Cyclobutanes are saturated hydrocarbons consisting of a four-carbon ring with only carbon-carbon sigma bonds, making up the smallest cycloalkane ring that can adopt a puckered conformation to alleviate angle strain. (25 words)

Synthesis and evaluation of [18F]1-amino-3-fluorocyclobutane-1-carboxylic acid to image brain tumors. (1/266)

We have developed a new tumor-avid amino acid, 1-amino-3-fluorocyclobutane-1-carboxylic acid (FACBC), labeled with 18F for nuclear medicine imaging. METHODS: [18F]FACBC was prepared with high specific activity (no carrier added [NCA]) and was evaluated for its potential in tumor localization. A comparative study was performed for [18F]FACBC and [18F]2-fluorodeoxyglucose (FDG) in which the uptake of each agent in 9L gliosarcoma (implanted intracerebrally in Fisher 344 rats) was measured. In addition, the first human PET study of [18F]FACBC was performed on a patient with residual glioblastoma multiforme. Quantitative brain images of the patient were obtained by using a Siemens 921 47-slice PET imaging system. RESULTS: In the rat brain, the initial level of radioactivity accumulation after injection of [18F]FACBC was low (0.11 percentage injected dose per gram [%ID/g]) at 5 min and increased slightly to 0.26 %ID/g at 60 min. The tumor uptake exhibited a maximum at 60 min (1.72 %ID/g), resulting in a tumor-to-brain ratio increase of 5.58 at 5 min to 6.61 at 60 min. In the patient, the uptake of [18F]FACBC in the tumor exhibited a maximum concentration of 146 nCi/mL at 35 min after injection. The uptake of radioactivity in the normal brain tissue was low, 21 nCi/mL at 15 min after injection, and gradually increased to 29 nCi/mL at 60 min after injection. The ratio of tumor to normal tissue was 6 at 20 min after injection. The [18F]FACBC PET scan showed intense uptake in the left frontal region of the brain. CONCLUSION: The amino acid FACBC can be radiofluorinated for clinical use. [18F]FACBC is a potential PET tracer for tumor imaging.  (+info)

Thermogenic effects of sibutramine and its metabolites. (2/266)

1. The thermogenic activity of the serotonin and noradrenaline reuptake inhibitor sibutramine (BTS 54524; Reductil) was investigated by measuring oxygen consumption (VO2) in rats treated with sibutramine or its two pharmacologically-active metabolites. 2. Sibutramine caused a dose-dependent rise in VO2, with a dose of 10 mg kg(-1) of sibutramine or its metabolites producing increases of up to 30% that were sustained for at least 6 h, and accompanied by significant increases (0.5-1.0 degrees C) in body temperature. 3. Based on the accumulation in vivo of radiolabelled 2-deoxy-[3H]-glucose, sibutramine had little or no effect on glucose utilization in most tissues, but caused an 18 fold increase in brown adipose tissue (BAT). 4. Combined high, non-selective doses (20 mg kg(-1)) of the beta-adrenoceptor antagonists, atenolol and ICI 118551, inhibited completely the VO2 response to sibutramine, but the response was unaffected by low, beta1-adrenoceptor-selective (atenolol) or beta2-adrenoceptor-selective (ICI 118551) doses (1 mg kg(-1)). 5. The ganglionic blocking agent, chlorisondamine (15 mg kg(-1)), inhibited completely the VO2 response to the metabolites of sibutramine, but had no effect on the thermogenic response to the beta3-adrenoceptor-selective agonist BRL 35135. 6. Similar thermogenic responses were produced by simultaneous injection of nisoxetine and fluoxetine at doses (30 mg kg(-1)) that had no effect on VO2 when injected individually. 7. It is concluded that stimulation of thermogenesis by sibutramine requires central reuptake inhibition of both serotonin and noradrenaline, resulting in increased efferent sympathetic activation of BAT thermogenesis via beta3-adrenoceptor, and that this contributes to the compound's activity as an anti-obesity agent.  (+info)

Structural consequences of anesthetic and nonimmobilizer interaction with gramicidin A channels. (3/266)

Although interactions of general anesthetics with soluble proteins have been studied, the specific interactions with membrane bound-proteins that characterize general anesthesia are largely unknown. The structural modulations of anesthetic interactions with synaptic ion channels have not been elucidated. Using gramicidin A as a simplified model for transmembrane ion channels, we have recently demonstrated that a pair of structurally similar volatile anesthetic and nonimmobilizer, 1-chloro-1,2,2-trifluorocyclobutane (F3) and 1,2-dichlorohexafluorocyclobutane (F6), respectively, have distinctly different effects on the channel function. Using high-resolution NMR structural analysis, we show here that neither F3 nor F6 at pharmacologically relevant concentrations can significantly affect the secondary structure of the gramicidin A channel. Although both the anesthetic F3 and the nonimmobilizer F6 can perturb residues at the middle section of the channel deep inside the hydrophobic region in the sodium dodecyl sulfate micelles, only F3, but not F6, can significantly alter the chemical shifts of the tryptophan indole N-H protons near the channel entrances. The results are consistent with the notion that anesthetics cause functional change of the channel by interacting with the amphipathic domains at the peptide-lipid-water interface.  (+info)

