Article · Wikipedia archive · Last revised Aug 8, 2026

BOP reagent

BOP (benzotriazol-1-yloxytris(dimethylamino)phosphonium hexafluorophosphate) is a reagent commonly used for the synthesis of amides from carboxylic acids and amines in peptide synthesis. It can be prepared from 1-hydroxybenzotriazole and a chlorophosphonium reagent under basic conditions. This reagent has advantages in peptide synthesis since it avoids side reactions like the dehydration of asparagine or glutamine residues. BOP has used for the synthesis of esters from the carboxylic acids and alcohols. BOP has also been used in the reduction of carboxylic acids to primary alcohols with sodium borohydride (NaBH4). Its use raises safety concerns since the carcinogenic compound HMPA is produced as a stoichiometric by-product.

Last revised
Aug 8, 2026
Read time
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Citations
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Source
Wikipedia ↗
BOP reagent
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Names
IUPAC name
((1H-Benzo[d][1,2,3]triazol-1-yl)oxy)tris(dimethylamino)phosphonium hexafluorophosphate(V)
Other names
Castro's reagent
Identifiers
3D model (JSmol)
ChemSpider
ECHA InfoCard 100.054.782
UNII
  • InChI=1S/C12H22N6OP.F6P/c1-15(2)20(16(3)4,17(5)6)19-18-12-10-8-7-9-11(12)13-14-18;1-7(2,3,4,5)6/h7-10H,1-6H3;/q+1;-1 checkY
    Key: MGEVGECQZUIPSV-UHFFFAOYSA-N checkY
  • F[P-](F)(F)(F)(F)F.n1nn(O[P+](N(C)C)(N(C)C)N(C)C)c2ccccc12
Properties
C12H22F6N6OP2
Molar mass 442.287 g/mol
Appearance White crystalline powder
Melting point 136 to 140 °C (277 to 284 °F; 409 to 413 K)
Partially soluble in cold water reacts (decomposes)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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BOP (benzotriazol-1-yloxytris(dimethylamino)phosphonium hexafluorophosphate) is a reagent commonly used for the synthesis of amides from carboxylic acids and amines in peptide synthesis.12 It can be prepared from 1-hydroxybenzotriazole and a chlorophosphonium reagent under basic conditions.3 This reagent has advantages in peptide synthesis since it avoids side reactions like the dehydration of asparagine or glutamine residues.4 BOP has used for the synthesis of esters from the carboxylic acids and alcohols.5 BOP has also been used in the reduction of carboxylic acids to primary alcohols with sodium borohydride (NaBH4).6 Its use raises safety concerns since the carcinogenic compound HMPA is produced as a stoichiometric by-product.

See also

See also

  • PyBOP, a related phosphonium reagent for amide bond formation
  • PyAOP, a related phosphonium reagent for amide bond formation
References

References

  1. "(Benzotriazol-1-yloxy)tris(dimethylamino)phosphonium hexafluorophosphate 226084". BOP Reagent. Retrieved 2020-02-11.
  2. Mansour, Tarek S.; Bardhan, Sujata; Wan, Zhao-Kui (2010). "Phosphonium- and Benzotriazolyloxy-Mediated Bond-Forming Reactions and Their Synthetic Applications". Synlett. 2010 (8): 1143–1169. doi:10.1055/s-0029-1219820. ISSN 0936-5214.
  3. Hoffmann, Frank; Jäger, Lothar; Griehl, Carola (2003-02-01). "Synthesis and Chemical Constitution of Diphenoxyphosphoryl Derivatives and Phosphonium Salts as Coupling Reagents for Peptide Segment Condensation". Phosphorus, Sulfur, and Silicon and the Related Elements. 178 (2): 299–309. doi:10.1080/10426500307942. ISSN 1042-6507.
  4. Prasad, KVSRG; Bharathi, K; Haseena, Banu B (2011). "Applications of Peptide Coupling Reagents- An Update" (PDF). International Journal of Pharmaceutical Sciences Review and Research. 8 (1): 108–119.
  5. Kim, Moon H.; Patel, Dinesh V. (1994-08-01). ""BOP" as a reagent for mild and efficient preparation of esters". Tetrahedron Letters. 35 (31): 5603–5606. doi:10.1016/S0040-4039(00)77257-1. ISSN 0040-4039.
  6. McGeary, Ross P. (1998). "Facile and chemoselective reduction of carboxylic acids to alcohols using BOP reagent and sodium borohydride". Tetrahedron Letters. 39 (20): 3319–3322. doi:10.1016/S0040-4039(98)00480-8. ISSN 0040-4039.