Regioselective A-Ring Chlorination of Benzodiazepine Analogues Using tert-Butyl Hypochlorite

Treatment of 2-phenyl-2,3-dihydro-1,4-benzodiazepin-5(4H)-one and a series of 1,4-benzoxazepinone analogues with tert-butyl hypochlorite affords products shown, by NMR and MS spectroscopy, to be chlorinated exclusively in the A-ring at positions 7 and/or 9.     

Regioselective Synthesis of Ellipticine

An eight‐step synthesis of the tetracyclic pyridocarbazole alkaloid ellipticine (= 5,11‐dimethyl‐6H‐pyrido[4,3‐b]carbazole; 1a ) in an overall yield of 13% is reported, starting from 4,7‐dimethyl‐1H‐indene. Key steps were iodination, Suzuki coupling, reductive cyclization, DDQ oxidation, and heterocyclization under loss of H₂O.     

Synthesis of Oxa-Steroidal-Estrogen Analogues

Antiestrogencompoundraloxifene(LY13948lHCI)'andphytoestrogencompoundipriflavone'arenewgenerationdrugsforthetreatmefltofosteoporosis.RaloxifeneisnowinphaseillclinicaltrialandipriflavonehasalreadybeendevelopedintoadrugforthemarketinJapanandinitaly.ThoughthechemicalstfUcturesofthesetWocompoundsaresimilartothatofestrogentoacertainextent,andthemechanismsoftheirboneprotectingeffectsareillternallyconnectedwiththatofestrogen,thefemalehormonicactionsandtheriskforuterineandbreastcancerofthesetwocompo…     

白藜芦醇类似物的合成

3,5-二甲氧基苄溴(4)与NaCN反应生成3,5-二甲氧基苄腈(5), 5经水解得到3,5-二甲氧基苯乙酸(6). 5与苯甲醛或取代苯甲醛发生Knoevenagel反应生成化合物2a～2d, 为Z式构型. 6与苯甲醛或取代苯甲醛发生Perkin反应得到化合物3a～3c, 为E式构型. 2a～2d和3a～3c均为白藜芦醇类似物. 给出了各步反应产物的IR, ¹H NMR, ¹³C NMR和MS数据, 讨论了影响反应的因素, 并给出了化合物2a～2d和3a～3c对乳腺癌细胞MCF-7、肺癌细胞H446、乳腺癌细胞231的体外生理活性和对正常肝细胞L02体外毒性的半致死浓度.     

Synthesis of Gossypol Analogues

Two gossypol analogues 2a and 2b were synthesized for biological evaluation as male contraceptive agents. The naphthol 8c was prepared by analogy with a known procedure starling from 3-isopropylcatechol ( 3 ). (t-Bu)₂O₂-Mediated phenolic coupling of 8c furnished the binaphthol 9c which, after pyrane ring closure, deprotection. and selective bisformylation with SnCl₄/Cl₂CHOCH₃, gave the target compound 2a . The corresponding tetrahydroxy analogue 2b was prepared in a similar way.     

西地那非类似物的合成

报道了一种合成西地那非类似物的新方法。以邻丙氧基苯甲酸为原料,经5步反应制得西地那非类似物的关键中间体--硫代西地那非氯{1-甲基-3-丙基-5-(2-丙氧基-5-氯磺酰苯基)-1,6-二氢-7H-吡唑并［4,3-d］嘧啶-7-硫酮}(7); 7与哌嗪衍生物反应合成了4个新型的西地那非类似物,收率72.3%~80.9%,纯度99.0%,其结构经¹H NMR和ESI-MS表征。     

茼蒿素类似物的合成

本文报道了天然昆虫拒食剂茼蒿素的一些新类似物的合成。整个工作以取代的呋喃丙醇为前体, 经间氯过氧苯甲酸氧化、Luche还原、双键环氧化、酸催化的螺环缩酮化以及自由基媒介的脱水反应给出目标产物。     

Synthesis of Tadalafil Analogues

Five novel compounds as potential phosphodiesterase type 5 (PDE‐5) inhibitors were synthesized from D‐tryptophan methyl ester via the Pictet–Spengler reaction and cyclization reaction. The structures of those compounds were confirmed by elemental analyses, IR, ¹H NMR, and ESI‐MS spectra.     

Regioselective Synthesis of N-Alkyl Pyridones

The regioselective synthesis of N-alkyl pyridones can be facilitated by alkylation of 2-methoxypyridines with activated halides. The syntheses are facile and high yielding with no traces of 2-alkoxypyridines.     

