A new convenient route for direct trifluoromethylation of steroidal compounds is described. Steroidal alkenyl bromides, derived from steroidal unsaturated ketones, react with FO2SCF2CO2Me in the presence of CuI in DMF to give the corresponding trifluoromethylated steroids in good yields (70–91%).
{"title":"New, convenient route for trifluoromethylation of steroidal molecules","authors":"X. Fei, W. Tian, Qing‐Yun Chen","doi":"10.1039/A706552C","DOIUrl":"https://doi.org/10.1039/A706552C","url":null,"abstract":"A new convenient route for direct trifluoromethylation of steroidal compounds is described. Steroidal alkenyl bromides, derived from steroidal unsaturated ketones, react with FO2SCF2CO2Me in the presence of CuI in DMF to give the corresponding trifluoromethylated steroids in good yields (70–91%).","PeriodicalId":17267,"journal":{"name":"Journal of The Chemical Society-perkin Transactions 1","volume":"16 1","pages":"1139-1142"},"PeriodicalIF":0.0,"publicationDate":"2010-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76482319","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
K. A. Neidigh, M. Avery, J. Williamson, S. Bhattacharyya
A simple, mild and efficient procedure for obtaining N-methyl secondary amines from aldehydes and ketones is reported. Treatment of carbonyl compounds with methylamine hydrochloride, triethylamine and titanium(IV) isopropoxide, followed by in situ sodium borohydride reduction and straightforward aqueous work-up, affords clean products in good to excellent yields.
{"title":"Facile preparation of N-methyl secondary amines by titanium(IV) isopropoxide-mediated reductive amination of carbonyl compounds","authors":"K. A. Neidigh, M. Avery, J. Williamson, S. Bhattacharyya","doi":"10.1039/A803703E","DOIUrl":"https://doi.org/10.1039/A803703E","url":null,"abstract":"A simple, mild and efficient procedure for obtaining N-methyl secondary amines from aldehydes and ketones is reported. Treatment of carbonyl compounds with methylamine hydrochloride, triethylamine and titanium(IV) isopropoxide, followed by in situ sodium borohydride reduction and straightforward aqueous work-up, affords clean products in good to excellent yields.","PeriodicalId":17267,"journal":{"name":"Journal of The Chemical Society-perkin Transactions 1","volume":"24 1","pages":"2527-2532"},"PeriodicalIF":0.0,"publicationDate":"2010-06-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75115420","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Base-induced eliminations of the vinylogous β-hydroxysilanes 7, 9, 11 and 12 are stereospecifically syn, giving largely the trans,trans-diene 8 from 7 and 11, the cis,trans-diene 10 from 9, and the trans,cis-diene 13 from 12. When a cis double bond is produced, it is selectively placed adjacent to the carbon atom that originally carried the hydroxy group. E2′ Reactions with silyl as the electrofugal group and acetate as the nucleofugal group, initiated by fluoride ion, are not stereospecific, but can be highly stereoselective in favour of the trans,trans-diene 8 when the carbon substituent at the silicon-bearing end is a cyclohexyl group and the double bond is cis, and in favour of the trans,cis-diene 13 when the carbon substituent at the silicon-bearing end is a methyl group and the double bond is trans. Attempts to use the Peterson reactions to make o-quinodimethanes stereospecifically failed, with no evidence of 1,4-elimination from the alcohols 40 and 41. The corresponding E2′ reaction from the esters using fluoride ion on the acetates or formates 46 and 47 gave stereoselectively the E,E-quinodimethane 48.
{"title":"The stereochemistry of the vinylogous Peterson elimination","authors":"I. Fleming, I. Morgan, A. K. Sarkar","doi":"10.1039/A804090G","DOIUrl":"https://doi.org/10.1039/A804090G","url":null,"abstract":"Base-induced eliminations of the vinylogous β-hydroxysilanes 7, 9, 11 and 12 are stereospecifically syn, giving largely the trans,trans-diene 8 from 7 and 11, the cis,trans-diene 10 from 9, and the trans,cis-diene 13 from 12. When a cis double bond is produced, it is selectively placed adjacent to the carbon atom that originally carried the hydroxy group. E2′ Reactions with silyl as the electrofugal group and acetate as the nucleofugal group, initiated by fluoride ion, are not stereospecific, but can be highly stereoselective in favour of the trans,trans-diene 8 when the carbon substituent at the silicon-bearing end is a cyclohexyl group and the double bond is cis, and in favour of the trans,cis-diene 13 when the carbon substituent at the silicon-bearing end is a methyl group and the double bond is trans. Attempts to use the Peterson reactions to make o-quinodimethanes stereospecifically failed, with no evidence of 1,4-elimination from the alcohols 40 and 41. The corresponding E2′ reaction from the esters using fluoride ion on the acetates or formates 46 and 47 gave stereoselectively the E,E-quinodimethane 48.","PeriodicalId":17267,"journal":{"name":"Journal of The Chemical Society-perkin Transactions 1","volume":"138 1","pages":"2749-2764"},"PeriodicalIF":0.0,"publicationDate":"2010-06-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89357670","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Cycloadditions in synthesis","authors":"C. Dell","doi":"10.1039/A803583K","DOIUrl":"https://doi.org/10.1039/A803583K","url":null,"abstract":"","PeriodicalId":17267,"journal":{"name":"Journal of The Chemical Society-perkin Transactions 1","volume":"1 1","pages":"3873-3905"},"PeriodicalIF":0.0,"publicationDate":"2010-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74500437","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
(5S)-(5-tert-Butyldimethylsiloxymethyl)furan-2(5H)-one has been converted into cytosine 2′,3′-dideoxy-3′,5′-homocyclic monophosphate (and its 5-fluoro congener) together with an adenosine homocyclic monophosphate. These were designed as inhibitors of HIV reverse transcriptase although they did not possess such activity.
