Synthesis of N-(4-aminobenzoyl)-γ-oligo (L-glutamic acid)s*

N-(4-aminobenzoyl)-γ-oligo (l -glutamic acid)s (6) containing from two to six glutamic residues have been prepared in solution using Nα-Boc-α-Bzl protections and isobutyl-chlorocarbonate activation. Key steps in the synthesis were the coupling of γ-oligo(α-benzyl l -glutamate) benzyl esters (1) with N-(4-benzyl-oxycarbonylaminobenzoyl)-l -glutamic acid α-benzyl ester (4) to blocked precursors of N-(4-aminobenzoyl)-γ-oligo (l -glutamic acid)s (5) and catalytic hydrogenolysis of 5 to 6. Elaboration of the required oligo γ-l -glutamate chains (1) was achieved step by step beginning with the coupling of glutamic acid dibenzylester with N-(t-butoxycarbonyl)-l -glutamic acid α-benzyl ester (2) to 3 followed by selective removal of the Boc from 3 with HCl-dioxane followed by coupling with 2.     

N-芳乙基异喹啉衍生物的合成及其抗肿瘤活性研究

本研究采用一种简便的新方法设计合成了一系列全新结构的N-芳乙基异喹啉衍生物, 并对其体外抗肿瘤活性进行了评价。其中化合物9a表现出较强的抗肿瘤活性, 对人肝癌HepG2和大肠癌HCT116细胞的IC₅₀值分别为2.52和1.99 μg·mL^–1。初步作用机制显示, 9a可以将HepG2细胞周期阻滞于S期, 使细胞增殖受阻, 达到抗肿瘤效果。     

Brain uptake and CNS levels of 1-(2-chloroethyl)-1-nitroso-3-(2-hydroxyethyl)urea (HECNU)

The uptake of ¹⁴C-labeled 1-(2-chloroethyl)-1-nitroso-3-(2-hydroxyethyl) urea (HECNU) into the brain was investigated in the rat after intracarotid injection according to the method of OLDENDORF, as well as in cisternal cerebrospinal fluid obtained by suboccipital puncture after i.v. injection of the drug.The brain uptake index was 31.9 ± 2.9%. Cerebrospinal fluid/blood quotients after i.v. injection were 0.82 at 10 min and 1.10 at 60 min. The results of both methods clearly show that HECNU, in spite of its hydrophilic property, easily penetrates the blood-brain barrier.     

2-取代亚胺基-3-[N-(2-氯乙基)]氨甲酰四氢噻唑的合成及其抗肿瘤活性研究

本文通过2-氯乙基异氰酸酯与各种N-取代-2-氨基-2-噻唑啉反应合成了十三个未见文献报道的2-取代亚胺基-3-[N-(2-氯乙基)]氨甲酰四氢噻唑化合物,其结构均经~1HNMR,IR、MS等得到证实。初步药效表明:2-苄基亚胺基-3-(N-(2-氯乙基)]氨甲酰四氢噻唑(2)对小白鼠爱氏腹水癌(EAC)有较高的抑制率(60.5％)。     

Stereoselective monooxygenation of carcinostatic 1-(2-chloroethyl)-3-(cyclohexyl)-1-nitrosourea and 1-(2-chloroethyl)-3-(trans-4-methylcyclohexyl)-1-nitrosourea by purified cytochrome P-450 isozymes

Three highly purified forms of liver microsomal cytochrome P-450 (P-450a, P-450b and P-450c) from Aroclor 1254-treated rats catalyzed 1-(2-chloroethyl)-3-(cyclohexyl)-1-nitrosourea (CCNU) and 1-(2-chloroethyl)-3-(trans-4-methylcyclohexyl)-1-nitrosourea (MeCCNU) monooxygenation in the presence of purified NADPH-cytochrome P-450 reductase, NADPH, and lipid. Differences in the regioselectivity of CCNU and MeCCNU monohydroxylation reactions by the cytochrome P-450 isozymes were observed. Cytochrome P-450-dependent monooxygenation of CCNU gave only alicyclic hydroxylation products, but monooxygenation of MeCCNU gave alicyclic hydroxylation products, an αhydroxylation product on the 2-chloroethyl moiety, and a trans-4-hydroxymethyl product. A high degree of stereoselectivity for hydroxylation of CCNU and MeCCNU at the cis-4 position of the cyclohexyl ring was demonstrated. All three cytochrome P-450 isozymes were stereoselective in primarily forming the metabolite cis-4-hydroxy-trans-4-Methyl-CCNU from MeCCNU. The principal metabolite of CCNU which resulted from cytochromes P-450a and P-450b catalysis was cis-4-hydroxy CCNU, whereas the principal metabolites from cytochrome P-450c catalysis were the trans-3-hydroxy and the cis-4-hydroxy isomers. Total amounts of CCNU and MeCCNU hydroxylation with cytochrome P-450b were twice that with hepatic microsomes from Aroclor 1254-treated rats. Catalysis with cytochromes P-450a and P-450c was substantially less effective than that observed with either cytochrome P-450b or hepatic microsomes from Aroclor 1254-treated rats.     

