- Ring-Closure Reactions. 22. Kinetics of Cyclization of Diethyl (ο-Bromoalkyl)malonates in the Range of 4- to 21-Membered Rings. Role of Ring Strain
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The kinetics of closure of 1,1-bis(ethoxycarbonyl)cycloalkanes from the anions derived from diethyl (ο-bromoalkyl)malonates have been investigated in Me2SO at 25 degC.Rate constants and effective molarities (EM) have been obtained for the ring sizes 4-13, 17, and 21.This is the first quantitative study on the kinetics of SN2 closure of all-carbon rings, which includes small, common, medium and large rings.The reactivity data span over nine powers of ten, which is the widest reactivity range recorded so far in a cyclization series.Due to the extremely low EM for the 9-, 10-, and 11-membered rings, a special competition technique was developed for these rings.Comparison of the present results with literaturee data on SN2 ring-closure reactions reveals structure-dependent reactivity patterns showing varying features, which are qualitatively accounted for on the basis of structure effects on transition-state strain energies.A dissection of the EM data for the malonate cyclization into strain and probability factors was attempted.Perhaps the most interesting result is a definite tendency for transition-state strain energies to parallel cycloalkane strain energies for the 7-membered and larger rings but not for the smaller rings.In the latter cases the ring product no longer appears to be a proper model for comprehending the transition state.
- Casadei, Maria Antonietta,Galli, Carlo,Mandolini, Luigi
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- GLYCOLATE OXIDASE INHIBITORS FOR THE TREATMENT OF DISEASE
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Described herein are compounds, methods of making such compounds, pharmaceutical compositions and medicaments containing such compounds, and methods of using such compounds to treat or prevent diseases or disorders associated with a defect in glyoxylate metabolism, for example a disease or disorder associated with the enzyme glycolate oxidase (GO) or alterations in oxalate metabolism. Such diseases or disorders include, for example, disorders of glyoxylate metabolism, including primary hyperoxaluria, that are associated with production of excessive amounts of oxalate.
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Paragraph 001498; 001499
(2021/01/22)
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- GLYCOLATE OXIDASE INHIBITORS FOR THE TREATMENT OF DISEASE
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Described herein are compounds, methods of making such compounds, pharmaceutical compositions and medicaments containing such compounds, and methods of using such compounds to treat or prevent diseases or disorders associated with the enzyme glycolate oxidase (GO). Such diseases or disorders include, for example, disorders of glyoxylate metabolism, including primary hyperoxaluria, that are associated with production of excessive amounts of oxalate.
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Paragraph 001540; 001541; 001542
(2019/07/17)
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- Diverse ring opening of thietanes and other cyclic sulfides: An electrophilic aryne activation approach
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Organosulfides are a common class of structure units in bioactive molecules and functional materials motivating continuous developments of efficient synthetic methods. Herein, we report an electrophilic aryne-activated ring opening protocol of one or two
- Zheng, Tianyu,Tan, Jiajing,Fan, Rong,Su, Shuaisong,Liu, Binbin,Tan, Chen,Xu, Kun
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supporting information
p. 1303 - 1306
(2018/02/14)
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- TRICYCLIC COMPOUND SERVING AS IMMUNOMODULATOR
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Provided are compounds of formula I and formula II or pharmaceutically acceptable salts of the compounds and pharmaceutical compositions thereof. The compounds of formula I and formula II or the pharmaceutically acceptable salts of the compounds provide indole 2,3-dioxygenase (IDO) inhibitory activity and are capable of treating IDO-mediated immunosuppressive diseases, such as infectious diseases or cancer.
