Remigiusz Żurawiński

Biocatalytic syntheses of chiral non-racemic 2-hydroxyalkanephosphonates

A series of 2-oxoalkanephosphonates 2 were screened for reduction with Geotrichum candidum. Only diethyl 2-oxopropanephosphonate 2a underwent asymmetric reduction to give (+)-(R)-diethyl 2-hydroxypropanephosphonate 3a with 98% e.e. In turn, a series of racemic 2-hydroxyalkanephosphonates 3 were acetylated under kinetic resolution conditions in the presence of various lipases to give the corresponding 2-acetoxyalkanephosphonates 4 and recovered alcohols 3 in good yields and with e.e. up to 93%.

Facile synthesis of fluorescent distyrylnaphthalene derivatives for bioapplications

A series of novel 2,6-bis(4-aminostyryl)naphthalene based derivatives were synthesized and their spectroscopic properties investigated. Due to their low cytotoxicity, suitable optical properties and potential affinity towards biological structures these derivatives were proved to be promising dyes for application in fluorescence-based bioimaging. Selective intercalation of the tested compounds into cell membranes was revealed by fluorescence microscopy.

A new and expeditious synthesis of all enantiomerically pure stereoisomers of rosaprostol, an antiulcer drug

Summary Four enantiomerically pure stereoisomers of rosaprostol (1), an antiulcer drug, were efficiently synthesized from the enantiomers of 2-(dimethoxyphosphoryl)-3-hexylcyclopentanone (3) as chiral substrates. The latter were obtained by resolution of racemic 3 with (+)-(R)-1-(1-naphthyl)ethylamine. The conversion of (+)-3 into rosaprostol stereoisomer (−)-1a was accomplished in four steps in 56% overall yield. According to the same protocol, the second stereoisomer (+)-1c was obtained from (−)-3 in 55% overall yield. A slightly improved procedure of the last two steps of the transformation of (+)-3 into (−)-1a allowed an increase in the overall yield to 64%. The remaining two stereoisomers, (−)-1b and (+)-1d, were obtained from (−)-1a and (+)-1c in 71 and 68% yield, respectively, by a two-reaction sequence, in which a Mitsunobu inversion of configuration at C-5 was the key step.

Synthesis of Enantiomerically Pure Stereomers of Rosaprostol.

Enantiopure stereomers of rosaprostol 1, an antiulcer drug, were synthesized from diastereomeric building blocks (-)-5a and (+)-5b. Conversion of (-)-5a into rosaprostol stereomer (-)-(1S,2R,5R)-1a was accomplished in nine steps in 18% overall yield. In this sequence, fully diastereoselective hydrogeneration of the endocyclic carbon double bond in the cyclopentenone ring was key, generating a new stereogenic center (C-2 in 1a). C-5 epimeric rosaprostol (-)-(1S,2R,5S)-1b was obtained from (-)-1a in 72% yield by a two-reaction sequence involving methylation and one-pot Mitsunobu esterification-hydrolysis.

Molecular interactions in 3-carboxy-2-diphenylphosphinoylcyclopentanone

The results of the X-ray structure analysis of the title compound (I) have been reported in [Synthesis (1997) 356]. Now we continue our efforts to understand the energy situation and the arrangements in the crystal, which will be strongly influenced by the formation of hydrogen bonds with the help of the results of theoretical calculations. Furthermore, the IR spectroscopic measurements will be discussed in comparison to the X-ray data. The IR experiments elucidate the molecular arrangement in solution. Using different solvents, equilibrium states with coexisting conformational and associative arrangements were observed. Unexpectedly, the alternative use of the solvents CHCl(3) or CDCl(3) has different influence on the equilibrium arrangement of I in solution.

2.08 – Alkylphosphorus Compounds

This chapter describes the published methods of synthesis and transformations of organophosphorus compounds containing at least one alkyl–phosphorus bond, during the years 1995–2003. Some earlier references are also included to give a background for the examples discussed. Thus, the syntheses of primary, secondary, and tertiary phosphines, including tricoordinate alkylphosphorus halides as well as quaternary phosphonium salts, are comprehensively presented. Separate subsections are devoted to the preparation of optically active secondary and tertiary phosphines. Among the tetracoordinate alkylphosphorus compounds those containing a phosphorus–heteroatom bond, such as PO, PN, PS, PSe, and PTe, are discussed. Special subsections deal with the synthesis of alkylphosphorus derivatives containing main group elements belonging to group 13 (B, Al, Ga, In), group 14 (Si, Ge, Sn, Pb), and group 15 (As, Sb, Bi). The latter also covers the compounds with a PP bond. Finally, the newly synthesized penta and hexacoordinate alkylphosphorus derivatives are also presented.

Functions Containing at Least One Phosphorus, Arsenic, Antimony or Bismuth, and No Halogen, Chalcogen or Nitrogen

The chapter describes the methods of synthesis of acyclic and cyclic bisphosphino alkenes published during the years 1995–2003. It also covers the methods of synthesis and transformations of the bisphosphino alkenes containing various combinations of arsenic and antimony as well as metalloids (silicon, germanium, and boron). A major part of this chapter deals with the synthesis of metal derivatives of acyclic and cyclic bisphospino alkenes. Thus, the compounds containing group 1 metals (Li, Na, K), group 2 metals (Mg, Ba, Ca), group 13 metals (Ga, Tl), and group 14 metals (Sn, Pb) are discussed. A special subsection is devoted to the transition metal (group 3–12 metals) complexes with bisphosphino alkenes and their coordination modes.

Alkynylnitrogen and -phosphorus Compounds

This chapter describes preparative approaches for the synthesis of alkynylnitrogen and alkynylphosphorus compounds. The first part of this chapter deals with protocols which have been applied for the preparation of alkynylamines and their salts including primary, secondary, and tertiary ynamines. It is followed by presentation of procedures to obtain alkynylnitrogen compounds with an NY function such as N-methylene ynamines, azoalkynes, alkynyl azides, and alkynyl isocyanates. The second part devoted to alkynylphosphorus compounds begins with a summary of synthetic approaches to alkynylphosphines. It is followed by subchapters presenting the synthetic procedures leading to alkynylphosphonium salts, derivatives with alkynyl-PX2 functions, compounds having alkynyl (R)P-X functions, alkynylphosphine oxides and imides, and finally alkynylphosphonates.