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Propyl substituent

A ketone vvith a substituent group in its /3 position might be prepared by a conjugate addition of that group to an a,/3-unsaturated ketone. In the present instance, the target molecule has a propyl substituent on the /3 carbon and might therefore be prepared from 2-methyl-2-cyclopentenoneby reaction with lithium dipropylcopper. [Pg.729]

To determine the potentiality of catalyst 72a, various alkenes with methyl, ethyl and iso-propyl substituents in cis or trans orientations relative to the aryl substituent were hydrogenated (Scheme 47). In general, (E)-alkenes produced better results than their cis isomers. [Pg.221]

A compound can be an extrapolation from a structural point of view, such as compound 24 that has a n-butyl substituent in the 3-position while the training set (compounds 1-17) only contain methyl-, ethyl- and n-propyl-substituents (among other non-alkyl substituents). Still, compound 24 is not considered to be an outlier from a statistical point of view. At the same time, compounds 18 and 19 which also contains substituents - in this case in the 5-position -that are not part of the training set are statistical outliers as well as structural outliers. [Pg.401]

While the DCJTB series replaced the active methyl group with tert-butyl or iso-propyl substituents to avoid bis-Knovenagel condensation reactions during the synthesis of DCM or DCJ series, Zhang et al. came up with the idea of using substituted cyclohexane rings to block the reactive site of the pyran ring. They then synthesized a series of 4H-benzopyran-based red emitters (158-160) as shown in Scheme 3.49 [210]. [Pg.344]

The allyl cation thus formed may stabilize itself either by readdition of the leaving group — leading to a 2,3-dihalopropene — or by the addition of a nucleophile. The influences of steric and electronic effects on the stereochemistry and on the solvolysis rates of various alkyl-substituted chlorocyclopropanes have been investigated by Parham and co-workers [165, 166], who could show for example that os-2,3-dipropyl-l,l-dichlorocyclopropane solvolyzes 24 times faster than its trans-isomer, in accordance with predictions based on orbital symmetry arguments. When one propyl substituent of the trans-isomer is replaced by an ethoxy group the rate of solvolysis increases 200 fold. [Pg.61]

As an example of actinide dimeric complexes, the series of compounds [M(0-2,6-z-Pr2C6H3)3]2 970 (M = La, Nd, Sm, Er, U), sterically demanded by z-propyl substituents, were isolated [308,310a] they are held both in the solid state and in solution by 7i-arene interactions ... [Pg.434]

We had shown that homologation of the ethyl substituent of EMDT (63) to an M-propyl group (i.e., 73 Kt = 185 nM) resulted in >10-fold decreased affinity. However, in the benzenesulfonyltryptamine series, affinity was not altered in the absence (i.e., MS-245 Kt = 2.3 nM) or presence (i.e., 74 Kt = 2.5 nM) of a 2- -propyl substituent (93). This was another indication that simple tryptamines and benzenesulfonyltryptamines might be binding differently. [Pg.124]

How an unsymmetrical urea can be prepared from a primary amine with a (diethyl-amino )propyl substituent (A) and ethyl isocyanate is illustrated using the example of compound C. This urea is the starting material for preparing a carbodiimide (see Figure 8.9), which activates carboxylic acids towards heteroatom nucleophiles. [Pg.355]

Disposition in the Body. Rapidly and completely absorbed after oral administration. The main metabolic reactions are hydroxyl-ation at the 2- and 3- positions of the propyl substituent in the side-chain, V-dealkylation, and hydrolysis to form the sulphon-amide metabolite. About 80% of a single oral dose is excreted in the urine in 7 days. During chronic therapy, up to 100% of a dose is excreted in the urine in 24 hours, with about 18% of the dose as unchanged drug, 2% as 4-chlorobenzenesulphonamide, 20% as 4-chlorobenzenesulphonylurea, 55% as 2-hydroxychlor-propamide, and 2% as 3-hydroxychlorpropamide. [Pg.462]

