A Novel Synthetic Approach to (±)‐Desoxynoreseroline

(±)‐Desoxynoreseroline ( 3 ), the basic ring structure of the pharmacologically active alkaloid physostigmine ( 1 ), was synthesized starting from 3‐allyl‐1,3‐dimethyloxindole ( 9 ). The latter was prepared from the corresponding 2H‐azirin‐3‐amine 6 by a BF₃‐catalyzed ring enlargement via an amidinium intermediate 7 (Scheme 1). An alternative synthesis of 9 was also carried out by the reaction of N‐methylaniline with 2‐bromopropanoyl bromide ( 12 ), followed by intramolecular Friedel–Crafts alkylation of the formed anilide 13 to give Julian's oxindole 11 . Further alkylation of 11 with allyl bromide in the presence of LDA gave 9 in an excellent yield (Scheme 3). Ozonolysis of 9 , followed by mild reduction with (EtO)₃P, gave the aldehyde 14 , whose structure was chemically established by the transformation to the corresponding acetal 15 (Scheme 4). Condensation of 14 with hydroxylamine and hydrazine derivatives, respectively, gave the corresponding imine derivatives 16a – 16d as a mixture of syn‐ and anti‐isomers. Reduction of this mixture with LiAlH₄ proceeded by loss of ROH or RNH₂ to give racemic 3 (Scheme 5).     

Convenient Synthetic Route to (±)-Frontaliu

Frontalin, the pheromone of Dendroctonus Bark Beetles, was first isolated by Kinzer^[1] from hindgut extracts of male western pine beetles. Its structure was determined as 1,5-dimethyl-6,8-dioxabicyclo[3.2.1] octane (1) by spectral analysis and was confirmed by the synthesis of its racemate^[1,2]. On account of its structural novelty and economic value, this compound has been studied extensively ^[3-5]. But most of its synthetic methods required relatively longer steps or suffered from the inaccessibility of starting materials or reagents. Now, we report a convenient synthetic method for (±)-frontalin starting from easily available material, natural unsaturated aliphatic aicd, oleic acid. The synthesis is shown in scheme.     

A New Synthetic Route to Selected Indenones

Indenones are useful intermediates in the synthesis of several natural products, e.g. gibberellins (1) and steroid hormones with a C-nor-D-home system (2). Despite the nernerous methods for indenone synthesized, or the yields was much lower as mentioned in earlier reports (1)(4). One of the difficulties of the usual methods is the required electrophilic cyclization meta to a methoxyl substiruent. House (5) deals with these difficulties in more detail. In our method the synthesis of 6-methoxyinde-nones is effected by substitution dara to methoxyl function.     

A New Synthetic Route to 5-Isoxazolamines

5-Isoxaz0lamineshavebeenusedasintermediatesforthesynthesis0fderivatives0fantihistaminic,analgetic,antibacterial,insecticidal,herbicidalandfungicidalactivity'.Usuallytheyaresynthesizedbytheintramolecularcondensation0fhydr0xylamineand0-nitrilegr0up'.Otherapproaches,suchasreductivecyclizati0nofZ-a-cyano-6-nitroethylenesandIithiumaIuminumhydridereduction0f3-cyanooxazoleshaveals0beenrepoFted'-'.HerewerepoFtanewsyntheticrouteofthesecompounds.Ohn0andNaruse7havereportedthatthereactionof2-chlorocycl…     

A New Synthetic Route to 12-Oxo-1, 15-pentadecanlactam

12-Oxo-1,15-pentadecanlactam 7 was synthesized from cyclododecanone with a totalyield of 36% in a seven-step reaction. The azide 5 to 12-nitro-1,15-pentadecanlactam 6 is the key step featured by direct ring expansion.     

4-溴代苯酐的合成新方法

将4-硝基邻苯二甲酰亚甲胺（4-NPI）用铁粉还原为4-氨基邻苯二甲酰亚甲胺 ，再在氢氧化钠水溶液中水解成4-氨基邻苯二甲酸钠。4-氨基邻苯二甲酸钠在氢溴 酸中经Sandmeyer反应合成4-溴代苯酐。产品纯度高，是合成4-溴代苯酐的一个比较 理想的方法。     

邻氯苯甲腈的新合成法

以邻氯溴苯为起始原料,选用K4[Fe(CN)6]为氰基化试剂,Pd/C催化反应制得邻氯苯甲腈。 考察了温度、碱、催化剂的用量和原料比等对反应的影响,确定了较佳反应条件。 邻氯溴苯转化率达98.5%,产物邻氯苯甲腈得率95.1%。     

New Synthetic Route to Polyhedral Organylsilsesquioxanes

Hydrosilation of methylenecyclohexane and hex-1-ene by octa(hydridosilsesquioxane) catalysed by hexachloroplatinic acid is a new route to polyhedral organylsilsesquioxanes. Quantitative yield of octa(cyclohexylmethylsilsesquioxane) is reached. This reaction opens a vast field of yet unknown polyhedral silsesquioxanes.     

New Synthetic Route to Pummerer's Ketone

Pummerer's ketone 1 is obtained with an overall yield of 55 % by the following sequence: Claisen rearrangement of an arylcyclohexylether 3; allylic oxidation of the methylcycloalkylphenolic derivative 4b, then spontaneous cyclisation during demethylation to give 2. 1 is obtained by dehydrogenation of 2. NMR data agree with a cis stereochemistry at C_4a and C _9b.     

2-氟-6-三氟甲基苄胺的合成新方法

以2-甲基-3-三氟甲基苯胺（1）为原料,经Balz-Schiemann反应制得3-氟-2-甲基三氟甲苯（3）;3经溴代制得2-氟-6-三氟甲基苄溴(4）,最后经Gabriel反应合成2-氟-6-三氟甲基苄胺,总收率53.4%,其结构经¹H NMR和MS(ESI)确证。     

A New Route to (±) Metoprolol

Synthesis of 4-(2-methoxyethyl)phenol (5) from phenol is described. The derived aryloxyallyl ether (6) is converted into (±)-metoprolol (10) by involving dihydroxylation reaction with OsO₄ and NMO.     

磷酸特地唑胺的合成新方法

以(5R)-3-(4-溴-3-氟苯基)-5-羟甲基噁唑烷-2-酮为起始原料,在[PdCl₂(dppf)]·CH₂Cl₂催化下与联硼酸频那醇酯反应得到硼化物,继而与5-溴-2-(2-甲基-2H-四唑-5-基)吡啶进行Suzuki反应得到特地唑胺,收率82.9%。 分别考察了催化体系对硼化反应和Suzuki反应的影响,确定了较佳的反应条件。 特地唑胺与二苄基N,N-二异丙基亚磷酰胺反应得到二苄基保护的磷酸特地唑胺,随后经Pd/C脱苄得到磷酸特地唑胺,总收率66.2%。