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Paragraph 0449-0450
(2019/01/04)
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- In tandem or alone: A remarkably selective transfer hydrogenation of alkenes catalyzed by ruthenium olefin metathesis catalysts
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A system for transfer hydrogenation of alkenes, composed of a ruthenium metathesis catalyst and HCOOH, is presented. This operationally simple system can be formed directly after a metathesis reaction to effect hydrogenation of the metathesis product in a single-pot. These hydrogenation conditions are applicable to a wide range of alkenes and offer remarkable selectivity. This journal is
- Zieliski, Grzegorz Krzysztof,Samojlowicz, Cezary,Wdowik, Tomasz,Grela, Karol
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p. 2684 - 2688
(2015/04/14)
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- BENZISOXAZOLE COMPOUND
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Disclosed is a compound represented by the general formula (I) or a salt thereof: wherein any one of R1, R2 and R3 represents a group represented by the formula: -(CH2)m-NR11R12 (wherein m is 1 or 2; and R11 and R12 independently represent a hydrogen atom or a C1-6 alkyl group or may, together with a nitrogen atom to which R11 and R12 are bound, form a 4- or 5-membered cyclic group); the remaining two or R1, R2 and R3 independently represent a group represented by the formula: -(O)n-R21 (wherein n is 0 or 1; and R21 represents a hydrogen atom, a C1-6 alkyl group, a C2-6 alkenyl group, a C2-6 alkynyl group, or the like); and R4 represents a C1-6 alkyl group which may have a substituent or the like.
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Page/Page column 71
(2009/02/10)
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- Hydrazide-Based Quadruply Hydrogen-Bonded Heterodimers. Structure, Assembling Selectivity, and Supramolecular Substitution
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This paper describes the synthesis, self-assembly, and characterization of a new class of highly stable hydrazide-based quadruply hydrogen-bonded heterodimers. All of the hydrazide-derived heterodimers possess the complementary ADDA-DAAD hydrogen-bonding sequences. Hydrazide derivatives 1, which has two intramolecular S(6) RO...H-N hydrogen bonds, and 2 complex to afford two fastly exchanging isomeric heterodimers 1·2 and 1·2′ in chloroform, as a result of two different conformational arrangements of 2. An average binding constant Kassoc of 4.7 × 104 M-1 was determined for heterodimer 1·2 and 1·2′ by 1H NMR titration of 1 with changing 2 in chloroform-d. In contrast, 1 binds 11 and 12, both of which are introduced with two intramolecular S(6) hydrogen bonds, to exclusively afford heterodimers 1·11 and 1·12, with Kassoc values of 1.8 × 104 and 5.0 × 102 M-1, respectively. Fluorine-containing 19, which has a hydrazide skeleton identical to that of 1 but two intramolecular S(6) F...H-N hydrogen bonds, can also complex with 2, 11, and 12, to afford heterodimers 19·2, 19·2′, 19·11, and 19·12, with Kassoc values of of 1.2 × 104 (average value for 19·2 and 19·2′), 5.4 × 103, and 1.9 × 102 M-1, respectively. The structures of the new heterodimers have been proven with NOESY, IR, and VPO (for some of the heterodimers) experiments. Moreover, 1 and 19 can also strongly bind 2,7-dilauroylamido-1,8-naphthyridine 23 to afford dimers 1·23 and 19·23 with Kassoc values of 6.0 × 105 and 1.4 × 105 M-1, respectively. Adding 1 to the 1:1 solution of 23 and 1-octyl-3-(4-oxo-3,4-dihydro-pyrido[2,3-d]pyrimidin-2-yl)urea 24 or 1-octyl-3-(4-oxo-1,4-dihydropyrimidin-2-yl)urea 25, which had been developed initially by Zimmerman and Meijer, respectively, induces dimers 23·24 and 23·25 to dissociate, leading to the formation of dimers 1·23 and 24·24 or 25·25, respectively. The new hydrazide-based hydrogen-bonding modules described are useful building blocks for self-assembly and open a new avenue to recognition between discrete supramolecular species.
