Thionation of Tryptanthrin, Rutaecarpine, and Related Molecules with a Reagent Prepared from P₄S₁₀ and Pyridine

Abstract

Reaction of P4S10 in hot pyridine produces a crystalline solid which can be collected and used for thionations in other solvents such as acetonitrile and sulfolane. The biologically active natural products tryptanthrine, rutaecarpine, 7,8-dehydrorutaecarpine, and some related compounds have now been converted to thionated versions simply by heating the molecules with this thionating reagent in sulfolane (typically at 135 °C for 20 min) followed by a workup in water. No chromatography was necessary.

Dihydroxyquingdainone Induces Apoptosis in Leukaemia and Lymphoma Cells via the Mitochondrial Pathway in a Bcl-2- and Caspase-3-Dependent Manner and Overcomes Resistance to Cytostatic Drugs In Vitro

“…Since it was insoluble in basic aqueous media, it is suspected not to be an ionic molecule, while there is a difference in its solubility in methanol or acetone. Bergman also reports some stable thioketones of tryptanthrin and ditryptanthrin, prepared by oxygen–sulphur exchange [ 9 ]. Regarding the idea that such an exchange might have been feasible with thioxothiazolidinone on tryptanthrin, its absolute insolubility in everything disproves such an idea.…”

Comparison of Two Reagents for Thionations

“…The energy required to remove one or two of the pyridine ligands from reagent 4 is notable at the temperature 120-180 °C (Scheme 8), and 4 dissolved in sulfolane, which has several uses in industry, 30 is a powerful thionation reagent in the temperature range 120-170 °C. 31…”

Open-Circuit Photovoltage Exceeding 950 mV with an 840 mV Average at Sb2S3–Thianthrene+/0Junctions Enabled by Thioperylene Anhydride Back Contacts

“…Thionation reagents included Lawesson’s reagent (LR), 35 P 4 S 10 , 36 and a P 4 S 10 –pyridine complex 37 that each convert C=O to C=S. 38 − 41 X-ray photoelectron spectroscopy (XPS) verified thionation and the presence or absence of reagent contaminants on surfaces. Nonaqueous photoelectrochemistry of Sb 2 S 3 deposited on surfaces 1 – 3 , 5 – 6 , and thiol-terminated control surface 7 in thianthrene +/0 correlated the relationship between the chemical structure of the back contact and the subsequent open-circuit photovoltage, V oc , under illumination.…”

“…We explored the thionation of a perylene-anhydride-terminated surface 3 and of a diethyl-ester-terminated surface 4 with a series of thionation reagents that, respectively, yield a thioperylene-anhydride-terminated surface 5 or a di­(ethyl thionoester)-terminated surface 6 . Thionation reagents included Lawesson’s reagent (LR), P 4 S 10 , and a P 4 S 10 –pyridine complex that each convert CO to CS. − X-ray photoelectron spectroscopy (XPS) verified thionation and the presence or absence of reagent contaminants on surfaces. Nonaqueous photoelectrochemistry of Sb 2 S 3 deposited on surfaces 1 – 3 , 5 – 6 , and thiol-terminated control surface 7 in thianthrene +/0 correlated the relationship between the chemical structure of the back contact and the subsequent open-circuit photovoltage, V oc , under illumination.…”