Synthesis of novel tryptamine and β-carboline derivatives via palladium-catalyzed reaction of bromotryptamine with organic boronic acids

New tryptamine 5, 7 and β-carboline derivatives 3 were preparated by palladium-catalyzed coupling reaction of 5-bromotryptamine 1 with aryl boronic acids. Dedicated to Professor András Lipták on his 70^th birthday.     

Improved synthesis of the enantiomers of propafenone using chiral building blocks

Summary A short and efficient synthesis of the enantiomers of the antiarrhythmic drug propafenone (1) is described using both (R)-isopropylideneglycerol tosylate and (S)-glycidyl tosylate as chiral building blocks. The key step of the high yield synthesis is the acetalization of the carbonyl group in 1-(2-hydroxyphenyl)-3-phenyl-1-propanone (2) which allows application of mild reaction conditions in the subsequent alkylation of the phenolic hydroxy group.With our best wishes dedicated to Prof. Dr.H. Achenbach on the occasion of his 65^th birthday     

Conformational analysis of 2,3-dihydro-2,2-dimethyl-1,4-benzoxazepines and their 1,5-isomers

Summary Conformational analysis of 2,3-dihydro-2,2-dimethyl-1,4-benzoxazepines (1,3,5, and7) and their 1,5-isomers (2,4, and6) was performed by temperature dependent NMR measurements. The effect of substituents on the ring inversion was studied. The results obtained were corroborated by AMl calculations.Dedicated to Prof.Waldemar Adam on the occasion of his 60^th birthday     

Diels-Alder reaction of fulvenes with N-(3,5-dichlorophenyl)-maleimide

Summary N-(3,5-Dichlorophenyl)-maleimide reacts smoothly with a variety of substituted fulvenes (1) to give onlyendo adducts (3) independent of the nature of fulvene substituent,Lewis acid catalyst, and reaction solvent and temperature. The structure of theDiels-Alder adduct3f was determined by X-ray crystallography. Semi-empirical quantum methods (AM1) were used to rationalize theendo stereoselectivity.Dedicated to Professor Fritz Sauter on the occasion of his 65^th birthday     

1,4-Diacyl-3-acylamino-5-aryl-4,5-dihydro-1H-1,2,4-triazoles: Ring closure products of aromatic carbaldehyde (diaminomethylene) hydrazones with acylating agents

Summary Treatment of aromatic carbaldehyde (diaminomethylene)hydrazones1 with hot acetic anhydride or benzoyl chloride affords 1,4-diacyl-3-acylamino-5-aryl-4,5-dihydro-1H-1,2,4-triazoles2. In contrast, a new type of 0,N-acetal with an 1,2,4-triazole substructure (3) is obtained from 4-pyridine-carbaldehyde (diaminomethylene)hydrazone (li) by using a similar reaction procedure. The structures of all novel compounds were confirmed by spectroscopic data (¹H and¹³C NMR, MS, IR); some representative compounds were also studied by X-ray analysis.Dedicated to Professor Dr.S. Makleit on the occasion of his 65^th birthday.     

A new convenient method for the synthesis of 2H‐1,4‐benzoxazine derivatives from nitroketones via intramolecular reductive cyclization

Dedicated to Professor Herbert C. Brown on the occasion of his 90^th birthday. Potentially bioactive 2H‐1,4‐benzoxazine derivatives could be conveniently prepared in one step from the corresponding nitroketones using 10% palladium on carbon with triethylamine in the presence of hydrogen (Pd/C‐TEA‐H₂) system. Several other tertiary amines such as nicotine, pyridine, and quinoline also could be used, but TEA gave the best results.     

Synthesis of 4-isobutyl substituted thiophenes byGewald reaction

Summary TheGewald reaction of 4-methyl-2-pentanone with alkyl cyanoacetates was investigated. Alkyl 2-amino-4-isobutylthiophene-3-carboxylates (4) were formed, together withbis-(2-amino-3-alkoxycarbonyl-4-isobutyl-5-thienyl)-disulfides (5) and alkyl 2-amino-4-isobutyl-5-morpholinothiophene-3-carboxylates (6). The absence of any 4-methyl substituted aminothiophene in the product mixtures came up highly unexpected. The mechanism of the reaction is discussed with respect to previously reported suggestions.Dedicated to Professor Dr.Karl Gewald on the occasion of his 65^th birthday     

