2903-75-5Relevant academic research and scientific papers
New and facile synthesis of aminobicyclo[22.1]heptane-2-carboxylic acids
Kim, Taek-Soo,Seo, Seung-Yong,Shin, Dongyun
supporting information, p. 1243 - 1247 (2015/03/31)
Abstract A facile approach for the stereoselective synthesis of a- and b-2-aminobicyclo[2.2.1]heptane-2-carboxylic acid is described. Substrate-controlled α-carboxylation of norbonene monoester delivered the asymmetric diester intermediate with high diastereoselectivity (up to 35:1). Sequential chemoselective ester cleavage, Curtius rearrangement, and hydrolysis gave the a- and b-isomers of 2-aminobicyclo[2.2.1]heptane-2-carboxylic acid, respectively.
Diels-Alder reactions in room-temperature ionic liquids
Fischer,Sethi,Welton,Woolf
, p. 793 - 796 (2007/10/03)
The Diels-Alder cycloaddition reaction between methyl acrylate and cyclopentadiene has been investigated in a number of air and moisture stable ionic liquids. The endo/exo ratio of the reaction has been used as an initial probe of the nature of the solvents.
Novel Potassium-Channel Openers: Preparation and Pharmacological Evaluation of Racemic and Optically Active N-(6-Amino-3-pyridyl)-N'-bicycloalkyl-N"-cyanoguanidine Derivatives
Eda, Masahiro,Takemoto, Tadahiro,Ono, Shin-ichiro,Okada, Takehiro,Kosaka, Keigo,et al.
, p. 1983 - 1990 (2007/10/02)
The previous paper reported on the synthesis and pharmacological evaluation of N-(6-amino-3-pyridyl)-N'-bicycloalkyl-N"-cyanoguanidine derivatives, from among which three compounds were selected as potent potassium-channel openers. In the present study, selected compounds were tested for antagonism of potassium-induced contraction of rat aorta, hypotensive activity in normotensive rats, and diuretic activity in spontaneously hypertensive rats. This led to further evaluation of compound (+/-)-10 and selection of (+)-N-(6-amino-3-pyridyl)-N'-hept-2-yl>-N"-cyanoguanidine ((+)-10) (AL0670) for development as an antihypertensive agent. Although AL0670 is regarded as a pinacidil-type K+-channel opener, it showed different pharmacological and conformational profiles from pinacidil.
Stereoselection in Thermal Asymmetric Diels-Alder Reactions. Electronic vs Steric Effects
Stammen, Blanda,Berlage, Ulrich,Kindermann, Richard,Kaiser, Manfred,Guenther, Barbara,et al.
, p. 6566 - 6575 (2007/10/02)
Experimental evidence was found for an electronic contribution favoring the cisoid conformation of α,β-unsaturated carbonyl compounds in thermal Diels-Alder transition states.
Transformations of unsaturated acyclic sugars into enantiomerically pure norbornene derivatives
Horton, Derek,Usui, Takayuki
, p. 33 - 49 (2007/10/02)
The C7 acyclic unsaturated-sugar ester 1, derived from L-arabinose, and its enantiomer serve as convenient dieneophiles for chirality transfer for synthesis of optically pure carbocyclic derivatives through cycloaddition reactions.Reaction of 1 with cyclopentadiene may be controlled to give preparative access to the 5,6-disubstituted norbornene adducts 4a, 5a and 7a, according to the conditions used.The distribution of the four possible isomeric products from this cycloaddition was quantitated, and the effect of substitutional variation on the precursor dienophile 1 was also examined.Adducts 4a and 5a were transformed into such substituted carbocycles of known absolute configuration as the methyl esters (11 and 12) of norbornene (bicyclohept-2-ene)-6-carboxylic acid and nortricyclane (tricyclo2,6>heptane)-3-carboxylic acid in optically pure form, specifically through decarbonylation reactions using RhCl(PPh3)3 (Wilkinson's complex) and Cl.The optical purity of 12 was established by the use of a chiral lanthanide shift-reagent.
INFLUENCE OF POLAR GROUPS IN THERMAL AND LEWIS ACID PROMOTED ASYMMETRIC DIELS-ALDER ADDITIONS: LACTIC ACID DERIVATIVES AS PRACTICAL HIGHLY SELECTIVE AND CONFIGURATIONALLY DICHOTOMIC REAGENTS
Poll, Thomas,Helmchen, Guenther,Bauer, Bernd
, p. 2191 - 2194 (2007/10/02)
Diels-Alder reactions of the acrylate of (S)-ethyl lactate with cyclopentadiene proceed with diastereoface-selectivity of up to 85:15 (non catalyzed) and 93:7 (TiCl4-promoted).Depending on the Lewis acid, products of inverse configuration are obtained.In conjunction with facile product analysis by LC, effective means for suppression of the polymerization of diene, and virtually epimerization-free ester hydrolysis these findings constitute a method for large scale practical applications of the asymmetric Diels-Alder reaction.
