The Pharmaceutical Chemistry Group

The Group focuses on the design and synthesis of biologically active molecules which could prove beneficial in human therapy. Specifically the current research projects involve the design and synthesis of anticancer, analgesic, antiarrhythmic, antiparasitic and CNS acting agents. An integral part of our activities in medicinal chemistry is the development of novel synthetic methodologies.

Members

Research Staff

Dr. Theodora Calogeropoulou (Senior Researcher)
Dr. Maria Koufaki (Senior Researcher)
Dr. Demetris Papahatjis (Senior Researcher)
Dr. Evangelos Kalatzis (Research Director in Emeritus)

Postdoctoral Fellows

Dr. Anastasia Detsi

M.Sc. and Ph.D. Students

Theano Fotopoulou (MSc Student)
Marianthi Gianni (MSc. Student)
Aristotelis Menissiou (MSc. Student)
Nicolaos Avlonitis, MSc, (PhD. Student)
Kalliopi Georgikopoulou, MSc, (PhD. Student)
Christina Kiziridi, MSc., (PhD. Student)
Eftyhia Koini, MSc., (PhD. Student)
Victoria Nahmia, MSc., (PhD. Student)
George Naxakis, MSc., (PhD. Student)
Elissavet Theodorou, MSc., (Ph.D. Student

Technical Staff

Stamatina Kopsida (Technical Assistant)
Ekaterini Nakou (Technical Assistant)

Current Projects

Synthesis of novel Antiarrhythmics
This project is a combined strategy aimed at exploiting the use of new effective drugs against ischemia or reperfusion arrhythmias as well as against free radical damage of the reperfused myocardium. These compounds could be also employed for the long term protection after acute myocardial infarction.
Our research involves the design and synthesis of benzopyran or 1,4-benzoxazine derivatives decorated with class I or class III antiarrhythmic pharmacophores.

Chroman/1,2-dithiolane and chroman/catechol hybrids active against oxidative stress induced cellular damage
Lipoic acid (1,2-dithiolane-3-pentanoic acid) has been shown to be beneficial in a number of oxidative stress models such as ischemia-reperfusion injury, diabetes, inflammation, neurodegeneration and radiation injury.
Compounds bearing 3,4-dihydroxyphenyl (catechol) moieties possess a wide spectrum of biological activities, which is related to their capacity to transfer electrons, to chelate ferrous ions and to scavenge ROS.
The aim of this project is the design and synthesis of chroman analogues substituted at position 2, 4 or 5 by 1,2-dithiolane or catechol moieties in order to achieve improved cytoprotection against toxicity due to oxidative stress as implicated in several neurodegenerative diseases, such as Alzheimer's disease and Parkinson's disease.

Biologically-Active Ether Phospholipids
Lipids are central to the regulation and control of cellular function and to disease, and lipidomics is beginning to make signifi¬cant contri¬butions to our understanding of cellular and pathophysiological processes. Alkyllysophospholipid analogues have recently received much attention due to their antineoplastic, immunomodulatory and antiprotozoal properties. This is in line with our objective of developing pharmaceutical research with a strong component of lipid chemistry.
We have been involved in bioactive ether phospholipid (EP) research and we have employed EPs as drug delivery systems and as agents against cancer and protozoal diseases. Main emphasis has been given in the design and synthesis of ring-substituted EPs.

Steroid analogues as GABAA modulators or neuroprotective agents
Neurosteroids are synthesized in the central and peripheral nervous system, and have been implicated in neuroprotection, cognitive and psychiatric dysfunctions, premenstrual syndrome, and GABAA receptor plasticity. GABAA agonistic steroids, have been shown to be potent anticonvulsants, anxiolytics and antistress agents and to possess sedative, hypnotic and anesthetic activities. Our research activities in this area are two-fold and encompass the design and synthesis of steroid analogues in order to probe the structural and stereoelectronic requirements for specific GABAA agonistic activity or neuroprotective activity.

