SHORT COMMUNICATIONSDialkylaminomethyl-substituted calix[4]resorcinarenes have been reported long ago [1], but further transformations of these compounds were reported in a few publications [2][3][4], and the described transformations did not involve the dialkylaminomethyl group therein. An exception was the formation of the corresponding ammonium salts [5, 6] and thioamides [7]. Products of nucleophilic replacement of dialkylamino group in the above calix[4]resorcinarenes were not reported. On the other hand, deamination of phenolic Mannich bases is their typical reaction [8].Deamination of freshly prepared dialkylaminomethyl-substituted calix[4]resorcinarenes Ia and Ib by the action of 2,6-di-tert-butyl-4-sulfanylphenol (II) resulted in the formation of previously unknown calixarene III containing sterically hindered phenylsulfanyl fragments (yield 68-72%). We also found that the duration of storage of initial compound Ib does not affect the yield of III. By contrast, the reaction of benzenethiol II with calixarene Ia preliminarily stored for 3 months gave a mixture of products of partial replacement of the dimethylamino groups (according to the 1 H NMR data) even after heating for 66 h. The reactivity of calix[4]resorcinarene Ia can be restored after prolonged storage by washing with dimethyl sulfoxide and then with water, followed by drying in air. Presumably, the reactivity of aminomethyl calixarene derivatives Ia and Ib depends on their supramolecular organization.According to [9], molecules of calix[4]resorcinarene Ia in crystal are linked to dimers where dimethylaminomethyl groups of neighboring molecules enter the macroring cavity in each other; therefore, these groups become spatially inaccessible for nucleophilic attack. Such associates are likely to dissociate by the action of solvent, whereas prolonged drying favors the R = Me (a), Et (b).