Siegfried E. Drewes

3.5k total citations · 1 hit paper
107 papers, 2.9k citations indexed

About

Siegfried E. Drewes is a scholar working on Organic Chemistry, Molecular Biology and Plant Science. According to data from OpenAlex, Siegfried E. Drewes has authored 107 papers receiving a total of 2.9k indexed citations (citations by other indexed papers that have themselves been cited), including 53 papers in Organic Chemistry, 49 papers in Molecular Biology and 21 papers in Plant Science. Recurrent topics in Siegfried E. Drewes's work include Synthetic Organic Chemistry Methods (19 papers), Natural product bioactivities and synthesis (14 papers) and Phytochemistry and Biological Activities (14 papers). Siegfried E. Drewes is often cited by papers focused on Synthetic Organic Chemistry Methods (19 papers), Natural product bioactivities and synthesis (14 papers) and Phytochemistry and Biological Activities (14 papers). Siegfried E. Drewes collaborates with scholars based in South Africa, United Kingdom and United States. Siegfried E. Drewes's co-authors include Gregory Roos, Neville D. Emslie, Marion Hörn, J. Van Staden, Fatima Khan, E.E. Elgorashi, Perry T. Kaye, Farouk Ameer, J.J.M. Meyer and Jacob George and has published in prestigious journals such as PLANT PHYSIOLOGY, The Journal of Organic Chemistry and Tetrahedron.

In The Last Decade

Siegfried E. Drewes

106 papers receiving 2.7k citations

Hit Papers

Synthetic potential of the tertiary-amine-catalysed react... 1988 2026 2000 2013 1988 200 400 600
What are hit papers?

Hit papers significantly outperform the citation benchmark for their cohort. A paper qualifies if it has ≥500 total citations, achieves ≥1.5× the top-1% citation threshold for papers in the same subfield and year (this is the minimum needed to enter the top 1%, not the average within it), or reaches the top citation threshold in at least one of its specific research topics.

  1. Synthetic potential of the tertiary-amine-catalysed reaction of activated vinyl carbanions with aldehydes
    1988 620 citations Siegfried E. Drewes, Gregory Roos profile →

Peers — A (Enhanced Table)

Peers by citation overlap · career bar shows stage (early→late) cites · hero ref

Name h Career Trend Papers Cites
Siegfried E. Drewes South Africa 27 1.8k 956 520 276 213 107 2.9k
Otmar Hofer Austria 31 1.2k 0.7× 1.2k 1.2× 795 1.5× 279 1.0× 407 1.9× 137 2.9k
Amarendra Patra India 27 896 0.5× 656 0.7× 404 0.8× 367 1.3× 162 0.8× 121 2.0k
Leslie Crombie United Kingdom 26 1.4k 0.8× 1.3k 1.4× 888 1.7× 600 2.2× 154 0.7× 277 3.6k
Giuliano Delle Monache Italy 31 1.0k 0.6× 1.6k 1.6× 858 1.6× 515 1.9× 228 1.1× 147 2.9k
Tadashi Masamune Japan 28 1.2k 0.7× 967 1.0× 576 1.1× 257 0.9× 88 0.4× 202 2.7k
Bruno Danieli Italy 31 1.6k 0.9× 1.7k 1.8× 570 1.1× 255 0.9× 520 2.4× 195 3.3k
Johannes Reisch Germany 21 1.2k 0.7× 848 0.9× 682 1.3× 390 1.4× 141 0.7× 308 2.3k
Stewart McLean Canada 27 952 0.5× 1.3k 1.3× 679 1.3× 558 2.0× 350 1.6× 177 2.9k
Mitsuaki Kodama Japan 29 985 0.6× 1.2k 1.2× 614 1.2× 399 1.4× 153 0.7× 126 2.5k
David Dı́ez Spain 26 1.8k 1.0× 1.0k 1.1× 225 0.4× 329 1.2× 209 1.0× 206 2.8k

Countries citing papers authored by Siegfried E. Drewes

Since Specialization
Citations

This map shows the geographic impact of Siegfried E. Drewes's research. It shows the number of citations coming from papers published by authors working in each country. You can also color the map by specialization and compare the number of citations received by Siegfried E. Drewes with the expected number of citations based on a country's size and research output (numbers larger than one mean the country cites Siegfried E. Drewes more than expected).

Fields of papers citing papers by Siegfried E. Drewes

Since Specialization
Physical SciencesHealth SciencesLife SciencesSocial Sciences

This network shows the impact of papers produced by Siegfried E. Drewes. Nodes represent research fields, and links connect fields that are likely to share authors. Colored nodes show fields that tend to cite the papers produced by Siegfried E. Drewes. The network helps show where Siegfried E. Drewes may publish in the future.

Co-authorship network of co-authors of Siegfried E. Drewes

This figure shows the co-authorship network connecting the top 25 collaborators of Siegfried E. Drewes. A scholar is included among the top collaborators of Siegfried E. Drewes based on the total number of citations received by their joint publications. Widths of edges represent the number of papers authors have co-authored together. Node borders signify the number of papers an author published with Siegfried E. Drewes. Siegfried E. Drewes is excluded from the visualization to improve readability, since they are connected to all nodes in the network.