Molecular probes for cannabinoid receptors
The discovery and cloning of CB1 and CB2, the two known Gi/o protein-coupled cannabinoid receptors, as well as the isolation and characterization of two families of endogenous cannabinergic ligands represented by arachidonoylethanol¬amide (anandamide) and 2-arachidonoylglycerol (2-AG), have opened new hori¬zons in this newly discovered ?eld of biology. Furthermore, a considerable number of cannabinoid analogs belonging to structurally diverse classes of compounds have been synthesized and tested, thus providing substantial information on the structural requirements for cannabinoid receptor recognition and activation. Ex¬periments with site-directed mutated receptors and computer modeling studies have suggested that these diverse classes of ligands may interact with the recep¬tors through different binding motifs. The information about the exact binding site may be obtained with the help of suitably designed molecular probes. Our research activities are directed towards the design and synthesis of new therapeutically useful cannabinoid analogues for pain and central nervous system diseases.

Development of Tissue-Specific Antiestrogens
Breast cancer is the most frequent cancer and a major cause of death among women in western societies. Adjuvant tamoxifen is the cornerstone of breast cancer therapy as well as a breast cancer preventive in high risk women. However, it has high levels of life-threatening side effects such as endometrial cancer and hepatocellular carcinoma accompanied with the development of drug resistance. Raloxifene, a third generation antiestrogen initially introduced for the treatment of osteoporosis, is currently under scrutiny for breast cancer prevention and treatment. Studies comparing the effectiveness of these two agents, suggest that effective tissue-specific antiestrogens are yet to be developed.
Accumulated evidence indicated that, within the raloxifene molecule, the location and structure of the side chain plays a pivotal role in determining selective estrogen action. Structural variations within this pharmacophore can result in large changes in its tissue selectivity profile. To that end, we decided to examine the effect of cycloalkyl substitution between the amine terminus and the benzothiophene core of raloxifene.

Development of Synthetic Methodology

. Solid phase organic synthesis and high energy techniques
We are initiating a 4-year Marie Curie Transfer of Knowledge project, in collaboration with the Organic and Organometallic Chemistry Group, ''Sopholides'', i.e. Solid-Phase Phospholipid and Dendrimer Synthesis in order to enhance our research capability in the area of modern synthetic methods such as solid phase organic synthesis and the use of high energy techniques.

. Simple and efficient halogenation of oxygenated aromatic substrates
Halogenated compounds are of interest as intermediates for the synthesis of biologically active molecules. We have developed a new, simple and mild method for the introduction of halogen substituents to oxygenated aromatic rings. The reaction is regioselective and the products are obtained in high yields without concomitant oxidative halogenation.

. Synthesis of 4-hydroxytamoxifen analogues
The synthesis of (Z)-4-hydroxytamoxifen and (Z)-2-{4-[1-(p-hydroxyphenyl)-2-phenyl]-1-butenyl}phenoxyacetic acid in pure stereochemical form was accomplished using a McMurry reaction as the key step. The methodology proceeds without E, Z isomerisation, employs a very mild final debenzylation step compatible with a large array of functional groups and can be applied to the generation of a variety of 4-hydroxytamoxifen analogues.

. Introduction of fluorine probes into biologically active compounds by a novel desulfurative fluorination method
The introduction of fluorine probes into biologically active substances strongly modifies the physical, chemical and biological properties. Desulfurative fluorination, one of the useful methods in forming carbon-fluorine bonds by the cleavage of carbon-sulfur bonds, employs a combination of an oxidative reagent and HF or HF-base complex. We have developed new synthetic methodology and synthetic protocols for the introduction of gem difluorides at strategically chosen positions of the cannabinoid and raloxifene structure.

. New synthetic technology enabling the synthesis of conformationally constrained bioactive molecules
In the course of our cannabinoid program we were faced with the problem of introducing cycloalkane rings at the benzylic position of the side chain. This has motivated us to develop a general method for substituting activated aryl methylenes with cycloalkyl groups of varying ring size. The ready availability of compounds with restricted conformations through carbocyclic annelation should provide biologically active molecules of value in medicinal chemistry. Efforts to provide such systems are in progress in our laboratories.

