Tadayo Miyasaka

Monitored aminolysis of 3-acylthiazolidine-2-thione : A new convenient synthesis of amide

Abstract 3-Acylthiazolidine-2-thiones ( 1 ) were easily prepared and they were treated with several amines in dichloromethane to give amides 4 in very high yields within a short time. Aminoalcohols and aminophenols were selectively converted into acylaminoalcohols and acylaminophenols, respectively, by this reaction. One can monitor the reaction by disappearance of the yellow color of the starting material 1 . Some amide alkaloids ( 1 5 – 1 8 ) have effectively been synthesized.

Total synthesis of the macrocyclic spermidine alkaloids (±)-lunarine and (±)-lunaridine

Total syntheses of (±)-lunarine (1) and (±)-lunaridine (2) have been performed via aminolysis of the thiazolidine-2-thione diamide derivative (10) with spermidine (11).

Synthesis of parabactin analogues and formation of transition metal complexes of parabactin and related compounds

Transition metal complexes of parabactin and its related synthetic spermidine catecholamides which lack the central o-hydroxyphenyloxazoline were studied by the potentiometric titration method, e.s.r. spectroscopy, and fast atom bombardment mass spectrometry (FAB-MS). Direct mass spectral sampling of the parabactin–FeIII complex in glycerol solution was first achieved by FAB-MS spectrometry, confirming that the composition of the parabactin–FeIII complex is [Fe(parabactin)]2– 2Na+ and that the iron(III) ion binds with two catechols and an o-hydroxyphenyl-Δ2-oxazoline moiety in NaOH solution. The e.s.r. g value (4.5) of the parabactin–FeIII complex differed from those (4.3) of the 3 : 1 catechol–FeIII complex and other parabactin-related catecholamide–FeIII complexes. These results suggest that the structure of the parabactin–FeIII complex differs considerably from the regular octahedral structure of the 3 : 1 catechol–FeIII complex and may have a structure similar to the ferrimycobactin P–FeIII complex, in which the iron(III) ion lies exposed in a splayed V-shaped cleft and binds with five oxygens and one nitrogen in a very strained octahedron.

Studies on the structure of some derivatives of 1,3-thiazolidine-2-thione and Δ2-1,3-thiazoline-2-thiol

Two types of reactions have been observed for the ambident anion of 1,3-thiazolidine-2-thione: regioselective N-acylation and S-alkylation. The structures of the products, amides and thioethers, were determined by X-ray crystallographic analysis and by assignment of the 13C n.m.r. chemical shifts. The regioselectivity of the reactions is rationalised in terms of the hard–soft acid-base principle and has been exemplified by model experiments.

Synthesis of novel streptonigrin 2-amide derivatives with 3,3′-(phenylphosphoryl)bis(1,3-thiazolidine-2-thione)

Novel streptonigrin 2-amide derivatives have been efficiently synthesized without protection by using 3,3′-(phenylphosphoryl)bis(1,3-thiazolidine-2-thione)(PPBTT) as a chemoselective condensing agent.

Peptide-bond formation, chemoselective acylation of amino acids, and crosslinking reaction between amino acids utilizing a functional five-membered heterocycle, 1,3-thiazolidine-2-thione

The monitored aminolysis of 3-acyl-1,3-thiazolidine-2-thiones has been extended to the peptide-bond formation, the chemoselective acylation of amino acids having multifunctional groups, and the crosslinking reaction between amino acids.

Total synthesis of parabactin, a spermidine siderophore

The sterereoselective total synthesis of parabactin (1) has been efficiently carried out using substituted 1,3-thiazolidine-2-thione as a leaving group.