- Hydroboration-oxidation of (±)-(1α,3α,3aβ,6aβ) -1,2,3,3a,4,6a-hexahydro-1,3-pentalenedimethanol and its O-protected derivatives: Synthesis of new compounds useful for obtaining (iso)carbacyclin analogues and X-ray analysis of the products
-
Hydroboration-oxidation of 2α,4α-dimethanol-1β,5β-bicyclo[3.3.0]oct-6-en dibenzoate (1) gave alcohols 2 (symmetric) and 3 (unsymmetric) in ~60% yield, together with the monobenzoate diol 4a (37%), resulting from the reduction of the closer benzoate by the
- T?nase, Constantin I.,Cocu, Florea G.,C?proiu, Miron Teodor,Dr?ghici, Constantin,Shova, Sergiu
-
-
Read Online
- Methods for the Synthesis of Piperazine Derivatives Containing a Chiral Bi-2-naphthyl Moiety
-
Piperazine derivatives containing 1,1′-bi-2-naphthyl moiety were synthesized starting from 2,2′-dimethoxy-1,1′-bi-naphthalene via acylation using ethyl chlorooxoacetate and subsequent condensation with 1,2-diamines followed by reduction of the corresponding dihydro-2-piperazinone intermediate using the NaBH 4 /I 2 reagent system. The corresponding chiral piperazine derivatives containing bi-2-napthyl moiety was synthesized by asymmetric reduction of ethyl dimethoxy-bi-2-naphthyloxoacetate by chiral oxazoborolidine catalyst prepared in situ using S -diphenylprolinol (S -DPP), B(OCH 3) 3 and H 3 B·THF. The resulting diols were mesylated and cyclized using 1,2-diamines to obtain the corresponding chiral piperazine derivatives.
- Mohan, Lakavathu,Nagaraju, Miriyala,Periasamy, Mariappan,Venkanna, Boda
-
-
Read Online
- Unravelling a general mechanism of converting ionic B/N complexes into neutral B/N analogues of alkanes: H: δ +?Hδ - ydrogen bonding assisted dehydrogenation
-
Long-sought mechanisms for the conversion of diammoniate of diborane ([NH3BH2NH3]+[BH4]-) into NH3BH3 and [NH2BH2]n as well as ammonium aminodiborane ([NH4]+[BH3NH2BH3]-) into a butane analogue, NH3BH2NH2BH3, have been elucidated on the basis of extensive experimental and theoretical studies. The [NH4]+ ammonium cation and the (η2-H2)BH2R moiety are found to be critical in B/N chain expansion.
- Chen, Xi-Meng,Liu, Si-Cong,Xu, Cong-Qiao,Jing, Yi,Wei, Donghui,Li, Jun,Chen, Xuenian
-
-
Read Online
- Mechanisms of the Reactions of B-Substituted Amine Boranes with THF·BH3
-
The reactions of NH3BH2R (R = Me, Ph and Cl) with THFBH3 have been investigated and it was found that different substituents on the B atom help to proceed the reactions in different ways. The expected doubly-bridged B-substituted aminodiborane products, similar to aminodiborane (ADB, BH2(μ-H)(μ-NH2)BH2) via the reaction of ammonia borane (AB, NH3BH3) and tetrahydrofuran borane (THFBH3), are not obtained. Two competitive reactions occurred with the change of R = Me or Ph. When R is a Me group, an “open“ version of B-substituted μ-aminodiborane, THFBH(Me)(μ-NH2)BH3, is formed as a major product; when R is a Ph group, AB and THFBH2Ph are formed as main products via the intermolecular NH3–THF exchange reaction. However, if R is Cl, then NH3BH2Cl reacts with THFBH3 through reversible intermolecular Cl–H exchange mechanism. Furthermore, DFT calculations are performed to elucidate the formation mechanism of THFBH(Me)(μ-NH2)BH3 via the reaction of NH3BH2Me and THFBH3 as well as the exchange mechanism of Cl–H in the reaction of NH3BH2Cl and THFBH3.
- Guo, Yu,Wang, Xinghua,Ma, Nana,Cao, Yilin,Hussain, Sajjad,Zhang, Jie,Wei, Donghui,Chen, Xuenian
-
p. 4994 - 4999
(2019/12/24)
-
- The pentafluoroethyltrihydridoborate anion: From shock sensitive salts to stable room temperature ionic liquids
-
The reaction of pentafluoroethyllithium with BH3·thf yields [C2F5BH3]- that is stable against H2O, OH- and air due to the electron withdrawing C2F5 group. M[C2F5BH3] (M = K, Cs) are shock sensitive solids whereas salts with organic cations such as the room temperature ionic liquid [EMIm][C2F5BH3] are stable for years. [C2F5BH3]- is a mild reducing agent, which is also reflected by its electrochemical properties. Oxidation with I2 or Br2 in the presence of Lewis bases yields the first stable adducts C2F5BH2·L.
