5724-81-2Relevant articles and documents
An Unexpected “Step-Conjugated” Biphosphole via Unique P–P Bond Formation
Wang, Zisu,Asok, Nayanthara,Gaffen, Joshua,Gottlieb, Yael,Bi, Wenhua,Gendy, Chris,Dobrovetsky, Roman,Baumgartner, Thomas
, p. 2628 - 2643 (2018)
The synthesis of a π-conjugated organophosphorus species with bridging P–P unit is reported. Because of the pyramidal geometry of the phosphorus centers, the molecular scaffold provides intriguing electronic communication throughout the three-dimensional structure via π-σ-π conjugation in stepwise fashion. The dimeric species was serendipitously found to be accessible via a reaction of the corresponding P-amino-phosphole precursor through mediation with the hard Lewis acid BF3. We provide detailed mechanistic studies toward a suitable reaction mechanism that was also verified via computational means. Moreover, we elaborate the utility of the biphosphole via phosphorus functionalization that lends further proof for the step conjugation provided by the unique phosphorus-based molecular architecture. Fundamental chemistry lays the foundation for future innovation with considerable impact on next-generation technologies. Main-group chemistry in particular provides a unique angle with regard to structure and bonding, which makes it an intriguing state-of-the-art avenue for the development of readily accessible advanced materials with significantly value-added functionality, that is, optical and electronic properties. The need for innovative molecular architectures is particularly evident in the rapidly accelerating development of conjugated organic building blocks because their high utility for a variety of sustainable energy applications is now well established. Herein, we report a unique type of phosphorus-based “step-conjugated” building block via an unexpected reaction that we have elucidated mechanistically in our studies. Reaction of a P-amino-dithienophosphole with the hard Lewis acid, BF3, leads to a dimeric species via a P–P bond-forming reaction, as supported through systematic mechanistic studies. Because of the inherent pyramidal geometry of the phosphorus centers, the dimer shows extended step-like conjugation through the scaffold via π-σ-π conjugation, which makes it an intriguing new building block for organic hybrid materials.
Isolation and stabilization of a pheromone in crystalline molecular capsules
Xiao, Wenchang,Hu, Chunhua,Ward, Michael D.
, p. 3197 - 3200 (2013)
The active monomer form of the male-produced pheromone of the Mediterranean fruit fly can be isolated selectively from its equilibrating trimer species by encapsulation within a calixarene pocket built into a hydrogen-bonded framework from guanidinium 4-sulfocalix[4]arene. Encapsulation of the Δ1- pyrroline guest significantly perturbs the assembly of the quasihexagonal two-dimensional guanidinium-sulfonate network of the guest-free framework, to the extent that guanidinium ions are excluded from some sites to accommodate the steric requirements of the guest. Nonetheless, single crystal X-ray diffraction reveals the preservation of a layered structrure in which the calixarene capsules stack in an antiparallel configuration. These observations illustrate that the binding of the pheromone monomer by the calixarene is sufficiently strong to overcome the loss of guanidinium-sulfonate hydrogen bonds, which is corroborated by the strong binding constants measured in solution. The solid-state encapsulation stabilizes the otherwise volatile unstable monomer form, suggesting an effective strategy for the storage, application, and controlled release of an important agricultural adjuvant.
Photoextrusion of molecular nitrogen from annulated 5-alkylidene-4,5-dihydro-1H-tetrazoles: Annulated iminoaziridines and the first triplet diazatrimethylenemethane
Quast, Helmut,Fuss, Andreas,Nuedling, Wolfgang
, p. 317 - 327 (1998)
Deprotonation of the annulated tetrazolium salts 4, 6, 8, 10, and 12 with sodium or potassium hydride yields the alkyh'denedihydrotetrazoles 5, 7, 9, 11, and 13, respectively. While 5a and b are unstable, even in solution at low temperatures, 7, 9, 11, and 13 form yellow oils that are distilled under high vacuum. - Irradiation of solutions of 7, 9, and 11 in [D8]toluene at -60°C yields, besides molecular nitrogen, annulated iminoaziridines that have an exocyclic CN double bond, i.e. 14, 16, and 18, respectively. In addition, an equal amount of the isomer 19 with the endocyclic CN double bond is formed from 11. On thermolysis, 14, 16, and 18 undergo [2 + 1] cycloreversion into methyl isocyanide and the cyclic imines 15, 17, and 20, respectively. By contrast, 19 rearranges thermally to yield 18. While the doubly bridged alkylidenedihydrotetrazole 13a affords only unidentified decomposition products on photolysis, its methyl homologue 13b is converted into the hexahydronaphthyridine 22 which is also formed on thermolysis. - Irradiation of 13b in a 2-methyltetrahydrofuran or butyronitrile matrix at 77 K yields a triplet diradical showing a four-line EPR spectrum centred at 3362 G and a half-field transition (at 1669 G) with a hyperfine structure. The zero-field splitting parameters |D/hc| = 0.031 cm-1 and |E/hc| = 0.0014 cm-1 are obtained by simulation of the EPR spectrum. The signal-carrier is assigned the diazatrimethylenemethane structure 23 on the basis of the close similarity between its EPR spectrum and those of trimethylenemethane (28) and tris(N-methylimino)methane (29). - Structural features are discussed that are responsible for the observed differences between the photochemical pathways.
