- Quinazoline Derivatives by Cyclodehydrogenation of N-(2-Substituted Aryl)-Piperidines
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Dehydrogenation of the N-[2-(aminocarbonyl)phenyl]piperidines 1-5 using Hg(II)-EDTA, generated the quinazolinones 6-9. Increasing size of the 4-substituent in the piperidine decreased the oxidation rate and the product yield. N-[2-(Hydroxyiminomethyl)phenyl]piperidines 18-22 showed a different behaviour. While 18 with Hg(II)-EDTA in water produced the oxime lactam 24 in quantitative yield, the 4-substituted piperidines 19-21 caused not only a lower reaction rate but also an altered product pattern. The double dehydrogenation to lactams was reduced and the cyclic nitrones, formed by two electron withdrawal, became dominant. From the spiro compounds 21 and 22, solely the quinazoline-N-oxides 29 and 30 resulted. The mechanism of the reactions is discussed.
- M?hrle,Jeandrée
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p. 1577 - 1588
(2007/10/03)
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- Repaglinide and related hypoglycemic benzoic acid derivatives
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The structure-activity relationships in two series of hypoglycemic benzoic acid derivatives (5, 6) were investigated. Series 5 resulted from meglitinide (3) when the 2-methoxy was replaced by an alkyleneimino residue. Maximum activity was observed with the cis-3,5-dimethylpiperidino (5h) and the octamethyleneimino (5l) residues. Series 6 resulted from the meglitinide analogon 4 bearing an inversed amido function when the 2-methoxy, the 5- fluoro, and the α-methyl residue were replaced by a 2-piperidino, a 5- hydrogen, and a larger α-alkyl residue, respectively. An alkoxy residue ortho to the carboxy group further increased activity and duration of action in the rat. The most active racemic compound, 6al (R4 = isobutyl; R = ethoxy), turned out to be 12 times more active than the sulfonylurea (SU) glibenclamide (1). Activity was found to reside predominantly in the (S)- enantiomers. Compared with the SUs 1 and 2 (glimepiride), the most active enantiomer, (S)-6al (AG-EE 623 ZW; repaglinide; ED50 = 10 μg/kg po), is 25 and 18 times more active. Repaglinide turned out to be a useful therapeutic for type 2 diabetic patients; approval was granted recently by the FDA and the EMEA. From investigations on the pharmacophoric groups in compounds of type 5 and 6, it was concluded that in addition to the two already known - the acidic group (COOH; S02NH) and the amidic spacer (CONH; NHCO) - the ortho residue R1 (alkyleneimino; alkoxy; oxo) must be regarded as a third one. A general pharmacophore model suitable for hypoglycemic benzoic acid derivatives, SUs, and sulfonamides is proposed (Figure 6). Furthermore, from superpositions of low-energy conformations (LECs) of 1, 2, and (S)-6al, it was concluded that a common binding conformation (LEC II; Figure 10B) may exist and that differences in binding to the SU receptor and in the mechanism of insulin release between repaglinide and the two SUs may be due to specific hydrophobic differences.
- Grell, Wolfgang,Hurnaus, Rudolf
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p. 5219 - 5246
(2007/10/03)
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- The Stereochemistry of Organometallic Compounds. XL. Rhodium-Catalysed Reactions of Hydrogen and Carbon Monoxide with Alkenylanilines
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Rhodium-catalysed reactions of o- or p-cyano-N-allylanilines with H2/CO give N-arylpyrrolidine aldehydes resulting from a double hydroformylation sequence.In contrast reactions of o- or p-methyl-N-allylanilines or N-allylaniline itself with H2/CO give 'dimeric' compounds resulting from self-condensation reactions of an initially formed hydroformylation product together with varying amounts of the double hydroformylation product.Similar reactions of o-cyano-N-but-3-enylanilines give low yields of double hydroformylation products and major products arising from hydrogenation or cross coupling of intermediate enamines.The structure of one of these products, N-2-cyanophenyl-5-(N'-2-cyanophenyl-3-methylpyrrolidin-2-yl)-1,2,3,4-tetrahydropyridine (17) (IUPAC name: 2--1,2,3,4-tetrahydropyridin-1-yl>benzonitrile) was confirmed by an X-ray single-crystal structure determination.
- Anastasiou, Despina,Campi, Eva M.,Chaouk, Hassan,Fallon, Gary D.,Jackson, W. Roy,et al.
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p. 1043 - 1060
(2007/10/02)
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