Synthesis of 1,7-dioxaspiro[5.5]undecanes and 1-oxa-7-thiaspiro[5.5]undecanes from exo-glycal

A new spirocyclization was developed for the synthesis of 1,7-dioxaspiro[5.5]undecanes and 1-oxa-7-thiaspiro[5.5]undecanes by reaction of exo-glycal with aryl alcohols or thiophenols in the presence of Lewis acid BF₃·OEt₂. The reaction proceeded through tandem Ferrier rearrangement, glycosylation, and Friedel–Crafts alkylation to provide the corresponding products in good to excellent yields.     

Practical and divergent synthesis of 1- and 5-substituted 3,9-diazaspiro[5.5]undecanes and undecan-2-ones

A divergent synthesis of 1- and 5-substituted 3,9-diazaspiro[5.5]undecanes and undecan-2-ones is described, in which the key step is an efficient Michael addition of a lithium enolate to a tetrasubstituted olefin acceptor. A variety of substituents (butyl, phenyl, and propoxyl) were introduced at C-1(5) in this manner. In addition, an asymmetric synthesis of one member of this series was achieved using an Evans oxazolidinone chiral auxiliary reagent.     

1-(取代硅基甲硫基)甲基-2,8,9-三氧杂-5-氮杂-1-硅杂双环[3.3.3]十一烷的合成与生物活性

2,8,9一三氧杂一5一氮杂司一硅杂双环［3．3．3」十一烷（Silatrane）衍生物是一类具有广泛生物活性的五配位有机硅化合物,自6O年代发现以来一直引起人们浓厚的兴趣,随着其1位硅原子上所连基团的变化,该类化合物可表现出通然不同的生物活性［’j．为寻找新的生物活性物质,本文在Silatranel位引入一类含硅甲硫醚基团,合成了11种新的Silatrane衍生物,并初步测定了其在农药、医药方面的生物活性;同时,在其质谱中发现存在罕见的重排裂解过程．合成方法如下：回实验部分1．l仪器与试剂BrukerAC－PZOO型NMR仪,CDCI。为溶剂,TM…     

Spirans XXI. Synthesis of silaazaspiro[4.5]decanes and silaazaspiro[5.5]undecanes

N-(2-Dimethylaminopropyl)-8,8-dimethyl-8-sila-2-azaspiro[4.5]decane ( 1 ) and N-(3-dimethyl-aminopropyl)-9,9-dimethyl-9-sila-3-azaspiro[5.5]undecane ( 2 ) have been synthesized from 4,4-dimethyl-4-silacyclohexanone ( 5 ). Biological evaluation of 1 and 2 indicated cytotoxic action against human cancer cells grown in tissue culture.     

A simple and convenient synthesis of novel 9-arylidene-9,11-dihydro-8H-benzo[h]pyrano[3,4 -b]quinolin-8-ones

Research on Chemical Intermediates - In this work, a simple and convenient synthesis of a new series of benzo[h]quinoline-based α-arylidene cycloketone derivatives, namely...     

An expedient one-pot synthesis of para-tert-butylcalix[8]- and [9]arene

We report the first efficient synthesis of para-tert-butylcalix[8]arene and -[9]arene via an exceptionally straightforward innovative protocol that takes place at ambient temperature, employing readily available tin(IV) chloride and s-trioxane.     

Spirans XX. Synthesis of 8,8-dialkylazaspiro[4.5] decanes and 9,9-dialkylazaspiro[5.5]undecanes

N-(2-Dimethylaminopropyl)-8,8-dimethyl-2-azaspiro[4.5]decane ( 1 ), N-(2-dimethylaminopropyl)-8,8-diethyl-2-azaspiro[4.5]decane ( 2 ), N-(3-dimethylaminopropyl)-9,9-dimethyl-3-azaspiro[5.5]undecane ( 3 ), and N-(3-dimethylaminopropyl)-9,9-diethyl-3-azaspiro[5.5]undecane ( 4 ) have been synthesized from 4,4-dimethylcyclohexanone ( 5 ) and 4,4-diethylcyclohexanone ( 6 ). Biological evaluation of these amines showed significant inhibition of cancer cell growth in human cancer cells grown in tissue culture.     

A convenient synthesis of 9H-dibenz[c,f]imidazo[1,2-a]azepin-9-ones

A convenient three step synthesis of 9H-dibenz[c,f]imidazo[1,2-a]azepin-9-ones from readily available 2-phenylimidazoline and a methyl benzoate is described.     

Proximity effects in 1-azaspirocyclo[5.5]undecanes. X-ray structure determination of a diol derivative

Neighbouring group participation is used to control bromination of the alkene (1) to give the bromo-acetate (3) which is converted into the diol (6a) [characterised by X-ray structure determination of the cyclic carbamate (8)] and the epoxide (2).     

