- Chiral ureas and thioureas supported on polystyrene for enantioselective aza-Henry reactions under solvent-free conditions
-
Novel bifunctional ureas and thioureas immobilized on sulfonylpolystyrene have been prepared as recoverable and reusable organocatalysts and have been used in the stereoselective aza-Henry reaction under solvent-free conditions. The activity and stereoselection of the catalysts are dependent on the length of the tether bridging the active site and the polymer, the catalyst derived from 1,6-hexane diamine being the best one. It has also been demonstrated that the supported catalysts are more effective than the homologous soluble catalysts.
- Pedrosa, Rafael,Andrés, José M.,ávila, Deisy P.,Ceballos, Miriam,Pindado, Rodrigo
-
supporting information
p. 2217 - 2225
(2015/04/22)
-
- Reductive lithiation of 1,3-dimethyl-2-arylimidazolidines
-
Naphthalene catalyzed lithiation of 1,3-dimethyl-2-phenylimidazolidine led to cleavage of the benzylic carbon-nitrogen bond, with formation of an intermediate dianion. Under similar conditions, 1,3-dimethyl-2-(4-chlorophenyl) imidazolidine underwent regioselective cleavage of the aromatic carbon-chlorine bond, leading to a 4-formylphenyllithium equivalent, whilst 1,3-dimethyl-2-(4- methoxymethylphenyl)imidazolidine underwent regioselective cleavage of the benzylic carbon-oxygen bond, leading to a 4-formylbenzyllithium equivalent.
- Azzena, Ugo,Dettori, Giovanna,Pisano, Luisa,Siotto, Immacolata
-
p. 3177 - 3182
(2007/10/03)
-
- 7-[3-(1-piperidinyl)propoxy]chromenones as potential atypical antipsychotics
-
Compound 1 (1-benzyl-3-methyl-4-[4-(4-fluorophenyl)-4- oxobutyl]piperazine), a synthetic intermediate identified as a potential atypical antipsychotic, was selected as the starting point for pharmacological improvement. From 1, sequential structural variations were conducted in order to improve its potency and oral bioavailability. These variations included a series of piperazine, ethanediamine, and piperidine derivatives. The piperidine series afforded some orally potent compounds in the inhibition of apomorphine-induced climbing and hyperactivity in mice, which are regarded as behavioral models predictive of antipsychotic efficacy. Further optimization of these structures led to the highly potent 7-[3-(1- piperidinyl)propoxy]chromenones. Inhibition of stereotypies and induction of catalepsy in rats at doses substantially higher than required for inhibition of climbing suggest an atypical antipsychotic profile, which is assumed to predict a reduced induction of extrapyramidal side effects in humans.
- Bolós, Jordi,Gubert, Santiago,Anglada, Lluís,Planas, Josep M.,Burgarolas, Carme,Castelló, Josep M.,Sacristán, Aurelio,Ortiz, José A.
-
p. 2962 - 2970
(2007/10/03)
-
- Reduction of Substituted 1H-4,5-Dihydroimidazolium Salts
-
Reactions of several substituted 1H-4,5-dihydroimidazolium salts 1 with nucleophilic and electrophilic reducing agents acting via hydride transfer were explored.Reaction of compounds 1 with lithium aluminum hydride in THF afforded the corresponding imidazolidines 2.When alkaline borohydrides (sodium borohydride, potassium borohydride, sodium cyanoborohydride) in ethanol at room temperature were used, partial or total over-reduction of compounds 2 leading to N,N,N'-trisubstituted ethylenediamines took place on occasion.Results may be explained taking into account that reductive cleavage of 2 proceeds via a stabilized iminium ion present in protic solvents.Treatment of compounds 1 with an excess of borane in THF afforded the corresponding imidazolidines 2 or their borane complexes, according to the substituent type.
- Salerno, Alejandra,Ceriani, Vanina,Perillo, Isabel A.
-
p. 1725 - 1733
(2007/10/02)
-
- Synthesis and antihypertensive activity of a series of 4-amino-6,7-dimethoxyquinazoline derivatives
-
A series of N2-[(acylamino)alkyl]-6,7-dimethoxy-2,4-quinazolinediamines was synthesized as potential α1-adrenoceptor antagonists. When administered to spontaneously hypertensive rats at 10 mg/kg po, a number of propanediamine derivatives showed good antihypertensive activity, whereas the ethanediamine derivatives, albeit being structurally more closely related to prazosin, were devoid of this property. The most active derivative, N-[3-[(4-amino-6,7-dimethoxy-2-quinazolinyl)methylamino]propyl]tetrahydro- 2-furancarboxamide hydrochloride, alfuzosin, showed high selectivity for peripheral α1-postjunctional adrenoceptors. At equiactive antihypertensive doses, its effect on the pressor response to postural changes in conscious dog was less marked than that shown by prazosin. In the light of these results, alfuzosin was selected for clinical evaluation.
- Manoury,Binet,Dumas,Lefevre-Borg,Cavero
-
-