The Experts below are selected from a list of 111 Experts worldwide ranked by ideXlab platform
Hokoon Park - One of the best experts on this subject based on the ideXlab platform.
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Asymmetric synthesis of both enantiomers of novel tetracyclic heterocycle, furo[3′,2′:2,3]pyrrolo[2,1-a]Isoquinoline Derivative via a diastereoselective N-acyliminium ion cyclization
Tetrahedron, 1997Co-Authors: Bong Young Chung, Hokoon ParkAbstract:Abstract An efficient synthesis of both enantiomers of tetracyclic Isoquinoline Derivative (−)- 2 and (+)- 2 was accomplished starting from L-malic acid and L-tartaric acid, respectively. The key step is the stereoselective introduction of quaternary carbon-center in ring juncture using a diastereoselective N -acyliminium ion cyclization of chiral enamides ( 1, 3 ).
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asymmetric synthesis of both enantiomers of novel tetracyclic heterocycle furo 3 2 2 3 pyrrolo 2 1 a Isoquinoline Derivative via a diastereoselective n acyliminium ion cyclization
Tetrahedron, 1997Co-Authors: Bong Young Chung, Hokoon ParkAbstract:Abstract An efficient synthesis of both enantiomers of tetracyclic Isoquinoline Derivative (−)- 2 and (+)- 2 was accomplished starting from L-malic acid and L-tartaric acid, respectively. The key step is the stereoselective introduction of quaternary carbon-center in ring juncture using a diastereoselective N -acyliminium ion cyclization of chiral enamides ( 1, 3 ).
Bong Young Chung - One of the best experts on this subject based on the ideXlab platform.
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Asymmetric synthesis of both enantiomers of novel tetracyclic heterocycle, furo[3′,2′:2,3]pyrrolo[2,1-a]Isoquinoline Derivative via a diastereoselective N-acyliminium ion cyclization
Tetrahedron, 1997Co-Authors: Bong Young Chung, Hokoon ParkAbstract:Abstract An efficient synthesis of both enantiomers of tetracyclic Isoquinoline Derivative (−)- 2 and (+)- 2 was accomplished starting from L-malic acid and L-tartaric acid, respectively. The key step is the stereoselective introduction of quaternary carbon-center in ring juncture using a diastereoselective N -acyliminium ion cyclization of chiral enamides ( 1, 3 ).
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asymmetric synthesis of both enantiomers of novel tetracyclic heterocycle furo 3 2 2 3 pyrrolo 2 1 a Isoquinoline Derivative via a diastereoselective n acyliminium ion cyclization
Tetrahedron, 1997Co-Authors: Bong Young Chung, Hokoon ParkAbstract:Abstract An efficient synthesis of both enantiomers of tetracyclic Isoquinoline Derivative (−)- 2 and (+)- 2 was accomplished starting from L-malic acid and L-tartaric acid, respectively. The key step is the stereoselective introduction of quaternary carbon-center in ring juncture using a diastereoselective N -acyliminium ion cyclization of chiral enamides ( 1, 3 ).
J Hescheler - One of the best experts on this subject based on the ideXlab platform.
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the Isoquinoline Derivative loe 908 selectively blocks vasopressin activated nonselective cation currents in a7r5 aortic smooth muscle cells
Naunyn-schmiedebergs Archives of Pharmacology, 1994Co-Authors: D Krautwurst, Vadim E Degtiar, Gunter Schultz, J HeschelerAbstract:The effect of (R,S)-(3,4-dihydro6,7-dimethoxyIsoquinoline-1-yl)-2-phenyl-N,N-di- [2- (2, 3,4-trimethoxyphenyl)ethyl]-acetamide (LOE 908), a cation channel blocker in HL-60 promyeloblasts, was studied in the A7r5 smooth muscle cell line from rat thoracic aorta, using the whole-cell patch-clamp technique. At a holding potential of −60 mV, application of vasopressin induced a nonselective cation conductance in voltage-clamped A7r5 cells. The current-voltage relation was linear, and currents reversed close to 0 mV regardless of the chloride gradient. The activation of the nonselective cation conductance by vasopressin was not affected by dialysing cells with Ca+-free internal solution. LOE 908 blocked this current in a concentration-dependent manner with an IC50 of 560 nM, whereas dihydropyridine-sensitive Ba2+ current through voltage-dependent Ca2+ channels was blocked with an IC50 of 28 μM. Another organic blocker of receptor-mediated Ca2− entry, 1-β-[3-(4-methoxyhenyl)-propoxy]-4-methoxyphenethyl-1H-imidazole hydrochloride (SK&F 96365), blocked both, the vasopressin-induced nonselective conductance and the voltage-activated Ba2+ current with similar IC50 values of 13 μM and 8 μM, respectively. The rank order of potency of inorganic blockers on the vasopressin-induced inward current was Gd3+>La3+>Cd2+. Vasopressin-induced nonselective cation current was also observed in pertussis toxin-pretreated A7r5 cells but was completely abolished after infusion of the GDP analogue, guanosine 5′-O-[3-thio]diphosphate, from the patch pipette. Furthermore, vasopressin induced a transient outward current, suggesting a Cau2+-activated K+-current, which overlapped with the nonselective cation conductance. The outward current was blocked by internal Cs+ and external Ba2+ or TEA.
