Simple and Effective Synthetic Approach to Chiral 2-Amino-4-piperidinyl Pyridine Derivatives

A facile way has been developed to provide a series of novel chiral N-(4-(piperidin-1-yl)pyridin-2-yl)amide derivatives as potential stereoselective catalysts. The key intermediate, 2-amino-4-piperidinyl pyridine, was obtained by nucleophilic substitution of 2-amino-4-chloropyridine with piperidine in good yields (up to 96%). The total control of enantioselectivity was obtained for the synthesis of L-proline and (R)-1,1′-bi(2-naphthol) derivatives.     

Improved Synthetic Approach to Tenatoprazole

An improved synthetic approach to tenatoprazole 1 is described. It started from 2,3,5‐trimethyl‐4‐nitropyridine‐N‐oxide 2 with acetic anhydride via rearrangement and hydrolysis to give 3, Chlorination with SOCl₂ yielded 2‐chloromethyl‐3,5‐dimethyl‐4‐nitropyridine hydrochloride 4, then 4 condensed with 2‐mercapto‐5‐methoxy imidazole [4,5‐b]pyridine 5 to give 5‐methoxy‐2‐[(4‐nitro‐3,5‐dimethyl‐2‐pyridinyl)methylthio]imidazole[4,5‐b]pyridine 6. At last the title compound 1 was produced by two methods: 6 was oxidized with MCPBA and then methoxylated with CH₃ONa to give 1 and 6 was first methoxylated with CH₃ONa and then oxidized with MCPBA to give 1. The overall yield is around 26% for both five‐step syntheses.     

Synthetic Approach to 4a-Methyltetrahydrofluorene-Type Diterpenoids via an Aromatic Oxidation of Phenol Derivatives

An intramolecular aromatic oxidation of a phenolic compound with a hypervalent iodine reagent afforded the coupling product, in which the coupling took place at the para-position of the methoxy goup of the starting material instead of the desired para-position of the isopropenyl group, unfortunately.      

A Simple One-Pot Procedure for the Direct Conversion of Alcohols to Azides via Phosphate Activation

A one-pot procedure was developed to prepare efficiently alkyl azides from alkanols using bis(2,4-dichlorophenyl) phosphate activation. 4-(Dimethylamino)pyridine was used as a base, and phosphorylpyridinium azide is believed to be the activating agent under this condition.     

A Simple Approach to Azoieues

Recently, we demonstrated that the reaction of certain 2-phenylbicyclo-[1.1.0]butanes with rhoium dicrbonyl chloride dimer produced dihydroazulenes, which, on oxidation, were converted to azulenes.³. The utility of this process for the preparation of azulene derivatives was limited by the availability of the phenyl substituted bicyclo[1.1.0]butanes. Although the C-H insertion reaction, developed by Moore and coworkers⁴ for the preparation of 2-phenylbicyelo[1.1.0]butanes from dibromocyclopropanes, works very well, the required absence of cyclopropyl hydrogans, and the problems inherent in the preparation of the hexasubstituted dibromocyclopropane intermediates made the overall synthesis of azulenes by this route rather tedious. We now wish to report a simplified approach to the synthesis of azulenes whis has as one of the critical steps, the transition metal complex promoted rearrangement of a 2-phenylbicyclo[1.1.0]butane.     

A Synthetic Approach to Homologous Blockcopolymers

Summary: Blockcopolymers of 3-methyl-3-phenylcyclopropene and norbornene derivatives were synthesized via ROMP. The crossover reaction during ROMP blockcopolymerization was successfully monitored via MALDI-TOF MS in agreement with GPC and NMR-methods.     

Novel Synthetic Approach to Multibenzoylated Nucleosides

An improved and highly efficient synthetic approach to multibenzoylated nucleosides bearing free 5′‐hydroxyl groups is described here. By employing t-butyldimethylsilyl (TBDMS) rather than the more commonly used dimethoxytrityl (DMTr) as a temporary 5′‐OH protecting group of the starting nucleoside, this methodology provides the expected products in nearly quantitative yields, thereby substantially reducing the cost and effort of synthesis.     

