Charge transfer complexes between I2 and 1,3-imidazolidine-2-thione and its n-mono- and n,n'-di-substituted derivatives

Spectrophotometric studies of iodine with 1,3-imidazolidine-2-thione and its N-mono- and N,N'-di-alkyl derivatives (alkyl = Me, Et) have been carried out in carbon tetrachloride and dichloromethane solutions. In each case, a new intense peak due to the charge transfer band of a 1:1 molecular complex was observed. The thermodynamic and spectral characteristics of these complexes have been determined. The well known “blue shift” of the visible band of I₂ is verified, but the analogous blue shift of the donor absorption is hidden by the solvents. To explain the very high differences between the stability constants of the N,N'-disubstituted derivatives and the others, an intramolecular H-bonding between NH and terminal iodine has been hypothesized. IR measurements carried out on N-ethyl-1,3-imidazolidine-2-thione seem to support this hypothesis.     

A Mild and Efficient Method for the Carbethoxylation of Amines

3-Carbethoxy-1,3-thiazolidine-2-thione [CTT(2)] has been prepared by treatment of 1,3-thiazolidine-2-thione (3) with ethyl chloroformate and triethylamine. CTT(2) shows high reactivity towards the amines.     

A Mild and Efficient Method for Selective Acetylation of Amines

Primary and secondary amines were acetylated under mild conditions by means of 3-acetyl-1,3-thiazolidine-2-thione [ATT(1)]. The reaction was successfully applied to selective acetylation of a primary amino group of diamines containing a primary and a secondary amino groups or exclusive N-acetylation of amino alcohols.     

An infrared spectroscopic investigation on N-methyl-1,3-thiazolidine-2-thione and -2-selone

An infrared investigation cm N-methyl-1,3-thiazolidine-2-thione and -2-selone in the range 4000-200 cm^?1 is reported. The v CS and v CSe vibrations give contributions to the absorptions around 1000 cm^?1 and below 600 cm^?1. The assignments are supported by comparison of their ir spectra with those of S- and Se-methiodides. The π-bond orders of the thio- and seleno-ketonic links in these compounds are higher than those found for 1,3-imidazolidine-2-thione and -2-selone.     

X-ray photoelectron spectra of Pd(II) and Pt(II) complexes with 1,3-thiazolidine-2-thione. A quantum mechanics study on the free ligand

Metal complexes of general formula M(ttz)2X2 (with M= Pd(II) or Pt(II); X = Cl or Br; ttz = 1,3-thiazolidine-2-thione) have been synthetized as crystalline compounds and studied by means of X-ray Photoelectron Spectroscopy (XPS). The chemical shift of core level signals showed that ttz is bonded to the metal through the thioketonic sulphur atom and that electronic charge redistribution in the ligand takes place after complexation. No metal-nitrogen bonds are present. This is consistent with the results of all the quantum mechanical models according to which hydrogen is bound to nitrogen, even in the hydrogen bonded complex, making the latter rather unavailable to coordination     

The first example of a copper(II) chloride complex with 1,3-thiazolidine-2-thione

Summary The reaction of copper(II) chloride with 1,3-thiazolidine-2-thione in absolute ethanol yields the complex CuL₂Cl₂. This derivative has been studied by elemental analyses, molar conductance, magnetic moment measurements at different temperatures, electronic and infrared spectroscopy, thermal analyses (TG and DTG) and e.p.r. techniques. The complex has a pseudooctahedral stereochemistry, with bridging halides and with the ligands monodentate-S-bondedvia the exocyclic sulphur atom.     

Reaktion von 3-(Dimethylamino)-2H-azirinen mit 1,3-Thiazolidin-2-thion

Reaction of 3-(Dimethylamino)-2H-azirines with 1,3-Thiazolidine-2-thione Reaction of 3-(dimethylamino)-2H-azirines 1 and 1,3-thiazolidine-2-thione ( 6 ) in MeCN at room temperature leads to a mixture of perhydroimidazo[4,3-b]thiazole-5-thiones 7 and N-[1-(4,5-dihydro-1,3-thiazol-2-yl)alkyl]-N′,N′-dimethylthioureas 8 (Scheme 2), whereas, in i-PrOH at ca. 60°, 8 is the only product (Scheme 4). It has been shown that, in polar solvents or under Me₂NH catalysis, the primarily formed 7 isomerizes to 8 (Scheme 4). The hydrolysis of 7 and 8 leads to the same 2-thiohydantoine 9 (Scheme 3 and 5). The structure of 7a, 8c , and 9b has been established by X-ray crystallography (Chapt. 4). Reaction mechanisms for the formation and the hydrolysis of 7 and 8 are suggested.     