The diastereomerically pure thiazolium salt 509 which bears a 2-/i t7-butylphenyl substituent at the nitrogen atom was converted into a mixture of 510 and its atropisomer 510 (dr = 75 25) upon treatment with base (Scheme 128). The stereogenic center in the intermediate carbene favors one rotamer 510. Upon reaction with benzaldehyde, it accounts in a similar fashion for the formation of the major enol diastereoisomer 511 over 511, which, in turn, leads to the major enantiomer 512 rather than 512 observed in the benzoin condensation catalyzed by 509. The concept of axial chirality was proven to be viable for an efficient chirality transfer. Replacement of the isopropyl group at C-4 by the bulkier 2-phenyl-2-propyl substituent using 8-phenylmenthone is likely thought to increase the ee <2004EJ02025>. [Pg.736]

The affinity of compounds 34 and 35 for the dopamine D2 and D3 receptors is lower than that of 5-OH-DPAT, probably due to the fact that the sulfur atom in the thiophene ring is only a weak hydrogen bond acceptor unlike the hydroxyl moiety of a phenol, which is a strong hydrogen bond acceptor and donor. The fact that compound 39 was more effective compared to compound 38 is most likely due to a better fit into the receptor of the n-propyl substituent of compound 39 than the hydrogen of compound 38. [Pg.81]

Acetohexamideis metabolized by reduction in the liver of its ketone function to an alcohol, hydroxyhexamide, which is pharmacologically active (79,86). After oral administration, the plasma concentration of the parent compound peaks in 1-2 h, then falls rapidly. The active metabolite has a longer half-life and prolongs the duration of action. Hydroxyhexamide is excreted primarily in the urine with a small amount of the parent and other clinically unimportant metabolites. Chlorpropamide is quite long lived in circulation, with an elimination half-life of about 36 h. It is slowly metabolized by hydroxylation at the 2 or 3 position of the propyl substituent, yielding metabolites that retain some activity and by N-dealkylation to p-chlorobenzenesulfonyl-urea (86, 89). Urinary excretion is the main... [Pg.16]

Carbamates - Further studies of the recently marketed tybamate have. been reported. Geller j as placed it between meprobamate and CPZ in its psychopharmacological effectiveness. Although it attenuates punishment discrimination at higher doses than meprobamate, it blocks avoidance responding at doses that do not block escape responses. The absence of withdrawal symptoms, previously observed in the dog, has been demonstrated in man.83 Tybamate is metabolized in the dog and rat principally by conversion of its n-propyl substituent into a 2-hydroxypropyl group.This is accompanied by some N-debutylation. [Pg.5]

Both steric and electronic effects can influence the regioselectivity of ene reactions. For example, a strong preference for hydrogen abstraction from the more substituted side of the double bond of the perepoxide intermediates, generated from trisubstituted alkenes, is observed. This effect has been called the cis effect and explained on the basis of orbital interactions1423 and activation entropy differences.1457 Scheme 6.267 shows the product distribution after photooxygenation of three alkenes (561 563).1461 There is an apparent steric effect of the methyl versus 2-propyl substituents in the first two cases. The cyclopropyl moiety in the last example remains unreacted, which rules out the formation of a biradical intermediate (see also Special Topic 6.10). [Pg.420]


See other pages where Propyl substituent is mentioned: [Pg.547]    [Pg.106]    [Pg.203]    [Pg.257]    [Pg.879]    [Pg.344]    [Pg.230]    [Pg.231]    [Pg.917]    [Pg.581]    [Pg.321]    [Pg.240]    [Pg.678]    [Pg.17]    [Pg.554]    [Pg.577]    [Pg.319]    [Pg.107]    [Pg.122]    [Pg.129]    [Pg.302]    [Pg.302]    [Pg.233]    [Pg.729]    [Pg.221]    [Pg.575]    [Pg.575]    [Pg.409]    [Pg.535]    [Pg.90]    [Pg.74]    [Pg.193]   
See also in sourсe #XX -- [ Pg.1009 ]

See also in sourсe #XX -- [ Pg.962 ]




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