(2S,3R)-1-二甲氨基-3-(3-甲氧基苯基)-2-甲基戊-3-醇的合成工艺研究

目的 对(2S,3R)- 1-二甲氨基-3-(3-甲氧基苯基)-2-甲基戊-3-醇合成工艺进行研究.方法 以3-戊酮为起始原料,经Mannich反应、手性拆分、Grignard反应等步骤合成(2S,3R)-1-二甲氨基-3-(3-甲氧基苯基)-2-甲基戊-3-醇,并对化学拆分进行工艺优化.结果 合成(2S,3R)-1-二甲氨基-3-(3-甲氧基苯基)-2-甲基戊-3-醇,总收率为30.6％.结论 工艺改进后提高了目标产物的收率,同时也减少了原料的浪费.     

(2R,3R,7Z)-2-Aminotetradec-7-ene-1,3-diol, a new amino alcohol from the caribbean sponge Haliclona vansoesti

The Caribbean marine sponge Haliclona vansoesti was found to contain a high amount (5% dry wt) of a new analogue of 4-sphingenine, (2R,3R, 7Z)-2-aminotetradec-7-ene-1,3-diol (1). Its structure was determined by detailed spectroscopic analysis. The relative configuration was deduced from the NMR data of the corresponding acetonide 5, while the absolute configuration was secured via protection of the primary alcohol and amino groups, and esterification of the secondary alcohol with Mosher's reagent.     

Antineoplastic agents 440. Asymmetric synthesis and evaluation of the combretastatin A-1 SAR probes (1S,2S)- and (1R,2R)-1, 2-dihydroxy- 1-(2',3'-dihydroxy-4'-methoxyphenyl)-2-(3' ',4' ',5' '-trimethoxyphenyl)-ethane

The synthetic (E)-isomer (3b) of natural combretastatin A-1 (1a) isolated from the African bushwillow Combretum caffrum was the focus of chiral hydroxylation (Sharpless) reactions as part of a structure-activity relationship study. The resulting (R,R)- and (S,S, )-diols (6 and 7) and synthetic intermediates were evaluated against a series of cancer cell lines, microorganisms, and tubulin. Chiral diols 6 and 7 showed increased activity against the P-388 murine lymphocytic leukemia cell line with ED(50) values of 3.9 and 2.9 microg/mL, respectively, when compared to the precursor (E)-stilbene 3b. In contrast, (E)-stilbene 3b exhibited more potent antibiotic activity than the chiral diols (6 and 7). Both diols, (R,R)-6 and (S, S)-7, displayed less cancer cell growth inhibition and less antibiotic activity than did natural combretastatin A-1 (1a) (P-388 ED(50) 0.25 microg/mL).     

CR377, a new pentaketide antifungal agent isolated from an endophytic fungus

Cultures of endophytic fungi collected in the Guanacaste Conservation Area of Costa Rica were screened for antifungal activity. CR377, a new pentaketide antifungal agent, was isolated from the culture broth of a fungus, CR377 (Fusarium sp.), that showed potent activity against Candida albicans in this assay. The structure of CR377 was established using 1- and 2-D NMR and HRFABMS.     

Synthesis of N-[(3S)-2,6-dioxo-1-(2-phenylethyl)-3-piperidinyl]-(2S)-2-methylbutanamide ((-)-julocrotine)

The total synthesis of (-)-julocrotine (1) starting from l-glutamic acid in 41% overall yield is described. The methodology utilizes protection, deprotection, and regioselection (carbonyl differentiation via oxazolidinone) protocols, and glutarimide ring formation is the key step.     

