18403-22-0Relevant academic research and scientific papers
Hafnium trifluoromethanesulfonate catalyzed silyl ether protecting group removing method
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Paragraph 0009; 0013; 0014, (2019/01/21)
The invention provides a hafnium trifluoromethanesulfonate catalyzed silyl ether protecting group removing method. Various silyl ether protecting groups of nearly 50 kinds of substrates can be efficiently removed in 0.5-16 hours at room temperature by taking 0.02mol%-0.3mol% hafnium trifluoromethanesulfonate as a catalyst, a silyl ether protected hydroxyl compound as a substrate and conventional AR methanol as a solvent. 42 kinds of silyl ether protecting group removing products can be obtained at high yield by performing conventional slica column chromatography purification on a crude product. By regulating the use amount of the catalyst, the Hf(OTf)4 catalyst can realize regioselective removal of 1-degree, 2-degree and 3-degree alkyl TBS and aryl TBS protective groups. Moreover, in a proper equivalent scope, the Hf(OTf)4 catalyst can also realize 1) chemoselective removal of different kinds of silica-based protective groups; and 2) chemoselective removal of 1-degree TBS protective groups under the condition of not affecting a majority of common hydroxyl protective groups.
BIARYL AMIDES WITH MODIFIED SUGAR GROUPS FOR TREATMENT OF DISEASES ASSOCIATED WITH HEAT SHOCK PROTEIN PATHWAY
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Page/Page column 145; 180; 183, (2019/12/04)
Provided are biaryl amides and coumarin-based compounds with modified sugar groups for treatment of diseases associated with heat shock protein pathway. The compounds having the following formulas, wherein variables are as defined herein. Formulae (I), (II), (III), (IV), and (V), Pharmaceutical compositions of the compounds are also provided. These biaryl amides and coumarin-based derivatives with modified sugar groups are useful for treatment and prevention of diseases and disorders, including neurological disorders, such as neurodegenerative diseases and nerve damaging disorders, for example, diabetic peripheral neuropathy.
Hafnium Triflate as a Highly Potent Catalyst for Regio- and Chemoselective Deprotection of Silyl Ethers
Zheng, Xiu-An,Kong, Rui,Huang, Hua-Shan,Wei, Jing-Ying,Chen, Ji-Zong,Gong, Shan-Shan,Sun, Qi
, p. 944 - 953 (2019/02/10)
As a Group IVB transition metal Lewis acid, hafnium triflate [Hf(OTf) 4 ] exhibited exceptionally high potency in desilylations. Since the amounts of Hf(OTf) 4 required for the deprotection of 1°, 2°, 3° alkyl and aryl tert -butyldimethylsilyl (TBS) ethers are significantly different, ranging from 0.05 mol% to 3 mol%, regioselective deprotection of TBS could be easily implemented. Moreover, chemoselective cleavage of different silyl ethers or removal of TBS in the presence of most hydroxyl protecting groups was also accomplished. NMR analyses of silyl products from TBS deprotection indicated that Hf(OTf) 4 -catalyzed desilylation may proceed via different mechanisms, depending on the solvent used.
Nucleoside analogues with a 1,3-diene-Fe(CO)3 substructure: Stereoselective synthesis, configurational assignment, and apoptosis-inducing activity
Hirschh?user, Christoph,Velcicky, Juraj,Schlawe, Daniel,Hessler, Erik,Majdalani, André,Neud?rfl, J?rg-Martin,Prokop, Aram,Wieder, Thomas,Schmalz, Hans-Günther
supporting information, p. 13017 - 13029 (2013/10/01)
The synthesis and stereochemical assignment of two classes of iron-containing nucleoside analogues, both of which contain a butadiene-Fe(CO)3 substructure, is described. The first type of compounds are Fe(CO)3-complexed 3'-alkenyl-2′,3′-dideoxy- 2′,3′-dehydro nucleosides (2,5-dihydrofuran derivatives), from which the second class of compounds is derived by formal replacement of the ring oxygen atom by a CH2 group (carbocyclic nucleoside analogues). These compounds were prepared in a stereoselective manner through the metal-assisted introduction of the nucleobase. Whilst the furanoid intermediates were prepared from carbohydrates (such as methyl-glucopyranoside), the carbocyclic compounds