Penicillin Chemical formula

FIGURE 1,12. (a) Chemical formula and (b) stereoview of the potassium salt of the benzyl derivative of the antibiotic penicillin. This crystallographic analysis established this chemical formula of penicillin showing that it contained, unexpectedly, a / -lactam (four-membered) ring. Circles representing atoms S, large stippled 0, small stippled N, small black C, small white K+, very small black hydrogen atoms omitted. 

The first piece of information obtained from a structure determination is the connectivity of atoms. This leads to the chemical formula, if previously unknown. Penicillin and vitamin B12 (see Figures 1.12 and 1.13, Chapter 1) are examples of compounds for which X-ray diffraction analyses established the atomic connectivity and, as a result, the chemical formulas and subsequent geometries of these molecules. Other examples include the boron hydrides, which were found to have unexpected arrangements of atoms. For many of these compounds the atomic connectivity was not known before the X-ray diffraction analyses. 

Chemical Name Penicillin G compound with N,N -dibenzylethylenediamine Common Name Benzethacil Structural Formula ... 

Chemical Name a-Carboxy-a-(3-thienyl)methyl penicillin disodium salt Common Name -Structural Formula ... 

It should be emphasized that in almost every instance, the purely chemical work on penicillin proved susceptible to more than one plausible interpretation, and that although the now accepted formula (above) was first derived and supported on the basis of chemical arguments, it was not at first widely accepted. The physical evidence and, in particular, the magnificent X-ray crystallographic work was ultimately conclusive. 

---