Studies on the synthesis and uses of acylaziridines derived from enones have continued. These aziridines are prepared from simple primary amines anda suitable enone. Simple reaction of these aziridines with mild acids produces enones with alternative substitution. The aziridine group is thus a useful protecting group. We hope that these readily available compounds will allow us to resolve substituted cyclohexenones, to produce optically active starting materials for synthesis, using readily available optically pure amines.
Christopher David Maycock
Phone (+351) 21446 9775
Most active pharmaceuticals are small synthetic molecules which have been and will continue to be the mainstay of the fight against a wide range of diseases and syndromes. The construction of multifunctional molecules requires an arsenal of reagents and strategies in order to overcome the problems arising. On top of the simple chemistry we have the added sophistication of stereochemistry which increases the problem exponentially. Efficiency, sustainability and reduced dependence upon petroleum products are also a desirable options for the synthesis of small molecules in an isomerically pure form. Controlling all of these parameters is of fundamental importance for modern organic synthesis.
Natural product syntheses are a great challenge since the product gross structure and stereochemistry are rigorously defined. Any synthesis is a test of the viability of the strategy and of the compatibility of the reagents. The organic synthesis group is dedicated to the synthesis of compounds which have a relatively complex three dimensional structure and which may not necessarily be related to the gross structure. Recently we have found that simple conjugate additions using nitrogen nucleophiles do not produce the product predicted by steric hindrance and that some other electronic effect is involved. Further more the aziridines formed in these reaction are able to invert the stereochemical outcome of further reactions in conformationally restricted compounds. This has led us to the resolution of an important intermediate and stereocontrolled synthesis of some optically pure natural products. We are applying this technology to the synthesis of others. The reactivity of some aziridines which are strained compounds has also been the subject of a study and the preparation of variously alfa-substituted cyclic enones has been possible.
Quantum dots are nano-sized spheres of a semiconducting material which fluoresce over a wide range of irradiation frequency. They can be produced in various sizes and depending on their size emmit light of different colours. Lipophilic or hydrophilic QDs can be prepared using suitable ligands which are loosely bound to the surface of the spheres. Bioconjugates QDs can be prepared and are able to enter cells, for example, and their presence observed using a fluorescence microscope. We have prepared stable QDs having different terminations on the ligand molecules and these include sugar molecules which are able to stabilise proteins and also ones which will be able to recognise binding sites on cell surfaces and hopefully be transfected through the cell wall. Functionalisation with antibodies for the study of parasitic diseases is also underway. Magnetic nanoparticles are also able to enter biological systems and we are planning to effectively selectively magnetise living organisms for magnetic detection.
- Sofia Miguel, PhD student (in co-supervision)
Paula Rodrigues, PhD Student
Mário Soromenho, Graduate
Rita Lopes, Graduate
- A First Synthesis of (-)-Asperpentyn and Efficient Syntheses of (+)-Harveynone, (+)-Epoformin and (-)-Theobroxide. M.T. Barros, C.D. Maycock, M.R. Ventura, Chem. Eur. J. 2000, 6, 3991
- Aziridines as a Protecting and Directing Group. Stereoselective Synthesis of (+)-Bromoxone, Barros, M. T.; Maycock, C. D.; Ventura, M. R., Org. Lett. 2003, 5, 4321
- Highly Stereoselective Aldol Reaction for the Synthesis of gama-Lactones Starting from Tartaric Acid, Barros, M. T.; Burke, A. J.; Lou, J.-D.; Maycock, C. D.; Wahnon, J. R.; J. Org. Chem. 2004, 108, 2155-2166
- Stereoselective Alkylation of Tartrate Derivatives. A Concise Route to (+)-Piscidic Acid and Natural Analogues, Burke, A. J.; Maycock, C. D.; Ventura, M. R., Org. Biomol. Chem. 2006, 4, 2361.
- M. Teresa Barros, M. Adilia Januario Charmier, Christopher D. Maycock, Thierry Michaud Synthesis of g-lactones by desymmetrization. A synthesis of ( )-muricatacin, Tetrahedron, 2009, 65, 396-399
For further information please visit the laboratory's website
O Laboratório de Síntese Orgânica estuda a síntese de moléculas que têm ou podem ter interesse biológico, estereosselectivamente, portanto numa forma estereoquímicamente pura. Tentamos descobrir novas vias de síntese para moléculas estereoquímicamente complexas e estratégias
para a síntese efi ciente destas moléculas. Também colaboramos com grupos de química, biologia e bioquímica na síntese de moléculas que não existem no mercado ou que são completamente novas. Uma faceta importante é a nossa ligação com a indústria farmacêutica na procura de novas vias de síntese de medicamentos de conhecida actividade, a transferência de tecnologia e ajuda logística.