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26412-87-3 - Sulfur trioxide-pyridine complex, 98%, active SO3 ca 48-50% - Pyridine-sulfur trioxide complex - A12202 - Alfa Aesar

A12202 Sulfur trioxide-pyridine complex, 98%, active SO3 ca 48-50%

CAS Number
Pyridine-sulfur trioxide complex

Size Price ($) Quantity Availability
10g 19.50
50g 44.60
250g 188.00
1000g 516.00
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Sulfur trioxide-pyridine complex, 98%, active SO3 ca 48-50%


Chemical Properties

Formula Weight
Melting point
ca 155-165°
Moisture Sensitive
Soluble in polar organic solvents.


Sulfur trioxide-pyridine complex is used for sulfations of alcohols, sulfonations, deoxygenations and other reductions, oxidations with dimethyl sulfoxide. It is also used as a source of sulfur trioxide especially in the preparation of sulfate esters. Further, it is used as an activating electrophile in a Parikh-Doering oxidation. In addition to this, it is also used in the preparation and anticoagulation test of sulfated silk fibroin.


Moisture sensitive. Incompatible with strong oxidizing agents.

Literature References

Converts alcohols to monoalkyl sulfates, utilized in carbohydrate protection: Carbohydr. Res., 127, 211, 131, C8 (1984); J. Org. Chem., 38, 3510 (1973). The pyridinium sulfates of allylic or benzylic alcohols can be deoxygenated in high yields by in situ LiAlH4 reduction in THF: J. Org. Chem., 34, 3667 (1969); Tetrahedron Lett., 4650 (1972); J. Am. Chem. Soc., 93, 7016 (1971).

Sulfonates indole at the 3-position: Tetrahedron, 29, 669 (1973).

The combination with Dimethyl­ sulfoxide, A13280, is a mild oxidant for alcohols to carbonyl compounds (Parikh-Doering Reagent): J. Am. Chem. Soc., 89, 5505 (1967), avoiding the very low temperatures required for the Swern and similar systems (see Oxalyl­ chloride, A18012). With chiral alcohols, less racemization occurs at the ɑ-carbon than with Collins' reagent or pyridinium dichromate: Tetrahedron Lett., 23, 807 (1982); J. Org. Chem., 46, 4799 (1981). Nicolaou utilized the system at 0oC to convert an epoxy alcohol to the corresponding aldehyde in the synthesis of hemibrevitoxin B: J. Am. Chem. Soc., 115, 3558 (1993).

In combination with NaI, reduces ɑ-halo ketones to ketones: Synthesis, 59 (1979), and sulfoxides to sulfides: Synthesis, 984 (1979).

Lim, D. K.; Wylie, R. G.; Langer, R.; Kohane, D. S. Selective binding of C-6 OH sulfated hyaluronic acid to the angiogenic isoform of VEGF165. Biomaterials 2016, 77, 130-138.

Sarbova, V.; Koschella, A.; Cheng, F.; Kelly, S. M.; Heinze, T. Studies on the sulfation of cellulose alpha-lipoate and ability of the sulfated product to stabilize colloidal suspensions of gold nanoparticles. Carbohydr. Polym. 2015, 124, 117-123.

GHS Hazard and Precautionary Statements

Hazard Statements: H302-H314-H318

Harmful if swallowed. Causes severe skin burns and eye damage. Causes serious eye damage.

Precautionary Statements: P260u-P303+P361+P353-P305+P351+P338-P301+P330+P331-P405-P501a

Do not breathe dusts or mists. IF ON SKIN (or hair): Remove/Take off immediately all contaminated clothing. Rinse skin with water/shower. IF IN EYES: Rinse cautiously with water for several minutes. Remove contact lenses, if present and easy to do. Continue rinsing. IF SWALLOWED: Rinse mouth. Do NOT induce vomiting. Store locked up. Dispose of contents/container in accordance with local/regional/national/international regulations.

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