Selective thioketalization process, process for preparing thioenol ethers from thioketals, and process for the preparation of thioketals
申请人:E.R. SQUIBB & SONS, INC.
公开号:EP0524813A1
公开(公告)日:1993-01-27
A selective thioketalization process for the preparation of a thioketal from a dione where one, but not the other, keto group of the dione is α,β-unsaturated, and where selective thioketalization occurs at the keto group of the dione which is not α,β-unsaturated, comprising the step of contacting the dione with a thiol, in the presence of a protic acid catalyst which is a complex of a Lewis acid and a protic source, wherein the temperature of the reaction medium is maintained below about 25°C during the reaction. Preferably, further, (i) the acid catalyst is employed in excess and/or (ii) the thiol is employed in excess. The inventive process may be employed, for example, in the preparation of a 3-keto,17-thioketalandrostene from the corresponding 3,17-diketoandrostene.
A process for the preparation of thioenolethers from thioketals, especially 3-keto,17-thioenoletherandrostenes from 3-keto,17-thioketalandrostenes, wherein the thioketal is contacted with a protic acid catalyst.
A process for the preparation of thioketals, especially mixed thioketals such as mixed 3-keto,17-thioketalandrostenes, from thioenolethers, comprising the step of contacting a thioenolether with a thiol in the presence of a protic acid catalyst.
一种选择性硫醚化过程,用于从二酮制备硫醚,其中二酮的一个但不是另一个酮基是α,β-不饱和的,选择性硫醚化发生在不是α,β-不饱和的酮基上,包括将二酮与硫醇接触,在存在Lewis酸和质子源的复合物的质子酸催化剂的情况下,反应介质的温度在反应过程中保持在大约25°C以下。最好,进一步,(i) 过量使用酸催化剂和/或 (ii) 过量使用硫醇。该创新过程可以用于从相应的3,17-二酮雄烯制备3-酮,17-硫醚雄烯。一种从硫醚制备硫烯醚的过程,特别是从3-酮,17-硫醚雄烯制备3-酮,17-硫烯醚雄烯的过程,其中硫醚与质子酸催化剂接触。一种从硫烯醚制备硫醚的过程,特别是从硫烯醚制备混合硫醚,例如混合的3-酮,17-硫醚雄烯,包括将硫烯醚与硫醇在质子酸催化剂的存在下接触的步骤。