Unsaturated azacyclopropane compounds that are three-membered heterocycles of a nitrogen and two carbon atoms.

Analysis of the membrane-interacting domains of myelin basic protein by hydrophobic photolabeling. (1/145)

Myelin basic protein is a water soluble membrane protein which interacts with acidic lipids through some type of hydrophobic interaction in addition to electrostatic interactions. Here we show that it can be labeled from within the lipid bilayer when bound to acidic lipids with the hydrophobic photolabel 3-(trifluoromethyl)-3-(m-[125I]iodophenyl)diazirine (TID) and by two lipid photolabels. The latter included one with the reactive group near the apolar/polar interface and one with the reactive group linked to an acyl chain to position it deeper in the bilayer. The regions of the protein which interact hydrophobically with lipid to the greatest extent were determined by cleaving the TID-labeled myelin basic protein (MBP) with cathepsin D into peptides 1-43, 44-89, and 90-170. All three peptides from lipid-bound protein were labeled much more than peptides from the protein labeled in solution. However, the peptide labeling pattern was similar for both environments. The two peptides in the N-terminal half were labeled similarly and about twice as much as the C-terminal peptide indicating that the N-terminal half interacts hydrophobically with lipid more than the C-terminal half. MBP can be modified post-translationally in vivo, including by deamidation, which may alter its interactions with lipid. However, deamidation had no effect on the TID labeling of MBP or on the labeling pattern of the cathepsin D peptides. The site of deamidation has been reported to be in the C-terminal half, and its lack of effect on hydrophobic interactions of MBP with lipid are consistent with the conclusion that the N-terminal half interacts hydrophobically more than the C-terminal half. Since other studies of the interaction of isolated N-terminal and C-terminal peptides with lipid also indicate that the N-terminal half interacts hydrophobically with lipid more than the C-terminal half, these results from photolabeling of the intact protein suggest that the N-terminal half of the intact protein interacts with lipid in a similar way as the isolated peptide. The similar behavior of the intact protein to that of its isolated peptides suggests that when the purified protein binds to acidic lipids, it is in a conformation which allows both halves of the protein to interact independently with the lipid bilayer. That is, it does not form a hydrophobic domain made up from different parts of the protein.  (+info)

NADH-quinone oxidoreductase: PSST subunit couples electron transfer from iron-sulfur cluster N2 to quinone. (2/145)

The proton-translocating NADH-quinone oxidoreductase (EC 1.6.99.3) is the largest and least understood enzyme complex of the respiratory chain. The mammalian mitochondrial enzyme (also called complex I) contains more than 40 subunits, whereas its structurally simpler bacterial counterpart (NDH-1) in Paracoccus denitrificans and Thermus thermophilus HB-8 consists of 14 subunits. A major unsolved question is the location and mechanism of the terminal electron transfer step from iron-sulfur cluster N2 to quinone. Potent inhibitors acting at this key region are candidate photoaffinity probes to dissect NADH-quinone oxidoreductases. Complex I and NDH-1 are very sensitive to inhibition by a variety of structurally diverse toxicants, including rotenone, piericidin A, bullatacin, and pyridaben. We designed (trifluoromethyl)diazirinyl[3H]pyridaben ([3H]TDP) as our photoaffinity ligand because it combines outstanding inhibitor potency, a suitable photoreactive group, and tritium at high specific activity. Photoaffinity labeling of mitochondrial electron transport particles was specific and saturable. Isolation, protein sequencing, and immunoprecipitation identified the high-affinity specifically labeled 23-kDa subunit as PSST of complex I. Immunoprecipitation of labeled membranes of P. denitrificans and T. thermophilus established photoaffinity labeling of the equivalent bacterial NQO6. Competitive binding and enzyme inhibition studies showed that photoaffinity labeling of the specific high-affinity binding site of PSST is exceptionally sensitive to each of the high-potency inhibitors mentioned above. These findings establish that the homologous PSST of mitochondria and NQO6 of bacteria have a conserved inhibitor-binding site and that this subunit plays a key role in electron transfer by functionally coupling iron-sulfur cluster N2 to quinone.  (+info)

Inhibition of DNA replicon initiation by 4-nitroquinoline 1-oxide, adriamycin, and ethyleneimine. (3/145)

