4-isobutyloxazolidine-2,5-dione

Conditions: temp:125.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A mixture of 16.2 g. of 2-amino-3,4-dihydro-1(2H)-isoquinolinone (0.10 mole), 27 g. of m-methoxybenzimidic acid ethyl ester (0.15 mole) and 2.15 g. of the hydrochloride of m-methoxybenzimidic acid ethyl ester is heated under vacuum (200 mm Hg.) for 5 hours at about 90° C and for 2 hours at about 125° C. Then 3.50 g. of m-methoxybenzimidic acid ethyl ester (0.02 mole) is added and the mixture is heated for a further 16 hours at about 125° C under vacuum. All volatile materials are eliminated by distilling off at 125° C and 5 mm Hg. The solid residue may be used as such for the cyclization step or, after washing with aqueous sodium bicarbonate and water, may be purified by crystallization from ethanol to isolate the intermediate III, 2-(m-methoxybenzimidoylamino)-3,4-dihydro-1-(2H)-isoquinolinone (m.p. 176°-177° C). The crude reaction product is cyclized by heating for five hours in 150 ml. of ethanol containing 1.2 g. of 80% sodium hydride (0.040 mole). The reaction mixture is then evaporated to dryness in vacuo and then dissolved in dichloromethane. The organic solution after washing with water is evaporated and the crude residual compound is crystallized from 50% ethanol, yielding 20 g. (72%) of the title compound, m.p. 94°-96° C. A mixture of 16.2 g by distilling off at 125° C after washing with aqueous sodium bicarbonate and water may be purified by crystallization from ethanol

Conditions: temp:125.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A mixture of 16.2 g. of 2-amino-3,4-dihydro-1(2H)-isoquinolinone (0.10 mole), 27 g. of m-methoxybenzimidic acid ethyl ester (0.15 mole) and 2.15 g. of the hydrochloride of m-methoxybenzimidic acid ethyl ester is heated under vacuum (200 mm Hg.) for 5 hours at about 90° C. and for 2 hours at about 125° C. Then 3.50 g. of m-methoxybenzimidic acid ethyl ester (0.02 mole) is added and the mixture is heated for a further 16 hours at about 125° C. under vacuum. All volatile materials are eliminated by distilling off at 125° C. and 5 mm Hg. The solid residue may be used as such for the cyclization step or, after washing with aqueous sodium bicarbonate and water, may be purified by crystallization from ethanol to isolate the intermediate III, 2-(m-methoxybenzimidoylamino)-3,4-dihydro-1-(2H)-isoquinolinone (m.p. 176°-177° C.). The crude reaction product is cyclized by heating for five hours in 150 ml. of ethanol containing 1.2 g. of 80% sodium hydride (0.040 mole). The reaction mixture is then evaporated to dryness in vacuo and then dissolved in dichloromethane. The organic solution after washing with water is evaporated and the crude residual compound is crystallized from 50% ethanol, yielding 20 g. (72%) of the title compound, m.p. 94°-96° C. A mixture of 16.2 g by distilling off at 125° C. after washing with aqueous sodium bicarbonate and water may be purified by crystallization from ethanol

Conditions: temp:125.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A mixture of 16.2 g. of 2-amino-3,4-dihydro-1(2H)-isoquinolinone (0.10 mole), 27 g. of m-methoxybenzimidic acid ethyl ester (0.15 mole) and 2.15 g. of the hydrochloride of m-methoxybenzimidic acid ethyl ester is heated under vacuum (200 mm Hg.) for 5 hours at about 90° C and for 2 hours at about 125° C. Then 3.50 g. of m-methoxybenzimidic acid ethyl ester (0.02 mole) is added and the mixture is heated for a further 16 hours at about 125° C under vacuum. All volatile materials are eliminated by distilling off at 125° C and 5 mm Hg. The solid residue may be used as such for the cyclization step or, after washing with aqueous sodium bicarbonate and water, may be purified by crystallization from ethanol to isolate the intermediate III, 2-(m-methoxybenzimidoylamino)-3,4-dihydro-1-(2H)-isoquinolinone (m.p. 176°-177° C). The crude reaction product is cyclized by heating for five hours in 150 ml. of ethanol containing 1.2 g. of 80% sodium hydride (0.040 mole). The reaction mixture is then evaporated to dryness in vacuo and then dissolved in dichloromethane. The organic solution after washing with water is evaporated and the crude residual compound is crystallized from 50% ethanol, yielding 20 g. (72%) of the title compound, m.p. 94°-96° C. A mixture of 16.2 g by distilling off at 125° C after washing with aqueous sodium bicarbonate and water may be purified by crystallization from ethanol