`R-NH-COH underset("pyridine")overset(POCl_(3))(to)` product. In the given reaction what will be the product.

Options

A. `R-N=C=O`
B. `N-overset(+)(N)-=C^(-)`
C. `R-C-=N`
D. None of these

Answer

To determine the product of the reaction of R-NH-COH with POCl3 in the presence of pyridine, we can follow these steps:

### Step 1: Identify the Reactants
The reactant is R-NH-COH, which is an amine (R-NH) with an aldehyde (COH) functional group.

### Step 2: Understand the Role of POCl3 and Pyridine
POCl3 (phosphoryl chloride) is a dehydrating agent. When used in the presence of pyridine, it facilitates the removal of water from the reaction mixture, which can lead to the formation of an imine or a related compound.

### Step 3: Mechanism of Reaction
1. The amine (R-NH) can react with the aldehyde (COH) to form a hemiaminal intermediate.
2. The presence of POCl3 promotes the dehydration of this hemiaminal, leading to the formation of an imine (R-N=CH).
3. The reaction can also lead to the formation of a double bond between nitrogen and carbon (N=C) if the nitrogen becomes positively charged and the carbon negatively charged.

### Step 4: Predict the Product
Given the dehydration process facilitated by POCl3 and pyridine, the final product will be an imine, which can be represented as R-N=CH.

### Conclusion
The product of the reaction R-NH-COH in the presence of POCl3 and pyridine is R-N=CH.

### Final Answer
The product is R-N=CH.

---