The effects of three widely differing chemical carcinogens, 4-nitroquinoline 1-oxide, Adriamycin, and ethyleneimine, on DNA replication were studied by pulse labeling of DNA with [3H]thymidine and sedimentation analysis with alkaline sucrose gradients. At doses that reduced the rate of DNA synthesis to 30 to 60% of control values, only ethyleneimine produced damage that resulted in lower molecular weights of parental DNA. All three chemicals inhibited replicon initiation, but to differing extents. Inhibition of replicon initiation was the first clearly identified effect of 4-nitroquinoline 1-oxide and was the main cause of inhibition of DNA synthesis. Ethyleneimine caused severe inhibition of replicon initiation, but blocks to chain elongation also contributed significantly to the inhibition of overall DNA synthesis. Adriamycin affected replicon initiation to a small but significant extent; the primary cause of inhibition of DNA synthesis by this drug was a slowing of the rate of chain elongation. These results indicate that inhibition of replicon initiation is an important mechanism for the action of DNA-damaging agents in mammalian cells and strengthen the concept that control of DNA replication depends on the structural integrity of a chromosomal subunit that consists of several replicons.  (+info)

The membrane binding domains of prostaglandin endoperoxide H synthases 1 and 2. Peptide mapping and mutational analysis. (4/145)

Prostaglandin endoperoxide H synthases 1 and 2 (PGHS-1 and -2) are the major targets of nonsteroidal anti-inflammatory drugs. Both isozymes are integral membrane proteins but lack transmembrane domains. X-ray crystallographic studies have led to the hypothesis that PGHS-1 and -2 associate with only one face of the membrane bilayer through a novel, monotopic membrane binding domain (MBD) that is comprised of four short, consecutive, amphipathic alpha-helices (helices A-D) that include residues 74-122 in ovine PGHS-1 (oPGHS-1) and residues 59-108 in human PGHS-2 (hPGHS-2). Previous biochemical studies from our laboratory showed that the MBD of oPGHS-1 lies somewhere between amino acids 25 and 166. In studies reported here, membrane-associated forms of oPGHS-1 and hPGHS-2 were labeled using the hydrophobic, photoactivable reagent 3-trifluoro-3-(m-[(125)I]iodophenyl)diazirine, isolated, and cleaved with AspN and/or GluC, and the photolabeled peptides were sequenced. The results establish that the MBDs of oPGHS-1 and hPGHS-2 reside within residues 74-140 and 59-111, respectively, and thus provide direct provide biochemical support for the hypothesis that PGHS-1 and -2 do associate with membranes through a monotopic MBD. We also prepared HelA, HelB, and HelC mutants of oPGHS-1, in which, for each helix, three or four hydrophobic residues expected to protrude into the membrane were replaced with small, neutral residues. When expressed in COS-1 cells, HelA and HelC mutants exhibited little or no catalytic activity and were present, at least in part, as misfolded aggregates. The HelB mutant retained about 20% of the cyclooxygenase activity of native oPGHS-1 and partitioned in subcellular fractions like native oPGHS-1; however, the HelB mutant exhibited an extra site of N-glycosylation at Asn(104). When this glycosylation site was eliminated (HelB/N104Q mutation), the mutant lacked cyclooxygenase activity. Thus, our mutational analyses indicate that the amphipathic character of each helix is important for the assembly and folding of oPGHS-1 to a cyclooxygenase active form.  (+info)

Examining the noncompetitive antagonist-binding site in the ion channel of the nicotinic acetylcholine receptor in the resting state. (5/145)

