(-)-BETA-PINENE AS CHIRAL PROMOTER - STEREOSPECIFIC ACCESS TO (-)-GAMMA-AMINO-BETA(R)-HYDROXYBUTYRIC ACID (GABOB) AND (R)-CARNITINE.2

The stereochemical correlation between the ene adducts 2 and 4a and their products of alkaline hydrolysis is reported. Starting from 2, by using a degradative sequence, a stereocontrolled approach to \u3b3-amino-\u3b2(R)-hydroxybutyric acid (GABOB) 8f and (R)-carnitine hydrochloride 8g is described

Application of the Pd-catalyzed heteroarylation to the synthesis of 5-(indol-2 '-yl)pyridin-2-one and 5-(indol-2 '-yl)pyran-2-one

The synthesis of 5-(indol-2'-yl)pyridin-2-ones and 5-(indol-2'-yl)pyran-2-one by Pd-catalyzed reactions is described. The best results are obtained using 2-indolylstannanes or 2-indolylzinc halides to be coupled with 5-bromopyridin-2-ones or 5-bromopyran-2-one in the presence of Pd(PPh3)(4) catalyst. Other Pd-catalyzed reactions are discussed. (C) 1998 Elsevier Science Ltd. All rights reserved

Photochemical isomerization of colchicine and thiocolchicine

The photochemical reactivity of colchicine and thiocolchicine is described. Although the irradiation of colchicine gave a well-known transposition reaction to beta- and gamma-lumicolchicines, thiocolchicine did not react. Femtosecond transient spectroscopy of colchicine showed a strong band with maximum at 510 nm appearing at tau = 0. It disappeared within few hundred femtoseconds, leaving a broad structureless band with a maximum around 470 urn. A second band is observed around 410 nm. The analysis in time showed that the 510-nm component appeared instantaneously and decayed following a biexponential low with time constants of 300 +/- 100 fs and 40 ps. The kinetics at 420 nm has a measurable rise lime of 300 +/- 150 fs. Quantum mechanical calculations on colchicine showed that this absorption is due to a S-1 --> S-11 transition. In thiocolchicine, the instantaneous formation of a structure with maxima out of the investigated spectral region was observed. A strong absorption around 650 nm indicated the presence of a band with a maximum at longer wavelengths (> 700 nm) and a peak around 380 nm, which partially coincides with the ground-state absorption and therefore strongly affected absorption around 650 nm and its rapid (similar to500 fs) decay by its bleaching. The instantaneous formation of an absorption was observed. At shorter wavelengths (400 nm), the t decay was fitted with a biexponential curve with the first time constant of about 80 ps. The second part of,the decay had a very long tail up to 500 ps. Transient spectroscopy and configuration interaction calculations are in agreement with a mechanism involving a disrotatory cyclization of colchicine in its first excited singlet state. The lack of reactivity observed in thiocolchicine was explained by considering the presence of efficient ISC to the triplet state

Photochemical isomerization of colchicine and thiocolchicine

The photochemical reactivity of colchicine and thiocolchicine is described. Although the irradiation of colchicine gave a well-known transposition reaction to beta- and gamma-lumicolchicines, thiocolchicine did not react. Femtosecond transient spectroscopy of colchicine showed a strong band with maximum at 510 nm appearing at tau = 0. It disappeared within few hundred femtoseconds, leaving a broad structureless band with a maximum around 470 urn. A second band is observed around 410 nm. The analysis in time showed that the 510-nm component appeared instantaneously and decayed following a biexponential low with time constants of 300 +/- 100 fs and 40 ps. The kinetics at 420 nm has a measurable rise lime of 300 +/- 150 fs. Quantum mechanical calculations on colchicine showed that this absorption is due to a S-1 --> S-11 transition. In thiocolchicine, the instantaneous formation of a structure with maxima out of the investigated spectral region was observed. A strong absorption around 650 nm indicated the presence of a band with a maximum at longer wavelengths (> 700 nm) and a peak around 380 nm, which partially coincides with the ground-state absorption and therefore strongly affected absorption around 650 nm and its rapid (similar to500 fs) decay by its bleaching. The instantaneous formation of an absorption was observed. At shorter wavelengths (400 nm), the t decay was fitted with a biexponential curve with the first time constant of about 80 ps. The second part of,the decay had a very long tail up to 500 ps. Transient spectroscopy and configuration interaction calculations are in agreement with a mechanism involving a disrotatory cyclization of colchicine in its first excited singlet state. The lack of reactivity observed in thiocolchicine was explained by considering the presence of efficient ISC to the triplet state

