1,2,3-Thiadiazole mit ungesättigten Seitenketten - Monomerbausteine für Photoresist-Materialien / 1,2,3-Thiadiazoles with Unsaturated Side Chains - Monomeric Building Blocks for Photoresists

1995 ◽  
Vol 50 (7) ◽  
pp. 1121-1126 ◽  
Author(s):  
Norbert Hanold ◽  
Helga Kalbitz ◽  
Mousa Al-Smadi ◽  
Herbert Meier
Keyword(s):  
Carboxylic Acids ◽  
Building Blocks ◽  
Thermal Polymerization ◽  
Ring Closure ◽  
Side Chains ◽  
Phosphonium Salts ◽  
High Tendency ◽  
Wittig Reactions

The phosphonium salts 4 are versatile reagents for the synthesis of 1,2,3-thiadiazoles 6 with unsaturated side chains. The preparation starts with the α-chloroketones 1 which are transformed in a stepwise process to the phosphonium salts 2 and 3. The reaction with SOCl2 leads to a regioselective ring closure 3 → 4 . Subsequent Wittig reactions yield the monomers 6, which exhibit with the exception of 6ac a high tendency for a thermal polymerization. Cleavage of the ester groups in 6ca and 6 cd generates the carboxylic acids 7ca and 7 cd which possess a higher stability.

Cyclizations of Alkoxyallenes: Mechanisms, Intermediates, ­Products – A Personal Account on Solved and Unsolved Problems with Unique Allene Building Blocks

Synthesis ◽  
2017 ◽  
Vol 49 (15) ◽  
pp. 3291-3302 ◽  
Author(s):  
Hans-Ulrich Reissig ◽  
Reinhold Zimmer
Keyword(s):  
Natural Products ◽  
Carboxylic Acids ◽  
Carbonyl Compounds ◽  
Building Blocks ◽  
Ring Closure ◽  
Pyridine Derivatives ◽  
Personal Account ◽  
Three Component Reaction ◽  
Hydroxylamine Derivatives ◽  
Oxazine Derivatives

The additions of lithiated alkoxyallenes to electrophiles, such as carbonyl compounds, thioketones, imines, and nitrones, provide the expected primary addition products. These alkoxyallene intermediates undergo ring-closure reactions under quite different conditions. Whereas allenyl hydroxylamine derivatives spontaneously cyclize to 1,2-oxazine derivatives, the related allenyl amines, thiols, and alcohols require, with distinct exceptions, promotion by acids, base, silver(I), or gold(I). The different mechanisms of these processes are discussed in this account. The serendipitous discovery of a novel three-component reaction of lithiated alkoxyallenes, nitriles, and carboxylic acids followed by a cyclization to pyridine derivatives is also reported and the mechanism involved is illustrated. This account also compiles exemplary examples of natural products and other compounds prepared by subsequent reactions of alkoxyallene-based cyclization products, but the fascinating ring-closing event of the allenyl intermediates is the main focus of this report.1 Introduction2 Cyclizations of Allenyl Hydroxylamines to 1,2-Oxazine Derivatives3 Cyclizations of Allenyl Amines to Dihydropyrrole Derivatives4 Cyclizations of Allenyl Imines to Pyrroles – Discovery of a New Three-Component Synthesis of Pyridines5 Cyclizations of Allenyl Thiols to Vinylthiiranes and Dihydrothiophene Derivatives6 Cyclizations of Allenyl Alcohols to Dihydrofuran Derivatives7 Conclusions

Hydrophobic Encapsulated Phosphonium Salts-Synthesis of Weakly Coordinating Cations and their Application in Wittig Reactions

2015 ◽  
Vol 21 (25) ◽  
pp. 9119-9125 ◽  
Author(s):  
Ralf Moritz ◽  
Manfred Wagner ◽  
Dieter Schollmeyer ◽  
Martin Baumgarten ◽  
Klaus Müllen
Keyword(s):  
Phosphonium Salts ◽  
Weakly Coordinating ◽  
Wittig Reactions

SYNTHESIS OF ISOTOPICALLY LABELLED OLEFINS VIA THE WITTIG REACTION

1965 ◽  
Vol 43 (5) ◽  
pp. 1614-1624 ◽  
Author(s):  
J. G. Atkinson ◽  
M. H. Fisher ◽  
D. Horley ◽  
A. T. Morse ◽  
R. S. Stuart ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Dimethyl Sulfoxide ◽  
Wittig Reaction ◽  
Low Molecular Weight ◽  
Phosphonium Salts ◽  
Reaction Conditions ◽  
Selective Labelling ◽  
Wittig Reactions

A new application of the Wittig reaction to the preparation of olefins of low molecular weight which allows selective labelling in the vinyl or allyl positions with isotopes of hydrogen and carbon has been developed. Using the modification of the Wittig reaction introduced by E. J. Corey, in which a solution of the methylsulfinyl carbanion in dimethyl sulfoxide serves as the base, a series of olefins from C2 to C8 were synthesized. The synthesis was applied to the preparation of the following labelled compounds: 5-methylene-14C-bicyclo[2.2.1]hept-2-ene; propene-1-14C; 1-butene-1-14C; propene-1-d1; 2-methylpropene-1,1-d2; 2-methyl-d3-propene-3,3,3-d3; 2-methyl-2-butene-4,4,4-d3; 2-methyl-d3-2-butene-1,1,1-d3; methylene-d2-cyclohexane. For the synthesis of carbon-labelled olefins the reaction has few limitations since the intermediates and products are isotopically stable under the reaction conditions. Deuterium-labelled olefins can be obtained from deuterated formaldehyde or β-deuterated phosphonium salts, but α-deuteroketones and aldehydes and α-deuterophosphonium salts lose the isotope to the solvent.In all the Wittig reactions, benzene was formed as a by-product in 10–15% yield. The mechanism of benzene formation is probably analogous to that proposed by Seyferth involving the decomposition of a pentacovalent phosphorous intermediate.