OXIDATIVE SPALTUNG VON 2-(PYRROLIDINOMETHYL)PYRIDIN-1-OXID MIT ANSCHLIESSENDER REKOMBINATION UND DIE KRISTALLSTRUKTUR VON (E)-2-(1-PYRROLIN-3-YLIDENMETHYL)PYRIDIN-1-OXID
Moehrle, H.,Troester, G.,Linden, M.,Mootz, D.,Wunderlich, H.
, p. 2881 - 2885 (1981)
Mercury EDTA dehydrogenation of 2-(pyrrolidinomethyl)-pyridine-1-oxide (1) yields the pyrrolidone 5, which may be accounted for by a neighbouring effect of the amine oxide group.For an additional basic product the structure of (E)-2-(1-pyrroline-3-ylidenemethyl)-pyridine-1-oxide (11) has been proved by X-ray crystallography and synthesis.This indicates a cleavage of the doubly dehydrogenated product followed by recombination.
CHARACTERIZATION OF MAIZE POLYAMINE OXIDASE
Federico, Rodolfo,Cona, Alessandra,Angelini, Riccardo,Schinina, M. Eugenia,Giartosio, Anna
, p. 2411 - 2414 (1990)
Some structural and biochemical characteristics of polyamine oxidase (PAO) purified from maize shoots have been examined.The enzyme has only alanine as N-terminal amino acid and its N-terminal sequence shows a significant degree of homology with tryptophan 2-monooxygenase from Pseudomonas syringae pv. savastanoi.The pH optimum for the stability of the native enzyme is 5, similar to that of the barley leaf enzyme.Calorimetric analysis shows a single two-state transition at pH 6 with Tm 49.8 deg.At pH 5 the thermal stability is increased by more than 14 deg.Amine oxidation products, Δ1-pyrroline and diazabicyclononane, are competitive inhibitors of PAO activity (apparent Ki = 400 and 100 μM respectively).Moreover these compounds improve the thermal stability of the enzyme.N1-Acetylspermine, which is a good substrate for mammalian PAO, acts as a non-competitive inhibitor for the plant enzyme.
Structural equilibrium and ring-chain tautomerism of aqueous solutions of 4-aminobutyraldehyde
Struve, Casper,Christophersen, Carsten
, p. 1907 - 1914 (2003)
NMR spectroscopy of aqueous solutions of 4-aminobutyraldehyde in the range 0 pH 13 established the occurrence of protonated and hydrated amino aldehydes in equilibrium with pyrrolines, and pyrrolinium salts.
Mexican fruit fly attractants: Effects of 1-pyrroline and other amines on attractiveness of a mixture of ammonia, methylamine, and putrescine
Robacker,Demilo,Voaden
, p. 1263 - 1280 (1997)
Several amines were tested alone and in combination with AMPu, an attractant mixture containing ammonium bicarbonate or ammonium carbonate, methylamine hydrochloride, and putrescine, for attractiveness to Mexican fruit flies (Anastrepha ludens Loew). In laboratory bioassay, 1-pyrroline, 3-pyrroline, 2-(methylamino)ethanol, spermidine, spermine, and indole-3-acetic acid were significantly more attractive than solvent controls. In orchard tests, traps bailed with combinations of AMPu with dimethylamine hydrochloride, ethylamine, 2,5-dimethylpyrazine, or pyrrolidine captured fewer flies than traps baited with AMPu alone. Traps containing AMPu plus additional ammonium bicarbonate were much less attractive than AMPu alone. Combinations of AMPu with 1-pyrroline were about 50% more attractive than AMPu alone to both males and females. Combinations of AMPu with 3-pyrroline were not significantly more attractive than AMPu alone.
A rapid synthesis of racemic brevioxime
Parsons,Karadogan,Macritchie
, p. 257 - 259 (2001)
Racemic brevioxime has been synthesised starting from N-propionyl-2-pyrroline by intramolecular cyclisation of a β-ketoamide using nitrosyl chloride.
Diversification of Unprotected Alicyclic Amines by C?H Bond Functionalization: Decarboxylative Alkylation of Transient Imines
Paul, Anirudra,Kim, Jae Hyun,Daniel, Scott D.,Seidel, Daniel
supporting information, p. 1625 - 1628 (2020/11/30)
Despite extensive efforts by many practitioners in the field, methods for the direct α-C?H bond functionalization of unprotected alicyclic amines remain rare. A new advance in this area utilizes N-lithiated alicyclic amines. These readily accessible intermediates are converted to transient imines through the action of a simple ketone oxidant, followed by alkylation with a β-ketoacid under mild conditions to provide valuable β-amino ketones with unprecedented ease. Regioselective α′-alkylation is achieved for substrates with existing α-substituents. The method is further applicable to the convenient one-pot synthesis of polycyclic dihydroquinolones through the incorporation of a SNAr step.
α-C-H Bond Functionalization of Unprotected Alicyclic Amines: Lewis-Acid-Promoted Addition of Enolates to Transient Imines
Kim, Jae Hyun,Paul, Anirudra,Ghiviriga, Ion,Seidel, Daniel
supporting information, p. 797 - 801 (2021/02/06)
Enolizable cyclic imines, obtained in situ from their corresponding lithium amides by oxidation with simple ketone oxidants, are readily alkylated with a range of enolates to provide mono- and polycyclic β-aminoketones in a single operation, including the natural product (±)-myrtine. Nitrile anions also serve as competent nucleophiles in these transformations, which are promoted by BF3 etherate. β-Aminoesters derived from ester enolates can be converted to the corresponding β-lactams.