Expedient synthesis of (S)- and (R)-norcoclaurine from (S)- and (R)-norarmepavine [corrected] prepared by the 1-phenylethylurea method

(+/-)-Norarmepavine [3] [corrected] prepared by Bischler-Napieralski synthesis afforded, on reaction with (S)-(-)-1-phenylethylisocyanate, ureas 4 and 5 which were separated and purified by crystallization from EtOH and 70% HOAc. Alcoholysis of 4 and 5 with sodium butoxide in n-BuOH afforded (S)-norarmepavine [3a] and (R)-norarmepavine [3b] [corrected], respectively. Hplc analysis of ureas prepared from 3a and 3b with (S)-(-)-1-phenylethylisocyanate showed them to be optically pure alkaloids. Refluxing 3a and 3b with 48% HBr afforded the hydrobromide salts of (S)-norcoclaurine [1a] and its (R)-isomer 1b, respectively.     

Synthesis of (7S,15S)- and (7R,15S)-dolatrienoic acid

The stereospecific synthesis of (7S,15S)- and (7R,15S)-dolatrienoic acids (2) was achieved using an approach consisting of 16 linear steps. The C-11--C-16 unit was prepared in seven steps from ethyl (S)-lactate and coupled using a trans-selective Wittig--Schlosser reaction to the C-7--C-10 fragment. Chirality at the C-7 position was introduced using an Evan's-type chiral auxiliary in a cobalt-mediated Reformatsky reaction to give the (3S,11S)-aldehyde 24. Subsequent Wittig reaction with a phosphonium salt derived in three steps from tiglic acid gave (7S,15S)-dolatrienoic acid, one of the four possible diastereoisomers of the nonpeptide portion of the strong cancer cell growth inhibitory cyclodepsipeptide dolastatin 14 (1). A second diastereoisomer, (7R,15S)-dolatrienoic acid, was synthesized employing chiral oxazolidinone 21 by an analogous synthetic route.     

1,3-Dimethylguanine, a new purine from the new zealand ascidian botrylloides leachi

The new purine 1,3-dimethylguanine (1) has been isolated from the ascidian Botrylloides leachi. The structure of 1 was elucidated by analysis of spectroscopic data, by comparison with the regioisomeric purine 1,3-dimethylisoguanine (2), and by hydrolysis to theophylline (3).     

S(R)-podolactone D,a new sulfoxide-containing norditerpene dilactone from Podocarpus macrophyllus var. maki

S(R)()-Podolactone D (1), a new norditerpene dilactone having a methylsulfoxide moiety, was isolated from the leaves of Podocarpus macrophyllus D. Don var. maki Endl. along with known podolactone D (2, S(S)()-podolactone D). The structures and absolute configurations of compounds 1 and 2 were elucidated by spectral methods (HREIMS, IR, (1)H, (13)C, and 2D NMR) and finally confirmed by single-crystal X-ray analyses. The cytotoxic effects of compounds 1 and 2 on P388 murine leukemia cells were also examined.     

Partial synthesis of (3R,6'R)-alpha-cryptoxanthin and (3R)-beta-cryptoxanthin from (3R,3'R,6'R)-lutein

(3R,3'R,6'R)-Lutein (1), (3R,3'R)-zeaxanthin (2), (3R,6'R)-alpha-cryptoxanthin (3), and (3R)-beta-cryptoxanthin (4) are among dietary hydroxycarotenoids that have been identified in human serum, milk, and ocular tissues. While 1 containing 6% of 2 is commercially available, industrial production of optically active 3 and 4 has not yet been accomplished. Several processes have been developed that transform 1 into 3, 4, and minor quantities of (3R,5'RS,6'R)-3',4'-didehydro-5',6'-dihydro-beta,beta-caroten-3-ol (5) (a regioisomer of 3). In one process, lutein (1) was cleanly deoxygenated to 3 in the presence of trifluoroacetic acid (TFA) and Me3N.BH3 in CH2Cl2 at ambient temperature in nearly 90% yield. Reaction of lutein (1) with a Lewis acid (AlCl3, ZnBr2, ZnI2) and a hydride donor (Me3N.BH3, Na[BH3(OCOCF3)], NaCNBH3) in solvents such as CH2Cl2, THF, and TBME produced similar results. In a two-step process, high-temperature acid-catalyzed dehydration of 1 (propanol/water/acid, 90 degrees C) gave a mixture of anhydroluteins 6, 7, and 8 in 86% yield. In the second step, these dehydration products underwent ionic hydrogenation with TFA/Me3N.BH3 in CH2Cl2 to afford a mixture of 3 and 4 in nearly 80% yield that contained only 1% of 5.     

