Graphical Abstract The front cover picture is an artistic illustration of gold associated with HFIP, represented by a golden ball surrounded with a banner. This Au/HFIP duo efficiently transformed alkynylnaphthaldehydes to major trans tricyclic derivatives, according to a 6-enolendo-exo-trig pathway. Scope and limitations as well as mechanistic studies for this rearrangement process were described leading to tricyclic functionalized ketones. Details can be found in the Communication by Véronique Michelet and co-workers (A. Truchon, A. Dupeux, S. Olivero, V. Michelet, Adv. Synth. Catal. 2023, 365, XXXX–XXXX; DOI: 10.1002/adsc.202201387)
Substituent effects on the electrophotographic properties of N,N,N′,N′-tetraarylphenylenediamines 1a—i derivatives have been investigated to obtain a molecular design guide to enhance photosensitivity of hole transporting materials for organic photoreceptors. The introduction of methyl groups into N-substituted phenyl moiety in all the cases increases considerably the photosensitivity and reduc—es the residual potential, moreover, the m- and p-substitution was found to be the most promising. On the other hand, the presence of alkyl substituents enhances the stability of glassy state of such low molecular weight organic compounds.
A palladium-catalyzed cross-coupling reaction between the arylstannane 5c and the bicyclic vinyl bromide 3, which was obtained by a Diels—Alder reaction, provided the substituted bicyclo[2.2.2]octa-2,5-diene 6. A subsequent ozonolysis of the less substituted double bond of 6 followed by reduction of the intermediate with sodium borohydride provided the highly functionalized cyclohexene 8. This compound can be viewed as a substructure of the antitumor antibiotic dynemicin A.
Routes to diastereomers of constrained 4-amino-piperidines — a common pharmaceutically used diaminic building block — are realized mainly on the basis of CN-double bond species or their radicalic or anionic analogues. Kinetically controlled reactions on the one hand and thermodynamic control of reactions, reversible introduction of a repulsive group, direction of a reactant by intramolecular complexation, or involvement of radicalic or anionic intermediates with strong isomerization tendency on the other hand are the tools for a complementary accessibility of both diastereomers.
(±)-Fenvaleric acid 2, the key intermediate for the preparation of the pesticide esfenvalerate 1, was prepared by a novel sequence which first involves the Henry reaction of 2-methyl-1-nitropropane and 4-chlorobenzaldehyde. The nitroaldol reaction provided nitroalcohol 5 which was then reduced to the corresponding aminoalcohol 6. Submission of 6 to an aminopinacol rearrangement promoted by nitrous acid deamination then afforded aldehyde 8 through a 1,2-aryl shift. The product fenvaleric aldehyde 8 was then converted to the title compound 2 by a modified Jones oxidation.
Phenazine and the dicarboxylic acids fumaric-, 2,3- dihydroxyfumaric-, and oxalic acid form 1 : 1 cocrystals. X-ray analysis shows that the molecules are arranged as linear tapes, mainly held together by strong O-H…︁N and weak C(sp 2)-H…︁O hydrogen bonds. Individual molecules form staples which are surrounded by staples of the other molecules. The angle between neighbouring tapes varies from ca. 90° in the cocrystal of phenazine and fumaric acid to ca. 70° in the co-crystal of phenazine and 2,3-dihydroxyfumaric acid, and ca. 25° in the cocrystal of phenazine and oxalic acid. The molecules assume an offset face-to-face arrangement in individual phenazine staples. Negligible π-stacking is observed in the cocrystals of phenazine with fumaric- and 2,3-dihydroxyfumaric acid. The absence of the CC double bond as spacer in oxalic acid leads to appreciable π-overlap of phenazine molecules in the cocrystal. As a consequence, the latter cocrystal displays special properties. An irreversible lightinduced electron transfer generates initially singlet and triplet biradicals with the unpaired electrons positioned on neighbouring phenazine molecules. Partially, the electrons are transformed to magnetically independent electrons which show strong exchange narrowing in the e.p.r. spectrum at temperatures > 0 °C. The proposed model is supported by UV/Vis-e. s.r.-, and SQUID measurements.
