1,2-difluorobenzene

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:-70.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A 2.5M solution of butyllithium in hexane (4.5 mL, 11 mmol) was added dropwise with stirring to a solution of 1.00 mL (10.2 mmol) of 1,2-difluorobenzene in 10 mL of dry tetrahydrofuran cooled to -70° C. under a nitrogen atmosphere. After 10 min, 0.80 mL (11 mmol) of dimethyl disulfide was added dropwise with stirring. Another 11 mmol of 2.5M butyllithium was then added and, after 10 min, the reaction mixture was quenched by bubbling a stream of dry carbon dioxide into the solution. The resulting mixture was diluted with water and the mixture was washed with ether and then acidified with 1N aqueous hydrochloric acid. The resulting heavy white precipitate was recrystallized from a mixture of ethyl acetate and heptane to obtain 0.65 g (31 percent of theory) of the title compound as a white solid melting at 214-215° C. the reaction mixture was quenched by bubbling a stream of dry carbon dioxide into the solution The resulting mixture was diluted with water the mixture was washed with ether The resulting heavy white precipitate was recrystallized from a mixture of ethyl acetate and heptane

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: Using the same procedure and naphthalene-2,3-dicarboxylic anhydride and 1,2-difluorobenzene gives 2,3-difluoronaphthacene-5,12-dione.

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: 625 ml (1 mol) of 1.6 M BuLi are added dropwise at −78° C. to a solution of 114 g (1 mol) of 1,2-difluorobenzene in 1 l of dry tetrahydrofuran. After 1 hour, 140 ml (120 g, 1.1 mol) of trimethylsilyl chloride are slowly added dropwise at −78° C. The mixture is allowed to warm to room temperature overnight, and then 200 ml of methyl tert-butyl ether and 200 ml of water are added. The organic phase is washed with water (2×100 ml) and sat. NaCl (1×100 ml) and dried using magnesium sulfate, and the solvent is removed under reduced pressure. 170 g (91%) of 5 distil over from the residue at from 100 to 102° C./70 mbar. The organic phase is washed with water (2×100 ml) and sat. NaCl (1×100 ml) dried the solvent is removed under reduced pressure 170 g (91%) of 5 distil over from the residue at from 100 to 102° C./70 mbar

Conditions: temp:70.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A mechanically stirred mixture of 49.0 g (0.43 mole) of 1,2-difluorobenzene, 20.6 g (0.19 mole) of pyridine-4-carboxaldehyde and 80 ml of concentrated H2SO4 was heated at 70° C. for 21 hours. The reaction mixture was poured over ice, and the icy mixture was made basic with 50% NaOH. The resulting mixture was extracted with CH2Cl2 and the CH2Cl2 solution was dried (MgSO4). The solvent was removed in vacuo to give 54.94 g (89.8%) of a solid. This was recrystallized from a mixture of CH2Cl2 and hexane to give 44.82 g (74.3%) of a crystalline solid, mp 79°-82° C. Proton NMR showed that this sample contained ~5% of the 2,3-difluoro isomer. The reaction mixture was poured over ice The resulting mixture was extracted with CH2Cl2 the CH2Cl2 solution was dried (MgSO4) The solvent was removed in vacuo