定位选择合成柠檬酸月桂醇单酯

定位选择合成柠檬酸月桂醇单酯;淀粉;催化氧化;胶粘性     

Synthesis Of Isomaltose Analogues

ABSTRACT

Preparation of the α-glucosides 11, 12, 13 and 14 were accomplished through glycosylation of racemic trans-1-hydroxy-2-(hydroxymethyl)cyclohexane using 2-thiopyridyl tetra-O-benzyl-glucoside as the glycosyl donor in acceptable overall yield for α-selectivity, but with poor regioselectivity. Glycosylation under thermodynamic control using tetrabenzyl glucopyranose acetate and trimethylsilyl triflate as the promotor gave similar results. The unprotected glucosides 12 and 13 were separated and characterized by NMR spectroscopy. Similarly methyl 4-deoxy-α-isomaltoside (5a) was prepared through halide catalyzed glycosylation of methyl 2,3-di-O-benzoyl-4-deoxy-α-D-glucopyranoside (15) in acceptable yield and the unprotected compound characterized by NMR spectroscopy. Compounds 5a, 12a, 13a and the mixture 11a and 14a were all tested as substrates for the enzyme glucoamylase from Aspergillus niger and proved to be very poor substrates for the enzymic hydrolysis.     

Synthesis of New Schizandrin Analogues

The lignans are groups of natural products, most of these compounds have various biological activities1. Such as schisandrin possesses extensive significant anti- convulsive activities, particularly regarding cerebral protection and adjustment of the cerebral cortex(s excitement inhibition process. Therefore, it is of interest to synthesize schzandrin and its analogues as potential CNS inhibitory agents. As a part of our drug discovery program for CNS inhibitory agents, we wanted to synthesi…     

Synthesis of Asymmetric Propanetriol Analogues

Form natural tartaric acid,(R)-2-benzyloxy-3-(2-tertrahydropyranyloxy) propanol 3 was designed and synthesized, and (R)-2-benzyloxy-3-(4-methoxybenzyloxy)propanol 7 was prepared in a new method. They can be used as chiral synthons of lysophosphatidic acid and other compounds with asymmetric propanetriol backbone.     

几丁寡糖结构类似物的化学合成

合成了两个结构新颖的几丁寡糖结构类似物: β-1,3连接的乙酰氨基葡聚二糖和β-1,3连接的乙酰氨基葡聚三糖, 并通过核磁共振和质谱分析确证了其化学结构. 与天然的几丁寡糖不同, 本文所合成的葡聚二糖和葡聚三糖均采取了1→3糖苷键的连接方式, 为研究几丁寡糖诱导植物抗病活性与寡糖区域异构体之间的关系提供有用材料.     

Synthesis of New Phosphomycin Analogues

Abstract

In the aim to carry out a quantitative reactivity/structure/biological activity relationship, a general four step synthesis, gives us access to a number of new phosphomycin analogues. A new synthesis of di- and tri-substituted vinylphosphonates via cuprate reactions and their epoxidation by dioxirane are described.     

Synthesis of Stable Dolichylphosphomannose Analogues

Four oleyl or dolichyl thiophosphate esters 16, 17, 21 , and 22 , analogues of Dol‐P‐Man possessing C(1)? S and/or P? S bonds, were synthesized as potential inhibitors of mannosyl transferases operating in the endoplasmic reticulum (ER). The β‐mannosyl derivatives were prepared by a Mitsunobu reaction of 2,3,4,6‐tetra‐O‐acetyl‐α‐D ‐mannopyranose ( 1 ) with the thiophosphate 2 that provided O‐ and S‐glycosides with good‐to‐excellent diastereoselectivity. A second route to β‐mannosyl derivatives is based on the phosphitylation of the β‐D ‐mannopyranosyl thiol 3 with the phosphoramidites 4a and 4b . Oxidation of the intermediate oleyl thiophosphite with t‐BuOOH led to mono‐ and dithiophosphates. The thiophospholipids 16, 21 , and 22 were inactive as inhibitors of the Man₆(GlcNAc)₂‐PP‐Dol glycolipid elongation.     

Regioselective Synthesis of 1,3,5-Trisubstituted Pyrazoles

Abstract

A new and a simple approach toward synthesis of 1,3,5-trisubstituted pyrazoles from chalcone arylhydrazones via oxidative cyclization has been achieved. 2,3-Dichloro-5,6-dicyano-1,4-benzoquinone was successfully used as an oxidizing agent to give excellent yields of pyrazoles.