Synthesis of Dialkoxydimethylsilanes and 2,2-Dimethyl-1,3-dioxa- 1-Silacyclo Compounds

In the presence of iodine, magnesium reacts with alcohols to give magnesium alkoxides, which are treated with octamethylcyclotetrasiloxane to produce dialkoxydimethylsilanes. Similarly, magnesium reacts with 1,3, 1,4 and 1,5 diols and then with octamethylcyclotetrasiloxane, producing 2, 2-dimethyl-1, 3-dioxa-2-silacyclo compounds.     

Synthesis and reactivity of 1-substituted 2-fluoro- and 2,2-difluoroaziridines

A straightforward synthesis toward 2-fluorinated aziridines was developed via ring closure of beta-fluorinated beta-chloroamines, which were obtained via reduction of the corresponding alpha-fluorinated amides by borane. When 1-benzyl-2-fluoroaziridine was treated with methanol, reaction occurred at the 2-position, giving rise to N-benzyl-2,2-dimethoxyethylamine, while in the case of 1-benzyl-2,2-difluoroaziridine the 3-position was attacked, giving rise to N-benzyl-2-methoxyacetamide. These reactions point to the divergent reactive behavior of monofluoro- and difluoroaziridines.     

Synthesis and Some Chemical Properties of 2,2-Dimethyl-4-R-1-oxa-4-aza-2-sila-5-benzocycloheptanones

One-pot synthesis of 2,2-dimethyl-4-R-1-oxa-4-aza-2-sila-5-benzocycloheptanones (R = Me, CH₂SiMe₂Cl) from the N-methylamide of salicylic acid and salicylamide, respectively, by treatment of these amides with a mixture of hexamethyldisilazane and dimethylchloromethylchlorosilane was developed. The hydrolysis and other nucleophilic substitution reactions of the resultant seven-membered silacyclanes were studied. In the case of the silacyclane with R = Me, hydrolysis leads to the corresponding disiloxane, while the silacyclane with R = CH₂SiMe₂Cl gives either 2,2,6,6-tetramethyl-4-(2-hydroxybenzoyl)-2,6-disilamorpholine or its hydrochloride, depending on the reaction conditions. The chlorine atom was replaced by fluorine in the silacyclane with R = CH₂SiMe₂Cl. The structures of 2,2,6,6-tetramethyl-4-(2-hydroxybenzoyl)-2,6-disilamorpholine and its hydrochloride as well as 2,2-dimethyl-4-R-1-oxa-4-az! a-2-sila-5-benzocycloheptanones (R = CH₂SiMe₂Cl, CH₂SiMe₂F) were confirmed by X-ray diffraction.     

2,2-Dimethyl-5-(5-r-2-furfurylidene)-1,3-dioxane-4,6-diones

2,2-Dimethyl-5-(5-methyl-2-furfurylidene)-1,3-dioxane-4,6-dione crystals were subjected to an x-ray diffraction study. The unit cell of the crystal contains two symmetrically independent A and B molecules that exist in the x-cis conformation, which is stabilized by conjugation between the heteroring and, possibly, an intramolecular hydrogen bond.See [1] for Communication 1.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1453–1456, November, 1988.     

Photoaddition of Ethyl 2,2-Dimethyl-5-oxo-5,6-dihydro-2H-pyridine-1-carboxylate to 2,3-dimethylbut-2-ene

On irradiation (350 nm) in the presence of excess 2,3-dimethylbut-2-ene, the newly synthesized title compound 5 affords as main products the unexpected cyclopropylpyrrolidine 10 (50%) and the spiro-oxetane 9 (25%).     

A convenient Synthesis of 6-Substituted-2,2-Dimethyl-2H-1-Benzopyrans

Various 2,2-dimethyl-6-functional-2H-1-benzopyrans were prepared via a halogen-metal exchange reaction followed by treatment with electrophiles. These 6-functionalized chromenes are important synthetic intermediates for preparation of benzopyran-based potassium channel openers.     

5-三氟甲基-2-茚酮的合成及表征

三氟甲基化合物和茚酮化合物具有许多独特的理化性质和生物活性,在农药、医药、染料和功能材料领域应用广泛。以对三氟甲基苯甲醛为原料,经Knoevenagel缩合、分子内Friedel-Crafts酰化、环氧化物不对称开环等步骤,经9步反应以总收率22%得目标化合物5-三氟甲基-2-茚酮,其结构经1H NMR、13C NMR、DEPT、HR-ESI-MS和元素分析表征。     

Aldol dimerization of 1-indanone and 1-tetralones

The aldol dimerization of 1-indanone and 1-tetralones using titanium tetrachloride and triethylamine as condensing agents provides α,β- and β, γ-unsaturated ketones, respectively, in 53–58% yield.     

2,2-Dimethyl-5-(5-r-2-furfurylidene)-1,3-dioxan-4,6-diones. 1. Synthesis,properties, and structure

5-R-Furanaldehydes react with Meldrum's acid under Knoevenagel reaction conditions. The reaction products have s-cis conformation. The pK _a values of the electroneutral Lewis acids synthesized were determined.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1325–1329, October, 1986.     

2,2-二甲基-1-[5-二茂铁基-3-(三氟甲基)-1H-吡唑-1-基]丙-1-酮的合成及其电化学性质

以乙酰基二茂铁为原料,经3步反应合成了一个新型的二茂铁衍生物——2,2-二甲基-1-[5-二茂铁基-3-(三氟甲基)-1H-吡唑-1-基]丙-1-酮(4),其结构经1H NMR,ESI-MS,元素分析和X-射线单晶衍射表征。4属单斜晶系,P2(1)/c空间群,晶胞参数a=7.805 6(4),b=20.906 1(11),c=11.124 6(6),β=93.820(2)°,V=1 811.33(17)3,Z=4,Dc=1.482 g·cm-3,μ=0.872 mm-1,R1=0.034 8,wR2=0.089 2。采用循环伏安法研究了4的电化学性质。结果表明:4有一对可逆的氧化还原峰,Epa=0.640 V,Epc=0.482 V,ΔE=153 m V。