I'm a researcher interested in the fields of origins of Life, astrobiology and theoretical biology in general but I must admit I think my knowledge of chemistry outside biochemistry is a little bit limited. I'm well aware of the efforts to construct nucleic acid analogues and to construct expanded genetic codes with amino acids other than those found in the proteins in Nature but I wonder how far can we go as to construct a biochemistry which has nothing to do with our own? Is there anyone who had seriously investigated the question what kinds of compounds can be used to build a chemistry capable of providing the grounds for evolution into something we could classify as a lifeform? What classes of chemical compounds other than nucleic acids, proteins and lipids could develop into a real biochemistry? Are there any chemists who had seriously undertaken an effort to make such an investigation about classes of chemical compounds other than those known in biochemistry and if there are such efforts what molecules are they based on?

P.S. This is a question directed toward theoretical chemistry as much as it is a reference request, so I'm asking anyone who knows something about the matter to put their knowledge in the answer section whether it comes from fields related to biochemistry or not. From what I had researched so far there are some efforts to construct a biochemistry mimicking our own but my question isn't about biomimetics. I wonder could there be a biochemistry radically different from our own and how could I "screen" (or is that even possible) for classes of molecular species which could build it? I'm talking about a biochemistry not based on proteins or nucleic acids or even not having any type of "information" (whatever may stand behind such a word) at all. I'm asking this in the Chemistry SE because my interests are to learn could I select classes of molecular species which could do the job even in theory out of what we presently know about the possible diversity of chemical compounds or is our knowledge of all possible chemical compounds that could generate complex structures still too limited to shed any light on the questions of Life? Are we pass the point where we know enough about chemistry to theorize what molecules we could use to "build" a living organism or is there still a long way to go before we could say we know enough about all the possible molecules that can generate complexity? I want to know the answer to this question from a point of view of chemistry, not biology. I had enough experience with biologists and I could say the ones I met are too narrowed by biochemistry as we know it which I think is far from every possible biochemistry. Can you understand my background? Can you make any suggestions which fields of chemistry I should look into to find the answer to my query?

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    $\begingroup$ Long story short, we are not there yet. $\endgroup$ – Ivan Neretin Sep 25 '17 at 7:31
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    $\begingroup$ Is there no effort at all by chemists to tackle the question? I mean, at lease to suggest some compounds can generate complex structures that could turn out to have multiple functional abilities? I can't imagine the only thing able to produce life to be an ensemble of 20 amino acids and 4 nucleotides when there are so many compounds out there. Can chemists, al least suggest classes of compounds able to generate complex structures like amino acids and nucleic acids do? $\endgroup$ – Yordan Yordanov Sep 25 '17 at 10:18
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    $\begingroup$ @YordanYordanov I think the biggest issue is that until we actually encounter lifeforms that either don't use carbon as their main building block or use it very differently then we have seen, it would be very difficult to determine what is feasible due to the vast space of possible compounds that we could generate. I think until we something remotely different than how life is composed here, it is very difficult to picture an alternative to proteins, DNA, etc. This Wikipedia page might link to some articles of interest: en.wikipedia.org/wiki/Hypothetical_types_of_biochemistry $\endgroup$ – Tyberius Sep 25 '17 at 14:31
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    $\begingroup$ chemistry.stackexchange.com/questions/70009/… $\endgroup$ – Mithoron Sep 25 '17 at 14:35
  • $\begingroup$ I just want to know how can I "screen" for compounds that can participate in a possible biochemistry out of the millions we had managed to create up until now. I think this is an issue which has a lot to do with chemistry and my question is right on the spot here. So, what's wrong with it? $\endgroup$ – Yordan Yordanov Sep 27 '17 at 20:03