The induced circular dichroism of helically shaped racemic bilatrienes

Summary The imperfect mirror image relationship of the circular dichroism of (M) and (P) helical biliverdins bound to a homochiral entity (ICD) has been studied using the kinetically stable racemates (M+P)2 and (M+P)3. The phenomena associated with and eventual implications for the interpretation of ICD spectra of naturally occurring kinetically labile biliverdins in terms of chiral recognition are discussed.Dedicated to ProfessorKarl Schlögl on the occasion of his 70^th birthday     

1,3-Diphenylpropane-1,3-diamines,X: Synthesis and biochemical evaluation of highly substituted 1,3-diphenylpropane-1,3-diamines and preparation of their Pt(II) complexes

Summary The ligands of the title complexes1 and2 were prepared from the pertinent chalcone5 and hydrazine hydrate, followed by N-N cleavage. The estrogenic activity of the diamines11 and12 was determined by measuring the RBA values (calf uterine cytosol) and by a luciferase test in MCF 7-2a cells. The compounds are by far less active thanSchönenberger's most active compound ([meso-1,2-bis(2,6-dichloro-4-hydroxyphenyl)ethane-1,2-diamine]dichloro-platinum(II),3).Dedicated with kind regards to Prof. Dr.G. Seitz, Marburg/Germany, on the occasion of his 60^th birthday     

A new synthesis of thes-triazolo[1,5-a]pyridine ring system

Summary A novel and efficient synthesis ofs-triazolo[1,5-a]pyridines was elaborated by reacting 1,2-diaminopyridinium salts with aldehydes.Dedicated to Prof.F. Sauter on the occasion of his 65^th birthday     

1,3-Diphenylpropan-1,3-diamines IX. reaction of α-chlorooxime ethers with α-lithiobenzylamines

Summary The carbanions of the benzylamine derivatives1–4 have been reacted with -chlorooxime ether5 in order to get precursors of 1,3-diphenylpropane-1,3-diamines. Isonitrile1 afforded the expected result, whereas lithiated benzamide2 underwent oxidative dimerization and transmetallated chlorooxime derivative5. Isoxazolidine3 gave the condensation product21 as a mixture of diastereomers; treatment of imine4 led to the desired amine-oxime15 in low yield.Dedicated with warm regards to Prof. Dr.J. Knabe, Saarbrücken, Germany, on the occasion of his 75^th birthday     

Identification of phenyl-substituted polycyclic aromatic compounds in ring furnace gases using GC-MS and GC-AED

Summary The ring furnace baking process is an intermediate step in the production of graphite electrodes. In this process coal tar pitch is pyrolized to form amorphous carbon and volatile aromatic and polycyclic aromatic compounds (PACs). These gaseous ring furnace emissions were analysed by GC-MS and GC-AED. As a result of the pyrolytic reactions taking place, several phenyl-substituted PACs are generated, which were identified by their chromatographic retention indices and mass spectra. Pure reference compounds were analysed for verification if available. A number of phenyl-PACs are reported to be present in coal tar-related material, including phenylpyridines and phenyldibenzofurans previously unreported. A formation scheme for phenyl-dibenzofurans on the basis of a radical mechanism is proposed. Dedicated to Prof. Dr. Wolfgang Meyer zu Reckendorf, Münster, on the occasion of his 65th birthday. Presented at the 21^st ISC held in Stuttgart, Germany, 15^th–20^th September, 1996     

NMR spectroscopy of organophosphorus compounds II: Stereochemistry of [1-(2H-azirin-2-yl)alkyl]phosphonates

Summary The conformation and relative configuration of [1-(2H-azirin-2-yl)alkyl]phosphonates (2) has been established by thorough investigation of some characteristic representatives of the series by¹H,¹³C,¹⁵N, and³¹P NMR spectroscopy. It is shown that the chemical shift of the proton located to the phosphonate group can be used as a criterion for the discrimination and stereochemical assignment of diastereoisomers. NMR spectroscopic features of the compounds are discussed in terms of structural relationships.Dedicated to Univ.-Prof. Dr.K. Schlögl with the best wishes to his 70^th birthday     

1,3-Diphenylpropane-1,3-diamines XI. Conversion of a 3-hydroxy-1,3-diphenylpropan-1-one to 1,3-diphenylpropane-1,3-diamines

