新型双吲哚马来酰亚胺衍生物的合成

以1-(3-氧代四氢吡喃丙基)-吲哚-3-乙醛酸甲酯(5)和吲哚-3-乙酰胺(6)为原料,在催化剂叔丁醇钾的四氢呋喃溶液存在下发生偶合反应,经浓盐酸处理得脱保护的中间体7,再经甲磺酰化反应、氨解反应得到4种新的具有不同氨烷基侧链的双吲哚马来酰亚胺衍生物9a,9b,9d,9e.目标产物结构通过1H NMR,13C NMR,MS和HRMS确证.     

Reactive iron carbonyl reagents via reaction of metal alkoxides with Fe(CO)5 or Fe2(CO)9: synthesis of cyclobutenediones via double carbonylation of alkynes

Alkoxy bases such as t-BuOK react with Fe(CO)(5) to give reactive iron carbonyl intermediates that in turn react with alkynes at 70 °C in THF to give 1,2-cyclobutenediones in 70-93% yields after CuCl(2)·2H(2)O oxidation. A novel 1,2-diacyloxyferrole derivative was isolated in the reaction of diphenylacetylene with Fe(CO)(5)/t-BuOK in the presence of acetyl chloride in contrast to the formation of a 1,4-diacyloxyferrole complex formed in the reaction using Fe(CO)(5)/Me(3)NO. The Fe(2)(CO)(9)/t-BuOK reagent system also converts the alkynes to corresponding cyclobutenediones in 63-90% yields under similar reaction conditions.     

Guerbet reaction of primary alcohols leading to beta-alkylated dimer alcohols catalyzed by iridium complexes

[IrCl(cod)]2 and [Cp*IrCl2]2 complexes catalyzed efficiently the Guerbet reaction of primary alcohols to beta-alkylated dimer alcohols in good yields. For instance, the reaction of 1-butanol in the presence of [Cp*IrCl2]2 (1 mol %), t-BuOK (40 mol %), and 1,7-octadiene (10 mol %) produced 2-ethyl-1-hexanol in 93% yield. Various primary alcohols undergo the Guerbet reaction under the influence of Ir complexes to give the corresponding dimer alcohols in good yields. This method provides an alternative direct route to beta-alkylated primary alcohols which are prepared by aldol condensation of aldehydes followed by hydrogenation.     

10-Alkenylphenothiazines. 1. Synthesis and cis,trans-isomerization of 10-propenylphenothiazines

A study was carried out on the isomerization of 10-allylphenothiazine (I) in DMSO by the action of t-BuOK, KOH and NaOH. The isomerization proceeds stereospecifically at room temperature by the action of t-BuOK at an elevated temperature by the action of KOH and NaOH to give cis-10-propenylphenothiazine (II). The effect of the t-BuOK concentration, temperature and reaction time on the isomeric composition of the 10-propenylphenothiazines formed was studied. Under conditions of kinetic control, I gives II, which isomerizes under the reaction conditions to give an equilibrium mixture of cis- and trans-10-propenyl-phenothiazine with 44–45% trans isomer III. The isomerization temperature has virtually no effect on the II/III isomer ratio.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 121–124, January, 1986.     

Bis(2,2,2-trifluoroethyl)bromophosphonoacetate, a Novel HWE Reagent for the Preparation of (E)-alpha-Bromoacrylates: A General and Stereoselective Method for the Synthesis of Trisubstituted Alkenes

A novel reagent, methyl bis(2,2,2-trifluoroethoxy)bromophosphonoacetate (3a), was designed and prepared in order to efficiently synthesize (E)-alpha-bromoacrylates, which are useful precursors for various C-C bond formations. Honer-Wadsworth-Emmons (HWE) reaction of various aldehydes with 3a in the presence of t-BuOK and 18-C-6 gave the corresponding (E)-alpha-bromoacrylate derivatives with high stereoselectivity. Using the (E)-alpha-bromoacrylate as a key intermediate, a general stereoselective synthesis of trisubstituted alkenes via Pd-catalyzed cross-coupling was developed.     

Sc(OTf)3-catalyzed or t-BuOK promoted tandem reaction of 2-(2-(alkynyl)benzylidene)malonate with indole

Tandem reaction of 2-(2-(alkynyl)benzylidene)malonate with indole was investigated. (Z)-1-Benzylidene-3-(1 H-indol-1-yl)-1 H-indene-2,2(3 H)-dicarboxylate was generated in the presence of t-BuOK at room temperature; whereas 3-((1 H-indol-3-yl)(2-(alkynyl)aryl)methyl)-1 H-indole was obtained when Sc(OTf)3 was utilized as catalyst at 50 degrees C.     

A novel rearrangement to 1,2,4-triazolo[1,5-a]quinoxalines

Reactions of benzyl bromide or benzyl cinnamate with N-(benzotriazol-1-ylmethyl)arylimidoyl chlorides (2a,b) in the presence of t-BuOK occur with opening of the benzotriazole ring affording 1,2,4-triazolo[1,5-a]quinoxalines (3a,b). A possible reaction mechanism is discussed.     

