5221-17-0Relevant articles and documents
Enantioselective synthesis of trans-fused bicyclo[5.3.0]decane systems via a tandem [4+3] cycloaddition-Nicholas reaction
Montana, Angel M.,Fernandez, David
, p. 6499 - 6502 (1999)
An enantioselective synthetic methodology to prepare trans-fused bicyclo[5.3.0]decane systems is presented. It is a very versatile methodology based on two key reactions: [4+3] cycloaddition reaction (to generate the seven-membered ring) and the Nicholas reaction (that facilitates the insertion of the five-membered ring). This methodology allows the easy preparation of a wide range of bioactive natural products containing the transfused bicyclo[5.3.0]decane system. The application of this methodology to the enantioselective synthetic approach to the pseudoguaiane carbon- skeleton is described.
Synthesis and Some Transformations of Cyclic Acetals of Propargyl Aldehyde
Lukicheva,Golovanov,Nachkebia, Ya. A.,Bekin,Raskildina,Zlotskii
, p. 330 - 333 (2018/03/26)
Dehydrobromination of 2-(1,2-dibromoethyl)-1,3-dioxocyclanes with sodium amide in liquid ammonia provided cyclic acetals of propargyl aldehyde. Reactions of the resulting compounds with nitrile oxides and diazomethane afforded the corresponding isoxazole and pyrazole derivatives.
Method for synthesizing bis(2-methyl-3-furyl) disulfide
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Paragraph 0057-0060; 0081-0088; 0115-0118; 0139-0142, (2017/07/19)
The invention relates to a method for synthesizing bis(2-methyl-3-furyl) disulfide. The method comprises the following steps: (1) enabling acrolein to react with bromine to obtain a product 1; (2) adding the product 1 into an absolute ethyl alcohol solution of sodium hydroxide to prepare propiolaldehyde diethyl acetal; (3) enabling ethyl ether and bromoethane to react with chloroethane in presence of magnesium, then adding mixed liquid of the propiolaldehyde diethyl acetal and the ethyl ether and subsequently adding mixed liquid of acetaldehyde and ethyl ether for carrying out a reaction, and hydrolyzing to prepare 4-hydroxy-2-pentyne propanal diethyl acetal; (4) adding the 4-hydroxy-2-pentyne propanal diethyl acetal into a water solution containing sulfuric acid, pentane and potassium thiocyanate to prepare a product 4; (5) adding the product 4 into a sodium hydroxide water solution to prepare the bis(2-methyl-3-furyl) disulfide. Compared with the existing synthesis method, the method provided by the invention is easy in control of reaction conditions, fewer in side reactions, easy in control of intermediate products and higher in yield of a target product, thus having wide application prospect.
Enantioselective diels-alder reactions with anomalous endo/exo selectivities using conformationally flexible chiral supramolecular catalysts
Hatano, Manabu,Mizuno, Tomokazu,Izumiseki, Atsuto,Usami, Ryota,Asai, Takafumi,Akakura, Matsujiro,Ishihara, Kazuaki
supporting information; experimental part, p. 12189 - 12192 (2012/02/01)
Swapped selectivities: The use of tailor-made catalysts results in anomalous endo/exo selectivities and high enantioselectivities in the Diels-Alder reactions of cyclopentadiene with different acroleins (see scheme). These supramolecular catalysts are prepared in situ from chiral diols, arylboronic acid, and tris(pentafluorophenyl)borane, and can discriminate the re/si face of the dienophile as well as the endo/exo approach of the diene.
Propynal equivalents and diazopropyne: Synthesis of all mono-13C isotopomers
Seburg, Randal A.,Hodges, Jonathan A.,McMahon, Robert J.
experimental part, p. 1626 - 1643 (2009/10/17)
Mechanistic and spectroscopic investigations of reactive C 3H2 hydrocarbons necessitated the preparation of diazopropyne isotopomers bearing mono-13C substitution at each of the three unique positions. The diazo compounds and their tosylhydrazone precursors were prepared from the mono-13C isotopomers of propynal (in the form of either the aldehyde or the diethyl acetal). The introduction of 13C-labeling at either alkyne position in propynal utilized the Corey - Fuchs procedure for chain homologation.
Efficient access to isoxazoles from alkenes
Xu, Jianping,Hamme II, Ashton T.
, p. 919 - 923 (2008/12/22)
The direct regioselective synthesis of 3,5-disubstituted isoxazoles was achieved in one reaction vessel through a sequence of reactions involving the net bromination of an electron-deficient alkene, in situ generation of a nitrile oxide, 1,3-dipolar cycloaddition, and loss of HBr from an intermediate 5,5-disubstituted bromoisoxazoline. This one-pot process enables the synthesis of 3,5-disubstituted isoxazoles directly from electron-deficient alkenes thereby negating the isolation of the 1,1-disubstituted bromoalkene alkyne surrogate. Georg Thieme Verlag Stuttgart.
