The reactions of potassium 2-indolizinethiolates having an ester group at the 3-position with some electron deficient acetylenic compounds were investigated. Their Michael additions or Michael addition-cyclizations proceeded with the elimination of an ester group to provide the corresponding 2-vinylthioindolizine and 4H-thiino[2,3-b]indolizin-4-one derivatives.
The reactions of potassium 2-indolizinethiolates having an ester group at the 3-position with some electron deficient acetylenic compounds were investigated. Their Michael additions or Michael addition-cyclizations proceeded with the elimination of an ester group to provide the corresponding 2-vinylthioindolizine and 4H-thiino[2,3-b]indolizin-4-one derivatives.
Peparation of New Nitrogen-bridged Heterocycles. 21. A Facile Synthesis of 2-Indolizinethiols Using New Protecting Groups
Some indolizine derivatives having (2-cyanoethyl)thio or (2-ethoxycarbonylethyl)thio group at the 2-position were prepared in moderate to good yields starting from the corresponding pyridinium 1-(thiocarbonyl)methylides. The treatment of these indolizines with a strong base such as potassium t-butoxide in N,N-dimethylformamide (DMF) gave smoothly title compounds, 2-indolizinethiols, with the elimination