A new efficient method for the stereoselective preparation of trans-2,5-bis(alkyloxymethyl)pyrrolidines (7) using easily available starting materials is described. The main step of this synthesis is the stereoselective formation of the pyrrolidine ring by the 1,3-dipolar cycloaddition reaction of an in situ generated azomethine ylide. Both enantiomers of the C-2-symmetric auxiliaries are prepared separately in a short reaction sequence.
The aqueous solubilities (logS) of a set of 27 5-amino-1-aryl- 1H-tetrazoles with known biological activity were determined photometrically and correlated with their octan-1-ol/water partition coefficients (logP). The otained Linear relationship between logS and logP can be significantly improved by a melting point term, an electronic term and several indicator variables describing the deviating solubility behaviour of compounds with hydrogen bonding groups and the dependence on substituent position. The calculated more-parameter equations allow the reliable prediction of aqueous solubilities for 5-amino-1-aryl-1H-tetrazoles not yet synthesized or investigated.
Ten halogenated lunularins 16, 17, 26, 27, 30, 31, 36, 37, 42 and 43 as model substances for a new class of halometabolites isolated from bryophytes are prepared by chemical total syntheses according to a Wittig-protocol using halogenated aldehydes and phosphonium salts and/or by an in vitro halogenation of lunularin using potassium halide and hydrogen peroxide in the presence of a chloroperoxidase. The results confirm the need for a haloperoxidase in the in vitro chlorination of lunularin 6.
The design and synthesis of new materials are two key steps in the advancement of technology. One of the most promising approaches of development of new materials that combine advantages of organic polymers with those of inorganic solids is to devise polymers that have a backbone of inorganic atoms to which are attached organic side groups. Among the best developed examples of „ inorganic organic polymers„ are organosilicon polymers. The synthesis of new organosilicon polymers using silyl triflate intermediates is reviewed in this article. Protodephenylation of phenylated polysilanes as well as poly(silylenemethylenes) by triflic acid gave new functionalized compounds 12—25, 27—39. Network polymers were obtained by reductive coupling of silyl triflates with potassium-graphite. Novel poly(silylenealkynes) 51—67 and poly(silylenearylenes) 68—91 containing a regular alternating arrangement of silylene groups and organic units were prepared from α, ω-bis[(trifluoromethyl)sulfonyloxysilyl]-substituted compounds and dinucleophiles. Some of the polymers are potential organic precursor for ceramic materials. The correlation between structure and thermolytic behaviour is demonstrated on selected examples.
The classical Mannich reaction of aromatic methyl ketones with paraformaldehyde and dimethylamine hydrochloride resp. dimethyl(methylene)ammonium chloride has been extended to a few cases of 1-aryl-2-dimethylaminomethyl-prop-2-en-1-ones (ADMP reagents). They have gained remarkable attention in medicinal chemistry, but only more recently their properties as valuable building blocks for ring closure reactions to form either aroyl or dimethylaminomethyl substituted heterocyclic compounds has been evaluated. In this review, a collection of representative examples for their preparation (Scheme 2) and biological effects as well as the synthetic potential for the synthesis of heterocycles (Scheme 3—8) is given. The reaction of 4-hydroxycoumarin delivers with ADMP reagents, via the formation of detectable 3-(2-benzoylallyl)-4-hydroxycoumarins as secondary substitution products, after ring closure 3-benzoyl-3,4-dihy-dro-2H,5H-1-benzopyrano[4,3-b]pyran-5-ones (Scheme 4). The reaction of 4-hydroxy-6-methylpyran-2-one with ADMP reagents is investigated systematically in order to assess its suitability in carbon—carbon bond forming reactions as well as to provide the conditions for subsequent ring closure or intermolecular addition of further nucleophiles to the enone double bond of the intermediate 3-(2-benzoylallyl)-4-hy-droxy-6-methylpyran-2-ones yielding miscellaneous 3-substituted 2-pyrones (Scheme 5 and 8), and their application as building blocks for the combinatorial chemistry. The condensation of ADMP reagents with 2-aminopyridines gives rise to 3-benzoyl-3,4-dihydro-2H-pyrido[1,2-a]pyrimidines (Scheme 6) and the corresponding reaction using amidines affords 5-benzoyl-1,4,5,6-tetrahydropyrimidines (Scheme 7).