Total synthesis of mycothiazole, a polyketide heterocycle from marine sponges

Mycothiazole isolated from marine sponges has been efficiently synthesized in a convergent manner. The key reactions involve the thiazole synthesis by dehydrogenation of the thiazolidine with chemical manganese dioxide (CMD), the Stille coupling, and the Nagao asymmetric acetate aldol reaction using the chiral 1,3-thiazolidine-2-thione. This synthesis clearly established the absolute configuration of natural mycothiazole to be (R).     

Reaction of 1,3-thiazolidine-4-carboxylic and 1,4-tetrahydro-thiazine-3-carboxylic acid esters with isocyanates and isothiocyanates and structures of the reaction products

7-Thia-1,3-diazabicyclo[3.3.0]octane-2,4-diones and 7-thia-1,3-diazabicyclo[4.3.0]-nonane-2, 4-diones, as well as their thio analogs, were obtained by the reaction of (S)-1,3-thiazolidine-4-carboxylic and 1,4-tetrahydrothiazine-3-carboxylic acid esters with isocyanates and isothiocyanates. Intermediate reaction products, viz., heterocyclic derivatives of urea, were isolated. The three-dimensional structures of the 3-methyl-4-oxo-7-thia-1,3-diazabicyclo[3.3.0]octane-2-thione and 3-methyl-4-oxo-7-thia-1, 3-diazabicyclo[4.3.0]nonane-2-thione molecules were determined by x-ray diffraction analysis.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1327–1332, October, 1985.     

Copper(I) complexes from copper(II) halides and 1,3-thiazohdine-2-thione

Summary Reaction of 1,3-thiazolidine-2-thione and copper(II) chloride and bromide in MeOH yields CuL₃X complexes. These react with an excess of copper(II) halide to give CuL₂X complexes. From their i.r. spectra, all the complexes seem to be S-bonded to the metal. Thev(CuCl) vibration is identified at 236 cm^–1.     

Synthesis of esters of α-vinyloxyethylcarbamodithioic acid

Mono and diesters of 2-vinyloxyethylcarbamodithioic acid were synthesized by the reaction of (1-p-nitrophenyl)-2-vinyloxyethylaminoethanol with carbon disulfide. 3-[2-(Vinyloxyethyl)]-5-(4-nitrophenyl)-1,3-thiazolidine-2-thione was prepared and its structure was proved by X-ray diffraction analysis.     

INVESTIGATION OF THE THIAZOLE SERIES 7. SYNTHESIS,STRUCTURE AND PROPERTIES OF 2-HYDROXIMINO-1,3-THIAZOLIDINE-4-ONES

Abstract

Several 2-hydroximino-1,3-thiazolidine-4-ones have been prepared by reaction of the respective α-thiocyanatocarbonic acid esters with hydroxylamine. They have been characterized by ir, uv and ¹H-nmr. The chemical structure was determined unequivocally by the crystal structure analysis of 5-ethyl-2-hydroximino-1,3-thiazolidine-4-one, space-group: P2₁/c, a = 10.0382(7), b = 5.2903(4), c = 19.305(1) Å, β = 134.233(4) at T = 24(1)°C. The structural model was refined with 3196 data to give R = 0.044. Analysis of the bonding geometry has lead to characterization of the 2-amino-1,3-thiazolidine-4-ones as cyclic N-thiaiminoamides.     

A new chiral recognition in aminolysis of 3-acyl-4(r)-methoxycarbonyl-1,3-thiazolidine-2-thione with racemic amines

A chiral recognition was observed in aminolysis of 3-acyl-4(R)-methoxycarbonyl-1,3-thiazolidine-2-thione $\text{1}$ by racemic amine $\text{2}$ to give an optically active amide (S-excess) and amine (R-excess).     

Direct and Asymmetric Aldol Reactions of N-Azidoacetyl-1,3-thiazolidine-2-thione Catalyzed by Chiral Nickel(II) Complexes. A New Approach to the Synthesis of β-Hydroxy-α-Amino Acids

A direct and asymmetric triisopropylsilyltrifluoromethanesulfonate (TIPSOTf) mediated aldol reaction of N-azidoacetyl-1,3-thiazolidine-2-thione with aromatic aldehydes catalyzed by a chiral nickel(II)-Tol-BINAP complex has been developed (BINAP=2,2’-bis(diphenylphosphino)-1,1’-binaphthyl). The catalytic protocol gives the corresponding anti α-azido-β-silyloxy adducts with outstanding stereocontrol and in high yields. Theoretical calculations account for the stereochemical outcome of the reaction and lay the foundations for a mechanistic model. In turn, the easy removal of the thiazolidinethione yields a wide array of enantiomerically pure derivatives in a straightforward and efficient manner. Such a noteworthy character of the heterocyclic scaffold together with the appropriate manipulation of the azido group open a new route to the synthesis of di- and tripeptide blocks containing a β-aryl-β-hydroxy-α-amino acid.     

