Ulf Tilstam

Efficient and environmentally friendly synthesis of 2-amino-imidazole

Abstract A new and efficient method for the preparation of 2-amino-imidazole 3 was developed. Starting from cheap commodities O -methyl-iso-urea sulphate and 2-aminoacetaldehyde-acetales the desired product is isolated through a very simple work-up in a good yield. This new procedure overcomes several technical and environmental problems of the traditional approaches to this molecule and is therefore very attractive for large-scale preparation.

A mild and efficient dehydrogenation of indolines

Abstract A new mild and efficient dehydrogenation of indolines to indoles has been developed. For the dehydrogenation trichloroisocyanuric acid is used in combination with DBU. After work-up with sodium hydrogen sulfite it was possible to obtain indole in an almost quantitative yield. The new method is also suitable for indolines bearing electron withdrawing or electron donating groups. Under the reaction conditions no ring chlorination was observed.

An efficient method for activation and recycling of trityl resins

A mild and efficient method for activation and recycling of trityl chloride resins has been developed. The recycling is performed under mild reaction conditions utilizing thionyl chloride as chlorinating agent. The method is useful for the recycling of the resin during solid phase peptide and organic synthesis.

An efficient synthesis of 17-epi-ethynylestradiol

An efficient synthesis has been developed yielding 17-epi-ethynylestradiol 2 in an overall yield of 17 %. The key derivatives 7a-c were prepared from estrone in four steps. Subsequently epoxides 7a,c were efficiently transformed into 2 via Takanos method.