Chuichi Kawai - One of the best experts on this subject based on the ideXlab platform.
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a new type of vasodilator ha1077 an Isoquinoline Derivative inhibits proliferation of bovine vascular smooth muscle cells in culture
Journal of Pharmacology and Experimental Therapeutics, 1991Co-Authors: Manabu Shirotani, Ryuichi Hattori, Chuichi KawaiAbstract:The effects of a newly developed vasodilator agent, HA1077 [1-(5-Isoquinolinesulfonyl)-homopiperazine hydrochloride], were investigated on the proliferation of cultured bovine aortic vascular smooth muscle cells (VSMC). HA1077 (10-100 microM) inhibited both fetal calf serum-induced proliferation and [3H]thymidine incorporation into DNA of the growth-arrested VSMC in a dose-dependent manner. When quiescent cells were stimulated with platelet-derived growth factor followed by insulin, HA1077 (1-30 microM), administered together with either stimulation, showed dose-dependent inhibition of [3H]thymidine incorporation. Further reduction of [3H]thymidine incorporation was observed when HA1077 was present at both stimulations, suggesting that HA1077 suppresses DNA synthesis acting in both competence and progression stages. After stimulation with fetal calf serum, quiescent VSMC started and ceased DNA synthesis in 15 to 18 hr and 24 hr, respectively. HA1077 inhibited [3H]thymidine incorporation when it was added either from 12 hr to 15 hr or from 21 hr to 24 hr after serum stimulation. In addition, when percent inhibition of [3H]thymidine incorporation by continuous exposure to HA1077 was examined as a function of the time it was added, reductions of the value were observed at 0 to 3 hr, 12 to 18 hr and 21 to 24 hr. Thus, we concluded that HA1077 suppresses DNA synthesis of bovine VSMC acting at the G0/G1 and the G1/S phase transitions and also in the S phase of the cell cycle. It is suggested that this agent may act as a potent inhibitor of VSMC proliferation as well as a vasodilator.
Klaus Groschner - One of the best experts on this subject based on the ideXlab platform.
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inhibition of a store operated ca2 entry pathway in human endothelial cells by the Isoquinoline Derivative loe 908
British Journal of Pharmacology, 1996Co-Authors: A Encabo, Christoph Romanin, F W Birke, Walter R Kukovetz, Klaus GroschnerAbstract:Abstract 1. The novel cation channel blocker, LOE 908, was tested for its effects on Ca2+ entry and membrane currents activated by depletion of intracellular Ca2+ stores in human endothelial cells. 2. LOE 908 inhibited store-operated Ca2+ entry induced by direct depletion of Ca2+ stores with 100 nM thapsigargin or 100 nM ionomycin with an EC50 of 2 microM and 4 microM, respectively. 3. LOE 908 did not affect thapsigargin- or ionomycin-induced Ca2+ release from intracellular stores up to concentrations of 3 microM. 4. LOE 908 reversibly suppressed thapsigargin- as well as ionomycin-induced whole-cell membrane currents. 5. The LOE 908-sensitive membrane conductance corresponded to a cation permeability of 5.5 and 6.9 fold selectivity for Ca2+ over K+ in the presence of thapsigargin and ionomycin, respectively. 6. Our results suggest that the Isoquinoline, LOE 908 is a novel, potent inhibitor of the store-operated (capacitive) Ca2+ entry pathway in endothelial cells.