3-Trifluoromethyl-3-(m-[(125)I]iodophenyl)diazirine ([(125)I]TID) has been shown to be a potent noncompetitive antagonist (NCA) of the nicotinic acetylcholine receptor (AChR). Amino acids that contribute to the binding site for [(125)I]TID in the ion channel have been identified in both the resting and desensitized state of the AChR (White, B.H., and Cohen, J.B. (1992) J. Biol. Chem. 267, 15770-15783). To characterize further the structure of the NCA-binding site in the resting state channel, we have employed structural analogs of TID. The TID analogs were assessed by the following: 1) their ability to inhibit [(125)I]TID photoincorporation into the resting state channel; 2) the pattern, agonist sensitivity, and NCA inhibition of [(125)I]TID analog photoincorporation into AChR subunits. The addition of a primary alcohol group to TID has no demonstrable effect on the interaction of the compound with the resting state channel. However, conversion of the alcohol function to acetate, isobutyl acetate (TIDBIBA), or to trimethyl acetate leads to rightward shifts in the concentration-response curves for inhibition of [(125)I]TID photoincorporation into the AChR channel and a progressive reduction in the agonist sensitivity of [(125)I]TID analog photoincorporation into AChR subunits. Inhibition of [(125)I]TID analog photoincorporation by NCAs (e.g. tetracaine) as well as identification of the sites of [(125)I]TIDBIBA photoincorporation in the deltaM2 segment indicate a common binding locus for each TID analog. We conclude that relatively small additions to TID progressively reduce its ability to interact with the NCA site in the resting state channel. A model of the NCA site and resting state channel is presented.  (+info)

Assembly of archaeal signal recognition particle from recombinant components. (6/145)

Signal recognition particle (SRP) takes part in protein targeting and secretion in all organisms. Searches for components of archaeal SRP in primary databases and completed genomes indicated that archaea possess only homologs of SRP RNA, and proteins SRP19 and SRP54. A recombinant SRP was assembled from cloned, expressed and purified components of the hyperthermophilic archaeon Archaeoglobus fulgidus. Recombinant Af-SRP54 associated with the signal peptide of bovine pre-prolactin translated in vitro. As in mammalian SRP, Af-SRP54 binding to Af-SRP RNA required protein Af-SRP19, although notable amounts bound in absence of Af-SRP19. Archaeoglobus fulgidus SRP proteins also bound to full-length SRP RNA of the archaeon Methanococcus jannaschii, to eukaryotic human SRP RNA, and to truncated versions which corresponded to the large domain of SRP. Dependence on SRP19 was most pronounced with components from the same species. Reconstitutions with heterologous components revealed a significant potential of human SRP proteins to bind to archaeal SRP RNAs. Surprisingly, M.jannaschii SRP RNA bound to human SRP54M quantitatively in the absence of SRP19. This is the first report of reconstitution of an archaeal SRP from recombinantly expressed purified components. The results highlight structural and functional conservation of SRP assembly between archaea and eucarya.  (+info)

Molecular models of the structural arrangement of subunits and the mechanism of proton translocation in the membrane domain of F(1)F(0) ATP synthase. (7/145)

Subunit c of the proton-transporting ATP synthase of Escherichia coli forms an oligomeric complex in the membrane domain that functions in transmembrane proton conduction. The arrangement of subunit c monomers in this oligomeric complex was studied by scanning mutagenesis. On the basis of these studies and structural information on subunit c, different molecular models for the potential arrangement of monomers in the c-oligomer are discussed. Intersubunit contacts in the F(0) domain that have been analysed in the past by chemical modification and mutagenesis studies are summarised. Transient contacts of the c-oligomer with subunit a might play a crucial role in the mechanism of proton translocation. Schematic models presented by several authors that interpret proton transport in the F(0) domain by a relative rotation of the c-subunit oligomer against subunit a are reviewed against the background of the molecular models of the oligomer.  (+info)

A conformational intermediate between the resting and desensitized states of the nicotinic acetylcholine receptor. (8/145)

The structural changes induced in the nicotinic acetylcholine receptor by two noncompetitive channel blockers, proadifen and phencyclidine, have been studied by infrared difference spectroscopy and using the conformationally sensitive photoreactive noncompetitive antagonist 3-(trifluoromethyl)-3-m-([(125)I]iodophenyl)diazirine. Simultaneous binding of proadifen to both the ion channel pore and neurotransmitter sites leads to the loss of positive markers near 1663, 1655, 1547, 1430, and 1059 cm(-)(1) in carbamylcholine difference spectra, suggesting the stabilization of a desensitized conformation. In contrast, only the positive markers near 1663 and 1059 cm(-)(1) are maximally affected by the binding of either blocker to the ion channel pore suggesting that the conformationally sensitive residues vibrating at these two frequencies are stabilized in a desensitized-like conformation, whereas those vibrating near 1655 and 1430 cm(-)(1) remain in a resting-like state. The vibrations at 1547 cm(-)(1) are coupled to those at both 1663 and 1655 cm(-)(1) and thus exhibit an intermediate pattern of band intensity change. The formation of a structural intermediate between the resting and desensitized states in the presence of phencyclidine is further supported by the pattern of 3-(trifluoromethyl)-3-m-([(125)I]iodophenyl)diazirine photoincorporation. In the presence of phencyclidine, the subunit labeling pattern is distinct from that observed in either the resting or desensitized conformations; specifically, there is a concentration-dependent increase in the extent of photoincorporation into the delta-subunit. Our data show that domains of the nicotinic acetylcholine receptor interconvert between the resting and desensitized states independently of each other and suggest a revised model of channel blocker action that involves both low and high affinity agonist binding conformational intermediates.  (+info)