All-carbon-substituted vinylsilane stable to TBAF: synthesis of allyldimethylvinylsilane and its Pd-catalyzed cross-coupling under mild conditions

[reaction: see text] Allyldimethylvinylsilanes 3 are easily synthesized by the reaction of silylallylmetals, generated from 1 by n-BuLi/t-BuOK, with carbonyl compounds in the absence or presence of metal halides. They can tolerate 2 equiv of TBAF in THF at room temperature for at least 6 h but can be easily activated in the presence of a palladium catalyst and TBAF to perform the cross-coupling reaction with aryl iodides at room temperature.     

Reactions of 2-Phosphonylethynylated 2-(Arylamino)malonates with Some Bases

Russian Journal of General Chemistry - The reaction of dialkyl 2-[(dialkoxyphosphoryl)ethynyl]-2-(arylamino)malonates with bases (CH3COOK, t-BuOK) can serve as a method for preparing original...     

New stereoselective beta-glycosylation via a vinyl oxirane derived from D-glucal

[reaction: see text] The reaction of the vinyl oxirane 1 derived from D-glucal with a series of O-nucleophiles (alcohols, phenol, and diacetone D-glucose) affords the corresponding 2-unsaturated beta-O-glycosides in a completely stereoselective way (syn 1,4-addition pathway). Epoxide 1 is generated in situ by treatment of the corresponding hydroxy mesylate 2 with t-BuOK in anhydrous benzene.     

Direkte und indirekte metallierung von endo-dicylopentadien. Sn- und C-NMR studie stannylierter folgeprodukte

endo-Dicyclopentadiene (1) can be metalated by use of simple procedures with good overall yields. The attack occurs at the various vinyl, rather than at the allyl, positions of 1 as was confirmed by trapping the carbanions with Me₃SnCl. When t-BuLi/TMEDA are used, the 8- and 9-stannyl derivatives (3 and 4) are formed, whereas an excess of n-BuLi/t-BuOK leads to doubly stannylated derivatives with Me₃Sn groups in position 4/8 (6), 4/9 (7), and 3/9 (8) in addition to 3 and 4. Furthermore the latter reaction yields 5,5-bis(trimethylstannyl)cyclopentadiene (5). With stoichiometric amounts of n-BuLi/t-BuOK the formation of 3 and 4 predominates over that of 5–8. 5 is obtained from 1 after deprotonation at the allyl position, followed by an extremely fast retro-Diels-Alder reaction and then by further deprotonation. This follows from two experiments: (1) exo- and endo-5-trimethylstannyl-endo-dicyclopentadiene (11 and 12) which are synthesized from 1 in three steps give cyclopentadienyllithium and 1 when treated with methyllithium at −78°C; (2) cyclopentadiene reacts with an excess of n-BuLi/t-BuOK and Me₃SnCl to give 5. When 12 is heated syn-10-trimethylstannyl-endo-dicyclopentadiene (13) is obtained. The eight stannyl derivatives of 1 are identified mainly from the following NMR parameters: δ(¹¹⁹Sn), δ(¹³C), δ(¹H), ⁿJ(^119/117Sn---¹³C), and ⁶J(¹¹⁹Sn---^119/117Sn). The ¹³C NMR satellite spectrum of 1 yields the isotope shifts ¹Δ¹³(i(¹³C(j)) and ¹J(¹³C---¹³C). The latter lead to the revision of earlier signal assignments.     

Reactions of 1-halocyclohexenes and methyl substituted 1-halocyclohexenes with potassium t-butoxide

Reactions of 1-halocyclohexenes and 1-halo-4-methylcyclohexenes with potassium t-butoxide (t-BuOK) in dimethyl sulfoxide and tetrahydrofuran have been shown to take place by three competing dehydrohalogenation mechanisms. These are: dehydrohalogenation across the C₁C₆ bond to give a cyclohexyne; dehydrohalogenation across the C₁C₆ bond to give a 1,2-cyclohexadiene: and prototropic rearrangement to the corresponding 3-halocyclohexene, followed by β-elimination to a 1,3-cyclohexadiene. The highly strained cyclohexyne and 1,2-cyclohexadiene intermediates react with t-BuOK to give 1-t-butoxycyclohexene, which is obtained in yields ranging from 5–20% in DMSO to about 60% in THF. Competitive with the substitution reaction is dimerization of 1,2-cyclohexadiene to tricyclo[6.4.0.0^2,7]-dodeca-2,12-diene, and 1,2- and 1,4-cycloaddition of 1,2- and 1,3-cyclohexadiene.     

(±)-19-去甲基-4(18),8,11,13-四烯-松香烷-7-酮的全合成

以间异丙基溴苯1为起始原料,通过进攻环氧乙烷及溴代两步制得溴化物3.溴化物3与Hagemann′s酯发生偶联反应,水解后生成偶联产物5.再以路易斯酸BF3·Et2O催化化合物5进行分子内环化为关键步骤得到反式稠合中间体6,最后通过与三苯基膦碘甲烷季盐发生Wittig反应及氧化,合成了(±)-19-去甲基-4(18),8,11,13-四烯-松香烷-7-酮[19-nor-abieta-4(18),8,11,13-tetraen-7-one](8).     

