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Isotopic exchange of active methyl hydrogens. V. (1) Reactivity of α- and γ-methyl groups and β-hydrogens in pyrylium salts

✍ Scribed by Eugenia Gǎrd; Alice Vasilescu; G. D. Mateescu; A. T. Balaban

Publisher
John Wiley and Sons
Year
1967
Tongue
French
Weight
366 KB
Volume
3
Category
Article
ISSN
0022-2135

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✦ Synopsis

The deuteration and dedeuteration of 2,4,6-trimethylpyrylium perchlorate in water (D20 and HzO, respectively) was studied by nuclear magnetic resonance using as a quantitative standard for protons tetramethylammonium bromide. y-Methyl groups exchange faster than u-methyl groups; P-standing hydrogens exchange very slowly. A mechanism involving anhydrobase and pseudobase formation is discussed and theoretical calculations are mentioned. GeminaI hydrogen-deuterium spin-spin coupling in incompletely deuterated methyl groups is observed.

📜 SIMILAR VOLUMES

Isotopic exchange of active methyl hydro
Isotopic exchange of active methyl hydrogens. IV(1). Preparation of 1,3-di-d3-methylnaphthalene, d9-mesitylene and d9-mesitylene derivatives from 2,4,6-tri-d3-methylpyrylium perchlorate
✍ A. Barabas; Eugenia Gǎrd; Alice Vasilescu; A. T. Balaban 📂 Article 📅 1966 🏛 John Wiley and Sons 🌐 French ⚖ 385 KB

Starting ,from the easily available 2,4,6-tri-d3-methyIpyrylium perchlorate, the .following methyl-deuterated compounds were prepared : 1,3-dimethylnaphthalene III, nitromesitylene I V, mesidine V, mesitylenediazonium hydrogen sulphate VI, mesitylene VII, mesitol VIII and I-mesityleneazo-2-naphthol

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## Abstract Aldol reaction of 7‐chloro‐1,3‐dihydro‐1‐methyl‐5‐phenyl‐2__H__‐1,4‐benzodiazepin‐2‐one (**1**) with 4‐substituted __α__‐methylcinnamaldehydes **2**–**5** afforded a mixture of __threo__‐ and __erythro__‐3‐(3‐aryl‐1‐hydroxy‐2‐methylprop‐2‐enyl)‐7‐chloro‐1,3‐dihydro‐1‐methyl‐5‐phenyl‐2__