1-isocyanato-3-methylbut-2-ene

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

Procedure: To a stirred solution or partial solution of 2,5-thiazolidinedione (0.010 mol) in tetrahydrofuran (THF) is added neat (or a solution in dichloromethane or THF) (3-methyl-but-2-en-1-yl)-isocyanate (0.010 mol), prepared by allowing (3-methyl-but-2-en-1-yl)amine with 0.33 mol equivalents of triphosgene in dichloromethane optionally in the presence of a tertiary amine base or pyridine, and the mixture is stirred. Reaction progress may be followed by thin layer chromatography (TLC) or high performance liquid chromatography (HPLC). When a sufficient amount of desired product is formed, the mixture (or, optionally, the residue which is obtained after first rotary evaporating off the reaction solvent) is partitioned between ethyl acetate and an excess of about 0.1 M hydrochloric acid. The organic layer is washed with brine, dried over sodium sulfate, and rotary evaporated to give 3-(3-methyl-but-2-en-1-yl)aminocarbonyl-2,5-thiazolidinedione, which may be purified, if needed or desired, by chromatography on silica gel or crystallization. Reaction progress

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

Procedure: To a stirred solution or partial solution of 2,5-thiazolidinedione (0.010 mol) in tetrahydrofuran (THF) is added neat (or a solution in dichloromethane or THF) (3-methyl-but-2-en-1-yl)-isocyanate (0.010 mol), prepared by allowing (3-methyl-but-2-en-1-yl)amine with 0.33 mol equivalents of triphosgene in dichloromethane optionally in the presence of a tertiary amine base or pyridine, and the mixture is stirred. Reaction progress may be followed by thin layer chromatography (TLC) or high performance liquid chromatography (HPLC). When a sufficient amount of desired product is formed, the mixture (or, optionally, the residue which is obtained after first rotary evaporating off the reaction solvent) is partitioned between ethyl acetate and an excess of about 0.1 M hydrochloric acid. The organic layer is washed with brine, dried over sodium sulfate, and rotary evaporated to give 3-(3-methyl-but-2-en-1-yl)aminocarbonyl-2,5-thiazolidinedione, which may be purified, if needed or desired, by chromatography on silica gel or crystallization. Reaction progress

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

Procedure: To a stirred solution or partial solution of 2,5-thiazolidinedione (0.010 mol) in tetrahydrofuran (THF) is added neat (or a solution in dichloromethane or THF) (3-methyl-but-2-en-1-yl)-isocyanate (0.010 mol), prepared by allowing (3-methyl-but-2-en-1-yl)amine with 0.33 mol equivalents of triphosgene in dichloromethane optionally in the presence of a tertiary amine base or pyridine, and the mixture is stirred. Reaction progress may be followed by thin layer chromatography (TLC) or high performance liquid chromatography (HPLC). When a sufficient amount of desired product is formed, the mixture (or, optionally, the residue which is obtained after first rotary evaporating off the reaction solvent) is partitioned between ethyl acetate and an excess of about 0.1 M hydrochloric acid. The organic layer is washed with brine, dried over sodium sulfate, and rotary evaporated to give 3-(3-methyl-but-2-en-1-yl)aminocarbonyl-2,5-thiazolidinedione, which may be purified, if needed or desired, by chromatography on silica gel or crystallization. Reaction progress