7299-55-0Relevant articles and documents
Oxidative methoxycarbonylation of propyne and allene with carbon monoxide and methanol in the presence of copper-palladium catalyst
Mal'kina,Kudyakova,Nosyreva,Afonin,Trofimov
, p. 1088 - 1092 (2002)
A direct oxidative methoxycarbonylation of propyne with carbon monoxide in methanol medium in the presence of copper-palladium catalytic system results in methyl 2-butynoate in 18-31% yield. Depending on reaction conditions allene provides either a mixture of methyl 2-(chloromethyl)acrylate and methyl 2-(methoxymethyl)acrylate (～3-4:1) in overall yield 16-23%, or methyl 2-(methoxymethyl)acrylate in 19% yield.
Covalent Adaptable Networks with Tunable Exchange Rates Based on Reversible Thiol–yne Cross-Linking
Du Prez, Filip E.,Guerre, Marc,Maes, Diederick,Unal, Kamil,Van Herck, Niels,Winne, Johan M.
supporting information, p. 3609 - 3617 (2020/02/04)
The design of covalent adaptable networks (CANs) relies on the ability to trigger the rearrangement of bonds within a polymer network. Simple activated alkynes are now used as versatile reversible cross-linkers for thiols. The click-like thiol–yne cross-linking reaction readily enables network synthesis from polythiols through a double Michael addition with a reversible and tunable second addition step. The resulting thioacetal cross-linking moieties are robust but dynamic linkages. A series of different activated alkynes have been synthesized and systematically probed for their ability to produce dynamic thioacetal linkages, both in kinetic studies of small molecule models, as well as in stress relaxation and creep measurements on thiol–yne-based CANs. The results are further rationalized by DFT calculations, showing that the bond exchange rates can be significantly influenced by the choice of the activated alkyne cross-linker.
Spectroscopy and Photochemistry of Triplet 1,3-Dimethylpropynylidene (MeC3Me)
Knezz, Stephanie N.,Waltz, Terese A.,Haenni, Benjamin C.,Burrmann, Nicola J.,McMahon, Robert J.
, p. 12596 - 12604 (2016/10/07)
Photolysis (λ > 472 nm) of 2-diazo-3-pentyne (11) affords triplet 1,3-dimethylpropynylidene (MeC3Me, 33), which was characterized spectroscopically in cryogenic matrices. The infrared, electronic absorption, and electron paramagnetic resonance spectra of MeC3Me (33) are compared with those of the parent system (HC3H) to ascertain the effect of alkyl substituents on delocalized carbon chains of this type. Quantum chemical calculations (CCSD(T)/ANO1) predict an unsymmetrical equilibrium structure for triplet MeC3Me (33), but they also reveal a very shallow potential energy surface. The experimental IR spectrum of triplet MeC3Me (33) is best interpreted in terms of a quasilinear, axially symmetric structure. EPR spectra yield zero-field splitting parameters that are typical for triplet carbenes with axial symmetry (|D/hc| = 0.63 cm-1, |E/hc| = β 0 cm-1), while theoretical analysis suggests that the methyl substituents confer significant spin polarization to the carbon chain. Upon irradiation into the near-UV electronic absorption (λmax 350 nm), MeC3Me (33) undergoes 1,2-hydrogen migration to yield pent-1-en-3-yne (4), a photochemical reaction that is typical of carbenes bearing a methyl substituent. This facile process apparently precludes photoisomerization to other interesting C5H6 isomers, in contrast to the rich photochemistry of the parent C3H2 system.
Total synthesis of hematoporphyrin and protoporphyrin; A conceptually new approach
Martin, Pierre,Mueller, Markus,Flubacher, Dietmar,Boudier, Andreas,Spielvogel, Dirk
, p. 204 - 206 (2013/07/05)
The total synthesis of protoporphyrin IX and its disodium salt using a new alternative method to the classical MacDonald condensation is reported. The key step is the reaction of the new unsymmetrical diiodo dipyrrylmethane 1 with the known dipyrrylmethane 2. Coupling of the two fragments leads directly to porphyrin 3 without the need of an oxidizing agent. The new methodology is well suited for the synthesis of protoporphyrin IX derivatives on a multi-100 g scale in good quality without the need for chromatography. Furthermore, these preparations are completely free of any contaminant of animal origin, which represents a real improvement in the manufacturing of protoporphyrin IX derivatives. Schweizerische Chemische Gesellschaft.
