L-(+)-Cysteine → S-(9H-Xanthen-9-yl)cysteine

A sample of 0.61 g of cysteine (5 mmole) was suspended in 100 ml of 1,2-dimethoxyethane and 2 ml of TFA. The suspension was stirred under nitrogen gas at room temperature until the solution became clear. To this clear solution was added 1 g of 9H-xanthen-9-ol (5.1 mmole) in one portion. The reaction mixture was stirred at room temperature for 30 minutes and was then neutralized to pH 7 by the addition of a saturated aqueous Na2CO3 solution. The mixture was then concentrated by rotary evaporation. The residue was diluted with 50 ml of water. The aqueous solution was treated with 10% aqueous citric acid solution to adjust the pH to 6. The mixture was stirred at room temperature for 1 hr. The resultant white solid was collected by filtration and was washed with 3×10 ml of water and 3×10 ml of ethyl acetate. The product was dried to yield 1.30 g of product.

1. stirringThe reaction mixture was stirred at room temperature for 30 minutes
2. concentrationThe mixture was then concentrated by rotary evaporation
3. additionThe residue was diluted with 50 ml of water
4. additionThe aqueous solution was treated with 10% aqueous citric acid solution
5. stirringThe mixture was stirred at room temperature for 1 hr
6. filtrationThe resultant white solid was collected by filtration
7. washwas washed with 3×10 ml of water and 3×10 ml of ethyl acetate
8. customThe product was dried

ORD record

ord-946029af8d8640cf8e47831f71bc71c6

Source dataset

uspto-grants-2010_06

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07745392B2