Reaction and Characterization of Thioamide Dianions Derived from N-Benzyl Thioamides

Transformation of Amides to Thioamides Using an Efficient and Novel Thiating Reagent

A convenient protocol was developed for the transformation of N-aryl-substituted benzamides to N-aryl-substituted benzothioamides using N-isopropyldithiocarbamate isopropyl ammonium salt as a novel thiating reagent. The major advantages of this protocol are its one-pot procedure, short reaction times, mild conditions, simple work-up, high yields and pure products.

Electrophile-Dependent Reactivity of Lithiated N-Benzylpyrene-1-Carboxamide

In this paper, we describe the lithiation of N-benzylpyrene-1-carboxamide with RLi-TMEDA. We found that the reaction outcome strongly depends on the electrophile used in the quenching step. The electrophile can be introduced at either the benzylic position or at the C-2 position in the pyrene nucleus. Furthermore, when H⁺ was used as the quencher, the product of the intramolecular carbolithiation of the pyrene K-region was formed. Dehydrogenation of the obtained compound with DDQ allowed the synthesis of a novel nitrogen polycyclic compound with an aza-benzo[c,d]pyrene (azaolympicene) skeleton. Attempts to extend the reaction scope to the amides substituted in the phenyl ring 8a and 8b gave an unexpected result. The reaction of both compounds with BuLi gave 1-valerylpyrene (9) in good yield. Photophysical properties, including absorption spectra, emission spectra and quantum yields of the emission of selected products, were studied and discussed.

Thiolate-Thione Redox-Active Ligand with a Six-Membered Chelate Ring via Template Condensation and Its Pt(II) Complexes

A new template condensation reaction has been discovered in a mixture of Pt(II), thiobenzamide, and base. Four complexes of the general form [Pt(ctaPh^R)₂], R = CH₃ (1a), H (1b), F (1c), Cl (1d), cta = condensed thioamide, have been prepared under similar conditions and thoroughly characterized by ¹H NMR and UV-vis-NIR spectroscopy, (spectro)electrochemistry, elemental analysis, and single-crystal X-ray diffraction. The ligand is redox active and can be reduced from the initial monoanion to a dianionic and then trianionic state. Chemical reduction of 1a with [Cp₂Co] yielded [Cp₂Co]₂[Pt(ctaPh^CH3)₂], [Cp₂Co]₂[1a], which has been similarly characterized with the addition of EPR spectroscopy and SQUID magnetization. The singly reduced form containing [1a]^1-, (nBu₄N)[Pt(ctaPh^CH3)₂], has been generated in situ and characterized by UV-vis and EPR spectroscopies. DFT studies of 1b, [1b]^1-, and [1b]^2- confirm the location of additional electrons in exclusively ligand-based orbitals. A detailed analysis of this redox-active ligand, with emphasis on the characteristics that favor noninnocent behavior in six-membered chelate rings, is included.

Iodine-mediated cyclization of N-thioacyl-1-(2-pyridyl)-1,2-aminoalcohols and their subsequent condensation leading to the formation of novel bis(1-imidazo[1,5-a]pyridyl)arylmethanes

The treatment of N-thioacyl-1-(2-pyridyl)-1,2-aminoalcohols with iodine and pyridine in THF at room temperature for 30 min leads to the formation of bis(1-imidazo[1,5-a]pyridyl)arylmethanes as green solids in good to high yields.

N-Phenyl-pyrrolidine-1-carbothio-amide

The title compound, C(11)H(14)N(2)S, was prepared by the reaction of 1-isothio-cyanato-benzene and pyrrolidine. In the crystal structure, inter-molecular N-H⋯S inter-actions are present.

N-Phenyl-piperidine-1-carbothio-amide

The title compound, C(12)H(16)N(2)S, was prepared by the reaction of with phenyl isothio-cyanate and piperidine. In the crystal structure, the mol-ecule exhibits inter-molecular N-H⋯S hydrogen bonds and weak intra-molecular C-H⋯S and C-H⋯N hydrogen-bonding inter-actions.

N-Thioacyl 1,3-Amino Alcohols: Synthesis via Ring-Opening of Oxiranes with Thioamide Dianions and Applications as Key Intermediates Leading to Stereochemically Defined 5,6-Dihydro-4H-1,3-oxazines and 1,3-Amino Alcohols

N-Thioacyl 1,3-amino alcohols were synthesized via the ring-opening of oxiranes with thioamide dianions generated from N-benzyl thioamides and BuLi in a highly regio- and stereoselective manner. The diastereomers of N-thioacyl 1,3-amino alcohols were readily separated by column chromatography to give stereochemically defined N-thioacyl 1,3-amino alcohols. They underwent intramolecular cyclization with Bu4F and EtI to give 5,6-dihydro-4H-1,3-oxazines. The reaction was specific with anti-N-thioacyl 1,3-amino alcohols, and cis-5,6-dihydro-4H-1,3-oxazines were obtained with high efficiency, whereas the reaction of a syn-alcohol gave a thioimidate as a major product. The reduction of N-thioacyl 1,3-amino alcohols with LiAlH4gave N-alkyl 1,3-amino alcohols in high yields. The use of optically active propylene oxide as a starting material gave the corresponding oxazine and alcohols in optically pure forms.

Synthesis of Tertiary Propargylamines by Sequential Reactions of in Situ Generated Thioiminium Salts with Organolithium and -magnesium Reagents

Sequential reactions of thioiminium salts generated from thioamides and methyl triflate with organolithium and -magnesium reagents proceed smoothly to give tertiary propargylamines in moderate to high yields. In all cases, two different organometallic reagents are incorporated into the starting thioamides.