ChEBI: 9,10-dimethoxy-3-isobutyl-1,3,4,6,7,11b-hexahydro-2H-pyrido[2,1-a]isoquinolin-2-one is a benzoquinolizine that is 1,2,3,4,4a,9,10,10a-octahydrophenanthrene in which the carbon at position 10a is replaced by a nitrogen and which is substituted by an isobutyl group at position 2, an oxo group at position 3, and methoxy groups at positions 6 and 7. It is a benzoquinolizine, a cyclic ketone and a tertiary amino compound.
6,7-Dimethoxy-3,4-dihydroisoquinoline hydrochloride (118.2 kg) was dissolved in water (3 volumes). A solution of 3-((dimethylamino)methyl)-5-methylhexan-2-one (99.1 kg) in n-heptane (1.5 vol) was added, and the reaction mixture was stirred vigorously at 35 °C for at least 48 hours until the amount of 6,7-dimethoxy-3,4-dihydroisoquinoline was reduced to less than 10% of the initial amount (as detected by a standard solution). After completion of the reaction, the solid product was collected by filtration, washed sequentially with water and n-heptane, and then dried under vacuum to afford 3-isobutyl-9,10-dimethoxy-3,4,6,7-tetrahydro-1H-pyrido[2,1-a]isoquinolin-2(11bH)-one (141.1 kg, 85.6% yield).
[1] Patent: US2017/183346, 2017, A1. Location in patent: Paragraph 0165
[2] Patent: US2017/183346, 2017, A1. Location in patent: Paragraph 0162; 0164
[3] Patent: CN107698582, 2018, A. Location in patent: Paragraph 0019
[4] Journal of Labelled Compounds and Radiopharmaceuticals, 2011, vol. 54, # 7, p. 367 - 370
