Related Products of 18531-94-7, The reaction rate of a catalyzed reaction is faster than the reaction rate of the uncatalyzed reaction at the same temperature.18531-94-7, Name is (R)-[1,1′-Binaphthalene]-2,2′-diol, molecular formula is C20H14O2. In a Article£¬once mentioned of 18531-94-7
Synthesis of Enantiomerically Pure Thiocrown Ethers Derived from 1,1′-Binaphthalene-2,2′-diol
Synthetic methodology is given for the preparation of two different types of thiocrown ethrs from optically pure 1,1′-binaphthalene-2,2′-diol (10).The conceptually simplest approach starts from optically pure 10 itself, which is alkylated (4 equiv of K2CO3 in DMF at 110 deg C) with 2-chloroethanol followed by mesylation to provide 2,2′-bis(2-mesyloxy)ethoxy)-1,1′-binaphthyl (14).When allowed to react with ethane-1,2-dithiol, propane-1,3-dithiol, 1,4,7–trithiaheptane, 1,4,8,11-tetrathiaundecane, 2,2-dimethylpropane-1,3-dithiol, 2-(mercaptomethyl)-1-propene-3-thiol, and 1,2-benzenedithiol in the presence of Cs2CO3 in DMF at 60 deg C the corresponding thiocrown ethers 22-25, 28, 30, and 32 are formed in 30-54percent yields.Test reactions were carried out to establish that no racemization occurs during alkylation under these conditions.Reaction of optically pure 10 with tetrahydropyranyl (THP)-protected 3-chloropropanol under similar conditions for the preparation of 14 proceeded more sluggishly but cleanly.Removal of the THP protecting groups afforded 2,2′-bis(3-bromopropoxy)-1,1′-binaphthyl (20), which on reaction with propane-1,3-dithiol, 1,5,9-trithianonane, 2,2-dimethylpropane-1,3-dithiol, 2-(mercaptomethyl)-1-propene-3-thiol, and 1,2-bis(mercaptomethyl)benzene provided the respective thiocrown ethers 26, 27, 29, 31, and 33 in 24-68percent yields.Another class of thiocrown ethers was prepared from optically active 10, which converted via ortho-lithiation to 3,3′-bis(bromomethyl)-2,2′-dimethoxy-1,1′-binaphthyl (39) by means of methylation (K2CO3/CH3I)), ortho-lithiation followed by formylation (n-C4H9Li/N,N,N’,N’-tetramethylethylenediamine (TMEDA)/ether followed by DMF and H2O workup) followed by reduction (NaBH4) followed by bromination (PBr3 in C5H5N).Reaction (Cs2CO3 in DMF at 60 deg C) with 1,4,7-trithiaheptane, 1,4,8-trithiaoctane, 1,4,7,10-tetrathiadecane, 1,4,8,11-tetrathiaundecane, and 1,5,10,14-tetrathiatetradecane afforded the corresponding thiocrown ethers 40-44 in 40-75percent yields.Despite repeated attempts using a wide range of reagents, demethylation of the methoxy ether functionalities failed.Attempts to prepare the free phenol derivatives of the latter type of grown ethers by oxuidative coupling of two naphthol units failed.
The reactant in an enzyme-catalyzed reaction is called a substrate. Enzyme inhibitors cause a decrease in the reaction rate of an enzyme-catalyzed reaction.I hope my blog about 18531-94-7 is helpful to your research. Related Products of 18531-94-7
Reference£º
Metal catalyst and ligand design,
Ligand Template Strategies for Catalyst Encapsulation – NCBI