Pyridine → HCID 20200643, compound

Participants

Reaction Steps

To a toluene solution of 5-(1-hydroxy-1-methylprop-2-yn-1-yl)-2-pyrrolidone at room temperature was added 4.0 equivalents of pyridine and 1.5 equivalents of thionyl chloride. The reaction mixture was left for four days. It was then quenched with cold water, extracted repeatedly with ethyl acetate and the organic extract washed once with water, brine, dried over anh. MgSO4 and concentrated to give an oil. Purification by chromatography over silica gel gave a 1:1 ratio of 5-(1-methyl-3-chloro-1,2-propadien-1-yl)-2-pyrrolidone (IR 1960 cm-1) and 5-(1-methyleneprop-2-yne-1-yl)-2-pyrrolidone (IR 2100 cm-1). The mixture was then refluxed in a 1:1 solution of THF: 20% HCl for 2 days, diluted with water, and washed with ether. The aqueous phase was passed through an ion-exchange column (Ag 50 W×8) eluting with 20% pyridine-water. The concentrate was then chromatographed on HPLC (RP-18) giving two diasteromeric allenes which separated under the HPLC conditions. 4-Amino-5-methyl-7-chloro-5,6-heptadienoic acid; IR (KBr): 1962, 1545 cm-1, 'H NMR (δD2O): 1.93 (d, 3H, J=2.2 Hz, CH3), 1.9-2.5 (m, 4H, CH2CH2), 3.9 (m, 1H, CHN), 6.49 (m, 1H, CH=C), mass spectrum (M+Cl 154), 102, 84; and 4-amino-5-methylene-6-heptynoic acid IR: 3165, 2130, 1610, 1540 cm-1 ; 'H NMR (δD2O): 1.9-2.5 (m-4H, CH2CH2), 2.58 (s, 1H, C=CH), 2.96 (m, 1H, HCN), 5.8 (d, 2H, J=7.3 Hz, H2C=C).

Provenance & Evidence