4- Methyl-2- tetrahydropyran

A number of pyrans, including 3-hydroxy-tetrahydropyran (both axial conformer, 29 and equatorial conformer, 30), 2-methoxy-tetrahydropyran 33, 3-methyl-tetrahydropyran 32, and several 4-substituted tetrahydropyrans, along with 2-methyl-l,3-dioxolane and the rigid cyclic ethers 7-oxabicyclo[2.2.1]heptane and 1,8-cineole, were studied extensively by NMR. These empirical results, in conjunction with the literature data for a variety of acyclic and cyclic ethers, were used to examine the reliability of O-substituent chemical shift models in these systems. The empirical data correlate well with predictions made from the model and it is concluded that ethereal oxygen substituent chemical shifts are due to both steric and electrostatic terms <1998J(P2)1751>. 

Methyl- tetrahydrofuran-2- -diethylester E2, 359 2-Methyl-tetrahydropyran-2- -diethylester E2, 359 2-Methyl-l,3-thiazol-4-ylmethan- -diethylester XII/1, 445... 

C8H1602 2-ethoxy-4-methyl-tetrahydropyran 25724-34-9 350.30 29.709 1,2 15308 C8H17NO 4-butyl morpholine 1005-67-0 486.65 42.603 1.2... 

A tetrahydropyran that inhibits leukotriene biosynthesis Asymmetric synthesis of2-methyl-tetrahydropyran-4-one by kinetic resolution Part VI - Asymmetric Desymmetrisation of a Diels-Alder Adduct Ifetroban sodium a thromboxane receptor antagonist A laboratory synthesis starting with a Diels-Alder reaction Desymmetrisation of a symmetrical anhydride with a chiral Grignard reagent Laboratory and process routes compared Part VII - Asymmetric Synthesis of A Bicyclic 3-Lactone Lactacystin a naturalproteasome inhibitor... 

Asymmetric synthesis of2-methyl-tetrahydropyran-4-one by kinetic resolution... 

Because human evaluations are nearly always hedged about with qualifications, there is usually some uncertainty in where the boundaries of a given odor class should be drawn. Thus, for example, six professional perfumers when asked to rate the degree of "green" and "rose" character in the compound "rose oxide" or 2-(2-methyl-l-propenyl)-4-methyl-tetrahydropyran, gave the following evaluations. 

This synthesis came shortly after one by Prelog, Kohlberg, Cerkovnikov, Rezek and Piantanida (1937) based on a series of reactions which, with modifications and extensions. Prelog and his colleagues have applied to the syntheses of bridged heterocyclic nuclei, of which this is an example. 4-Hydroxymethyltetrahydropyran (VI R =. OH) is converted via the bromo-compound (VI R = Br) and the nitrile (VI R = CN) into tetrahydropyran-4-acetic acid of which the ethyl ester (VII) is reduced to 4-()3-hydroxyethyl)-tetrahydropyTan (VIII). This is converted by fuming hydrobromic acid into 3-(2-bromoethyl)-l 5-dibromopentane (IX) which with ammonia in methyl alcohol yields quinuclidine (V). 

Butyl alcohol, n-butyraldehyde, methyl ethyl ketone, 2-meth-ylfuran, tetrahydrofuran, 4-methyl-l,3-dioxolane, 2-methyl THF, 3-methyl THF, and tetrahydropyran... 

As a strategy for the construction of cyclic ethers, the radical cyclization of jS-alkoxyacrylates was used for the preparation of czs-2,5-disubstituted tetrahy-drofurans and cis-2,6-disubstituted tetrahydropyrans. An example is given with S-alkoxymethacrylate 38 as precursor of the optically active benzyl ether of (+)-methyl nonactate, exclusively formed as the threo product (Reaction 44). ° ... 

C24H25NO3S) see Saquinavir 2,2, 2",2 "-[(l,2,3,4-tetrabydro-8-piperidinopyrimido [5,4-(7]pyrimidine-2,6-diyl)dinitrilo]tetraetbanol (C19H35N7O4 13665-89-9) see Mopidamol tetrahydropyran-4-carbonyl chloride (CfjH9C102 40191-32-0) see Risperidone tetrahydropyran-4-carboxylic acid (C(jHio03 5337-03-1) see Risperidone [2-[(tetrahydro-2H-pyran-2-yl)oxy]ethyl]carbamodithioic acid methyl ester... 

Methyl-Tbu1ene 2-Methyl-2-butene Cyclopentanol Tetrahydropyran Penlanai... 

A disadvantage of the THP group is the fact that a new stereogenic center is produced at C(2) of the tetrahydropyran ring. This presents no difficulties if the alcohol is achiral, since a racemic mixture results. However, if the alcohol is chiral, the reaction gives a mixture of diastereomers, which may complicate purification and/or characterization. One way of avoiding this problem is to use methyl 2-propenyl ether in place of dihydropyran (abbreviated MOP, for methoxypropyl). No new chiral center... 

Haworth methylation of methyl /3-D-glucopyranoside and its 4-benzyl and 4-(tetrahydropyran-2-yl) ethers was investigated in connection with partial-methylation studies on cellulose.267 For the unsubstituted glycoside, the ratios of relative rate-constants k2 k3 k4 k were estimated to be 8 2 1 8, and, for the 4-ethers, it was found that ke> k2> k3 best agreements between calculated and experimental yields were found with the assumption that the rate constant for reaction at HO-3 is doubled when HO-2 is substituted. Later methylation studies,268 performed to low degrees of substitution, with analysis by gas-liquid chromatography, gave k2> k4> k3 for the reactivity... 

As these acetals could be converted into the 4,6-O-ethylidene derivatives on treatment with acid, it was reasoned that use of a cyclic vinyl ether, namely, 3,4-dihydro-2H-pyran, might prevent this second process, thus leading to a more useful method of selective acetalation.338 An equimolar reaction with methyl a-D-glu-copyranoside for 4 days in N,N-dimethylformamide led to utilization of 88% of the glycoside, and the 6-(tetrahydropyran-2-yl) ether constituted —85% of the crude reaction-product. In contrast to the steric control apparent in this instance, reaction of 3,4-dihydro-2H-pyran with the axial and equatorial hydroxyl groups in dl-1,4,5,6-tetra-O-acetyl-mi/o-inositol was completely unselective,339 a fact that has been rationalized310 in terms of the probable mechanism of these reactions. 

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