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ABSTRACT: The relative reactivity of a systematic series of simple aliphatic acetate esters has been measured. Exposure of pairs of esters of increasing remote steric hindrance (by altering the degree of branching of the ester alkyl group) to a methanolic solution of Cs2CO3 proved to be a reliable (and general) method for quantitating the rate differences in these base-catalyzed transesterification reactions. The trends in relative rates are in accordance with the qualitative "Rule of Six" put forward by Melvin S. Newman in 1950, as deduced then from interpretation of earlier reports of ease of Fischer esterification reactions.
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Intramolecular Capture of HDDA-Derived Benzynes: (i) 6- to 12-Membered Ring Formation, (ii) Internally (vis-à-vis Remotely) Tethered Traps, and (iii) Role of the Rate of Trapping by the Benzynophile
- Award ID(s):
- 1665389
- PAR ID:
- 10059518
- Date Published:
- Journal Name:
- Organic Letters
- Volume:
- 20
- Issue:
- 1
- ISSN:
- 1523-7060
- Page Range / eLocation ID:
- 88 to 91
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Background: Recent reports have raised concern about the risk of vessel wall injury (VWI) when pulling out current laser-cut stent retrievers with active strut apposition to the vessel walls. Development of braided stroke thrombectomy-assist devices for use in conjunction with aspiration systems may be gentler in the internal carotid (ICA) and basilar vessels (with regards to radial force) compared to existing laser-cut stent retrievers. Methods: Radial force (RF) bench testing was performed using a radial compression station (Blockwise Engineering, Phoenix, AZ). The average total radial force (RF) in Newtons (N) generated (average of 3 readings) in vessel diameters (d) (Range 3.25 to 4.00mm) seen in proximal LVOs of the anterior circulation (such as in the internal carotid artery - ICA), and vessel diameters (d) (Range 2.50 to 3.25mm) seen in the posterior circulation (such as in the basilar artery - BA) was measured. The Solitaire Platinum Revascularization Device (Medtronic, Irvine, CA) was used as the predicate device. All thrombectomy and thrombectomy-assist devices were compared in terms of the RF being higher or lower (%) to the predicate device. Results: The results of the radial force testing are shown in the table below. The total radial force (RF) of the SHELTER® Retriever (part of Insera System, Insera Therapeutics, Inc., Dallas, TX), a braided thrombectomy-assist device is significantly lower (@ d=2.5mm: 58%) than the predicate device (@ d=2.5mm: 100%) and other laser-cut stent retrievers (@ d=2.5mm: 103% to 152%). Thrombectomy devices with lower OD had higher radial forces than larger devices. Conclusion: Novel braided stroke thrombectomy-assist devices for use in conjunction with aspiration systems have lower radial force compared to existing laser-cut stent retrievers in the ICA and BA vessel diameters. Further studies in-vivo need to assess the impact of lower radial force on minimizing VWI. Funding Source: This study was funded in part by a research grant (NSF Award: 1819491; PI: Vallabh Janardhan, MD) from the National Science Foundation (NSF). Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation. Conference Proceeding: This paper was presented in part at the 2018 Annual Meeting of the Society of Vascular & Interventional Neurology (SVIN), November 14-17, 2018 in San Diego, CAmore » « less
- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1021/acs.orglett.7b03436