Azirines are a class of heterocyclic organic compounds that contain a three-membered ring consisting of two carbon atoms and one nitrogen atom. The structure of azirines can be represented by the chemical formula C2H2NR, where R is a hydrogen atom or a functional group.

Azirines are highly strained molecules due to the small size of the ring, which makes them reactive and useful in organic synthesis. They can undergo various reactions, such as cycloaddition, to form larger and more complex molecules. Azirines have been found to exhibit biological activity and are being investigated for their potential use in medicinal chemistry.

It is important to note that azirines are not a medical term per se, but rather a chemical term used to describe a specific class of organic compounds.

2H-Azirines can be considered strained imines and are isolable. 2H-Azirine is most often obtained by the thermolysis of vinyl ... An azirine is an intermediate in the Neber rearrangement. Dysidazirine, one of only a few naturally-occurring azirines Teresa M ... There are two isomers of azirine: 1H-Azirines with a carbon-carbon double bond are not stable and rearrange to the tautomeric ... Azirine can be generated during photolysis of isoxazole. Due to the weak N-O bond, the isoxazole ring tends to collapse under ...
However, azirine intermediates have been isolated. The mechanism is postulated to proceed via a nitrene intermediate. ... Gilchrist, T. L. (2001). "Activated 2H-Azirines as Dienophiles and Electrophiles" (PDF). Aldrichimica Acta. 34 (2): 51. ...
... isobornyl 2H-azirine-3-carboxylates". J. Chem. Soc., Perkin Trans. 1 (16): 1911-1919. doi:10.1039/B202321K. ISSN 1472-7781. The ... vinyl azides 19 decompose into 2H-azirines 20. Alkyl azides with low nitrogen-content ((nC + nO) / nN ≥ 3) are relatively ...
"Electronically Mediated Selectivity in Ring Opening of 1-Azirines. The 3-X Mode: Convenient Route to 3-Oxazolines". The Journal ...
Chemically, it is a 2H-azirine derivative. Dysidazirine synthesis was reported for the first time in 1995. Dysidazirine kills ... Davis, Franklin A.; Reddy, G. Venkat; Liu, Hu (1995). "Asymmetric Synthesis of 2H-Azirines: First Enantioselective Synthesis of ...
"3-Methyl-2H-azirine-2-carboxylic acid". pubchem.ncbi.nlm.nih.gov. Communications, EBCONT. "Azirinomycin". roempp.thieme.de. ... Azirinomycin is an antibiotic azirine derivative with the molecular formula C4H5NO2 which is produced by the bacterium ...
Alkynes, carbonyl compounds, imines and azirines can also act as dipolarophile. Nitrile ylides react with weak acids like ... by the photochemical ring opening of azirines and by dehydrochlorination of imidoyl chlorides. The latter is the most reliable ...
2, p. 349 Padwa, A.; Blacklock, T.; Tremper, A. "3-Phenyl-2H-Azirine-2-carboxaldehyde". Organic Syntheses.; Collective Volume, ...
The racemic 2H-azirines was first applied and one enantiomer of the 2H-azirine would react with chiral Cu-enolated complex to ... Copper-catalyzed asymmetric Mannich reaction of 2H-azirines with β-keto amides (2018) In 2018, Lin, Feng, and coworkers ... Copper(I)-catalyzed asymmetric decarboxylative Mannich reaction of 2H-azirines (2019) In 2019, Yin and coworkers used 2H- ... Zn-ProPhenol catalyzed asymmetric Mannich reaction of 2H-azirines with alkynyl cycloalkyl ketones (2020) In 2020, Trost and ...
Due to the weak N-O bond, the isoxazole ring tends to collapse under UV irradiation, rearranging to oxazole through azirine ... Meanwhile, the azirine intermediate can react with nucleophiles, especially carboxylic acids. Given the photoreactions, ...
