Lithium methoxide (3 cm3, 3mmol of 1.0M solution in methanol) was added to (11) (1.0 g, 2.8 mmol) in methanol (15 cm3) at 0 °C, with stirring, under an atmosphere of nitrogen. The mixture was stirred at room temperature for 67 h, then water (20 cm3) was added and the mixture extracted into dichloromethane (DCM). The DCM solution was dried (MgS04) and evaporated giving a solid ( 1.1 g) shown to consist of 4- methoxy-3,5-difluoro-2,6-dibromopyridine (22g) ( 19% ), 2,6-dibromo-4,5-dimethoxy-3- fluoropyridine (22h) (5%), (23b) (39% by comparison with authentic sample) and (23a) (36%). Neither column chromatography (eluting DCM and petrol 7: 3) nor preparative scale GLC ( 10% SE30, 140 oC) gave adequate separation of the products. However, a carbon nmr spectrum and GCMS of a mixture of (22g) and (23b) was obtained and the carbon spectra was assigned by comparison with that of (23b ).
Lithium Methoxide [865-34-9], LiOCH3, Mr 37.98, is a white solid that is soluble in methanol but virtually insoluble in aprotic organic solvents. It is commercially available as a 99 % fine crystalline solid and as 10 % solution in methanol. It can be used as base, especially as catalyst for transesterification reactions.
Employed in sol-gel synthesis of lithium borophosphates.
Lithium methoxide is used in sol-gel synthesis of lithium borophosphates. It is also useful for deprotonation reactions in organic synthesis. Further, it serves as a mild base in organic synthesis especially in transesterifications.
The most probable impurity is LiOH due to hydrolysis by moisture. It is important to keep the sample dry. It can be dried by keeping in a vacuum at 60-80o under dry N2 using an oil pump for a few hours. Store it under N2 in the cold. It should not have bands above 3000cm-1, IR has 1078, 2790, 2840 and 2930cm-1 in KBr. [Suebold J Org Chem 21 1561956, Beilstein 1 IV 1220, 1241.]
