Efficient synthesis of (+)-1,8,8a-tri-epi-swainsonine, (+)-1,2-di-epi-lentiginosine, (+)-9a-epi-homocastanospermine and (-)-9-deoxy-9a-epi-homocastanospermine from a D-glucose-derived aziridine carboxylate, and study of their glycosidase inhibitory activities

The utility of a D-glucose-derived aziridine carboxylate was demonstrated for the synthesis of polyhydroxylated quinolizidine and indolizidine alkaloids. The chemoselective reduction of 1 followed by two-carbon homologation by the Wittig reaction afforded gamma,delta-aziridino-alpha,beta-unsaturated ester 9, which on regioselective nucleophilic aziridine ring opening either by using water as a nucleophile or hydrogenation afforded delta-lactams 11/16--true synthons for the synthesis of four structurally different iminosugars, namely quinolizidine alkaloids 5b/5c, swainsonine 6b and lentiginosine 7b analogues. Glycosidase inhibitory activities of these iminosugars were investigated.     

Crystal Structure of 1,1-Dichloro-3-Dichloromethyl-1a-3-Dipenyl-1a,2,3,4-Tetrahydro-1 H-Azirino〔1,2-a〕〔1,5〕benzodiazepine(C_(23)H_(18)Cl_4N_2)

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Synthesis, structural characterization, antimicrobial and cytotoxic effects of aziridine, 2-aminoethylaziridine and azirine complexes of copper(II) and palladium(II)

The synthesis, spectroscopic and X-ray structural characterization of copper(II) and palladium(II) complexes with aziridine ligands as 2-dimethylaziridine HNCH(2)CMe(2) (a), the bidentate N-(2-aminoethyl)aziridines C(2)H(4)NC(2)H(4)NH(2) (b) or CH(2)CMe(2)NCH(2)CMe(2)NH(2) (c) as well as the unsaturated azirine NCH(2)CPh (d) are reported. Cleavage of the cyclometallated Pd(II) dimer [μ-Cl(C(6)H(4)CHMeNMe(2)-C,N)Pd](2) with ligand a yielded compound [Cl(NHCH(2)CMe(2))(C(6)H(4)CHMe(2)NMe(2)-C,N)Pd] (1a). The reaction of the aziridine complex trans-[Cl(2)Pd(HNC(2)H(4))(2)] with an excess of aziridine in the presence of AgOTf gave the ionic chelate complex trans-[(C(2)H(4)NC(2)H(4)NH(2)-N,N')(2)Pd](OTf)(2) (2b) which contains the new ligand b formed by an unexpected insertion and ring opening reaction of two aziridines ("aziridine dimerization"). CuCl(2) reacted in pure HNC(2)H(4) or HNCH(2)CMe(2) (b) again by "dimerization" to give the tris-chelated ionic complex [Cu(C(2)H(4)NC(2)H(4)NH(2)-N,N')(3)]Cl(2) (3b) or the bis-chelated complex [CuCl(C(2)H(2)Me(2)NC(2)H(2)Me(2)NH(2)-N,N')(2)]Cl (4c). By addition of 2H-3-phenylazirine (d) to PdCl(2), trans-[Cl(2)Pd(NCH(2)CPh)(2)] (5d) was formed. All new compounds were characterized by NMR, IR and mass spectra and also by X-ray structure analyses (except 3b). Additionally the cytotoxic effects of these complexes were examined on HL-60 and NALM-6 human leukemia cells and melanoma WM-115 cells. The antimicrobial activity was also determined. The growth of Gram-positive bacterial strains (S. aureus, S. epidermidis, E. faecalis) was inhibited by almost all tested complexes at the concentrations of 37.5-300.0 μg mL(-1). However, MIC values of complexes obtained for Gram-negative E. coli and P. aeruginosa, as well as for C. albicans yeast, mostly exceeded 300 μg mL(-1). The highest antibacterial activity was achieved by complexes 1a and 2b. Complex 2b also inhibited the growth of Gram-negative bacteria.     