were obtained by using an intramolecular Pauson-Khand reaction. Stereochemical assignments based on NMR and CD spectroscopy were confirmed by X-ray structural analysis. Biological investigations revealed that several of the complexes exhibited pronounced apoptosis-inducing properties (through an unusual caspase 3-independent but ROS-dependent pathway). Furthermore, some structure-activity relationships were identified, also as a precondition for the design and synthesis of fluorescent and biotin-labeled conjugates. I gotta Fe-ling: Iron-containing nucleoside analogues, which were first synthesized during an exercise in stereoselective π-complex chemistry, exhibited pronounced cytotoxic and apoptosis-inducing activities, even against resistant cancer cell lines. Both hetero- (X=O) and carbocyclic (X=CH2) compounds were studied, and a synthetic route to R′-labeled derivatives was developed as a precondition for future biological experiments. TDS=thexyldimethylsilyl. Copyright
Regioselective ring opening of exo- and endo-3,4-benzylidene acetals of arabinopyranoside derivatives with Lewis acids and reducing agents
Rujirawanich, Janjira,Kongkathip, Boonsong,Kongkathip, Ngampong
experimental part, p. 927 - 932 (2011/06/20)
Dioxolane type 3,4-benzylidene acetals of benzyl β-l-arabinose either as a mixture or pure exo- and endo-isomers cleavaged with BF3· OEt2/Et3SiH in dichloromethane or acetonitrile regioselectively, provided the 4-O-benzyl-
Synthesis of 6- and 7-(1,2,3-trihydroxy-1,2-O-isopropyl-denepropyl)pteridines and deoxygenation of their 3′-hydroxy groups
Hanaya, Tadashi,Takayama, Daisuke,Yamamoto, Hiroshi
, p. 355 - 365 (2007/10/03)
Treatment of 3,4-O-isopropylidene-L-threo-pentos-2-ulose (7) with 5,6-diamino-1,3-dimethyluracil (8) afforded 1,3-dimethyl-6-[(1R,2S)-1,2,3-trihydroxy-1,2-O-isopropylidenepropyl]lumazine (9a) and its 7-substituted isomer (9b). Deoxygenation of 3′-hydroxy
Synthesis of two bidesmosidic ursolic acid saponins bearing a 2,3-branched trisaccharide residue
Wang, Peng,Li, Chunxia,Zang, Jing,Song, Ni,Zhang, Xiuli,Li, Yingxia
, p. 2086 - 2096 (2007/10/03)
The focus of this work was on the synthesis of two bidesmosidic ursolic acid saponins bearing a 2,3-branched trisaccharide residue. Therefore, 3-O-{[β-d-glucopyranosyl-(1→2)]-[α-l-arabinopyranosyl-(1→3) ]-α-l-arabinopyranosyl}ursolic acid-28-O-[β-d-glucop
A solid-phase approach to novel purine and nucleoside analogs
Chang, Junbiao,Dong, Chunhong,Guo, Xiaohe,Hu, Weidong,Cheng, Senxiang,Wang, Qiang,Chen, Rongfeng
, p. 4760 - 4766 (2007/10/03)
This paper describes a method for the preparation of purine analogs using the solid-phase approach. Nucleoside bases were constructed on Merrifield resin by sequential displacement of purine dichloride with amines, and after detachment, the purine analogs were condensed with d,l-ribofuranoside compounds by the Vorbrueggen method. Thereof, l-ribofuranoside was prepared from l-arabinose via the selective oxidation-reduction procedure of the 2-OH group. Some compounds exhibited moderate activity against HIV-1 in PBM cells.
2'-deoxy-L-nucleosides
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Page/Page column 42, (2010/02/11)
This invention provides processes for the preparation of compounds having the structure: wherein X and Y are same or different, and H, OH, OR, SH, SR, NH2, NHR′, or NR′R″Z is H, F, Cl, Br, I, CN, or NH2. R is hydrogen, halogen, lower alkyl of C1-C6 or aralkyl, NO2, NH2, NHR′, NR′R″, OH, OR, SH, SR, CN, CONH2, CSNH2, CO2H, CO2R′, CH2CO2H, CH2CO2R′, CH═CHR, CH2CH═CHR, or C═CR. R′ and R″ are same or different, and lower alkyl of C1-C6. R13 is hydrogen, alkyl, acyl, phosphate (monophosphate, diphosphate, triphosphate, or stabilized phosphate) or silyl; and
Enantiospecific synthesis of both enantiomers of 2-benzyloxydihydropyran-3- ones from arabinose
Uhrig, Maria Laura,Varela, Oscar
, p. 893 - 898 (2007/10/03)
Approaches to the enantioselective synthesis of the useful building blocks (2R)- and (2S)-2-benzyloxy-2(H)-pyran-3(6H)-one (12 and 17, respectively) are described. The most direct and highly yielding route for the synthesis of 12 was based on the 'one-pot
