Hydrochloric Acid → HCID 86736266, compound

Participants

Reaction Steps

53 g (0.25 mole) of ethyl alpha-formamido-2,3,5,6-tetrahydro-4H-pyran-Δ4,α -acetate and 14.5 g of phosphorous pentasulfide (P4S10) are suspended in 300 ml of anhydrous benzene. After boiling under reflux for 4 hours with stirring, the benzene solution is decanted off from insoluble material, treated with active carbon and filtered over "Hyflo-cel". After evaporating off the solvent, a brownish oil remains behind which distils at 130-135° C/0.5 mm Hg. In this way, there are obtained 30 g (yield 52% of theory) of ethyl 8-oxa-1-thia-3-azaspiro[4,5]-dec-2-ene-4carboxylate which is used without further purification for the continuation of the synthesis. I.1.c. alpha-Amino-4-mercapto-2,3,5,6-tetrahydro-4H-pyran-4acetic acid (formula III: n=m=2, X=0) 2 g (0.0087 mole) of ethyl 8-oxa-1-thia-3-azaspiro[4.5]-dec-2-ene-4-carboxylate are dissolved in 100 ml of 6 N hydrochloric acid. The reaction mixture is refluxed for 3 hours and is then concentrated in vacuo in a rotary evaporator. The gummy residue obtained is triturated 3 times with 50 ml of benzene, which are evaporated off under reduced pressure in order to eliminate remaining traces of water and hydrochloric acid. The residue is taken up in 100 ml of water and the solution is treated with "Norite" and then lyophilized. Trituration of the lyophilisate with dry diethyl ether gives 1.6 g of alpha-amino-4-mercapto-2,3,5,6-tetrahydro-4 H-pyran-4-acetic acid hydrochloride (yield: 80.5% of theory). The product gives a single spot in thin layer chromatography on silica (eluent: butanol, acetic acid, water: 4:1:1, Rf:0.35); M.P. 196-197° C (decomposition).

Provenance & Evidence