scholarly journals NaIO4/Br- as a mild system for the oxidation of 1-methyl-anthra-9,10-quinones

2015 ◽  
Author(s):  
Marcin Cybulski ◽  
Adam Formela ◽  
Katarzyna Sidoryk ◽  
Olga Michalak ◽  
Anna Rosa ◽  
...  
Keyword(s):  
High Pressure ◽  
Carboxylic Acids ◽  
Scale Up ◽  
Lithium Bromide ◽  
Cost Effective ◽  
Building Blocks ◽  
Multidrug Resistant ◽  
Resistant Cell ◽  
Direct Oxidation ◽  
Reaction Conditions

One of the anthraquinone classes comprises compounds with a carbonyl group. These natural or synthetic anthraquinones find their application as building blocks in the synthesis of the compounds with a biological activity. Recently, 4-substituted anthra-9,10-quinone-1-carboxylic acids (2) have been used as key intermediates in the synthesis of patented compounds (3) with anticancer activity against multidrug resistant cell lines. Although 2,7-dihydro-3H-dibenz[de,h]cinnolin-3,7-diones (3) were successfully synthetized in a small laboratory scale, several problems were observed during the preparation of their acid intermediates (2) in a multi-gram scale. The known methods for the preparation of 2 are based on the oxidation of the methyl group in anthra-9,10-quinones (1). The most common are: the oxidation with the diluted nitric acid under high pressure in a sealed tube at the temperature of 195-220 oC, the oxidation in nitrobenzene by passing chlorine gas through the reaction mixture at the temperature of 160-170 oC or in a presence of the fuming sulphuric acid. The mentioned methods require aggressive reagents and specific reaction conditions including high pressure and temperature. Thus, there was a need to find a new efficient, cost-effective and reproducible synthetic method of preparation of 2. While searching literature it was found that the direct oxidation of alkylarenes mediated by the sodium periodate/lithium bromide combination produces benzyl acetates throughout benzyl bromides in the acetic acid, or benzylic acids in the diluted inorganic acid. Based on these results we examined a variety of reaction conditions with or without the bromine source and the oxidizing anion. As a result, a novel procedure for the preparation of highly pure 4-substituted anthra-9,10-quinone-1-carboxylic acids (HPLC > 99.5%) using oxidizing anion/ brominating reagent system was developed. It enabled 2 isolation by the simple filtration of the reaction mixture and was applied in the scale-up of 2,7-dihydro-3H-dibenz[de,h]cinnolin-3,7-dione derivatives.

scholarly journals Palladium(II)-Catalyzed C(sp3)–H Activation of N,O-Ketals towards a Method for the β-Functionalization of Ketones

Synlett ◽  
2019 ◽  
Vol 30 (04) ◽  
pp. 454-458 ◽  
Author(s):  
Danny Ho ◽  
Jonas Calleja ◽  
Matthew Gaunt
Keyword(s):  
Carboxylic Acids ◽  
Functional Groups ◽  
Building Blocks ◽  
Activation Pathway ◽  
Bond Forming ◽  
Aliphatic Ketones ◽  
Palladium Catalyzed

A method for the formal β-functionalization of aliphatic ketones via a palladium-catalyzed sp3 C–H activation pathway is reported. An N,O-ketal directs an aliphatic C–H carbonylation to form γ-lactams which upon hydrolysis generate γ-keto carboxylic acids. This C–C bond-forming reaction is tolerant of a range of functional groups, enabling the synthesis of a range of synthetically important building blocks. Furthermore, the concepts underlying this transformation have also enabled the development of a related C–H alkenylation process to highly functionalised heterocycles.

scholarly journals Modular triazine-based carborane-containing carboxylic acids – synthesis and characterisation of potential boron neutron capture therapy agents made of readily accessible building blocks

2019 ◽  
Vol 48 (29) ◽  
pp. 10834-10844 ◽  
Author(s):  
Martin Kellert ◽  
Dennis J. Worm ◽  
Paul Hoppenz ◽  
Menyhárt B. Sárosi ◽  
Peter Lönnecke ◽  
...  
Keyword(s):  
Carboxylic Acid ◽  
Carboxylic Acids ◽  
Boron Neutron Capture Therapy ◽  
Neutron Capture ◽  
Building Blocks ◽  
Neutron Capture Therapy ◽  
Boron Neutron Capture

Boron-rich carboxylic acid derivatives were synthesised as coupling partners for tumour-selective biomolecules with applications as selective BNCT agents.

scholarly journals Recent advances in phosphoranyl radical-mediated deoxygenative functionalisation

2020 ◽  
Vol 7 (16) ◽  
pp. 2319-2324 ◽  
Author(s):  
Xiao-Qiang Hu ◽  
Ye-Xing Hou ◽  
Zi-Kui Liu ◽  
Yang Gao
Keyword(s):  
Carboxylic Acids ◽  
Building Blocks ◽  
Recent Advances ◽  
Phosphoranyl Radical

Alcohols and carboxylic acids have been established as versatile building blocks in the assembly of various carbon frameworks.

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