三氟亚乙基取代的N-苯甲酰基氮杂环丙烷的合成

发展了一种制备三氟亚乙基取代的N-苯甲酰基氮杂环丙烷的新颖方法. 三氟甲基取代的炔丙胺化合物1在盐酸作用下脱去叔丁基亚磺酰基得到三氟甲基炔丙胺盐酸盐2, 当用NaOH作碱对2进行苯甲酰化反应时意外地以中等产率获得了N-苯甲酰基-2-三氟亚乙基氮杂环丙烷类化合物3a～3c. 在类似条件下也可以从1出发采用“一锅法”制得氮杂环丙烷3d和3e. 化合物3b可以在酸催化下发生开环反应得到化合物6b. 化合物3和6的结构经IR, 1H NMR, 19F NMR, MS, HRMS和元素分析进行确证.     

Regioselective reactions of mesyloxymethylazetidinones with nucleophiles I. Cleavage of the azetidinone ring,azetidinone‐aziridine ring transformations

The reaction of 4‐mesyloxymethylazetidin‐2‐one derivatives 3 with ammonia and sodium methoxide was investigated. The two electrophilic centers of the substrate reactesuccessively, resulting in cleavage of the lactam bond and formation of a new aziridine ring. The resulting type 6 and 8 aziridinylacetic acid derivatives are related to the novel 2‐(aziridin‐2‐yl)‐3‐phenylpropionic acid type carboxypeptidase A inhibitors and, as such, potential drug candidates.     

Interactions of aziridines with nickel complexes: oxidative-addition and reductive-elimination reactions that break and make C-N bonds

Reaction of the N-tosylaziridines (p-CH(3)C(6)H(4)SO(2))NCH(2)CHR (1a, R = H; 1b, R = Me; 1c, R = n-Bu; 1d, R = i-Pr) with (bpy)Ni(cod) (2; bpy = 2,2'-bipyridine; cod = 1,5-cyclooctadiene) or (bpy)NiEt(2) (3) results in elimination of cod or butane from 2 and 3, respectively, and oxidative addition of an aziridine C-N bond to give the azametallacyclobutane complexes (bpy)Ni(NTosCHRCH(2)) (4a, R = H; 4b, R = Me; 4c, R = n-Bu; 4d, R = i-Pr) as maroon solids in 50-70% isolated yields. The structure of 4b exhibits a puckered four-membered azametallacycle containing a pyramidal nitrogen and with Ni-N(1) = 1.911(5) A; the tosyl group on N and the methyl substituent on the adjacent C are disposed in an anti conformation. The monodeuterated aziridine syn-(p-CH(3)C(6)H(4)SO(2))NCHDCH-n-Bu (1e) reacts with either 2 or 3 to give (bpy)Ni[NTosCH(n-Bu)CHD] (4e) in 60-65% yield, having an anti arrangement of the methine and methylene protons in the azametallacycle, and indicates that >95% inversion of stereochemistry has occurred at the methylene carbon during the oxidative-addition reaction. When the azametallacyclobutane complexes 4a-e are exposed to oxygen, oxidatively induced reductive elimination ensues, giving the free aziridines in 30-60% isolated yields. In the oxidation of 4e, the product aziridine is spectroscopically identical to its parent, 1e, indicating the elimination that forms the C-N bond also proceeds with inversion of stereochemistry (approximately 92% by (1)H NMR) at the methylene carbon.     

The crystal and molecular structure of 1-(p-iodobenzenesulfonyl)-1-azaspiro[2,5] octane

The structure of 1-(p-iodobenzenesulfonyl)-1-azaspiro[2.5]octane was determined by a single-crystal x-ray diffraction study. The compound crystallizes in the orthorhombic space group P2₁ 2₁ 2₁ with cell dimensions: a = 11.65₅, b = 11.82₅, c = 11.06₈ ± 0.002 Å. The aziridine ring is spiro-fused to the cyclohexane ring with the nitrogen atom occupying the equatorial position. The cyclohexane ring is in an undistorted chair conformation and forms a dihedral angle of 97.1° with the aziridine ring. The structure was refined to a final value of R = 0.07₄ for the 590 independent reflections.     

