Preparation of a new receptor for anions, macrocyclic polythiolactam—structure and high anion-binding ability

Synthesis of 1,2,3,9a-tetrahydro-9H-imidazo[1,2-a]indole-2-thione and 1,5,6,10b-Tetrahydroimidazo[2,1-a]-isoquinoline-2(3H)-thione derivatives

“…The C-3 and C-9a chemical shift values for compound 2a were found at δ 66.90 and 98.86 ppm, respectively, while the corresponding values in starting compound 1a were found at δ 55.21 and 91.25 ppm. Similar low-field shift effects were observed when C=O groups of polylactams were converted to C=S groups [4]. In our previous work, it was found that alkylation of imidazo[1,2-a]indol-2-one derivative 1a by alkyl iodides in aprotic polar solvent in the presence of a strong base afforded a mixture of N-and O-alkylated products, in a ratio ~5:1 [8].…”

“…

Thionation of heterocyclic compounds bearing lactam moieties is most commonly performed using phosphorus pentasulfide [1,2] or 2,4-bis(4-methoxyphenyl)-1,3-dithia-2,4-diphosphetane-2,4-disulfide (Lawessons's reagent) [3,4]. The latter reagent usually gives the expected thiolactams, while heating of the lactam moiety containing heterocycles, e.g., 2,3,4,5-tetrahydro-1,5-benzodiazepin-2-one derivative, with phosphorus pentasulfide in pyridine affords a mixture of tautomeric thiolactam and imino thiol [2].

In the present work we investigated the replacement of carbonyl oxygen of five-membered lactam-type rings annelated to the a-edge of indole or isoquinoline nucleus by the use of Lawessons's reagent as a thionation agent.

Starting imidazo[1,2-a]indol-2-one derivatives 1a,b were obtained from 2,3,3-trimethyl-and 2,3,3,5-tetramethyl-3H-indoles by the method described in [5].

…”

“…Thionation of heterocyclic compounds bearing lactam moieties is most commonly performed using phosphorus pentasulfide [1,2] or 2,4-bis(4-methoxyphenyl)-1,3-dithia-2,4-diphosphetane-2,4-disulfide (Lawessons's reagent) [3,4]. The latter reagent usually gives the expected thiolactams, while heating of the lactam moiety containing heterocycles, e.g., 2,3,4,5-tetrahydro-1,5-benzodiazepin-2-one derivative, with phosphorus pentasulfide in pyridine affords a mixture of tautomeric thiolactam and imino thiol [2].…”

Secondary Thioamides as Multidentate Ligands for Functional Metal Complexes

“…In addition, our research group investigated anion-and neutral-molecular receptors using sec-TA-based macrocyclic molecules. 49,50 These studies showed that anion and molecular recognition can be achieved by exploiting the hydrogen bonding between the sec-TA-based molecule and a hydrogen-bond acceptor such as the anion or amides. Jurczak's research group also studied the anionrecognition properties of sec-TAs compared to those of their amide analogues.…”

Synthesis and recognition properties of colorimetric anion chemosensor bearing 2,4-dinitrophenylhydrazone and indene-1,3-dione moieties

“…In recent years, the development of chemosensors capable of selectively recognizing and sensing anions appears to be particularly attractive [2][3][4][5][6][7]. There is an increasing attention toward the development of colorimetric probes which have the advantage of showing easily observable color changes in the presence of target guests.…”