3,4-dihydroxyspiro[cyclopent-3-ene-1,3'-pyrrolo[2,3-b]pyridin]-2'(1'H)-one

tert-butyl 2'-oxo-1',2'-dihydro-1H-spiro[piperidine-4,3'-pyrrolo[2,3-b]pyridine]-1-carboxylate

烟酸

2-氯烟酰氯

2-氯烟酸