Nature-inspired indolyl-2-azabicyclo[2.2.2]oct-7-ene derivatives as promising agents for the attenuation of withdrawal symptoms: synthesis of 20-desethyl-20-hydroxymethyl-11-demethoxyibogaine

Microwave assisted Diels-Alder cycloaddition of 5-Br-N -benzylpyridinone (2) with methyl acrylate is described to gain an easy access to 7-bromo-2-benzyl-3-oxo-2-aza-5 or 6-carbomethoxy bicyclo[2.2.2]oct-7-enes (3)-(6). The preparation of the ibogaine analogue 20-desethyl-(20-endo)-hydroxymethyl-11-demethoxyibogaine (17) is described by stereoselective hydrogenation of the C(7)-C(8) double bond. Biological evaluation showed an interesting in vitro binding profile toward dopamine transporter, serotonin transporter and opioid receptor systems accompanied by an antiwithdrawal effect in mice for hydroxymethyl 7-indolyl-2-aza-bicyclo[2.2.2]oct-2-ene (14). The simplification of the ibogaine structure appears as a promising approach toward the design of compounds that could reduce the withdrawal symptoms

Jagged ligands enhance the pro-angiogenic activity of multiple myeloma cells

Multiple myeloma (MM) is an incurable plasma cell malignancy arising primarily within the bone marrow (BM). During MM progression, different modifications occur in the tumor cells and BM microenvironment, including the angiogenic shift characterized by the increased capability of endothelial cells to organize a network, migrate and express angiogenic factors, including vascular endothelial growth factor (VEGF). Here, we studied the functional outcome of the dysregulation of Notch ligands, Jagged1 and Jagged2, occurring during disease progression, on the angiogenic potential of MM cells and BM stromal cells (BMSCs). Jagged1\u20132 expression was modulated by RNA interference or soluble peptide administration, and the effects on the MM cell lines\u2019 ability to induce human pulmonary artery cells (HPAECs) angiogenesis or to indirectly increase the BMSC angiogenic potential was analyzed in vitro; in vivo validation was performed on a zebrafish model and MM patients\u2019 BM biopsies. Overall, our results indicate that the MM-derived Jagged ligands (1) increase the tumor cell angiogenic potential by directly triggering Notch activation in the HPAECs or stimulating the release of angiogenic factors, i.e., VEGF; and (2) stimulate the BMSCs to promote angiogenesis through VEGF secretion. The observed pro-angiogenic effect of Notch activation in the BM during MM progression provides further evidence of the potential of a therapy targeting the Jagged ligands

Lino e canapa: una fonte preziosa di nuovi prodotti ad alto valore aggiunto

Questo capitolo descrive i risultati conseguiti dai gruppi di ricerca dell'Universita' degli Studi di Milano e dell'Università degli Studi di Pavia nell'ambito del progetto VeLiCa. Le attività sperimentali hanno riguardato: 1) la realizzazione di biotrasformazioni catalizzate da lipasi per arricchire l'olio di canapa (Cannabis sativa L.) nella componente polinsatura al fine di ottenere concentrati di potenziale impiego alimentare/nutraceutico; 2) la valorizzazione dei panelli e delle farine residue derivanti dall'estrazione dell'olio dai semi di canapa e lino (Linum usitatissimum L.). Dalla canapa sono stati ottenuti, per trattamento enzimatico, idrolizzati proteici con attività antiossidante e proprietà di esaltatori di aroma; del lino è stata caratterizzata dal punto di vista chimico-fisico la componente polisaccaridica (mucillagini)