3-Chlorobenzoic Acid → (Adamantane-1-ylmethyl)oxycarbonyldifluoromethanesulfonic acid tert-butylammonium salt

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Reaction Steps

Within a 1-L three-neck flask, 153 g (purity 86%, 345 mmol, 1.0 eq) of the (adamantane-1-ylmethyl)oxycarbonyldifluoromethanesulfinic acid tert-butylammonium salt obtained in Example 5-a was dissolved in 600 g of chloroform. To the resulting solution, 89 g (362 mmol, 1.05 eq) of 70% m-chlorobenzoic acid was slowly added at 0° C. This reaction solution was stirred for 1 hour at room temperature. After that, it was confirmed by 19F NMR of the reaction solution that: the (adamantane-1-ylmethyl)oxycarbonyldifluoromethanesulfonic acid tert-butylammonium salt was totally consumed; and there was no bromodifluoroacetic acid adamantane-1-ylmethyl ester detected as a by-product. The thus-obtained organic layer was washed with 200 g of 10% aqueous sodium sulfite solution, washed with 500 g of saturated sodium hydrogencarbonate solution and washed twice with 500 g of water. After distillation of chloroform from the washed organic layer, the solid residue was dissolved in a mixed solvent of chloroform, ethyl acetate and diisopropyl ether and then recrystallized. With this, 122 g of target (adamantane-1-ylmethyl)oxycarbonyldifluoromethanesulfonic acid tert-butylammonium salt was obtained. The purity of the target compound was 99%; and the yield of the target compound was 89%. No fluorine ion (F−) was detected from any liquid waste of this step. Further, 380 ppb of sodium ion (Na+) was detected from the (adamantane-1-ylmethyl)oxycarbonyldifluoromethanesulfonic acid tert-butylammonium salt obtained in this step.

Provenance & Evidence