L-Tryptophan, methyl ester, hydrochloride (1:1)

Methyl L-tryptophanate hydrochloride is White to off-white powder

General procedure: Compounds 6–8 were synthesized using the following general procedure reported by Maiti and Banerjee [50]: a solution of amino acid (18.2mmol) in MeOH (20mL) was stirred at 0°C. Thionyl chloride (1.6mL, 22mmol) was added dropwise over 10min. The reaction mixture was then allowed to warm to room temperature before being heated under reflux for 3h. The solvent and volatiles were evaporated under reduced pressure and the product was triturated with ethyl acetate to give the methyl ester hydrochloride salt as a colorless solid (100percent). 50 ml of anhydrous methanol was added dropwise to a solution of 3.75 ml (50 mmol) of thionyl chloride in an ice bath, After completion of the dropwise addition in 30 min, 9.20 g (42 mmol) of L-tryptophan was added in portions, After stirring at room temperature for 24 h, TLC (CHCl3: MeOH = 2: 3) was monitored until the disappearance of the starting material.The pump was pumped off the unreacted sulfoxides SOCl2 and HCl, repeatedly triturated with ether to give a white solid which was recrystallized from methanol-ether to give L-tryptophan methyl ester hydrochloride as a colorless solid. The yield is between 85-99percent.the 20.4g (0.1mol) tryptophan, 20ml dichloroethane and Step 2) After the resultant filtrate rotary evaporated (i.e., mother liquor) into 250ml three-necked flask, at a rate of 1.25ml / s of hydrogen chloride gas, at room temperature for 0.5h.after which 4.16g (0.13mol) of methanol into three-necked flask, continuing to pass hydrogen chloride gas (0.05ml / s), under reflux conditions, dichloroethane distilled water (i.e., water with azeotropic process after evaporation of the mixture), in dry dichloroethane was added dropwise to the reaction system at the same rate, the amount of the reaction system is maintained substantially constant dichloroethane, for 3 hours; total consumption of about dichloroethane 190ml.The resulting reaction solution was cooled to room temperature and rotary evaporated under reduced pressure to remove the reaction solution remaining in dichloroethane and methanol, at -10 cooling the precipitated solid was recrystallized with dichloroethane ice (in an amount of 20ml) washed , filtered, and the filtrate and filter cake were obtained; the resulting cake was dried, to obtain tryptophan methyl ester hydrochloride 25.4g (0.0998mol), a yield of 99.8percent.General procedure: Lysine hydrochloride (2 g, 10.95 mmol) was weighed into a roundbottom flask together with 80 mL methanol. The resulting suspension was then cooled to 0 °C on ice, before dropwise addition of thionyl chloride 8 mL (110 mmol). Upon addition the reaction mixtureturned homogenous. Subsequently, the flask was fitted with a reflux condenser and heated to refluxovernight. After allowing the mixture to reach room temperature, the solvent was removed underreduced pressure. The crude solid was then placed under high vacuum overnight to afford lysinemethyl ester dihydrochloride as a white solid (2.3 g, 9.83 mmol, 96percent).To a suspension of 2.04 g (10 mmol) of commercial L-tryptophan (6) in 50 mL of MeOH was stirred at 0 °C. Thionyl chloride (0.88 mL, 12 mmol) was added dropwise over 10 min. The reaction mixture was then allowed to warm to room temperature before being heated under reflux for 3 h. The solvent and volatiles were evaporated under reduced pressure and the product was triturated with ethyl acetate to give the methyl ester hydrochloride salt as a colorless solid. The pure product was obtained in 95percent yield. 100 mL of anhydrous methanol and L-tryptophan (10 g, 0.05 mol) were added.Thionyl chloride (7.1 g, 0.06 mol) was slowly added dropwise at room temperature, and the reaction was continued at 50° C. for 3 h.After the reaction, add 100 mL of isopropyl ether, cool to 0-5°C, crystallize for 1 hour, filter, wash with isopropyl ether, and vacuum dry to obtain 10.5g of compound 1 in a yield of 105percent.

Amino acid derivative that may be used to prepare the corresponding amino acid amide L-Tryptophanamide Hydrochloride (Cat. #T89550)

Molecular Weight:254.71
Hydrogen Bond Donor Count:3
Hydrogen Bond Acceptor Count:3
Rotatable Bond Count:4
Exact Mass:254.0822054
Monoisotopic Mass:254.0822054
Topological Polar Surface Area:68.1
Heavy Atom Count:17
Complexity:257
Defined Atom Stereocenter Count:1
Covalently-Bonded Unit Count:2
Compound Is Canonicalized:Yes