Both BrN3 and IN3 find use in synthesis a convenient way to make azidiridines and azirines. The chlorine, bromine, and iodine ...
The Neber rearrangement offers an alternative to electrophilic amination through the intermediacy of an azirine. The wide ...
Hassner's group pioneered in methodology for synthesis of small ring heterocycles such as aziridines, azirines, azetines, as ...
Azirines can also be synthesized from the addition product by adding base to eliminate HI, giving a vinyl azide CH2=CHN3 which ... undergoes thermolysis to form an azirine. Further radical modes of reactivity include radical substitutions on weak C-H bonds ...
Added base forms a carbanion which displaces the tosylate group in a nucleophilic displacement to an azirine and added water ...
Certain N-substituted azirines with electron withdrawing groups on both carbons form azomethine ylides in an electrocyclic ...
The molecular formula C2H3N (molar mass: 41.05 g/mol, exact mass: 41.0265 u) may refer to: Acetonitrile (MeCN) Azirine Methyl ...
2H-Azirines can be considered strained imines and are isolable. 2H-Azirine is most often obtained by the thermolysis of vinyl ... An azirine is an intermediate in the Neber rearrangement. Dysidazirine, one of only a few naturally-occurring azirines Teresa M ... There are two isomers of azirine: 1H-Azirines with a carbon-carbon double bond are not stable and rearrange to the tautomeric ... Azirine can be generated during photolysis of isoxazole. Due to the weak N-O bond, the isoxazole ring tends to collapse under ...
The aliphatic 2H-azirine, methyl 3-methyl-2H-azirine-2-carboxylate (MMAC), has been synthesized and its monomeric form ... Very interestingly, the C-N bond photocleavage, which is unusual for aliphatic 2H-azirines, was found to be preferred over the ... Methyl 3-Methyl-2H-azirine-2-carboxylate Photochemistry Studied by Matrix-isolation ... generally favored in 2H-azirines C-C bond breakage. This behavior is attributed to the presence in the molecule of the electron ...
A more feasible route (Figure 2) involves the sole approach of the N1 atom in TMSN3 on the mentioned azirine carbon to give the ... Namely, the additional phenyl ring in 2 acts as an electron-acceptor and extracts the electron density from the azirine ring, ... The next sequence converts the 2-iodo-2H-azirine intermediate IN3 into its 2-azide analogue IN5, which our calculations show is ... The last conversion of the 2-azide-2H-azirine intermediate IN5 into the final nitriles represents the overall rate-limiting ...
Photochemistry of Matrix Isolated Methyl 3-Methyl 2H-Azirine-2-Carboxylate Studied by FT-IR and DFT Methods ... Unusual photochemical C-N Bond Cleavage in the novel Methyl 2-Chloro-3-Methyl-2H-Azirine-2-Carboxylate ...
H. Schmid). His research work during the habilitation was focused on the chemistry of 2H-azirines. He became lecturer at the ... Institute of Organic Chemistry of the University of Zuerich in 1980 with the habilitation thesis 3-Amino-2H-azirines, New ...
... azirines (str. 667-682) ...
... photocycloaddition of azirines to C=C, [2+2] photocycloaddition of triazinones to C=C, [3+2] photocycloaddition of pyridazines ...
"Studies on the Synthesis of Nitrogen Heterocycles via Cycloaddition and Reactivity of 2H-Azirines" (TESE/DISSERTAÇÃO) ... Pinho E Melo, T.M.V.D.; Cardoso, A.L.; Gomes, C.S.B.; Rocha Gonsalves, A.M.DA.. "2H-Azirines as dipolarophiles". Tetrahedron ... Cardoso, A.L.; Gomes, Clara S. B.; Pinho E Melo, T.M.V.D.; Rocha Gonsalves, A.M.DA.. "2H-Azirines as Dipolarophiles". Trabalho ... Gomes, Clara S. B.. "Studies on the Synthesis of Nitrogen Heterocycles via Cycloaddition and Reactivity of 2H-Azirines". ...