Four different disulfides, [2,2′-dithiobis-(2-mercaptoacetophenone)]-4-triphenylmethylthiosemicarbazone (1), [5,5′-dithiobis-(4-formyl-3-methyl-1-phenylpyrazole)]-4-triphenylmethylthiosemicarbazone (2), bis[1-(2-mercaptophenyl)-2-(4-(1-phenyl-3-methyl)pyrazole)-azaethene]di-sulfide (3) and bis[1-phenyl-2-(4-(1-phenyl-3-methyl-5-mercapto) pyrazole)-azaethene]disulfide (4) were synthesized by Schiff base reactions. Their electrochemical behaviour was examined by cyclic voltammetry. The results show low potentials for the disulfide reduction so that these compounds are suitable for the syntheses of tridentate thiolate ligands from disulfides by electrochemical cleavage. In addition compounds 2 and 4 were characterized by X-ray structure determination. The structures show significant differences of the S—S bonds and angles as compared to other disulfides without bulky substituents.
In a multistep process, anthracenide and both 1-benzoyl-2-methyl-3-phenylaziridines 1a form carbanion 4a that abstracts a proton from the solvent THF. The steep N pyramid of cis-1a makes attack of 4a on C=O of cis-1a fast enough to compete with proton abstraction while C=O of trans-1a with its flat and rapidly inverting pyramid did not react with 4a. The initially generated ketyls of 1a show another cis-trans effect of steric repulsion: their homolytic ring opening forms benzylic radical 3a, the precursor of carbanion 4a, but this opening is regiospecific for the cis ketyl only. The trans ketyl forms some isomeric radical too.
Starting from 2,5-bisbenzyloxy-4-methyl-benzaldehyd 2-(3-amino-2-acetyl-but-2-enyl)-5-methyl[1,4]benzoquinones 9a—e are synthesized as model compounds in order to study the ambident reactivity of enaminones and quinones. Spontaneus cyclization of 9b—e in ethanol or acetic acid to 1-aza-spiro[4,5]deca-2,7-dien-6,9-dion 20b—e in good yield is observed. 6-Hydroxy-3-acetyl-quinoline 21 is obtained from 9a. In one case (9c) 2-acetyl-3-benzylamino-7-hydroxy-naphthalene (17) was formed as by-product. 9d in alkoholic perchloric acid leads to quinolinium salt 18 in low yield.
The title compounds were synthesized by 1,3-dipolar cycloaddition of 3,3,3-trifluoropropinyl benzene (2) to the azido sugars 2,3,4,6-tetra-O-acetyl-β-D-galactopyranosyl azide (1), 6-O-acetyl-4-O-cyclohexylcarbamoyl-2,3-O-(2,2,2-trichloroethylidene)-β-D-gulopyranosyl azide (6), 6-azido-6-deoxy-1,2:3,4-di-O-isopropylidene-α-D-galactopyranose (12), and methyl 6-azido-4-O-cyclohexylcarbamoyl-6-deoxy-2,3-O-(2,2,2-trichloroethylidene)-β-D-gulopyranoside (16), respectively. Because of the dissymmetry of the dipolarophile 2, always two regioisomeric products were obtained, the nucleoside-analogous compounds 3/4 (from 1) and 7/8 (from 6), respectively, and the reversed nucleosides 13/14 (from 12) and 17/18 (from 16), respectively. Protecting group chemistry like transesterification, deacetalation, hydrodechlorination is demonstrated in some cases. Thus, the trichloroethylidene derivatives 7, 8, 17, and 18 were converted into the corresponding ethylidene derivatives (9, 10, 19, 20) by treatment with tributylstannane/AIBN. An X-ray analysis is given for the 1-(2,3,4,6-tetra-O-acetyl-β-D-galactopyranosyl)-4-trifluoromethyl-5-phenyl-1,2,3-triazole (4) and for the 1-[6-O-acetyl-4-O-cyclohexylcarbamoyl-2,3-O-(2,2,2-trichloroethylidene)-β-D-gulopyranosyl]-4-trifluoromethyl-5-phenyl-1,2,3-triazole (7).
