Cyanuric chloride, formation

Cyanoguanidine, 3 43 Cyanuric chloride, formation of, from cyanogen chloride, 2 94 1-Cyclohexyl-l, 1-diethylhydra-zonium chloride, 6 92 Cyclopentadiene, magnesium and other metal derivatives of, 6 11, 15... 

Cyanuric acid, chlorination, 58, 324 Cyanuric chloride, formation, use, 58,... 

Even polyalkoxy-s-triazines are quite prone to nucleophilic substitution. For example, 2,4,6-trimethoxy-s-triazine (320) is rapidly hydrolyzed (20°, dilute aqueous alkali) to the anion of 4,6-dimethoxy-s-triazin-2(l )-one (331). This reaction is undoubtedly an /S jvr-4r2 reaction and not an aliphatic dealkylation. The latter type occurs with anilines at much higher temperatures (150-200°) and with chloride ion in the reaction of non-basified alcohols with cyanuric chloride at reflux temperatures. The reported dealkylation with methoxide has been shown to be hydrolysis by traces of water present. Several analogous dealkylations by alkoxide ion, reported without evidence for the formation of the dialkyl ether, are all associated with the high reactivity of the alkoxy compounds which ai e, in fact, hydrolyzed by usually tolerable traces of water. Brown ... 

In the preparation of other DAST brighteners it may be advantageous to avoid reacting DAS with cyanuric chloride in the first step. It is difficult to suppress the reactivity of the second chloro substituent completely and undesirable by-products of the general type 11.11 can be eliminated if DAS is made to react with a dichlorotriazine intermediate in the second step. Very careful control of the reaction conditions, especially in steps 1 and 2, is also necessary in order to avoid formation of partially hydrolysed by-products such as structures 11.12 and 11.13. 

Of the factors associated with the high reactivity of cyanuric chloride (high exother-micity, rapid hydrolysis in presence of water-containing solvents, acid catalysed reactions, liberation of up to 3 mol hydrogen chloride/mol of chloride, formation of methyl chloride gas with methanol, formation of carbon dioxide from bicarbonates), several were involved in many of the incidents recorded [1] (and given below). The acid catalysed self acceleration and high exothermicity are rated highest [2]. It is also a mildly endothermic compound (AH°f (s) +91.6 kJ/mol, 0.49 kJ/g). 

Cyanuric chloride reacts vigorously and exothermically with DMF after a deceptively long induction period. The 1 1 adduct initially formed decomposes above 60° C with evolution of carbon dioxide and formation of a dimeric unsaturated quaternary ammonium salt. Dimethylformamide is appreciably basic and is not a suitable solvent for acyl halides. 

Superoxide dismutase PEG (1900, 4000, 5000) 95%, cyanuric chloride 95%, carbonyldiimidazole 40% phenylchloro-formate Phase III 80-82... 

Recently, it has been shown that acyl chlorides may be prepared from cyanuric chloride and carboxylic acids (79TL3037). Cyanuric chloride is also valuable for effecting the formation of macrocyclic lactones (Scheme 44) (80TL1893). Similarly, aryl oximes may be converted to... 

In general, the chemistry of fluoro-l,3,5-triazines resembles that of the chloro derivatives, and therefore will not be discussed in detail. There is evidence that cyanuric fluoride is less reactive than cyanuric chloride in reaction with aniline (76CCC3378). Chambers et al. have reported the isolation of a stable anion cr- complex from the reaction of cyanuric fluoride and cesium fluoride (equation 32) (77JCS(Pl)l605). Such species are believed to be intermediates in the formation of (68) from cyanuric fluoride and perfluoropropene (equation 33). Olah et al. have shown that cyanuric fluoride deoxygenates sulfoxides efficiently (equation 34) (80S221). 

Cyanuric chloride reciystallization. Cyanuric chloride (30 g, 0.16 mol) is dissolved in hot petroleum ether (500 mL) with constant stirring in an oil bath. Heated petroleum ether is poured over a fluted filter paper and the solution of cyanuric chloride filtered into a 1-L conical flask. The saturated solution of cyanuric chloride is left overnight, covered, to allow formation of crystals. The crystals are filtered and dried under reduced pressure. The dried crystals are stable at room temperature in an airtight container. The yield is about 95%. 

C = condensation, OC = oxidative coupling, PF = phenol formaldehyde, NA = crosslinking not performed-modification was aimed at network formation, BD = bis-diazonium salts, AAC = aryl acid chlorides, CC = cyanuric chloride, NEH = normal epoxy hardeners, MEA = methacrylate. 

Amide substituents on the thioureas, upon desulfurization, give rise to the formation of carbamoylcarbodiimides 8. In this reaction cyanuric chloride in the presence of triethy-lamine is used to affect the desulfurization. For example, when R=C6Hn and R =t-Bu, the corresponding carbamoylcarbodiimide, mp 119 °C, is obtained in 82 % yield. 

Cyanuric chloride, rather than the fluoride, is used for the formation of polyfluoroalkoxy derivatives [145] the probable advantage of using the perchloro compound lies in reducing the possibility of a back-reaction when X = Cl in the sequence shown in Figure 9.58. 

Natural polymer-based networks have also been investigated. The proteins etc comprising antibodies represent the largest group [164, 166, 169, 189] but this is of course a specialised area. Poly(saccharides), in particular starch [60], dextran [161], dextrin [161] and maltohexose [161], and also natural polypeptides, mainly enzymes [162-165], embody the more accessible biopolymers. In some instances imprinting is achieved through formation of covalent bonds, with crosslinkers like cyanuric chloride or glutaraldehyde. Likewise chitin derivatives similarly crosslinked have been exploited [136]. 

Cyanuric chloride has been used for the preparation of acyl chlorides, amides, and peptides. Conversion of cyanuric chloride into 2-chloro-4,6-dimethoxy-l,3,5-triazine (CDMT, 6) leads to a reagent that upon reaction with carboxylic acids produces the highly reactive 2-acyloxy-4,6-dimethoxy-l,3,5-triazines.P l The resulting active ester is a powerful acylating agent for alcohols and amines. The activation is performed in presence of a base, preferentially NMM, which leads to intermediate formation of 4-(4,6-dimethoxy-l,3,5-triazin-2-yl)-4-methylmorpholinium chloride (DMTMM, 7)P l (Scheme 5). This addition product is readily prepared from the commercially available CDMT (6) and NMM in THF and can be stored as solid compound in the cold.P P l It offers the advantage that it can be used in a one-... 

Cyanuric fluoride, cyanuric bromide and particularly cyanuric chloride are the most important starting materials for the formation of a large number of 2,4,6-trisubstituted 1,3,5-triazines (cf. Houben-Weyl. Vol. 5/3, p 417. 

Alkylsulfanyl groups in 1,3,5-triazines are replaced by a chlorine substituent when treated with gaseous chlorine, e.g. as shown in the formation of cyanuric chloride 3. 

For the preparation of the symmetrically substituted 2-chloro-4,6-bis(alkyl-amino)-5-triazines, cyanuric chloride, suspended in the solvent-water mixture, is reacted with the amine in two temperature steps (0-5°C and 40-45°C) in the presence of inorganic acid acceptor (Pearlman and Banks, 1948 Thurston el ai, 1951 Gysin and Kniisli, 1959). Asymmetric 2-chloro-4,6-bis(alkylamino)-5-triazines (ametryne, sebuthylazine, terbuthylazine) can be synthesised in two reaction steps without the formation of symmetrical analogues. In the first step, the... 

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