Polyelectrolytes in a Historic Setting

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State‐of‐the‐Art and Future of Combinatorial Polymer Research: 2nd DPI Workshop on Automated Synthesis and High‐Throughput Experimentation in Polymer and Materials Research

This section contains reports on topical conferences. Reports are usually written at the request of the editorial office, but unsolicited contributions are also welcome. Suggestions should be sent to the editorial office of the Macromolecular journals, preferably by E‐mail to macromol@wiley‐vch.de.     

Ink‐Jet Printing of Functional Polymers and Materials: First International Workshop in Eindhoven

This section contains reports on topical conferences. Reports are usually written at the request of the editorial office, but unsolicited contributions are also welcome. Suggestions should be sent to the editorial office of the Macromolecular journals, preferably by E‐mail to macromol@wiley‐vch.de.     

Inkjet Printing of Functional Polymers and Materials: 2nd International Workshop in Eindhoven

This section contains reports on topical conferences. Reports are usually written at the request of the editorial office, but unsolicited contributions are also welcome. Suggestions should be sent to the editorial office of the Macromolecular journals, preferably by E‐mail to macromol@wiley‐vch.de.     

Bayer Symposium on High‐Throughput Experimentation in Materials Research and Process Optimization

This section contains reports on topical conferences. Reports are usually written at the request of the editorial office, but unsolicited contributions are also welcome. Suggestions should be sent to the editorial office of the Macromolecular journals, preferably by E‐mail to macromol@wiley‐vch.de.     

New Challenges in Combinatorial Polymer Research: 3rd DPI Workshop on Automated Synthesis and High‐Throughput Experimentation in Polymer and Materials Research at the Eindhoven University of Technology

Conference Reports: This section contains reports on topical conferences. Reports are usually written at the request of the editorial office, but unsolicited contributions are also welcome. Suggestions should be sent to the editorial office of the Macromolecular journals, preferably by E‐mail to macromol@wiley‐vch.de.     

Hermann Staudinger Award 2006

Macromolecular News: This section contains news of the macromolecular community all over the world. Articles about, for example, people, projects, and market trends are welcome. Suggestions should be sent to the editorial office of the Macromolecular journals, preferably by E-mail to macromol@wiley-vch.de. The editorial office decides which articles will be published.     

Cover Picture: Journal of the Chinese Chemical Society 2/2013

This paper entitled Development of the Ireland–Claisen Rearrangement of Allyl‐2‐alkoxyacetate Bearing an Allylic Amine and the Transformation to 3‐hydroxy‐4‐hydroxy‐methylpyrrolidine was awarded Best Article Award in 2012. The authors gratefully acknowledge the National Science Council, in support of this research. A special acknowledgment also goes to the editorial and reviewers for their supporting in awarding our paper as one of the Best Articles in 2012. Noteworthily, the honor should belong to late Professor Yung‐Son Hon, as his initiative thoughts and extraordinary dedication went a long way in influencing the ideas in this article. For more information on this article, turn to J. Chin. Chem. Soc. 2012 , 59 (3), 273‐282.     

Elementary Dr. Watson

J. D. Watson in his book, The Double Helix, blamed J. N. Davidson’s text The biochemistry of nucleic acids for Watson initially using the wrong formulae of the nitrogenous bases in his and F. Crick’s quest for the DNA structure. A closer look at Davidson’s text, however, reveals that most of the structures were correctly drawn the only exception being guanosine represented in the enol form.     

Oxazolochlorins. 14.

The structure of 8‐oxo‐5,10,15,20‐tetraphenyl‐7‐oxaporphyrin N²⁴‐oxide, C₄₃H₂₈N₄O₃, (4B), shows that N‐oxidation of the pyrrole opposite the oxazolidone group cants the pyrrole out of the mean plane of the chromophore. This also affects the oxazolidone group, which is also slightly canted out. This conformation is qualitatively similar to that of the parent meso‐tetraphenylporphyrin N‐oxide, but dissimilar to that of the porpholactone N‐oxide isomer 8‐oxo‐5,10,15,20‐tetraphenyl‐7‐oxaporphyrin N²²‐oxide, (4A), carrying the N‐oxide at the oxazolidone group. While the degree of canting of the N‐oxidized groups in both cases is comparable (and more pronounced than in the porphyrin N‐oxide case), in (4A) the pyrrolic groups adjacent to the N‐oxidized group are more affected than the opposing group. These differences in the conformational modes may contribute to rationalizing the distinctly different electronic properties of (4A) and (4B).     