An economical and convenient synthesis of vinyl sulfones
Guan, Zheng-Hui,Zuo, Wei,Zhao, Lian-Biao,Ren, Zhi-Hui,Liang, Yong-Min
, p. 1465 - 1470 (2008/02/05)
A general process for the efficient synthesis of vinyl sulfones has been developed using commercially available sulfinic acid sodium salts and dibromides. A variety of phenyl and methyl vinyl sulfones have been formed in good yields, in the absence of any catalyst. Georg Thieme Verlag Stuttgart.
Preparation of α-haloacrylate derivatives via dimethyl sulfoxide-mediated selective dehydrohalogenation
Li, Wei,Li, Jianchang,Wan, Zhao-Kui,Wu, Junjun,Massefski, Walter
, p. 4607 - 4610 (2008/03/13)
(Chemical Equation Presented) Dimethyl sulfoxide causes α/β-dihalopropanoate derivatives to undergo efficient, selective dehydrohalogenation to form α-haloacrylate analogues. A variety of α-halo Michael acceptors were prepared in dimethyl sulfoxide under mild, base-free conditions, including the preparation of α-bromoacrolein and α-chloro- and bromoacrylonitriles. Synthesis of these molecules has been reported in the literature to be difficult. Among all the existing dehydrohalogenation procedures, this protocol is the most facile, practical, and environmentally benign process.
Reactive carbon-chain molecules: Synthesis of 1-diazo-2,4-pentadiyne and spectroscopic characterization of triplet pentadiynylidene (H-C≡C-C- C≡C-H)
Bowling, Nathan P.,Halter, Robert J.,Hodges, Jonathan A.,Seburg, Randal A.,Thomas, Phillip S.,Simmons, Christopher S.,Stanton, John F.,McMahon, Robert J.
, p. 3291 - 3302 (2007/10/03)
1-Diazo-2,4-pentadiyne (6a), along with both monodeuterio isotopomers 6b and 6c, has been synthesized via a route that proceeds through diacetylene, 2,4-pentadiynal, and 2,4-pentadiynal tosylhydrazone. Photolysis of diazo compounds 6a-c (λ > 444 nm; Ar or N2, 10 K) generates triplet carbenes HC5H (1) and HC5D (1-d), which have been characterized by IR, EPR, and UV/vis spectroscopy. Although many resonance structures contribute to the resonance hybrid for this highly unsaturated carbon-chain molecule, experiment and theory reveal that the structure is best depicted in terms of the dominant resonance contributor of penta-1,4-diyn-3- ylidene (diethynylcarbene, H-C≡C-C-C≡C-H). Theory predicts an axially symmetric (D∞h) structure and a triplet electronic ground state for 1 (CCSD(T)/ANO). Experimental IR frequencies and isotope shifts are in good agreement with computed values. The triplet EPR spectrum of 1 (|D/hc| = 0.6157 cm-1, |E/hc| = 0.0006 cm-1) is consistent with an axially symmetric structure, and the Curie law behavior confirms that the triplet state is the ground state. The electronic absorption spectrum of 1 exhibits a weak transition near 400 nm with extensive vibronic coupling. Chemical trapping of triplet HC5H (1) in an O2-doped matrix affords the carbonyl oxide 16 derived exclusively from attack at the central carbon.
Claisen Orthoester Rearrangement in the Direct Preparation of Z-Isositsirikine and Z-Geissoschizine Derivatives Possessing the Right Oxidation State at C-17
Lounasmaa, Mauri,Hanhinen, Pirjo,Jokela, Reija
, p. 8623 - 8648 (2007/10/02)
The Claisen orthoester rearrangement utilizing allylic alcohol 1 (or 2) and trimethyl 3-methoxyorthopropionate 13a leads to Z-isositsirikine derivatives 21a-22a (or 23a-24a) possessing one RO-function at C-17.In the cases of trialkyl 3,3-dialkoxyorthopropionates , the intermediate ketene acetals 25a,b do not rearrange according to the Claisen mechanism to form compounds 26a,b and/or possessing two two RO-functions at C-17.Syntheses of the intermediate orthoesters, trimethyl 3-methoxyorthopropionate 13a, trimethyl 3,3-dimethoxyorthopropionate 14a, trimethyl trans-3-methoxyorthoacrylate 20c, and triethyl 3,3-diethoxyorthopropionate 14b are described.
