Synthesis of 14-epi-19-nor-22-oxa-1α,25-dihydroxyvitamin D3

The synthesis of 14-epi-19-nor-22-oxa-1α,25(OH)2D3 5 was started from diol 8 via Fall's method, oxidation, epimerization, protection, coupling with the 19-nor-A-ring 7, and then deprotection of the hydroxyl functions.     

Synthesis of 14-epi-19-nor-22-oxa-1α,25-dihydroxyvitamin D3

The synthesis of 14-epi-19-nor-22-oxa-1α,25（OH）2D3 5 was started from diol 8 via Fall＇s method, oxidation, epimerization, protection, coupling with the 19-nor-A-ring 7, and then deprotection of the hydroxyl functions.     

The Synthesis of 19-Nor-1α, 25-dihydroxy-22-oxo-vitamin D_3

Since the last decade, there has been a growing interest in the development of analogues of 1(, 25- dihydroxyvitamin D3 1 with low calcemic effect but increased cell differentiating ability1. Among side chain and the A-ring modifications of 1, the 1(, 25- dihydroxy-22-oxo-vitamin D3 22 and 19-nor-1(, 25- dihydroxyvitamin D3 33 have shown much lower calcemic effect and stronger cell differentiating ability than 1. In this paper, we reported synthesis of 19-nor-1(, 25-dihydroxy-22-oxo-vitamin …     

The Synthesis of an Optically Active Intermediate of A-Ring for 1α,25-Dihydroxy Vitamin D_3 Analogs

Asla,25-dihydr0xyvitaminD31,thehorm0nallyactiveformofvitandnD3incalciumhomoeostasis,caninducecelIdifferentiationandinhibitcellproliferation',thesynthesis0f1anditsanalogshaveattfactedmuchinterestz-.Recently,TrostandHanson5havereportedabrilliantstrategyf0rthesynthesis0f1,whichemploysacyclizationofthel,7-enyne3aandthevinylbr0mide2as0utlinedinScheme1.However,theysynthesizedthekeyintermediate4a,startingfromethyl4-chloroacetoacetatewhichhasalowstereoselectivityandisanexpensivereagent.Inthispaper,w…     

19-失碳-1α, 25-二羟基维生素D~3A环合成子的合成

报道以价廉、易得的D-(-)-奎尼酸为手性源,经9步反应,有效地合成光学活性的19-失碳-1α,25-二羟基维生素D~3A环合成子4的合成方法。     

Efficient Synthesis of 2—Ethyl—A—ring Analogues of 19—Nor—1α,25—dihydroxy Vitamin D3

The novel 19-nor-1α,25-dihydroxy vitamin D3 analogues possessing an ethyl at the 2-position(4 and 5).were synthesized by coupling 25-hydroxy Windaus-Grundmann ketone derivative 20 with A-ring synthons(15 and 19)respectively.The enantioselective synthesis of substituted bicyclic[3,1,0]hexanes structure A-ring synthons,started from all-cis-3,5-dihydroxy-4-ethyl-1-(methoxycarbonyl)cyclohexane via lipase-catalyzd asymmetrization,was demonstratcd.     

Enantioselective synthesis of A key A-ring intermediate for the preparation of 1α,25-dihydroxyvitamin D(3)

A novel approach to the key A-ring α, β-unsaturated aldehyde 1, an important intermediate for the preparation of 1α,25-dihydroxyvitamin D(3), has been developed. The strategy started from the inexpensive starting material (R)-carvone with an ene reaction serving as the key step toward the potential synthesis of vitamin D(3) analogues bearing the modification at the C-2 position.     

13α-取代-去-C-环-19-去亚甲基-1α,25-二羟基维生素D_3类似物的合成

以维生素D3为起始原料,经臭氧化,Baeyer-Villiger氧化内酯化,开裂六元环,二氧化钌(RuO2)引进C-25位羟基,最后经Horner-Wittig反应偶合D环和A环得到13-取代-去-C-环-19-去亚甲基-1α,25-二羟基维生素D3类似物(12a,12b).     

New method in synthesizing an optical active intermediate for （R,R）-formoterol

（R）-1-（4-Methoxyphenyl）propan-2-amine 2a, an optical active intermediate for （R,R）-formoterol, was synthesized from Dalanine in 65% overall yield by using a simple route, which contained protecting amino group, cyclization, coupling with Grignard reagent, reduction and deprotection.     