Direct,Enantioselective, and Nickel(II) Catalyzed Reactions of N-Azidoacetyl Thioimides with Trimethyl Orthoformate: A New Combined Methodology for the Rapid Synthesis of Lacosamide and Derivatives

A direct and highly enantioselective reaction of N-azidoacetyl-1,3-thiazolidine-2-thione with trimethyl orthoformate catalyzed by Tol-BINAPNiCl₂ in the presence of TESOTf and 2,6-lutidine is reported. The heterocyclic scaffold can be easily removed by addition of a wide array of amines to give the corresponding enantiomerically pure 2-azido-3,3-dimethoxypropanamides in high yields. Appropriate manipulation of the N-benzyl amide derivative provides an efficient access to the antiepileptic agent lacosamide through a new enantioselective C−C bond-forming process. DFT computational studies uncover clues for the understanding of the remarkable stereocontrol of the addition of a nickel(II) enolate to a putative oxocarbenium intermediate from trimethyl orthoformate.     

A new determination of the absolute configuration of the chiral amine

A new method for assignment of the absolute configuration of the asymmetric carbon atom attached to an amino or imino group using rac.-3-hexadecanoyl-4-methoxycarbonyl-1,3-thiazolidine-2-thione (rac.-HDMTT) ($\text{4}$) is described.     

Mixed ligand palladium(II) and platinum(II) complexes of tertiary diphosphines and benz-1,3-imidazoline-2-thione,benz-1,3-oxazoline-2-thione or benz-1,3-thiazoline-2-thione

Palladium(II) and platinum(II) complexes containing the mixed ligands tertiary diphosphines Ph₂P(CH₂) _n PPh₂, (n = 1–4) and benz-1,3-imidazoline-2-thione, benz-1,3-oxazoline-2-thione or benz-1,3-thiazoline-2-thione have been prepared and characterized by elemental analysis, magnetic susceptibility, molar conductance and i.r. spectral data. ³¹P–{¹H}-n.m.r. data have been applied to characterize the produced linkage isomers.     

A modular approach to marine macrolide construction. 3. Enantioselective synthesis of the C1-C28 sector of spongistatin 1 (altohyrtin A)

[structure: see text] A completely stereocontrolled approach to assembly of the major C1-C28 subunit of spongistatin 1 (altohyrtin A) is described. Key steps included the control of two asymmetric aldols by means of Fujita-Nagao (chiral N-acyl-1,3-thiazolidine-2-thione auxiliary) and Mukaiyama (BF3 x OEt2-promoted enolsilane coupling) protocols in complex settings.     

Zinc halide complexes of imidazolidine-2-thione and its derivatives: X-ray structures,solid state,solution NMR and antimicrobial activity studies

The preparation and characterization of zinc complexes of formula ZnL₂X₂ (X?=?Cl and Br), with L?=?1,3-diazinane-2-thione (Diaz), 1,3-diazipane-2-thione (Diap), imidazolidine-2-thione (Imt) and its methyl and n-propyl substituted derivatives, are described. The complexes dichlorobis(1-methylimidazolidine-2-thione-S)-zinc(II) (1) and dichlorobis(1-propylimidazolidine-2-thione-S)-zinc(II) (2) have been characterized by single-crystal X-ray methods. Both complexes adopt distorted tetrahedral geometry. Only intramolecular hydrogen bonding interactions are observed in 1 and 2. Solution and solid state ¹³C NMR show a significant shift of the C=S carbon resonance of the ligands, while other resonances are relatively unaffected, indicating that most likely the solid state structure is maintained in solution. Antimicrobial activity studies of the free ligands and their complexes show that ligands exhibit substantial antibacterial activities compared to the complexes.     

A new nonenzymatic chiral induction into prochiral meso compounds

The highly selective asymmetric induction into prochiral meso compounds has been developed by utilizing a functional heterocycle, 4(R methoxycarbonyl-l,3-thiazolidine-2-thione.