Current Collaborations

Prof. D. Galaris, Medical School, University of Ioannina Greece
Ass. Prof. P. Papazafiri, Department of Biology, University of Athens
Dr. M. N. Alexis, IBRB/NHRF
Prof. A. Gravanis, Medical School, University of Crete, Greece
Ass. Prof. E. Scoulica, Medical School, University of Crete, Greece
Prof. N. Hadjichristides, Chemistry Department, University of Athens, Greece
Asc. Prof. V. Roussis, Pharmacy Department, University of Athens, Greece
Asc. Prof. A. Tsotinis, Pharmacy Department, University of Athens, Greece
Asc. Prof. E. Iliodromitis, Medical School, University of Athens, Greece
Dr J. Andreadou, Pharmacy Department, University of Athens, Greece
Prof. C. Spyraki, Medical School, University of Athens, Greece
Asc. Prof. K. Thermos, Medical School, University of Crete, Greece
Ass. Prof. G. Panagis, School of Social Sciences, University of Crete, Greece
Lecturer K. Antoniou, Medical School, University of Ioannina Greece
Prof. A Varro, Department of Pharmacology, University of Szeged, Hungary
Prof. A. Makriyannis, Northeastern University, Boston, USA.
Dr S. Nikas, Northeastern University, Boston, USA.
Dr G. Maksay, Chem. Res. Cent., Hung. Academy of Sciences, Budapest, Hungary
Prof. G. Campiani, University of Sienna, Italy
Prof. M. Bradley, Chemistry Department, University of Edinburgh, UK
Prof. D. Walton, Chemistry Department, University of Coventry, UK
Prof. A. Loupy, Universite Paris-Sud, France.

Funded Programmes

Current and recently completed projects

. Excellence in the Research Institutes supervised by the Greek General Secretariat for Research and Technology EPAN 3.3.1. (2002-2005). "Novel strategies against neurodegeneration.'' Carried out jointly with the Organic and Organometallic Chemistry and Computational Chemistry groups.

. Bilateral Collaboration of Greece-Hungary (2002 - 2004) "Neuroactive steroids and ionotropic neurotransmitter receptors.''
Coordinator: Dr. T. Calogeropoulou

. GSRT programme Location and use of research results by the creation of new enterprises (Spin-off, 2003-05) "New ether phospholipids as ultrasound contrast agents''
Scientists in charge: Dr. T. Calogeropoulou, Dr. M. Koufaki

. GSRT programme Location and use of research results by the creation of new enterprises (Spin-off, 2003-05) "Cannabimimetic compounds with therapeutic applications''
Scientist in charge: Dr. D. Papahatjis

. GSRT programme Location and use of research results by the creation of new enterprises (Spin-off, 2003-05) "Tissue-specific antiestrogens''
Scientist in charge: Dr. D. Papahatjis

. Univ. Connencticut PSA No 4505 (2004-2005) '' Novel Antioxidants and Bioactive ether phospholipids''
Scientists in charge: Dr. M. Koufaki, Dr. T. Calogeropoulou

. PENED 2001 GSRT (2002-2006). Investigation of the mechanisms of action of neuroprotective neurosteroids. Development of new compounds with high neuroprotective and low estrogenic or androgenic activity.
Scientist in charge: Dr. T. Calogeropoulou

. Operational Programme for Competitiveness, GSRT YB/39(2004-2007). Therapeutic Interventions Against Protozoan Infections.
Coordinator: Dr. T. Calogeropoulou

. Operational Programme for Competitiveness, GSRT YB/60 (2003-2006). "Synthesis of novel cannabinoid analogues with potential analgesic, psychokinetic and psychotropic action devoid of withdrawal effects.''
Scientist in charge: Dr. D. Papahatjis

. Marie Curie Transfer of Knowledge Programme - MTKD-CT-2004-014399.(2005-2009) ''Solid-phase phospholipid and dendrimer synthesis'', Carried out jointly with the Organic and Organometallic Chemistry groups.
Coordinator: Dr. T. Calogeropoulou

. Bilateral Collaboration of Greece-Hungary (2003-2006). "Synthesis of novel antiarrhythmics and study of their electrophysiological effects''
Coordinator: Dr. M. Koufaki

PUBLICATIONS 2000-TO DATE

Faust R., Garratt P.J., Jones R., Yeh L.-K., Tsotinis A., Panoussopoulou M., Calogeropoulou T., Teh M.-T. and Sugden D.
"Mapping the melatonin receptor. 6. Melatonin agonists and antagonists
derived from 6H-isoindolo[2,1-a]indoles, 5,6-dihydroindolo[2,1-a]isoquinolines and 6,7-dihydro-5H-benzo[c]azepino[1,2-a]indoles.''
J. Med. Chem. 2000, 43(6), 1050-1061.

