- A Critical Test of the Theory of Stereoelectronic Control
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According to Deslongchamps' theory of stereoelectronic control, preferential cleavage of a tetrahedral intermediate occurs when there are two lone pairs antiperiplanar to the leaving group.However, it is concluded that the experimental evidence is ambiguous, because it requires an unreasonable assumption regarding rates of ring inversion and because there is a simpler explanation for the observations.Nevertheless, the theory is a plausible one, deserving unambiguous evidence to support it.The hydrolysis of cyclic amidines (4), via the hemiorthoamide (5), can provide a suitable test.It is observed that 2-amino-1-pyrroline (4, n = 5) and "2-iminopiperidine" (4, n = 6) hydrolyze in base solely to the amino amide (6), which is converted under the reaction conditions to the thermodynamically more stable lactam (7).This result is the first unambiguous evidence for stereoelectronic control, and it also shows that cleavage of the intermediate (5) is fast compared to nitrogen inversion.
- Perrin, Charles L.,Arrhenius, Gloria Meichia L.
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- NOVEL TETRAHYDROPYRIDOPYRIMIDINES FOR THE TREATMENT AND PROPHYLAXIS OF HBV INFECTION
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The present invention provides novel compounds having general formula (I), wherein R1 to R4, A, W, Q and Y are as described herein, compositions including the compounds and methods of using the compounds.
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- Compounds having growth hormone releasing activity
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Compounds that promote growth hormone releasing activity are disclosed. These compounds have the formula: A1-A2-X; A1-X′; or A1.-Y These compounds can be present in a pharmaceutical composition. The compounds can be used with a second compound that acts as an agonist at the growth hormone releasing hormone receptor or which inhibits the effects of somatostatin. These compounds can be used for a variety of uses such as treating hypothalamic pituitary dwarfism, osteoporosis, burns, or promoting wound healing.
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- Inhibitory effect of 2-(E-2-alkenoylamino)ethyl alkyl sulfides on gastric ulceration in rats. II. Structure and activity relationships of 2(E-n or Z-n-decenoylamino)ethyl alkyl sulfides
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The analogues of 2-(E-n or Z-n-decenoylamino)ethyl carbamoylmethyl sulfide, including the modifications of sulfide portion, double bond in decenoyl chain and alkyl sulfide moiety, were synthesized and their inhibitory effects on stress-induced ulceration in rats were compared. Replacing the sulfura atom by methylene group or oxygen atom reduced the effect of potency. Saturation of the double bond in the decenoyl chain tended to reduce the anti-ulcerogenic activity in rats. There was no relationship between the position of double bond in decenoyl chain and the pharmacological activity. On the other hand, compounds with E-configuration showed stronger anti-ulcer activity than the corresponding Z-type of compounds. Among 9 kinds of S substituted alkyl groups for carbamoylmethyl, 2-(E-2-decenoylamino)ethyl 2-cyclohexylethyl sulfide showed the most potent anti-ulcerogenic activity in rats and also showed the lowest acute toxicity in mice.
- Kohda,Iwai,Watanabe,Arakawa,Fukaya,Yokoyama,Kohama,Mimura
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p. 1546 - 1550
(2007/10/02)
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