摘要:

Studies involving selective functionalization of the indole unit in a number of bisindole alkaloids and related synthetic derivatives are described. These investigations include such reagents astert-butyl hydroperoxide, which provides an efficient procedure for epoxidation of olefinic linkages, mercuric acetate, osmium tetroxide, and iodine under basic conditions and oxygenation under acidic conditions. Efficient syntheses of leurosine (8) and various novel vinblastine derivatives are developed.

ISSN:0008-4042    

DOI:10.1139/v78-011

出版商:NRC Research Press    

年代:1978

数据来源: NRC

摘要:

Treatment of 3-chloro-1-phenylpropylene oxide-1,2 (7) or 1-chloro-4-phenylbutylene oxide-3,4 (8) with H2S saturated ethanolic NaOEt gave 3-hydroxy-2-phenylthietane (9) and 3-hydroxy-2-phenylthiolane (10) respectively. A similar treatment of 3-chloro-2-phenylpropylene oxide-1,2 (12) at low temperatures gave 3-chloro-2-hydroxy-2-phenylpropanethiol (13); at reflux temperatures or by refluxing13in ethanolic NaOEt, 3-hydroxy-3-phenylthietane (14) was formed.Oxidation of9,10, and14withm-chloroperbenzoic acid or H2O2–HOAc gave the respective 1,1-dioxides19, 20, and25. The alcohols19and20were dehydrated to their corresponding cyclic olefins through the benzylsulfonate esters. Under the conditions of the Ritter reaction25dehydrated to the cyclic olefin. Treatment of19with mineral acid gave benzyl methyl ketone, while refluxing19in base gave benzyl methyl sulfone. Ethoxylation of 2-phenylthiete 1,1-dioxide (23) to the 3-ethoxy derivative34was achieved under basic conditions. Attempted chlorination of9resulted in desulfurization to 3-chloropropenylbenzene (5).

ISSN:0008-4042    

DOI:10.1139/v78-012

出版商:NRC Research Press    

年代:1978

数据来源: NRC

摘要:

The cyclopentadienide analog of triptycene1and the tropylium cation analog of triptycene 2 have been synthesized. Some comparative spectroscopic data of these ions relative to triptycene are discussed.

ISSN:0008-4042    

DOI:10.1139/v78-013

出版商:NRC Research Press    

年代:1978

数据来源: NRC

摘要:

Carbon-13 nmr spectra have been recorded for 25 oxa- and azabicyclo[3.3.1]- and -[4.2.1]nonanes. Results obtained for the 9-oxabicyclo[3.3.1]nonanes, 2-substituted by hydroxyl or alkyl- and phenylamino groups, as well as those obtained for theN-alkyl- orN-phenyl-9-azabicyclo[3.3.1]nonan-2-ols, provide supplementary information regarding the previously studied structures of these types. Shielding and deshielding due to γ and δ steric interactions were observed depending on the substituent. The study of the oxabicyclo[4.2.1]nonanes, substituted or not substituted in positions 2 and 7 by hydroxyl groups, and of the azabicyclo[4.2.1]nonanes substituted in position 2 by the same group, yields interesting results on the conformational equilibria in these compounds which is caused by the flexibility of the seven-membered ring. The conformational equilibrium is displaced toward the boat form of the seven-membered ring for the unsubstituted compounds.Gaucheconformations are proposed for the other compounds in order to account for the experimental observations; the pure chair and boat forms are excluded. Two ketones also have been studied. [Journal translation]

ISSN:0008-4042    

DOI:10.1139/v78-014

出版商:NRC Research Press    

年代:1978

数据来源: NRC

摘要:

Stereospecific methods of synthesis of somecis-andtrans-bicyclo[n.3.0]alkane-1-carboxylic acids are described, specifically5a,5b, and11. Thecisring fusion is insured by use of the Diels–Alder reaction, and thetransring fusion is fixed by the necessity of acisattachment of an intermediate five-membered cyclic lactamol to the existing cyclopentane ring in9.

ISSN:0008-4042    

DOI:10.1139/v78-015

出版商:NRC Research Press    

年代:1978

数据来源: NRC

摘要:

A series of cyclobutanones1–5were found to rearrange to β-tetralones6–10, respectively, in the presence of phosphorous pentoxide in benzene at room temperature. The structures of the β-tetralones were inferred by conversion of a number of these known naphthalene derivatives. Possible mechanistic pathways are discussed.

