Sorry if I sound brutish, I'm just being honest. If you haven't taken inorganic or physical chemistry you will have no chance of getting into a top-tier chemistry Ph.D program. A low to mid-tier program might take you, and this is the route I took as I was in a similar situation as you. I studied biological sciences in undergrad, but after working in pharma I became more interested in chemistry and applied to a Ph.D program in organic chemistry. As I said, I went to a lower tier school because I also lacked inorganic and physical chemistry, but the school I went to allowed me to take these courses (although I wasn't allowed extra time to finish anything, I still had to finish both inorganic and physical chemistry as well as my required graduate courses by the end of my 2nd year, so my workload was considerably greater than those of my colleagues).
A few things you should consider:
1) There is a MASSIVE oversupply of Ph.D scientists, particularly in the pharmaceutical business that you seem to be interested in. Many of the jobs have been outsourced to Indian and Chinese scientists at a fraction of the cost and it's possible that many of these jobs will never return. Layoffs over the past two years number in the 10s of thousands, with some large research facilities being completely evacuated of all personnel. It may be easier for you to find a Bachelor's level position within one of these companies, although if you have your heart set on doing the synthetic chemistry you will not be a good candidate due to your focus on biological science and again, lack of full chemistry training (inorganic and P. chem).
2) If you do decide that you MUST go to grad school and get a Ph.D, going to a lower tier program will make your life challenging later as you will be competing with people from Stanford, Yale, and the like for the same positions. Unless you work for a well-known professor in your field/that professor is very good friends with such a person you will probably have to scrap and claw for good positions later.
3) In terms of isolating bioactive compounds from plants or other natural sources, you don't need to get an MD to do that. There are several research programs in analytical chemistry that do this exact type of research (my graduate institution happens to be one of them). If you are really interested in doing this, it might benefit you to research going to one of these institutions and finishing a BS in Chemistry (ie; doing physical and inorganic chemistry there) and trying to do research in one of these labs, rather than adding your name to the list of unemployed/underemployed Ph.Ds. However, as far as I know, most pharmaceutical companies that used to conduct this type of research have shut down their programs so you will not likely find this type of research opportunity with a company. But you WILL have solid analytical chemistry training and that is very valuable.