Azole. 45.

The three title compounds, namely (Z)‐1‐(4,5‐di­nitro­imidazol‐1‐yl)‐3‐morpholinopropan‐2‐one 2,4‐di­nitro­phenyl­hydrazone, C₁₆H₁₇N₉O₉, (IV), (Z)‐3‐morpholino‐1‐(4‐morpholino‐5‐nitro­imidazol‐1‐yl)propan‐2‐one 2,4‐di­nitro­phenyl­hydrazone, C₂₀H₂₅N₉O₈, (Va), and (E)‐3‐morpholino‐1‐(4‐morpholino‐5‐nitro­imidazol‐1‐yl)propan‐2‐one 2,4‐di­nitro­phenylhydra­zone tetra­hydro­furan solvate, C₂₀H₂₅N₉O₈·C₄H₈O, (Vb), have been prepared and their structures determined. In (IV), the C‐4 nitro group is nearly perpendicular to the imidazole ring and the C‐4—NO₂ bond length is comparable to the value for a normal single Csp²—NO₂ bond. In (IV), (Va) and (Vb), the C‐­5 nitro group deviates insignificantly from the imidazole plane and the C‐5—NO₂ bond length is far shorter in all three compounds than C‐4—NO₂ in (IV). In consequence, the C‐4 nitro group in (IV) is easily replaced by morpholine, while the C‐5 nitro group in (IV), (Va) and (Vb) shows an extraordinary stability on treatment with the amine. The E configuration in (Vb) is stabilized by a three‐centre hydrogen bond.     

Two new acylated flavonoid glycosides from Morina nepalensis var. alba Hand.‐Mazz.

From the whole plant of Morina nepalensis var. alba Hand.‐Mazz., two new acylated flavonoid glycosides ( 1 and 2 ), together with four known flavonoid glycosides ( 3–6 ), were isolated. Their structures were determined to be quercetin 3‐O‐[2″′‐O‐(E)‐caffeoyl]‐α‐L ‐arabinopyranosyl‐(1→6)‐β‐D ‐galactopyranoside (monepalin A, 1 ), quercetin 3‐O‐[2″′‐O‐(E)‐caffeoyl]‐α‐L ‐arabinopyranosyl‐(1→6)‐β‐D ‐glucopyranoside (monepalin B, 2 ), quercetin 3‐O‐α‐L ‐arabinopyranosyl‐(1→6)‐β‐D ‐galactopyranoside (rumarin, 3 ), quercetin 3‐O‐β‐D ‐galactopyranoside ( 4 ), quercetin 3‐O‐β‐D ‐glucopyranoside ( 5 ) and apigenin 4^′‐O‐β‐D ‐glucopyranoside ( 6 ). Their structures were determined on the basis of chemical and spectroscopic evidence. Complete assignments of the ¹H and ¹³C NMR spectra of all compounds were achieved from the 2D NMR spectra, including H–H COSY, HMQC, HMBC and 2D HMQC‐TOCSY spectra. Copyright © 2002 John Wiley & Sons, Ltd.     

Pteridines. Part CXIX.

A variety of pyrimidine precursors 12 – 25 were converted into a series of new 7‐hydroxylumazines (=7‐hydroxypteridine‐2,4(1H,3H)‐diones) 26 – 35 which functioned as starting materials for the transformation into the corresponding 7‐chlorolumazines 36 – 45 . Subsequent reaction with hydrazine led to the 7‐hydrazinolumazines 46 – 55 which gave on nitrosation the 7‐azidolumazines 1 and 56 – 64 . These compounds were subjected to short heating in xylene whereby 1 and 56 – 61 showed a new pteridine–purine interconversion in forming a new type of 1,3‐disubstituted or 3‐substituted xanthin‐8‐amine‐derived nitrilium ylides (2,3,6,7‐tetrahydro‐N‐methylidyne‐2,6‐dioxo‐1H‐purin‐8‐aminium ylides) 11 and 65 – 70 . The presence of an additional 6‐alkyl substituent in the 7‐azidolumazines 63 and 64 or of an unsubstituted N(3) position in 62 caused further rearrangement to xanthine‐9‐carbonitriles 71 – 73 . Prolonged heating of 7‐azido‐1,3‐dimethyllumazine ( 1 ) also afforded theophylline‐9‐carbonitrile (=1,2,3,6‐tetrahydro‐1,3‐dimethyl‐2,6‐dioxo‐9H‐purine‐9‐carbonitrile; 5 ). The nitrilium ylide function was established by NMR and UV spectra as well as by elemental analyses. Confirmation of the nitrilium ylide structures was suggested by the result of the heating of 1,3‐dimethyl‐N‐methylidynexanthin‐8‐aminium ylide 11 in EtOH or of 1 in pentan‐1‐ol leading to 8‐aminotheophylline (=8‐amino‐3,7‐dihydro‐1,3‐dimethyl‐1H‐purin‐2,6‐dione; 74 ).     

