Synthesis of a Key Intermediate for D-Biotin via 1,3-Cycloaddition of a Thiocarbonyl Ylide and Sila-Pummerer Rearrangement
摘要:
An efficient preparation of a d-biotin intermediate, (+/-)-(3aalpha,4alpha,6aalpha)-1,3-dibenzyl-3a,4,6,6a-tetrahydro-4-hydroxy-1H-thieno[3,4-d]imidazol-2(3H)-one was accomplished by use of 1,3-cycloaddition of a thiocarbonyl ylide, Curtius rearrangement and sila-Pummerer rearrangement. Addition of p-toluenesulfonic acid was found to be effective to promote sila-Pummerer rearrangement of sterically unfavorable anti-2-trimethylsilyl sulfoxide.
Thiocarbonylylide was found to be generated by thermolysis of bromo(trimethylsilylmethylthio)methyltrimethylsilane and its 1,3-cyclo-addition provided a new method for synthesis of tetrahydrothiophenes.
The present invention relates to the use of novel pyrrolopyrazine derivatives of Formula I,
wherein the variables Q1, R, and X are defined as described herein, which inhibit JAK and SYK and are useful for the treatment of auto-immune and inflammatory diseases.