Varvaresou A, Kriton I, Filippatos E., Souli C., Calogeropoulou T., Ioannidou I., Kourounakis A., Pannecouque C., Witvrouw M., Padalko E., Neyts J., De Clercq E., Tsotinis A.
"Synthesis, Antiretroviral and Antioxidant Evaluation of a Series of New Benzo[b]furan Derivatives.''
Arzneim.-Forsch./Drug Res. 2001, 51(I), 156.

Carbonenelle D., Jacquot C., Lanco X., Le Dez G., Tomasoni C., Briand G., Tsotinis A., Calogeropoulou T., Roussakis C.
''Up-regulation of a novel mRNA (NY-CO-1) involved in the (1-(2-alkoxy-5-carboxyl)-a-β-unsaturated ketone (VT1)-induced proliferation arrest of a Non-Small Cell lung carcinoma cell line (NSCLC-N6)''
International J. Cancer 2001, 92 (3), 388-397.

Mavromoustakos T., Calogeropoulou T., Koufaki M., Kolocouris A., Demetzos K., Meng Z., Makriyannis A., Balzarini J. and De Clercq E.
"Ether phospholipid-AZT conjugates possessing anti-HIV and anti-tumor cell activity. Synthesis, conformational analysis and study of their thermal effects on membrane bilayers''
J. Med. Chem 2001, 44(11), 1702-1709.

Koufaki M., Calogeropoulou T., Detsi A., Roditis A., Kourounakis A., Papazafiri P., Tsiakitzis K., Gaitanaki C., Beis I., Kourounakis P.
''Novel potent inhibitors of lipid peroxidation with protective effects against reperfusion arrhythmias.''
J. Med. Chem. 2001, 44, 4300-4303.

Papahatjis P. Demetris, Nikas Spyros, Tsotinis Andrew, Vlachou Margarita and Makriyannis Alexandros.
"A New Ring-Forming Methodology for the Synthesis of Conformationally Constrained Bioactive Molecules''
Chemistry Letters 2001, 3, 192.

Mavromoustakos T., Papahatjis D.P., Laggner P..
"Differential membrane fluidization by active and inactive cannabinoid analogs''
Biochimica et Biophysica Acta 2001, 1511, 183.

Detsi A., Koufaki M., Calogeropoulou T.
''Synthesis of (Z)-4-hydroxytamoxifen and (Z)-2-(4-[1-(p-hydroxyphenyl)-2-phenyl]-1-butenyl)phenoxyacetic acid.''
J. Org. Chem. 2002, 67, 4608-4611.

Papahatjis P. Demetris, Nikas P. Spyros, Andreou Thanos and Makriyannis Alexandros.
''Novel 1',1'-Chain Substituted ?8-Tetrahydrocannabinols''
Biorganic and Medicinal Chemistry Letters. 2002, 3583.

Avlonitis N., Lekka E., Detsi A., Koufaki M., Calogeropoulou T., Skoulica E., Siapi E., Kyrikou I., Mavromoustakos T., Tsotinis A., Golic Grdadolnik S., Makriyannis A. '' Antileishmanial Ring-Substituted Ether Phospholipids''
J. Med. Chem. 2003, 46, 755-767.

Koufaki, M.; Calogeropoulou, T.; Rekka, E.; Chryselis, M.; Papazafiri, P.; Gaitanaki, C.; Makriyannis, A. ''Bifunctional Agents for Reperfusion Arrhythmias. Novel Hybrid Vitamin E/Class I Antiarrhythmics.''
Bioorg. Med. Chem. 2003, 11, 5209-5219.

Papahatjis P. Demetris, Nikas P. Spyros, Kourouli Therapia, Chari Ravi, Xu Wei, Pertwee G. Roger and Makriyannis Alexandros.
''Pharmacophoric Requirements for Cannabinoid Side Chains. 3: Probing the Cannabinoid Receptor subsite at C1΄''
J. Med. Chem. 2003, 46, 3221.

