A novel structure of sinomenine isoxazole derivatives is synthesized from sinomenine hydrochloride and aromatic aldehydes and requires 6 steps. 19 target compounds have been obtained in good yields. The sinomenine hydrochloride transforms to 4-alkynyl sinomenine, which is a key intermediate product to synthesize the target sinomenine isoxazole compounds, after a neutralization reaction with ammonia and substitution reaction with 3-chloropropyne. Another key intermediate product is 1,3-dipole, which can be obtained from aromatic aldehyde. After treatment with hydroxylamine hydrochloride and then sodium carbonate solution, aromatic aldehyde is converted to aldehyde oxime, which reacts with N-chlorosuccinimide (NCS) to afford aryl hydroximino chloride. 1,3-dipole is eventually formed in situ while triethylamine (TEA) in DMF is added dropwise. Then 4-alkynyl sinomenine is added to provide the sinomenine isoxazole derivative via 1,3-dipolar cycloaddition reaction as the key step. All the target compounds are characterized by melting point,

The synthesis of C-ring hydrogenated sinomenine derivatives is accomplished from sinomenine by treatment with Zn-Hg/HCl, halogenation with NIS, and Heck reactions with various acrylates. A total of nine novel sinomenine cinnamate derivatives are obtained in 84%–93% yields. The structures of all the derivatives are characterized by 1H NMR, 13C NMR, and MS spectroscopy.

The synthesis of C-ring quinoxaline-substituted sinomenine 1,2,3-triazole derivatives at the 4-OH via click reactions is accomplished, and a total of 16 novel sinomenine double N-heterocyclic derivatives are obtained in 74%–95% yields. The C-ring is first transformed into a 1,2-diketone structure under the action of hydrochloric acid, and then reacted with o-phenylenediamine to obtain a C-ring quinoxaline-substituted structure. The 4-OH of sinomenine reacts with chloropropyne to give an alkynyl sinomenine, and then reacts with sodium azide and various benzyl chlorides to give the target compounds. All the synthesized derivatives are characterized by Fourier-transform infrared spectrometry, high resolution mass spectrometry, 1H NMR, and 13C NMR spectroscopy.

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