Thiolates triazine

Betaines 261 are stable crystalline compounds. Knowledge of their chemical reactions is still limited. Alkaline hydrolysis of aryl derivatives (261 R = Ar) gives the 2-azobenzoic acids 266 but the mechanism of this rearrangement is unknown. Reduction by tin and hydrochloric acid gives the hydrazides 267. Thermolysis of the p-tolyl compound (261 R = p-MeC6H4) (120 C at 0.1 mm Hg) gives the isomeric triazine (268 R = >-MeC6H4). Phosphorus pentasulfide converts the 2-methyl derivative (261 R = Me) into 2-methyl l,2,3-benzotriazinium-4-thiolate (272 R = Me) (Section in,B,15). 

The dye C.I. Solubilised Sulphur Red 11 [90218-69-2] (25) contains neither thiolate groups nor their precursors. It is prepared by treating perylenetetracarboxylic dianhydride with l,4-diaminobenzene-2-sulfonic acid, then with cyanuric chloride and with NH3. It is not known whether the chlorine of the monochloro-triazine groups of the precursor is replaced by a mercapto group in dyeing. 

Of the many other methods we can mention the preparation of biospecific adsorbents utilizing trichloro-5-triazine [120], coupling via thiol-disulfide interchange with activated thiolated support [121] or via azide formation [122]. The attachment of affinants containing the aromatic residues can be carried out by means of diazonium groups [87,123]. The coupling of the affinant onto the silinized glass after the reactions with p-nitrobenzoylchloride followed by reduction with sodium dithionite was described by Weetall and Filbert [124]. 

Additional Foolproof Synthetic Reactions Are Needed Professor Whitesides opened this subject by a challenge to the audience very few known synthetic reactions actually work I.e., work reliably in a foolproof fashion, in high yield, and in a way that is immune to variation in the structure of the substrates. One of the very few sequences for the coupling of molecules into larger entities that he has found to be fairly reliable is the formation of a chloroacetamide followed by a coupling with a thiolate. It is also possible to react trichloro-l,3,S-triazine with an amine quite reliably. Why are there so few other reactions that are really dependable ... 

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