Mechanism of dansylation of the polyamine pentaazapentacosane ·5 HCl

Susan Heimbecher; Yung Chi Lee; S. Esmail Tabibi; Samuel H. Yalkowsky

doi:10.1016/S0378-5173(97)00315-3

Mechanism of dansylation of the polyamine pentaazapentacosane ·5 HCl

Susan Heimbecher, Yung Chi Lee, S. Esmail Tabibi, Samuel H. Yalkowsky

Pharmacology and Toxicology

Research output: Contribution to journal › Article › peer-review

1 Scopus citations

Abstract

Dansylation of the pentaamine pentaazapentacosane ·5 HCl (PAPC) produces only the perdansyl product. This occurs even under conditions of pH and dansyl chloride concentration most likely to produce partially dansylated products. This result is explained by a mechanism whereby only completely unionized amine molecules will dansylate. The proposed mechanism is supported by the dansylation versus pH profile of PAPC versus that of a reference monoamine (piperidine ·HCl). After 4 h at room temperature and pH 9.5, 100% of piperidine is dansylated while under the same conditions only 10% of PAPC is derivatized. A pH greater than 10.5 is required to completely dansylate PAPC. This difference is significantly greater than would be predicted from the pK(a) values but it is consistent with the proposed mechanism.

Original language	English (US)
Pages (from-to)	21-29
Number of pages	9
Journal	International Journal of Pharmaceutics
Volume	160
Issue number	1
DOIs	https://doi.org/10.1016/S0378-5173(97)00315-3
State	Published - Jan 12 1998

Keywords

Dansyl chloride
Dansylation
Pentaazapentacosane pentahydrochloride
Polyamines

ASJC Scopus subject areas

Pharmaceutical Science

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10.1016/S0378-5173(97)00315-3

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title = "Mechanism of dansylation of the polyamine pentaazapentacosane ·5 HCl",

abstract = "Dansylation of the pentaamine pentaazapentacosane ·5 HCl (PAPC) produces only the perdansyl product. This occurs even under conditions of pH and dansyl chloride concentration most likely to produce partially dansylated products. This result is explained by a mechanism whereby only completely unionized amine molecules will dansylate. The proposed mechanism is supported by the dansylation versus pH profile of PAPC versus that of a reference monoamine (piperidine ·HCl). After 4 h at room temperature and pH 9.5, 100% of piperidine is dansylated while under the same conditions only 10% of PAPC is derivatized. A pH greater than 10.5 is required to completely dansylate PAPC. This difference is significantly greater than would be predicted from the pK(a) values but it is consistent with the proposed mechanism.",

keywords = "Dansyl chloride, Dansylation, Pentaazapentacosane pentahydrochloride, Polyamines",

author = "Susan Heimbecher and Lee, {Yung Chi} and Tabibi, {S. Esmail} and Yalkowsky, {Samuel H.}",

note = "Funding Information: We would like to thank Dr M.F. Burke for his critical comments. This work was performed under the National Cancer Institute Contract # N01-CM-27757.",

year = "1998",

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AU - Heimbecher, Susan

AU - Lee, Yung Chi

AU - Tabibi, S. Esmail

AU - Yalkowsky, Samuel H.

N1 - Funding Information: We would like to thank Dr M.F. Burke for his critical comments. This work was performed under the National Cancer Institute Contract # N01-CM-27757.

PY - 1998/1/12

Y1 - 1998/1/12

N2 - Dansylation of the pentaamine pentaazapentacosane ·5 HCl (PAPC) produces only the perdansyl product. This occurs even under conditions of pH and dansyl chloride concentration most likely to produce partially dansylated products. This result is explained by a mechanism whereby only completely unionized amine molecules will dansylate. The proposed mechanism is supported by the dansylation versus pH profile of PAPC versus that of a reference monoamine (piperidine ·HCl). After 4 h at room temperature and pH 9.5, 100% of piperidine is dansylated while under the same conditions only 10% of PAPC is derivatized. A pH greater than 10.5 is required to completely dansylate PAPC. This difference is significantly greater than would be predicted from the pK(a) values but it is consistent with the proposed mechanism.

AB - Dansylation of the pentaamine pentaazapentacosane ·5 HCl (PAPC) produces only the perdansyl product. This occurs even under conditions of pH and dansyl chloride concentration most likely to produce partially dansylated products. This result is explained by a mechanism whereby only completely unionized amine molecules will dansylate. The proposed mechanism is supported by the dansylation versus pH profile of PAPC versus that of a reference monoamine (piperidine ·HCl). After 4 h at room temperature and pH 9.5, 100% of piperidine is dansylated while under the same conditions only 10% of PAPC is derivatized. A pH greater than 10.5 is required to completely dansylate PAPC. This difference is significantly greater than would be predicted from the pK(a) values but it is consistent with the proposed mechanism.

KW - Dansyl chloride

KW - Dansylation

KW - Pentaazapentacosane pentahydrochloride

KW - Polyamines

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Mechanism of dansylation of the polyamine pentaazapentacosane ·5 HCl

Abstract

Keywords

ASJC Scopus subject areas

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