Gilman Color Test

Grignard and lithium reagents the copper intermediates do not react with Michler s ketone 40, 60, 69, 119) [Gilman Color Test I (123)]. 

When an aliquot of this solution is subjected to a Gilman color test,2 a wine-red color is obtained. 

Phenylisopropyl-hydroxylamine can be reduced to phenylisopropylamine as follows A solution of 6g (0.04 mole) of phenylisopropyl-hydroxylamine in 80 ml of absolute ether is treated with 1.9 g (0.05 mole) of LAH in 150 ml of absolute ether in the usual manner and refluxed for an additional hour. After cooling, a sample of the reaction mixture should give a positive Gilman-Shulze color test, indicating an excess of the hydride (this test is not necessary for you to perform). Hydrolysis was carried out with 400 ml of 20% aqueous sodium potassium tartrate and after separation of the layers, the aqueous portion is extracted with two additional 75 ml volumes of ether. Rectification yields 2.0 g of substituted phenylisopropylamine. JACS, 1837 (1952). 

Dry carbon dioxide gas is bubbled slowly under the surface of a cooled tetrahydrofnran solution of one mole of benzylmagnesium chloride complex until a negative Gilman Schultze color test results. The mixture is then heated to reflux, the addition of carbon dioxide is discontinued, and a further one mole of benzylmagnesium chloride complex is added rapidly (over a period of 20-40 minutes). After completion of addition, the mix is refluxed for 2-4 hours, cooled, and 100-200 mL. of toluene added. The organic solution and suspension is extracted by one 100-mL. portion of water and one 100-mL. portion of 10% sodium carbonate. On acidification of the aqueous extracts, phenylacetic acid is obtained. The organic layer is subjected to distillation to remove solvents and then to vacuum distillation. Dibenzyl ketone and a small amount of tribenzyl carbinol are obtained. 

Gilman s test for the presence of Grignard reagent is useful about 0.5 ml. of the ethereal solution is removed with a capillary dropping tube and treated with an equal volume of a 1% solution of Michler s ketone in dry benzene and then, slowly, with 1 ml. of water. Addition of several drops of a 0.2% solution of iodine in acetic acid then produces a characteristic greenish blue color if Grignard reagent was present. 

The Gilman test (38), a color test for the detection of a Grignard reagent, is performed on each preparation prior to its use in the synthesis of C-palmitic acid. First, 0.5 mL of the Grignard solution is treated at room temperature with an equal volume of a 1% solution of 4,4 -bis(di-methylamino)benzophenone (Michlers ketone) while shaking. The... 

SCHEME 26.20 Gilman—Swiss test (Color Test II). 

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