Nucleotides. Part LXXIII

The (2‐cyano‐1‐phenylethoxy)carbonyl (2c1peoc) group was developed as a new base‐labile protecting group for the 5′‐OH function in solid‐phase synthesis of oligoribonucleotides via the phosphoramidite approach. The half‐lives of its β‐elimination process by 0.1M DBU (1,8‐diazabicyclo[5.4.0]undec‐7‐ene) were determined to be 7–14 s by HPLC investigations. The 2′‐OH function was protected with the acid‐labile tetrahydro‐4‐methoxy‐2H‐pyran‐4‐yl (thmp) group, while the 2‐(4‐nitrophenyl)ethyl (npe) and 2‐(4‐nitrophenyl)ethoxycarbonyl (npeoc) groups were used for the protection of the base and phosphate moieties. The syntheses of the monomeric building blocks, both phosphoramidites and nucleoside‐functionalized supports, as well as the build‐up of oligoribonucleotides by means of this approach are described.     

Pteridines. Part CXVII

A series of side chain reactions starting from the 6‐ and 7‐styryl‐substituted 1,3‐dimethyllumazines 1 and 21 as well as from the 6‐ and 7‐[2‐(methoxycarbonyl)ethenyl]‐substituted 1,3‐dimethyllumazine 2 and 22 were performed first by addition of Br₂ to the C?C bond forming the 1′,2′‐dibromo derivatives 3, 4, 24 , and 26 in high yields (Schemes 1 and 3) (lumazine=pteridine‐2,4(1H,3H)‐dione). Treatment of 3 with various nucleophiles gave rise to an unexpected tele‐substitution in 7‐position and elimination of the Br‐atoms generating 7‐alkoxy‐ (see 5 and 6 ), 7‐hydroxy‐ (see 7 ) and 7‐amino‐6‐styryl‐1,3‐dimethyllumazines (see 8 – 11 ) (Scheme 1). On the other hand, 4 underwent, with dilute DBU (1,8‐diazabicyclo[5.4.0]undec‐2‐ene), a normal HBr elimination in the side chain leading to 18 , whereas treatment with MeONa afforded a more severe structural change to 19 . Similarly, 24 and 26 reacted to 27, 32 , and 33 under mild conditions, whereas in boiling NaOMe/MeOH, 24 gave 7‐(2‐dimethoxy‐2‐phenylethyl)‐1,3‐dimethyllumazine ( 30 ) which was hydrolyzed to give 31 (Scheme 3). From the reactions of 4 and 24 with DBU resulted the dark violet substance 20 and 25 , respectively, in which DBU was added to the side chain (Scheme 2). The styryl derivatives 1 and 21 could be converted, by a Sharpless dihydroxylation reaction, into the corresponding stereoisomeric 6‐ and 7‐(1,2‐dihydroxy‐2‐phenylethyl)‐1,3‐dimethyllumazines 34 – 37 (Scheme 4). The dihydroxy compounds 34 and 35 were also acetylated to 38 and 39 which, on catalytic reduction followed by formylation, yielded the diastereoisomer mixtures 40 and 41 . Deacetylation to 42 and 45 allowed the chromatographic separation of the diastereoisomers resulting in the isolation of 43 and 44 as well as 46 and 47 , respectively. Introduction of a 6‐ or 7‐ethynyl side chains proceeded well by a Sonogashira reaction with 6‐ ( 48 ) or 7‐chloro‐1,3‐dimethyllumazine ( 55 ) yielding 49 – 51 and 56 – 58 (Scheme 5). The direction of H₂O addition to the triple bond is depending on the substituents since the 6‐ ( 49 ) and 7‐(phenylethynyl)‐1,3‐dimethyllumazine ( 56 ) showed attack at the 2′‐position yielding 53 and 60 , in contrast to the 6‐ ( 51 ) and 7‐ethynyl‐1,3‐dimethyllumazine ( 58 ) favoring attack at C(1′) and formation of 6‐ ( 52 ) and 7‐acetyl‐1,3‐dimethyllumazine ( 59 ).     