Cyclic melanotropins

The highly potent cyclic analogue of α-MSH, Ac-[Cys⁴, Cys¹⁰]-α-MSH_4–13-NH₂, was structurally modified in position 4. Four analogues were prepared and their biological activities in the in vitro frog and lizard skin bioassays were determined. It was shown that removing the terminal acetylamino group to give [Mpa⁴, Cys¹⁰]-α-MSH_4–13-NH₂ resulted in little change in the biological activity, but a change in the stereochemistry of cysteine in position 4 to give Ac-[D-Cys⁴, Cys¹⁰]-α-MSH_4–13-NH₂ led to a small decrease of activity in both bioassays. Decreasing the size of the intramolecular ring by removing one methylene group to give [Maa⁴, Cys¹⁰]-α-MSH_4–13-NH², resulted in an analogue with lower activities in both assays (about 3 times in the lizard and 500 times in the frog), and increasing the size of the ring by one methylene group to give Ac-[Hcy⁴, Cys¹⁰]-α-MSH_4–13-NH₂ led to much lower activities in the lizard system and similar effects were seen upon decreasing the ring size in the frog skin assay.     

N-(3-甲基-1-吡咯烷基)-1-丁酮基-苯丙酰胺的合成研究

目的:合成心血管疾病新治疗靶点小分子白介素1受体/髓样分化蛋白88-TIR(Toll/IL-1receptor)(IL-1R/MyD88-TIR)拟似物N-(3-甲基-1-吡咯烷基)-1-丁酮基-苯丙酰胺。方法:以N-叔丁氧羰基-L-缬氨酸羟基琥珀酰亚胺酯为原料,先合成3-甲基-2-叔丁氧羰氨基-1-吡咯烷基-1-丁酮,再合成N-(3-甲基-1-吡咯烷基)-1-丁酮基-苯丙酰胺,产物结构经核磁共振(NMR)和质谱(MS)确证。结果:通过2步反应合成了N-(3-甲基-1-吡咯烷基)-1-丁酮基-苯丙酰胺,反应总收率为81.1%,产物结构经NMR和MS证实为目标化合物。结论:该反应条件温和,操作方便,收率较高。     

Synthesis and solubility properties of peptide fragments of human hemoglobin α-chain (123-136)

The solubility prediction method for protected peptides was successfully applied to relatively small peptide fragments of human hemoglobin α-chain (123-136) which contained various polar amino acid residues such as Asp(OBzl), Glu(OBzl), Lys(Z), Ser(Bzl), and Thr(Bzl). As reported previously for hydrophobic peptides and human proinsulin C-peptide fragments, solubility data indicated that the insolubility of protected peptides having a <P_C > value below 0.90 appeared to begin at the octa- or nonapeptide sequence level and that β-sheet structure played an important role in the insolubility of peptides. When a peptide has a β-sheet structure in the solid state, we can clearly determine the critical chain length for peptide insolubility, the solubility dependence on solvent properties, and the solubility independence of amino acid compositions of peptides.     

The preferred solid-state conformation of (αMe)Trp peptides

The two Z-l -Ala-d l -(xMe)Trp-NH₂ diastereomeric dipeptides were synthesized from (Z-l -Ala)₂O and H-dl -(xMe)Trp-NH₂. The latter racemate, prepared by phase-transfer catalyzed alkylation of the N^α-benzylidene derivative of alanine amide followed by acidic hydrolysis of the resulting Schiff base, was characterized by X-ray diffraction. The molecular and crystal structure of Z-l -Ala-l -(αMe)Trp-NH², separated from its diastereomer by silica-gel column chromatography, was determined by X-ray diffraction analysis. Both independent molecules in the asymmetric unit of the dipeptide adopt a type-II β-bend conformation. However, only the more regularly folded conformation of molecule B is stabilized by a 1←4 C=O…H—N intramolecular H bond. The present results indicate that: (i) the Cα-methylated (αMe)Trp residue is a strong β-bend and helix former, and (ii) the relationship between (αMe)Trp chirality and helix screw sense tends to be opposite to that of protein amino acids. The implications for the use of the (αMe)Trp residue in designing conformationally restricted analogs of bioactive peptides are briefly discussed. ©Munksgaard 1995.     