Reactions of boroxazolidones with aromatic aldehydes : An easy route to derivatives of isoquinoline and iso-indolinone

Boroxazolidones 1 derived from glycine and phenylalanine react with aromatic aldehydes to form the corresponding imines. The product 3 from 1a with o-carboxybenzaldehyde is converted into 4-hydroxyisoquinoline-3-carboxylic acid 6 by dimethyl sulfate, followed by t-BuOK, and aqueous acid.

With o-phthalaldehyde and 1a,b the isoindolinones 11a,b are obtained. These reactions proceed via carboxylic acids 9. Compound 9a was also prepared from 3 by catalytic, hydrogenation. Salicylaldehyde and 1a gave polymeric material, but the preformed Schiff's base 13 can be transformed into the p-nitrobenzyl ester 15 by treatment successively with dicyclohexylamine, triethylborane and p-nitrobenzyl bromide.     

Ru(II)-SDP-complex-catalyzed asymmetric hydrogenation of ketones. Effect of the alkali metal cation in the reaction

The Ru(II) complexes of SDP and DPEN combined with t-BuOK in 2-propanol formed a very effective catalyst for the hydrogenation of simple aromatic ketones with high activity and enantioselectivity. The racemic alpha-arylcycloalkanones can also be hydrogenated by this system, providing alpha-arylcycloalkanols in excellent cis/trans stereoselectivity (>99:1) and enantioselectivity (up to 99.9%) for the cis isomer. In the study of the effect of the alkali metal cation in the hydrogenation of acetophenone using RuCl(2)(Tol-SDP)(DPEN) and RuCl(2)(Xyl-SDP)(DPEN) catalysts, we found that t-BuONa provided a faster reaction than t-BuOK, which indicated that the sterically hindered diphosphine ligands preferred the base with the smaller metal cation.     

光学活性噻吗洛尔的合成

噻呜洛尔(Timolol)是一种新型的β-受体阻断剂。化学名为S-(-)-1-叔丁胺基-3-[(4-吗啉代-1,2,5-噻二唑-3-基)氧]-2-丙醇顺丁烯二酸盐。     

First Example of the Aza-Favorskii Reaction. Ethynylation of C=N Bond in the Superbasic System t-BuOK–DMSO

Russian Journal of Organic Chemistry - Direct ethynylation of ketimines with alkynes in the superbasic system t-BuOK–DMSO has been accomplished for the first time using the reaction of...     

高效大量合成AF-5的中间体:(4aR,7R)-1-丁基 -4a-甲基-7-(1-甲基-1-羟乙基)-2(1H)-八氢萘酮

化合物(4 aR,7R)-1-丁基-4 a-甲基-7-(1-甲基-1-羟乙基)-2(1H)-八氢萘酮是合成AF-5的重要中间体,传统方法是在强碱叔丁醇钾的作用下对化合物(4 aR,7R)-4 a-甲基-7-(1-甲基-1-羟乙基)-2(1H)-八氢萘酮进行烷基化反应而得到的.为了使操作更方便、安全,适合大量制备,并提高收率,作者探索了多种碱性条件,并选择氢氧化钾的叔丁醇溶液代替叔丁醇钾,最终使该步烷基化反应可以工业化.     

Intermolecular reactions of chlorohydrine anions: acetalization of carbonyl compounds under basic conditions

[reaction: see text] Nonenolizable aldehydes and ketones react with 2-chloroethanol and 3-chloropropanol under basic conditions (t-BuOK, DMF/THF) with formation of 2-substituted 1,3-dioxolanes and 1,3-dioxanes, respectively. Conversion of the two-step addition-alkylation process depends on the electrophilicity of the carbonyl group that governs the equilibrium of addition of chloroalkoxides. This method of protection of carbonyl groups in the form of cyclic acetals under kinetically controlled conditions is complementary to the acid-catalyzed reaction with diols.     

N-hetarylethylenes. 1. Synthesis and isomerization of 10-allyland 10-propenylphenoxazines

Alkylation of phenoxazine with allyl bromide has given 10-allylphenoxazine. The prototropic isomerization of 10-allylphenoxazine in DMSO on treatment with t-BuOK, KOH, and NaOH has been examined. At elevated temperatures, mixtures of cis- and trans-10-propenylphenoxazines are formed, but at room temperature in the presence of t-BuOK isomerization proceeds stereoselectively to give cis-10-propenylphenoxazine. The influence of temperature and reaction times on the isomeric composition of the 10-propenylphenoxazines has been studied. The cis-propenylphenoxazine obtained in the kinetically controlled reaction isomerizes under the reaction conditions to the equilibrium mixture of cis- and transisomers of 10-propenylphenoxazine.For preceding communication, see [1]. The series N-Hetarylethylenes comprises 9-alkenyl-carbazoles, 10-alkenylphenothiazines, and 10-alkenylphenoxazines.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12,. pp. 1674–1678, December, 1988.