All Works

20 of 20 papers shown
1.
Drewes, Siegfried E.. (2012). Natural products research in South Africa : 1890 - 2010 : review article. South African Journal of Science. 108. 1–8. 1 indexed citations
2.
Drewes, Siegfried E.. (2012). Natural products research in South Africa: 1890–2010. South African Journal of Science. 108(5/6). 12 indexed citations
3.
Drewes, Siegfried E. & Sandy van Vuuren. (2008). Antimicrobial acylphloroglucinols and dibenzyloxy flavonoids from flowers of Helichrysum gymnocomum. Phytochemistry. 69(8). 1745–1749. 46 indexed citations
4.
Ojewole, John A. O. & Siegfried E. Drewes. (2007). Hypoglycaemic effect of Eriosema kraussianum N. E. Br. [Fabaceae] rootstock hydro-alcohol extract in rats. Journal of Natural Medicines. 61(3). 244–250. 4 indexed citations
5.
Crouch, Neil R., et al.. (2006). Bufadienolides from bulbs of Urginea lydenburgensis (Hyacinthaceae: Urgineoideae). Phytochemistry. 67(19). 2140–2145. 11 indexed citations
6.
Ojewole, John A. O., Siegfried E. Drewes, & Fatima Khan. (2006). Vasodilatory and hypoglycaemic effects of two pyrano-isoflavone extractives from Eriosema kraussianum N. E. Br. [Fabaceae] rootstock in experimental rat models. Phytochemistry. 67(6). 610–617. 27 indexed citations
7.
Elgorashi, E.E., Sarel F. Malan, Siegfried E. Drewes, et al.. (2005). Anti-inflammatory activity and QSAR studies of compounds isolated from Hyacinthaceae species and Tachiadenus longiflorus Griseb. (Gentianaceae). Bioorganic & Medicinal Chemistry. 13(7). 2561–2568. 41 indexed citations
8.
Mulholland, Dulcie A. & Siegfried E. Drewes. (2004). Global phytochemistry: indigenous medicinal chemistry on track in southern Africa. Phytochemistry. 65(7). 769–782. 23 indexed citations
9.
Drewes, Siegfried E., Jacob George, & Fatima Khan. (2003). Recent findings on natural products with erectile-dysfunction activity. Phytochemistry. 62(7). 1019–1025. 105 indexed citations
10.
Elgorashi, E.E., Siegfried E. Drewes, & J. Van Staden. (2002). Organ-to-organ and seasonal variation in alkaloids from Crinum macowanii. Fitoterapia. 73(6). 490–495. 33 indexed citations
11.
Drewes, Siegfried E., et al.. (2002). Pyrano-isoflavones with erectile-dysfunction activity from Eriosema kraussianum. Phytochemistry. 59(7). 739–747. 44 indexed citations
12.
Elgorashi, E.E., Siegfried E. Drewes, & J. Van Staden. (2001). Alkaloids from Crinum moorei. Phytochemistry. 56(6). 637–640. 34 indexed citations
13.
Hörn, Marion, et al.. (2001). Transformation of naturally-occurring 1,9-trans-9,5-cis sweroside to all trans sweroside during acetylation of sweroside aglycone. Phytochemistry. 57(1). 51–56. 25 indexed citations
14.
Elgorashi, E.E., Siegfried E. Drewes, & J. Van Staden. (2001). Alkaloids from Crinum macowanii. Biochemical Systematics and Ecology. 29(7). 749–750. 18 indexed citations
15.
Zschocke, S., J. Van Staden, Rudolf Bauer, et al.. (2000). Stereostructure and anti-inflammatory activity of three diastereomers of ocobullenone from Ocotea bullata. Phytochemistry. 54(6). 591–595. 28 indexed citations
16.
Drewes, Siegfried E., et al.. (1998). Absolute configurations of all four stereoisomers of cryptocaryalactone and deacetyl cryptocaryalactone. Phytochemistry. 49(6). 1683–1687. 18 indexed citations
17.
Drewes, Siegfried E., et al.. (1988). Synthesis of 3-Hydroxy-2-Methylene Carbonyl Compounds - Effect of Catalyst and Substrate on Reaction Rate. Synthetic Communications. 18(13). 1565–1572. 48 indexed citations
18.
Staden, J. Van & Siegfried E. Drewes. (1984). Structural Changes of Zeatin During Acid Hydrolysis. Journal of Plant Physiology. 115(2). 137–142. 3 indexed citations
19.
Staden, J. Van, et al.. (1983). Cytokinins in the Leaves of Ginkgo biloba. PLANT PHYSIOLOGY. 73(2). 223–227. 8 indexed citations
20.
Sutton, Donald A., et al.. (1976). Preparation of a Crystalline A1-(2-Nitro-4-trimethylammoniophenyl) Derivative of Bovine Insulin. Hoppe-Seyler´s Zeitschrift für physiologische Chemie. 357(2). 971–976. 7 indexed citations

Rankless uses publication and citation data sourced from OpenAlex, an open and comprehensive bibliographic database. While OpenAlex provides broad and valuable coverage of the global research landscape, it—like all bibliographic datasets—has inherent limitations. These include incomplete records, variations in author disambiguation, differences in journal indexing, and delays in data updates. As a result, some metrics and network relationships displayed in Rankless may not fully capture the entirety of a scholar's output or impact.

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