Stereoselective total synthesis of (3R,8S)-falcarindiol, a common polyacetylenic compound from umbellifers

The first stereoselective total synthesis of (3R,8S)-falcarindiol (1) from L-tartaric acid and D-xylose is reported, via the Cadiot-Chodkiczwicz reaction, to couple 1-bromoalkyne (2) with 3(R)-(tert-butyldiphenylsilyloxy)-1-penten-4-yne (3).     

Absolute configuration of a hydroxyfuranoid acid from the pelage of the genus Bos, 18-(6S,9R,10R)-bovidic acid

Pelage extracts of the banteng (Bos javanicus), the domestic cattle (B. taurus), the gaur (B. frontalis), and the yak (B. grunniens) were investigated by FABMS and NMR. An 18-carbon hydroxyfuranoid acid, 1 (10-hydroxy-6,9-oxidooctadecanoic acid), first reported from the wool of the domestic sheep (Ovis aries) was confirmed in B. frontalis; we suspend judgment on the occurrence of this compound in the other species we examined. The stereochemistry of 1, determined by Mosher NMR and CD tweezer methods, was assigned as 6S, 9R, 10R. We propose the name bovidic acid for this and homologous alpha-hydroxylated 2,5-tetrahydrofuranoid carboxylic acids, in reference to the family Bovidae, which represents their sole known natural source.     

(2S,3S)-sulfated pterosin C, a cytotoxic sesquiterpene from the Bangladeshi mangrove fern Acrostichum aureum

Two new sesquiterpenes, (2R,3S)-sulfated pterosin C (1) and (2S,3S)-sulfated pterosin C (2), along with two known derivatives, (2S,3S)-pterosin C and (2R)-pterosin P, were isolated from a methanolic extract of the aerial parts of Acrostichum aureum. The structures of 1 and 2 were determined by the interpretation of their spectroscopic data. The isolated pterosins were evaluated for their cytotoxic activity against the AGS, HT-29, MDA-MB-231, and MCF-7 human cancer cell lines and the NIH3T3 normal mouse fibroblast cell line, using the MTT assay. Compound 2 showed IC50 values in the range 23.9-68.8 μM. The lowest IC50 value (23.9 μM) was recorded against AGS gastric adenocarcinoma cells. Compound 2 was found to exert an apoptotic effect on AGS cells within 24 h of treatment, which increased with time and was greater than the positive control, cycloheximide. The cytotoxicity of 2 seems to be due in part to the sulfate group on C-14 and the configuration at C-2.     

Coproverdine,a novel,cytotoxic marine alkaloid from a new zealand ascidian

The crude extract of a New Zealand ascidian displayed antitumor activity. Bioassay-directed fractionation yielded a novel alkaloid, coproverdine (1). The structure of 1 was assigned on the basis of detailed spectroscopic analysis. Coproverdine (1) was responsible for the antitumor activity of the crude extract.     

特苄康唑对真菌麦角甾醇生物合成的影响

 目的：研究新化合物特苄康唑对真菌麦角甾醇生物合成的影响。方法：用薄层色说谱语扫描法考察真菌经不同浓度特苄康唑作用后,其麦角甾醇和羊毛甾醇的含量变化。结果：特苄康唑能使真菌中的麦角甾醇含量下降,羊毛甾醇含童增加,两者的 含量变化均有明显的剂量依赖性;同浓度时特苄康唑对真菌生长繁殖和麦角甾醇生物合成的抑制作用无显著差异。结论：特苄康唑是通过抑制真菌的麦角甾醇生物合成而发挥其高效抗真菌活性的,为羊毛甾醇14a-去甲基化酶抑制剂。     

Chiral dihydroxylation of acronycine: absolute configuration of natural cis-1,2-dihydroxy-1,2-dihydroacronycine and cytotoxicity of (1R,2R)- and (1S,2S)-1,2-diacetoxy-1,2-dihydroacronycine

