10.1039/c2ob06849d
The research focuses on the synthesis and conformational analysis of oxy-substituted butenolide spiroacetals and spiro-N,O-acetals, which are complex organic compounds with potential applications in the synthesis of natural products. The study involves the oxidative spirocyclisation of 2-[(4-hydroxy or 4-sulfonamido)butyl]furans to form the spiroacetals. The experiments utilize techniques such as NMR spectroscopy to investigate the axial–equatorial preference of oxy-substituents, employing an acid-catalysed thermodynamic relay to assess configurational bias. Reactants include 2-(4-hydroxybutyl)furan derivatives, various oxy-substituents, and reagents like OsO4, NMO, and MCPBA for the oxidation steps. The analysis involves crystallographic data for certain compounds, indicated by CCDC references, and discussions on the potential origins of the observed preferences, such as stabilizing gauche effects and solvation influences. The research has implications for the synthesis of bis(acetylenic)enol ether spiroacetals, including AL-1 and related compounds, and provides insights into the conformational preferences that can guide the selection of starting materials and synthetic routes.
10.1002/adsc.201000455
The research aimed to develop a mild and efficient catalytic oxidation system for the transformation of alkenes into various functional molecules, such as epoxides, aldehydes, and 1,2-diols. The study utilized a ruthenium porphyrin complex, dichlororuthenium(IV) meso-tetrakis(2,6-dichlorophenyl)porphyrin [Ru(IV)(TDCPP)Cl2], as a catalyst and 2,6-dichloropyridine N-oxide (Cl2pyNO) as the oxidant. The innovative aspect of this research was the ability to control the reaction pathway and product distribution by adjusting the oxidant loading, which allowed for the selective formation of aldehydes, epoxides, or 1,2-diols in moderate to excellent yields. This approach represents an advancement in the field of alkene dihydroxylation, as it provides a single catalytic system capable of producing three different types of compounds through "one-pot" cascade reactions, overcoming the limitations of previous methods that relied on more toxic and expensive catalysts like OsO4.
10.1016/S0040-4039(00)93423-3
The research aimed to develop a mild and chemoselective method for the oxidation of sulfides to sulfones, a transformation that is challenging due to the scarcity of mild and selective procedures. The study concluded that osmium tetraoxide, when used as a catalyst in conjunction with the co-oxidant N-methylmorpholine-N-oxide (NMO), is highly efficient for this oxidation, requiring only one mole percent to achieve nearly quantitative yields of sulfones from a variety of sulfides. The process is tolerant of other functional groups and can even selectively oxidize sulfides in the presence of olefins.
10.1248/cpb.50.453
The study focuses on the synthesis and antitumor activity of novel pyrimidinyl pyrazole derivatives, which were identified as potential antiproliferative agents. These compounds were designed to increase antitumor activity while reducing side effects associated with muscle relaxation and decreased body temperature. The research involved the structural modification of a specific chemical scaffold, particularly the phenylpiperazine moiety, by introducing substituents on the phenyl ring and replacing the phenylpiperazinyl group with piperidinyl groups. The chemicals used in the study included various aniline derivatives, piperazines, and pyrazole derivatives, as well as reagents for synthetic procedures such as bis(2-chloroethyl)amine hydrochloride, p-toluenesulfonic acid, sodium borohydride, and osmium tetraoxide. These chemicals served the purpose of constructing and modifying the target pyrimidinyl pyrazole derivatives to evaluate their in vitro cytotoxic activity against human lung cancer cell lines and their in vivo antitumor activity in murine tumor models. The study aimed to optimize the structure-activity relationship of these derivatives to enhance their efficacy as antitumor agents without causing significant side effects.
10.1016/S0040-4020(01)96078-8
The research focuses on the enantioselective syntheses of D- and L-ribo- and arabino-C,S-phytosphingosines, which are biologically important compounds found in plant sphingolipids and human brain and kidney lipids. The purpose of the study was to develop practical syntheses of these homochiral compounds from (R)-2,3-O-isopropylidene glyceraldehyde, utilizing key steps such as (Z)-selective olefination, selective monobenzoylation, Mitsunobu-type introduction of nitrogen, and osmylation. The conclusions drawn from the research indicate that the method is efficient, using inexpensive reagents and simple conditions suitable for gram-scale synthesis, and it also allows for the preparation of N- and O-protected derivatives, which could be useful for incorporating these compounds into biologically active ceramide and cerebroside structures. Chemicals used in the process include (R)-2,3-O-isopropylidene glyceraldehyde, phosphorane, benzoyl chloride, triphenylphosphine, diethyl azodicarboxylate, phthalimide, N-methyl-morpholine-N-oxide, osmium tetroxide, and various other reagents for protection and deprotection steps, as well as for chromatographic separation and analysis.
10.1002/jlcr.2914
The study details the synthesis of 14C-acanthoic acid, a pimaradiene diterpene with potential anti-inflammatory properties, through a four-step degradation/reconstitution strategy. Initially, acanthoic acid is dihydroxylated with osmium tetroxide to form vicinal diol 2. This diol is then subjected to oxidative cleavage with sodium periodate to produce aldehyde 3, which serves as the substrate for radiolabeling. A 14C-methylene Wittig reagent (4) is prepared using triphenylphosphine and 14CH3I, and this reagent is reacted with aldehyde 3 to yield the final product, 14C-acanthoic acid. The synthesis is notable for its regioselectivity and the high specific activity of the resulting 14C-acanthoic acid (52.7 mCi/mmol), making it suitable for pharmacological studies.
10.1021/acs.orglett.0c03990
The study presents an asymmetric total synthesis of (+)-PD-116740, an angucyclinone with potent anticancer activity. The synthesis involved a convergent approach with naphthalene-1,5-diol as the starting material, which was converted into quinone derivatives and then reduced to hydroquinone. Selective protection and bromination steps led to the formation of coupling precursors. The D ring fragment was prepared from benzyl alcohol, with TBS protection, lithium/bromide exchange, and conversion to an alkyne. A Pd-catalyzed Suzuki-Miyama coupling reaction combined the A/B and D ring fragments. Asymmetric dihydroxylation using osmium tetroxide and a chiral ligand introduced chirality. The core trans-9,10-dihydrophenanthrene-9,10-diol unit was constructed via oxidative cyclization using Cu(OH)OTf·NMI2 as the oxidant, which also facilitated phenol oxidation. Finally, global deprotection yielded PD-116740.
10.1016/S0040-4039(00)70704-0
The study investigates the osmylation of 3-substituted cyclopentenes, focusing on the stereochemical outcomes and the factors influencing selectivity. The chemicals involved include nitrosulfone 1 and 2, which serve as substrates for the osmylation reactions. Osmium tetroxide (OsO4) is used as the oxidizing agent, while MesNO2H2O is employed as a co-oxidant. The study observes that smaller substituents like CHR2 favor syn addition, while bulkier substituents like CMeR2 lead to anti addition. The results are interpreted through the lens of the stereodivergent nature of the reactive envelope conformations of the cyclopentene rings. The study also highlights the potential for catalytic osmylations under anhydrous conditions, using MesNO2H2O to facilitate osmate oxidation/hydrolysis without the need for water as a co-solvent.
This product is a nationally controlled contraband, and the Lookchem platform doesn't provide relevant sales information.
O, 
T, 
C, 
T+, 
Xi, 
Xn, 
F
