3. The mechanism of the reaction of aryl isocyanates with alcohols and amines. Part II. The base-catalysed reaction of phenyl isocyanate with alcohols

1949 ◽  
pp. 9 ◽  
Author(s):  
John W. Baker ◽  
J. Gaunt
Keyword(s):  
Phenyl Isocyanate ◽  
Catalysed Reaction ◽  
Aryl Isocyanates ◽  
Mechanism Of The Reaction

Cu(i) catalysed annulation of isothiocyanates/isocyanates with 2-iodo-sulfonamides: synthesis of benzodithiazines, benzothiadiazinones, benzothiazinylidene-anilines and benzothiazolylidene-anilines

2019 ◽  
Vol 17 (28) ◽  
pp. 6880-6894 ◽  
Author(s):  
K. Sandeep ◽  
Alla Siva Reddy ◽  
K. C. Kumara Swamy
Keyword(s):  
Catalysed Reaction ◽  
Aryl Isocyanates ◽  
Aryl Isothiocyanates

Cu(i)-catalysed reaction of 2-iodobenzene sulfonamides with aryl isothiocyanates leads to benzodithiazines but the corresponding reaction with aryl isocyanates affords benzothiadiazinones.

The Mechanism of the Alkali catalysed Phenol-Formaldehyde reaction

1955 ◽  
Vol 8 (2) ◽  
pp. 194 ◽  
Author(s):  
JS Fitzgerald ◽  
RJL Martin
Keyword(s):  
Induction Period ◽  
Aldol Condensation ◽  
Phenol Formaldehyde ◽  
Kinetic Studies ◽  
Bimolecular Reaction ◽  
Hydrogen Ion ◽  
Catalysed Reaction ◽  
Alkaline Reaction ◽  
Cannizzaro Reaction ◽  
Mechanism Of The Reaction

Kinetic studies on the 2,3,4,5-tetramethylphenol(prehnitenol)- and 2,6-xylenol-formaldehyde reactions indicate that the alkali catalysed reaction is not a simple bimolecular reaction. The rate of the 2,6-xylenol-formaldehyde reaction in the presence of excess alkali has been shown to be proportional to [phenoxide]1.4 [formaldehyde]1.4 [free alkali]-0.4. The mechanism of the reaction has been interpreted as a reaction between the phenoxide ion and CH2=O together with other simultaneous reactions. It is unlikely that the +CH2OH plays any part in the alkali catalysed reaction. Attempts have been made to interpret the results on the basis that a hemiformal rearranges to a phenol alcohol and that the ion +CH2OPh reacts with a phenoxide ion. In any case it is not possible to give a complete mechanism with certainty. The degree of formation of hemiformal is too small to be detected by hydrogen ion measurements. When the Cannizzaro reaction of formaldehyde is carried out in the presence of a phenol, the phenoxide Ions catalyse a condensation which 1s presumably an aldol condensation. This reaction having a long induction period and being autocatalytic does not assume importance In the early stages of the reaction. A compound, probably 2,2'-dihydroxy-3,3',4,4',5,5',6,6'-octamethyldiphenylmethane, has been isolated from the alkaline reaction between prehnitenol and formaldehyde.

Synthesis of 2-aryl-2H-indazoles by base catalysed reaction of 2-nitrobenzyl triphenylphosphonium bromide and aryl isocyanates

2000 ◽  
Vol 41 (50) ◽  
pp. 9893-9897 ◽  
Author(s):  
Abutariq Taher ◽  
Sweta Ladwa ◽  
Srinath Thirumalai Rajan ◽  
George W Weaver
Keyword(s):  
Catalysed Reaction ◽  
Aryl Isocyanates ◽  
Triphenylphosphonium Bromide
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