摘要:

The p.m.r. spectra of 2-vinylpyridine, 2-methyl-5-vinylpyridine, and 4-vinylpyridine are examined for long-range coupling constants between the vinylic and ring protons. Those over six, seven, and eight bonds from the vinyl group to ring or methyl protons in theparaposition are dominated by a π electron mechanism. Those over five bonds between the α proton and a ring proton in themetaposition indicate that the vinyl group prefers to liecisto the nitrogen in 2-vinylpyridine buttransin the 5-vinylpyridine. INDO-MO-FPT calculations of coupling constants between vinyl protons and ring protons, carbon-13, and nitrogen-14 nuclei are presented in graphical form.

ISSN:0008-4042    

DOI:10.1139/v74-021

出版商:NRC Research Press    

年代:1974

数据来源: NRC

摘要:

The AlCl3-promoted reactions of 2,5-dimethyl- and of 2,5-diphenylfuran with ethyl propiolate afford as major products ethyl 2,6-dimethyl-3-hydroxybenzoate (6a) and ethyl 3,5-diphenyl-2-hydroxybenzoate (8b), respectively. Also isolated from these reactions were ethyl 2,4-dimethyl-5-hydroxybenzoate (7a), ethyl 3,5-dimethyl-2-hydroxybenzoate (8a), ethyl 2,4-diphenyl-5-hydroxybenzoate (7b), and ethyl 2,6-diphenyl-3-hydroxybenzoate (6b). Minor by-products weretransethyl 3-(2,5-dimethyl-3-furyl-acrylate (10) and ethyl 3-acetyl-2-(2,5-dimethyl-3-furyl)-5-methyl-cyclopenta-2,5-dienecarboxylate (11).

ISSN:0008-4042    

DOI:10.1139/v74-022

出版商:NRC Research Press    

年代:1974

数据来源: NRC

摘要:

The p.m.r. spectra of 1,4-dichlorobenzene-(13C and12C) partially oriented in nematic phases have been measured and analyzed, and the geometry of the molecule has been determined. The angleis found to be 119.4° and120.3°. TheJCHare determined using spectra of samples with differing degrees of orientation.

ISSN:0008-4042    

DOI:10.1139/v74-023

出版商:NRC Research Press    

年代:1974

数据来源: NRC

摘要:

A semiempirical self-consistent field molecular orbital study has been made on some nonbenzenoid hydrocarbons using a resonance integral value proposed by Lo and Whitehead (2, 4), Chung and Dewar (3), Dewar and Harget (7), and Yamaguchiet al. (6) without using configuration interaction. It has been observed that spectral transitions calculated using the β-value proposed by Lo and Whitehead and Chung and Dewar are in good agreement with experiment and comparable to those calculated by the β-value proposed by Yamaguchiet al. and Dewaret al.

ISSN:0008-4042    

DOI:10.1139/v74-024

出版商:NRC Research Press    

年代:1974

数据来源: NRC

摘要:

In the range 600–700 °C and 20–100 mm Hg in Vycor vessels, the velocity of C3O2pyrolysis is proportional to the surface/volume ratio and its overall activation energy is also surface-sensitive. This reaction is first-order at the lower pressures and is strongly inhibited by NO. On the contrary, the reaction of C3O2with N2O is not inhibited by NO; it is first-order in each reactant, shows an overall activation energy of 52 kcal mol−1, and is partially surface dependent. Analysis shows the material balance 4C3O2 + N2O = N2 + CO2 + 7CO + 4C(s). We suggest a bimolecular heterogeneous initiation followed by a short chain of the type Cn + C3O2 → 2CO + Cn+1. The part played by C2O is discussed.

ISSN:0008-4042    

DOI:10.1139/v74-025

出版商:NRC Research Press    

年代:1974

数据来源: NRC

摘要:

The ultraviolet spectra of the d8complexes PtX42−, AuX4−, and Pd2X62−(X = Cl−or Br−) are reported. The assignments are based on a standard ordering of molecular orbital energy levels and on the trends in the band frequencies as related to the different metals and ligands. In addition to the low intensity d–d bands, two distinct high intensity regions are identified, an initial set of charge transfer ligand to metal bands followed by a sequence of essentially d → p bands. The 1849 Å irradiation of aqueous PtCl42−results in a redox reaction via photoelectron formation with.The primary photolytic act is interpreted as initial excitation of the d → p transition1A1g → 1Eu(3) (egπ* → a2uπ*).

ISSN:0008-4042    

DOI:10.1139/v74-026

出版商:NRC Research Press    

年代:1974

数据来源: NRC

摘要:

not available

ISSN:0008-4042    

DOI:10.1139/v74-027

出版商:NRC Research Press    

年代:1974

数据来源: NRC

摘要:

Irradiation with u.v. light of a methanolic solution of β-D-glucopyranosyl (1), α-D-mannopyranosyl (3), or β-D-galactopyranosyl (4) azide affords in good yield the corresponding next-lower aldose. In the case of β-maltosyl (6), β-D-ribofuranosyl (7), or α-L-arabinopyranosyl (8) azide, there was observed the formation of an intermediate which, on standing in the dark, reverts back to starting material.

ISSN:0008-4042    

DOI:10.1139/v74-028

出版商:NRC Research Press    

年代:1974

数据来源: NRC

摘要:

The reaction of diisopropyl formamide with lithium diisopropylamide produces, by abstraction of the formyl proton, the carbonyl anion, LiCON[CH(CH3)2]2. Reactions of this anion with benzaldehyde, benzophenone, ethyl benzoate, acetone, and propionaldehyde occur in yields ranging from 30–92%. Thus, this anion provides a useful method for the synthesis of α-hydroxy and α-keto acids, particularly in cases where cyanohydrin formation is difficult.

ISSN:0008-4042    

DOI:10.1139/v74-029

出版商:NRC Research Press    

年代:1974

数据来源: NRC

摘要:

o-Nitrophenylethylene glycol (1) was synthesized and found to be useful as a photochemically labile blocking group for aldehydes and ketones. The acetals obtained are cleaved smoothly upon irradiation at 3500 Å, regenerating the parent carbonyl compound in very good yield.

ISSN:0008-4042    

DOI:10.1139/v74-030

出版商:NRC Research Press    

年代:1974

数据来源: NRC