ADVERTISEMENT RETURN TO ISSUEPREVNoteNEXTPreparation and Use of a Polymer Supported BINAP Hydrogenation CatalystDaniel J. Bayston, Joanne L. Fraser, Mark R. Ashton, Anthony D. Baxter, Mario E. C. Polywka, and Edwin MosesView Author Information Oxford Asymmetry International plc, 151 Milton Park, Abingdon, Oxon OX14 4SD, U.K. Cite this: J. Org. Chem. 1998, 63, 9, 3137–3140Publication Date (Web):April 7, 1998Publication History Received30 December 1997Published online7 April 1998Published inissue 1 May 1998https://doi.org/10.1021/jo972330gCopyright © 1998 American Chemical SocietyRIGHTS & PERMISSIONSArticle Views1341Altmetric-Citations117LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit Read OnlinePDF (79 KB) Get e-AlertscloseSUBJECTS:Catalysts,Hydrocarbons,Hydrogenation,Organic compounds,Polymers Get e-Alerts

A general procedure for the preparation of S-nucleosidyl S-aryl disulfides from the corresponding thioesters is described. This procedure has been used for the preparation of a ribonucleoside disulphide (8d), a key intermediate for the synthesis of oligoribonucleotides containing 3′-S-phosphorothiolate linkages. The regioselectivity of the Arbusov reaction of 8d with phosphites has been examined. The X-ray structure of 3′-deoxy-3′-S-(2-nitrophenyldisulfanyl)thymidine (9b) is also reported.

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SANDLER, A. N.; BAXTER, A. D.; KATZ, J.; SAMSON, B.; FRIEDLANDER, M.; NORMAN, P.; KOREN, G.; ROGER, S.; HULL, K.; KLEIN, J. Author Information

The 5'-O-monomethoxytrityl-3'-S-(aryldisulfanyl)-3'-deoxythymidines 7 and 8 have been prepared by the reaction of 5'-O-monomethoxytrityl-3'-thiothymidine with the appropriate arenesulfenyl chloride. These disulfides undergo a Michaelis-Arbusov reaction with simple trialkyl phosphites to yield 5'-O-monomethoxytrityl-3'-thiothymidin-3'-yl O,O-dialkyl phosphorothiolates. More interestingly, 3'-deoxy-3'-S- (2,4-dinitrophenylsulfanyl)-5'-O-monomethoxytritylthymidine 8 reacts with a variety of thymidin-5'-yl dialkyl phosphites to give dithymidine phosphorothiolate triesters with the phosphorothiolate group protected with either a methyl or a 2-cyanoethyl group.3'-O-(tert-Butyldimethylsilyl)thymidin-5'-yl triethylammoniumphosphonate 17 is converted into the corresponding bis-(O-trimethylsilyl) phosphite by treatment with bis(trimethylsilyl)trifluoroacetamide. in situ Reaction of this phosphite with disulfide 8 gives, after work-up, the dithymidine phosphorothiolate diester directly. Methylation of compound 17 with methyl chloromethanoate, followed by silylation and subsequent reaction with disulfide 8, gives the methyl-protected dithymidine phosphorothiolate triester.

BACKGROUND AND OBJECTIVES:Until the arrival of microcatheters, continuous spinal anesthesia was mainly restricted to elderly and high-risk patients. The introduction of microcatheters enabled the technique to be used in a wider range of patients. This paper describes the experiences of anesthetists in Canada with these catheters, and the changes in their practice since their withdrawal. METHODS:Anesthetists (those known to have experience with continuous spinal anesthesia, or to be regional anesthesia enthusiasts) across Canada were surveyed by telephone or mail. RESULTS:Of a total of 36 respondents, 25 had tried continuous spinal anesthesia with microcatheters. The majority had experience of only a few cases but a few reported larger series of hundreds of cases, Numerous technical difficulties with catheter insertion occurred, and problems with catheter breakage and neurologic deficit were reported. Some of these problems were reported to the Health Protection Branch, and, as a result of these reports and problems experienced in the United States, microcatheters were recalled in Canada soon after the FDA safety alert in the United States. CONCLUSIONS:Various techniques are being used instead of continuous spinal anesthesia with microcatheters, and only a few anesthetists favored their return.

The analgesic efficacy and sideeffects of epidural nalbuphine (0.075– 0.3 mg · kg−1) were compared with epidural morphine 0.1 mg · kg−1 in a randomised doubleblind study in postthoracotomy patients. The drugs were administered via a lumbar epidural catheter one hour before the end of surgery. Efficacy was assessed using visual analogue pain scores and supplementary iv fentanyl requirements; respiratory function was studied with an inductive plethysmograph and arterial blood gas analysis; and plasma nalbuphine levels were measured.

The provision of analgesia using continuous bilateral intercostal blockade was compared with that provided by conventional i.v. narcotics for the first 48 h after cardiac surgery. The subjective quality of analgesia was significantly superior with the regional technique. However, pulmonary function tests, gas exchange, lung volume, and radiological and clinical evidence of pulmonary complications were not improved. The failure to reduce morbidity and the potential for complications such as pneumothorax, makes it difficult to recommend the regional analgesia technique in this situation.

1Department of Anesthesia Ottawa General Hospital 501 Smyth Road Ottawa, Ontario, Canada K1H 8L6 (Baxter) 2Assistant Professor of Surgery (Urology) Department of Surgery The Health Sciences Centre Memorial University of Newfoundland St. John's, Newfoundland, Canada A1B 3V6 (Kiruluta)

Epidural morphine has found increasing popularity in clinical trials for the relief of chronic and postoperative pain relief. This study was conducted to determine if there was any adverse tissue reaction when morphine was applied to the epidural space of dogs. Sixteen dogs were given 0.07 mg X kg-1 of morphine in a volume of 2 cc of normal saline into the epidural space. Gross and microscopic studies of the epidural space, dura, and spinal cord did not show any adverse tissue reaction.