Reversible Deactivation Radical Polymerization of Monomers Containing Activated Aziridine Groups

Polymers bearing activated aziridine groups are attractive precursors to α‐substituted‐β‐amino‐functionalized materials due to the enhanced reactivity of the pendant aziridine functionalities toward ring‐opening by nucleophiles. Two aziridine‐containing styrenic monomers, 2‐(4‐vinylphenyl)aziridine (VPA) and N‐mesyl‐2‐(4‐vinylphenyl)aziridine (NMVPA), were polymerized under a variety of reversible deactivation radical polymerization conditions. Low‐catalyst‐concentration atom transfer radical polymerization (LCC‐ATRP) and reversible addition‐fragmentation chain‐transfer (RAFT) polymerization were ineffective at producing well‐defined polymers from VPA due to side reactions between the aziridine functionalities and the agents controlling the polymerizations (catalysts or chain transfer agents). PolyVPA produced under nitroxide‐mediated polymerization (NMP) conditions had narrow molecular weight distribution at low to moderate conversions of monomer, but branched and eventually cross‐linked polymers were formed at higher conversions due to ring‐opening reactions of the aziridine groups. Most of these undesirable side reactions were eliminated by attaching a methanesulfonyl (mesyl) group to the aziridine nitrogen atom, and well‐defined linear homopolymers with targeted molecular weights were realized from NMVPA under RAFT and NMP conditions; however, side reactions between the aziridine groups and the catalyst in LCC‐ATRP still occured and the polymerization was uncontrolled using this technique.

     

Crystal and molecular structure of 6-(p-bromobenzoyl)-6-azabicyclo[3.1.0]hexane

The molecular structure of 6-(p-bromobenzoyl)-6-azabicyclo[3.1.0]hexane has been determined by a single crystal, three-dimensional x-ray study. The compound crystallizes in the monoclinic space group (P) with four molecules in a unit cell of dimensions a = 8.83, b = 10.15, c = 12.63 ± 0.02Å and β = 94°55′ ± 5′. The aziridine ring is eis fused to the cyclopentane ring with the two rings together in a boat conformation. The fusion angle of the two rings is 110.8°. The aziridine ring has all angles of 60 ±1° and all bond distances of 1.48 ± 0.03Å. The cyclopentane ring has alternately long (1.61 ± 0.04Å) and short (1.52 ± 0.02Å) distances. Non-fusion angles in the cyclopentane ring are 106.0 ± 0.5°. Other molecular parameters are as anticipated. The 844 independent reflections obtained were refined to a final value of R = 0.11₆ using full-matrix least squares techniques.     

Solvent- and temperature-dependent functionalisation of enantioenriched aziridines

A highly stereo‐ and regioselective functionalisation of chiral non‐racemic aziridines is reported. By starting from a parent enantioenriched aziridine and finely tuning the reaction conditions, it is possible to address the regio‐ and stereoselectivity of the lithiation/electrophile trapping sequence, thereby allowing the preparation of highly enantioenriched functionalised aziridines. From chiral N‐alkyl trans‐2,3‐diphenylaziridines (S,S)‐ 1 a , b , two differently configured chiral aziridinyllithiums could be generated (trans‐ 1 a , b‐Li in toluene and cis‐ 1 a , b‐Li in THF), thus disclosing a solvent‐dependent reactivity that is useful for the synthesis of chiral tri‐substituted aziridines with different stereochemistry. In contrast, chiral aziridine (S,S)‐ 1 c showed a temperature‐dependent reactivity to give chiral ortho‐lithiated aziridine 1 c‐ ortho ‐Li at ?78 °C and α‐lithiated aziridine 1 c‐α‐Li at 0 °C. Both lithiated intermediates react with electrophiles to give enantioenriched ortho‐ and α‐functionalised aziridines. The reaction of all the lithiated aziridines with carbonyl compounds furnished useful chiral hydroxyalkylated derivatives, the stereochemistry of which was ascertained by X‐ray and NMR spectroscopic analysis. The usefulness of chiral non‐racemic functionalised aziridines has been demonstrated by reductive ring‐opening reactions furnishing chiral amines that bear quaternary stereogenic centres and chiral 1,2‐, 1,3‐ and 1,5‐aminoalcohols. It is remarkable that the solvent‐dependent reactivity observed with (S,S)‐ 1 a , b permits the preparation of both the enantiomers of amines ( 11 and ent‐ 11 ) and 1,2‐aminoalcohols ( 13 and ent‐ 13 ) starting from the same parent aziridine. Interestingly, for the first time, a configurationally stable chiral α‐lithiated aziridine ( 1 c‐α‐Li ) has been generated at 0 °C. In addition, ortho‐hydroxyalkylated aziridines have been easily converted into chiral aminoalkyl phthalans, which are useful building blocks in medicinal chemistry.     

