نتایج جستجو برای: 2 substituted diols
تعداد نتایج: 2551101 فیلتر نتایج به سال:
Synthesis, Characterization and in Vitro Evaluation of New Composite Bisphosphonate Delivery Systems
In this study, new composite bisphosphonate delivery systems were obtained from polyurethanes (PUs) and nanocrystalline hydroxyapatite (HA). The biodegradable PUs were first synthesized from poly(ε-caprolactone) diols (PCL diols), poly(ethylene adipate) diol, 1,6-hexamethylene diisocyanate, 1,4-butanediol and HA. Moreover, the PCL diols were synthesized by the ring-opening polymerization cataly...
A new method for the ring expansion of cyclic diols is described. Using improved conditions for the ruthenium(0) catalyzed cycloaddition of cyclic 1,2-diols with 1,3-dienes, fused [n.4.0] bicycles (n = 3-6) are formed, which upon exposure to iodosobenzene diacetate engage in oxidative cleavage to form the 9-12 membered rings .
A new ruthenium complex catalyzes the amination of primary and secondary alcohols and the regioselective mono- and sequential diamination of diols via the borrowing hydrogen pathway. Several variations on new intra- and intermolecular cyclizations of aminoalcohols, diols and diamines lead to heterocyclic ring systems.
Long-chain 1,2-diols constitute the hydrophobic backbone of membrane lipids (replacing glycerolipids) in the thermophilic eubacterium Thermomicrobium roseum. The effects of incubation temperature on chain length and chain branching of diols and fatty acids were investigated. The percentage of branched chains decreased, and chain length increased slightly, with increased growth temperatures.
A catalytic amount of TEMPO in the presence of PhI(OAc)(2) effected oxidative lactonization of 1,6- and 1,7-diols, directly affording seven- and eight-membered lactones, respectively, in good yields.
reaction of substituted-aniline (8) with ethyl (l-methyl-5-nitroimidazole-2- carbonyl) acetate (9) gave 4-hydroxy-2-(l-methyl-5-nitro-2-imidazolyl)- substituted-quinolines (lo), which were converted to compound 11 with phosphorus oxychloride. substituted-2-(l-methyl-5-nitro-2-imidazo1yl)-4.- methyl-(or phenyl-) quinolines (14) were prepared through the reaction of 2- acetyl-5-nitro-1-methyl-imi...
1,4-Disubstituted 2,3-dioxabicyclo[2.2.2]oct-5-enes were dihydroxylated with osmium tetroxide to yield diols anti to the peroxide linkage in a highly selective manner. Reduction of the peroxide bond furnished cyclohexane-1,2,3,4-tetraols with toxocarol relative stereochemistry in excellent yield. This new methodology was employed to synthesize the natural product (1S,2R,3S,4R,5R)-2-methyl-5-(pr...
In association with increasing diabetes prevalence, it is desirable to develop new glucose sensing systems with low cost, ease of use, high stability and good portability. Boronic acid is one of the potential candidates for a future alternative to enzyme-based glucose sensors. Boronic acid derivatives have been widely used for the sugar recognition motif, because boronic acids bind adjacent dio...
reaction of readily available 2-formyl -1-methyl-5-nitroimidazole (1) with 4-substituted-2-hydrazinothiazoles (2) afforded 2-formyl-l-methyl-5- nitroimidazole 4-substituted -2- thiazolylhydrazones (3). reaction of thiochromitn-4-one (4) with thiosemicarbazide gave thiochroman-4- one thiosemicarbazone (5). reaction of compound 5 with clc- haloaldehyde or ketones y ielded thiochroman--#-one 4-sub...
New types of asymmetric functionalizations of alkenes are highly desirable for chemical synthesis. Here, we develop three novel types of regio- and enantioselective multiple oxy- and amino-functionalizations of terminal alkenes via cascade biocatalysis to produce chiral α-hydroxy acids, 1,2-amino alcohols and α-amino acids, respectively. Basic enzyme modules 1-4 are developed to convert alkenes...
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