40628-41-9Relevant academic research and scientific papers
Controlled/ living reverse atom transfer radical polymerization of a monocyclic olefin, methyl 1-cyclobutenecarboxylate
Chen, Xiao-Ping,Sufi, Bilal A.,Padias, Anne Buyle,Hall Jr.
, p. 4277 - 4281 (2002)
ATRP of the first cyclic olefin, methyl 1-cyclobutenecarboxylate (MCBE), by addition polymerization in a well controlled/ living manner is described, along with a new practical method to synthesize MCBE. The polydispersity of poly(methyl 1-cyclobutenecarboxylate) (PMCBE) synthesized by a conventional ATRP initiation system was narrow (Mw/Mn = 1.1 - 1.4), but Mn was usually less than half of the theoretical number-average molecular weight. However, the polymerization of MCBE initiated by a reverse ATRP initiation system, AIBN/CuBr2/dNbpy, was well controlled; the rate of polymerization was first order in monomer, and the molecular weights of the polymers were close to the designed values with very narrow polydispersities (Mw/Mn = ～1.15). The obtained polymer PMCBE can be used as a macroinitiator to further polymerize a second monomer, such as styrene.
ALTERNATING RING-OPENING METATHESIS POLYMERIZATION
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, (2011/09/20)
The invention relates to the field of polymers and olefin polymerization, and more specifically olefin metathesis polymerization. The invention provides regioregular alternating polymers and methods of synthesizing such polymers.
Scope of the ring-opening metathesis polymerization (ROMP) reaction of 1-substituted cyclobutenes
Song, Airong,Lee, Jae Chul,Parker, Kathlyn A.,Sampson, Nicole S.
scheme or table, p. 10513 - 10520 (2010/09/17)
The reactivities of a series of 1-substituted cyclobutene derivatives (carboxylate esters, carboxamides, and carbinol esters) were investigated as substrates for ring-opening metathesis polymerization (ROMP) with [(H 2IMes)(3-Br-pyridine)2(Cl)2Ru=CHPh]. Both the secondary amides of 1-cyclobutenecarboxylic acid and the esters of 1-cyclobutene-1-methanol undergo polymerization. The secondary amides provide translationally invariant polymers (E-olefins). Although the carbinol esters yield stereo- and regiochemically heterogeneous polymers, the 1-cyclobutenecarboxylic acid esters and tertiary amides undergo ring-opening metathesis (ROM) but not ROMP. The regio- and stereochemical outcomes of these ROMP and ROM reactions were analyzed at the B3LYP/6-31G* and LANL2DZ levels of theory. Calculations suggest that the regiochemistry and stereochemistry of the addition to the propagating carbene to form the metallocyclobutane intermediate depend on both charge distribution and steric interactions.
Synthesis and chemical transformations of 2-cyclopropyl-2-diazoacetates
Prokopenko,Okonnishnikova,Klimenko,Shulishov,Tomilov
, p. 1515 - 1521 (2008/09/18)
Methyl 2-cyclopropyl-2-diazoacetate was synthesized from acetylcyclopropane in few chemical steps in ～55% total yield. Its copper or rhodium-catalyzed dediazoniation exclusively proceeds through the intramolecular isomerization of generated cyclopropyl(methoxycarbonyl)carbene to 1-methoxycarbonylcyclobutene, irrespective of the presence or the absence of unsaturated compounds. However, in the presence of acrylates or strained cycloalkenes, this diazo ester is being slowly involved into the 1,3-dipolar cycloaddition, giving cyclopropyl- substituted pyrazolinecarboxylates, which in case of 1-pyrazolines easily lose nitrogen molecule to selectively afford 1-cyclopropylcyclopropanecarboxylate derivatives.
Resistance-modifying agents. 8. Inhibition of O6-alkylguanine-DNA alkyltransferase by O6-alkenyl-, O6-cycloalkenyl-, and O6-(2-oxoalkyl)guanines and potentiation of temozolomide cytotoxicity in vitro by O6-(1-cyclopentenylmethyl) guanine
Griffin,Arris,Bleasdale,Boyle,Calvert,Curtin,Dalby,Kanugula,Lembicz,Newell,Pegg,Golding
, p. 4071 - 4083 (2007/10/03)
A series of O6-allyl- and O6-(2-oxoalkyl)guanines were synthesized and evaluated, in comparison with the corresponding O6-alkylguanines; as potential inhibitors of the DNA-repair protein O6-alkylguanine-DNA alkyltransferase (AGT). Simple O6-alkyl- and O6-cycloalkylguanines were weak AGT inactivators compared with O6-allylguanine (IC50 = 8.5 ± 0.6 μM)with IC50 values ranging from 100 to 1000 μM. The introduction of substituents at C-2 of the allyl group of O6-allylguanine reduced activity compared with the parent compound, while analogous compounds in the O6-(2-oxoalkyl)guanine series exhibited very poor activity (150-1000 μM). O6-Cycloalkenylguanines proved to be excellent AGT inactivators, with 1-cyclobutenylmethylguanine (IC50 = 0.55 ± 0.02 μM) and 1-cyclopentenylmethylguanine(IC50 = 0.39 ± 0.04 μM) exhibiting potency approaching that of the benchmark AGT inhibitor O6-benzylguanine (IC50 = 0.18 ± 0.02 μM). 1-Cyclopentenylmethylguanine also inactivated AGT in intact HT29 human colorectal carcinoma cells (IC50 = 0.20 ± 0.07 μM) and potentiated the cytotoxicity of the monomethylating antitumor agent Temozolomide by approximately 3- and 10-fold, respectively, in the HT29 and Colo205 tumor cell lines. The observation that four mutant AGT enzymes resistant to O6-benzylguanine also proved strongly cross-resistant to 1-cyclopentenylmethylguanine indicates that the O6-substituent of each compound makes similar binding interactions within the active site of AGT.
Process for preparation of intermediates of carbocyclic nucleoside analogs
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, (2008/06/13)
A compound of the formula: STR1 wherein A is a purin-9-yl group, a heterocyclic isostere of a purin-9-yl group, a pyrimidin-1-yl group or a heterocyclic isostere of a pyrimidin-1-yl group; E is hydrogen, --CH2 OH or --OH; and G and D are indepe
REACTIONS DE CYCLOBUTENES ELECTROPHILES AVEC LES ENAMINES. FACTEURS DETERMINANT L'OBTENTION DE DERIVES BICYCLOHEXANIQUES
Franck-Neumann, M.,Miesch, M.,Barth, F.
, p. 417 - 428 (2007/10/02)
When reacted with different ketone enamines, in the presence of magnesium bromide, 1-methoxycarbonyl- and 1-cyano-cyclobutene lead to α-cyclobutyl ketones or to amino-bicyclo hexane adducts.These products are not formed competitively, bat apparently result from different reactions.The cyclobutene nitrile undergoes an exclusive cycloaddition reaction with morpholino enamines.All other reagent combinations lead solely to cyclobutyl ketones.Some reactions of the cycloadducts, among them the thermolysis, were investigated.