Somatostatin octapeptide analogues of the general sequence DPhe5-Phe 6-Tyr7-DTrp8-Lys9-Val10-Ph 11-Thr12-NH2 containing two types of backbone cyclization have been synthesized by the solid phase methodology. Backbone cyclization in these peptides was achieved via N-modified phenylalanines in position 6 and 11. The N-modified amino acids were incorporated as dipeptide building units which have been prepared in solution prior to the solid phase synthesis. Two dipeptide units of structure a) Fmoc-aa 1 ψ[CO—N((CH2)n-X)]Phe—OH or b) Fmoc-aa1 ψ[CH2—N(COlpar;CH2)n-X)]Phe—OH have been introduced into the peptide sequence. Different resins and linkers were examined for an optimized peptide assembly and monitoring. The synthesized somatostatin analogues are highly resistant against enzymatic degradation as determined in vitro by incubation with rat liver homogenate. The biological activity was determined in binding experiments to the somatostatin receptors expressed in CHO- or BON-1 cells. Most analogues show moderate activity without differentiation between the receptor subtypes.
The influence of substitution on the absorption and Luminescence spectra of oligo(phenylenevinylene)s has been studied using distyrylbenzene (DSB) as a model compound. The degree, character, and pattern of substitution was varied systematically, altering the electronic properties of the DSB, the wavelength of the emitted light could be tuned over a range of 100 nm. The syntheses of 6b—h were performed by twofold Wittig Horner-olefinations of bisphoshonates 1a, b with substituted benzaldehydes 2a—i, 6i via Heck-reaction of the dibromosulfonylbenzene 3, 6k by Siegrist-reaction of 4 with N-phenylbenzaldimine and the Knoevenagel-reaction of benzyl cyanide with 5 led to 6l.
We introduce a systematic nomenclature for mechanically linked molecules - such as catenanes, rotaxanes, and assemblies derived from these structural elements - which comes up to the increasing complexity of already synthesized interlocked molecules and the ones to be expected in future. Like in the naming of other substance classes (polycycles, phanes, crown compounds, podands, dendrimers) we attach importance to the fact, that certain units in the name, e.g. expressions in brackets, quickly convey an idea of the molecular architecture. Furthermore, this modular nomenclature reveals as many analogies to the IUPAC nomenclature as possible.
Journal für praktische ChemieVolume 342, Issue 3 p. 316-321 Reagent Copper(II) Triflate in Organic Synthesis Christian Hertweck Dr., Christian Hertweck Dr. hertweckcommat;u.washington.edu Search for more papers by this author Christian Hertweck Dr., Christian Hertweck Dr. hertweckcommat;u.washington.edu Search for more papers by this author First published: 03 April 2000 https://doi.org/10.1002/(SICI)1521-3897(200003)342:3<316::AID-PRAC316>3.0.CO;2-SCitations: 18AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Citing Literature Volume342, Issue3March 2000Pages 316-321 RelatedInformation
Journal für praktische ChemieVolume 342, Issue 7 p. 666-674 Full Paper Heterobimetallische Komplexe des Bors und Aluminiums mit dem 2-Dimethylaminomethyl)ferrocenyl-Liganden: Synthesen, Charakteristika und Kristallstrukturen Frank Voigt, Frank Voigt Merseburg, Martin-Luther-Universität Halle-Wittenberg, Institut für Anorganische ChemieSearch for more papers by this authorKlaus Jacob Prof. Dr., Corresponding Author Klaus Jacob Prof. Dr. jacobcommat;chemie.uni-halle.de Merseburg, Martin-Luther-Universität Halle-Wittenberg, Institut für Anorganische ChemieFachbereich Chemie, Institut für Anorganische Chemie, Martin-Luther-Universität Halle-Wittenberg, Standort Merseburg, Geusaer Straße, D-06217 Merseburg, Fax: Internat. code (0) 3461 46 2002Search