Comparison of the potassium channel openers, WAY-133537, ZD6169, and celikalim on isolated bladder tissue and In vivo bladder instability in rat. (4/266)

The effects of the ATP-dependent potassium channel agonists ZD6169, celikalim, and WAY-133537 on bladder contractile function were examined in vitro on isolated bladder strips and in vivo on spontaneous bladder contractions. All three compounds produced a concentration-dependent relaxation of isolated rat detrusor strips (IC50 values = 0.93, 0.03, and 0.09 microM, respectively for ZD6169, celikalim, and WAY-133537. Contractile inhibition by all three compounds was fully reversed by 6 microM glyburide. These compounds also effectively inhibited spontaneous bladder contractions in the rat hypertrophied bladder model of detrusor instability. We also examined the electrophysiological properties of WAY-133537 on isolated rat bladder detrusor myocytes. Myocytes had an average resting membrane potential of -40 mV. Under patch current-clamp conditions, WAY-133537 (0.3 and 1.0 microM, n = 4-5) produced a significant hyperpolarization of 21 and 26 mV, respectively. Hyperpolarization was reversed by the addition of 5 microM glyburide. In patch voltage-clamp studies, WAY-133537 (0.3 microM, n = 3) significantly increased outward current in response to both voltage step and ramp protocols consistent with activation of the ATP-dependent potassium channel. In the detrusor instability model, WAY-133537 and celikalim had similar oral potencies (ED50 = 0.13 and 0.3 mg/kg, respectively), whereas ZD6169 was less potent (ED50 = 2.4 mg/kg). The antihypertensive agent celikalim exerted effects on the bladder at doses that significantly reduced systemic blood pressure. In contrast, both WAY-133537 and ZD6169 inhibited bladder hyperactivity at doses that produced minimal changes in both mean arterial blood pressure and heart rate. These data suggest that both WAY-133537 and ZD6169 may be useful in the treatment of bladder instability at doses associated with minimal hemodynamic side effects.  (+info)

Successful treatment of alopecia areata-like hair loss with the contact sensitizer squaric acid dibutylester (SADBE) in C3H/HeJ mice. (5/266)

A type of hair loss closely resembling human alopecia areata has been described in C3H/HeJ mice. In order to test the assumed analogy with human alopecia areata, we investigated the efficacy of treatment with the contact allergen squaric acid dibutylester. In 12 C3H/HeJ mice with alopecia areata an allergic contact dermatitis was induced and elicited weekly on one side of the back by topical applications of squaric acid dibutylester. Overt hair regrowth was observed only on the treated side of the back in nine of 12 mice. Histopathologic examination revealed a change in the distribution of the inflammatory infiltrate from a dense perifollicular lymphocytic infiltrate around the mid and lower regions of hair follicles in untreated skin to a uniform presence in the upper dermis in treated skin. Immunohistomorphometric studies revealed that treatment with squaric acid dibutylester increased the CD4+/CD8+ ratio from approximately 1:2 in untreated alopecia areata to 1:1 in treated alopecia areata. Additional immunohistochemical investigations showed an aberrant expression of major histocompatibility complex class I, major histocompatibility complex class II and intercellular adhesion molecule 1 on keratinocytes of the mid and lower parts of hair follicles in untreated alopecia areata. In successfully treated skin ectopic major histocompatibility complex class I and II expression was clearly reduced, whereas intercellular adhesion molecule 1 expression showed only minor changes. In conclusion, alopecia areata-like hair loss in C3H/HeJ mice responded to treatment with the contact sensitizer squaric acid dibutylester analogous to human alopecia areata. Moreover, successful treatment changes the aberrant expression of major histocompatibility complex class I and II in a way similar to that observed in human alopecia areata. These observations support the concept that alopecia areata-like hair loss in C3H/HeJ mice can be utilized as an appropriate model for the study of human alopecia areata.  (+info)

Distinctly different interactions of anesthetic and nonimmobilizer with transmembrane channel peptides. (6/266)

Although it plays no clinical role in general anesthesia, gramicidin A, a transmembrane channel peptide, provides an excellent model for studying the specific interaction between volatile anesthetics and membrane proteins at the molecular level. We show here that a pair of structurally similar volatile anesthetic and nonimmobilizer (nonanesthetic), 1-chloro-1,2,2-trifluorocyclobutane (F3) and 1, 2-dichlorohexafluorocyclobutane (F6), respectively, interacts differently with the transmembrane peptide. With 400 microM gramicidin A in a vesicle suspension of 60 mM phosphatidylcholine-phosphatidylglycerol (PC/PG), the intermolecular cross-relaxation rate constants between (19)F of F3 and (1)H in the chemical shift regions for the indole and backbone amide protons were 0.0106 +/- 0.0007 (n = 12) and 0.0105 +/- 0.0014 (n = 8) s(-1), respectively. No cross-relaxation was measurable between (19)F of F6 and protons in these regions. Sodium transport study showed that with 75 microM gramicidin A in a vesicle suspension of 66 mM PC/PG, F3 increased the (23)Na apparent efflux rate constant from 149.7 +/- 7.2 of control (n = 3) to 191.7 +/- 12.2 s(-1) (n = 3), and the apparent influx rate constant from 182.1 +/- 15.4 to 222.8 +/- 21.7 s(-1) (n = 3). In contrast, F6 had no effects on either influx or efflux rate. It is concluded that the ability of general anesthetics to interact with amphipathic residues near the peptide-lipid-water interface and the inability of nonimmobilizer to do the same may represent some characteristics of anesthetic-protein interaction that are of importance to general anesthesia.  (+info)

