On August 27, 2021, Fu, Jiya; Zhang, Chuanbao; Zhao, Lili; Li, Ran; Deng, Yihang; Yuan, Jinfang; Wang, Yanbo; Zhu, Junyan published a patent.Name: 2-(2,3-Dihydro-1H-inden-1-ylidene)malononitrile The title of the patent was Preparation of spiro dihydrofluorene derivatives. And the patent contained the following:
The invention discloses a preparation of spiro dihydrofluorene derivative, which has the advantages of high efficiency, low cost and good application prospect. Spiro dihydrofluorene derivatives are shown in formula I, wherein R1 is selected from: CN or CO2 Me; R2 is selected from substituted Ph, substituted pyridyl, substituted furanyl, substituted thiophene or substituted naphthyl; R3 is selected from one of hydrogen, halogen, alkyl, trifluoromethyl, hydroxyl, alkoxy, nitro, ester, amino, acylamino, alkacyloxy, cyano, aryl, alkenyl, halobenzyloxy, halobenzylamine or halophenoxy; R4 is selected from one of hydrogen, halogen, alkyl, trifluoromethyl, alkoxy, nitro, ester, amino, cyano, aryl, alkenyl, halobenzyloxy, halobenzylamine or halophenoxy. Spiro dihydrofluorene derivatives were prepared via cyclization of 2-benzofuranone derivatives and 1-indene methylene malononitrile. The experimental process involved the reaction of 2-(2,3-Dihydro-1H-inden-1-ylidene)malononitrile(cas: 2510-01-2).Name: 2-(2,3-Dihydro-1H-inden-1-ylidene)malononitrile
The Article related to spiro dihydrofluorene preparation cyclization, Heterocyclic Compounds (One Hetero Atom): Spiro Compounds With One Hetero Atom In Each Ring and other aspects.Name: 2-(2,3-Dihydro-1H-inden-1-ylidene)malononitrile
Referemce:
Nitrile – Wikipedia,
Nitriles – Chemistry LibreTexts