of the Month - Fluorous-Tagged
Chiral Phase-Transfer Catalyst
Recent work described modifying Maruoka's chiral phase-transfer catalyst by applying perfluoroalkyl ("fluorous") molecular tags to the catalyst which is used in asymmetric synthesis of α-amino acids. Fluorous phases and fluorous-tagged compounds - which can include reagents, intermediates, auxiliaries, etc. in addition to catalysts - can be easily and selectively separated by SPE, HPLC, or liquid-liquid extraction. In this case, the tagged catalyst was recovered for recycling. Fluorous compatibility with classical solution-phase reactions and facile single-method purification are key reasons that it's being applied in a wide variety of reactions - now including phase transfer catalysis. Shirakawa, S.; Tanaka, Y.; Maruoka, K.. Organic Letters, 2004, 6, 1429. For additional information about fluorous tagging, click on www.fluorous.com or contact Brett Bosley at firstname.lastname@example.org
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To improve route selection, process improvement, process development and overall reaction performance, contact Marc Halpern at tel +1 856-222-1146 or by E-mail.
Training - Plan
your training budget - Early
2005 in Chicago and Newark
The course "Practical Phase-Transfer Catalysis" will be conducted in Chicago and Newark in early 2005. Can't come to the course? Soon you will be able to purchase an audio CD set with manuals and license. "Practical Phase-Transfer Catalysis" can also be conducted at your company anytime (North America, Europe or Japan) as a private in-house course. More than 530 chemists, engineers and managers at nearly 100 companies have participated in this highly rated course from 1996 to 2004. Click here for details and agenda or contact us by E-mail or telephone (+1 856-222-1146) or fax (+1 856-222-1124).
patent attorney (United States) familiar with Phase-Transfer Catalysis,
organic chemistry and biochemistry. Contact Mannie Morgenstern by E-mail
or at telephone 818-788-5531 (California).
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Reaction of the Month - Michael
Addition to Perfluoropropene
Sometimes the added selectivity which PTC provides can have enormous impact on yield. This patent compares a Michael addition with and without tetrabutyl ammonium chloride under identical conditions and shows that PTC provides 93% yield while extensive destruction of starting material is observed without PTC (only 44% yield isolated with no recoverable starting material). Yamamoto, A. (Daikin Industries) US Patent 6,777,563 17-Aug-2004
Catalyst of the Month - 18-Crown-6
Outstanding phase-transfer catalyst for transferring and reacting a wide variety of inorganic salts with organic substrates (including both the anion and cation, e.g., KCN) from solid to organic phases. Often achieves high reactivity and sometimes induces unique selectivity (e.g., nucleophilicity vs basicity of t-butoxide!). Often easily separated by extraction into water.
Very expensive relative to other phase-transfer catalysts on a weight basis...though must estimate cost-benefit on a performance basis. Conflicting values for LD50 oral-rat have been published. Have your industrial hygienist evaluate before use.
Availability, Samples and Quotes from Competitors
Request samples and quotes from:
Dishman Pharmaceuticals & Chemicals, Eskay Industries (click on link)
Other Phase-Transfer Catalysts:
PTC Supplier Directory: choose from a dozen suppliers & 80 PT catalysts and ask for free samples & quotes.
Technology for Licensing
For details, contact Marc Halpern at tel +1 856-222-1146 or by E-mail.
Pharma - for PTC options during route selection, contact Marc Halpern by E-mail, website or telephone (+1 856-222-1146).
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performing any PTC reactions read this important message
Organic chemical reactions are inherently dangerous. Moreover, phase-transfer catalysis may provide rate and other enhancements which can intensify associated hazards. Under no circumstances should anyone perform any procedure on any scale based in whole or in part on any of the contents of this information provided here before thoroughly establishing safe operating procedures and performing a full and competent hazardous operations analysis with the participation of qualified technical personal trained in chemical, engineering, safety, industrial hygiene and environmental disciplines and sciences.
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PTC Tip of the Month #23 - August 2004
Copyright 2004 PTC Communications, Inc.
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