Studies with alkylating esters. V. The reactions, metabolism and biological activities of some cyclic dimethanesulphonates; the relevance to the mechanism of action myleran

Four-component reaction leading to highly functionalized sulfoalkoxy carbonyl compounds

Four components together: a new paradigm of four component reaction brings α-bromo-β-sulfoalkoxyl carbonyl compounds with good stereocontrol in moderate to excellent yields.

Testicular endocrine effects of alkane methanesulphonates related to the Leydig cell cytotoxic compound, EDS

A series of compounds structurally similar to the specific Leydig-cell-cytotoxic substance ethane-1,2-dimethanesulphonate (EDS) were examined for Leydig cell toxicity in the rat. Within 48 h of a single injection of butane-2,3-dimethanesulphonate (BDS), propan-1,3-dimethanesulphonate (P-1,3-DS) or propan-1-chloro-2,3-DS (PCDS) there was a reduction in serum and testicular testosterone levels. The serum luteinizing hormone (LH) concentration was reduced following BDS or P-1,3-DS, and Leydig-cell LH receptors (measured by 125I-labelled hCG binding) were reduced by less than 15%, from which it is concluded that these compounds are not selectively toxic to Leydig cells. However, PCDS reduced human chorionic gonadotropin (hCG) binding by greater than 70% and could be considered to be a potential toxin. The effects of hydroxy-ethanemethane-sulphonate (HEMS), 1,5,2,4-dioxadithiepane-2,2,4,4-tetraoxide (cyclic SOSO), PCDS, propan-2,3-DS, alpha-chlorohydrin and cyclohexane-1,2-dimethane-sulphonate were compared with the effects of EDS 7 days after injection. Systemic toxicity, indicated by a loss of body weight, was associated with cyclic SOSO, PCDS and EDS, although only EDS and PCDS reduced both testicular hCG binding and serum and testis testosterone levels consistent with Leydig-cell toxicity. Further studies indicated that the potency of PCDS in reducing testicular hCG binding and serum and intratesticular testosterone levels was similar to that of EDS. However, unlike EDS, PCDS was systemically toxic and also reduced LH, which could at least in part account for changes in testosterone secretion. The experiments confirm the unique cytotoxicity of EDS. Loss of specific Leydig-cell cytotoxicity and an increase in systemic toxicity occurred when the EDS molecule was altered, even if the distance between the alkylating centres was maintained. The mechanism of action of EDS remains elusive.

Gas chromatographic assay for the new antitumor agent sulfamic acid diester (NSC 329680) and its stability in buffer, blood and plasma

A sensitive gas chromatographic assay with electron-capture detection has been developed for sulfamic acid diester (sulfamic acid 1,7-heptanediyl ester, NSC 329680) based on its conversion to 1,7-diiodoheptane in the presence of excess sodium iodide. The assay is linear up to 1 microgram/ml sulfamic acid diester and has a lower limit of detection of 25 ng/ml from 0.5 ml plasma. The coefficient of variation of the assay is 6.4% at 1 microgram/ml and 8.0% at 100 ng/ml. Sulfamic acid diester is relatively stable in 0.9% sodium chloride and 0.1 M sodium phosphate buffers, pH 7.0-9.0, with half-lives greater than 38 h. The major breakdown product of sulfamic acid diester is sulfamic acid 1,7-heptane-monoyl ester. When added to whole blood sulfamic acid diester shows concentration-dependent breakdown. At 50 and 100 micrograms/ml sulfamic acid diester, the half-time in whole blood is 6.9 h and 65% of the drug is sequestered by the blood cells. At 10 micrograms/ml sulfamic acid diester in blood, there is no detectable breakdown of the drug over 24 h and all of the drug is sequestered by the blood cells. Protein binding of sulfamic acid diester in human plasma is 82% at 10 micrograms/ml and 68% at 100 micrograms/ml.

Toxicological review of busulfan (Myleran)

Busulfan is a bifunctional alkylating agent that appears to be cytotoxic to slowly proliferating or non-proliferating stem cell compartments, although its specific molecular and cellular mechanisms are unknown. It is the drug of preference in treatment of chronic myelogenous or granulocytic leukemia because its cytotoxic activity results in primary damage or destruction of hematopoietic cells. Additional effects resulting from the cytotoxicity of busulfan in hematological and other tissues, as documented by both human and animal model studies, include lethality, sterility, teratogenicity, and alteration of immune function. Busulfan has been shown to be mutagenic to microorganisms, mammalian cells in culture, Drosophila, and rodents. This agent is also considered potentially carcinogenic to humans. Various tissue hyperplasia and preneoplastic cells have been observed in animal model studies with busulfan, and case reports on human patients implicate busulfan as the causative agent in induction of secondary malignancies. Reports from human and animal studies of busulfan's cytotoxicity, teratogenicity, carcinogenicity, and mutagenicity have been reviewed. This information may be useful in a quantitative assessment of the effects of this agent and the identification of significant deficiencies in the data base. Demonstration that busulfan induces mutations in both somatic and germ cells suggests the need to assess its risk to humans.

Alkylating esters. X. The reaction of some aziridine alkylating agents with methionine and S-methyl cysteine

Two biologically active aziridine ring-containing compounds, N,N-ethylene urethane (I) and N,N-ethylene urea (II), have been shown to react with methionine in dilute phosphate buffer (pH 7.4) at 37 degree C. Degradative procedures indicate that the aziridine ring effectively alylates the thio ether group of methionine and other thio ether-containing amino acids to produce sulphonium salts (V). By using [35S]methionine, the sulphonium salts have been shown to be quite stable under physiological conditions (t1/2 7--9 days) hydrolysing to convert the methionine residue to homoserine. It is proposed that similar alkylations of methionyl residues in vivo by aziridine-alkylating agents may explain the complex, and al yet unknwn, metabolic fate of the aziridine ring and could also be a factor contributing to the diverse effects that these agents have on living cells.