Tetraalkylated 2,8,14,20-tetrathiacalix[4]arenes: Novel infinite channels in the solid state

Chemistry of Thiacalixarenes

“…Hence, this method is suitable for large-scale (multi-gram) preparation of the 1,3-alternate conformers 16d and 17d, which can be obtained in high yields (about 60 %) by simple precipitation 1678 from the crude reaction mixture with CHCl 3 /methanol. [15] Surprisingly, using Method B, 2 did not give the expected cone conformer 16a. After two days, almost one half of the starting material remained unchanged and only small amounts of 16b, 16c, and 16d were isolated from the reaction mixture.…”

“…For example, the parent thiacalix [4]arene (1, n ϭ 4, R ϭ H) has the somewhat cumbersome name 2,8,14,20-tetrathiapentacyclo[19.3.1.1 3,7 .1 9,13 .1 15,19 ]-octacosa-1(25),3,5,7(28),9,11,13 (27), 15,17,19(26),21,23-dodecaene-25,26,27,28-tetrol. Therefore, not surprisingly, the well-established nomenclature, numbering, and rules for ''classical'' calixarenes [1] have also been accepted for the thiacalixarene family.…”

Thiacalix[4]arenes with Triple Bonds at the Lower Rim: Synthesis and Structure

“…This result, not entirely unexpected, may be explained by the observation that the same reactions with alkyl iodide/bromide gave less than 2 % yields of alkylation products. [16] At the same time the more reactive allyl bromide (compared to alkyl bromides) in acetonitrile offered the compound 5 in 1,3-alternate conformation with 44 % yield. [32] Theoretically, propargyl bromide should be even more reactive than allyl bromide.…”

“…[2,15] Accordingly, several groups have investigated [15,[16][17][18] the functionalization of (thia)calixarenes 1-4 by alkyl halides using the acetone(acetonitrile)/M 2 CO 3 reaction system (M ≡ Na, K, and Cs). As a part of our research into the derivatization of lower rim of these macrocycles, [3,[19][20][21][22][23][24][25][26][27][28][29][30][31] a systematic study of the reaction of thiacalix [4]arene 3 and p-tert-butylthiacalix [4]arene 4 with propargyl bromide in the presence of alkali metal carbonates (Scheme 1) was carried out.…”

“…[16] Despite the fact that the preparative synthesis leads to 1,3-alternate conformer, most thermodynamically stable isomer is partial cone that indicates on the kinetic control in the above reactions.…”