A convenient synthesis of functionalized 1H-pyrimidine-2-thiones

The furan-2,3-dione 1 and the thiosemicarbazones 2 combine with loss of carbon dioxide and water yielding the 1-methylenaminopyrimidine-2-thione derivatives 3 in moderate yields (30–60%). Their molecular skeleton is confirmed with aid of an X-ray structure determination of 3c . Hydrolysis of 3 leads to the 1-aminopyrimidine-2-thione 5 .     

Synthesis of substituted 3,9-diazaspiro[5.5]undecanes via spirocyclization of pyridine substrates

Construction of 3,9-diazaspiro[5.5]undecane derivatives can be easily achieved via intramolecular spirocyclization of 4-substituted pyridines. The reaction entails in situ activation of the pyridine ring with ethyl chloroformate followed by intramolecular addition of an attached β-dicarbonyl nucleophile in the presence of Ti(OⁱPr)₄.     

具有生物活性的有机硅化合物的研究IX:1-(N-芳基呋喃甲酰胺)亚甲基-2,8,9-三氧杂-5-氮杂-1-硅杂三环[3.3.3.O^1^.^5]十一烷的合成

本文合成了六个1-(N-芳基呋喃甲酰胺)亚甲基-2,8,9-三氧杂-5-氮杂-1-硅杂三环[3.3.3.O^1^.^5]十一烷的化合物。合成方法简便, 反应时间短。易于后处理。经元素分析, IR, ^1H NMR, MS确定了新化合物的结构, 并经化合物3的X射线晶格衍射分析确定了该类化合物的空间排布情况。     

6-Aryl-1-azabicyclo [5.4.0] undecanes

Some 6-aryl-6-hydroxy-l-azabicyclo[5.4.0]undecanes and their esters were synthesized as potential cardiovascular agents and analgetics of the proheptazine type, respectively. Also, 6-aryl-1-azabicyclo[5.4.0]undecanes were prepared as rigid structures related to the phenethylamine CNS stimulants.     

Diastereoselective spiroannulation of phenolic substrates: synthesis of (+/-)-2-tert-butyl-6-methoxy-1-oxaspiro[4,5]deca-6,9-diene-8-one

The synthesis of a new spiroether is described. The title compound is obtained as a diastereomeric mixture in 45% yield.     

Syntheses of Racemic and Optically Active 4-Hydroxy-2-hydroxymethyl-1,7-dioxaspiro[5.5]undecanes

Racemic and optically active 4-hydroxy-2-hydroxymethyl-1,7-dioxaspiro[5.5]undecanes were prepared in six steps from butane-1,2,4-triol and valerolactone with the longest linear sequence being four steps.     

Flexible synthesis of enantiomerically pure 2,8-dialkyl-1,7-dioxaspiro[5.5]undecanes and 2,7-dialkyl-1,6-dioxaspiro[4.5]decanes from propargylic and homopropargylic alcohols

A new approach to enantiomerically pure 2,8-dialkyl-1,7-dioxaspiro[5.5]undecanes and 2,7-dialkyl-1,6-dioxaspiro[4.5]decanes is described and utilizes enantiomerically pure homopropargylic alcohols obtained from lithium acetylide opening of enantiomerically pure epoxides, which are, in turn, acquired by hydrolytic kinetic resolution of the corresponding racemic epoxides. Alkyne carboxylation and conversion to the Weinreb amide may be followed by triple-bond manipulation prior to reaction with a second alkynyllithium derived from a homo- or propargylic alcohol. In this way, the two ring components of the spiroacetal are individually constructed, with deprotection and cyclization affording the spiroacetal. The procedure is illustrated by acquisition of (2S,5R,7S) and (2R,5R,7S)-2-n-butyl-7-methyl-1,6-dioxaspiro[4.5]-decanes (1), (2S,6R,8S)-2-methyl-8-n-pentyl-1,7-dioxaspiro[5.5]undecane (2), and (2S,6R,8S)-2-methyl-8-n-propyl-1,7-dioxaspiro[5.5]undecane (3). The widely distributed insect component, (2S,6R,8S)-2,8-dimethyl-1,7-dioxaspiro[5.5]undecane (4), was acquired by linking two identical alkyne precursors via ethyl formate. In addition, [(2)H(4)]-regioisomers, 10,10,11,11-[(2)H(4)] and 4,4,5,5-[(2)H(4)] of 3 and 4,4,5,5-[(2)H(4)]-4, were acquired by triple-bond deuteration, using deuterium gas and Wilkinson's catalyst. This alkyne-based approach is, in principle, applicable to more complex spiroacetal systems not only by use of more elaborate alkynes but also by triple-bond functionalization during the general sequence.