Purification, general procedures carboxylic

The described two-step procedure is uncomplicated and can be carried out in 1 day to give in good yield a product that does not require any further purification. This procedure has been used for the preparation of 3-methyl-, 9-methyl-, and 6-methoxy-l,2,3,4-tetrahydro-j3-carboline and has been modified to obtain 9-phenyl-l,2,3,4-tetrahydro-j3-carboline. The method is generally applicable to the preparation of other 1-unsubstituted tetrahydro-/3-carbolines providing the 1-carboxylic acid precursor is not insoluble in the hot acid used to effect decarboxylation. 

When treated with concentrated alkali, acetoacetic ester is converted into two moles of sodium acetate, (a) Outline all steps in a likely mechanism for this reaction. (Hint See Sec. 21.11 and Problem 5.8, p. 170.) (b) Substituted acetoacetic esters also undergo this reaction. Outline the steps in a general synthetic route from acetoacetic ester to carboxylic acids, (c) Outline the steps in the synthesis of 2-hexanone via acetoacetic ester. What acids will be formed as by-products Outline a procedure for purification of the desired ketone. (Remember that the alkylation is carried out in alcohol that NaBr is formed that aqueous base is used for hydrolysis and that ethyl alcohol is a product of the hydrolysis.)... 

Fatty acids, soaps and fatty acid methyl esters are the most extensively used oleochemicals [13]. The free fatty acids are prepared by hydrolysis of oils and fats by alkalis. This procedure named saponification proceeds at high temperature and pressure and leads to crude soaps the acidification of which gives fatty acids. They are subjected to various purification procedures, and finally isolated individually or as mixtures of carboxylic acids of the general formula RCOOH or as soaps RCOOM. The carboxylic acid methyl esters can be produced in two ways by esterification of the isolated carboxylic acid with methanol or by low-temperature... 

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