Synthesis of macrocyclic systems derived from di-(2-indolyl)heteroarenes

A number of new 3,6-di-(2-indolyl)-dibenzofuran and carbazole derivatives have been prepared from dibenzofuran and carbazole linkers via the Fischer indole synthesis. The bis-indoles were successfully formylated at C3 and the resulting dicarbaldehydes were combined with diamines to generate indole based imine macrocyclic systems.     

Some electrophilic reactivity studies of di-(2-indolyl)dibenzofurans and di-(2-indolyl)carbazoles

3,6-Bis-(2-indolyl)dibenzofurans 1,2, and carbazoles 3–6 underwent a range of electrophilic substitution reactions to produce formyl indoles 7–12, biindolyls 24–28 and 33–34, glyoxylamides 40–42, and amides 48.     

Synthesis of 2,5-bis{(diethyl-3′-indolyl)methyl}furan and its N,N′-dimetallated complexes (lithium, sodium and potassium): X-ray crystal structures of 2,5-bis{(diethyl-3′-indolyl)methyl}furan and the polymeric tetrahydrofuran adduct of the dilithiated complex

The synthesis of 2,5-bis{(diethyl-3′-indolyl)methyl}furan by the acid catalysed condensation of 2,5-bis(diethylhydroxymethyl)furan with indole is presented. Dilithium, disodium and dipotassium derivatives are prepared by the reaction of the bis(indole) with n-BuLi, NaH and K, respectively, in the presence of various Lewis bases. The X-ray structures of 2,5-bis{(diethyl-3′-indolyl)methyl}furan and the dilithiated derivative (as a polymeric tetrahydrofuran adduct) are reported.     

Synthesis of a new macrocyclic compound and its self-assembly

A new macrocyclic compound has been synthesized by condensation of pyridine-1-oxide-2,6-dialdehyde with diethylenetria-mine. The self-assemly behaviours were studied by X-ray diffraction. The results show that the self-assembly were controlled by intermolecular hydrogen bonds and π-π stacking effects.     

2-(三甲氧基苯基)色胺盐酸盐的合成

2,3,4-及3,4,5-三甲氧基苯乙酮苯腙在多聚磷酸存在下进行Fischer反应,可生成相应的吲哚(1_a,1_b),但2,4,6-三甲氧基苯乙酮苯腙必须用无水氯化锌催化环化才能得到相应的吲哚(1_c)。1_a、1_b、1_c经Vilsmier反应生成相应的吲哚-3-醛(2_a,2_b,2_c);经与硝基甲烷缩合得到相应的2-(三甲氧基苯基)-3-(2-硝基乙烯基)吲哚(3_a,3_b,3_c);3_a及3_b用LiAlH₄还原即可制备成相应的色胺盐酸盐(4_a和4_b),3_b还被制成苦味酸盐(4_b)。     

Multicomponent reactions for the synthesis of new 3′-indolyl substituted heterocycles under microwave irradiation

A series of polysubstituted (3′-indolyl)pyrazolo[3,4-b]pyridine and (3′-indolyl)benzo[h]quinoline derivatives were synthesized via one-pot multicomponent reactions of aldehydes, 3-cyanoacetyl indoles with 5-aminopyrazol or naphthylamine under microwave irradiation. Particularly valuable features of this method include high yields of products, broad substrate scope, short reaction time and straightforward procedure.     

Synthesis of symmetrical and unsymmetrical diindolylmethanes via acid-catalysed electrophilic substitution reactions

A range of activated indole-2-carboxylate derivatives was prepared via the Hemetsberger indole synthesis. Vilsmeier formylation was explored to establish regioselectivity and to prepare a range of new indole carbaldehydes. The indole aldehydes were reduced to the corresponding hydroxymethylindoles in good yields by the use of sodium borohydride in THF. Symmetrical 4,4′-, 6,6′- and 7,7′-diindolylmethanes were prepared via the acid-catalysed reaction of the corresponding hydroxymethylindoles. Furthermore, the treatment of methyl 4-hydroxymethyl-5,6-dimethoxyindole-2-carboxylate and a range of methyl indole esters with acetic acid led to the formation of unsymmetrical 4,6′- and 4,7′-dindolylmethanes.     

Facile Synthesis of Some 3-(Benzimidazol-2-yl)- and 3,6-Di(Benzimidazol-2-yl)-9-ethyl-9H-carbazoles

A simple and efficient synthesis of novel 3-(benzimidazol-2-yl)- and 3,6-di(benzimidazol-2-yl)-9-ethyl-9H-carbazoles is described. The synthetic approach for the preparation of 2-substituted benzimidazoles 4–8 and bis-benzimidazoles 9–12 was achieved by the condensation of carbazole-3-carbaldehyde 2 and carbazole-3,6-dicarbaldehyde 3 with o-phenyldiamines in dimethylformamide or dimethylsulfoxide in moderate to excellent yield. The identities of synthesized compounds were confirmed using ¹H NMR, ¹³C NMR, infrared (IR), and high-resolution mass spectrometry (HRMS).     