Studies on the role of serotonin receptor subtypes in the effect of sibutramine in various feeding paradigms in rats. (7/266)

The effect of the 5-hydroxytryptamine (5-HT) and noradrenaline (NA) reuptake inhibitor sibutramine was studied in food deprived, neuropeptide Y (NPY)- or muscimol-injected rats. Sibutramine dose-dependently reduced feeding caused by food-deprivation (ED50 = 5.1+/-0.8 mg kg(-1)) or by NPY injection into the paraventricular nucleus of the hypothalamus (ED50 = 6.0+/-0.5 mg kg(-1)). The increase in food intake caused by muscimol injected into the dorsal raphe was not modified by sibutramine (1-10 mg kg(-1)). The hypophagic effect of 5.1 mg kg(-1) sibutramine in food-deprived rats was studied in rats pretreated with different serotonin receptor antagonists. Metergoline (non-selective, 0.3 and 1.0 mg kg(-1)), ritanserin (5-HT2A/2C, 0.5 and 1.0 mg kg(-1)) and GR127935 (5-HT1B/1D), 0.5 and 1.0 mg kg(-1)) did not modify the hypophagic effect of sibutramine, while SB206553 (5-HT2B/2C, 5 and 10 mg kg(-1)) slightly but significantly reduced it (Fint(2.53) = 3.4; P<0.05). The reduction in food intake caused by 6.0 mg kg(-1) sibutramine in NPY-injected rats was not modified by GR127935 (1.0 mg kg(-1)). The results suggest that, with the possible exception of a partial involvement of 5-HT2B/2C receptors in sibutramine's hypophagia in food-deprived rats, 5-HT1 and 5-HT2 receptor subtypes do not play an important role in the hypophagic effect of sibutramine, at least in the first 2 h after injection.  (+info)

Subtype-selective inhibition of [methyl-3H]-N-methylscopolamine binding to muscarinic receptors by alpha-truxillic acid esters. (8/266)

Seven esters of alpha-truxillic acid have been synthesized: bis-3-piperidylpropyl ester and its quaternary bis-N-ethyl derivative, bis-N-diethylaminopropyl ester and its quaternary bis-N-methyl derivative, and bis-4-piperidylbutyl ester and its quaternary bis-N-methyl and bis-N-ethyl derivatives. All esters inhibited the specific binding of muscarinic receptor antagonist [methyl-3H]-N-methylscopolamine ([3H]-NMS) to muscarinic receptors in membranes of CHO cell lines stably expressing the human gene for the M1, M2, M3 or M4 subtype of muscarinic receptors. All esters displayed the highest potency at the M2 and the lowest potency at the M3 receptor subtype. In experiments performed on the M2 muscarinic receptor subtype, the affinity between the receptors and the esters was greatly increased when the concentration of ions was diminished. The highest affinities were found for the tertiary bis-3-piperidylpropyl and bis-4-piperidylbutyl aminoesters (equilibrium dissociation constants of 52 and 179 pM, respectively, in the low ionic strength medium). All investigated esters slowed down the dissociation of [3H]-NMS from the M2 muscarinic receptor subtype. [3H]-NMS dissociation from the M1, M3 and M4 muscarinic receptor subtypes was investigated in experiments with the bis-4-piperidylbutyl aminoester and also found to be decelerated. It is concluded that the esters of alpha-truxillic acid act as M2-selective allosteric modulators of muscarinic receptors and that, by their potency, the tertiary bis-3-piperidylpropyl and bis-4-piperidylbutyl aminoesters surpass the other known allosteric modulators of these receptors.  (+info)

Cyclobutanes are a class of organic compounds that contain a four-membered carbon ring. The carbons in this ring are bonded to each other in a cyclic arrangement, forming a square-like structure. These compounds can be found naturally or synthesized in the laboratory and play important roles in various chemical reactions and biological processes.

Cyclobutanes are relatively uncommon in nature due to the strain associated with having four carbons in a small ring. This strain makes the molecules more reactive, which can lead to interesting chemical properties. For example, cyclobutanes can undergo ring-opening reactions when exposed to heat or light, leading to the formation of new chemical bonds and the release of energy.

