Ethanol → Methyl 2-(but-3-ynylthio)acetate

Thioglycollic acid (6.0 g) was added to a stirred solution of sodium hydroxide (8.0 g) in ethanol (50 ml). But-3-ynyl methanesulphonate (7.4 g) was added and the mixture was stirred at 20° for 24 hours. The reaction mixture was poured into water and the aqueous mixture was extracted with diethyl ether. The aqueous alkaline extracts were acidified with hydrochloric acid and the mixture was extracted with diethyl ether. The ethereal extracts were dried over anhydrous magnesium sulphate and evaporated in vacuo. The resulting oil was stirred in dry dimethylformamide (100 ml) and anhydrous sodium carbonate (15 g) was added. Methyl iodide (7.0 ml) was added and the reaction mixture was stirred at 20° for 3 days. Water was added and the aqueous mixture was extracted with diethyl ether. The ethereal extracts were washed with water and dried over anhydrous magnesium sulphate. The solvent was removed in vacuo and the residue was chromatographed on silica, eluting with 1:4 diethylether: hexane. Methyl 2-(but-3-ynylthio)acetate was obtained as a colourless oil (1.2 g) (a small amount of methyl 2-(but-3-yn-1-ylthio)propionate was present). A mixture of methyl 2-(but-3-ynylthio)acetate (0.6 g) and sodium hydroxide solution (20 ml, 2N, 1:1 methanol:water) was stirred for 24 hours at 20°. Water was added and the aqueous mixture was extracted with diethyl ether. The aqueous alkaline extracts were acidified with hydrochloric acid and the mixture was extracted with diethyl ether. The ethereal extracts were dried over anhydrous magnesium sulphate and the solvent was removed in vacuo. 2-(But-3-ynylthio)acetic acid was obtained as a colourless oil (0.5 g). (A small amount of 2-(but-3-ynylthio)propionic acid was present.

1. extractionthe aqueous mixture was extracted with diethyl ether
2. extractionthe mixture was extracted with diethyl ether
3. dry with materialThe ethereal extracts were dried over anhydrous magnesium sulphate
4. customevaporated in vacuo
5. stirringThe resulting oil was stirred in dry dimethylformamide (100 ml)
6. additionanhydrous sodium carbonate (15 g) was added
7. additionMethyl iodide (7.0 ml) was added
8. stirringthe reaction mixture was stirred at 20° for 3 days
9. additionWater was added
10. extractionthe aqueous mixture was extracted with diethyl ether
11. washThe ethereal extracts were washed with water
12. dry with materialdried over anhydrous magnesium sulphate
13. customThe solvent was removed in vacuo
14. customthe residue was chromatographed on silica
15. washeluting with 1:4 diethylether

ORD record

ord-04f273b736a348ce860375a5e8096566

Source dataset

uspto-grants-1995_11

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US05466710