Summary Highly diastereoselective BH₃/THF syn-reduction of the 3-hydroxy-1,3-diphenylpropan-1-one/BBr₃ complex3/BBr₃ (cf.Sarko) afforded themeso-diol4, whereas racemate5 was obtained by BH₃/THF reduction without complexation. Mesylation, exchange of mesylate by azide, and reduction with SnCl₂/thiophenol led to the diamines10 and11 which were also produced by reductive N-N cleavage of the 4,5-dihydropyrazole13.Dedicated to Prof. Dr.G. Wurm, Berlin, on the occasion of his 60^th birthday     

Methods for the synthesis of derivatives of 3-aminothietane (Review)

Methods for the production of derivatives of 3-aminothietane and 3-aminothietan-2-one are reviewed. Dedicated to Prof. Ivars Kalvinsh on the occasion of his 60^th birthday. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 655–682, May, 2007.     

A convenient synthesis of long-chain 4-substituted benzyloxycarbonyl alkanethiols for the formation of self assembled monolayers on metal substrates

New 4-substituted benzyl esters of 16-mercaptohexadecanoic acid were prepared by developing a practicable synthetic procedure and using readily available staring materials. The compounds synthesized have been characterized by NMR, MS, IR spectra and elemental analysis. The mercapto derivatives are precursors for the formation of self-assembled monolayers on metal substrates. Dedicated to Professor Dr. Manfred Hesse on the occasion of his 70 ^th birthday     

Studies on cyclic dipeptides,I: Aryl modifications ofcyclo-[Phe-His]

Summary Seven new cyclic dipeptides have been synthesized and tested for their applicability as tools to elucidate the mechanism of formation of mandelonitrile with (SS)-cyclo-[Phe-His] type catalysts. Conformational analyses based on¹H NMR spectra are presented for all prepared cyclic dipeptides.Dedicated to Prof. Dr. Dres. h.c.Herbert Oelschläger on the occasion of his 75^th birthday     

In memoriam Professor Zhen-Rong Lu (8 January 1946–5 January 2007)

Professor Zhen-Rong Lu, passed away on 5^th January 2007. Zhen-Rong Lu was born in Changshu in Jiangsu Province on 8^th January 1946. He received his B.Sc. in 1968 and M.Sc. in 1981 from Nanjing University. He worked for Suzhou Research Institute of Chemical Engineering (1968–1979); Department of Chemistry, Suzhou University (1981–1988); Department of Chemistry, The University of Melbourne, Australia (1988); Department of Chemistry, Monash University, Australia (1989); Testing and Analysis Center, Suzhou University, China (1990–2007). Main fields of interest have been: kinetics; relationship between thermal behavior and structure of complexes; crystal and molecular structure using thermal analysis and X-ray diffraction. He was awarded the third award of STA in 1995. Number of publications was 84 and the number of citations was 115. He was the writer of different chapters, i.e. Handbook of Thermal Analysis, Chapter 3–6, Published by John Wiley & Sons, Chichester 1998; Thermal Analysis Kinetics (in Chinese), Chapter 1, Science Press, Beijing 2001. Professional activities were: Member of the Chemical Thermodynamics and Thermal Analysis Committee (CTTA), Chinese Chemical Society (CCS) (1998–2007), Editorial Board of the Journal of Thermal Analyis and Calorimetry (2003–2007), Chairman of the Thermal Analysis Committee of Jiangsu Province (1991–2007), Chairman 3^rd Chinese Symposium on Thermoanalysis Kinetics and Thermokinetics Shihezi, China (2003). Professor Lu was a good and a cordial man always. He was extremely generous, always willing to see the positive side of life. He was a famous teacher and an outstanding researcher on a local and an international level as well. Besides his academic endeavors, he enjoyed his life spending quality time with his family and friends. We have suffered a great loss. We will miss him a lot as we have lost a true friend. May he rest in peace.     

1,3-Diphenylpropane-1,3-diamines,VIII. Reactions of lithiated oximes and oxime ethers with C=N-electrophiles

Summary The reaction of lithiated acetophenone oximes and their O-methyl ethers with benzylideneamines affords (1,3-diphenyl-3-hydroxyimino-1-propyl)-amines or their O-methyl derivatives, respectively, which are precursors of 1,3-diphenylpropane-1,3-diamines.Dedicated with warm regards to Prof. Dr. Dr. h.c. mult.H. Oelschläger, Jena (Germany) on the occasion of his 75^th birthday