ISSN:0008-4042    

DOI:10.1139/v78-016

出版商:NRC Research Press    

年代:1978

数据来源: NRC

摘要:

The effect of 18-crown-6 ether3on the decarboxylation rate in THF of sodium salts of carboxylic acids formally derived from hydrocarbons has been investigated and these acids include 9-phenylfluorene-9-carboxylic acid, fluorene-9-carboxylic acid, phenylacetylene carboxylic acid, triphenylacetic acid, and diphenylacetic acid. Addition of equimolar3resulted in an increase in decarboxylation rate of 13- to 500-fold and there was a correlation between the decarboxylation rate and the pKavalue of the product hydrocarbon.The decarboxylation of triphenylacetate was investigated in detail. The effect on reaction rate of cation (Li+, Na+, K+), crown ether concentration, water concentration, and solvent polarity has provided information as to optimum reaction conditions and has helped to clarify the reaction mechanism.

ISSN:0008-4042    

DOI:10.1139/v78-017

出版商:NRC Research Press    

年代:1978

数据来源: NRC

摘要:

The mercury photosensitized decomposition of thietane vapour at room temperature has been studied. Quantum yields of the products, ethylene, propylene, cyclopropane, 1,2-dithiocane, and 1,5-hexadiene, have been measured as a function of substrate pressure, percent decomposition, and intensity and the influence of added NO and propylene has been examined. At low pressures quantum yields of thietane decomposition exceed unity. A mechanism involving thiatrimethylene and 4,5-dithiahexamethylene biradicals is proposed.

ISSN:0008-4042    

DOI:10.1139/v78-018

出版商:NRC Research Press    

年代:1978

数据来源: NRC

摘要:

The chromous chloride promoted addition ofN-chlorocarbamates andN-chlorocarboxamides to 1-methoxycyclohexene, ethoxyethylene, dihydropyran, and (1-methoxyethylidene)-cyclohexane gave, in 60 to 85% yields, either α-acyloxy- or α-acylamino ketals and acetals, or the corresponding ketones and aldehydes depending on the work-up conditions. The regio-specificity of the addition was higher with the first two enol ethers (≥97%) than with the latter two (≥85%).N-Chlorourethane was added to 17-methoxymethylenandrost-4-en-3-one (19) and the sole addition product isolated was the 17α-chloro-20-ethoxycarbonylamino derivative20in 75% yield. Additions to triacetyl-D-glucal and 3-O-acetyl-4,6-O-benzylidene-D-glucal followed by solvolysis under Koenigs–Knorr conditions led predominantly to 2-amino-gluco-pyranosides in 30 to 65% yields, whereas additions to 3-O-acetyl-4,6-O-benzylidene-D-allal gave 2-amino altropyranosides in 40 to 56% yields.

ISSN:0008-4042    

DOI:10.1139/v78-019

出版商:NRC Research Press    

年代:1978

数据来源: NRC

摘要:

The kinetics and energetics of proton removal from propene, which contains several sites of different acidities, were investigated both theoretically and experimentally. Rate and equilibrium constants were measured for the proton-transfer reactionat 296 ± 2 K using the flowing afterglow technique. The rate constants were determined to bekforward = (1.1 ± 0.3) × 10−9 cm3molecule−1s−1andkreverse = (5.4 ± 1.9) × 10−10 cm3molecule−1s−1. The ratio of rate constants,kf/kr = 2.1 ± 0.7, was found to be in agreement with the equilibrium constant,K = 2.2 ± 0.8, determined from equilibrium concentrations.Abinitiomolecular orbital calculations predicted the removal of a methyl proton from propene to yield the allyl anion to be energetically favoured. This prediction was supported by measurements of deuteron removal from CD3CHCH2. The measured value ofKcorresponds to a standard free energy change, ΔG0298, of −0.44 ± 0.14 kcal mol−1which provided values for the standard enthalpy change ΔH0298 = +0.5 ± 0.4 kcal mol−1, the proton affinity, PA298(C3H5−) = 391 ± 1 kcal mol−1, the heat of formation, ΔH0f,298(C3H5−) = 29.0 ± 0.8 kcal mol−1, and the electron affinity EA(CH2CHCH2) = 12.4 ± 1.9 kcal mol−1. The experimentally established value for the proton affinity of the allyl anion was in reasonable accord with the value of 422.3 kcal mol−1determined by calculation. The electron affinity of the allyl radical derived in this study is supported by previous calculations and several limiting values obtained experimentally.

ISSN:0008-4042    

DOI:10.1139/v78-020

出版商:NRC Research Press    

年代:1978

数据来源: NRC