Methane, tris synthesis

The tri(azulenyl)methane derivative 24+ including a 6-azulenyl group was prepared by the reaction of azulene 6b with diethyl 6-formylazulene-l,3-dicarboxylate. Synthesis of 24+ was accomplished by hydride abstraction with DDQ. Cation 24+ was isolated as a hexafluorophosphate salt by treatment with aqueous HPF6. The new salt is a stable, deep-green colored crystals, that can be... 

The synthesis of tripyrazolylmethane and similar reactions of N-magnesium bromide derivatives of pyrazoles (see below) show that the reactive center cannot be transferred from nitrogen to the a-position of the ring as with pyrrole.719-722 Unlike the CH-group of triphenyl-methane, that in tri-l-pyrazolylmethane is not labile.719 The 1-pyrazolyl group is presumably a weaker electron acceptor than a phenyl group because the electron pair of the 1-nitrogen atom is not completely withdrawn into the aromatic system. 

We are going to do a little more than simply give the reactions that eventually made up the synthesis of dofetilide. We are going to put ourselves in the place of the chemists who invented the synthesis and try to see what led them to the reactions they chose. First, we should inspect the structure of the molecule. There are two sulfonamides, one at each end. We have seen how to make sulfonamides earlier in this chapter when saccharin was being discussed. The usual way is to react the amine with a sulfonyl chloride. In this case we shall need to react methane sulfonyl chloride (MeS02Cl or MsCl) with the aromatic amines. This is a well-known reaction and should work well here. The other functional groups—tertiary amine and alkyl aryl ether—should not interfere so no protection is needed. 

Promoters are normally incorporated in quantities less than 1%. Zinc is known as one of the most effective promoters for the direct synthesis methylchlorosilanes.33 Cadmium is known as one of the most effective promoters for the direct synthesis of tris(sila)alkanes,20 bis(chlorosilyl)methanes,22 and tris(chlorosilyl)methane.23 In the direct reaction of (dichloromethyl)silane 6b, the total amounts (percentages) of (trisilyl)methane.23 In the direct reaction of (dichloromethyl)silane 6b, the total amounts (percentages) of (trisilyl)methane products 7b-10b in the... 

Synthesis of Tris[l,14-tri(dimethylsilyl)hexyl-dimethylsilyl]Methane... 

The reactivity of cellulose toward tri(p-toluenesulfonyl)methane chloride was recently examined [89]. The tosyl reagent is more reactive than trityl chloride, and the primary hydroxyl position exhibited 43 times more reactivity than the secondary hydroxyl groups. The products were used as intermediates in the synthesis of selectively modified cellulose derivatives [89]. As mentioned earlier, a high DS, organosol trimethylsilylcellulose has been prepared in DMAc/LiCl [10]. The condensation of polysaccharides with triphenyl-methyl (trityl) chloride proceeds generally with preference for the primary hydroxyl positions. The tritylation of cellulose occurs initially 58 times faster at the hydroxyl group at C6 than at either C2 or C3 [90]. 

Robinson, M.R., O Regan, M.B., and Bazan, GC. (2000) Synthesis, morphology and optoelectronic properties of tris[(W-ethylcarbazolyl)(3, 5 -hexyloxybenzoyl)-methane](phenanthroline)europium. Chemical Communications, 1645-1646. 

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