Synthesis and Crystal Structure of 2,3-Dihydroxymethyl-N-cyclohexylaziridine

1 INTRODUCTION It is well known that aziridine compounds are wi- dely present in many natural products[1～3]. They contain unique nitrogen skeletons of three-membe- red heterocycles. Aziridine derivatives are also hi- ghly versatile synthetic precursors and have been used as synthons for chiral amines, amino acids, amino alcohos, alkaloids, and β-lactam antibiotics[4, 5]. On the basis of previous work, we have performed the tandem asymmetric Michael addition/internal nucleophilic substit…     

Synthesis and Crystal Structure of 5-Methoxy- butyrolacto[3,4-b]-1-N-cyclohexylaziridine

1 INTRODUCTION The study of aziridine derivatives has been an ac-tive area in organic chemistry due to their interestingreactive properties and special structures[1～3]. Aziri-dine compounds contain unique nitrogen skeleton ofthree-membered heterocycle, which is widely presentin many natural products. They have been used toobtain a variety of biologically important moleculessuch as amino acids, amino alcohols, alkaloids, andβ-lactam antibiotics[2～4]. Although the synthetic routesto azir…     

Some reactions of diazomethane with polyfluoroazaolefins

The reactons of some polyfluoroazaolefins with diazomethane are described. Thus 5-H-decafluoro-2-aza-hex-2-(Z)-ene yields 1-trifluoro-methyl-2-fluoro-2-(1,1,2,3,3,3-hexafluoropropyl)-aziridine as the sole isolable product. However, undecafluoro-2-azahex-2(Z)-ene yields not only the corresponding aziridine, 1-trifluoromethyl-2-fluoro-2-(heptafluoropropyl) aziridine, but also 1-trifluoromethyl-5-(heptafluoropropyl)-1,2,3-triazole, and 1-trifluoromethyl-2-fluoromethyl-2-(heptafluoropropyl) aziridine. 5-H-octafluoro-2-azahexa-2(Z)4(Z)-diene yielded the expected aziridine and 1-trifluoromethyl-2-fluoromethyl-2-(1,1,3,3,-tetra-fluoroprop-2-enyl)aziridine. No products were observed as a result of reactions at the C = C bond and no triazole was isolated in this case. Nonafluoroazacyclohex-1-ene gave the corresponding aziridine and a small amount of a compound believed to be 2,2,3,3,4,4,5,5-octafluoro-1,8,9-triazabicyclo [4,3,0] nonadiene i.e. the triazole product.     

Synthese von racemischen Aminozuckersäure-lactonen: xylo- und lyxo-2,3-Diacetylamino-5-acetoxypentan-4-olid und -2,3,5-Triacetylaminopentan-4-olid

Synthesis of Racemic Aminosugar Lactones: xylo- and lyxo-2,3-Diacetylamino-5-acetoxypentan-4-olide and -2,3,5-Triacetylaminopentan-4-olide Starting with 5-hydroxy-2-penten-4-olide ( 1 ), the tricyclic intermediate 4 was prepared via the chloride 2 , the acyl azide 3 , and an intramolecular nitrene addition (Scheme 3). Azide ion opened the aziridine ring in 4 at C(α) to give 5 , which was transformed via 7 into one of the title compounds, the triacetylated diamino-hydroxy-lactone 13 (Scheme 4). An alternative conversion of 4 into 13 involved the synthesis of the N-acetylaziridine 10 , the opening of the 3-ring of 10 with N to form 12 , and a final reductive acetylation (Scheme 5). The third N-substituent was introduced at C(δ) of 13 by the following sequence: hydrolysis of the AcO group (→ 14 ), mesylation (→ 15 ), substitution by N (→ 16 ), and reductive acetylation to yield the other title compound, the triacetylated triaminolactone 17 (Scheme 6). Since the ring opening of aziridines by nucleophiles occurs by inversion, the primary products 5a and 12a of the N reactions as well as the substances derived from them, i.e. 6a , 7a , and 13a - 17a , have the xylo-configuration ( a -series). Under some of the reaction conditions, the primary xylo-products suffered a partial epimerization at C(α) to yield mixtures containing the corresponding lyxo-products ( b -series): The equilibrium between the xylo- and lyxo-isomers was estimated for 5a/5b =1:3, 12a/12b =5:2, 13a/13b =3:1, and 16a/16b =2:1. Since the stereoisomers of the a - and the b -series were always separable, the other lyxo-products, i.e. 6b , 7b , could be prepared from 5b and 12b .     

