Synthetic studies on lycoricidine and related compounds. I. Synthesis of 4aH-r,2-H-cis,2-hydroxy-8,9-methylenedioxy-2,3,4,4a-tetrahydro-6(5H)-phenanthridone.

Efficient Synthesis of Tetrahydro-β-carbolin-1-one and Dihydroisoquinolin-1-one Derivatives as Versatile Intermediates

“…The intramolecular capture of an isocyanate intermediate generated from the corresponding carboxylic acid has been reported for both cinnamic 41 and dihydrocinnamic acid derivatives. 28,[42][43][44][45][46][47] The conditions previously described for substrates possessing a tethered indole group were extended to those with a pendant aromatic substituent. The low yield was due to problems of isolation resulting from poor solubility.…”

“…1 Methylenedioxy-3,4-dihydro-2H-isoquinolin-1-one (2a) Following the General Procedure using carboxylic acid 20a gave the lactam 2a (772 mg, 81%) as a white solid; mp 185-187 °C (EtOAc) (Lit. 45…”

“…Following the procedure reported by Kimoto et al, 45 , and the solvent removed to afford a solid. In addition, the aqueous fractions were filtered and the insoluble material dried under reduced pressure.…”

Chemistry and Synthesis of Highly Oxygenated Alkaloids from Amaryllidaceae: Lycoricidine, Narciclasine, Pancratistatin and Analogs

“…Diels-Alder cycloaddition has been proposed several times to construct the C-ring [10, [149][150][151][152][153]. A short report on the synthesis of an advanced intermediate toward lycoricidine based on the construction of the C-ring using a Diels-Alder approach and subsequent functionalization of the cyclohexene ring has been proposed by Mehta [154].…”

“…Iodolactonization was then achieved under carefully controlled conditions to give 215. It is interesting to note that such lactones have been prepared by Ohta [149] and Paulsen [141] in their…”