In biology, cyclobutane rings are found in certain types of DNA damage, such as those caused by ultraviolet (UV) radiation. These damages can lead to mutations and may contribute to the development of skin cancer. However, cells have mechanisms for repairing this type of DNA damage, helping to prevent these negative outcomes.

Overall, while cyclobutanes are relatively simple molecules, they have important implications in chemistry and biology, making them a fascinating area of study.

Derivatives of cyclobutane are called cyclobutanes. Cyclobutane itself is of no commercial or biological significance, but more ... As such, cyclobutane is unstable above about 500 °C. The four carbon atoms in cyclobutane are not coplanar; instead, the ring ... Cyclobutane is a cycloalkane and organic compound with the formula (CH2)4. Cyclobutane is a colourless gas and is commercially ... 1,4-Dihalobutanes convert to cyclobutanes upon dehalogenation with reducing metals. Cyclobutane was first synthesized in 1907 ...
"Fluorinated Cyclobutanes and Their Derivatives". In Zvi Rappoport; Joel F. Liebman (eds.). The Chemistry of Cyclobutanes. ...
"Fluorinated Cyclobutanes and Their Derivatives". In Zvi Rappoport; Joel F. Liebman (eds.). The Chemistry of Cyclobutanes. ...
Rappoport, Zvi; Liebman, Joel F. (2005). The Chemistry of Cyclobutanes. John Wiley & Sons. ISBN 9780470864012. Oda, Masaji; ...
The final cyclobutane is formed by a Wolff rearrangement, and the alkyl chain is installed by a Wittig olefination. In 2016, ... UV irradiation of the solid produces the targeted [n]ladderane, with the C=C bonds reacting to form the fused cyclobutane ... In chemistry, a ladderane is an organic molecule containing two or more fused cyclobutane rings. The name arises from the ... Ladderanes with lengths up to 13 cyclobutane rings have been synthesized by Mehta and coworkers. This process involves the in ...
Cyclobutane Cyclobutadiene Cyclobutyne Squaric acid J. Salaün; A. Fadel (1986). "Cyclobutene". Org. Synth. 64: 50. doi:10.15227 ... David M. Lemal; Xudong Chen (2005). "Fluorinated Cyclobutanes and Their Derivatives". In Zvi Rappoport; Joel F. Liebman (eds ... The Chemistry of Cyclobutanes. PATAI'S Chemistry of Functional Groups. pp. 955-1029. doi:10.1002/0470864028.ch21. ISBN ...
Cava, M. P.; Deana, A. A.; Muth, K. (1959). "Condensed Cyclobutane Aromatic Compounds. VIII. The Mechanism of Formation of 1,2- ...
M. P. Cava, J. P. VanMeter (1969). "Condensed cyclobutane aromatic compounds. XXX. Synthesis of some unusual 2,3- ...
However, osmium coordination complexes containing cyclobutyne have been synthesized.[which?] Cyclobutene Cyclobutane Hopf, ...
Cava, M. P.; Deana, A. A.; Muth, K. (1959). "Condensed Cyclobutane Aromatic Compounds. VIII. The Mechanism of Formation of 1,2- ...
Setlow, R. B. (1966). "Cyclobutane-type pyrimidine dimers in polynucleotides". Science. 153 (734): 379-386. Bibcode:1966Sci... ...
Lindner, Patrick E.; Correa, Ricardo A.; Gino, James; Lemal, David M. (1996-01-01). "Novel Keto−Enol Systems: Cyclobutane ...
In his early pre-ETH period, his work included structure studies of cyclobutane, of ferrocene with the first description of its ... Dunitz, J. D.; Schomaker, V. (1952). "The Molecular Structure of Cyclobutane" (PDF). The Journal of Chemical Physics. 20 (11): ...
A cyclobutane pyrimidine dimer (CPD) contains a four membered ring arising from the coupling of the two double-bonded carbons ... Specifically, adjacent thymines or cytosines in DNA will form a cyclobutane ring when joined together and cause a distortion in ... Two common UV products are cyclobutane pyrimidine dimers (CPDs) and 6-4 photoproducts. These premutagenic lesions alter the ... Setlow RB (July 1966). "Cyclobutane-type pyrimidine dimers in polynucleotides". Science. 153 (3734): 379-386. Bibcode:1966Sci ...
Roberts, John D.; Sharts, Clay M. (2011). "Cyclobutane Derivatives from Thermal Cycloaddition Reactions". Organic Reactions. pp ...
For many years the structure of dicyclopentadiene was thought to feature a cyclobutane ring as the fusion between the two ... Roberts, John D.; Sharts, Clay M. (2011). "Cyclobutane Derivatives from Thermal Cycloaddition Reactions". Organic Reactions. pp ...
Reaction of α,α′-dibromoadipic acid with sodium cyanide in ethanol yields the cyano cyclobutane: In the so-called Franchimont ... 6, p. 307 Reynold C. Fuson; Oscar R. Kreimeier & Gilbert L. Nimmo (1930). "Ring Closures in the Cyclobutane Series. II. ...
