OC questions

[nhasifuture]

can anyone help me to assign priority to the following substituents: OH, CHO, COOH, CH2OH. thanks!

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[far123]

can anyone help me to assign priority to the following substituents: OH, CHO, COOH, CH2OH. thanks!

when u wanna assign priority, look at the elements one by one..
OH has oxygen so it is#1, COOH is second (think of double bond as if u have coooH)and CHo is #3 and (CHOO), and CH2oH is #4

 

[PooyaH]

Always assign the atom that has the highest molecular weight, the highest priority number! Keep in mind that it only counts for the first atom attached to the chiral carbon!

 

[Thundercatz]

You actually assign by highest atomic number!

 

[PooyaH]

yes yes yes! sorry mass number or atomic number! I got them mixed for a sec 😀

 

[Andrew324]

So then whats the offical answer?

 

[PooyaH]

So then whats the offical answer?

Atomic number! but mass number is used for isotopes which I don't think we need to know that for the DAT!

 

[Andrew324]

But for this problem

 

[PooyaH]

But for this problem

Atomic Number!

 

[Andrew324]

Atomic Number!

Yes but

can anyone help me to assign priority to the following substituents: OH, CHO, COOH, CH2OH. thanks!

do that

 

[PooyaH]

Yes but

can anyone help me to assign priority to the following substituents: OH, CHO, COOH, CH2OH. thanks!

do that

oh haha sorry man!

1. OH
2. COOH
3. COH
4. CH2OH

 

[nhasifuture]

thanks so much guys!!!

 

[klutzy1987]

oh haha sorry man!

1. OH
2. COOH
3. COH
4. CH2OH

The COOH has the highest priority, followed by the COH followedby the OH followed by the CH2OH.
1)COOH
2)COH
3)OH
4)CH2OH

But this is for nomenclature, not for RS. For RS what pooyah said would be correct.