Synthesis and isomerization of imino-fused N-confused porphyrin

[reaction: see text] A set of mutually interconvertable inner-bridged-type porphyrinoids, imino-fused N-confused porphyrins (IF-NCPs), which possess a [5.7.5] tricyclic ring in the core, were synthesized from a condensation reaction of 21-amino-substituted NCP and an arylaldehyde, and the structures were characterized by X-ray single-crystal analysis.     

Synthesis and spectroscopy of a series of substituted N-confused tetraphenylporphyrins

A series of N-confused tetraphenylporphyrins (H(2)NCTPPs) with substituents on either the para- or the 3,5-positions of the meso phenyl rings were prepared using Lindsey conditions. Both electron-withdrawing and electron-donating groups were chosen in order to probe the effects of peripheral substitution on the properties of the macrocycles. The series includes 5,10,15,20-tetra-(4-R-phenyl) N-confused porphyrins (where R = bromo (1), iodo (2), cyano (3), methoxy (4), 2',5'-dimethoxyphenyl (5), or ethynyl (6)) and 5,10,15,20-(3,5-di-tert-butylphenyl) N-confused porphyrin (7). Absorption and steady-state fluorescence measurements were carried out, and quantum yields were measured for all compounds in both dichloromethane (CH(2)Cl(2)) and dimethylacetamide (DMAc).     

Facile peripheral modification of N-confused porphyrin

[reaction: see text] An improved methodology for the N-alkylation of the porphyrin isomer N-confused porphyrin is presented. The combination of polar solvent conditions and the use of the base Cs2CO3 affords externally modified products in high yield without separation difficulties and without the use of large excesses of alkylating reagent. The further transformation and metalation of these products provides opportunities for the construction of metalloenzyme model complexes, peptide adducts, and chromophore assemblies.     

Regulation of NH-tautomerism in N-confused porphyrin by N-alkylation

A variety of internally N-alkylated N-confused porphyrins were prepared in a stepwise manner through the protection of the reactive peripheral nitrogen atom. NH-Tautomerism in N-confused porphyrins was found to be regulated by N-alkylation, which enabled us to obtain discrete information on two important NH-tautomers of an N-confused porphyrin.     

Extension of N-confused porphyrin by an o-xylene fragment

[reaction: see text] A simple method of modification of N-confused porphyrin is provided by reactions of 5,10,15,20-tetraaryl-2-aza-21-carbaporphyrin with alpha,alpha'-dibromoxylene. The N-bromoxylene-substituted monomer formed in a first step of alkylation can be converted to the products with the extended structure on the N-confused pyrrole for which formation of organometallic silver(III) complexes has been shown.     

Dimeric and monomeric forms of manganese N-confused porphyrin

The synthesis and structural characterization of a manganese adduct of N-confused tetraphenylporphyrin (NCTPP) is presented; in the absence of coordinating ligands this complex forms a novel dimer structure and demonstrates a potential manganese agostic interaction with the interior pyrrolic CH as seen in other first row transition metal NCTPP compounds.     

The synthesis of isostructural Mo2+ porphyrin and N-confused porphyrin complexes

We have synthesized the first early transition metal N-confused porphyrin complex Mo(NCTPP)(pip)2; this species is isostructural to its normal porphyrin analog Mo(TPP)(pip)2 but exhibits significant electronic differences arising from the inversion of a single pyrrolic group.     

Endocyclic extension of porphyrin pi-system in etheno-bridged N-confused tetraphenylporphyrin

Etheno-bridged N-confused tetraphenylporphyrin was synthesized through flipping of the confused pyrrole ring and endocyclic extension of [18]annulenic pi-conjugated system was exemplified by the absorption spectra as well as the calculated Kohn-Sham orbitals.     

Unprecedented formation of a rhodium cluster triggered by rhodium-fastened N-confused gable porphyrin

Thermal reaction of N-confused porphyrin (NCP) with [RhCl(CO)2]2 caused unprecedented formation of tetranuclear rhodium complex Rh4(NCP)2(CO)4 having a gable-porphyrin-type structure, where two porphyrin pi systems were electronically connected by the rhodium cluster.     

