Tetrahydrofuran → Prazosin

Temperature

-20 °C

In a 100 ml. flask equipped with thermometer and drying tube was charged 10 ml. of dry tetrahydrofuran and 0.5 ml. (6.2 mmoles) of furan. The solution was cooled to -20° C. and 2.8 ml. (6.2 l mmoles) of n-butyl lithium in hexane was added. To the resulting light amber mixture was added 400 mg. (1.24 mmoles) of 2-(4-cyanopiperazin-1-yl)-4-amino-6,7-dimethoxyquinazoline dissolved in 30 ml. of dry tetrahydrofuran. After the addition was complete, the reaction mixture was allowed to warm to room temperature while stirring overnight. The reaction was quenched into 88 ml. of 2N hydrochloric acid, washed with 100 ml. of chloroform, adjusted to pH 10 with aqueous sodium hydroxide solution and extracted twice with 100 ml. portions of chloroform. The aqueous phase was concentrated in vacuo to about 2 ml. and filtered to afford 15 mg of the title compound, M.P. 263°-264° C. The infrared spectrum and thin-layer chromatography behavior were identical to that of an authentic specimen.

1. customflask equipped with thermometer
2. customdrying tube
3. additionwas charged 10 ml
4. additionTo the resulting light amber mixture was added 400 mg
5. additionAfter the addition
6. temperatureto warm to room temperature
7. customThe reaction was quenched into 88 ml
8. washof 2N hydrochloric acid, washed with 100 ml
9. extractionextracted twice with 100 ml
10. concentrationThe aqueous phase was concentrated in vacuo to about 2 ml
11. filtrationand filtered

ORD record

ord-771bb9c0bbf2475b8e3e44fe2de53465

Source dataset

uspto-grants-1977_12

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US04062844