Synthesis and in vitro anti-HIV Activity of Certain 2-(1H-Benzimidazol-2-ylamino)pyrimidin-4(3H)-ones and Related Derivatives

In an ongoing effort to develop novel non-nucleoside human immunodeficiency virus inhibitors, a series of substituted 2-(1H-benzimidazol-2-ylamino)pyrimidin-4(3H)-ones and related derivatives were synthesized via cyclocondensation of 2-guanidino-1H-benzimidazole with diethyl ethoxymethylenemalonate, substituted diethyl malonates, some β-keto esters and 2-acetylbutyrolactone. From these series of compounds, 2-(1H-benzimidazol-2-ylamino)-6-hydroxy-5-phenylpyrimidin-4(3H)-ones ( 5f , NSC 666286) was confirmed to have a moderate in vitro anti-HIV activity.     

N-(3-甲基-1-吡咯烷基)-1-丁酮基-乙酰胺的合成研究

以BOC-L-缬氨酸羟基琥珀酰亚胺酯为原料,两步反应合成IL-1R/MyD88-TIR拟似物N-(3-甲基-1-吡咯烷基)-1-丁酮基-乙酰胺,该反应条件温和,操作方便,收率较高,产物结构经NMR和MS得到了确证.     

Study of frog (Rana esculenta) proopiomelanocortin processing in the intermediate pituitary Identification of α-melanotropin, β-melanotropin,Lys-γ-melanotropin,and corticotropin-like intermediate lobe peptide

The proteolytic processing of frog (Ranu esculenta) proopiomelanocortin in melanotropic cells of the intermediate pituitary gland has been examined through purification of the mature fragments by reverse-phase high-pressure liquid chromatography and microsequencing of isolated peptides. α-Melanotropin, β-melanotropin, Lys-γ-melanotropin, corticotropin-like intermediate lobe peptide, and hinge peptide have been isolated and chemically characterized. The results show a high preservation in the processing sites of frog proopiomelanotropin when compared to bovine counterparts. They reveal also a great conservation of the processing enzyme equipment of melanotropic cells in tetrapods species. Identification of Lys-γ-melanotropin suggests the occurrence of an endopeptidase able to cleave between two basic residues. On the other hand α-melanotropin does not appear to be N-acetylated, as previously found in the clawed-toad Xenopus laevis, and this feature might distinguish amphibian from mammalian proopiomelanocortin processing.     

N-(2-巯基吡啶-3-甲酰)-N-烃基甘氨酸及其双硫化合物的合成

肾素—血管紧张素系统在调节人体血压时有重要作用。当此系统机能亢进时,会引起血压上升。血管紧张素转化酶(ACE)抑制剂既能对该系统有调节作用,又能抑制有降压作用的缓激肽分解,而起到降血压的效应。此外,它对充血性心力衰竭也有良好疗效。新近报道,ACE抑制剂尚有抗心绞痛作用。     

N-(顺式-4-异丙基环己基-1-甲酰基)-D-苯丙氨酸和N-(反式-4-异丙基环己基-1-甲酰基)-L-苯丙氨酸的合成

目的合成N-(顺式-4-异丙基环己基-1-甲酰基)-D-苯丙氨酸和N-(反式-4-异丙基环己基-1-甲酰基)-L-苯丙氨酸.方法以(4-异丙基)环己基甲酸为原料,在二环己基碳二亚胺(DCC)作用下,与N-羟基琥珀酰亚胺反应得到(4-异丙基)环己基甲酸琥珀酰亚胺酯(3),柱色谱分离化合物3得到顺式和反式异构体.顺式体与D-苯丙氨酸甲酯发生酰化反应,碱水解后即得到N-(顺式-4-异丙基环己基-1-甲酰)-D-苯丙氨酸;而反式体与L-苯丙氨酸甲酯发生酰化反应,水解后得到N-(反式-4-异丙基环己基-1-甲酰)-L-苯丙氨酸.结果与讨论成功合成了目标化合物,反应总收率分别为39%和31%.     