Effects of in-vitro treatment of boar spermatozoa with TEPA on the fertilization and development of pig eggs. - Texas A&M University (TAMU) Scholar profile, educations, publications, research, recent courses, and student works
Email me at this address if my answer is selected or commented on:Email me if my answer is selected or commented on ...
18. AZIRINES [ԱԶԻՐԻՆՆԵՐ] 4. AZAGUANINE [ԱԶԱԳՈՒԱՆԻՆ] 19. AZLOCILLIN [ԱԶԼՈՑԻԼԼԻՆ] 5. AZAPERONE [ԱԶԱՊԵՐՈՆ] 20. AZO COMPOUNDS [ ...
Azirines [D03.383.097]. *Aziridines [D03.383.097.217]. *Triethylenemelamine [D03.383.097.217.924]. *Triazines [D03.383.931] ...
Addition to Azirines. *Aziridines through Cyclization. *From Epoxides. *From 1,2-Aminoalcohols and 1,2-Aminohalides ...
Stereoselective 1,3-Dipolar Cycloaddition of a Nitrile Ylide Photochemically Generated from 2,3-Diphenyl-2H-azirine to ...
88 - Synthesis of New 2-Halo-2-(1H-tetrazol-5-yl)-2H-azirines via a Non-Classical Wittig Reaction. Ana L. Cardoso, Carmo Sousa ... 38 - Asymmetric Neber Reaction in the Synthesis of Chiral 2-(Tetrazol-5-yl)-2H- Azirines. Cláudia C. Alves, Carla Grosso, Pedro ... 240 - Reactivity of 2-halo-2H-azirines. 1. Reactions with nucleophiles. TMVDPE Melo, CSJ Lopes, AMDR Gonsalves, AM Beja, JA ...
3+2]-Cycloaddition of 2H-Azirines with Nitrosoarenes: Visible Light Promoted Synthesis of 2,5-Dihydro-1,2,4-Oxadiazoles ... 3+2] Cyclization/OxidativeAromtization Sequence via Photoredox Catalysis: One-Pot Synthesis of Oxazolesfrom 2H-Azirines and ...
The photodenitrogenation of vinyl azides to 2H-azirines by using a photoflow reactor is reported and compared with thermal ... formation of 2H-azirines. Photochemically, the ring of the 2H-azirines was opened to yield the ... ...
Azirines*Mitomycins: 9*Mitomycin: 6200*mitomycin C-dextran: 11. *MiPE protocol: 8 ...
AZIRINE CONTAINING COMPOUNDS AS ANTI-ANGIOGENESIS AGENTS AND PREPARATION THEREOF CSIR Reference Number: 0105NF2019 ... Particularly the present invention relates to azirine containing compounds of formula I Formula I wherein R1 is selected from ... Abstract: The present invention relates to azirine containing compounds useful as anti-angiogenesis agents and preparation ...
"Cu(II)-catalyzed domino reaction of 2H-azirines with diazotetramic and diazotetronic acids. Synthesis of 2-substituted 2H-1,2,3 ...
... azirines, diazepin-2-ones, carbazolones, quinolin-2-ones, 1,4-benzodiazepines, spirooxindoles, etc under mild reaction ...
Structure, spectroscopic signatures, and formation of hydroxy-azirine: a potential interstellar prebiotic molecule. REDONDO P ...
Azirinium ylides generated from 2,3-di- and 2,2,3-triaryl-substituted azirines give rise to only 2-azabuta-1,3-dienes and/or 2H ... An unusual N-C2 azirine bond cleavage, initiated by a copper enolate, was rationalized in terms of a free radical reaction ... A stereoselective and high-yield synthesis of hexahydropyrrolo[3,4-b]pyrroles from tetramic acids and 2H-azirines under Cu(I)- ... "Azirinium ylides from ?-diazoketones and 2H-azirines on the route to 2H-1,4-oxazines: three-membered ring opening vs 1,5- ...
Rh(III)-Catalyzed C-H Activation and [4+1+1] Sequential Cyclization Cascade to Give Highly Fused Indano[1,2-b]azirines. ... These fused indano[1,2-b]azirine derivatives could also be further transformed into intriguing privileged drug scaffolds. ... azirine frameworks in good yields with a broad range of substrates under mild reaction conditions. More intriguingly, a [4+1+1 ...
