Shulman-Roskes E M, Noe D A, Gamcsik M P, Marlow A L, Hilton J, Hausheer F H, Colvin O M, Ludeman S M
Johns Hopkins University School of Medicine, Baltimore, Maryland 21287, USA.
J Med Chem. 1998 Feb 12;41(4):515-29. doi: 10.1021/jm9704659.
NMR (1H and 31P) and HPLC techniques were used to study the partitioning of phosphoramide mustard (PM) and its aziridinium ions among alkylation and P-N bond hydrolysis reactions as a function of the concentration and strength of added nucleophiles at 37 degrees C and pH 7.4. With water as the nucleophile, bisalkylation accounted for only 10-13% of the product distribution given by PM. The remainder of the products resulted from P-N bond hydrolysis reactions. With 50 mM thiosulfate or 55-110 mM glutathione (GSH), bisalkylation by a strong nucleophile increased to 55-76%. The rest of the PM was lost to either HOH alkylation or P-N bond hydrolysis reactions. Strong experimental and theoretical evidence was obtained to support the hypothesis that the P-N bond scission observed at neutral pH does not occur in the parent PM to produce nornitrogen mustard; rather it is an aziridinium ion derived from PM which undergoes P-N bond hydrolysis to give chloroethylaziridine. In every buffer studied (bis-Tris, lutidine, triethanolamine, and Tris), the decomposition of PM (with and without GSH) gave rise to 31P NMR signals which could not be attributed to products of HOH or GSH alkylation or P-N bond hydrolysis. The intensities of these unidentified signals were dependent on the concentration of buffer.
采用核磁共振（1H和31P）及高效液相色谱技术，研究了在37℃和pH 7.4条件下，磷酰胺氮芥（PM）及其氮丙啶离子在烷基化反应和P-N键水解反应之间的分配情况，该分配情况是添加亲核试剂的浓度和强度的函数。以水作为亲核试剂时，双烷基化产物仅占PM给出的产物分布的10 - 13%。其余产物是由P-N键水解反应产生的。使用50 mM硫代硫酸盐或55 - 110 mM谷胱甘肽（GSH）时，强亲核试剂引起的双烷基化反应增加到55 - 76%。其余的PM则发生水合烷基化反应或P-N键水解反应。获得了强有力的实验和理论证据来支持以下假设：在中性pH下观察到的P-N键断裂并非发生在母体PM中以生成去甲氮芥；相反，是由PM衍生的氮丙啶离子发生P-N键水解生成氯乙基氮丙啶。在研究的每种缓冲液（双三羟甲基氨基甲烷、二甲基吡啶、三乙醇胺和三羟甲基氨基甲烷）中，PM（有或没有GSH）的分解都会产生31P NMR信号，这些信号不能归因于水合或GSH烷基化产物或P-N键水解产物。这些未识别信号的强度取决于缓冲液的浓度。
