2,6-Di-tert-butyl-4-methylphenol → Ethyl 1-cyclopropyl-6,8-difluoro-7-vinyl-4-oxo-1,4-dihydro-quinoline-3-carboxylate

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Reaction Steps

Into a properly equipped flask was added 2.0 g (4.52 mmoles) Compound 3 and 24 ml dry THF. While flushing with nitrogen, 1.36 ml (4.68 mmoles) of vinyltributyltin was added along with 0.58 g (13.56 mmoles) LiCl and, 0.070 g (0.10 mmoles) Pd(PPh3)2Cl2. A couple crystals of 2,6-di-tert-butyl4-methyl phenol was also added just before heating. The reaction was heated to 60°-65° C. for 21 hours after which it turned black and a black precipitate was present. The reaction was cooled to room temperature and 1 ml of pyridine and 2 ml of pyridinium fluoride were added and the reaction allowed to stir overnight. THF was added and the reaction filtered through a celite pad and poured into water. The precipitate formed was collected to give 2.0 g of crude product which was taken up in CH2Cl2 and run through a short silica gel column eluting with dichloromethane to start and slowly increasing polarity to 1% methanol in dichloromethane. The fractions containing product were evaporated in vacuo to give 1.07 g of (4), 74% yield.

Provenance & Evidence