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3rd January 2012 @ 02:14
Attempts to improve the preparation of (rac)-O,O'-1,1'-binaphthyl-2,2'-diyl bis(dimethylcarbamothioate) (MNR19) - altering the amount of NaH used.

MNR19-1%20scheme.png

MNR19-2%20table.PNG

Hazard and Risk Assessment:
As for MNR15:- HIRAC MNR15

Procedure
MNR19-2


To an ice cooled solution of (rac)-1,1'-Bi(2-naphthol)(0.50 g, 1.75 mmol) in dry DMF (10 mL) under argon was added sodium hydride (60% oil dispersion) (0.21 g, 5.24 mmol). The reaction was allowed to warm to room temperature and stirred for 10 mins. N,N-dimethylthiocarbamoyl chloride (0.47 g, 3.84 mmol) at room temperature and the resulting mixture was heated to 85°C for 1.5 h.

The yellow-brown mixture was cooled to room temperature and poured into 1% aqueous KOH solution (30 mL) where a off white solid precipitated out instantly. The solid was filtered and washed with water and dissolved in DCM, dried over magnsium sulfate, filtered and concentrated to give a light fluffy foam that slowly crystallised.

MNR19-2 crude - clean enough with traces of DMF and grease

Crude - 0.551 g, 1.2 mmol, 69 %

MNR19-3%20table.PNG

Procedure
MNR19-3


To an ice cooled solution of (rac)-1,1'-Bi(2-naphthol)(0.50 g, 1.75 mmol) in dry DMF (10 mL) under argon was added sodium hydride (60% oil dispersion) (0.28 g, 6.98 mmol). The reaction was allowed to warm to room temperature and stirred for 10 mins. N,N-dimethylthiocarbamoyl chloride (0.47 g, 3.84 mmol) at room temperature and the resulting mixture was heated to 85°C for 1.5 h.

The yellow-brown mixture was cooled to room temperature and poured into 1% aqueous KOH solution (30 mL) where a off white solid precipitated out instantly. The solid was filtered and washed with water and dissolved in DCM, dried over magnsium sulfate, filtered and concentrated to give a light fluffy foam that slowly crystallised.

MNR19-3 crude - clean enough with traces of DMF and grease.


Crude - 0.616 g, 1.34 mmol, 74 %

Procedure
MNR19-4
16/01/2012

To an ice cooled solution of (rac)-1,1'-Bi(2-naphthol)(2.0 g, 6.98 mmol) in dry DMF (40 mL) under argon was added sodium hydride (60% oil dispersion) (1.12 g, 27.94 mmol). The reaction was allowed to warm to room temperature and stirred for 10 mins. N,N-dimethylthiocarbamoyl chloride (1.90 g, 15.37 mmol) at room temperature and the resulting mixture was heated to 85°C for 1.5 h.

The yellow-brown mixture was cooled to room temperature and poured into 1% aqueous KOH solution (40 mL) where a off white solid precipitated out instantly. The solid was filtered and washed with water and dissolved in DCM, dried over magnsium sulfate, filtered and concentrated to give a light fluffy foam that slowly crystallised.

MNR19-4 crude - clean enough with traces of DMF and grease.


Crude - 2.55 g, 5.54 mmol, 79 %
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Attached Files
MNR19-2 table.PNG
MNR19-3 table.PNG
mnr19-2_crude.pdf
mnr19-3_crude.pdf
mnr19-2_crude.zip
mnr19-3_crude.zip
mnr19-4_crude.pdf
mnr19-4_crude.zip