Improved procedures for the preparation of (+) - (1R, 2S, 4R)-4-amino-2-hydroxy-1-hydroxymethyl cyclopentane

Bray, Brian L.; Dolan, Simon; Halter, B.; Lackey, J. W.; Schilling, Mark B.; Tapolczay, David J.

doi:10.1016/0040-4039(95)00764-4

Cited by 26 publications

(17 citation statements)

References 15 publications

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“…In addition, the use of the (−)-enantiomer of the lactam 228 as the precursor of the anti-HIV agent (−)-carbovir has been described in full (Scheme ) . A method for the stereospecific synthesis of the 4-amino-2-hydroxy-1-hydroxymethylcyclopentane [(+)- 232 ] was described starting from lactam (−)- 228 by the Glaxo research group . These short and efficient syntheses provide rapid access to key intermediate (+)- 232 in the construction of 2‘-deoxy carbocyclic nucleosides.…”

Section: Five-member Ring1 Precursor Resolution By Enzymatic Hydrolys...mentioning

confidence: 99%

Biocatalytic Selective Modifications of Conventional Nucleosides, Carbocyclic Nucleosides, and C-Nucleosides

2000

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Section: Five-member Ring1 Precursor Resolution By Enzymatic Hydrolys...mentioning

confidence: 99%

Biocatalytic Selective Modifications of Conventional Nucleosides, Carbocyclic Nucleosides, and C-Nucleosides

2000

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“…Das gilt in besonderem Maße für die Hydroarylierung der 7‐aza‐ und oxabicyclischen Alkene 2 2b–d, 3c (Schema ), da diese Syntheseroute auch in der asymmetrischen Variante schnell zu dem biologisch hochaktiven Alkaloid Epibatidin4 und seinen Analoga führt. Da wir sowohl an der Hydroarylierung bicyclischer Alkene selbst wie an dem anschließenden Einsatz dieser Produkte zur stereoselektiven Synthese substituierter Cyclopentanderivate interessiert sind, haben wir die Hydroarylierung mit nachfolgender reduktiver Spaltung der gut zugänglichen5 2,3‐Diazabicyclo[2.2.1]heptene 3 untersucht,6 bei denen die N ‐ N‐7 oder C‐N‐Bindung8 eine Sollbruchstelle darstellt.…”

Section: Methodsunclassified

RIMS analysis of Ca and Cr in Genesis solar wind collectors

Veryovkin

Tripa

Zinovev

et al. 2011

Surface & Interface Analysis

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RIMS depth profiles have been measured for Cr and Ca in Genesis solar wind collector made from Si and compared to such measurements for ion-implanted Si reference material. The presence of surface contamination has been shown to be a significant factor influencing the total Ca and Cr fluence measured in the Genesis collectors. A procedure to remove the contaminant signal from these depth profiles using the reference material implanted with a minor isotope demonstrated that 36% of the measured Ca fluence in our Genesis sample comes from terrestrial contamination.

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“…As we are interested in both the hydroarylation of bicyclic alkenes and, herein, in the use of these products in the stereoselective synthesis of substituted cyclopentane derivatives, we have investigated the hydroarylation followed by reductive cleavage of the easily accessible5 2,3‐diazabicyclo[2.2.1]heptenes 3 ,6 in which the NN7 or CN bond8 represents an internal point of fracture.…”

Section: Methodsmentioning

confidence: 99%

Two-Step, Stereoselective Hydrazidoarylation of 1,3-Cyclopentadiene

Yao

Adiwidjaja

Kaufmann

2002

Angew. Chem. Int. Ed.

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The first palladium-catalyzed reductive phenylation of norbornene (1) was published by Larock and Johnson [1] in 1989; since then the high synthetic potential of the hydroarylation [2] and especially its asymmetric variant [3] with bicyclic alkenes for the one-step construction of three asymmetric centers has induced a line of follow-up papers. This situation is especially true for the hydroarylation of the 7-aza-and oxabicyclic alkenes 2 (Scheme 1) [2b±d, 3c] as this synthetic route even in the case of the asymmetric pathway leads directly to the biologically highly active alkaloid Epibatidine [4] and its analogues.As we are interested in both the hydroarylation of bicyclic alkenes and, herein, in the use of these products in the stereoselective synthesis of substituted cyclopentane derivatives, we have investigated the hydroarylation followed by reductive cleavage of the easily accessible [5] 2,3-diazabicyclo[2.2.1]heptenes 3, [6] in which the N À N [7] or C À N bond [8] represents an internal point of fracture.Recently, we have reported the first palladium-catalyzed hydroarylation of the N,N'-diethoxycarbonyl-substituted derivative 4 of 3 with triethylamine as a base. [6] The following selective NÀN bond cleavage opens a highly stereoselective way to the trans-4-aryl-cis-1,3-diaminocyclopentanes 6 (Scheme 2).Encouraged by this initial result, we turned to the hydroarylation of the sterically more hindered and more rigid, trior tetracyclic Diels±Alder adducts of 1,3-cyclopentadiene with the very reactive azodienophiles 4-phenyl-1,2,4-triazoline-3,5-dione (7 a) and 2,3-phthalazine-1,4-dione (7 b). The reaction of 7 a with iodobenzene was chosen as a model system with which to optimize the reaction conditions; selected experiments are shown in Table 1.We started with the reaction conditions (Et 3 N, DMF, 65 8C, entry 1) which were optimal in case of the hydroarylation of 4; besides 21 % of the expected hydroarylation product 8 a, compound 9 a was formed in 9 % as the product of a CÀN cleavage reaction. Formally, the formation of 9 a is the result of a 1,2-hydrazidoarylation on the primarily employed 1,3-cyclopentadiene. From the 1 H and 13 C NMR spectroscopic data it appeared that the trans isomer 9 a was formed exclusively. The structural assignment is difficult in case of five-membered ring systems; however, the stereochemistry was unambiguously supported by an X-ray analysis (Figure 1). [9,10] COMMUNICATIONS

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Improved procedures for the preparation of (+) - (1R, 2S, 4R)-4-amino-2-hydroxy-1-hydroxymethyl cyclopentane

Cited by 26 publications

References 15 publications

Biocatalytic Selective Modifications of Conventional Nucleosides, Carbocyclic Nucleosides, and C-Nucleosides

Biocatalytic Selective Modifications of Conventional Nucleosides, Carbocyclic Nucleosides, and C-Nucleosides

RIMS analysis of Ca and Cr in Genesis solar wind collectors

Two-Step, Stereoselective Hydrazidoarylation of 1,3-Cyclopentadiene

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