Synthesis of 5-aryl-5′-formyl-2,2′-bithiophenes as new precursors for nonlinear optical (NLO) materials

A series of formyl-substituted 5-aryl-2,2′-bithiophenes 5 were synthesized using two different methods: Vilsmeier-Haack-Arnold reaction (VHA) or through Suzuki coupling. The synthesis of compounds 5 through the Vilsmeier-Haack-Arnold reaction, starting from inexpensive and easily available precursors such as acetophenones, gave the title compounds in low yields after four reaction steps. On the other hand Suzuki coupling of functionalized arylboronic acids 7 and the 5-bromo-5′-formyl-2,2′-bithiophene 6 gave compounds 5 in good yields in only one step.     

Rotamerisation and intramolecular proton transfer of 2-(2′-hydroxyphenyl)oxazole, 2-(2′-hydroxyphenyl)imidazole and 2-(2′-hydroxyphenyl)thiazole: a theoretical study

Semi-empirical (AM1-SCI) calculations have been performed on 2-(2′-hydroxyphenyl)oxazole (HPO), 2-(2′-hydroxyphenyl)imidazole (HPI) and 2-(2′-hydroxyphenyl)thiazole (HPT) to rationalise the photophysical behaviour of the compounds exhibiting intramolecular rotation as well as excited state intramolecular proton transfer (ESIPT). The calculations reveal that there is a gradual variation in the properties from HPO to HPT through HPI so far as the existence of the rotational isomers in the ground state is concerned. While HPO gives rise to two stable rotamers (I and II) in all the common solvents, there is only one stable species for HPT in the S₀ state. For HPI, rotamer II is possible only in the isolated state and/or in solvents of low polarity, but in high polar solvents it gives rise to the normal form (I) only. For all the molecules in the series, however, intramolecular proton transfer (IPT) takes place in the lowest excited singlet (S₁) and the triplet (T₁) states. Combination of the rotamerism and ESIPT gives rise to multiple fluorescence bands for the fluorophores. Theoretical assignments have been made for the excitation, fluorescence and phosphorescence bands. Simulated potential energy curves (PEC) in different electronic states reveal that the IPT process is feasible in either of the S₁ and T₁ states but not in the ground state. The ESIPT reaction has been found to be favoured both thermodynamically and kinetically in these electronic states compared to the ground state. However, quantum mechanical tunnelling has been proposed for the prototropic reaction to proceed in the excited states.     

Synthesis and characterizations of 3,3′-bis(diphenylphosphinoamine)-2,2′-bipyridine and 3,3′-bis(diphenylphosphinite)-2,2′-bipyridine and their chalcogenides

New bis(phosphinoamine) and bis(phosphinite) derivatives of 2,2′-bipyridine were prepared through a single step reaction of 3,3′-diamino-2,2′-bipyridine or 3,3′-dihydroxy-2,2′-bipyridine with diphenylchlorophosphine, respectively. Their P = E chalcogenides (E = O, S, Se) were also prepared. All the new compounds were characterized by elemental analysis, IR and NMR spectroscopies. The molecular structure of 3,3′-bis(diphenylthiophosphinite)-2,2′-bipyridine was elucidated by single-crystal X-ray crystallography.     

Synthesis,spectra and X-ray crystal structure of a new type of macrocyclic hexanuclear iron(III) cluster

A macrocyclic iron(III) 18-azametallacrown-6 compound, [Fe₆(5-Brashz)₆(H₂O)₆]?·?20H₂O(5-Brashz?=?N-acetyl-(5-bromosalicylhydrazide)), where the pentadentate ligands bridge the metal ions, was synthesized and characterized. Due to the meridional coordination of the ligand to the metal ion, the ligand is not only bridging the ring metal ions using a hydrazide N–N group, but also enforcing the stereochemistry of the metal ions as a propeller shape with alternating Λ/Δ configuration. The disc-shaped hexanuclear cluster is about 14.5?Å in diameter, 16.8?Å in thickness and has a vacant cavity in the center of the cluster.     