Electronic structure and conformational properties of the amide linkage Part 5. Internal rotation and inversion in 1-formylaziridine

Internal rotation and nitrogen inversion in 1-formylaziridine (1) have been investigated by quantum mechanical (ab initio and MNDO) calculations, especially with respect to the variation of the geometry of the aziridine ring. While conformational stability is mainly determined by the n(N)/π(CO) interaction, the bond lengths within the ring are affected by the amount of interaction between the π(CO) orbital and the Walsh orbital ω_A. To separate the two types of interaction, calculations were also performed on formylcyclopropane (9). The torsional potential of 1 has a minimum close to the perpendicular conformation 1b. The two bisected conformations, 1a and 1c, are transition states for internal rotation. For nitrogen inversion, a barrier of 1.44 kcal mol⁻¹ (ab initio) was calculated. Calculations on 1-cyanoaziridine (7) gave inversion barriers of 5.81 (ab initio) and 12.31 kcal mol⁻¹ (MNDO). Probably due to methodical reasons the ab initio values seem to be too low, as calculations with different basis sets for aziridine indicate.     

Reactions of Haloarenes with Thiolate Anions in Tetraglyme: Competition between electron transfer and SNAr mechanisms

The reaction of the bromo-substituted naphthalene 1 with the alkanethiolate anions 2a–b and arenethiolate 2c in tetraglyme gave the corresponding 1-naphythyl thio-ethers 3a–c . Thio-ethers 3a–c were oxidized to the corresponding sulfones 4a–c with m- chloroperoxybenzoic acid. The reaction of the dichloro-substituted anthracene 5a with 2b gave the disubstutution product 6a. The reaction of 9-bromoanthracene 5c with the alkanethiolate 2b gave 6b , whereas the reaction of 5c with the arenethiolate 2c gave a mixture of substitution product 6c and anthracene 7. The observation of the formation of both 6c and 7 is explained by the competition between substitution (S_nAr) and electron-transfer (ET) mechanisms. Consistent with this interpretation, the reaction of the monochloro-substituted 5b , which has a higher-energy σ^* orbital, with 2c gave 6c without the formation of 7. Zn/KOH in tetraglyme was shown to reduce the aryl halides 5b–c and thio-ether 6c to 7 .     

新型胍基葡萄糖苷的合成及生物活性

将2,3,4,6-四-O-乙酰基-β-D-吡喃葡萄糖基异硫氰酸酯(1)与2-氨基-4/6-取代-苯并噻唑(2a~2e)反应, 生成糖基硫脲衍生物(3a~3e), 再在伯胺存在下经氯化汞脱硫, 得到一系列新的多乙酰基胍基糖苷类化合物(4a~4d, 5a~5d, 6a~6d, 7a~7d), 糖基的保护基团在甲醇钠/甲醇条件下脱除. 所有新化合物的结构均经IR, 1H NMR, MS谱和元素分析证实, 所得产物均为β-构型. 生物活性测试结果表明, 化合物4c, 6c, 8b, 8c等对HIV-1蛋白酶表现出了较高的抑制活性; 化合物7c具有抗流感乙型病毒活性; 化合物5e, 7c, 7d等对血管紧张素转化酶具有抑制活性.     

Synthesis and characterization of adducts of p-azidostyrene derivatives to fullerene C_(60)

Fullerene C60 reacted with p-azidostyrene derivatives in refluxing chlorobenzene,yielding monoadducts 2a and 2d as well as diadduct 2c with aziridine structure at 6/6-ring junctions.Experimental results showed that the addition of the second azide to the monoadduct was regioselective.The diadduct,of Cs symmetry in C60 moiety,was unstable by opening to be 1,6-imido[10]annulene structure.     