for more papers by this authorNaka Seidel, Naka Seidel Merseburg, Martin-Luther-Universität Halle-Wittenberg, Institut für Anorganische ChemieSearch for more papers by this authorAxel Fischer, Axel Fischer Magdeburg, Otto-von-Guericke-Universität, Chemisches InstitutSearch for more papers by this authorClaus Pietzsch, Claus Pietzsch Freiberg, Technische Universität Bergakademie Freiberg, Institut für Angewandte PhysikSearch for more papers by this authorPiero Zanello, Piero Zanello Siena/Italy, Universita dell' Siena, Dipartimento di ChimicaSearch for more papers by this author Frank Voigt, Frank Voigt Merseburg, Martin-Luther-Universität Halle-Wittenberg, Institut für Anorganische ChemieSearch for more papers by this authorKlaus Jacob Prof. Dr., Corresponding Author Klaus Jacob Prof. Dr. jacobcommat;chemie.uni-halle.de Merseburg, Martin-Luther-Universität Halle-Wittenberg, Institut für Anorganische ChemieFachbereich Chemie, Institut für Anorganische Chemie, Martin-Luther-Universität Halle-Wittenberg, Standort Merseburg, Geusaer Straße, D-06217 Merseburg, Fax: Internat. code (0) 3461 46 2002Search for more papers by this authorNaka Seidel, Naka Seidel Merseburg, Martin-Luther-Universität Halle-Wittenberg, Institut für Anorganische ChemieSearch for more papers by this authorAxel Fischer, Axel Fischer Magdeburg, Otto-von-Guericke-Universität, Chemisches InstitutSearch for more papers by this authorClaus Pietzsch, Claus Pietzsch Freiberg, Technische Universität Bergakademie Freiberg, Institut für Angewandte PhysikSearch for more papers by this authorPiero Zanello, Piero Zanello Siena/Italy, Universita dell' Siena, Dipartimento di ChimicaSearch for more papers by this author First published: 17 August 2000 https://doi.org/10.1002/1521-3897(200009)342:7<666::AID-PRAC666>3.0.CO;2-NCitations: 9AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onEmailFacebookTwitterLinkedInRedditWechat Abstract Heterobimetallic Complexes of the Boron and Aluminum Containing 2-(Dimethylaminomethyl)ferrocenyl Ligands: Syntheses, Characteristics and Structures The organometal derivatives (FcN)BCl2 (1), (FcN)2AlX [X = Br (2), I (3)] are formed at metathesis reactions of the anhydrous metal halides MX3 (M = B, X = Cl; M = Al, X = Br, I) with 2-(dimethylaminomethyl)ferrocenyl lithium, (FcN)Li. In contrary donor-acceptor complexes of the formula L → BX′3 [X′ = C6H5CH2 (4), Cl (5), Br (6), I (7)] are formed at metalation reactions of dimethylaminomethylferrocene (L, FcNH) and BX′3.The crystal structures of 1-3 and 5 could be proved by single crystal x-ray determinations. An intervalent electron transfer was determined by 57Fe-Mössbauer spectroscopy at 1-7. Cyclic voltammetric measurement was carried out at complex 4. REFERENCES 1 K.Jacob, F. T.Edelmann, J. prakt. 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A.Fischer, J. Organomet. Chem. 1997, 545, 543. 17 Th.Gelbrich, U.Dümichen, J.Sieler, Acta Crystallogr. 1999, SectionC 55, 1797. 18 J.Azizian, R.M.G.Roberts, J.Silver, J. Organomet. Chem. 1986, 303, 397. 19 K.Jacob, J.Scholz, K.Merzweiler, C.Pietzsch, J. Organomet. Chem. 1997, 527, 109. 20 K.-H.Thiele, R.Kurzhals, U.Dümichen, Z. anorg. allg. Chem. 1995, 621, 97. 21 C.Pietzsch, A.Kirsten, K.Jacob, F. T.Edelmann, Z. Phys.Chem. 1998, 205, 271. 22 K. Goldanskii, R. Herber (Eds.): Chemical Application of Mößbauer Spectroscopy, Academic Press New York, N.Y., 1968, p.29 23 A.Togni, M.Hobi, G.Rihs, G.Rist, A.Albinati, P.Zanello, D.Zech, H.Keller, Organometallics 1994, 13, 1224. 24 R.Köster, G.Bruno, Liebigs Ann. Chem. 1960, 629, 89. 25 G. M. Sheldrick, SHELXL-97. A program for crystal structure refinement, Universität Göttingen 1997 Citing Literature Volume342, Issue7September 2000Pages 666-674 ReferencesRelatedInformation
