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3. A new efficient route to Tolterodine

Author

Botteghi C, Corrias T., Marchetti M., and Paganelli S. Piccolo O.

Abstract

Tolterodine, an important urological drug, can be conveniently prepared starting from 1-((2-hydroxy-5-methyl)phenyl)-1-phenylethylene, accessible in high yield by alumina-promoted ortho alkenylation of p-cresol with phenylacetylene. The hydroformylation of this olefin, catalyzed by rhodium complexes both in homogeneous or in aqueous biphasic system, affords the desired linear aldehyde in about 80-90% yield. The reductive amination of this aldehyde, in the presence of HN(i-Pr)2 and Pd/C (5%) as the catalytic precursor at 4 atm H2 and 48°C, produces directly tolterodine in more than 90% yield. Some experiments of enantioselective hydroformylation of 1-(2-hydroxy-5-methylphenyl)-1-phenylethylene catalyzed by Rh(CO)2acac/(S,R)-Binaphos and other enantiopure ferrocenyldiphosphines afforded only low yields of the expected chiral aldehyde; unfortunately, the achieved ee did not exceed 8%. more...

Published
2002

4. Synthesis of a, w-epoxyaldehydes by hydroformylation of alpha, beta-epoxyalkenes

Author

Botteghi C., Marchetti M., Paganelli S., and Scognamillo S.

Abstract

Linear a,w-epoxyaldehydes with variable distance between the two functional groups, a class of interesting cross-linking agents for proteins, polysacharides and other polymeric compounds, can be conveniently prepared by hydroformylation of commercially available a,w- epoxyalkenes catalyzed by rhodium/phosphine complexes. For example, 1,2- epoxyhex-5-ene (2b) was converted into 6,7-epoxyheptanal (1b) with 75-99% yields in the presence of the catalytic system HRh(CO)(PPh3)3/Xantphos at 20 atm (CO/H2 = 1) and at 40°-100°C. Operating at 40°C practically regiospecific formation of the linear epoxyaldehyde was found. more...

Published
2002

5. Aqueous biphasic hydroformylkation catalysed by protein-rhodium complexes

Author

Bertucci C., Botteghi C., Giunta D., Marchetti M., and Paganelli S.

Abstract

The water soluble complex deriving from Rh(CO)2(acac) and Human Serum Albumin (HSA) resulted efficient in the hydroformylation of several olefin substrates. The chemoselectivity and regioselectivity were generally higher with respect to those obtained by using the classic catalytic systems like TPPTS-Rh(I) (TPPTS = triphenylphosphine – 3,3’,3’’ - trisulfonic acid trisodiumsalt). Styrene and 1-octene, for instance, were converted in almost quantitative yield into the corresponding oxo-aldehydes at 60°C and 70 atm (CO/H2 = 1) even at very low Rh(CO)2(acac)/HSA catalyst concentrations. The possibility of easily recovering the Rh(I) compound makes the system environmentally friend. Circular dichroism technique was useful in demonstrating the Rh(I) binding to the protein and to give information on the stability in solution of the catalytic system. Some other proteins have been used to replace HSA complexing agent for Rh (I). The results were less impressive with respect to those obtained using HSA and their complexes with Rh(I) were much less stable. more...

Published
2002