Alkyl substituted 3-PPP derivatives. Synthesis and biological investigation

Synthesis of alkyl substituted derivatives of 3-(1-propyl)3-piperidinyl)phenol ( 3-PPP ), 2–8 , was carried out in an attempt to improve on the pharmacodynamic properties of 3-PPP. No significant improvement was attained.     

Synthesis and characterization of transition metal complexes of dimeric N-confused porphyrin linked by an o-xylene fragment

Insertion of nickel(II), zinc, cadmium, or silver(III) into both macrocyclic crevices of 2,2'-o-xylene-bis(5,10,15,20-tetrakis(p-tolyl)-2-aza-21-carbaporphyrin) results in homometallic dimeric complexes which were isolated and characterized by NMR, UV-vis, mass spectrometry, and cyclic voltammetry. The 1H NMR study of these systems at low temperatures (203-233 K) allowed determination of most stable conformers with respect to a rotational freedom around the xylene bridge. An unfolded conformation for the dicationic bis(silver(III)) complex was determined on the basis of 2D nuclear Overhauser effect spectrometry experimentation. A mixture of nonequally populated diastereomers is observed for bis(zinc) and bis(cadmium) complexes due to a possibility of two different orientations of the apical anionic ligands with respect to the bridge. In a reaction of 5,10,15,20-tetrakis(p-tolyl)-2-aza-21-carbaporphyrinato nickel(II) with 2-(o-bromoxylene)-5,10,15,20-tetrakis(p-tolyl)-2-aza-21-carbaporphyrin in the presence of a proton scavenger, two isomeric bis(N-confused porphyrin) complexes with one subunit "empty" and the other metalated by nickel(II) were obtained. In the product 10, the o-xylene links external nitrogens of the subunits while product 11 consists of the xylene bridge between external nitrogen of the nonmetalated subunit and internal carbon of the fragment containing a nickel(II) ion. The products were characterized by mass spectrometry, UV-vis, NMR, and, in the case of complex 11, also by X-ray crystallographic analysis (space group P1, a =17.007(3), b = 18.130(3), c = 18.797(2) A, alpha = 105.856(13) degrees, beta = 107.447(13) degrees, gamma = 98.818(15) degrees, V = 5141.1(15) A3, Z = 2). Insertion of zinc or silver(III) into an empty crevice of 10 resulted in heterometallic zinc-nickel(II) or silver(III)-nickel(II) complexes 12 or 13, respectively, which were characterized by NMR, UV-vis, and cyclic voltammetry. The subunits in the bis(porphyrin) systems retain spectroscopic and redox properties typical for monomeric complexes.     

新型链状双取代二茂铁甲酸酚酯的合成

由双取代二茂铁甲酰氯与烷基酚反应，合成了具有新型链状结构的八个二茂铁双取代衍生物。     

Synthesis of substituted 1,3,4-oxadiazole derivatives

Monosubstituted oxadiazoles were synthesized by the reaction of hydrazides with triethyl orthoformate. Their reactions with benzoyl chloride gave benzoylcarbohydrazides, which under the action of thionyl chloride were cyclized to the respective 2,5-disubstituted oxadiazoles. 1-Aryl-4-(5-thioxo-4,5-dihydro-1,3,4-oxadiazol-2-yl)-pyrrolidin-2-ones were synthesized from acid hydrazides using carbon disulfide under basic conditions. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 269-272, February, 2009.     

Synthesis of heterocyclic substituted norcantharidin derivatives

Twenty novel norcantharidin derivatives, which were substituted by thiazole ring, were synthesized in a single step by the [3+2] 1,3‐dipolar cycloaddition reaction with oxime or hydrazone in the presence of chloramine‐T when compared with the conventional method. J. Heterocyclic Chem., (2011).     

Synthesis and crystal structure of the first lanthanide complex of N-confused porphyrin with an eta2 agostic C-H interaction

The reaction of Ln[N(SiMe3)2]3.[LiCl(THF)3](x)(Ln = Yb and Er) with N-confused tetraphenylporphyrin (H2NCTPP) followed by Na(L(OMe))(L(OMe)=(eta5-C5H5)Co[P(=O)(OMe)2]) gives (NCTPP)Ln(L(OMe)), whose X-ray structures exhibit an eta2 agostic interaction between the metal centre and the inner C-H bond of the NCTPP ligand.