When irradiated by UV-light, alkenes dimerize to give cyclobutanes. Another example is the Schenck ene reaction, in which ...
"Structure-Mechanochemical Activity Relationships for Cyclobutane Mechanophores". Journal of the American Chemical Society. 133 ...
CYCLOBUTANE- TYPE PYRIMIDINE DIMERS IN POLYNUCLEOTIDES, R. B. Setlow, Science 1966 Vol. 153, p. 379, DOI: 10.1126/science. ... These reactions include cis-trans isomerization, cycloaddition to other (ground state) alkene to give cyclobutane derivatives. ... DNA: photodimerization leading to cyclobutane pyrimidine dimers. Examples of photochemical organic reactions are electrocyclic ...
This species is electronically related to cyclobutane. Theory suggest that the diatomic aluminium monobromide condenses to a ...
Cyclopropenes, aziridines and cyclobutanes may be formed in a similar manner. Carbon acids which can be deprotonated by sodium ...
For simple non-planar cyclobutanes, dihedral angles range from 19 to 31°. CBDO's cis isomer crystallizes as two conformers with ... 1867-1870.doi:10.1107/S0567740876006559 Margulis, T.R. "Planar Cyclobutanes: Structure of 2,2,4,4-Tetramethylcyclobutane-trans- ...
... to structurally complex cyclobutanes. Asymmetric Hydrocyanation The RajanBabu group developed methodology in the area of ... "Tandem catalysis for asymmetric coupling of ethylene and enynes to functionalized cyclobutanes". Science. 361 (6397): 68-72. ...
Cycloaddition provides a cyclobutane ring connecting two fullerene molecules. Main-chain polymers are characterized by the ...
Sinninghe, Damste (2002). "Linearly concatenated cyclobutane lipids form a dense bacterial membrane". Nature. 419 (6908): 708- ... which contain a series of cyclobutane ring structures. However, all other membranes within anammox bacteria are similar to ...
Its DNA damage effect produces cyclobutane-type pyrimidine dimers. Besides the direct effects, UV-C also induces resistance ...
Cannistraro VJ, Pondugula S, Song Q, Taylor JS (2015). "Rapid deamination of cyclobutane pyrimidine dimer photoproducts at TCG ... the photoproduct is typically the cyclobutane pyrimidine dimer (CPD). Specificity for C>T appears to be due to the million-fold ...
Structurally, the molecule consists of cyclopropane fused to cyclobutane. The synthesis of molecules containing multiple ... Cyclobutanes, Hydrocarbons, Cyclopropanes, Bicycloalkanes, All stub articles, Hydrocarbon stubs). ...
Scheerer P, Zhang F, Kalms J, von Stetten D, Krauß N, Oberpichler I, Lamparter T (May 2015). "The class III cyclobutane ... Thiagarajan V, Byrdin M, Eker AP, Müller P, Brettel K (June 2011). "Kinetics of cyclobutane thymine dimer splitting by DNA ... The more common covalent linkage involves the formation of a cyclobutane bridge. Photolyases have a high affinity for these ... Teranishi, M., Nakamura, K., Morioka, H.,Yamamoto, K. and Hidema, J. (2008). "The native cyclobutane pyrimidine dimer ...
Derivatives of cyclobutane are called cyclobutanes. Cyclobutane itself is of no commercial or biological significance, but more ... As such, cyclobutane is unstable above about 500 °C. The four carbon atoms in cyclobutane are not coplanar; instead, the ring ... Cyclobutane is a cycloalkane and organic compound with the formula (CH2)4. Cyclobutane is a colourless gas and is commercially ... 1,4-Dihalobutanes convert to cyclobutanes upon dehalogenation with reducing metals. Cyclobutane was first synthesized in 1907 ...
Enantioselective Synthesis of Cyclobutanes. Author: ChemistryViews. Chiral cyclobutanes are found, e.g., in natural products ... The regio- and enantioselective synthesis of cyclobutane derivatives can be challenging. One approach to this is the visible- ... Enantioselective Synthesis of Cyclobutane Derivatives via Cascade Asymmetric Allylic Etherification/[2 + 2] Photocycloaddition, ... New directing-group-free enantioselective [2 + 2] photocycloaddition reactions that give chiral cyclobutanes would be useful. ...
... cyclobutane-1-carboxylic acid , MF: C7H10O4 , MW: 158.15 ... cis-2-(Methoxycarbonyl)cyclobutane-1-carboxylic acid * Alt Name ...
Description of cyclobutane. Cyclobutane molecular model and properties. ... Cyclobutane is not flat, one of its carbons comes out about 25º from the plane formed by the other three carbons. This ...
Cyclobutane. CH2(CH2CH2CH2) (g). 52.34. 27.80. ± 0.41. kJ/mol. 56.1063 ±. 0.0032. 287-23-0*0. ... Cyclobutane. CH2(CH2CH2CH2) (l). 3.92. ± 0.41. kJ/mol. 56.1063 ±. 0.0032. 287-23-0*590. ...
You are viewing an interactive 3D depiction of the molecule 1-[(R)-cyclobutylsulfinyl]-1-methyl-cyclobutane (C9H16OS) from the PQR.