Koufaki M., Detsi A., Theodorou E., Kiziridi C., Calogeropoulou T., Vassilopoulos A.,. Kourounakis A., Rekka E., Kourounakis P., Gaitanaki C., Papazafiri P. Synthesis of Chroman Analogues of Lipoic Acid and Evaluation of their Activity against Reperfusion Arrhythmias.
Bioorg. Med. Chem. 2004, 12, 4835.

Spyros P. Nikas, Jolanta Grzybovska, Demetris P. Papahatjis, Avgui Charalambous, Ali R. Banijamali, Ravi Chari, Pusheng Fan, Therapia Kourouli, Sonyuan Lin, Albert J. Nitowski, Gilbert Marciniak, Yan Guo, Xiuyan Li, Chia-Lin J. Wang and Alexandros Makriyannis.
''The Role of Halogen Substitution in Classical Cannabinoids. A CB1 Pharmacophore Model. ''
AAPS, Journal. 6(4): Article 30 2004.

Papazafiri P., Avlonitis N., Angelou P., Calogeropoulou T., Koufaki M., Scoulica E., Fragiadaki I. "Structure-activity relationships of antineoplastic ring-substituted ether phospholipid derivatives'' Cancer Chemother. Pharmacol. 2005, (in press. DOI: 10.1007/s00280-004-0935-6)

Souli C., Avlonitis N., Calogeropoulou T, Tsotinis A., Maksay G., Biro T, Politi A., Mavromoustakos T., Makriyannis A., Reis H., Papadopoulos M.. "Novel 17β-substituted conformationally constrained neurosteroids that modulate GABAA receptors'' J. Med. Chem. 2005, (accepted for publication).

Antoniou K, Galanopoulos A, Vlachou S, Nahmias V, Thermos, K, Panagis G, Daifoti Z, Marselos M., Papahatjis D, and Spyraki C.
''Preclinical behavioral evaluation of a novel cannabinoid analogue''
Rev. Clinical Pharmacology and Pharmacokinetics, 23, 26 (2005).

PATENTS
GR-1003103
"1-(2-ALKOXY-5-CARBOXYPHENYL)-A,Β-UNSATURATED KETONES. THEIR PREPARATION AND APPLICATION IN THERAPEUTICS.''
Inventors: A. Tsotinis, T. Calogeropoulou, C. Roussakis, V. Roussis

WO 9954278
''1-(2-Alkoxy-5-carboxyphenyl)-a,β-unsaturated ketones. Their preparation and application in therapeutics.''
Inventors: A. Tsotinis, T. Calogeropoulou, C. Roussakis, V. Roussis
Applicant: CORNEAL Industries

GR 1003861
"GABAA MODULATING NEUROSTEROIDS''
Inventors: Theodora Calogeropoulou, Charikleia Souli, Andrew Tsotinis, Alexandros Makriyannis

WO 02053577
GABAA MODULATING NEUROSTEROIDS
Applicant: ELPEN S.A.
Inventors: Theodora Calogeropoulou, Charikleia Souli, Andrew Tsotinis, Alexandros Makriyannis

GR 1003725
''Bifunctional agents possessing antioxidant and antiarrhythmic activity''
Applicants and Inventors: Maria Koufaki, Theodora Calogeropoulou, Alexandros Makriyannis

WO 0204438, US2004259763, CA2415523, EP1301504
''Bifunctional agents possessing antioxidant and antiarrhythmic activity''
Applicant: UNI-PHARMA S.A.
Inventors: Maria Koufaki, Theodora Calogeropoulou, Alexandros Makriyannis

WO 2004041167, US2003/34225
''Antiprotozoal ring-substituted phospholipids''
Inventors: Theodora Calogeropoulou, Maria Koufaki, Nikolaos Avlonitis, Alexandros Makriyannis

GR20050100100 (2/3/05)
«Ultrasound contrast agents containing anticancer ether phospholipids''
Inventors: Theodora Calogeropoulou, Maria Koufaki

REVIEWS
Calogeropoulou Τ., Detsi Α., Lekkas Ε, Koufaki Μ. Strategies in the design of prodrugs of anti HIV agents in '' Therapeutic strategies against HIV infection'' Guest Editor M. Koufaki. Current Topics in Medicinal Chemistry, 2003, 3 (13), 1467