- Zhao, Xin,Wang, Xiao-Zhong,Jiang, Xi-Kui,Chen, Ying-Qi,Li, Zhan-Ting,Chen, Guang-Ju
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p. 15128 - 15139
(2007/10/03)
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- Selective reactions of 1,1-cycloalkanedicarboxylic acids with SF4. a route to 1,1-bis(trifluoromethyl)cycloalkanes, 1-fluoroformyl-1-(trifluoromethyl)cycloalkanes and 1-(trifluoromethyl)-1-cycloalkanecarboxylic acids
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Six-, five-, four- and three-membered 1,1-cycloalkanedicarboxylic acid (2a-d) were synthesized by alkaline hydrolysis of the corresponding diesters (1a-d) and the reactions of the formers with SF4 were investigated. 1,1-Bis(trifluoromethyl)cycloalkanes (3a-d) were the products of the reactions conducted at 120-150°C while at 30°C 1-fluoroformyl-1-(trifluoromethyl)cycloalkanes (4a-d) were exclusively formed. The latter were isolated as pure compounds or converted in situ into 1-(trifluoromethyl)-1-cycloalkanecarboxylic acids (5a-d).
- Dmowski, Wojciech,Wolniewicz, Adam
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p. 141 - 146
(2007/10/03)
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- Octacidomycins, IV : A new total synthesis of rac-octacidomydn and structurally related oligocarboxylic acids
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Following a new strategy, an improved total synthesis of the unique antibiotic octacidomycin (1) and of structurally related oligocarboxylic acids was developed (Scheme 1,2). Starting from 3 and the tetraethylester of 1,17-dibromo-6,6,12,12-heptadecane-te
- Krause, Andreas,Lackner, Helmut
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p. 1043 - 1050
(2007/10/03)
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- Laser-Powered Decomposition of Spiroalkanes (n = 2-5)
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The laser heating of spiroalkanes (n=2-5) and of their 1,1,2,2-tetradeuterated isotopomers reveals dissimilar modes of their thermal decomposition.Spiropentane decomposes into ethene and propadiene via two competing routes: the direct cleavage and the more important cleavage via intermediary methylenecyclobutane.Spirohexane decomposes through two important concurrent pathways which are the expulsions of ethene from the three-membered ring and a more feasible expulsion of ethene from the four-membered ring.Spiroheptane and spirooctane decompose by a radical-chain mechanism and afford complex mixtures of products; upon addition of propene both compounds rearrange into two cycloalkanes wherein the larger ring of the spiroalkane is preserved and substituted with ethylidene and a vinyl group.
- Fajgar, Radek,Pola, Josef
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p. 7709 - 7717
(2007/10/02)
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- Perkin-Markovnikov Type Reaction Initiated with Electrogenerated Superoxide Ion
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The cyclic condensation of α,ω-dihaloalkanes with acticvated methylene of malonic acid and acetoacetic acid esters is studied using an electrogenerated superoxide ion.Two possible mechanisms for this reaction are postulated.
- Ojima, Fumihiro,Matsue, Tomokazu,Osa, Tetsuo
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p. 2235 - 2238
(2007/10/02)
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- ION PAIRING AND REACTIVITY OF THE ALKALI-METAL DERIVATIVES OF DIETHYL 5-BROMOPENTYLMALONATE
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The effect of added tetraethylammonium and alkali-metal (Li,Na,K) bromides on the raet of cyclisation of the anion derived from diethyl 5-bromopentylmalonate has been studied over a wide concentration range in 99percent aqueous Me2SO at 25 deg C.Whereas t
- Galli, Carlo,Mandolini, Luigi
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p. 1435 - 1438
(2007/10/02)
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- Crown ether catalysis of decarboxylation and decarbalkoxylation of β-keto acids and malonates: a synthetic application
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The effect of 18-crown-6 ether on the decarboxylation rates of the sodium and potassium salts of 3-camphor carboxylic acid 1 and of 1-carbomethoxy-1-carboxycyclohexane 2 was studied.For 2 the K-18C6 salt reacted ca. 104 times faster than the parent acid.This remarkable difference in reactivity was used in developing a one-pot, two-step procedure for decarbalkoxylation of malonic esters.This procedure was then applied to a range of malonates, β-keto esters, and an α-cyano ester.The effect of 15C5, other cations, and good nucleophiles was also studied.
- Hunter, Duncan H.,Patel, Vijay,Perry, Richard A.
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p. 2271 - 2277
(2007/10/02)
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