异黄酮类化合物的合成新方法

提出了一种新颖的合成异黄酮类化合物1, 2和3的方法. 以1,3-二甲氧基苯或1,3,5-三甲氧基苯为原料, 经Hoesch反应或Friedel-Crafts酰化反应、脱甲基反应、增碳关环一系列反应得到关键的甲氧基异黄酮化合物, 然后甲氧基异黄酮经过不同浓度氢溴酸的选择性水解反应制得含一个或多个羟基的异黄酮类化合物.     

New Synthetic Approach to Polyfluorinated Carbonates

Russian Journal of Organic Chemistry - Transesterification of commercial titanium(IV) alkoxides with 2,2,3,3-tetrafluoropropan-1-ol, followed by in situ transesterification of mixed titanium(IV)...     

A Complementary Synthetic Approach to Fluorazone

Pyrrole undergoes a regioselective zinc‐mediated acylation with 2‐bromobenzoyl chloride followed by a Cu‐catalyzed N‐arylation under microwave irradiation, delivering the important heteroaromatic of fluorazone.     

A New Synthetic Approach to Salmeterol

In the present work a short and convenient route for the synthesis of salmeterol from salicylaldehyde has been developed.     

A New Synthetic Approach to Elvucitabine

A new synthetic approach to elvucitabine started from L-xylose via the reactions of 10 steps in an overall yield of 20% was developed. The key steps included trimethylsilyl trifluoromethanesulfonate(TMSOTf)-mediated stereocontrolled β-glycosidation and exquisite choice of chloroacetyl group for the protection of hydroxyl groups as well as the corresponding deprotection under notably mild conditions. The structure of elvucitabine, in particular, the stereochemistry thereof, was unambiguously determined by comparison of the physical properties, such as ¹H NMR data and the specific rotation, of the synthesized sample with those reported.     

茶螺烷酮合成的新工艺

以α-紫罗兰酮为原料,经间氯过氧苯甲酸环氧化、甲醇钠开环、超声波辐射Pd/C催化甲酸铵选择性碳碳双键加H、硼氢化钠还原、脱水环化及乙酰丙酮亚钴催化烯丙位氧气氧化等6步反应,以总收率52.6％合成了食用香料2,6,10,10-四甲基-1-氧杂-螺[4.5]-6-癸烯-8-酮(茶螺烷酮)。 用IR、1H NMR、MS谱及元素分析等测试技术表征了产物的结构和组成。     

A Facile Synthetic Approach to Two Chalcones

Some Vitex species have long been used in folk remedies due to their excellent antibiotic activities1. Chalcones also have good activities such as immunological action2. 2? 4?dihydroxy-4, 6?dimethoxy chalcone 1 and 4?hydroxy-4, 2? 6?trimethoxy chalcone 2 were natural products which were firstly separated from the aerial parts of Vitex leptobotrys in North Vietnam by Trinh3. To our knowledge, no synthetic method about these compounds was reported. Herein we report a convenient synthetic r…     

A New Synthetic Approach to Coumestan Derivatives

A new method for the preparation of coumestan derivatives was described involving an intramolecular palladium‐catalyzed ring closure reaction of coumarins obtained from condensation of substituted o‐hydroxyphenylacetic add and o‐hydroxybenzaldehyde.     

A Novel Synthetic Approach to Phosphorylated Peptidomimetics

It has been shown that the derivatives of diethyl 5‐amino‐2‐phthalimidoalkyl‐1,3‐oxazol‐4‐ylphosphonates can be employed in the synthesis of phosphorylated peptidomimetics containing the phosphonoglycine residue. The reaction of diethyl 5‐alkylamino‐2‐aminoalkyl‐1,3‐oxazol‐4‐ylphosphonates with unsaturated azlactones was utilized to obtain phosphorylated peptidomimetics with dehydroamino acid moieties. The double bond in the latter was reduced with zinc in acetic acid to provide the corresponding saturated peptidomimetics containing a diethoxyphosphoryl group in the side chain.