Stereochemistry Control in Direct 1α-Hydroxylation of 5,6-trans-Vitamin D3 by Solid Support

1α-Hydroxyvitamin D3 1 (1α-hydroxycholecalciferol) is a biologically active form ofvitamin D3 2 which exhibits a much broader spectrum of biological activities thanvitamin D3 . 1,2 Recently a number of analogues have been found to have specificenhanceme…     

Synthesis of 1, 4-Bis[3-N-propionyl-2-aryl-1, 3, 4- oxadiazoline-5-yl]phenylenes

1, 3, 4-Oxadiazoline derivatives are found to possess significant biological activities such as antifungal1, insecticidal2, CNS depressant3-5, anticonvulsant effects and plant growth accelerator. They are highly important heterocycles, and have been used …     

(1S,6R)-1-羟基-6-(1,3-苯并二硫-2-氧)-3,5-环维生素D2的合成

以VD2为原料制备了1α，25－二羟基维生素D3的重要中间体（1S，6R）－1－羟基－6－（1，3－苯并二硫－2－氧）－3，5－环维生素D2。其中BDT（1，3－苯并二硫－2－氧）基团的引入有利于共轭三烯系统的保护。     

Synthesis of Hymecromone Derivatives Containing Chiral 1,1＇-Bi-2-naphthyl Moiety for Dual-mode Molecular Switch

Some hymecromone derivatives containing chiral 1,1‘-bi-2-naphthyl moiety were synthesized and their photodimerizations were investigated. It was found that fluorescence intensity and optical rotation of the new chiral hymecromone derivatives could be regulated by light.This property has potential significance for developing a new type of dual-mode molecular switch.     

Synthesis of 24-Methylene-cholest-5-ene-7-oxo-3β,19-diacetate

24-Methylenecholest-5-ene-7-oxo-3β,19-diacetate 5 was synthesized starting from stigmasterol via twelve step reactions in 4.1% overall yield. It can be served as a key intermediate for the synthesis of 24-methylenecholest-5-ene-3β,7β,19-mol 1, a naturally occuring polyhydroxylated sterol with potential biological activity.     

A Facile Stereospecific Synthesis of 1, 3-Enynylsulfides via Sonogashira Coupling of （E）-a-Iodovinyl Sulfides with 1-Alkynes

（E）-α-Iodovinyl sulfides 1 underwent the Sonogashira coupling reactions with terminal alkynes 2 in piperidine at room temperature in the presence of 5 mol % of Pd（PPh3）4 and 10 mol % of CuI to afford the corresponding 1, 3-enynylsulfides 3 stereospecifically in high yields.     

Synthesis and Biological Evaluation of Novel 1, 5-Diarylpyrazole-3-carboxamide Compounds as Inhibitors of ALK5

Many diaryl or triaryl substituted imidazoles and triazoles are known to be selective inhibitors of transforming growth factor β1(TGF-β1) type 1 receptor (ALK5)1-3. SB-431542, one of the leading compound of 2-pyridyl substituted triarylimidazole, is an …     

Synthesis of C-Nucleoside Analogues： 2-[2-（Hydroxymethyl）-1, 3-dioxolan-5-yl]1, 3-thiazole-4-carboxamide and 2-[2-（Mercaptometh-yl）-1, 3-dioxolan-5-yl] 1, 3-thiazole-4-carboxamide

Novel C-nucleosides of tiazofurin analogue (2-[2-(hydroxymethyl)-1,3-dioxolan-5-yl] 1,3-thiazole-4-carboxamide) and its thiol-substituted derivative (2-[2-(mercaptomethyl)-1,3-dioxolan-5-yl] 1, 3-thiazole-4-carboxamide) were synthesized from methyl acrylate through a multistep procedure. Their structures were confirmed by IR, ^1HNMR, ^13CNMR and elemental analysis.     

Synthesis of （3aS,6aR）- 1,3-Dibenzyl-tetrahydro- 1H-thieno[3,4-d]-imidazole-2（3H）-one-4-ylidenepentanoic Acid and Characterization of Its Crystal

1 INTRODUCTION The title compound, (3aS,6aR)-1.3-dibenzyl- tetrahydro-1H-thieno[3,4-d]-imidazole-2(3H)-one- 4-ylidenepentanoic acid 3, is a key intermediate for the synthesis of d-biotin 1 (VITH, Fig. 1) which has been widely used not only as a pharmaceu…     

Design and Synthesis of 3, 4-Dihydropyrrolo[2, 1-c][1, 4]oxazin-l-one and its 7-Acyl Derivatives

Starting from 1H-pyrrole, unreported 3, 4-dihydropyrrolo[2, 1-c][1, 4]oxazin-1-one 4, 7-(4-chlorobenzoyl)-3, 4-dihydropyrrolo[2, 1-c][1, 4]oxazin-1-one 5 and 7-benzoyl-3, 4-dihydro-pyrrolo [2, 1-c][1, 4]oxazin-1-one 9 were designed and synthesized. They may have antipyretic and analgesic activities.