Ethyl Acetate → HCID 59785001, compound

Participants

Reaction Conditions

Reaction Steps

A mixture of 2-Chloro-8-methoxy-5,6-dihydro-benzo[h]quinazoline (2, 5.0 g, 20.27 mM), 3-Amino-1H-pyrazole-4-carboxylic acid ethyl ester (3.14 g, 20.27 mM), Cs2CO3 (8.59 g, 26.35 mM) in DMF (40 ml) was stirred at 100° C. for 2.5 hr then cooled to room temperature and diluted with water (400 ml). The resulting precipitate was isolated via filtration and the solid washed with water (3×50 mL) then methanol (3×30 ml). The solid was dried under reduced pressure which was comprised of a 7:3 mixture of 3-Amino-1-(8-methoxy-5,6-dihydro-benzo[h]quinazolin-2-yl)-1H-pyrazole-4-carboxylic acid ethyl ester(3) and it's isomer 5-Amino-1-(5,6-dihydro-benzo[h]quinazolin-2-yl)-1H-pyrazole-4-carboxylic acid ethyl ester identical to the material prepared in preparation 6 below. The solid was then crystallized from dichloromethane (40 ml) to give the slower (TLC, EtOAc) of two isomers 3-Amino-1-(8-methoxy-5,6-dihydro-benzo[h]quinazolin-2-yl)-1H-pyrazole-4-carboxylic acid ethyl ester (3, 4.0 g, 2 crops, 54% yield). ES-MS MH+ 366. The mother liquors may be purified via chromatography on silica eluting with ethyl acetate to provide the faster isomer 5-Amino-1-(5,6-dihydro-benzo[h]quinazolin-2-yl)-1H-pyrazole-4-carboxylic acid ethyl ester.

Provenance & Evidence