Lawesson's Reagent

• Catalog No.: A14530
• CAS Number: 19172-47-5
• M. F.: C14H14O2P2S4
• M. W.: 404.467282
• Purity: 97%

SYNONYMS

• Title: 劳氏试剂
• IUPAC name: bis(4-methoxyphenyl)-1,3,2λ^5,4λ^5-dithiadiphosphetane-2,4-dithione
• IUPAC Traditional name: lawesson's reagent
• Synonyms: 4-Methoxyphenylthionophosphine sulfide dimer; 2,4-Bis(4-methoxyphenyl)-2,4-dithioxo-1,3,2,4-dithiadiphosphetane

DATABASE IDS

• CAS Number: 19172-47-5
• Beilstein Number: 1024888
• EC Number: 242-855-4
• MDL Number: MFCD00005171
• Merck Index: 145391

PROPERTIES

• Purity: 97%
• Melting Point: 221-225°C
• GHS Hazard statements: H331-H302-H315-H319-H335-H261
• European Hazard Symbols: X
• European Hazard Symbols: Flammable (F)
• GHS Precautionary statements: P231+P232-P305+P351+P338-P302+P352-P321-P405-P501A
• Risk Statements: 15/29-20/22-36/37/38
• Safety Statements: 7/8-9-26-33-36/37-43
• Storage Warning: Moisture Sensitive
• TSCA Listed: 是
• Hazard Class: 4.3
• UN Number: UN3134
• Packing Group: III

REFERENCES

• Powerful thionation agent used for the replacement of the carbonyl oxygen of ketones, amides and esters, by sulfur: Bull. Soc. Chim. Belg., 87, 223, 229, 293, 299, 525 (1978); Tetrahedron, 35, 1339, 2433 (1979). Review: Tetrahedron, 41, 5061 (1985). For conversion of N-methylpyrrolidinone to the thiolactam, see: Org. Synth. Coll., 7, 372 (1990).
• Uracil and its derivatives are thionated selectively at the 4-position: Synthesis, 152 (1988). Peptides give endo-thiopeptides: Tetrahedron, 37, 3635 (1981). Esters, orthoesters, acetals and epoxides give the thio-analogues: Monatsh. Chem., 115, 769 (1984). Used, in combination with 1,1,3,3-Tetramethylthiourea, L13392, for formation of bis-thioesters for subsequent radical coupling as a method of ring formation in Nicolaou's syntheses of hemibrevitoxin B and brevitoxin B: J. Am. Chem. Soc., 115, 3558 (1993); 117, 10227 (1995).
• Reaction with 1,4-diketones gives 2,5-disubstituted thiophenes in high yield: Synthesis, 1061 (1982).
• Reaction with ɑ-diazo ketones has been used to prepare 1,2,3-thiadiazoles: Heterocycles, 19, 241 (1982).
• Benzylic and related alcoholsare converted to the corresponding thiols: J. Chem. Soc., Chem. Commun., 205 (1989); J. Chem. Soc., Perkin 1, 1113 (1993).
• Reacts with N-protected amino acids to give mixed anhydrides, useful in peptide coupling: Tetrahedron, 38, 3267 (1982). See Appendix 6.
• Has also been found to act as an efficient trapping agent for 1,3-dipoles under very mild conditions. Its powerful dipolarophile character allows it to be used as a "1,3-dipole indicator" even with dipoles of low reactivity, the outcome of the reaction being readily verified by ³¹P NMR: J. Org. Chem., 60, 3904 (1995).