What should an undefined R-group mean in searching?

We would like to make query and reaction scheme drawing easier by supporting undefined R-groups. In this case, no other substitutions will be allowed on the scaffold (all hydrogens are considered explicit). For example, R-CH2-OH will mean ethyl alcohol, propyl alcohol, butyl alcohol, etc., but not diethyl ether or isopropyl alcohol.





The question is:


Does R-CH2-OH represent methyl alcohol as well? Can R mean hydrogen in this case?


Yes? But what about an R-disubstituted benzene, can R mean hydrogen in this case as well?


Can R be an OH? Do you think, that R-CH2-OH can mean hydrate?





If you are a chemist, we are interested in your opinion. Please write your opinion here and vote!

Opinion one:





"What you mention is one of the most important and difficult problems. The type of structures you mention is name Marhush structures. The R group is in fact for the chemist context dependant. So the computer will never understand what the chemist want to say because usually the search on sytructural feature is context independent.





What about the thinking of the chemist R group is expeted to be an unreactive alkyl group that does not means that it does not change the reactivity of the group to which it is attached. It usually cannot also change the name of the functional group to which it is attached(so if R includes H aldehydes and ketones cannot be differentiated.





Of course R group is not always an alkyl group but it is assumed in a contexte of a reaction to be inert… If it is so another functional group has to be far from the reactive group if R is attach to a functional group (usually three or four carbon apart from the functional group.





RCH2OH: R cannot be an OH (hydrate), OMe (hemiacetal), Me-C(=O)- (alpha hydroxyl ketone).





R1-C(=O)R2 one of the R cannot be an hydroxyl group (carboxylic acid), but can be MeOC(=O)-CH2- CH2- CH2- C(=O)Me if the ester group is not reacting





In fact you can imagine that R1-C(=O)R2 represent the family of compound who bears the ketone functional group.





You can know decide if R is H that you represent in such way the family of carbonyl compounds which include the sub-groups of compounds possessing either the aldeyde or ketone functional groups."

Opinion two:





"R can be whatever you define it as. It is often defined as H or alkyl. So I would say, yes, let R be H."

In any chemical reaction, you define, what R should be, inclusions and exclusions as well. I say let R be H, as well. A good chemist always checks on neighbouring functional groups before mixing the reactants. A bad chemist only cooks a recipe.