3-pyridyl group

The iminophosphoranes of methyl arylhydrazono acetates (338) possessing a keto function in an o-position afford l//-l,2,4-benzotriazepines (339) upon heating (Scheme 123). The yield depends on the substituents and solvents employed. Methoxycarbonyl-, 4-pyridyl-, and 3-pyridyl groups activate the carbonyl function and improve the yield. Reactions of alkyl ketones and aldehydes proved to be unsuccessful [91JCR(S)2],... 

The lead compound for SB 204741 was the [3-(trifluoromethyl)phenyl] urea analogue, having a 100-fold greater potency for the 5-HT receptors in rat stomach fundus than in rat jugular preparations [45] (Table 17, compound 1). Replacement of the trifluoromethylphenyl moiety by a 3-pyridyl group and removal of the alkyl substituents at the 2- and 3-positions of the indole nucleus increases the affinity of the rat stomach fundus receptors 2-fold (Table 17, SB 200646). 

Shelnutt et al. have reported the formation of nanotubes by co-assembly of positively and negatively charged porphyrin derivatives [21]. When porphyrins 5 (Fig. 5a) and 6a (Fig. 5b), appended with sulfonate and 4-pyridyl groups, respectively, are allowed to co-assemble in water, nanotubes with 50-70 nm in diameter and approximately 20 nm in wall thickness are yielded, as observed by TEM microscopy (Fig. 5c). The use of 6b having 3-pyridyl groups, instead of 6a, for the co-assembly with 5 leads to the formation of nanotubes with a smaller diameter (35 nm) and a larger wall thickness. On the other hand, no tubular object results when 6c with 2-pyridyl groups is used for the co-assembly. It is noteworthy that the central metal ion of the pyridylporphyrin affects the nanotube formation. While similar nanotubes form when Sn " " in 6a is replaced with other six-coordinate metal ions such as Fe, Co, TiO, and the use of... 

Along these lines about 200-250 compoimds were prepared. Included in this number are examples which contain a 2-pyrazinyl or a 5-pyrimidyl group instead of the 3-pyridyl group. The two biologically most interesting compounds at that stage of work were definitely the oxime ether 12 and the ketal 14. Both were chosen for extended field evaluation. 

In 50 per cent aqueous acetone at 30°, the ratios of hydrolysis rates ll for />-nitrobenzenesulphonyl, m-nitrobenzenesulphonyl, pyridine-3-sulphonyl and benzenesulphonyl chloride are 5T5 2-52 2-28 1, whilst in aqueous dioxan the 3-pyridyl group was found to be more activating than either m- or / -nitrophenyl . 

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