Are imides acidic or basic?
As expected, imides are more acidic and less basic than amides as suggested by the resonance structures in Fig. 1-iii.
Are imides acidic?
The N–H center for imides derived from ammonia is acidic and can participate in hydrogen bonding. Unlike the structurally related acid anhydrides, they resist hydrolysis and some can even be recrystallized from boiling water.
What is the pKa of an imine?
approximately 7
Recall from section 7.5B that imines have a pKa of approximately 7, so at physiological pH they can be accurately drawn as either protonated (iminium ion form) or neutral (imine).
What is the pKa of aniline?
4.63
Like other amines, aniline is both a base (pKaH = 4.6) and a nucleophile, although less so than structurally similar aliphatic amines….Aniline.
| Names | |
|---|---|
| Boiling point | 184.13 °C (363.43 °F; 457.28 K) |
| Solubility in water | 3.6 g/100 mL at 20 °C |
| Vapor pressure | 0.6 mmHg (20° C) |
| Acidity (pKa) | 4.63 (conjugate acid; H2O) |
Are Imides basic?
Amides are very weak bases (weaker than water). Imides are less basic yet and in fact react with strong bases to form salts. That is, they can react as acids.
Are Imides reactive?
Imides are less basic yet and in fact react with strong bases to form salts. That is, they can react as acids. Mixing amides with dehydrating agents such as P2O5 or SOCl2 generates the corresponding nitrile.
What is the pKa of a ketone?
The alpha-hydrogens of ketones (pKa = 20) are less acidic as compared to aldehydes (pKa = 17). This is because the alkyl group R” of ketones pushes electrons via inductive effect on to the alpha-carbon.
What is the pKa of ethanol?
16.0
pKa Values for Organic and Inorganic Bronsted Acids at 25 oC
| Name | pKa |
|---|---|
| Water | 15.74 |
| Ethanol | 16.0 |
| Cyclohexanone | 16.7 |
| Acetamide | 17 |
What is the pKa of phenol?
The pKa value for phenol is 10.0, and two series of substituted phenols are given: 2-fluorophenol, 3-fluorophenol, and 4-fluorophenol have pKa values of 8.7, 9.3, and 9.9, respectively; 2-nitrophenol, 3-nitrophenol, and 4-nitrophenol have pKa values of 7.2, 8.4, and 7.2, respectively.
Does the cyclic imine have a pKa of 9?
I have been trying to find the original data for the statement that the cyclic imine (or rather its conjugate acid) has a pKa of around 9. Typically, imines have a pKa between 5 and 7, so this seems unusually high for a start. If this number is wrong then it means that pyridine may have quite a typical pKa for a cyclic imine of this type.
What does this pKa of pyridine mean?
Typically, imines have a pKa between 5 and 7, so this seems unusually high for a start. If this number is wrong then it means that pyridine may have quite a typical pKa for a cyclic imine of this type. I’ve not had time for a detailed search but I suspect this number may not be fully accurate.
What is the best method for the synthesis of cyclic imides?
The reaction of cyclic anhydrides with amines is perhaps the best established and most widely used method for the synthesis of cyclic imides. As befits its importance, there have been a large number of reports involving application of improved reaction conditions or catalysts to this method.
What are the synthetic approaches to the synthesis of pyrrolidines?
The synthetic approaches are divided into fragment-based methods, oxidation of pyrrolidines and lactams, ring expansion and ring contraction, and N- and C-functionalization of imides.
