Thiacalix[4] arenes with terminal thiol groups at the lower rim: synthesis and structure

Abstract

Methods were developed for the synthesis of ω mercaptoalkoxy derivatives of thiacalix [4] arenes in the 1,3 alternate conformation containing different numbers (2-5) of methylene spacers at the lower rim. The hydrazinolysis of the corresponding thioacetates is the most efficient method for the synthesis of these compounds.Natural and synthetic macrocyclic compounds show promise for studies in the field of supramolecular chemi stry, because the structural features of these compounds are favorable for a sharp enhancement of the complex ation properties due to the formation of multicenter intermolecular interactions with substrates and the pre organization of coordination centers. Calixarenes 1 have additional advantages associated primarily with the unique possibilities of their functionalization and the fine tuning between the three dimensional structures of the host and the desired guest. The use of thiacalix[4]arene 2 (see Refs 1-5) as a molecular platform for the design of intel lectual receptor and self organized supramolecular sys tems is very attractive, because the replacement of the methylene bridges in the classical calixarene by sulfur atoms gives rise to new properties. 3,4,6-11 In this connec tion, it is important to develop approaches to the directed functionalization of this macrocycle, in particular, by introducing organosulfur fragments. The presence of func tional sulfur containing groups at the lower or upper rim of the macrocycle, in addition to four bridging sulfur atoms of the thiacalixarene platform, offers great possi bilities for the design of highly selective host molecules based on thiophilic metal ions, 12 the construction of highly organized nanolayers on the metal surface, 13-17 and the design of sensors based on ion selective electrodes. 18-20 In addition, these sulfur containing groups have a great synthetic potential for further modifications of the macro cyclic structure. * Dedicated to Academician A. I. Konovalov on his 75th birthday. Results and DiscussionIn the present study, we synthesized new O substi tuted thiacalix[4]arenes in the 1,3 alternate conformation containing ω bromo (3), ω acetoxy (4), or ω mercapto alkyl groups (5) linked by methylene spacers of different length (from two to five units). The structures of the new compounds were determined by different physical methods, such as 1D and 2D NMR spectroscopy, IR spectroscopy, and MALDI TOF mass spectrometry. The purity of the compounds was checked by TLC and elemental analysis.CH 2 H 2 S H 3a-e S (CH 2 ) n Br, n = 2 (a), 3 (b), 4 (c), 5 (d), 6 (e) 4a-d S (CH 2 ) n SC(O)CH 3 , n = 2 (a), 3 (b), 4 (c), 5 (d) 5a-d S (CH 2 ) n SH, n = 2 (a), 3 (b), 4 (c), 5 (d)

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

“…[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. Obtained data are summarized in the Table 1.…”

“…25,26,27,8,14, [4]arene, 3b-d. A mixture of thiacalix [4]arene 3 (1 g, 2 mmol), propargyl bromide (3.808 g, 0.032 mol), cesium/potassium carbonate (0.04 mol) was kept at boiling in acetone (100 ml) with continuous stirring for 50 hours. The reaction progress was monitored by TLC using a 1:2 hexane-toluene mixture as the eluent.…”

Synthesis and fluorescent properties of thiacalix[4]arenes containing terpyridyl fragments at the lower rim

“…35 Bromoalkoxy (2a-c) and mercaptoalkoxy sub stituted (4a,b) thiacalix [4]arenes were synthesized from 4 tert butylthiacalix [4]arene according to the known procedures, 36,37 respectively. 2 Microwave irradiation was performed in a CEM MARS Xtraction reactor in thick wall glass reactors at atmospheric pres sure; temperature was controlled using a built in fiber optic sensor.…”

Thiacalix[4]monocrowns Substituted by Sulfur-Containing Anchoring Groups: New Ligands for Gold Surface Modification

“…Thioaceto-substituted monocrowns 2a-f were obtained from bromo-substituted derivatives 1a-f [9] using the stoichiometric thiacalixarene-to-potassium thioacetate ratio of 1:2 (Scheme 2) with high yields (80-90 %) according to the method that was developed by us earlier for tetrasubstituted thiacalixarene derivatives. [20] Scheme 2.…”