Azirines, Thiiranes, Thiirenes, Volume 42 1983. Base Isolation - Final ReportEVALUATION OF PUSHOVER ANALYSIS PROCEDURESAn ...
Amino Acid Sequence, Animals, Azirines, Binding Sites, Carcinoma, Squamous Cell, Cell Differentiation, Cell Line, Tumor, Cell ...
Unsaturated Azacyclopropanes use Azirines Unsaturated Dietary Fat use Dietary Fats, Unsaturated Unsaturated Dietary Fats use ...
Aziridines Azirines Cyclopropanes Diaziridines Oxaziridines Oxiranes Thiiranes Four-Membered Rings. Azetidines Cyclobutanes ...
Aziridines Azirines Cyclopropanes Diaziridines Oxaziridines Oxiranes Thiiranes Four-Membered Rings. Azetidines Cyclobutanes ...
Compounds based on a 7-membered heterocyclic ring including an oxygen. They can be considered a medium ring ether. A natural source is the MONTANOA plant genus. Some dibenzo-dioxepins, called depsidones, are found in GARCINIA plants ...
  • 2H-Azirine is most often obtained by the thermolysis of vinyl azides. (wikipedia.org)
  • The photodenitrogenation of vinyl azides to 2H-azirines by using a photoflow reactor is reported and compared with thermal formation of 2H-azirines. (uni-hannover.de)
  • A wide range of electron-poor 4-bromo-/4-chloro-2-azabuta-1,3-dienes were synthesized by the Rh2(OAc)4-catalyzed reaction of diazo esters and diazo ketones with methyl 2-halo-2H-azirine-2-carboxylates. (spbu.ru)
  • Cu(II)-catalyzed domino reaction of 2 H -azirines with diazotetramic and diazotetronic acids. (spbu.ru)
  • A stereoselective and high-yield synthesis of hexahydropyrrolo[3,4-b]pyrroles from tetramic acids and 2H-azirines under Cu(I)-NHC catalysis is developed. (spbu.ru)
  • Very interestingly, the C-N bond photocleavage, which is unusual for aliphatic 2H-azirines, was found to be preferred over the generally favored in 2H-azirines C-C bond breakage. (conicet.gov.ar)
  • An unusual N-C2 azirine bond cleavage, initiated by a copper enolate, was rationalized in terms of a free radical reaction mechanism. (spbu.ru)
  • Azirines are three-membered heterocyclic unsaturated (i.e. they contain a double bond) compounds containing a nitrogen atom and related to the saturated analogue aziridine. (wikipedia.org)
  • There are two isomers of azirine: 1H-Azirines with a carbon-carbon double bond are not stable and rearrange to the tautomeric 2H-azirine, a compound with a carbon-nitrogen double bond. (wikipedia.org)
  • Due to the weak N-O bond, the isoxazole ring tends to collapse under UV irradiation, rearranging to azirine. (wikipedia.org)
  • Strained azirinium ylides derived from 2H-azirines and α-diazoketones under Rh(II)-catalysis can undergo either irreversible ring opening across the N-C2 bond to 2-azabuta-1,3-dienes that further cyclize to 2H-1,4-oxazines or reversibly undergo a 1,5-cyclization to dihydroazireno[2,1-b]oxazoles. (spbu.ru)
  • Dysidazirine, one of only a few naturally-occurring azirines Teresa M. V. D. Pinho e Melo and Antonio M. d'A. (wikipedia.org)
  • Although most work has been concentrated on thermal and photochemical cycloaddition reactions of 1-azirines, reactions which proceed via C-N-, N=C-, or C-C-bond cleavage are included. (biu.ac.il)
  • An azirine is an intermediate in the Neber rearrangement. (wikipedia.org)
  • Preparation of 2-(phosphoranylideneamino)acrylaldehydes, novel formyl-substituted (vinylimino)phosphoranes, was accomplished by the reaction of formyl-2H-azirines with triphenylphosphine. (elsevierpure.com)