You are viewing an interactive 3D depiction of the molecule (1R)-1-methyl-2-(1-methylbutylidyne)cyclobutane (C10H18) from the PQR.
Cyclobutane Derivatives from Thermal Cycloaddition Reactions. Brought to you by the Organic Reactions Wiki, the online ... Retrieved from "http://organicreactions.org/index.php?title=Cyclobutane_Derivatives_from_Thermal_Cycloaddition_Reactions&oldid= ...
Chemical and physical properties of Cyclobutane-d8. ... Find more compounds similar to Cyclobutane-d8.. Sources. * ...
GTD-5000 Sampling Gas Detector Octafluoro cyclobutane (C4F8) 0-200 ppm (*PY-1000) - Gas Detection Australia provides customised ... GTD-5000 Sampling Gas Detector Octafluoro cyclobutane (C4F8) 0-200 ppm (*PY-1000) quantity. ... GTD-5000 Sampling Gas Detector Octafluoro cyclobutane (C4F8) 0-200 ppm (*PY-1000). ...
Littman, L., Tokar, C., Venkatraman, S., Roon, R. J., Koerner, J. F., Robinson, M. B., & Johnson, R. L. (1999). Cyclobutane ... Cyclobutane quisqualic acid analogues as selective mGluR5a metabotropic glutamic acid receptor ligands. Journal of medicinal ... Cyclobutane quisqualic acid analogues as selective mGluR5a metabotropic glutamic acid receptor ligands. In: Journal of ... The conformationally constrained cyclobutane analogues of quisqualic acid (Z)- and (E)-1-amino-3-[2-(3,5-dioxo-1,2,4- ...
Enantioselective Synthesis of Cyclobutanes. October 3, 2023. News. Improved Synthesis Route for Lifitegrast. October 1, 2023. ...
BRENDA - The Comprehensive Enzyme Information System
Thymine Dimerization in DNA Model Systems: Cyclobutane Photolesion Is Predominantly Formed via the Singlet Channel ... Thymine Dimerization in DNA Model Systems: Cyclobutane Photolesion Is Predominantly Formed via the Singlet Channel ...
Dimeric cyclobutane formation under continuous flow conditions using Organophotoredox‐catalysed [2+2] cycloaddition ... The cyclobutane dimers could be isolated in higher chemical yields under continuous flow conditions and reaction times were ... Dimeric Cyclobutane FormationOrganophotoredox-Catalysed [2+2] CycloadditionOrganic Chemistry not elsewhere classified ... Radical-cation-initiated dimerization of electron rich alkenes is an expedient method for the synthesis of cyclobutanes. By ...
Cyclobutane pyrimidine dimers. *(6-4) photoproducts. *Chemiexcitation. *Damaged oligonucleotides structure and dynamics ...
Direct Photochemical Cleavage of the Cyclobutane Ring in Bicyclo[4.2.0]octane on 185nm Irradiation in Solution. ...
Cyclobutane 2 led to modest inhibition of the murine P388 leukemia cell line. ... Cyclobutane 2 led to modest inhibition of the murine P388 leukemia cell line.", ... Cyclobutane 2 led to modest inhibition of the murine P388 leukemia cell line. ... Cyclobutane 2 led to modest inhibition of the murine P388 leukemia cell line. ...
Cyclobutane-1, 1-dicarboxylic acid , RM3296-5G , HiMedia Laboratories Group: CHEMICALS Sub-Group: Specialty Chemicals ...
Cyclobutane-1,1-dicarboxylic acid monoamide. 0 out of 5. $0.00. Read more Add to wishlist ...
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Saner Poplata, Andreas Tröster, You-Quan Zou, and Thorsten Bach . Recent Advances in the Synthesis of Cyclobutanes by Olefin [2 ...
Derivatives of cyclobutane are called cyclobutanes.... has the carbon atoms in a puckered square with approximately 90-degree ... Cyclobutane is an organic compound with the formula 4. Cyclobutane is a colourless gas and commercially available as a ... Cyclobutane is an organic compound with the formula 4. Cyclobutane is a colourless gas and commercially available as a ... Cycloalkanes are classified into small, common, medium, and large cycloalkanes, where cyclopropane and cyclobutane are the ...
2 + 2]-Cycloreversion starrer Cyclobutane, Chem. Ber., 1988, 121, 1-9. [all data] ...
Cyclobutane-1,1-di. carboxylato(2-)-κ2. O1. ,O1. ]platinum diammonia. te ...
"No Strain, No Gain: Advances in the Synthesis and use of Cyclobutanes". ...
NMR and computational studies on the reactions of enamines with nitroalkenes that may pass through cyclobutanes. ACS Omega 4, ... Depending on the nature of the two reactants, either a cyclobutane or a dihydropyran is transiently formed (detected by 1H NMR ... 2a). To this effect, a sequence of (1) enamine condensation, (2) cyclobutane formation and (3) hydride shuttle ring ... the events of cyclobutane formation and the hydride shuttle deliver virtually enantiopure azabicyclic products ((+)-5a-(+)-5r). ...