Macrocyclic cobalt(III) complexes as precursors for metal-polythiophene hybrid materials

A thiophene-functionalised macrocyclic ligand trans-6,13-dimethyl-6-((thiophen-3-ylmethyl)amino)-1,4,8,11-tetraazacyclotetradecane-13-amine (L¹) has been prepared and complexed with Co^III. The ligand L¹ binds as a pentadentate in the crystallographically characterised complexes [CoL¹(OAc)](ClO₄)₂ and [CoL¹Cl]Cl₂. Electro-copolymerisation of [CoL¹Cl]Cl₂ with 3,4-ethylenedioxythiophene (EDOT) in a 1:2 ratio on a preformed poly-3,4-ethylenedioxythiophene (PEDOT) film resulted in metal–polymer hybrid films of high quality, consistency and uniformity in appearance. The copolymerised films were characterised by XPS indicating a 1:11 ratio of incorporation of complex to EDOT. Electrochemistry of the Co-PEDOT film (cast on an indium-doped tin oxide working electrode) in water revealed a Co^III/II redox couple at a potential ca. −600 mV (vs Ag/AgCl) which is similar to that seen in solution for the monomeric aqua complex [CoL¹(OH₂)]³⁺.     

Highly diastereoselective chemoenzymatic synthesis of (2′R)- and (2′S)-2′-deoxy[2′-H]guanosines

In an effort to develop an efficient synthetic method of highly diastereoselective (2′R)- and (2′S)-2′-deoxy[2′-²H]guanosines, chemoenzymatic conversion was investigated. The synthesis of (2′R > 98% de)-2′-deoxy[2′-²H]guanosine was achieved by biological transdeoxyribosylation using (2′R > 98% de)-2′-deoxy[2′-²H]uridine, 2,6-diaminopurine, and Enterobacter aerogenes AJ-11125, followed by treatment with adenosine deaminase. (2′S > 98% de)-2′-Deoxy[2′-²H]guanosine was synthesized from (2′S > 98% de)-2′-deoxy[2′-²H]uridine and 2,6-diaminopurine using thymidine phosphorylase and purine nucleoside phosphorylase instead of E. aerogenes AJ-11125.     

Synthesis of a 4′,4′-spirothietane-2′, N-cycloadenosine as a highly constrained analogue of 5′-deoxy-5′-methylthioadenosine (MTA)

The synthesis of the highly constrained adenosine derivative 7 featuring at spirothietane at C-4′, which may be considered as a rigid analogue of MTA, is described.     

新型螺[氧化吲哚-3,3′-吡唑]-5′-二氟甲基-4′-甲酸酯类化合物的合成

以原位生成的二氟甲基重氮甲烷（CF₂HCHN₂）与靛红衍生的3-烯基氧化吲哚为原料,通过[3+2]环加成反应和1,3-H迁移过程,合成了3种结构新型的螺[氧化吲哚 3,3′-吡唑]-5′-二氟甲基-4′-甲酸酯类化合物,收率41~68%, dr 91: 9~99 : 1,其结构经¹H NMR, ¹³C NMR, ¹⁹F NMR和HR-MS(ESI-TOF)表征。并通过单晶X-射线单晶衍射确定其相对构型。     

Synthesis of new fluorescent 2-(2′,2″-bithienyl)-1,3-benzothiazoles

Bithienyl-1,3-benzothiazole derivatives were synthesised by reacting various 5-formyl-5′-alkoxy- or 5-formyl-5′-N,N-dialkylamino-2,2′-bithiophenes with ortho-aminobenzenethiol in good to excellent yields. Evaluation of the fluorescence properties of these compounds was carried out. They show strong fluorescence in the 450-600 nm region, as well as high quantum yields and large Stokes’ shifts.     

Synthesis of 1,2′- and 1,3′-bipyrroles from 2- and 3-nitropyrroles

1,2′- and 1,3′-Bipyrroles, which are attractive precursors for the synthesis of bipyrrole-based natural products, are synthesized in one-pot from 2- and 3-nitropyrroles by a sequential nitro group reduction—Paal-Knorr pyrrole synthesis.     

Synthesis,structure and reactivity of a macrocyclic imine: aza-[13]-macrodiolides

The in situ synthesis and subsequent reactions of macrocylic imine 2 are reported. The imine was trapped with cyanotrimethylsilane to give α-amino nitrile aza-[13]-macrodiolides in a 1:1 ratio of diastereomers. A crystal structure of the syn α-cyano nitrile diastereomer, 7a, provided insights into the lack of selectivity in reactions of 2 relative to macrocyclic alkene 1. Reactions to functionalize the syn diastereomer 7a are also reported.     

Synthesis, characterization and crystal structures of di-three-coordinated copper(I) macrocyclic Schiff base complexes

The air-stable di-copper(I) complexes Cu₂L(SCN)₂ (1) and Cu₂L(SCN)_1.86I_0.14 (2) of the N₄ macrocyclic Schiff base ligand L have been synthesized and characterized by IR, elemental analysis, UV-Vis and crystal structure determination. X-ray analysis of the complexes shows an approximate distorted trigonal planar geometry around each copper(I) ion that is constructed from one N-bonded thiocyanate (or iodide in 2) group and two imine nitrogen atoms. DFT calculations were used to determine the structural features of the Cu₂L(SCN)₂ complex, and these were consistent with the experimental data for the complex.