Tetrahydrofuranyl

The catalytic oxidative carbonylation of allene with PdCb and CuCh in MeOH affords methyl a-methoxymethacrylate (559)[499]. The intramolecular oxidative aminocarbonylation of the 6-aminoallene 560 affords the unsaturated J-amino ester 561. The reaction has been applied to the enantioselective synthesis of pumiliotoxin (562)[500]. A similar intramolecular oxycarbonyla-tion of 6-hydroxyallenes affords 2-(2-tetrahydrofuranyl)acrylates[501]. 

It was thought that the acetal might have reacted with peroxy reagents, forming explosive peroxides. It was suggested that this could also occur with compounds such as tetrahydrofuranyl acetals, 1,3-dioxolanes, and methoxymethyl ethers. 

Ph2CHC02-2-tetrahydrofuranyl, 1% TsOH, CCI4, 20°, 30 min, 90-99% yield. The authors report that formation of the THF ether by reaction with 2-chlorotetrahydrofuran avoids a laborious proce ure that is required when dihydrofuran is used. In addition, the use of dihydrofuran to protect the 2 -OH of a nucleotide gives low yields (24-42%)." The tetrahydrofuranyl ester is reported to be a readily available, stable solid. A tetrahydrofuranyl ether can be cleaved in the presence of a THP ether. ... 

Fluorenylmethyl, 387 Methoxymethyl, 388 Methylthiomethyl, 389 Tetrahydropyranyl, 390 Tetrahydrofuranyl, 390 Methoxyethoxymethyl, 390 2-(Trimethylsilyl)ethoxymethyl, 391 Benzyloxymethyl, 391 Pivaloyloxymethyl, 391 Phenylacetoxymethyl, 392 Triisopropylsilylmethyl, 392 Cyanomethyl, 392 Acetol, 393 Phenacyl, 393... 

Tetrahydrofuranyl Ester RC02-2-tetrahydrofuranyl Formation/Cleavage ... 

Aminophenol was being oxidised in THF solution at 65°C using a larger than normal proportion of potassium dioxide. When stirring was stopped after 6 h, a violent explosion occurred. This was attributed to formation of tetrahydrofuranyl hydroperoxide by the excess dioxide. THF was described as an unsafe solvent for superoxide reactions [1], A later attempt at the same reaction in toluene also led to explosion, now blamed on the substrate [2],... 

Colon adenocarcinoma epithelial cell line Rat renal proximal tubular epithelial cell line Tetrahydrofuranyl Valacyclovir hydrolase... 

Bitha, P., Lin, Y. I., Testa, T., In vivo activities of peptide prodrugs of novel aminomethyl tetrahydrofuranyl-1 beta-methylcarbapenems, Antimicrob. 

The tetrahydrofuranylation of alcohols with hypervalent iodine compounds is described in [479]. 

The structures of sclerophytins A 17 and B 18, isolated from the soft coral Sclerophytum capitalis, were revised on basis of spectroscopic re-evaluation . Two unusual flavonoid tetrahydrofuranyl skeletons, namely tephrorin A 19 and B 20, were identified from Tephrosia purpurea . An alkaloid cartormin 21 was isolated and identified from Carthamus tinctorius, a plant used widely as a traditional Chinese medicine, <00TL1955>. 

The oxepane and oxepanone derivatives 51 and 52 respectively, were made by allylindation of, or allylmagnesium bromide addition to, acyclic tetrakis(tetrahydrofuranyl) dialdehydes. The solid state conformation of 52 was determined by X-ray diffraction analysis <00JOC4303>. 

Compared to the well-known OBO esters [81], the ABO esters are more stable towards protic acids but less stable towards the Lewis acid Cp2ZrCl2/AgC104, which isomerizes the ABO orthoester to a tetrahydrofuranyl ester. Selective deprotection is therefore possible (Scheme 8.41). 

Although alcohols are oxidized by tetra-n-butylammonium persulphate when the reaction is conducted in dichloromethane, tetrahydropyranyl ethers have been produced (>90%) when attempts to oxidize the alcohol are conducted in tetrahydro-pyran (see Chapter 10) [ 19], Tetrahydrofuranyl ethers have been prepared by an analogous method [20,21 ]. Base-mediated elimination of halo acids from P-halo alcohols under phase-transfer catalysed conditions produce oxiranes in high yield (70-85%). The reaction has particular use in the synthesis of epihalohydrins from p,y-dihalo alcohols [22],... 

The alcohol (l mmol) and (TBA)2-S20, (0.98 g, 1.4 mmol) in THF or THP (10 ml) are stirred under reflux for 3 h. The solvent is evaporated under reduced pressure and H20 (25 ml) is added to the residue, which is then extracted with Et20 (2 x 15 ml). The extracts are dried (MgS04) and evaporated to yield the tetrahydrofuranyl or tetrahydropyranyl ether. 

J. B. Jones, R. S. Hinks, P. G. Hultin, Enzymes in Organic Synthesis. 33. Stereoselective Pig Liver Esterase-Catalyzed Hydrolyses of meso Cyclopentyl-, Tetrahydrofuranyl-, and Tetrahydrothiophenyl-1,3-Diesters , Can. J. Chem. 1985, 63, 452-456. 

Sulfur analogs, 2-tetrahydrofuranyl and 2-tetrahydropyranyl thioethers, were reduced by alone to alkyl 4- or alkyl 5-hydroxyalkyl thioethers resulting from the preferential reductive cleavage of the carbon-oxygen (rather than the carbon-sulfur) bond. Thus refluxing for 2 hours with alane in ether converted 2-alkylthiotetrahydrofurans to alkyl 4-hydroxybutyl thioethers in 63-72% yields, and 2-alkylthiotetrahydropyrans to alkyl 5-hydroxypentyl thioethers in 58-82% yields [794]. 

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