Date of Graduation

1973

Document Type

Dissertation

Degree Type

PhD

Department

Chemistry

Committee Chair

C. Gordon McCarty

Committee Co-Chair

V.J. Traynellis

Committee Member

H. Resnick

Committee Member

P. Popovich

Committee Member

J.T. Maloy

Abstract

The Chapman rearrangement of dimethyl N-cyanoimidocarbonate (89), dimethyl N-cyanothioimidocarbonate (90), and N,N-dimethyl-N′-cyanomethylisourea (91) has been investigated. N-cyanotrimethylurea (24), the normal Chapman rearrangement product of 91, was observed along with several other compounds when 91 was heated neat for several hours. Among the products of the rearrangement of 91 were three isomeric oxadiazines. These compounds were probably formed by a 1,4 addition of an N-acyl carbodiimide (resulting from a 1,4 O→N migration of the methyl group in 91) across the cyano group of compound 91. In contrast to 91, 89 and 90, upon being heated, underwent quantitative conversion to the corresponding carbamate and thiocarbamate, respectively. The kinetics of the Chapman rearrangement of 89 and 90 in bromobenzene were followed by both NMR and IR spectroscopy, with the latter being the better method. Both 89 and 90 were found to obey first-order kinetics. The rate constants (IR method) for 89 ranged from 3.20 ± 0.10 × 10⁻⁵ sec⁻¹ at 100° to 36 ± 1.3 × 10⁻⁵ sec⁻¹ at 130°, and the Eₐ, ΔH‡, and ΔS‡ were 24.2 ± 0.5 kcal/mol, 23.5 ± 0.49 kcal/mol, and −17 ± 2.0 eu, respectively, for this compound. The rate constants (IR method) for compound 90 ranged from 4.8 ± 0.22 × 10⁻⁵ sec⁻¹ at 120° to 50 ± 5.0 × 10⁻⁵ sec⁻¹ at 150°, while the Eₐ…

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