Synthesis and In Vivo antitumor and antiviral activities of 2′-deoxyribofuranosyl and arabinofuranosyl nucleosides of certain purine-6-sulfenamides,sulfinamides and sulfonamides

2′-Deoxyribofuranosyl and arabinofuranosyl nucleosides of certain purine-6-sulfenamides, sulfinamides and sulfonamides have been prepared by sequential amination and controlled oxidation of the corresponding 6-thiopurine nucleosides, and evaluated for antiviral and antitumor activities in mice. Amination of 2′-deoxy-6-thioinosine ( 4a ) and 9-β-D-arabinofuranosyl-6-thiopurine ( 4c ) with chloramine solution gave the corresponding 6-sulfenamides 5a and 5c , respectively, which on selective oxidation with 3-chloroperoxybenzoic acid (MCPBA) gave diastereomeric 9-(2-deoxy-β-D-erythro-pentofuranosyl)purine-6-sulfinamide ( 6a ) and 9-β-D-arabinofuranosylpurine-6-sulfinamide ( 6c ), respectively. However, oxidation of 5a and 5c with excess of MCPBA gave the corresponding 6-sulfonamide derivatives 7a and 7c , respectively. Similar amination of 2′-deoxy-6-thioguanosine ( 4b ), ara-6-thioguanine ( 4d ) and α-2′-deoxy-6-thioguanosine ( 8 ) gave the respective 6-sulfenamide derivatives 5b, 5d and 9 . Controlled oxidation of 5b, 5d and 9 gave (R,S)-2-amino-9-(2-deoxy-β-D-erythro-pentofuranosyl)purine-6-sulfinamide ( 6b ), (R,S)-2-amino-9-β-D-arabinofuranosylpurine-6-sulfinamide ( 6d ) and the α-anomer of ( 6b) (10 ), respectively. The diastereomeric mixture of (R,S )-10 was partially resolved and the structure of S -10 was assigned by single-crystal X-ray diffraction analysis. Oxidation of 5b, 5d and 9 with excess of MCPBA afforded the respective 6-sulfonamide derivatives 7b, 7d and 11 . Nucleosides 5c and 7c were significantly active against Friend leukemia virus in mice, whereas 6c was somewhat less active. Of the 20 nucleosides evaluated, 12 exhibited biologically significant anti-L1210 activity in mice. Nucleosides 6b and 7a at 173 mg/kg/day × 1 showed a T/C of 153, whereas 7d at 800 mg/kg/day × 1 showed a T/C of 153 against L1210 leukemia. The α-nucleoside 9 at 480 mg/kg/day × 1 gave a T/C of 172. A single treatment with 6b, 7a, 7d and 9 reduced the body burdens of viable L1210 cells by more than 99.2%. The antileukemic activity of these novel nucleosides tended to parallel solubility.     

Chemical and electrochemical oxidation of thiophene-pyridine and thiophene-pyrimidine co-oligomers in solutions

Chemical and electrochemical oxidation (or p-doping) of three types of pi-conjugated co-oligomers, Py-Th-(Th)n-Th-Py (Py = pyridine unit; Th = thiophene unit; 5a, n = 1; 6a, n = 2), Th-Py-(Th)n-Py-Th (5b: n = 1; 6b: n = 2), and Pym-Th-(Th)n-Th-Pym (Pym = pyrimidine unit; 5c: n = 1; 6c: n = 2), in solution systems has been studied. The chemical oxidation with NOBF(4) proceeded with isosbestic points in the UV-vis spectrum. The UV-vis absorption peak of 5a at 418 nm in CH(2)Cl(2) shifted to 456 nm after oxidation of 5a with NOBF(4). The oxidized 5a was easily reduced by N(2)H(4) to give the original UV-vis spectrum of 5a, and 5b, 6b, and 5c behaved similarly in the oxidation and reduction. In the oxidation by NOBF4, an (oxidized co-oligomer)/(original neutral co-oligomer) ratio of 1 was attained at [NOBF4] = 1.3 x 10(-6), 4 x 10(-6), 7 x 10(-6), and 9 x 10(-6) M for 5a, 6b, 5b, and 5c, respectively. The obtained data are considered to reflect the ease of oxidation of the co-oligomer, which is affected by the electron-accepting nature of the N-containing aromatic unit in the co-oligomer and effective pi-conjugated length of the co-oligomer. The cyclic voltammogram of 5a showed three redox couples with anodic peak current potentials of Epa = 0.75, 1.10, and 1.34 V versus Ag+/Ag, respectively. The first oxidation peak was assigned to one-electron oxidation of 5a, and electronic current of the first anodic peak (i) of 5a and 5c was proportional to (scanning rate)1/2. From the i- (scanning rate)1/2 relationship, diffusion constants, D's, of 5a and 5c were estimated to be 9.6 x 10(-6) and 1.7 x 10(-5) cm2 s(-1), respectively. CV data of 5b with the terminal thiophene units indicated occurrence of electrochemical oxidative polymerization of 5b.