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Tetrahydropyranation

Diiodobutane and 1 5 diiodopentane are eonveniently obtained from tetrahydrofuran and tetrahydropyran respectively (compare corresponding bromides above). [Pg.272]

Some allenic alcohols can be prepared in analogous waysfrom acetylenic epoxides or tetrahydropyrans ... [Pg.152]

In MeOH, l,4-dimethoxy-2-cyclohexene (379) is obtainejl from 1,3-cydo-hexadiene[315]. Acetoxylation and the intramolecular alkoxylation took place in the synthesis of the naturally occurring tetrahydrofuran derivative 380 and is another example of the selective introduction of different nucleo-philes[316]. In intramolecular 1,4-oxyacetoxylation to form the fused tetrahy-drofurans and tetrahydropyrans 381, cis addition takes place in the presence of a catalytic amount of LiCI, whereas the trans product is obtained in its absence[317]. The stereocontrolled oxaspirocyclization proceeds to afford the Irons product 382 in the presence of Li2C03 and the cis product in the presence of LiCl[ 318,319]. [Pg.70]

Typical carbon-oxygen bond distances m ethers are similar to those of alcohols (—142 pm) and are shorter than carbon-carbon bond distances m alkanes (—153 pm) An ether oxygen affects the conformation of a molecule m much the same way that a CH2 unit does The most stable conformation of diethyl ether is the all staggered anti conformation Tetrahydropyran is most stable m the chair conformation—a fact that has an important bearing on the structures of many carbohydrates... [Pg.667]

In the NTC region, back-bitiag reactioas appear to be respoasible for the formation of cycHc ethers (60,165—170). la additioa to oxetanes and tetrahydrofurans, tetrahydropyrans, oxiranes, and others are also observed (60,96,169) the tetrahydrofurans are favored. 0-Heterocycle yields of 25 to 30% have been reported for / -pentane (165,171). Conjugate and other olefins are also prominent products ia this regioa (60,169—172). [Pg.342]

Alkoxyall l All l Peroxides. / /f-Butyl tetrahydropyran-2-yl peroxide [28627 6-5] (1), where R = tert — butyl, X = OR", R = H, R and R" = 1, 4 butanediyl, has been isolated. This is one of many examples of alkoxyalkyl alkyl peroxides which may be prepared by reaction of hydroperoxides with vinyl ethers (139) ... [Pg.114]

The ether oxygen of tetrahydropyran (45 X = O) induces a large downfield shift of the a carbons, while the /3 and y carbons move slightly upfield, the y more noticeably. [Pg.15]

Two interesting syntheses of the base followed in 1956 the first involves a Principal Synthesis from ethyl 2-cyano-2-(tetrahydropyran-2 -yloxy)acetate and guanidine to give the tetrahydropyranyloxypyrimrdine (949) which undergoes gentle acidic hydrolysis to... [Pg.143]

Methanol, l-isoquinolyl(phenyl)-confonnation, 2, 110 Methanol, pyrimidinyl-synthesis, 3, 113 Methanol, tetrahydropyran-2-yl-microwave spectra, 3, 625 Methantheline as neurotransmitter, 1, 175 therapeutic properties, 3, 882 Methaphenilene biological activity, 4, 911 Methapyrilene biological activity, 4, 911 toxicity, 4, 912 Methaqualone, 3, 150 as anticonvulsant, 1, 166 pyrido[2,3-d]pyrimidine analogues metabolism, 3, 205 as sedative, 1, 166 Metharbitone as anticonvulsant, 1, 166 Methazolamide... [Pg.702]

THF, Et3NHCe(ni) (N03)6, 50-100°, 8 h, 30-98% yield. Hindered alcohols give the lower yields. The method was also used to introduce the THP group with tetrahydropyran. [Pg.36]

Table 3.8. Comparison of Conformational Free-Energy Values for Substituents on Tetrahydropyran, 1,3-Dioxane, and 1,3-Dithiane Rings with Those for Cyclohexane... Table 3.8. Comparison of Conformational Free-Energy Values for Substituents on Tetrahydropyran, 1,3-Dioxane, and 1,3-Dithiane Rings with Those for Cyclohexane...
The incorporation of heteroatoms can result in stereoelectronic effects that have a pronounced effect on conformation and, ultimately, on reactivity. It is known from numerous examples in carbohydrate chemistry that pyranose sugars substituted with an electron-withdrawing group such as halogen or alkoxy at C-1 are often more stable when the substituent has an axial, rather than an equatorial, orientation. This tendency is not limited to carbohydrates but carries over to simpler ring systems such as 2-substituted tetrahydropyrans. The phenomenon is known as the anomeric ect, because it involves a substituent at the anomeric position in carbohydrate pyranose rings. Scheme 3.1 lists... [Pg.151]