β-LIPOTROPIN: PRIMARY STRUCTURE OF THE HORMONE FROM THE OSTRICH PITUITARY GLAND

The amino acid sequence of β-lipotropin from the ostrich pituitary has been determined. It consists of 79 amino acids. The amino acid 10sequence has been determined as follows: H-20Ala-Leu-Pro-Pro-Ala-Ala-Met-Leu-Pro-Ala-30Ala-Ala-Glu-Glu-Glu-Glu-Gly-Glu-Glu-Glu-40Glu-Glu-Gly-Glu-Ala-Glu-Lys-Glu-Asp-Gly-50Gly-Ser-Tyr-Arg-Met-A rg-His-Phe-Arg-Trp-Gln-60Ala-Pro-Leu-Lys-Asp-Lys-Arg-Tyr-Gly-Gly-70Phe-Met-Ser-Ser-Glu-Arg-Gly-Arg-Ala-79Pro-Leu-Val-Thr-Leu-Phe-Lys-Asn-Ala-Ile-Val-Lys-Ser-Ala-Tyr-Lys-Lys-Gly-Gln-OH. When compared with the primary structures of other known β-lipotropins, the sequence at the NH₂-terminal, β-melanotropin and β-endorphin portions of the molecule exhibit considerable variability.     

Synthesis and anticancer evaluation of N-benzoyl-N'-phenyltiourea derivatives against human breast cancer cells (T47D)

New anti-breast cancer compounds have been found and may prove to have stronger activity. To predict the activities of N-benzoyl-N'-phenylthiourea (BPTU) derivatives, namely N-(3-chloro)benzoyl-N'-phenylthiourea (3-Cl-BPTU) and N-(3,4-dichloro)benzoyl-N'-phenylthiourea (3,4-2Cl-BPTU) with Sirtuin-1 receptor (PDB code: 4I5I), molecular docking was conducted at the beginning of this study. The compounds were then synthesized from benzoyl chloride derivatives and N-phenylthiourea. Molecular structure was confirmed using FTIR, ¹H NMR, ¹³C NMR and Mass Spectra, while the anticancer activity was tested in vitro against human breast cancer cells (T47D) using MTT assay. The results indicated that the anti-cancer activities of the test compounds were better than those of the hydroxyurea as the reference compound, evidenced by the Rerank Score (RS). Furthermore, cytotoxic effect of 3-Cl-BPTU (IC₅₀: 0.43 mM) and 3,4-dichloro-BPTU (IC₅₀: 0.85 mM) showed better result compared with hydroxyurea (IC₅₀: 4.58 mM). Therefore, we concluded that these compounds could possess termendous potential as the candidate for a new anticancer drug.     

The Proteolytic Stability and Cytotoxicity Studies of l‐Aspartic Acid and l‐Diaminopropionic Acid derived β‐Peptides and a Mixed α/β‐Peptide

The use of peptides as drugs in pharmaceutical applications is hindered by their susceptibility to proteolysis and therefore low bioavailability. β‐Peptides that contain an additional methylene group in the backbone, are gaining recognition from a pharmaceutical stand point as they are considerably more resilient to proteolysis and metabolism. Recently, we reported two new classes of β ‐peptides, β ³‐ and β²‐peptides derived from l ‐aspartic acid and l ‐diaminopropionic acid, respectively. Here, we report the proteolytic stability of these β‐peptidic compounds and a mixed α /β‐peptide against three enzymes (pronase, trypsin and elastase), as well as, human serum. The stability of these peptides was compared to an α‐peptide. Peptides containing β‐linkages were resistant to all conditions. The mixed α /β‐peptide, however, exhibited proteolysis in the presence of trypsin and pronase but not elastase. The rate of degradation of the mixed α /β‐peptide was slower than that would be expected for an α‐peptide. In addition, these β‐peptides were not toxic to HeLa and COS‐1 cell lines as observed by MTT cytotoxicity assay. These results expand the scope of mixed α /β‐peptides containing β‐amino acids or small β‐peptide fragments as therapeutic peptides.     

