In the early 1960s, Eschenmoser began work on what was the most complex natural product synthesized at the time—vitamin B12. In a remarkable collaboration with his colleague Robert Burns Woodward in Harvard, a team of almost one hundred students and postdoctoral workers worked for many years on the synthesis of this molecule. The work was finally published in 1973, and it marked a landmark in the history of organic chemistry.
Threose nucleic acid is an artificial genetic polymer invented by Albert Eschenmoser. TNA strings composed of repeating threose sugars linked together by phosphodiester bonds. Like DNA and RNA, TNA can store genetic information in strings of nucleotide sequences (G, A, C, and T). A researcher at the Center for Evolutionary Medicine, John Chaput,has theorized that issues concerning the prebiotic synthesis of ribose sugars and the non-enzymatic replication of RNA may provide circumstantial evidence of an earlier genetic system more readily produced under primitive earth conditions. TNA could have been an early pre dna genetic system.