N-(2,4-Dimethylphenyl)acetamide → 3,4-Dihydro-2,6,8-trimethylquinazolin-4-one

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Reaction Steps

The quinazolinone used as starting material was obtained using the first part of the process described in Example 1 concerning the preparation of starting materials except that 2,4-dimethylacetanilide was used in place of 3,4-dimethylacetanilide. Only one isomer, 3,4-dihydro-2,6,8-trimethylquinazolin-4-one, was obtained. Sodium hydride (2.39 g) was added to a stirred suspension of the product thus obtained (9.3 g) in dimethylformamide (100 ml) and the mixture was stirred at laboratory temperature for 1 hour. A solution of chloromethyl pivalate (8.23 ml) in dimethylformamide (20 ml) was added and the mixture was stirred at laboratory temperature for 18 hours, then poured onto a mixture of ice water (350 ml). The precipitate was filtered off, dried and purified by chromatography on a silica gel column using methylene chloride as eluent. There was thus obtained 3,4-dihydro-2,6,8-trimethyl-3-pivaloyloxymethylquinazolin-4-one (8.7 g).

Provenance & Evidence