See other pages where Tetrahydropyranation is mentioned: [Pg.280]    [Pg.283]    [Pg.284]    [Pg.284]    [Pg.317]    [Pg.461]    [Pg.462]    [Pg.486]    [Pg.525]    [Pg.608]    [Pg.608]    [Pg.687]    [Pg.776]    [Pg.158]    [Pg.166]    [Pg.424]    [Pg.144]    [Pg.517]    [Pg.591]    [Pg.694]    [Pg.700]    [Pg.738]    [Pg.762]    [Pg.766]    [Pg.766]    [Pg.767]    [Pg.3]    [Pg.484]    [Pg.361]    [Pg.239]    [Pg.150]    [Pg.150]   
See also in sourсe #XX -- [ Pg.355 ]




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2,6-disubstituted tetrahydropyrans

2- -tetrahydropyran conformational analysis

2- tetrahydropyran 1-alkyne

2- tetrahydropyran 5-alken

2- tetrahydropyran alkylidenetriarylphosphorane ester

2- tetrahydropyran synthesis

2-Lithio-2- tetrahydropyran

2.3.4- trisubstituted tetrahydropyrans

4- Hydroxy-tetrahydropyran, conformational

4- Methyl-2- tetrahydropyran

4-Iodo tetrahydropyrans

4-Methylene-2,6-disubstituted tetrahydropyrans

7-alkene-1,5-diol tetrahydropyran

A- tetrahydropyranes

Acetal, 17-21, formation tetrahydropyran

Bis[tetrahydropyran-2-ylmethyl

Chair conformation of tetrahydropyran

Chair conformation tetrahydropyran

Cis-2,6-Disubstituted tetrahydropyranes

Condensation, of acetoacetic ester, acid with tetrahydropyran

F Tetrahydropyran

From 2- tetrahydropyrans

Functionally substituted tetrahydropyran

Isoxazolines in tetrahydropyran cyclization

Methoxy-tetrahydropyrane

Methoxy-tetrahydropyrane differences

Nucleophilic substitutions tetrahydropyrans, cyclization

Piperidine tetrahydropyran

Protective groups tetrahydropyran

Pyranones tetrahydropyran-4-ones

Pyrolysis, apparatus for of tetrahydropyran and aniline

Radical tetrahydropyran

Rates tetrahydropyran reaction

Rearrangements from Tetrahydropyran Derivatives

Reduction, by amalgamated zinc and dihydropyrane to tetrahydropyrane

Solvent effects substituted tetrahydropyran

Spectra tetrahydropyran

Stereoselective tetrahydropyrans

Steroidal O-tetrahydropyran-2-yl derivatives

Substituted tetrahydropyran

Substituted tetrahydropyrans

Tetrahydrofuran tetrahydropyran

Tetrahydropyran

Tetrahydropyran

Tetrahydropyran (Pyranose Sugars)

Tetrahydropyran (THP)

Tetrahydropyran , cyclic derivatives

Tetrahydropyran 1,5-alkanediol

Tetrahydropyran Compounds

Tetrahydropyran Oxane

Tetrahydropyran Systems

Tetrahydropyran alkanol

Tetrahydropyran anomeric effect

Tetrahydropyran anomeric effect on reactivity

Tetrahydropyran basicity

Tetrahydropyran conformation

Tetrahydropyran conformation of derivatives

Tetrahydropyran derivatives

Tetrahydropyran enantioselective synthesis

Tetrahydropyran rearrangement

Tetrahydropyran ring

Tetrahydropyran ring strain

Tetrahydropyran structure

Tetrahydropyran-2,3-diester

Tetrahydropyran-2,4-diol

Tetrahydropyran-2-Methanol

Tetrahydropyran-4-ones

Tetrahydropyranal ether

Tetrahydropyrane

Tetrahydropyrane

Tetrahydropyrane derivatives

Tetrahydropyranes

Tetrahydropyranes

Tetrahydropyranes annulated

Tetrahydropyranes diacetoxy

Tetrahydropyranes, anomeric effect

Tetrahydropyranes, synthesis

Tetrahydropyrans

Tetrahydropyrans and Dihydropyrans

Tetrahydropyrans annulation

Tetrahydropyrans conformations

Tetrahydropyrans enantioselective synthesis

Tetrahydropyrans polysubstituted

Tetrahydropyrans radical conformation

Tetrahydropyrans reactions

Tetrahydropyrans rearrangement

Tetrahydropyrans synthesis acetylation

Tetrahydropyrans synthesis cyclization strategies

Tetrahydropyrans synthesis natural products

Tetrahydropyrans synthesis processes

Tetrahydropyrans, 2- substituted synthesis

Tetrahydropyrans, anomeric effect

Tetrahydropyrans, ether transfer

Tetrahydropyrans, stereospecific synthesis

Tetrahydropyrans, substitute

Tetrahydropyrans, synthesis

Tetrahydropyrans. formation

Tris-tetrahydropyran

Vinyl Tetrahydropyrans

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