- Hennig,Sprenger,Schneider,Ignat'Ev,Finze
-
supporting information
p. 6110 - 6113
(2019/06/03)
-
- Stabilizer-containing borane reagent combination solution, and preparation method and use thereof
-
The invention provides a stabilizer-containing borane reagent combination solution. The borane reagent combination solution comprises a borane-dimethyl sulfide complex, tetrahydrofuran and a stabilizer, wherein the concentration of the borane-dimethyl sulfide complex in tetrahydrofuran is 1-10 mol/L, and a molar ratio of the borane-dimethyl sulfide complex to the stabilizer is 100:1 to 1000:1. Thecombination solution has the advantages of high concentration, good thermal stability, realization of high-efficiency utilization of a reaction container, and saving of the tetrahydrofuran reagent toreduce the cost; and the combination solution achieves a good reaction enantioselectivity and a high enantiomeric excess value (% ee) of a product when applied to Corey asymmetric reduction.
- -
-
Paragraph 0037-0038
(2018/06/04)
-
- Understanding hydrogen sulfide storage: Probing conditions for sulfide release from hydrodisulfides
-
Hydrogen sulfide (H2S) is an important biological signaling agent that exerts action on numerous (patho)physiological processes. Once generated, H2S can be oxidized to generate reductant-labile sulfane sulfur pools, which include hydrodisulfides/persulfides. Despite the importance of hydrodisulfides in H2S storage and signaling, little is known about the physical properties or chemical reactivity of these compounds. We report here the synthesis, isolation, and characterization (NMR, IR, Raman, HRMS, X-ray) of a small-molecule hydrodisulfide and highlight its reactivity with reductants, nucleophiles, electrophiles, acids, and bases. Our experimental results establish that hydrodisulfides release H2S upon reduction and that deprotonation results in disproportionation to the parent thiol and S0, thus providing a mechanism for transsulfuration in the sulfane sulfur pool.
- Bailey, T. Spencer,Zakharov, Lev N.,Pluth, Michael D.
-
supporting information
p. 10573 - 10576
(2014/08/18)
-
- NOVEL INDOLE DERIVATES AS FABP-4 INHIBITORS
-
The present invention relates to novel compounds (I) wherein R0, R1, R2, R3, R4, R5, R6, R7, R8, A, B, n, X, and Y are as defined in the description and claims; and also to pharmaceutical compositions comprising the compounds, as well as to the use of the compounds in medicine and for the preparation of a medicament, which acts on the fatty acid binding protein FABP-4. The present invention relates to novel compounds (I) wherein R0, R1, R2, R3, R4, R5, R6, R7, R8, A, B, n, X, and Y are as defined in the description and claims; and also to pharmaceutical compositions comprising the compounds, as well as to the use of the compounds in medicine and for the preparation of a medicament, which acts on the fatty acid binding protein FABP-4.
- -
-
-
- Organoboranes. 49. An examination of convenient procedures for the generation of borane and monoalkyl- and dialkylboranes from lithium borohydride and monoalkyl- and dialkylborohydrides
-
The simple preparation of monoalkyl- and dialkylboranes previously developed by the addition of methyl iodide to lithium monoalkyl- and dialkylborohydrides in tetrahydrofuran solution has been expanded to alternative procedures involving other solvents, such as diethyl ether (EE) and n-pentane, and other reagents, such as phenol, acetic acid, methanesulfonic acid, ethereal hydrogen chloride, trimethylsilyl chloride, and trimethylsilyl methanesulfonate. The practicality of generating monoalkyl- and dialkylboranes from the corresponding borohydrides has been demonstrated in representative solvents utilizing appropriate reagents. The reaction of lithium borohydride with the above reagents was also studied. The reaction of lithium borohydride with 1 equiv of acetic acid produces a mixture of lithium tetraacetoxyborohydride and unreacted lithium borohydride instead of the expected lithium monoacetoxyborohydride. Because of discrepancies with the reported results for sodium borohydride, the study was extended to this reagent.
- Cole, Thomas E.,Bakshi, Raman K.,Srebnik, Morris,Singaram, Bakthan,Brown, Herbert C.
-
p. 2303 - 2307
(2008/10/08)
-
- Reaction of tetraborane(10) with trimethylphosphine in tetrahydrofuran
-
When tetraborane(10) was treated with trimethylphosphine in a 1:1 molar ratio in tetrahydrofuran at -90 to -70°C, (CH3)3P·BH3, THF·B3H7, and H2B(THF)2+B3H8 - were produced. The formation of (CH3)3P·B3H7 was minimal. The same reaction was performed in dimethyl ether, diethyl ether, and dichloromethane, and the patterns of product distribution were compared with each other. The previously proposed mechanism for the B4H10 cleavage reactions was used to explain the observed results by taking the effects of concentrations and strength of the reacting bases into consideration. This mechanistic model explained also the results of the reactions of B4H10 with trimethylamine and phosphine in tetrahydrofuran. The values of 4 ± 1 and 0.41 ± 0.02 were obtained as the equilibrium constants for (CH3)3P·BH3 + THF·B3H7 ? THF·BH3 + (CH3)3P·B3H7 at 25°C and H3P·BH3 + THF·B3H7 ? THF·BH3 + H3P·B3H7 at 0°C, respectively.
- Shimoi, Mamoru,Kodama, Goji
-
p. 3300 - 3304
(2008/10/08)
-
