tert-butyl (3S)-1,2,3,4-tetrahydroisoquinoline-3-carboxylate

Conditions: temp:-50.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A cooled and freshly distilled solution of 270 mg of pyruvic acid in 5 ml of chloroform is rapidly stirred into a solution of 700 mg of Tic-OBut and 630 mg of dicyclohexylcarbodiimide in 15 ml of anhydrous chloroform, the latter solution having been cooled to -50° C. The mixture is left for 16 hours in a deep-freezing cabinet (-20° C.), and the precipitated dicyclohexylurea is filtered off. The solution is washed with KHSO4 solution and then with KHCO3 solution, dried over Na2SO4, and concentrated in vacuo. The compound (oil) contains a little dicyclohexylurea, and was analyzed by chromatography over silica gel in the system CHCl3 /CH3OH 15:1. A cooled the precipitated dicyclohexylurea is filtered off The solution is washed with KHSO4 solution with KHCO3 solution, dried over Na2SO4 concentrated in vacuo

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

Procedure: 3.73 g of tert.-butyl (3S)-1,2,3,4-tetrahydroisoquinoline-3-carboxylate, 3.58 g of 3-benzoylthio-2-methylpropionic acid and 2.16 g of 1-hydroxybenzotriazole are dissolved in 60 ml of tetrahydrofuran, and a solution of 3.3 g of dicyclohexylcarbodiimide in 10 ml of tetrahydrofuran is added dropwise thereto at -15° C. After said dropwise addition, the mixture is stirred at a temperature below -10° C. for 3 hours and then at room temperature overnight. Insoluble materials are removed by filtration. The filtrate is distilled under reduced pressure to remove solvent. Water is added to the residue obtained, and the aqueous mixture is extracted with ethyl acetate. The extract is washed with an aqueous 3 % citric acid solution, water, an aqueous sodium bicarbonate solution and water, sucessively. Then, the extract is dried and distilled to remove solvent. The residue thus obtained is purified by silica gel column chromatography. 5.18 g of ter.-butyl (3S)-2-(3-benzoylthio-2-methylpropionyl)-1,2,3,4-tetrahydroisoquinoline-3-carboxylate are thereby obtained as colorless oil. at -15° C addition at room temperature overnight Insoluble materials are removed by filtration The filtrate is distilled under reduced pressure to remove solvent Water is added to the residue obtained the aqueous mixture is extracted with ethyl acetate The extract is washed with an aqueous 3 % citric acid solution, water Then, the extract is dried distilled to remove solvent The residue thus obtained is purified by silica gel column chromatography

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

Procedure: 3.73 g of tert.-butyl (3S)-1,2,3,4-tetrahydroisoquinoline-3-carboxylate, 3.58 g of 3-benzoylthio-2-methylpropionic acid and 2.16 g of 1-hydroxybenzotriazole are dissolved in 60 ml of tetrahydrofuran, and a solution of 3.3 g of dicyclohexylcarbodiimide in 10 ml of tetrahydrofuran is added dropwise thereto at -15° C. After said dropwise addition, the mixture is stirred at a temperature below -10° C. for 3 hours and then at room temperature overnight. Insoluble materials are removed by filtration. The filtrate is distilled under reduced pressure to remove solvent. Water is added to the residue obtained, and the aqueous mixture is extracted with ethyl acetate. The extract is washed with an aqueous 3 % citric acid solution, water, an aqueous sodium bicarbonate solution and water, sucessively. Then, the extract is dried and distilled to remove solvent. The residue thus obtained is purified by silica gel column chromatography. 5.18 g of ter.-butyl (3S)-2-(3-benzoylthio-2-methylpropionyl)-1,2,3,4-tetrahydroisoquinoline-3-carboxylate are thereby obtained as colorless oil. at -15° C addition at room temperature overnight Insoluble materials are removed by filtration The filtrate is distilled under reduced pressure to remove solvent Water is added to the residue obtained the aqueous mixture is extracted with ethyl acetate The extract is washed with an aqueous 3 % citric acid solution, water Then, the extract is dried distilled to remove solvent The residue thus obtained is purified by silica gel column chromatography

Conditions: temp:-50.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A cooled and freshly distilled solution of 270 mg of pyruvic acid in 5 ml of chloroform is rapidly stirred into a solution of 700 mg of Tic-OBut and 630 mg of dicyclohexylcarbodiimide in 15 ml of anhydrous chloroform, the latter solution having been cooled to -50° C. The mixture is left for 16 hours in a deep-freezing cabinet (-20° C.), and the precipitated dicyclohexylurea is filtered off. The solution is washed with KHSO4 solution and then with KHCO3 solution, dried over Na2SO4, and concentrated in vacuo. The compound (oil) contains a little dicyclohexylurea, and was analyzed by chromatography over silica gel in the system CHCl3 /CH3OH 15:1. A cooled the precipitated dicyclohexylurea is filtered off The solution is washed with KHSO4 solution with KHCO3 solution, dried over Na2SO4 concentrated in vacuo

Conditions: temp:-50.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A cooled and freshly distilled solution of 270 mg of pyruvic acid in 5 ml of chloroform is rapidly stirred into a solution of 700 mg of Tic-OBut and 630 mg of dicyclohexylcarbodiimide in 15 ml of anhydrous chloroform, the latter solution having been cooled to -50° C. The mixture is left for 16 hours in a deep-freezing cabinet (-20° C.), and the precipitated dicyclohexylurea is filtered off. The solution is washed with KHSO4 solution and then with KHCO3 solution, dried over Na2SO4, and concentrated in vacuo. The compound (oil) contains a little dicyclohexylurea, and was analyzed by chromatography over silica gel in the system CHCl3 /CH3OH 15:1. A cooled the precipitated dicyclohexylurea is filtered off The solution is washed with KHSO4 solution with KHCO3 solution, dried over Na2SO4 concentrated in vacuo

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

Procedure: 3.73 g of tert.-butyl (3S)-1,2,3,4-tetrahydroisoquinoline-3-carboxylate, 3.58 g of 3-benzoylthio-2-methylpropionic acid and 2.16 g of 1-hydroxybenzotriazole are dissolved in 60 ml of tetrahydrofuran, and a solution of 3.3 g of dicyclohexylcarbodiimide in 10 ml of tetrahydrofuran is added dropwise thereto at -15° C. After said dropwise addition, the mixture is stirred at a temperature below -10° C. for 3 hours and then at room temperature overnight. Insoluble materials are removed by filtration. The filtrate is distilled under reduced pressure to remove solvent. Water is added to the residue obtained, and the aqueous mixture is extracted with ethyl acetate. The extract is washed with an aqueous 3 % citric acid solution, water, an aqueous sodium bicarbonate solution and water, sucessively. Then, the extract is dried and distilled to remove solvent. The residue thus obtained is purified by silica gel column chromatography. 5.18 g of ter.-butyl (3S)-2-(3-benzoylthio-2-methylpropionyl)-1,2,3,4-tetrahydroisoquinoline-3-carboxylate are thereby obtained as colorless oil. at -15° C addition at room temperature overnight Insoluble materials are removed by filtration The filtrate is distilled under reduced pressure to remove solvent Water is added to the residue obtained the aqueous mixture is extracted with ethyl acetate The extract is washed with an aqueous 3 % citric acid solution, water Then, the extract is dried distilled to remove solvent The residue thus obtained is purified by silica gel column chromatography