Scheme 5: Oxidative SET-triggered rearrangement of vinyl cyclobutane 4. Conditions: 1.0 M LiClO4/CH3NO2, carb... ... Scheme 6: Unsuccessful rearrangement of cyclobutanes. Conditions: 1.0 M LiClO4/CH3NO2, carbon felt electrodes... ...
2. DNA Backbone Conformation in Cis-Syn Pyrimidine[ ]Pyrimidine Cyclobutane Dimers Broyde, Suse B.; Stellman, Steven D.; ...
The rate constant for the decomposition of cyclobutane is 2.08 × 10-2 s-1 at high temperatures. C4H8(g) → 2C2H4(g) How many ...
  • Derivatives of cyclobutane are called cyclobutanes. (wikipedia.org)
  • Cyclobutane itself is of no commercial or biological significance, but more complex derivatives are important in biology and biotechnology. (wikipedia.org)
  • The regio- and enantioselective synthesis of cyclobutane derivatives can be challenging. (chemistryviews.org)
  • Shu-Li You, Shanghai Institute of Organic Chemistry, University of the Chinese Academy of Sciences, and colleagues have developed a method for the synthesis of enantioenriched cyclobutane derivatives (oxa-[3,2,0]-bicyclic heptanes, general structure pictured) that proceeds in a cascade fashion. (chemistryviews.org)
  • The simplest members are cyclopropane (C3H6), cyclobutane (C4H8), cyclohexane (C6H12), and derivatives of these such as methylcyclohexane (C6H11CH3). (bvsalud.org)
  • Spivak G, Itoh T, Matsunaga T, Nikaido O, Hanawalt P, Yamaizumi M. Ultraviolet-sensitive syndrome cells are defective in transcription-coupled repair of cyclobutane pyrimidine dimers. (medlineplus.gov)
  • UV light, it turns out, may act via a "light" or a "dark" biochemical pathway to cause a type of DNA damage known as a cyclobutane pyrimidine dimer (CPD). (genengnews.com)
  • A copper hydride-catalyzed, enantioselective, intramolecular hydroalkylation of halide-tethered styrenes enables the synthesis of enantioenriched cyclobutanes, cyclopentanes, indanes, and six-membered N - and O -heterocycles. (organic-chemistry.org)
  • Recent Advances in the Synthesis of Cyclobutanes by Olefin [2 + 2] Photocycloaddition Reactions. (acs.org)
  • Radical-cation-initiated dimerization of electron rich alkenes is an expedient method for the synthesis of cyclobutanes. (lboro.ac.uk)
  • New directing-group-free enantioselective [2 + 2] photocycloaddition reactions that give chiral cyclobutanes would be useful. (chemistryviews.org)
  • Aliphatic three- and four-membered rings including cyclopropanes, cyclobutanes, oxetanes, azetidines and bicyclo[1.1.1]pentanes have been increasingly exploited in medicinal chemistry for their beneficial physicochemical properties and applications as functional group bioisosteres. (rsc.org)
  • citation needed] Cyclobutane photo dimers (CPD) are formed by photochemical reactions that result in the coupling of the C=C double bonds of pyrimidines. (wikipedia.org)
  • Chiral cyclobutanes are found, e.g., in natural products and bioactive compounds. (chemistryviews.org)
  • Cyclobutane-containing scaffolds in bioactive small molecules. (mpg.de)
  • Carboplatin is a popular anticancer drug that is derived from cyclobutane-1,1-dicarboxylic acid. (wikipedia.org)
  • abstract = "The conformationally constrained cyclobutane analogues of quisqualic acid (Z)- and (E)-1-amino-3-[2'-(3',5'-dioxo-1',2',4'- oxadiazolidinyl)]cyclobutane-1-carboxylic acid, compounds 2 and 3, respectively, were synthesized. (umn.edu)
  • One unusual example is pentacycloanammoxic acid, which is a ladderane composed of 5 fused cyclobutane units. (wikipedia.org)
  • The cyclobutane dimers could be isolated in higher chemical yields under continuous flow conditions and reaction times were reduced significantly compared to traditional batch reaction conditions. (lboro.ac.uk)
  • Equivalent puckered conformations interconvert: Despite the inherent strain, the cyclobutane motif is indeed found in nature. (wikipedia.org)
  • By merging organophotoredox catalysis and continuous flow technology, a batch versus continuous flow study has been performed providing a convenient synthetic route to an important carbazole cyclobutane material dimer 1,2-trans-dicarbazylcyclobutane (t-DCzCB) using only 0.1 mol % of an organophotoredox catalyst. (lboro.ac.uk)
  • citation needed] Cyclobutane photo dimers (CPD) are formed by photochemical reactions that result in the coupling of the C=C double bonds of pyrimidines. (wikipedia.org)
  • Those observations have led us to suggest that UV(S)S cells, like those from CS, are defective in transcription-coupled repair (TCR) of cyclobutane pyrimidine dimers (CPD). (nih.gov)