Cyclometallated compounds. XV.

The title complex, tetra‐μ‐acetato‐O:O′‐bis{[μ‐1,4‐bis(2‐­pyridyl­oxy)­phenyl­ene‐N,C²:N′,C⁶]dipalladium(II)} bis­(tri­chloro­methane) dihydrate, [Pd₄(C₁₆H₁₀N₂O₂)₂(C₂H₃O₂)₄]·2CHCl₃·2H₂O, the product of the reaction of 1,4‐bis(2‐pyridyl­oxy)­benzene with palladium acetate, is shown to be a tetranuclear, rather than a polymeric, species. It crystallizes about a centre of inversion and has two doubly cyclo­palladated ligands bridged by four acetate groups. The cyclo­palladated ligand is far from planar in the complex and has the central benzene rings π‐stacked. The chelate rings exist in shallow boat conformations.     

Nucleotides. Part LXXVIII

Several N(‐hydroxyalkyl)‐2,4‐dinitroanilines were transformed into their phosphoramidites (see 5 and 6 in Scheme 1) in view of their use as fluorescence quenchers, and modified 2‐aminobenzamides (see 9, 10, 18 , and 19 in Scheme 1) were applied in model reactions as fluorophors to determine the relative fluorescence quantum yields of the 3′‐Aba and 5′‐Dnp‐3′‐Aba conjugates (Aba=aminobenzamide, Dnp=dinitroaniline). Thymidine was alkylated with N‐(2‐chloroethyl)‐2,4‐dinitroaniline ( 24 ) to give 25 which was further modified to the building blocks 27 and 28 (Scheme 3). The 2‐amino group in 29 was transformed by diazotation into the 2‐fluoroinosine derivative 30 used as starting material for several reactions at the pyrimidine nucleus (→ 31, 33 , and 35 ; Scheme 4). The 3′,5′‐di‐O‐acetyl‐2′‐deoxy‐N²‐[(dimethylamino)methylene]guanosine ( 37 ) was alkylated with methyl and ethyl iodide preferentially at N(1) to 43 and 44 , and similarly reacted N‐(2‐chloroethyl)‐2,4‐dinitroaniline ( 24 ) to 38 and the N‐(2‐iodoethyl)‐N‐methyl analog 50 to 53 (Scheme 5). The 2′‐deoxyguanosine derivative 53 was transformed into 3′,5′‐di‐O‐acetyl‐2‐fluoro‐1‐{2‐[(2,4‐dinitrophenyl)methylamino]ethyl}inosine ( 54 ; Scheme 5) which reacted with 2,2′‐[ethane‐1,2‐diylbis(oxy)]bis[ethanamine] to modify the 2‐position with an amino spacer resulting in 56 (Scheme 6). Attachment of the fluorescein moiety 55 at 56 via a urea linkage led to the doubly labeled 2′‐deoxyguanosine derivative 57 (Scheme 6). Dimethoxytritylation to 58 and further reaction to the 3′‐succinate 59 and 3′‐phosphoramidite 60 afforded the common building blocks for the oligonucleotide synthesis (Scheme 6). Similarly, 30 reacted with N‐(2‐aminoethyl)‐2,4‐dinitroaniline ( 61 ) thus attaching the quencher at the 2‐position to yield 62 (Scheme 7). The amino spacer was again attached at the same site via a urea bridge to form 64 . The labeling of 64 with the fluorescein derivative 55 was straigthforward giving 65 . and dimethoxytritylation to 66 and further phosphitylation to 67 followed known procedures (Scheme 7). Several oligo‐2′‐deoxynucleotides containing the doubly labeled 2′‐deoxyguanosines at various positions of the chain were formed in a DNA synthesizer, and their fluorescence properties and the T_ms in comparison to their parent duplexes were measured (Tables 1–5).     

Redox Behavior of Anthocyanins Present in Vitis vinifera L.