Crystallographic characterization of conformation of 1-aminocyclopropane-1-carboxylic acid residue (Ac3c) in simple derivatives and peptides*

The molecular and crystal structures of the C^α,α-dialkylated α-amino acid residue 1-aminocyclopropane-1-carboxylic acid hemihydrate (H₂^⊕-Ac₃c-O^?·½ H₂O) and nine derivatives and dipeptides have been determined by X-ray diffraction. The derivatives are pBrBz-Ac₃c-OH, Piv-Ac₃c-OH, Z-Ac₃c-OH, the α- and β-forms of t-Boc-Ac₃c-OH, Z-Ac₃c-OMe, and the 5(4H)-oxazolone from pBrBz-Ac₃c-OH; the dipeptides are H-(Ac₃c)₂-OMe and c(Ac₃c)₂. The values determined for the torsion angles about the N-C^α (φ) and C^α-C′ (φ) bonds for the single Ac₃c residue of Piv-Ac₃c-OH, the α- and β-forms of t-Boc-Ac₃-OH and Z-Ac₃c-OMe, and the C-terminal Ac₃c residue of H-(Ac₃c)₂-OMe correspond to folded conformations in the “bridge” region of the Ramachandran map. The structures of pBrBz-Ac₃c-OH and Z-Ac₃c-OH, however, are unusual in having a semi-extended conformation for the φ,ψ angles. The N-terminal Ac₃c residue of H-(Ac₃c)₂-OMe adopts a novel type of C₅ conformation, characterized inter alia by an (amino) N ? H-N (peptide) intramolecular hydrogen bond. While the acyl N^α-blocking groups form trans amides (pBrBz-Ac₃c-OH and Piv-Ac₃c-OH), the urethane groups may adopt either the trans [Z-Ac₃c-OH and t-Boc-Ac₃c-OH(α-form)] or the cis amide conformations [t-Boc-Ac₃c-OH(β-form) and Z-Ac₃c-OMe]. The five- and six-membered rings of the 5(4H)-oxazolone and the 2,5-dioxopiperazine, respectively, are planar. The four independent molecules in the asymmetric unit of the free α-amino acid are zwitterionic.     

In vitro pharmacokinetics and pharmacodynamics of 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU)

The relationship between treatment efficacy and the pharmacokinetics (PK) and pharmacodynamics (PD) of anticancer drugs is poorly defined. 1,3-Bis(2-chloroethyl)-1-nitrosourea (BCNU) is an alkylating agent used in the treatment of brain and other forms of cancer. It is postulated that BCNU kills cells by forming DNA interstrand cross-links. The present study was undertaken to characterize the PK and PD of BCNU in mouse L1210 cells. L1210 cells were exposed to BCNU (0-160 microM) and analyzed for intracellular BCNU concentrations, DNA interstrand cross-links, cell cycle phase, and cytotoxicity. The half-life of BCNU in cells was approximately 40 min. The maximum reduction of mitochondrial enzyme activity (maximum cell death) achieved within 24 hr after exposure to BCNU was concentration-dependent and could be described by a Hill equation. At lower concentrations, the area under the DNA interstrand cross-link-time curve linearly correlated with the maximum cell death and the area under the BCNU concentration-time curve. BCNU induced cell accumulation in the G(2)/M phase of the cell cycle, which continued even after apparent completion of cross-link repair. Loss of membrane permeability was minimal (approximately 2%) during the first 24 hr. Thereafter, cells died exponentially over the next 9 days, primarily by necrosis. In conclusion, while cytotoxicity was concentration-dependent, an indirect relationship was found among the time-course of BCNU concentrations, DNA interstrand cross-links, and cell death. Because of the disparity between the time-scale of PK and PD, focusing only on the early events may provide limited information about the process of anticancer drug-induced cell death.     

N-[2-(4-特戊酰氧基苯磺酰胺基)苯甲酰基]甘氨酸苄酯的合成

目的合成西维来司钠（sivelestat sodium）的关键中间体N—[2-（4-特戊酰氧基苯磺酰胺基）苯甲酰基]甘氨酸苄酯（1）。方法先以特戊酸、氯化亚砜、对羟基苯磺酸为原料，经酯化、苯磺酸成酰氯得到对位特戊酰氧基苯磺酰氯（4）；再以甘氨酸、苄醇、邻硝基苯甲酰氯为原料经酯化、酰氨化、还原得到N-（2-氨基苯甲酰基）甘氨酸苄酯（7）；将4和7两中间体缩合得1。结果及结论本方法原料廉价易得，条件温和易控，收率较高，适合工业化生产。