{"title":"The synthesis of novel 3′,5′-homocyclic nucleotides as potential anti-HIV agents","authors":"M. Drew, S. Gorsuch, Jayne H. M. Gould, J. Mann","doi":"10.1039/A900800D","DOIUrl":"https://doi.org/10.1039/A900800D","url":null,"abstract":"(5S)-(5-tert-Butyldimethylsiloxymethyl)furan-2(5H)-one has been converted into cytosine 2′,3′-dideoxy-3′,5′-homocyclic monophosphate (and its 5-fluoro congener) together with an adenosine homocyclic monophosphate. These were designed as inhibitors of HIV reverse transcriptase although they did not possess such activity.","PeriodicalId":17267,"journal":{"name":"Journal of The Chemical Society-perkin Transactions 1","volume":"26 1","pages":"969-978"},"PeriodicalIF":0.0,"publicationDate":"2010-06-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87230105","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Saturated and unsaturated lactones","authors":"I. Collins","doi":"10.1039/A808137I","DOIUrl":"https://doi.org/10.1039/A808137I","url":null,"abstract":"Covering: 1 November 1996 to 31 October 1997Previous review: Contemp. Org. Synth., 1997, 4, 281","PeriodicalId":17267,"journal":{"name":"Journal of The Chemical Society-perkin Transactions 1","volume":"38 1","pages":"1377-1396"},"PeriodicalIF":0.0,"publicationDate":"2010-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88651783","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Synthesis of aromatic heterocycles","authors":"T. L. Gilchrist","doi":"10.1039/A904578C","DOIUrl":"https://doi.org/10.1039/A904578C","url":null,"abstract":"Covering March 1999 to February 2001. Previous review: J. Chem. Soc., Perkin Trans. 1, 1999, 2849","PeriodicalId":17267,"journal":{"name":"Journal of The Chemical Society-perkin Transactions 1","volume":"7 1","pages":"615-628"},"PeriodicalIF":0.0,"publicationDate":"2010-06-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89142461","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Imines, enamines and oximes","authors":"Joseph P. Adams","doi":"10.1039/A808142E","DOIUrl":"https://doi.org/10.1039/A808142E","url":null,"abstract":"Covering: January 1997 to December 1998Continuing the coverage in Contemp. Org. Synth., 1997, 4, 517 \u0000p","PeriodicalId":17267,"journal":{"name":"Journal of The Chemical Society-perkin Transactions 1","volume":"1 1","pages":"125-139"},"PeriodicalIF":0.0,"publicationDate":"2010-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82930624","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A semisynthesis of 7-deoxypaclitaxel 4 is described, starting from taxine 6 – the most abundant naturally occurring taxane diterpene fraction. A key step in this transformation is a tandem reaction: stereoselective osmylation of cinnamic ester 14/intramolecularly assisted methanolysis of 16, which gives the key intermediate 5, along with the optically pure ester 17 – a precursor for the synthesis of the paclitaxel side-chain. In this way, the cinnamoyltaxicine 9 is converted into 7-deoxybaccatin III 25 in 11 steps, and in 15% overall yield.
本文描述了以天然存在的最丰富的紫杉烷二萜馏分-紫杉烷6为起始原料,半合成7-去氧紫杉醇4。这种转化的关键步骤是串联反应:肉桂酯14的立体选择性渗透化/分子内辅助甲醇分解16,得到关键中间体5,以及光学纯酯17,这是合成紫杉醇侧链的前体。通过这种方法,肉桂基的士素9通过11步转化为7-脱氧巴accatin III 25,总产率为15%。
{"title":"An efficient semisynthesis of 7-deoxypaclitaxel from taxine","authors":"R. Saicic, R. Matovic","doi":"10.1039/A907288H","DOIUrl":"https://doi.org/10.1039/A907288H","url":null,"abstract":"A semisynthesis of 7-deoxypaclitaxel 4 is described, starting from taxine 6 \u0000– the most abundant naturally occurring taxane diterpene fraction. A key step in this transformation is a tandem reaction: stereoselective osmylation of cinnamic ester 14/intramolecularly assisted methanolysis of 16, which gives the key intermediate 5, along with the optically pure ester 17 \u0000– a precursor for the synthesis of the paclitaxel side-chain. In this way, the cinnamoyltaxicine 9 is converted into 7-deoxybaccatin III 25 in 11 steps, and in 15% overall yield.","PeriodicalId":17267,"journal":{"name":"Journal of The Chemical Society-perkin Transactions 1","volume":"32 4 1","pages":"59-65"},"PeriodicalIF":0.0,"publicationDate":"2010-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90057865","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Carboxylic acids and esters","authors":"A. Franklin","doi":"10.1039/A808136K","DOIUrl":"https://doi.org/10.1039/A808136K","url":null,"abstract":"Covering: 1 August 1997 to 31 July 1998Previous review: J. Chem. Soc., Perkin Trans. 1, 1998, 2451","PeriodicalId":17267,"journal":{"name":"Journal of The Chemical Society-perkin Transactions 1","volume":"10 1","pages":"2451-2466"},"PeriodicalIF":0.0,"publicationDate":"2010-06-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86182781","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}