amino-4,5-dihydro-5-hydroxy-l,2,4-triazine (82B) exhibits a temperature-dependent equilibrium with the open-chain hydrazide-hydrazone derivative 82A in CDCI3 solution, as shown by the H-NMR data (85LA78). 

Various extensions are possible (see CHEC 2.19 for full details). Use of aminoguanidines, semicarbazide and thiosemicarbazide gives respectively the 3-amino-1,2,4-triazine, and the 3-one and 3-thione derivatives. Use of a-keto esters and a-keto cyanides gives 5-ones and 5-amino derivatives, respectively. a-Hydroxy ketones afford dihydro-1,2,4-triazines. Intermediates (479) and (480) can sometimes be isolated. 

In a similar way, l,2,4-triazin-5-ones (31) were found to exist in solution predominantly in the 2//-form, but in the solid state the 5-hydroxy tautomers (32) predominate, at least in the 3-phenyl and 6-phenyl derivatives (78HC(33)189, p. 250,74T3171). 

Amino-l,2,4-triazin-5-ones (674) have been prepared by the reaction of a-acyl-hydrazonocarboxylates (672) or the chloro derivatives (673) with hydrazine. The chloroazines (673) with hydroxylamine afford 4-hydroxy-1,2,4-triazin-5-ones (675 Scheme 26) <78HC(33)189, p. 563). 

With the l,3,5-triazin-2-yl derivatives of 4,4 -diaminostilbene-2,2 -disulfonic acid proposed by B. Wendt in 1940 [25], optical brighteners came into full-scale industrial use. In 1941, 4,4 -bis (4-anilino-6-hydroxy-l,3,5-triazin-2-yl)aminoJstil-bene-2,2 -disulfonic acid disodium salt was introduced commercially under the trade name Blankophor B (3) [1264-32-0],... 

Nitrogen-containing heterocycles are of obvious interest in the context of prebiotic chemistry. This is the reason why we will now consider this class of derivatives. The first so-called evidence for the presence of 4-hydroxypyrimidine and 4-hydroxy-methyl-pyrimidine in Murchison was published in 197158These results were divergent from those of previous studies performed on Orgueil samples where adenine, guanine, j-triazines and guanylurea were detected 59 60). 

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