Synthesis of 1,2-bis(methoxyamino)cycloalkanes from alicyclic 1,2-bis(hydroxyamines)

Derivatives of 1,4-dihydroxypiperazine-2,3-dione were obtained by reaction of cis-1,2-bis(hydroxyamino)cycloalkanes with diethyl oxalate. Their alkylation with CH₂N₂ or Mel afforded 1,4-dimethoxypiperazine-2,3-diones. Hydrolysis of the latter gave 1,2-bis(methoxyamino)cycloalkanes.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 4, pp. 925–929, April, 1996.     

The first example of the C-3 alkylation of indoles with cyclopropyl ketones promoted by CeCl3·7H2O/LiI

Indoles undergo smooth alkylation with cyclopropyl ketones in the presence of the CeCl₃·7H₂O/LiI reagent system in refluxing acetonitrile under neutral conditions to produce the corresponding C-3 substituted indole derivatives in good to high yields and with high selectivity. The use of CeCl₃·7H₂O/LiI makes this method simple, convenient, and cost-effective.     

Reaction of indium ate complexes with allylic compounds. Controlling SN2/SN2′ selectivity by solvents

Vinyl and methylindium ate complexes (indates) were prepared and both the tendency of immigration and regioselectivity toward cinnamyl bromide were investigated. The vinyl group was more preferably transferred than the Me group, giving a regioisomeric mixture of S_N2 and S_N2′ products. The ratio of S_N2/S_N2′ selectivity can be controlled by solvents; in the presence of polar solvents, such as N-butylpyrrolidone (NBP) and THF, the S_N2′ product was mainly obtained, whereas the S_N2 product was selectively prepared in solutions containing hexane. The vinylindium compound, generated by the reaction of allylic-type diindium reagents with imine, was also converted to the corresponding vinyl indate, which was allowed to react with allyl chloride to give a three-component coupling product.     

Microwave-assisted arylation of rac-(E)-3-acetoxy-1,3-diphenylprop-1-ene with arylboronic acids

The palladium-catalyzed arylation of rac-(E)-3-acetoxy-1,3-diphenylprop-1-ene with arylboronic acids was studied under controlled microwave irradiation conditions. A variety of different catalysts, bases, and solvents were explored in order to achieve optimum yields in the shortest possible reaction times. The best isolated yields were obtained using Pd₂(dba)₃·CHCl₃/PPh₃ as the catalytic system, potassium phosphate monohydrate as the base, and toluene/H₂O as a solvent system. Microwave irradiation using 5 mol % of the palladium catalyst for 90 s (max. temp 170 °C) generally afforded the cross-coupling products in good to excellent yields.     

Reaction of haloadamantanes with salts of nitro compounds

Silver and mercury salts of nitro compounds react with bromo- or chloroadamantanes with the formation of products of C- and/or O-alkylation, the ratio of which depends on the structure of the initial reactants. The direct experimental evidence of nitronic esters to be isomerized into nitro derivatives and of their role as intermediates in the formation of the nitro derivatives in the alkylation of nitro compounds has been presented for the first time.N. D. Zelinskii Institute of Organic Chemistry, Russian Academy of Sciences, 117913 Moscow. Translated from Izvestiva Akademii Nauk, Seriya Khimicheskaya, No. 8, pp. 1798–1803, August, 1992.     

A novel heterocyclic system — dihydro-2H-1,5,2,4-dioxadiazine. 2,4-Dimethyldihydro-2H-1,5,2,4-dioxadiazine hydrochloride: synthesis and NMR study

The first representative of a novel heterocyclic system, namely, 2,4-dimethyldihydro-2H-1,5,2,4-dioxadiazine hydrochloride, was synthesized.     

甲苯甲醇侧链烷基化反应中沸石催化剂酸碱中心的作用Ⅱ．改性的X型和双组分改性的X／ZSM－5双沸石催化剂

制备了改性的ｘ型和ｘ／ＺＳＭ－５型沸石催化剂，并对其进行了评价和ＴＰＤ、ＥＳＣＡ表征，将实验结果进行了关联。结果表明，采用ＫＯＨ，Ｈ＿３ＢＯ＿３和碱土金属化合物等作为改性剂，可以调变沸石催化剂的酸碱中心，其中碱酸密度比为０．５３９的ＫＸ（Ｂ＿３）·ＫＺＳＭ－５（Ｃａ）催化剂，能显著提高甲苯、甲醇侧链烷基化制取苯乙烯反应的选择性和收率。井根据对实验结果的分析，初步探讨了甲苯、甲醇侧链烷基化反应的机理。     

Diastereoselective addition of organolithiums to 1,3-oxazolidines complexed with aluminum tris(2,6-diphenylphenoxide) (ATPH)

1,3-Oxazolidines were easily obtained by condensation of N-substituted (R)-phenylglycinol with aldehydes. Addition of organolithium reagents to 1,3-oxazolidines by complexation with the bulky Lewis acid aluminum tris(2,6-diphenylphenoxide) (ATPH) readily produced the corresponding chiral amines with good yield and high diastereoselectivity. The configuration of the new stereogenic center was shown to be opposite to that of adducts obtained for the same 1,3-oxazolidines using Grignard reagents. The best diastereoselectivity was achieved using N-isopropyl-1,3-oxazolidines. The mechanism of addition was deduced by determining the stereochemistry of the iminium-aluminum complex by NOE experiments.     

L-半胱氨酸衍生物的合成及应用

以L-半胱氨酸为手性源，合成了二类多官能团的化合物6和7，并用于醛的不对 称烷基化反应，同时研究了催化剂的结构对反应结果的影响．     

1,2,4-三苯基环戊二烯的合成及其烷基化反应

测定了颇哪醇在酸性条件下所得的脱水产物的分子结构.结果表明,在酸性条件下颇哪醇的脱水反应优于重排反应,由此合成了1,2,4-三苯基环戊二烯.该环戊二烯衍生物的烷基化反应,在通常条件下优先发生在碳环的第5位碳原子上,但在苛刻的剧烈反应条件下,进而发生在碳环的第3位碳原子上.讨论了脱水反应和烷基化反应的机理.