3,7-dimethyl-1H-indole-5-carboxylic acid 、 2'-ethyl-3'-methyl-2'H-spiro[piperidine-4,5'-pyrano[3,2-c]pyrazol]-7'(6'H)-one hydrochloride 以23%的产率得到1-(3,7-dimethyl-1H-indole-5-carbonyl)-2'-ethyl-3'-methyl-2'H-spiro[piperidine-4,5'-pyrano[3,2-c]pyrazol]-7'(6'H)-one