Phenyl carbamates, reactivity

Chroman, 4-( p-hydroxyphenyl)-2,2,4-trimethyl-X-ray studies, 3, 622 Chroman, 2-methoxy-synthesis, 3, 806 Chroman, 5-methoxy-synthesis, 3, 778 Chroman, 7-methoxy-synthesis, 3, 778 Chroman, 8-methoxy-acylation, 3, 732 Chroman, 2-methoxy-2-methyl-synthesis, 3, 780 Chroman, 2-methyl-synthesis, 3, 785 Chroman, 5-methyl-reactivity, 3, 732 Chroman, 6-nitro-synthesis, 3, 784 Chroman, 4-phenyl-synthesis, 3, 783 Chroman, thio-metabolism, 1, 241 Chroman, 5,6-thio-2-substituted metabolism, 1, 241 Chromanamines H NMR, 3, 580 Chroman-3-amines conformation, 3, 630 (S) -Chroman-2-carbaldehyde synthesis, 3, 779 Chromancarbaldehydes synthesis, 3, 782 Chroman-4-carbamic add synthesis, 3, 782 (R)-Chroman-2-carboxylic add methyl ester... 

The relative rates of these reaction sequences were found to depend on the nature of the medium (homogeneous or heterogeneous), rate of addition of water, temperature, reactivity of the amine (formed by the decomposition of the carbamic acid) with the isocyanate, concentration, and other factors. For example, in the reaction with phenyl isocyanate, cold water and heterogeneous medium favored the formation of diaryl urea while with boiling water the main product was aniline. Dilution also favored aniline formation. 

The metal-nitrogen bond in the adducts is often reactive toward protic reagents. The combination MOR/HOR can thus lead to overall formation of a carbamate by insertion of isocyanate into the M—O bond, followed by acidolysis of the adduct, as for the reactions of Bu3SnOMe/HOMe with phenyl isocyanate ... 

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