Sharpless asymmetric dihydroxylation of acronycine (1) gave (1R, 2R)-1,2-dihydroxy-1,2-dihydroacronycine (2) and (1S,2S)-1, 2-dihydroxy-1,2-dihydroacronycine (3), which allowed determination of the absolute configuration of natural cis-1,2-dihydroxy-1, 2-dihydroacronycine as 1R,2R. The cis isomer had been previously isolated from various Sarcomelicope species. Benzylic reduction of isomers 2 and 3 gave the alcohols 4 (2R) and 5 (2S), respectively. Acetylation of 2 and 3 afforded the corresponding esters 6 and 7. No significant difference of cytotoxicity was observed between these (1R,2R)- and (1S,2S)-enantiomers and the recently described, highly active racemic cis-1,2-diacetoxy-1,2-dihydroacronycine, when tested against L-1210 cells in vitro.     

国产沉香中1个新的2-(2-苯乙基)色酮

目的对国产沉香的小极性化学成分进行研究。方法运用硅胶、Sephadex LH-20、半制备高效液相等色谱方法进行分离纯化,并根据理化性质和波谱数据鉴定化合物的结构。结果从国产沉香的石油醚提取物中分离得到4个2-(2-苯乙基)色酮衍生物,分别鉴定为6-甲氧基-7-羟基-2-(2-苯乙基)色酮(1)、6,7-二甲氧基-2-(苯乙基)色酮(2)、6,7-二甲氧基-2-[2-(4′-甲氧基苯)乙基]色酮(3)、6-甲氧基-2-[2-(3′-甲氧基-4′-羟基苯)乙基]色酮(4)。结论化合物1为新化合物,命名为沉香酮J;化合物4为首次从国产沉香中分离得到。     

An efficient conversion of (3R,3'R,6'R)-lutein to (3R,3'S,6'R)-lutein (3'-epilutein) and (3R,3'R)-zeaxanthin

Two dietary carotenoids, (3R,3'R,6'R)-lutein (1) and (3R,3'R)-zeaxanthin (2), and their metabolite (3R,3'S,6'R)-lutein (3'-epilutein) (3) accumulate in human serum, milk, and ocular tissues. There is increasing evidence that compounds 1 and 2 play an important role in the prevention of age-related macular degeneration. Therefore, the availability of these carotenoids for metabolic studies and clinical trials is essential. Compound 1 is isolated from extracts of marigold flowers (Tagete erecta) and is commercially available, whereas 2 is only accessible by a lengthy total synthesis, and a viable method for synthesis of 3 has not yet been developed. This report describes an efficient conversion of technical grade 1 to 2 via 3. Acid-catalyzed epimerization of 1 yields an equimolar mixture of diastereomers 1 and 3. The mixture was separated by enzyme-mediated acylation with lipase AK from Pseudomonas fluorescens that preferentially esterified 3 and after alkaline hydrolysis yielded this carotenoid in 90% diastereomeric excess (de). Compound 3 was also separated from 1 in 56-88% de by solvent extraction and low-temperature crystallization, Soxhlet extraction, or supercritical fluid extraction. Base-catalyzed isomerization of 3 gave 2 in excellent yield, providing a convenient alternative to the total synthesis of this important dietary carotenoid.     

罗替戈汀手性中间体S(-)2-(N-正丙基)胺基-5-甲氧基四氢萘的合成

目的 合成罗替戈汀关键手性中间体S(-)2-(N-正丙基)胺基-5-甲氧基四氢萘.方法 以5-甲氧基-2-四氢萘酮为起始物,经过正丙胺胺化、10％钯炭催化氢化还原、手性拆分3个步骤合成得到该中间体.结果手性中间体S(-)2-(N-正丙基)胺基-5-甲氧基四氢萘的总收率为21.5％.结论该路线的原料廉价易得、收率高,适合罗替戈汀的关键手性中间体S(-)2-(N-正丙基)胺基-5-甲氧基四氢萘的工业化生产.