Voltammetric techniques were employed to study the electrochemical behavior of several anthocyanins. The redox behavior of anthocyanins with the same basic structure, the influence of glycosylation on the redox behavior of anthocyanins derived from different anthocyanidins, and the influence of methoxylation were investigated. The anthocyanins used in this study were malvidin‐3‐O‐glucoside chloride, malvidin‐3,5‐di‐O‐glucoside chloride, cyanidin‐3‐O‐glucoside chloride, cyanidin‐3,5‐di‐O‐glucoside chloride, peonidin‐3‐O‐glucoside chloride, delphinidin‐3‐O‐glucoside chloride and the anthocyanidin petunidin chloride, all of them present in Vitis vinifera L. All hydroxyl groups of the anthocyanins can be electrochemically oxidized and the anthocyanins studied revealed a complex and pH dependent oxidation process, with the occurrence of adsorption and of oxidation products blocking the electrode surface.     

Nucleotides. Part LXXI

A new labelling technique attaching fluorescein via a carbamoyl linker directly to the amino groups of the nucleobases was developed. The amino groups were first converted to the phenoxycarbonyl derivatives (→ 10, 15, 19, 58 ), which reacted under mild conditions with 5‐aminofluorescein to give the corresponding N‐[(fluorescein‐5‐ylamino)carbonyl] derivatives (→ 11 – 14, 16, 17, 20, 59, 60 ). The introduction of the 5‐aminofluorescein residue into properly protected adenylyl‐adenosine dimers (→ 39, 40 ) and trimer (→ 50 ) worked well, and final deprotection of these uniformly blocked precursors led on treatment with DBU (1,8‐diazabicyclo[5.4.0]undec‐7‐ene), in one step to dimer 41 and trimer 51 . Synthesis of an appropriately protected monomeric phosphoramidite building block (→ 75 ) was more difficult, since introduction of the 2‐(4‐nitrophenyl)ethyl residue into the fluorescein moiety in 59 led mainly to trisubstitution to give 61 including the urea function. Formation of the adenylyl dimer 66 and trimer 67 proceeded in the usual manner by phosphoramidite chemistry; however, deprotection of 67 with DBU was incomplete since the O‐alkyl group at the urea moiety was found to be very stable. Finally, the appropriate phosphoramidite building block 75 could be synthesized by the sequence 59 → 72 → 73 → 74 → 75 . The phosphoramidite 75 was used for the synthesis of dimer 77 and trimer 79 by solution chemistry, as well as for that of various oligonucleotides by the machine‐aided approach on solid support carrying the fluorophore at different positions of the chain (→ 84 – 87 ). The attachment of the fluorescein fluorophor via a short carbamoyl linker onto the 6‐amino group of 2′‐deoxyadenosine enables such molecules to function very well in fluorescence‐polarization experiments.     

Cyclopeptide and Terpenoids from Tripterygium wilfordii Hook. f.

The EtOH extract of dried root bark of Tripterygium wilfordii Hook. f. (Celastraceae) afforded a novel macrolactone cyclopeptide named triptotin L (=cyclo[L ‐alanyl‐L ‐alanyl‐3‐(4,4,9‐trimethyldecyl‐3‐hydroxypropanoylglycyl‐L ‐valyl‐L ‐leucyl; 1 ), the new triterpene 2β,6α,22β‐trihydroxy‐24,29‐dinor‐D:A‐friedoolean‐4‐ene‐3,21‐dione named 6α‐hydroxytriptocalline A (=(2β,6α,8α,9β,10α,13α,14β,20β,22β)‐2,6,22‐trihydroxy‐9,13‐dimethyl‐24,25,26,30‐tetranorolean‐4‐ene‐3,21‐dione; 2 ), the new diterpenoid 11,16‐dihydroxy‐14‐methoxy‐18(4→3) abeo‐abieta‐3,8,11,13‐tetraene‐18‐oic acid named 16‐hydroxytriptobenzene H (=(4aS,10aS)‐3,4,4a,9,10,10a‐hexahydro‐5‐hydroxy‐7‐(2‐hydroxy‐1‐methylethyl)‐8‐methoxy‐1,4a‐dimethylphenanthrene‐2‐carboxylic acid; 3 ), and the abietane diterpenoid alkaloid named triptotin J (=(7aS,11aS,11bS)‐7,7a,8,9,10,11,11a,11b‐octahydro‐11b‐hydroxy‐α,α,8,8,11a‐pentamethyl‐6H‐naphth[1,2‐d]azepine‐4‐methanol; 4 ). Their structures were established on the basis of spectroscopic studies.