  • T4 PDG recognizes cis-syn-cyclobutane pyrimidine dimers caused by UV irradiation. (neb.com)
  • 6. Cyclobutane pyrimidine dimers are predominant DNA lesions in whole human skin exposed to UVA radiation. (nih.gov)
  • 8. Wavelength dependence of ultraviolet radiation-induced DNA damage as determined by laser irradiation suggests that cyclobutane pyrimidine dimers are the principal DNA lesions produced by terrestrial sunlight. (nih.gov)
  • 10. Photoreactivation of cyclobutane dimers and (6-4) photoproducts in the epidermis of the marsupial, Monodelphis domestica. (nih.gov)
  • 11. Differential repair of UVB-induced cyclobutane pyrimidine dimers in cultured human skin cells and whole human skin. (nih.gov)
  • 13. UVA1 induces cyclobutane pyrimidine dimers but not 6-4 photoproducts in human skin in vivo. (nih.gov)
  • 15. Biological consequences of cyclobutane pyrimidine dimers. (nih.gov)
  • 20. Apigenin prevents ultraviolet-B radiation induced cyclobutane pyrimidine dimers formation in human dermal fibroblasts. (nih.gov)
  • T4 endonuclease V has been shown to repair cyclobutane pyrimidine dimers resulting from DNA damage. (medscape.com)
  • At 24 hr after UVR, DNA photoproducts [cyclobutane pyrimidine dimers (CPDs) and 6-4 photoproducts (6-4PPs)] and apoptosis were measured using the enzyme-linked immunosorbent assay and the two-color TUNEL (terminal deoxynucleotide transferase dUTP nick end labeling) assay, respectively. (nih.gov)
  • the major DNA damage is cyclobutane pyrimidine dimers (CPDs) and 6-4 photoproducts (6-4PPs). (nih.gov)
  • Perspectives on Cyclobutane Pyrimidine Dimers-Rise of the Dark Dimers. (nih.gov)
  • Spivak G, Itoh T, Matsunaga T, Nikaido O, Hanawalt P, Yamaizumi M. Ultraviolet-sensitive syndrome cells are defective in transcription-coupled repair of cyclobutane pyrimidine dimers. (medlineplus.gov)
  • Flow cytometry assays demonstrated S-phase cell cycle arrest, reduced apoptosis levels and faster induction of cyclobutane pyrimidine dimers (CPD) lesions in carbaryl treated groups. (nih.gov)
  • Quantification of cyclobutane pyrimidine dimers (CPDs). (nih.gov)
  • Quantification of cyclobutane pyrimidine dimers (CPDs): fluorescence absorbance median analyzed by flow cytometry after 1 and 6 h of treatment. (nih.gov)
  • UVB irradiation can directly crosslink DNA at dipyrimidine sites to produce cyclobutane-pyrimidine dimers and (6-4) photoproducts. (dermatologytimes.com)
  • All cells show markedly reduced XPC mRNA, no detectable XPC protein and no repair of 6-4 photoproducts (6-4PP) and cyclobutane pyrimidine dimers (CPD). (nih.gov)
  • Rapid deamination of cyclobutane pyrimidine dimer photoproducts at TCG sites in a translationally and rotationally positioned nucleosome in vivo. (nih.gov)
  • Understanding the Mechanochemistry of Ladder-Type Cyclobutane Mechanophores by Single Molecule Force Spectroscopy. (stanford.edu)
  • We have recently reported a series of ladder-type cyclobutane mechanophores, polymers of which can transform from nonconjugated structures to conjugated structures and change many properties at once. (stanford.edu)
  • These multicyclic mechanophores, namely, exo-ladderane/ene, endo-benzoladderene, and exo-bicyclohexene-peri-naphthalene, have different ring structures fused to the first cyclobutane, significantly different free energy changes for ring-opening, and different stereochemistry. (stanford.edu)
  • One unusual example is pentacycloanammoxic acid, which is a ladderane composed of 5 fused cyclobutane units. (wikipedia.org)
  • Carboplatin is a popular anticancer drug that is derived from cyclobutane-1,1-dicarboxylic acid. (wikipedia.org)
  • Equivalent puckered conformations interconvert: Despite the inherent strain, the cyclobutane motif is indeed found in nature. (wikipedia.org)
  • Many methods exist for the preparation of cyclobutanes. (wikipedia.org)
  • SpiroChem designs and commercializes a large range of small-rings- (oxetane, azetidine, cyclobutane, thietane) and spirocycle-containing molecules for use in drug discovery. (ldorganisation.com)
  • Zur Kenntnis der Cyclobutanreihe" [On our knowledge of the cyclobutane series]. (wikipedia.org)
  • Purity:99.9% cyclobutane-1,2,3,4-tetracarboxylic dianhydride and diamine monomer are used for preparation a polyimide (PI), the type of polyimide has excellent electrical characteristics and optical type, with the material prepared the PI film, in addition to having a higher rate cast visible outside, and can withstand high temperatures thirty-four Baidu. (ydachem.com)