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BioAssay: AID 233500

The pKa value was measured at 31-P chemical shift changes due to protonation

The chemistry of the bifunctional alkylating agent phosphoramide mustard and model phosphoramides was probed by multinuclear NMR spectroscopy as a function of pH. Between pH 1 and 11, both the 31P and 15N resonances for phosphoramide mustard displayed a single monobasic titration curve with a pKa of 4.9. The protonation below pH 4.9 correlates with the loss in reactivity of the mustard. The 17O more ..
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 Tested Compounds
 Tested Compounds
All(9)
 
 
Unspecified(9)
 
 
 Tested Substances
 Tested Substances
All(9)
 
 
Unspecified(9)
 
 
 Related BioAssays
 Related BioAssays
AID: 233500
Data Source: ChEMBL (230857)
Depositor Category: Literature, Extracted
BioAssay Version:
Deposit Date: 2010-05-21
Modify Date: 2014-05-19

Data Table ( Complete ):           All
Tested Compounds:
Description:
Title: Protonation of phosphoramide mustard and other phosphoramides.

Abstract: The chemistry of the bifunctional alkylating agent phosphoramide mustard and model phosphoramides was probed by multinuclear NMR spectroscopy as a function of pH. Between pH 1 and 11, both the 31P and 15N resonances for phosphoramide mustard displayed a single monobasic titration curve with a pKa of 4.9. The protonation below pH 4.9 correlates with the loss in reactivity of the mustard. The 17O NMR spectrum of 17O-enriched phosphoramide mustard shows little change with pH. The data on the mustard was compared to 15N and 31P NMR data on 15N-enriched phosphoramidic acid, phosphorodiamidic acid, and phosphoric triamide. Contrary to the conclusions of previous studies, our combined 31P, 15N, and 17O NMR results are more consistent with N-protonation of phosphoramide mustard rather than an O-protonation. Theoretical calculations on the phosphoramidic acid, phosphorodiamidic acid, and phosphoric triamide show O-protonation to be more stable in the gas phase. For the latter two compounds, the calculations suggest that N-protonation may be the most stable protonated form in the aqueous phase. These findings influence our understanding of the structure-activity relationships of phosphoramide mustards.
(PMID: 8246232)
Comment
Putative Target:

ChEMBL Target ID: 22226
Target Type: UNCHECKED
Pref Name: Unchecked
Confidence: Default value - Target unknown or has yet to be assigned
Relationship Type: Default value - Target has yet to be curated
Categorized Comment
Assay Type: Binding

Assay Data Source: Scientific Literature

Result Definitions
TIDNameDescriptionHistogramTypeUnit
OutcomeThe BioAssay activity outcomeOutcome
1pKa activity commentpKa activity commentString
2pKa standard flagpKa standard flagInteger
3pKa qualifierpKa qualifierString
4pKa published valuepKa published valueFloat
5pKa standard valuepKa standard valueFloat

Data Table (Concise)
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